 2010 Microchip Technology Inc. DS51865B HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 2  2010 Microchip Technology Inc. Information contained in this publication regarding device applications and the like is provided only for your convenience and may be superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR OTHERWISE, RELATED TO THE INFORMATION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE, MERCHANTABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Microchip devices in life support and/or safety applications is entirely at the buyer’s risk, and the buyer agrees to defend, indemnify and hold harmless Microchip from any and all damages, claims, suits, or expenses resulting from such use. No licenses are conveyed, implicitly or otherwise, under any Microchip intellectual property rights. Trademarks The Microchip name and logo, the Microchip logo, dsPIC, KEELOQ, KEELOQ logo, MPLAB, PIC, PICmicro, PICSTART, PIC32 logo, rfPIC and UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. FilterLab, Hampshire, HI-TECH C, Linear Active Thermistor, MXDEV, MXLAB, SEEVAL and The Embedded Control Solutions Company are registered trademarks of Microchip Technology Incorporated in the U.S.A. Analog-for-the-Digital Age, Application Maestro, CodeGuard, dsPICDEM, dsPICDEM.net, dsPICworks, dsSPEAK, ECAN, ECONOMONITOR, FanSense, HI-TIDE, In-Circuit Serial Programming, ICSP, Mindi, MiWi, MPASM, MPLAB Certified logo, MPLIB, MPLINK, mTouch, Omniscient Code Generation, PICC, PICC-18, PICDEM, PICDEM.net, PICkit, PICtail, REAL ICE, rfLAB, Select Mode, Total Endurance, TSHARC, UniWinDriver, WiperLock and ZENA are trademarks of Microchip Technology Incorporated in the U.S.A. and other countries. SQTP is a service mark of Microchip Technology Incorporated in the U.S.A. All other trademarks mentioned herein are property of their respective companies. © 2010, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved. Printed on recycled paper. ISBN: 978-1-60932-739-2 Note the following details of the code protection feature on Microchip devices: • Microchip products meet the specification contained in their particular Microchip Data Sheet. • Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the intended manner and under normal conditions. • There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Data Sheets. Most likely, the person doing so is engaged in theft of intellectual property. • Microchip is willing to work with the customer who is concerned about the integrity of their code. • Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not mean that we are guaranteeing the product as “unbreakable.” Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our products. Attempts to break Microchip’s code protection feature may be a violation of the Digital Millennium Copyright Act. If such acts allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act. Microchip received ISO/TS-16949:2002 certification for its worldwide headquarters, design and wafer fabrication facilities in Chandler and Tempe, Arizona; Gresham, Oregon and design centers in California and India. The Company’s quality system processes and procedures are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping devices, Serial EEPROMs, microperipherals, nonvolatile memory and analog products. In addition, Microchip’s quality system for the design and manufacture of development systems is ISO 9001:2000 certified.  2010 Microchip Technology Inc. DS51865B-page 3 HI-TECH C® FOR PIC10/12/16 USER’S GUIDE Table of Contents Chapter 1. HI-TECH C Compiler for PIC10/12/16 MCUs 1.1 Introduction ..................................................................................................... 5 1.2 Compiler Description and Documentation ...................................................... 5 1.3 Device Description ......................................................................................... 5 Chapter 2. PICC Command-line Driver 2.1 Introduction ..................................................................................................... 7 2.2 Invoking the Compiler ..................................................................................... 7 2.3 The Compilation Sequence ............................................................................ 9 2.4 Runtime Files ............................................................................................... 15 2.5 Compiler Output ........................................................................................... 16 2.6 Compiler Messages ...................................................................................... 18 2.7 PICC Driver Option Descriptions .................................................................. 22 2.8 MPLAB IDE Universal Toolsuite Equivalents ............................................... 42 Chapter 3. C Language Features 3.1 Introduction ................................................................................................... 47 3.2 ANSI C Standard Issues .............................................................................. 47 3.3 Processor-related Features .......................................................................... 47 3.4 Supported Data Types and Variables .......................................................... 54 3.5 Memory Allocation and Access .................................................................... 70 3.6 Operators and Statements ........................................................................... 80 3.7 Register Usage ............................................................................................. 82 3.8 Functions ...................................................................................................... 82 3.9 Interrupts ...................................................................................................... 86 3.10 Psects ......................................................................................................... 90 3.11 Main, Runtime Startup and Reset .............................................................. 93 3.12 Library Routines ......................................................................................... 96 3.13 Mixing C and Assembly Code .................................................................... 97 3.14 Optimizations ............................................................................................ 103 3.15 Preprocessing .......................................................................................... 104 3.16 Linking Programs ..................................................................................... 112 Chapter 4. Macro Assembler 4.1 Assembler Usage ....................................................................................... 115 4.2 Options ....................................................................................................... 116 4.3 HI-TECH C Assembly Language ................................................................ 119 4.4 Assembly List Files ..................................................................................... 137 HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 4  2010 Microchip Technology Inc. Chapter 5. Linker 5.1 Introduction ................................................................................................. 141 5.2 Operation .................................................................................................... 141 5.3 Relocation and Psects ................................................................................ 148 5.4 Map Files .................................................................................................... 149 Chapter 6. Utilities 6.1 Introduction ................................................................................................. 155 6.2 Librarian ..................................................................................................... 155 6.3 Objtohex ..................................................................................................... 158 6.4 Cref ............................................................................................................. 159 6.5 Cromwell .................................................................................................... 162 6.6 Hexmate ..................................................................................................... 165 Chapter 7. Library Functions Chapter 8. Error and Warning Messages ................................................................241 Appendix A. Implementation-Defined Behavior A.1 Translation (G.3.1) ..................................................................................... 343 A.2 Environment (G.3.2) ................................................................................... 343 A.3 Identifiers (G.3.3) ....................................................................................... 343 A.4 Characters (G.3.4) ..................................................................................... 344 A.5 Integers (G.3.5) .......................................................................................... 344 A.6 Floating-Point (G.3.6) ................................................................................. 345 A.7 Arrays and Pointers (G.3.7) ....................................................................... 345 A.8 Registers (G.3.8) ........................................................................................ 346 A.9 Structures, Unions, Enumerations, and Bit-Fields (G.3.9) ......................... 346 A.10 Qualifiers (G.3.10) .................................................................................... 347 A.11 Declarators (G.3.11) ................................................................................ 347 A.12 Statements (G.3.12) ................................................................................. 347 A.13 Preprocessing Directives (G.3.13) ........................................................... 347 A.14 Library Functions (G.3.14) ....................................................................... 348 Index ...........................................................................................................................351 Worldwide Sales and Service ...................................................................................364 HI-TECH C® FOR PIC10/12/16 USER’S GUIDE  2010 Microchip Technology Inc. DS51865B-page 5 Chapter 1. HI-TECH C Compiler for PIC10/12/16 MCUs 1.1 INTRODUCTION This chapter provides an overview of the HI-TECH C Compiler for PIC10/12/16 MCUs. 1.2 COMPILER DESCRIPTION AND DOCUMENTATION The HI-TECH C Compiler for PIC10/12/16 MCUs is a free-standing, optimizing ANSI C compiler. It supports all PIC10, PIC12 and PIC16 series devices, as well as the PIC14000 device and the enhanced Mid-Range PIC® MCU architecture. The compiler is available for several popular operating systems, including 32 and 64-bit Windows® , Linux and Apple OS X. The compiler can run in one of three operating modes: Lite, Standard or PRO. The Standard and PRO operating modes are licensed modes and require a serial number to enable them. Lite mode is available for unlicensed customers. The basic compiler operation, supported devices and available memory are identical across all modes. The modes only differ in the level of optimization employed by the compiler. 1.2.1 Conventions Throughout this manual, the term “the compiler” is often used. It can refer to either all, or some subset of, the collection of applications that form the HI-TECH C Compiler for PIC10/12/16 MCUs. Often it is not important to know, for example, whether an action is performed by the parser or code generator application, and it is sufficient to say it was performed by “the compiler”. It is also reasonable for “the compiler” to refer to the command-line driver (or just driver) as this is the application that is always executed to invoke the compilation process. The driver for the HI-TECH C Compiler for PIC10/12/16 MCUs package is called PICC. The driver and its options are discussed in Section 2.7 “PICC Driver Option Descriptions”. Following this view, “compiler options” should be considered command-line driver options, unless otherwise specified in this manual. Similarly “compilation” refers to all, or some part of, the steps involved in generating source code into an executable binary image. 1.3 DEVICE DESCRIPTION This compiler supports Microchip PIC devices with Baseline, Mid-Range and Enhanced Mid-Range cores. All are 8-bit devices. The Baseline core uses a 12-bit wide instruction set and is available in PIC10, PIC12 and PIC16 part numbers. The Mid-Range core utilizes a 14-bit wide instruction set that includes additional instructions to those provided by Baseline parts. Its data memory banks and program memory pages are larger than those on Baseline devices. It is available in PIC12, PIC14 and PIC16 part numbers. The Enhanced Mid-Range core also uses a 14-bit wide instruction set, but incorporates additional instructions and features over the Mid-Range devices. There are both PIC12 and PIC16 part numbers that are based on the Enhanced Mid-Range core. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 6  2010 Microchip Technology Inc. The compiler takes advantage of the target device’s instruction set, addressing modes memory and registers where ever possible. See Section 2.7.21 “--CHIPINFO: Display List of Supported Processors” for information on finding the full list of devices supported by your compiler version. HI-TECH C® FOR PIC10/12/16 USER’S GUIDE  2010 Microchip Technology Inc. DS51865B-page 7 Chapter 2. PICC Command-line Driver 2.1 INTRODUCTION The command-line driver is called PICC and is the application that can be invoked to perform all aspects of compilation, including C code generation, assembly and link steps. Even if you use an IDE to assist with compilation, the IDE will ultimately call PICC. Although the internal compiler applications can be called explicitly from the command line, using PICC is the recommended way to use the compiler as it hides the complexity of all the internal applications used and provides a consistent interface for all compilation steps. This chapter describes the steps the driver takes during compilation, files that the driver can accept and produce, as well as the command-line options that control the compiler’s operation. It also shows the relationship between these command-line options and the controls in the MPLAB IDE Build Options dialog. 2.2 INVOKING THE COMPILER 2.2.1 Driver Command-line Format This section looks at how to use PICC as well as the tasks that it, and the internal applications, perform during compilation. PICC has the following basic command format. PICC [options] files [libraries] It is assumed in this manual that the compiler applications are either in the console’s search path, or the full path is specified when executing any application. The compiler’s location can be added to the search path when installing the compiler by selecting the Add to environment checkbox in the install program. It is conventional to supply options (identified by a leading dash “-” or double dash “–”) before the filenames, although this is not mandatory. The formats of the options are listed in Section 2.7 “PICC Driver Option Descriptions”, with a detailed description of each option. The files may be any mixture of C and assembler source files, and precompiled intermediate files, such as relocatable object (.obj) files or p-code (.p1) files. The order of the files is not important, except that it may affect the order in which code or data appears in memory, and may affect the name of some of the output files. Libraries is a list of user-defined object code or p-code library files that will be searched by the linker in addition to the standard C libraries. The order of these files will determine the order in which they are searched. They are typically placed after the source filename, but this is not mandatory. If you are building code using a make system, ensure you are familiar with the unique intermediate file format as described in Section 2.3.3 “Multi-step Compilation”. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 8  2010 Microchip Technology Inc. 2.2.1.1 LONG COMMAND LINES The PICC driver is capable of processing command lines exceeding any operating system limitation. To do this, the driver may be passed options via a command file. The command file is specified by using the @ symbol which should be immediately followed (i.e. no intermediate space character) by the name of the file containing the command line arguments intended for the driver. Each command-line argument must be separated by one or more spaces and may be placed over several lines by using a space and backslash character to separate lines. The file may contain blank lines, which are simply skipped by the driver. The use of a command file means that compiler options and project filenames can be stored along with the project, making them more easily accessible and permanently recorded for future use, but without involving the complexity of creating a make utility. For example, a command file xyz.cmd is constructed in any text editor and contains both the options and file names that are required to compile your project as follows. --chip=16F877A -m \ --opt=all -g \ main.c isr.c After it is saved, the compiler may be invoked with the command: PICC @xyz.cmd 2.2.2 Environment Variables When hosted on a Windows environment, the compiler uses the registry to store information relating to the compiler installation directory and activation details, along with other configuration settings. Under Linux and Apple OS X, the registry is replaced by an XML file which stores the same information. This information is necessary regardless of whether the compiler is run on the command line or from within an IDE. The compiler tries to finds the location of this XML file in several ways. First, the compiler looks for the presence of an environment variable called HTC_XML. If present, this variable should contain the full path to the XML file (including the file’s name). If this variable is not defined, the compiler then searches for an environment variable called HOME. This variable typically contains the path to the user’s home directory. The compiler looks for the XML with a name htsoft.xml in the directory indicated by the HOME variable. If the HOME environment variable is not defined, the compiler tries to open the file /etc/htsoft.xml. If none of these methods finds the XML file, an error is gen- erated. When running the compiler on the command line, you may wish to set the PATH environment variable. This allows you to run the compiler driver without having to specify the full compiler path with the driver name. Note that the directories specified by the PATH variable are only used to locate the compiler driver. Once the driver is running, it uses the registry or XML file, described above, to locate the internal compiler applications, such as the parser, assembler and linker etc. The directories specified in the PATH variable do not override the information contained in the registry or XML file. The MPLAB IDE allows the compiler to be selected via a dialog and execution of the compiler does not depend on the PATH variable. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 9 2.2.3 Input File Types PICC distinguishes source files, intermediate files and library files solely by the file type, or extension. Recognized file types are listed in Table 2-1. Alphabetic case of the extension is not important from the compiler’s point of view, but most operating system shells are case sensitive. This means, for example, that a C source file must have a .c extension. Assembler files can use either .as or .asm extensions. The terms “source file” and “module” are often used when talking about computer programs. They are often used interchangeably, but they refer to the source code at different points in the compilation sequence. A source file is a file that contains all or part of a program. Source files are initially passed to the preprocessor by the driver. A module is the output of the preprocessor, for a given source file, after inclusion of any header files (or other source files) which are specified by #include preprocessor directives. These modules are then passed to the remainder of the compiler applications. Thus, a module may consist of several source and header files. A module is also often referred to as a translation unit. These terms can also be applied to assembly files, as they too can include other header and source files. 2.3 THE COMPILATION SEQUENCE 2.3.1 The Compiler Applications The main internal compiler applications and files are illustrated in Figure 2-1. You can consider the large underlying box to represent the whole compiler, which is controlled by the command line driver, PICC. You may be satisfied just knowing that C source files (shown on the far left) are passed to the compiler and the resulting output files (shown here as a HEX and COFF debug file on the far right) are produced; however internally there are many applications and temporary files being produced. An understanding of the internal operation of the compiler, while not necessary, does assist with using the tool. The driver will call the required compiler applications. These applications are shown as the smaller boxed inside the large driver box. The temporary file produced by each application can also be seen in this diagram. TABLE 2-1: PICC INPUT FILE TYPES File Type Meaning .c C source file .p1 p-code file .lpp p-code library file .as or .asm Assembler source file .obj Relocatable object code file .lib Relocatable object library file .hex Intel HEX file HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 10  2010 Microchip Technology Inc. FIGURE 2-1: COMPILER APPLICATIONS AND FILES Table 2-2 lists the compiler applications. The names shown are the names of the executables, which can be found in the bin directory under the compiler’s installation directory. .as preprocessor parser code generator assembler.c .pre .p1 .obj processed files (module) p-code files assembly file relocatable object file C source files orp linker objtohex cromwell hexmate parser code generator assembler linker objtohex cromwell .obj absolute object file .hex hex file .cof debug file .hex hex file .c .h Command-line driver .lppp-code libraries .as assembly source files .objrelocatable object files .hexhex files .lib object libraries .p1 p-code files TABLE 2-2: COMPILER APPLICATION NAMES Name Description PICC Command line driver; the interface to the compiler CLIST Text file formatter CPP The C preprocessor P1 C code parser CGPIC Code generator ASPIC Assembler HLINK Linker OBJTOHEX Conversion utility to create HEX files CROMWELL Debug file converter OBJTOHEX Conversion utility to create HEX files HEXMATE HEX file utility LIBR Librarian DUMP Object file viewer CREF Cross reference utility PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 11 For example, C source files (.c files) are first passed to the C preprocessor, CPP. The output of this application are .pre files. These files are then passed to the parser application, P1, which produces a p-code file output with extension .p1. The applications are executed in the order specified and temporary files are used to pass the output of one application to the next. The compiler can accept more than just C source files. Table 2-1 lists all the possible input file types, and these files can be seen in this diagram, on the top and bottom, being passed to different compilation applications. They are processed by these applications and then the application output joins the normal flow indicated in the diagram. For example, assembly source files are passed straight to the assembler application1 and are not processed at all by the code generator. The output of the assembler (an object file with .obj extension) is passed to the linker in the usual way. You can see that any p-code files (.p1 extension) or p-code libraries (.lpp extension) that are supplied on the command line are initially passed to the code generator. Other examples of input files include object files (.obj extension) and object libraries (.lib extension), both of which are passed initially to the linker, and even HEX files (.hex extension), which are passed to one of the utility applications, called HEXMATE, which is run right at the end of the compilation sequence. Some of the temporary files shown in this diagram are actually preserved and can be inspected after compilation has concluded. There are also driver options to request that the compilation sequence stop after a particular application and the output of that application becomes the final output. FIGURE 2-2: MULTI-FILE COMPILATION 2.3.2 Single-step Compilation Figure 2-1 showed us the files that are generated by each application and the order in which these applications are executed. However this does not indicate how these applications are executed when there is more than one source file being compiled. Consider the case when there are two C source files that form a complete project and that are to be compiled, as is the case shown in Figure 2-2. If these files are called main.c and io.c, these could be compiled with a single command, such as: PICC --chip=16F877A main.c io.c 1. Assembly file will be preprocessed before being passed to the assembler if the -P option is selected. C file C file library files preprocess & parse p- code code generation preprocess & parse pcode linkassemble First stage of compilation Second stage of compilation Intermediate files HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 12  2010 Microchip Technology Inc. This command will compile the two source files all the way to the final output, but internally we can consider this compilation as consisting of two stages. The first stage involves processing of each source file separately, and generating some sort of intermediate file for each source file. The second stage involves combining all these intermediate files and further processing to form the final output. An intermediate file is a particular temporary file that is produced and marks the mid point between the first and second stage of compilation. The intermediate file used by PICC is the p-code (.p1 extension) file output by the parser, so there will be one p-code file produced for each C source file. As indicated in the diagram, CPP and then P1 are executed to form this intermediate file. (For clarity the CPP and P1 applications have been represented by the same block in the diagram.) In the second stage, the code generator reads in all the intermediate p-code files and produces a single assembly file output, which is then passed to the subsequent applications that produce the final output. The desirable attribute of this method of compilation is that the code generator, which is the main application that transforms from the C to the assembly domain, sees the entire project source code via the intermediate files. Traditional compilers have always used intermediate files that are object files (.obj extension) output by the assembler. These intermediate object files are then combined by the linker and further processed to form the final output. This method of compilation is shown in Figure 2-3 and shows that the code generator is executed once for each source file. Thus the code generator can only analyze that part of the project that is contained in the source file currently being compiled. Using object files as the intermediate file format with HI-TECH C Compiler for PIC10/12/16 MCUs will defeat many features the compiler uses to optimize code. Always use p-code files as the intermediate file format if you are using a make system to build projects. FIGURE 2-3: THE TRADITIONAL COMPILATION SEQUENCE When compiling files of mixed types, this can still be achieved with just one invocation of the compiler driver. As discussed in Section 2.3 “The Compilation Sequence”, the driver will pass each input file to the appropriate compiler application. For example, the files, main.c, io.c, mdef.as and c_sb.lpp are to be compiled. To perform this in a single step, the following command line could be used. PICC --chip=16F877A main.c io.c mdef.as c_sb.lpp C file C file library files preprocess & parse .obj files preprocess & parse .obj files link assemble First stage of compilation Second stage of compilation Intermediate files code generation code generation assemble PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 13 As shown in Figure 2-1 and Figure 2-2, the two C files (main.c and io.c) will be compiled to intermediate p-code files; these, along with the p-code library file (c_sb.lpp) will be passed to the code generator. The output of the code generator, as well as the assembly source file (mdef.as), will be passed to the assembler. The driver will recompile all source files regardless of whether they have changed since the last build. IDEs, such as MPLAB IDE, and make utilities must be employed to achieve incremental builds, if desired. See also Section 2.3.3 “Multi-step Compila- tion”. Unless otherwise specified, a HEX file and Microchip COFF file are produced as the final output. All intermediate files remain after compilation has completed, but most other temporary files are deleted, unless you use the --NODEL option (see Section 2.7.39 “--NODEL: Do not remove temporary files”) which preserves all generated files except the run-time start-up file. Note that some generated files may be in a different directory to your project source files. See Section 2.7.43 “--OUTDIR: Specify a directory for output files” and Section 2.7.41 “--OBJDIR: Specify a directory for intermediate files” which can both control the destination for some output files. 2.3.3 Multi-step Compilation Make utilities and IDEs, such as MPLAB IDE, allow for an incremental build of projects that contain multiple source files. When building a project, they take note of which source files have changed since the last build and use this information to speed up compilation. For example, if compiling two source files, but only one has changed since the last build, the intermediate file corresponding to the unchanged source file need not be regenerated. The Universal Toolsuite plugin that integrates the compiler into MPLAB IDE is aware of the different compilation sequence employed by PICC and takes care of this for you. From MPLAB IDE you can select an incremental build (Project->Build), or fully rebuild a project (Project->Rebuild). If the compiler is being invoked using a make utility, the make file will need to be configured to recognized the different intermediate file format and the options used to generate the intermediate files. Make utilities typically call the compiler multiple times: once for each source file to generate an intermediate file, and once to perform the second stage compilation. You may also wish to generate intermediate files to construct your own library files, although PICC is capable of constructing libraries in a single step, so this is typically not necessary. See Section 2.7.44 “--OUTPUT= type: Specify Output File Type” for more information on library creation. The option --PASS1 (Section 2.7.45 “--PASS1: Compile to P-code”) is used to tell the compiler that compilation should stop after the parser has executed. This will leave the p-code intermediate file behind on successful completion. For example, the files main.c and io.c are to be compiled using a make utility. The command lines that the make utility should use to compile these files might be something like: PICC --chip=16F877A --pass1 main.c PICC --chip=16F877A --pass1 io.c PICC --chip=16F877A main.p1 io.p1 If is important to note that the code generator needs to compile all p-code or p-code library files associated with the project in the one step. When using the --PASS1 option the code generator is not being invoked, so the above command lines do not violate this requirement. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 14  2010 Microchip Technology Inc. Using object files as the intermediate file format with HI-TECH C Compiler for PIC10/12/16 MCUs will defeat many features the compiler uses to optimize code. Always use p-code files as the intermediate file format if you are using a make system to build projects. 2.3.4 Compilation of Assembly Source Since the code generator performs many tasks that were traditionally performed by the linker, there could be complications when assembly source is present in a project. Assembly files are traditionally processed after C code, but it is necessary to have this performed first so that specific information contained in the assembly code can be conveyed to the code generator. The specific information passed to the code generator is discussed in more detail in Section 3.13.4 “Interaction between Assembly and C Code”. When assembly source is present, the order of compilation is as shown in Figure 2-4. FIGURE 2-4: COMPILATION SEQUENCE WITH ASSEMBLY FILES Any assembly source files are first assembled to form object files. These files, along with any other objects files that are part of the project, are then scanned by the command-line driver and information is then passed to the code generator when it subsequently builds the C files, as has been described earlier. 2.3.4.1 INTERMEDIATE FILES AND ASSEMBLY SOURCE The intermediate file format associated with assembly source files is the same as that used in traditional compilers, i.e. an object file (.obj extension). Assembly files are never passed to the code generator and so the code generator technology does not alter the way these files are compiled. The -C option (see Section 2.7.1 “-C: Compile to Object File”) is used to generate object files and halt compilation after the assembly step. 2.3.5 Printf check An extra execution of the code generator is performed prior to the actual code generation phase. This pass is part of the process by which the printf library function is customized, see Section 3.12.1 “The printf Routine” for more details. This pass is only associated with scanning the C source code for printf placeholder usage and you will see the code generator being executed if you select the verbose option when you build, see Section 2.7.15 “-V: Verbose Compile”. C file C file library files preprocess & parse p- code code generation assemble preprocess & parse p- code ASM file OBJ file link assemble driver PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 15 2.4 RUNTIME FILES In addition to the C and assembly source files specified on the command line, there are also compiler-generated source files and pre-compiled library files which might be compiled into the project by the driver. These files contain: • C Standard library routines • Implicitly called arithmetic routines • User-defined library routines • The runtime startup code • The powerup routine • The printf routine. Strictly speaking, the power-up routine is neither a compiler-generated source, nor a library routine. It is fully defined by the user, however as it is very closely associated with the runtime startup module, it is discussed with the other runtime files in the following sections. 2.4.1 Library Files The names of the C standard library files appropriate for the selected target device, and other driver options, are determined by the driver and passed to the code generator and linker. P-code libraries (.lpp libraries) are used by the code generator, and object code libraries (.lib files) are used by the linker. Most library routines are derived from p-code libraries. By default, PICC will search the lib directory under the compiler installation directory for library files that are required during compilation. 2.4.1.1 STANDARD LIBRARIES The C standard libraries contain a standardized collection of functions, such as string, math and input/output routines. The range of these functions are described in Chapter 7. “Library Functions”. Although it is considered a library function, the printf function’s code is not found in these library files. C source code for this function is generated from a special C template file that is customized after analysis of the user’s C code. See Section “PRINTF, VPRINTF” for more information on using the printf library function and Section 3.12.1 “The printf Routine” for information on how the printf function is customized when you build a project. These libraries also contain C routines that are implicitly called by the output code of the code generator. These are routines that perform tasks such as floating-point operations, integer division and type conversions, and that may not directly correspond to a C function call in the source code. The general form of the standard library names is htpic -dc.ext. The meaning of each field is described by: • The processor type is always pic. • The double type, d, is "-"for 24-bit doubles, and "d" for 32-bit doubles. • Library Type is always "c". • The extension is .lpp for p-code libraries, or .lib for relocatable object libraries. 2.4.1.2 USER-DEFINED LIBRARIES User-defined libraries may be created and linked in with programs as required. Library files are more easy to manage and may result in faster compilation times, but must be compatible with the target device and options for a particular project. Several versions of a library may need to be created to allow it to be used for different projects. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 16  2010 Microchip Technology Inc. Libraries can be created manually using the compiler and the librarian, LIBR. See Section 6.2 “Librarian” for more information on the librarian and creating library files using this application. Alternatively, library files can be created directly from the compiler by specifying a library output using the --OUTPUT option, see Section 2.7.44 “--OUTPUT= type: Specify Output File Type”. User-created libraries that should be searched when building a project can be listed on the command line along with the source files. As with Standard C library functions, any functions contained in user-defined libraries should have a declaration added to a header file. It is common practice to create one or more header files that are packaged with the library file. These header files can then be included into source code when required. Library files specified on the command line are scanned first for unresolved symbols, so these files may redefine anything that is defined in the C standard libraries. See also Section 3.16.1 “Replacing Library Modules”. 2.4.2 Runtime Startup Code A C program requires certain objects to be initialized and the processor to be in a particular state before it can begin execution of its function main(). It is the job of the runtime startup code to perform these tasks. Section Section 3.11.1 “Runtime Startup Code” details specifically what actions are taken by this code and how it interacts with programs you write. Rather than the traditional method of linking in a generic, precompiled routine, the HI-TECH C Compiler for PIC10/12/16 MCUs uses a more efficient method which actually determines what runtime startup code is required from the user’s program. Both the driver and code generator are involved in generating the runtime startup code. The driver takes care of device setup and this code is placed into a separate assembly startup module. The code generator handles initialization of the C environment, such as clearing uninitialized C variables and copying initialized C variables. This code is output along with the rest of the C program. The runtime startup code is generated automatically every time you build a project. The file created by the driver may be deleted after compilation and this operation can be controlled with the keep suboption to the --RUNTIME option. The default operation of the driver is to keep the start up module; however, if using MPLAB IDE to build, it uses options that will delete the file unless you indicate otherwise in the Build Options dialog. If the startup module is kept, it will be called startup.as and will be located in the current working directory. If you are using an IDE to perform the compilation the destination directory may be dictated by the IDE itself. Generation of the runtime startup code is an automatic process which does not require any user interaction; however, some aspects of the runtime code can be controlled, if required, using the --RUNTIME option. Section 2.7.50 “--RUNTIME: Specify Runtime Environment” describes the use of this option. See Section 3.11.1 “Runtime Startup Code” which describes the functional aspects of the code contained in this module and its effect on program operation. The runtime startup code is executed before main(), but If you require any special initialization to be performed immediately after reset, you should use power-up feature described later in Section 3.11.2 “The Powerup Routine”. 2.5 COMPILER OUTPUT There are many files created by the compiler during the compilation. A large number of these are intermediate files and some are deleted after compilation is complete, but many remain and are used for programming the device, or for debugging purposes. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 17 2.5.1 Output Files The names of many output files use the same base name as the source file from which they were derived. For example the source file input.c will create a p-code file called input.p1. Some of the output files contain project-wide information and are not directly associated with any one particular input file, e.g. the map file. If the names of these output files are not specified by a compiler option, their base name is derived from the first C source file listed on the command line. If there are no files of this type specified, the name is based on the first input file (regardless of type) on the command line. If you are using an IDE, such as MPLAB IDE, to specify options to the compiler, there is typically a project file that is created for each application. The name of this project is used as the base name for project-wide output files, unless otherwise specified by the user. However check the manual for the IDE you are using for more details. The compiler is able to directly produce a number of the output file formats which are used by PIC10/12/16 development tools. The default behavior of PICC is to produce a Microchip format COFF and Intel HEX output. Unless changed by a driver option, the base names of these files will be the project name. The default output file types can be controlled by compiler options, e.g. the --OUTPUT option. The extensions used by these files are fixed and are listed together with this option’s description in Section 2.7.44 “--OUTPUT= type: Specify Output File Type”. The COFF file is used by debuggers to obtain debugging information about the project. Table 2-13 shows all output format options available with PICC using the --OUTPUT option. The File Type column lists the filename extension which will be used for the output file. 2.5.1.1 SYMBOL FILES PICC creates two symbol files which are used to generate the debug output files, such as COFF and ELF files. These are the SYM files (.sym extension) produced by the linker, and the SDB file (.sdb extension) produced by the code generator. The SDB file contains type information, and the SYM file contains address information.These two files, in addition to the HEX file, are combined by the CROMWELL application (see Section 6.5 “Cromwell”) to produce the output debug files, such as the COFF file. 2.5.2 Diagnostic Files Two valuable files produced by the compiler are the assembly list file, produced by the assembler, and the map file, produced by the linker. The compiler options --ASMLIST (Section 2.7.17 “--ASMLIST: Generate Assembler List Files”) generates a list file, and the -M option (Section 2.7.8 “-M: Generate Map File”) specifies generation of a map file. The assembly list file contains the mapping between the original source code and the generated assembly code. It is useful for information such as how C source was encoded, or how assembly source may have been optimized. It is essential when confirming if compiler-produced code that accesses objects is atomic, and shows the psects in which all objects and code are placed. See Section 4.4 “Assembly List Files” for more information on the contents of this file. Note: Throughout this manual, the term project name will refer to either the name of the project created in the IDE, or the base name (file name without extension) of the first C source file specified on the command line. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 18  2010 Microchip Technology Inc. There is one list file produced for the entire C program, including C library files, and which will be assigned the project name and extension .lst. One additional list file is produced for each assembly source file compiled in the project. The map file shows information relating to where objects were positioned in memory. It is useful for confirming if user-defined linker options were correctly processed, and for determining the exact placement of objects and functions. It also shows all the unused memory areas in a device and memory fragmentation. See Section 5.4 “Map Files” for complete information on the contents of this file. There is one map file produced when you build a project, assuming the linker was executed and ran to completion. The file will be assigned the project name and .map extension. 2.6 COMPILER MESSAGES All compiler applications, including the command-line driver, PICC, use textual messages to report feedback during the compilation process. A centralized messaging system is used to produce the messages, which allows consistency during all stages of the compilation process. 2.6.1 Messaging Overview A message is referenced by a unique number which is passed to the messaging system by the compiler application that needs to convey the information. The message string corresponding to this number is obtained from Message Description Files (MDF), which are stored in the dat directory in the compiler’s installation directory. When a message is requested by a compiler application, its number is looked up in the MDF that corresponds to the currently selected language. The language of messages can be altered as discussed in Section 2.6.2 “Message Language”. Once found, the alert system can read the message type and the string to be displayed from the MDF. There are several different message types which are described in Section 2.6.3 “Message Type” and the type can be overridden by the user, as described in the same section. The user is also able to set a threshold for warning message importance, so that only those which the user considers significant will be displayed. In addition, messages with a particular number can be disabled. A pragma can also be used to disable a particular message number within specific lines of code. These methods are explained in Section 2.6.5.1 “Disabling Messages”. Provided the message is enabled and it is not a warning message whose level is below the current warning threshold, the message string will be displayed. In addition to the actual message string, there are several other pieces of information that may be displayed, such as the message number, the name of the file for which the message is applicable, the file’s line number and the application that issued the message, etc. If a message is an error, a counter is incremented. After a certain number of errors has been reached, compilation of the current module will cease. The default number of errors that will cause this termination can be adjusted by using the --ERRORS option, see Section 2.7.28 “--ERRORS: Maximum Number of Errors”. This counter is reset for each internal compiler application, thus specifying a maximum of five errors will allow up to five errors from the parser, five from the code generator, five from the linker, five from the driver, etc. Although the information in the MDF can be modified with any text editor, this is not recommended. Message behavior should only be altered using the options and pragmas described in the following sections. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 19 2.6.2 Message Language PICC supports more than one language for displayed messages. There is one MDF for each language supported. Under Windows, the default language can be specified when installing the compiler. The default language may be changed on the command line using the --LANG option, see Section 2.7.34 “--LANG: Specify the Language for Messages”. Alternatively, it may be changed permanently by using the --LANG option together with the --SETUP option which will store the default language in either the registry, under Windows, or in the XML configuration file on other systems. On subsequent builds, the default language used will be that specified. Table 2-3 shows the MDF applicable for the currently supported languages. If a language other than English is selected, and the message cannot be found in the appropriate non-English MDF, the alert system tries to find the message in the English MDF. If an English message string is not present, a message similar to: error/warning (*) generated, but no description available where * indicates the message number that was generated that will be printed; otherwise, the message in the requested language will be displayed. 2.6.3 Message Type There are four types of messages. These are described below along with the compiler’s behavior when encountering a message of each type. Advisory Messages convey information regarding a situation the compiler has encountered or some action the compiler is about to take. The information is being displayed “for your interest” and typically requires no action to be taken. Compilation will continue as normal after such a message is issued. Warning Messages indicate source code or some other situation that can be compiled, but is unusual and may lead to a runtime failure of the code. The code or situation that triggered the warning should be investigated; however, compilation of the current module will continue, as will compilation of any remaining modules. Error Messages indicate source code that is illegal or that compilation of this code cannot take place. Compilation will be attempted for the remaining source code in the current module, but no additional modules will be compiled and the compilation process will then conclude. Fatal Error Messages indicate a situation that cannot allow compilation to proceed and which requires the compilation process to stop immediately. 2.6.4 Message Format By default, messages are printed in a human-readable format. This format can vary from one compiler application to another, since each application reports information about different file formats. TABLE 2-3: SUPPORTED LANGUAGES Language MDF name English en_msgs.txt German de_msgs.txt French fr_msgs.txt HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 20  2010 Microchip Technology Inc. Some applications, for example the parser, are typically able to pinpoint the area of interest down to a position on a particular line of C source code, whereas other applications, such as the linker, can at best only indicate a module name and record number, which is less directly associated with any particular line of code. Some messages relate to issues in driver options which are in no way associated with any source code. There are several ways of changing the format in which message are displayed, which are discussed below. The driver option -E (with or without a filename) alters the format of all displayed messages. See Section 2.7.3 “-E: Redirect Compiler Errors to a File”. Using this option produces messages that are better suited to machine parsing, and are less user-friendly. Typically each message is displayed on a single line. The general form of messages produced when using the -E option is: filename line: (message number) message string (type) The -E option also has another effect. When used, the driver first checks to see if special environment variables have been set. If so, the format dictated by these variables are used as a template for all messages produced by all compiler applications. The names of these environment variables are given in Table 2-4. The value of these environment variables are strings that are used as templates for the message format. Printf-like placeholders can be placed within the string to allow the message format to be customized. The placeholders and what they represent are indicated in Table 2-5. If these options are used in a DOS batch file, two percent characters will need to be used to specify the placeholders, as DOS interprets a single percent character as an argument and will not pass this on to the compiler. For example: SET HTC_ERR_FORMAT=”file %%f: line %%l” Environment variables, in turn, may be overridden by the driver options: --MSGFORMAT, --WARNFORMAT and --ERRFORMAT, see Section 2.7.27 “--ERRFORMAT: Define Format for Compiler Messages”. These options take a string as their argument. The option strings are formatted, and can use the same placeholders, as their variable counterparts. For example, a project is compiled, but, as shown, produces a warning from the parser and an error from the linker (numbered 362 and 492, respectively). main.c: main() 17: ip = &b; ^ (362) redundant "&" applied to array (warning) TABLE 2-4: MESSAGING ENVIRONMENT VARIABLES Variable Effect HTC_MSG_FORMAT All advisory messages HTC_WARN_FORMAT All warning messages HTC_ERR_FORMAT All error and fatal error messages TABLE 2-5: MESSAGING PLACEHOLDERS Placeholder Replacement %a Application name %c Column number %f Filename %l Line number %n Message number %s Message string (from MDF) PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 21 (492) attempt to position absolute psect "text" is illegal Notice that the parser message format identifies the particular line and position of the offending source code. If the -E option is now used and the compiler issues the same messages, the compiler will output: main.c: 12: (362) redundant "&" applied to array (warning) (492) attempt to position absolute psect "text" is illegal (error) The user now uses the --WARNFORMAT in the following fashion: --WARNFORMAT="%a %n %l %f %s" When recompiled, the following output will be displayed: parser 362 12 main.c redundant "&" applied to array (492) attempt to position absolute psect "text" is illegal (error) Notice that the format of the warning was changed, but that of the error message was not. The warning format now follows the specification of the environment variable. The application name (parser) was substituted for the %a placeholder, the message number (362) substituted the %n placeholder, etc. 2.6.5 Changing Message Behavior Both the attributes of individual messages and general settings for the messaging system can be modified during compilation. There are both driver options and C pragmas that can be used to achieve this. 2.6.5.1 DISABLING MESSAGES Each warning message has a default number indicating a level of importance. This number is specified in the MDF and ranges from -9 to 9. The higher the number, the more important the warning. Warning messages can be disabled by adjusting the warning level threshold using the --WARN driver option, see Section 2.7.59 “--WARN: Set Warning Level”. Any warnings whose level is below that of the current threshold are not displayed. The default threshold is 0 which implies that only warnings with a warning level of 0 or higher will be displayed by default. The information in this option is propagated to all compiler applications, so its effect will be observed during all stages of the compilation process. Warnings may also be disabled by using the --MSGDISABLE option, see Section 2.7.37 “--MSGDISABLE: Disable Warning Messages”. This option takes a comma-separated list of message numbers. Those warnings listed are disabled and will never be issued, regardless of the current warning level threshold. Some warning messages can also be disabled by using the warning pragma. This pragma will only affect warnings that are produced by either the parser or the code generator, i.e. errors directly associated with C code. See Section 3.15.3.8 “The #pragma warning Directive” for more information on this pragma. Error messages can also be disabled; however, a more verbose form of the command is required to confirm the action. To specify an error message number in the --MSGDISABLE command, the number must be followed by :off to ensure that it is disabled. For example: --MSGDISABLE=195:off will disable error number 195. Note: Disabling error or warning messages in no way fixes the condition which triggered the message. Always use extreme caution when exercising these options. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 22  2010 Microchip Technology Inc. 2.6.5.2 CHANGING MESSAGE TYPES It is also possible to change the type of some messages. This can only be done for messages generated by the parser or code generator. See Section 3.15.3.8 “The #pragma warning Directive” for more information on this pragma. 2.7 PICC DRIVER OPTION DESCRIPTIONS Most aspects of the compilation can be controlled using the command-line driver, PICC. The driver will configure and execute all required applications, such as the code generator, assembler and linker. PICC recognizes the compiler options which are tabled below and explained in detail in the following sections. The case of the options is not important, however command shells in most operating systems are case sensitive when it comes to names of files. TABLE 2-6: DRIVER OPTIONS Option Meaning -C Compile to object file and stop -Dmacro Define preprocessor macro symbol -Efilename Redirect compile errors -G[filename] Generate symbolic debug information -Ipath Specify include path -Largument Set linker option -M[filename] Generate map file -Nnumber Specify identifier length -Ofile Specify output filename and type -P Preprocess assembly source -Q Quiet mode -S Compile to assembly file and stop -Umacro Undefine preprocessor macro symbol -V Verbose mode -X Strip local symbols --ADDRQUAL=qualifier Specify address space qualifier handling --ASMLIST Generate assembly list file --CHAR=type Default character type (defunct) --CHECKSUM=specification Calculate a checksum and store the result in program memory --CHIP=device Select target device --CHIPINFO Print device information --CODEOFFSET=value Specify ROM offset address --CR=file Generate cross reference file --DEBUGGER=type Set debugger environment --DOUBLE=size Size of double type --ECHO Echo command line --ERRFORMAT=format Set error format --ERRORS=number Set maximum number of errors --FILL=specification Specify a ROM-fill value for unused memory --FLOAT=size Size of float type --GETOPTION=argument Get advanced options --HELP=option Help PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 23 2.7.0.1 OPTION FORMATS All single letter options are identified by a leading dash character, “-”, e.g. -C. Some single letter options specify an additional data field which follows the option name immediately and without any whitespace, e.g. -Ddebug. In this manual, options are written in upper case and suboptions are in lower case. Multi-letter, or word, options have two leading dash characters, e.g. --ASMLIST. (Because of the double dash, the driver can determine that the option --DOUBLE, for example, is not a -D option followed by the argument OUBLE.) Some of these word options use suboptions which typically appear as a comma-separated list following an equal character, =, e.g. --OUTPUT=hex,cof. The exact format of the options varies and are described in detail in the following sections. Some commonly used suboptions include default, which represent the default specification that would be used if this option was absent altogether; all, which indicates that all the available suboptions should be enabled as if they had each been listed; and none, which indicates that all suboptions should be disabled. For example: --OPT=none --IDE=name Set development environment --LANG=language Specify language --MEMMAP=type Display memory map --MODE=mode Choose operating mode --MSGDISABLE=list Disable warning messages --MSGFORMAT=specification Set advisory message format --NODEL Do not remove temporary files --NOEXEC Do not execute compiler applications --OBJDIR=path Set object files directory --OPT=optimizations Control optimization --OUTDIR=path Set output directory --OUTPUT=path Set output formats --PASS1 Produce HI-TECH intermediate p-code file and stop --PRE Produce preprocessed source files and stop --PROTO Generate function prototypes --RAM=ranges Adjust RAM ranges --ROM=ranges Adjust ROM ranges --RUNTIME=options Specify runtime options --SCANDEP Scan for dependencies --SERIAL=specification Insert a hexadecimal code or serial number --SETOPTION=argument Set advanced options --SETUP=specification Setup the compiler --SHROUD Shroud (obfuscate) generated p-code files --STRICT Use strict ANSI keywords --SUMMARY=type Summary options --TIME Report compilation times --VER Show version information --WARN=number Set warning threshold level --WARNFORMAT=specifica- tion Set warning format TABLE 2-6: DRIVER OPTIONS (CONTINUED) Option Meaning HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 24  2010 Microchip Technology Inc. will turn off all optimizers. Some suboptions may be prefixed with a plus character, +, to indicate that they are in addition to the other suboptions present, or a minus character “-”, to indicate that they should be excluded. For example: --OPT=default,-asm indicates that the default optimization be used, but that the assembler optimizer should be disabled. If the first character after the equal sign is + or -, then the default keyword is implied. For example: --OPT=-asm is the same as the previous example. See the –-HELP option, Section 2.7.32 “--HELP: Display Help”, for more information about options and suboptions. 2.7.1 -C: Compile to Object File The -C option is used to halt compilation after executing the assembler, leaving a relocatable object file as the output. It is frequently used when compiling assembly source files using a make utility. See Section 2.3.3 “Multi-step Compilation” for more information on generating and using intermediate files. 2.7.2 -D: Define Macro The -D option is used to define a preprocessor macro on the command line, exactly as if it had been defined using a #define directive in the source code. This option may take one of two forms, -Dmacro which is equivalent to: #define macro 1 placed at the top of each module compiled using this option, or -Dmacro= text which is equivalent to: #define macro text where text is the textual substitution required. Thus, the command: PICC --CHIP=16F877AA -Ddebug -Dbuffers=10 test.c will compile test.c with macros defined exactly as if the C source code had included the directives: #define debug 1 #define buffers 10 Defining macros as C string literals requires bypassing any interpretation issues in the operating system that is being used. To pass the C string, "hello world", (including the quote characters) in the Windows environment, use: "-DMY_STRING=\\\"hello world\\\"" (you must include the quote characters around the entire option as there is a space character in the macro definition). Under Linux or Mac OS X, use: -DMY_STRING=\"hello\ world\". See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.3 -E: Redirect Compiler Errors to a File This option has two purposes. The first is to change the format of displayed messages. The second is to optionally allow messages to be directed to a file as some editors do not allow the standard command line redirection facilities to be used when invoking the compiler. The general form of messages produced with the -E option in force is: PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 25 filename line_number: (message number) message string (type) If a filename is specified immediately after -E, it is treated as the name of a file to which all messages (errors, warnings etc) will be printed. For example, to compile x.c and redirect all errors to x.err, use the command: PICC --CHIP=16F877AA -Ex.err x.c The -E option also allows errors to be appended to an existing file by specifying an addition character, +, at the start of the error filename, for example: PICC --CHIP=16F877AA -E+x.err y.c If you wish to compile several files and combine all of the errors generated into a single text file, use the -E option to create the file then use -E+ when compiling all the other source files. For example, to compile a number of files with all errors combined into a file called project.err, you could use the - E option as follows: PICC --CHIP=16F877AA -Eproject.err -O --PASS1 main.c PICC --CHIP=16F877AA -E+project.err -O --PASS1 part1.c PICC --CHIP=16F877AA -E+project.err -C asmcode.as Section 2.6 “Compiler Messages” has more information regarding this option as well as an overview of the messaging system and other related driver options. 2.7.4 -G: Generate Source-level Symbol File The -G option allows specification of the filename used for the source-level symbol file (.sym extension) for use with supported debuggers and simulators such as MPLAB IDE. See also Section 2.5 “Compiler Output”. If no filename is given, the symbol file will have the project name (see Section 2.2 “Invoking the Compiler”), and an extension of .sym. For example, the option -Gtest.sym generates a symbol file called test.sym. Symbol files generated using the -G option include source-level information for use with source-level debug- gers. 2.7.5 -I: Include Search Path Use -I to specify an additional directory to search for header files which have been included using the #include directive. The directory can either be an absolute or relative path. The -I option can be used more than once if multiple directories are to be searched. The compiler’s include directory containing all standard header files is always searched, even if no -I option is present. If header filenames are specified using quote characters rather than angle brackets, as in #include "lcd.h", then the current working directory is searched in addition to the compiler’s include directory. Note that if compiling within MPLAB IDE, the search path is relative to the output directory, not the project directory. These default search paths are searched after any user-specified directories have been searched. For example: PICC --CHIP=16F877AA -C -Ic:\include -Id:\myapp\include test.c will search the directories c:\include and d:\myapp\include for any header files included into the source code, then search the default include directory. This option has no effect for files that are included into assembly source using the assembly INCLUDE directive. See Section 4.3.10.3 “INCLUDE”. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 26  2010 Microchip Technology Inc. 2.7.6 -L: Scan Library The -L option is used to specify additional libraries which are to be scanned by the linker. Libraries specified using the -L option are scanned before the standard C library, allowing additional versions of standard library functions to be accessed. The argument to -L is a library keyword to which the prefix pic ; numbers representing the processor range, number of ROM pages and the number of RAM banks; and the suffix .lib are added. Thus the option -Ll when compiling for a 16F877A will, for example, scan the library pic42c-l.lib and the option -Lxx will scan a library called pic42c-xx.lib. All libraries must be located in the lib directory of the compiler installation directory. As indicated, the argument to the -L option is not a complete library filename. If you wish the linker to scan libraries whose names do not follow the above naming convention or whose locations are not in the lib subdirectory, simply include the libraries’ names on the command line along with your source files, or add these to your project. 2.7.7 -L-: Adjust Linker Options Directly The -L driver option can be used to specify an option which will be passed directly to the linker. If -L is followed immediately by text starting with a dash character “-”, the text will be passed directly to the linker without being interpreted by PICC. If the -L option is not followed immediately by a dash character, it is assumed the option is the library scan option, Section 2.7.6 “-L: Scan Library”. For example, if the option -L-N is specified, the -N option will be passed on to the linker without any subsequent interpretation by the driver. The linker will then process this option, when, and if, it is invoked, and perform the appropriate operation. Take care with command-line options. The linker cannot interpret command-line driver options; similarly the driver cannot interpret linker options. In most situations, it is always the command-line driver, PICC, that is being executed. If you need to add alternate linker settings in the Linker tab in the Project>MPLAB Build options... dialogue, you must add driver options (not linker options). These driver options will be used by the driver to generate the appropriate linker options during the linking process. The -L option is a means of allowing a linker option to be specified via a driver option. The -L option is especially useful when linking code which contains non-standard program sections (or psects), as may be the case if the program contains hand-written assembly code which contains user-defined psects (see 4.3.9.3 “PSECT”), or C code which uses the #pragma psect directive (see 3.15.3.5 “The #pragma psect Directive”). Without this -L option, it would be necessary to invoke the linker manually to allow the linker options to be adjusted. This option can also be used to replace default linker options. If the string starting from the first character after the -L up to the first equal character, "=", matches a psect or class name in the default options, then (the reference to the psect or class name in the default option, and the remainder of that option, are deleted) that default linker option is replaced by the option specified by the -L. For example, if a default linker option was: -preset_vec=00h,intentry,init,end_init the driver option -L-pinit=100h would result in the following options being passed to the linker: -pinit=100h -preset_vec=00h. Note the end_init linker option has been removed entirely. If there are no characters following the first equal character in the -L option, then no replacement will be made for the default linker options that will be deleted. For example, the driver option -L-pinit= will adjust the default options passed to the linker, as above, but the -pinit linker option would be removed entirely. No warning is generated if such a default linker option cannot be found. The default option that you are deleting or replacing must contain an equal character. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 27 2.7.8 -M: Generate Map File The -M option is used to request the generation of a map file. The map file is generated by the linker and includes detailed information about where objects are located in memory. See Section 5.4 “Map Files” for information regarding the content of these files. If no filename is specified with the option, then the name of the map file will have the project name (see Section 2.3 “The Compilation Sequence”), with the extension .map. This option is on by default when compiling from within MPLAB IDE and using the HI-TECH Universal Toolsuite. 2.7.9 -N: Identifier Length This option allows the C identifier length to be increased from the default value of 31. Valid sizes for this option are from 32 to 255. The option has no effect for all other val- ues. This option also controls the length of identifiers used by the preprocessor, such as macro names. The default length is also 31, and can be adjusted to a maximum of 255. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.10 -O: Specify Output File This option allows the basename of the output file(s) to be specified. If no -O option is given, the base name of output file(s) will be the same as the project name, see Section 2.3 “The Compilation Sequence”. The files whose names are affected by this option are those files that are not directly associated with any particular source file, such as the HEX file, MAP file and SYM file. The -O option can also change the directory in which the output file is located by including the required path before the filename. This will then also specify the output directory for any files produced by the linker or subsequently run applications. Any relative paths specified are with respect to the current working directory. For example, if the option -Oc:\project\output\first is used, the MAP and HEX file, etc., will use the base name first, and will be placed in the directory c:\project\output. Any extension supplied with the filename will be ignored. The options that specify MAP file creation (-M, see Section 2.7.8 “-M: Generate Map File”), and SYM file creation (-G, see Section 2.7.4 “-G: Generate Source-level Symbol File”) override any name or path information provided by -O relevant to the MAP and SYM file. To change the directory in which all output and intermediate files are written, use the --OUTDIR option, see Section Section 2.7.43 “--OUTDIR: Specify a directory for output files”. Note that if -O specifies a path which is inconsistent with the path specified in the --OUTDIR option, this will result in an error. 2.7.11 -P: Preprocess Assembly Files The -P option causes assembler source files to be preprocessed before they are assembled, thus allowing the use of preprocessor directives, such as #include, and C-style comments with assembler code. By default, assembler files are not preprocessed. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 28  2010 Microchip Technology Inc. 2.7.12 -Q: Quiet Mode This option places the compiler in a quiet mode which suppresses the Microchip Technology Incorporated copyright notice from being displayed. 2.7.13 -S: Compile to Assembler Code The -S option stops compilation after generating an assembly output file. One assembly file will be generated for all the C source code, including p-code library code. The command: PICC --CHIP=16F877A -S test.c will produce an assembly file called test.as, which contains the assembly code generated from test.c. The generated file is valid assembly code which could be passed to PICC as a source file, however this should only be done for exploratory reasons. To take advantage of the benefits of the compilation technology in the compiler, it must compile and link all the C source code in a single step. See the --PASS1 option (Section 2.7.45 “--PASS1: Compile to P-code”) to generate intermediate files if you wish to compile code using a two step process or use intermediate files. This option is useful for checking assembly code output by the compiler. The file produced by this option differs to that produced by the --ASMLIST option (see Section 2.7.17 “--ASMLIST: Generate Assembler List Files”) in that it does not contain op-codes or addresses and it may be used as a source file in subsequent compilations. The assembly list file is more human readable, but is not a valid assembly source file. 2.7.14 -U: Undefine a Macro The -U option, the inverse of the -D option, is used to undefine predefined macros. This option takes the form -Umacro, where macro is the name of the macro to be undefined The option, -Udraft, for example, is equivalent to: #undef draft placed at the top of each module compiled using this option. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.15 -V: Verbose Compile The -V option specifies verbose compilation. When used, the compiler will display the command lines used to invoke each of the compiler applications described in Section 2.3 “The Compilation Sequence”. The name of the compiler application being executed will be displayed, plus all the command-line arguments to this application. This option is useful for confirming options and files names passed to the compiler applications. If this option is used twice (-V -V), it will display the full path to each compiler application as well as the full command line arguments. This would be useful to ensure that the correct compiler installation is being executed, if there is more than one compiler installed. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 29 2.7.16 -X: Strip Local Symbols The option -X strips local symbols from any files compiled, assembled or linked. Only global symbols will remain in any object files or symbol files produced. This option is not normally required for most projects. 2.7.17 --ASMLIST: Generate Assembler List Files The --ASMLIST option tells PICC to generate assembler listing files for the C and assembly source modules being compiled. One assembly list file is produced for the entire C program, including code from the C library functions. In addition, one assembly list file is produced for each assembly source file in the project, including the runtime startup code (see Section 2.4.2 “Runtime Startup Code”). Assembly list files use a .lst extension and, due to the additional information placed in these files, cannot be used as assembly source files. In the case of listings for C source code, the list file shows both the original C code and the corresponding assembly code generated by the compiler. See Section 4.4 “Assembly List Files” for full information regarding the content of these files. The same information is shown in the list files for assembly source code. This option is on by default when compiling under MPLAB IDE and using the HI-TECH Universal Toolsuite. 2.7.18 --ADDRQUAL: Set Compiler Response to Memory Qualifiers The --ADDRQUAL option indicates the compiler’s response to non-standard memory qualifiers in C source code. By default these qualifiers are ignored, i.e. they are accepted without error, but have no effect. Using this option allows these qualifiers to be interpreted differently by the com- piler. The qualifiers affected by this option are the bankx qualifiers (bank0, bank1, bank2 etc) and near. The suboptions are detailed in Table 2-7. For example, the option: --ADDRQUAL=request 2.7.19 --CHECKSUM: Calculate a checksum The --CHECKSUM option indicates that the compiler should try to honor the bankx and near qualifiers, if present in C source code, but if they cannot be met (e.g. if near is used and there is no common memory, or a bankx qualifier is used and the indicated bank is full) then they are silently ignored. This option will perform a checksum over the address range specified and store the result at the destination address specified. Additional specifications can be appended as a comma-separated list to this option. Such specifications are: TABLE 2-7: COMPILER RESPONSES TO MEMORY QUALIFIERS Selection Response require The qualifiers will be honored. If they cannot be met, an error will be issued. request The qualifiers will be honored, if possible. No error will be generated if they cannot be followed. ignore The qualifiers will be ignored and code compiled as if they were not used. reject If the qualifiers are encountered, an error will be immediately generated. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 30  2010 Microchip Technology Inc. width=n selects the width of the checksum result in bytes. A negative width will store the result in little-endian byte order. Result widths from one to four bytes are permitted. offset=nnnn specifies an initial value or offset to be added to this checksum. algorithm=n select one of the checksum algorithms implemented in HEXMATE. The selectable algorithms are described in Table 6-9. code=nn is a hexadecimal code that will trail each byte in the checksum result. This can allow each byte of the checksum result to be embedded within an instruction. The start, end and destination attributes can be entered as word addresses as this is the native format for PICC program space. If an accompanying --FILL option has not been specified, unused locations within the specified address range will be filled with FFFh for Baseline devices, or 3FFFh for Mid-Range devices. This is to remove any unknown values from the equation and ensure the accuracy of the checksum result. For example: --checksum=800-fff@20,width=1,algorithm=8 will calculate a 1 byte checksum from address 0x800 to 0xfff and store this at address 0x20. Fletcher's algorithm will be used. See Section 6.6.1.5 “-CK”. The checksum calculations are performed by the HEXMATE application. The information in this driver option is passed to the HEXMATE application when it is executed. 2.7.20 --CHIP: Define Processor This option must be used to specify the target processor, or device, for the compilation. This is the only compiler option that is mandatory when compiling code. To see a list of supported processors that can be used with this option, use the --CHIPINFO option described in Section 2.7.21 “--CHIPINFO: Display List of Supported Processors”. 2.7.21 --CHIPINFO: Display List of Supported Processors The --CHIPINFO option displays a list of devices the compiler supports. The names listed are those chips defined in the chipinfo file and which may be used with the --CHIP option. Compilation will terminate after this list has been printed. 2.7.22 --CODEOFFSET: Offset Program Code to Address In some circumstances, such as bootloaders, it is necessary to shift the program image to an alternative address. This option is used to specify a base address for the program code image and to reserve memory from address 0 to that specified in the option. When using this option, all code psects (including reset and interrupt vectors and constant data) will be adjusted to the address specified. The address is assumed to be a hexadecimal constant. A leading 0x, or a trailing h hexadecimal specifier can be used, but is not necessary. This option differs from the --ROM option in that it will move the code associated with the reset and interrupt vectors which cannot be done using the --ROM option, see Section 2.7.49 “--ROM: Adjust ROM Ranges”. For example, if the option --CODEOFFSET=600 is specified, the reset vector will be moved from address 0 to address 600h; the interrupt vector will be moved from address 4 to 604h. No code will be placed between address 0 and 600h. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 31 See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.23 --CR: Generate Cross Reference Listing The --CR option will produce a cross reference listing. If the file argument is omitted, the raw cross reference information will be left in a temporary cross reference file, leaving the user to run the CREF utility. If a filename is supplied, for example --CR=test.crf, PICC will invoke CREF to process the cross reference information into the listing file, in this case test.crf. If multiple source files are to be included in the cross reference listing, all must be compiled and linked with the one PICC command. For example, to generate a cross reference listing which includes the source modules main.c, module1.c and nvram.c, compile and link using the command: PICC --CHIP=16F877AA --CR=main.crf main.c module1.c nvram.c Thus, this option cannot be used when using any compilation process that compiles each source file separately using the -C or --PASS1 options. Such is the case for most IDEs, including MPLAB IDE, and make utilities. See Section 6.4 “Cref” for information on the CREF utility. 2.7.24 --DEBUGGER: Select Debugger Type This option is intended for use for compatibility with development tools which can act as a debugger. PICC supports several debuggers and using this option will configure the compiler to conform to the requirements of that selected. The possible selections for this option are defined in Table 2-8. For example: PICC --CHIP=16F877AA --DEBUGGER=icd2 main.c Choosing the correct debugger is important as they can use memory resources which might be used by the project if this option is omitted. Such a conflict would lead to runtime failure. If the debugging features of the development tool are not to be used, for example the MPLAB ICD 3 is only being used as a programmer, then the debugger option can be set to none as no memory resources will be used by the tool when operating in this way. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. TABLE 2-8: SELECTABLE DEBUGGERS Suboption Debugger selected none No debugger (default) icd or icd1 MPLAB® ICD icd2 MPLAB ICD 2 icd3 MPLAB ICD 3 pickit2 PICkit™ 2 pickit3 PICkit 3 realice MPLAB REAL ICE™ in-circuit emulator HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 32  2010 Microchip Technology Inc. 2.7.25 --DOUBLE: Select kind of Double Types This option allows the kind of double-precision floating-point types to be selected. By default the compiler will choose the truncated IEEE754 24-bit implementation for double types. With this option, this can be changed to the full 32-bit IEEE754 implemen- tation. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.26 --ECHO: Echo command line before processing Use of this option will result in the driver command line being echoed to the stdout stream before compilation commences. Each token of the command line will be printed on a separate line and will appear in the order in which they are placed on the command line. 2.7.27 --ERRFORMAT: Define Format for Compiler Messages If the --ERRFORMAT option is not used, the default behavior of the compiler is to display any errors in a “human readable” form. This standard format is perfectly acceptable to a person reading the error output, but is not generally usable with environments which support compiler error handling. This option allows the exact format of printed error messages to be specified using special placeholders embedded within a message template. See Section 2.6 “Compiler Messages” for full details of the messaging system employed by PICC, and the placeholders which can be used with this option. This section is also applicable to the --WARNFORMAT and --MSGFORMAT options, which adjust the format of warning and advisory messages, respectively. If you are compiling using MPLAB IDE, the format of the compiler messages is automatically configured to what the IDE expects. It recommended that you do not adjust the message formats if compiling using this IDE. 2.7.28 --ERRORS: Maximum Number of Errors This option sets the maximum number of errors each compiler application, as well as the driver, will display before execution is terminated. By default, up to 20 error messages will be displayed by each application. See Section 2.6 “Compiler Messages” for full details of the messaging system employed by PICC. 2.7.29 --FILL: Fill Unused Program Memory This option allows specification of a hexadecimal opcode that can be used to fill all unused program memory locations. Multi-byte codes should be entered in little endian byte order. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 33 2.7.30 --FLOAT: Select kind of Float Types This option allows the size of float types to be selected. The types available to be selected are given in Table 2-9. See also the --DOUBLE option in Section 2.7.25 “--DOUBLE: Select kind of Double Types”. 2.7.31 --GETOPTION: Get Command-line Options This option is used to retrieve the command line options which are used for named compiler application. The options are then saved into the given file. This option is not required for most projects, and is disabled when the compiler is operating in Lite mode (see Section 2.7.36 “--MODE: Choose Compiler Operating Mode”). The options take an application name and a filename to store the options, for example: --GETOPTION=hlink,options.txt 2.7.32 --HELP: Display Help This option displays information on the PICC compiler options. The option --HELP will display all options available. To find out more about a particular option, use the option’s name as a parameter. For example: PICC --help=warn will display more detailed information about the --WARN option, the available suboptions, and which suboptions are enabled by default. 2.7.33 --IDE: Specify the IDE being used This option is used to automatically configure the compiler for use by the named Integrated Development Environment (IDE). The supported IDEs are shown in Table 2-10. 2.7.34 --LANG: Specify the Language for Messages This option allows the compiler to be configured to produce error, warning and some advisory messages in languages other than English. English is the default language unless this has been changed at installation, or by the use of the --SETUP option. Some messages are only ever printed in English regardless of the language specified with this option. See Section 2.6.2 “Message Language” for more information. TABLE 2-9: FLOATING-POINT SELECTIONS Suboption Effect double Size of float matches size of double type 24 24-bit float 32 32-bit float (IEEE754) TABLE 2-10: SUPPORTED IDES Suboption IDE hitide HI-TECH’s HI-TIDE™ mplab Microchip’s MPLAB® IDE HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 34  2010 Microchip Technology Inc. Table 2-11 shows those languages currently supported. 2.7.35 --MEMMAP: Display Memory Map This option will display a memory map for the specified map file. This option is seldom required, but would be useful if the linker is being driven explicitly, i.e. instead of in the normal way through the command-line driver. This command would display the memory summary which is normally produced at the end of compilation by the driver. 2.7.36 --MODE: Choose Compiler Operating Mode This option selects the basic operating mode of the compiler. The available types are pro, std and lite. A compiler operating in PRO mode uses full optimization and produces the smallest code size. Standard mode uses limited optimizations, and LITE mode only uses a minimum optimization level and will produce relatively large code. Only those modes permitted by the compiler license status will be accepted. For example if you have purchased a Standard compiler license, that compiler may be run in Standard or Lite mode, but not the PRO mode. 2.7.37 --MSGDISABLE: Disable Warning Messages This option allows warning or advisory messages to be disabled during compilation of a project. The messagelist is a comma-separated list of warning numbers that are to be disabled. If the number of an error is specified, it will be ignored by this option. If the message list is specified as 0, then all warnings are disabled. See Section 2.6.5 “Changing Message Behavior” for other ways to disable messages. For full information on the compiler’s messaging system, see Section 2.6 “Compiler Messages”. 2.7.38 --MSGFORMAT: Set Advisory Message Format This option sets the format of advisory messages produced by the compiler. Warning and error messages are controlled separately by other options. See Section 2.7.27 “--ERRFORMAT: Define Format for Compiler Messages” and Section 2.7.60 “--WARNFORMAT: Set Warning Message Format” for information on changing the format of these sorts of messages. See Section 2.6 “Compiler Messages” for full information on the compiler’s messaging system. If you are compiling using MPLAB IDE, the format of the compiler messages is automatically configured to what the IDE expects. It recommended that you do not adjust the message formats if compiling using this IDE. 2.7.39 --NODEL: Do not remove temporary files Specifying --NODEL when building will instruct PICC not to remove the intermediate and temporary files that were created during the build process. 2.7.40 --NOEXEC: Don’t Execute Compiler The --NOEXEC option causes the compiler to assemble all the command lines for the compiler applications, but not to perform any compilation or produce any output. TABLE 2-11: SUPPORTED LANGUAGES Suboption Language en, english English fr, french, francais French de, german, deutsch German PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 35 This may be useful when used in conjunction with the -V option (Section 2.7.15 “-V: Verbose Compile”) in order to see all of the command lines the compiler uses to drive the compiler applications. 2.7.41 --OBJDIR: Specify a directory for intermediate files This option allows a directory to be nominated in PICC to locate its intermediate files. If this option is omitted, intermediate files will be created in the current working direc- tory. This option will not set the location of output files, instead use --OUTDIR. See Section 2.7.43 “--OUTDIR: Specify a directory for output files” and Section 2.7.10 “-O: Specify Output File” for more information. 2.7.42 --OPT: Invoke Compiler Optimizations The --OPT option allows control of all the compiler optimizers. If this option is not specified, or it is specified as --OPT=all, all optimizations are enabled. Optimizations may be disabled by using --OPT=none, or individual optimizers may be controlled, e.g. --OPT=asm will only enable some assembler optimizations. Table 2-12 lists the available optimization types. The optimizations that are controlled through specifying a level 1 through 9 affect optimization during the code generation stage. The level selected is commonly referred to as the global optimization level. These optimizations are primarily concerned with getting variables into registers and the value in the option indicates how hard the compiler tries to make this happen. Note that different suboptions control assembler optimizations of assembly source files and intermediate assembly files produced from C source code. The speed and space suboptions are contradictory. Space optimizations are the default. If speed and space suboptions are both specified, then speed optimizations takes precedence. These optimizations affect procedural abstraction, which is performed by the assembler, and other optimizations at the code generation stage. 2.7.43 --OUTDIR: Specify a directory for output files This option allows a directory to be nominated for PICC to locate its output files. If this option is omitted, output files will be created in the current working directory. See also Section 2.7.41 “--OBJDIR: Specify a directory for intermediate files” and Section 2.7.10 “-O: Specify Output File” for more information. 2.7.44 --OUTPUT= type: Specify Output File Type This option allows the type of the output file(s) to be specified. If no --OUTPUT option is specified, the output file’s name will be the same as the project name (see Section 2.3 “The Compilation Sequence”). TABLE 2-12: OPTIMIZATION OPTIONS Option name Function 1...9 Select global optimization level (1 through 9) asm Select optimizations of assembly code derived from C source asmfile Select optimizations of assembly source files debug Favor accurate debugging over optimization speed Favor optimizations that result in faster code space Favor optimizations that result in smaller code all Enable all compiler optimizations none Do not use any compiler optimizations HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 36  2010 Microchip Technology Inc. The available output file format are shown in Table 2-13. More than one output format may be specified by supplying a comma-separated list of tags. Not all formats are supported by Microchip development tools. Those output file types which specify library formats stop the compilation process before the final stages of compilation are executed. Hence specifying an output file format list containing, e.g. lib or all will prevent the other formats from being created. So, for example: PICC --CHIP=16F877AA --OUTPUT=lpp lcd_init.c lcd_data.c lcd_msgs.c will compile the three names files into an LPP (p-code) library. 2.7.45 --PASS1: Compile to P-code The --PASS1 option is used to generate p-code intermediate files (.p1 file) from the parser, then stop compilation. Such files need to be generated if creating p-code library files, however the compiler is able to generate library files in one step, if required. See Section 2.7.44 “--OUTPUT= type: Specify Output File Type” for specifying a library output file type.) 2.7.46 --PRE: Produce Preprocessed Source Code The --PRE option is used to generate preprocessed C source files (also called modules or translation units) with an extension .pre. This may be useful to ensure that preprocessor macros have expanded to what you think they should. Use of this option can also create C source files which do not require any separate header files. If the .pre files are renamed to .c files that can be passed to the compiler for subsequent processing. This is useful when sending files to a colleague or to obtain technical support without having to send all the header files, which may reside in many directories. If you wish to see the preprocessed source for the printf() family of functions, do not use this option. The source for this function is customized by the compiler, but only after the code generator has scanned the project for printf() usage. Thus, as the –-PRE option stops compilation after the preprocessor stage, the code generator will not execute and no printf() code will be processed. If this option is omitted, the preprocessed source for printf() will be automatically retained in the file doprnt.pre. TABLE 2-13: OUTPUT FILE FORMATS Type tag File format lib Object library file lpp P-code library file intel Intel HEX tek Tektronic aahex American Automation symbolic HEX file mot Motorola S19 HEX file ubrof UBROF format bin Binary file mcof Microchip COFF cof Common Object File Format cod Bytecraft COD file format elf ELF/DWARF file format (not supported by HI-TECH C Compiler for PIC10/12/16 MCUs) PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 37 2.7.47 --PROTO: Generate Prototypes The --PROTO option is used to generate .pro files containing both ANSI C and K&R style function declarations for all functions within the specified source files. Each .pro file produced will have the same base name as the corresponding source file. Prototype files contain both ANSI C-style prototypes and old-style C function declarations within conditional compilation blocks. The extern declarations from each .pro file should be edited into a global header file, which can then be included into all the C source files in the project. The .pro files may also contain static declarations for functions which are local to a source file. These static declarations should be edited into the start of the source file. To demonstrate the operation of the --PROTO option, enter the following source code as file test.c: #include add(arg1, arg2) int * arg1; int * arg2; { return *arg1 + *arg2; } void printlist(int * list, int count) { while (count--) printf("d " *list++); putchar(’\n’); } If compiled with the command: PICC --CHIP=16F877AA --PROTO test.c PICC will produce test.pro containing the following declarations which may then be edited as necessary: /* Prototypes from test.c */ /* extern functions - include these in a header file */ #if PROTOTYPES extern int add(int *, int *); extern void printlist(int *, int); #else /* PROTOTYPES */ extern int add(); extern void printlist(); #endif /* PROTOTYPES */ 2.7.48 --RAM: Adjust RAM Ranges This option is used to adjust the default RAM, which is specified for the target device. The default memory will include all the on-chip RAM specified for the target PIC10/12/16 device, thus this option only needs be used if there are special memory requirements. Typically this option is used to reserve memory (reduce the amount of memory available). Specifying additional memory that is not in the target device will typically result in a successful compilation, but may lead to code failures at runtime. The default RAM memory for each target device is specified in the chipinfo file, PICC.INI. Strictly speaking, this option specifies the areas of memory that may be used by writable (RAM-based) objects, and not necessarily those areas of memory which contain physical RAM. The output that will be placed in the ranges specified by this option are typically variables that a program defines. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 38  2010 Microchip Technology Inc. For example, to specify an additional range of memory to that already present on-chip, use: --RAM=default,+100-1ff This will add the range from 100h to 1ffh to the on-chip memory. To only use an external range and ignore any on-chip memory, use: --RAM=0-ff This option may also be used to reserve memory ranges already defined as on-chip memory in the chipinfo file. To do this, supply a range prefixed with a minus character, -, for example: --RAM=default,-100-103 will use all the defined on-chip memory, but not use the addresses in the range from 100h to 103h for allocation of RAM objects. This option will adjust the memory ranges used by linker classes, see Section 5.2.1 “-Aclass =low-high,...”, and hence any object which is in a psect is placed in this class. Any objects contained in a psect that are explicitly placed at a memory address by the linker (see Section 5.2.18 “-Pspec”) i.e., are not placed into a memory class, are not affected by the option. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.49 --ROM: Adjust ROM Ranges This option is used to change the default ROM which is specified for the target device. The default memory will include all the on-chip ROM specified for the target PIC10/12/16 device, thus this option only needs to be used if there are special memory requirements. Typically this option is used to reserve memory (reduce the amount of memory available). Specifying additional memory that is not in the target device will typically result in a successful compilation, but may lead to code failures at runtime. The default ROM memory for each target device is specified in the chipinfo file, PICC.INI. Strictly speaking, this option specifies the areas of memory that may be used by read-only (ROM-based) objects, and not necessarily those areas of memory which contain physical ROM. When producing code that may be downloaded into a system via a bootloader, the destination memory may be some sort of (volatile) RAM. The output that will be placed in the ranges specified by this option are typically executable code and any data variables that are qualified as const. For example, to specify an additional range of memory to that on-chip, use: --ROM=default,+100-2ff This will add the range from 100h to 2ffh to the on-chip memory. To only use an external range and ignore any on-chip memory, use: --ROM=100-2ff This option may also be used to reserve memory ranges already defined as on-chip memory in the chip configuration file. To do this supply a range prefixed with a minus character, -, for example: --ROM=default,-100-1ff will use all the defined on-chip memory, but not use the addresses in the range from 100h to 1ffh for allocation of ROM objects. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 39 This option will adjust the memory ranges used by linker classes, see Section 5.2.1 “-Aclass =low-high,...”, and hence any object which is in a psect placed in this class. Any objects which are contained in a psect that are explicitly placed at a memory address by the linker (see Section 5.2.18 “-Pspec”), i.e., are not placed into a memory class, are not affected by the option. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.50 --RUNTIME: Specify Runtime Environment The --RUNTIME option is used to control what is included as part of the runtime environment. The runtime environment encapsulates any code that is present at runtime which has not been defined by the user, instead supplied by the compiler, typically as library code or compiler-generated source files. All required runtime features are enabled by default and this option is not required for normal compilation. Note that the code that clears or initializes variables, which is included by default, will clobber the contents of the STATUS register. If you need to check the cause of reset using the TO or PD bits in this register, then you must enable the resetbits suboption as well. See 3.11.1.3 “STATUS Register Preservation” for how this feature is used. The usable suboptions include those shown in Table 2-14. TABLE 2-14: RUNTIME ENVIRONMENT SUBOPTIONS Suboption Controls On (+) Implies init The code present in the main program module that copies the ROM-image of initial values to RAM variables. The ROM image is copied into RAM and initialized variables will contain their initial value at main(). clib The inclusion of library files into the output code by the linker. Library files are linked into the output. clear The code present in the main program module that clears uninitialized variables. Uninitialized variables are cleared and will contain 0 at main(). download Conditioning of the Intel HEX file for use with bootloaders. Data records in the Intel HEX file are padded out to 16 byte lengths and will align on 16 byte boundaries. Startup code will not assume reset values in certain registers. osccal Initialize the oscillator with the oscillator constant. Oscillator will be calibrated. oscval:value Set the internal clock oscillator calibration value. Oscillator will be calibrated with value supplied. keep Whether the start-up module source file is deleted after compilation. The start-up module and main program are not deleted. resetbits Preserve Power-down and Time-out STATUS bits at start up. STATUS bits are preserved. stackcall Allow function calls to use a table look-up method once the hardware stack has filled. Functions called via CALL instruction while stack not exhausted, then called via a look-up table. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 40  2010 Microchip Technology Inc. 2.7.51 --SCANDEP: Scan for Dependencies When this option is used, a .dep (dependency) file is generated. The dependency file lists those files on which the source file is dependant. Dependencies result when one file is #included into another. 2.7.52 --SERIAL: Store a Value at this Program Memory Address This option allows a hexadecimal code to be stored at a particular address in program memory. A typical task for this option might be to position a serial number in program memory. The byte-width of data to store is determined by the byte-width of the hexcode parameter in the option. For example, to store a one byte value, 0, at program memory address 1000h, use --SERIAL=00@1000. To store the same value as a four byte quantity use --SERIAL=00000000@1000. This option is functionally identical to the corresponding HEXMATE option. For more detailed information and advanced controls that can be used with this option, refer to Section 6.6.1.15 “-SERIAL”. The driver will also define a label at the location where the value was stored, and which can be referenced from C code as _serial0. To enable access to this symbol, remember to declare it, for example: extern const int _serial0; See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.53 --SETOPTION: Set The Command-line Options for Application This option is used to supply alternative command line options for the named application when compiling. The general form of this option is: --SETOPTION=app,file where the app component specifies the application that will receive the new options, and the file component specifies the name of the file that contains the additional options that will be passed to the application. This option is not required for most projects. If specifying more than one option to a component, each option must be entered on a new line in the option file. This option can also be used to remove an application from the build sequence. If the file parameter is specified as off, execution of the named application will be skipped. In most cases, this is not desirable as almost all applications are critical to the success of the build process. Disabling a critical application will result in catastrophic failure. However, it is permissible to skip a non-critical application such as CLIST or HEXMATE if the final results are not reliant on their function. 2.7.54 --SHROUD: Obfuscate p-code Files This option should be used in situations where either p-code files or p-code libraries are to be distributed and are built from confidential source code. C comments, which are normally included into these files, as well as line numbers and variable name will be removed or obfuscated so that the original source code cannot be reconstructed from distributed files. 2.7.55 --STRICT: Strict ANSI Conformance The --STRICT option is used to enable strict ANSI C conformance of all special, non-standard keywords. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 41 The HI-TECH C compiler supports various special keywords (for example the persistent type qualifier). If the --STRICT option is used, these keywords are changed to include two underscore characters at the beginning of the keyword (e.g. __persistent) so as to strictly conform to the ANSI standard. Thus if you use this option, you will need to use the qualifier __persistent in your code, not persis- tent. Be warned that use of this option may cause problems with some standard header files (e.g. ) as they contain special keywords. 2.7.56 --SUMMARY: Select Memory Summary Output Type Use this option to select the type of memory summary that is displayed after compilation. By default, or if the mem suboption is selected, a memory summary is shown. This shows the total memory usage for all memory spaces. A psect summary may be shown by enabling the psect suboption. This shows individual psects, after they have been grouped by the linker, and the memory ranges they cover. Table 2-15 shows what summary types are available. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.57 --TIME: Report Time Taken for Each Phase of Build Process Adding the --TIME option when building generates a summary which shows how much time each stage of the build process took to complete. 2.7.58 --VER: Display The Compiler’s Version Information The --VER option will display what version of the compiler is running and then exit the compiler. 2.7.59 --WARN: Set Warning Level The --WARN option is used to set the compiler warning level threshold. Allowable warning levels range from -9 to 9. The warning level determines how pedantic the compiler is about dubious type conversions and constructs. Each compiler warning has a designated warning level; the higher the warning level, the more important the warning message. If the warning message’s warning level exceeds the set threshold, the warning is printed by the compiler. The default warning level threshold is 0 and will allow all normal warning messages. TABLE 2-15: MEMORY SUMMARY SUBOPTIONS Suboption Controls On (+) Implies psect Summary of psect usage. A summary of psect names and the addresses where they were linked will be shown. mem General summary of memory used. A concise summary of memory used will be shown. class Summary of class usage. A summary of all classes in each memory space will be shown. hex Summary of address used within the HEX file. A summary of addresses and HEX files which make up the final output file will be shown. file Whether summary information is shown on the screen or shown and saved to a file. Summary information will be shown on screen and saved to a file. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 42  2010 Microchip Technology Inc. Use this option with care as some warning messages indicate code that is likely to fail during execution, or compromise portability. Warning message can be individually disabled with the --MSGDISABLE option, see Section 2.7.37 “--MSGDISABLE: Disable Warning Messages”. See also Section 2.6 “Compiler Messages” for full information on the compiler’s messaging system. See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 2.7.60 --WARNFORMAT: Set Warning Message Format This option sets the format of warning messages produced by the compiler. See Section 2.7.27 “--ERRFORMAT: Define Format for Compiler Messages” for more information on this option. For full information on the compiler’s messaging system, see Section 2.6 “Compiler Messages”. If you are compiling using MPLAB IDE, the format of the compiler messages is automatically configured to what the IDE expects. It recommended that you do not adjust the message formats if compiling using this IDE. 2.8 MPLAB IDE UNIVERSAL TOOLSUITE EQUIVALENTS When compiling from within Microchip’s MPLAB IDE, it is still the compiler’s command-line driver, PICC, that is being executed and compiling the program. The HI-TECH Universal Toolsuite plugin manages the MPLAB IDE Build Options dialog that is used to access the compiler options, and most of these graphical controls ultimately adjust the driver’s command-line options. You can see the command-line options being used when building in the Output window in MPLAB IDE. The following dialogs and descriptions identify the mapping between the dialog controls and command-line options. As the toolsuite is universal across all HI-TECH compilers, not all options are applicable for the HI-TECH C Compiler for PIC10/12/16 MCUs. 2.8.1 Directories Tab The options in this dialog control the output and search directories for some files. See Figure 2-5 in conjunction with the following command line option equivalents. PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 43 FIGURE 2-5: THE DIRECTORIES TAB 1. The output directory: This selection uses the buttons and fields grouped in the bracket to specify an output directory for files output by the compiler. This selection is handled internally by MPLAB IDE and does not use a driver option; however, it is functionally equivalent to the --OUTDIR driver option (see Section 2.7.43 “--OUTDIR: Specify a directory for output files”). 2. Include Search path: This selection uses the buttons and fields grouped in the bracket to specify include (header) file search directories. See Section 2.7.5 “-I: Include Search Path”. 2.8.2 Compiler Tab The options in this dialog control the aspects of compilation up to code generation. See Figure 2-6 in conjunction with the following command line option equivalents. 1. Define macros: The buttons and fields grouped in the bracket can be used to define preprocessor macros. See Section 2.7.2 “-D: Define Macro”. 2. Undefine macros: The buttons and fields grouped in the bracket can be used to undefine preprocessor macros. See Section 2.7.14 “-U: Undefine a Macro”. 3. Preprocess assembly: This checkbox controls whether assembly source files are scanned by the preprocessor. See Section 2.7.11 “-P: Preprocess Assembly Files”. 1 2 HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 44  2010 Microchip Technology Inc. FIGURE 2-6: THE COMPILER TAB 4. Optimization settings: These controls are used to adjust the different optimizations the compiler employs. See Section 2.7.42 “--OPT: Invoke Compiler Opti- mizations”. 5. Identifier length: This selector controls the maximum identifier length in C source. See Section 2.7.9 “-N: Identifier Length”. 6. Verbose: This checkbox controls whether the full command-lines for the compiler applications are displayed when building. See Section 2.7.15 “-V: Verbose Compile”. 7. Warning level: This selector allows the warning level print threshold to be set. See Section 2.7.59 “--WARN: Set Warning Level”. 8. Operation Mode: This selector allows the user to force another available operating mode (e.g. Lite, Standard or PRO) other than the default. See Section 2.7.36 “--MODE: Choose Compiler Operating Mode” 9. Address Qualifier: This selector allows the user to select the behavior of the address qualifier. See Section 2.7.18 “--ADDRQUAL: Set Compiler Response to Memory Qualifiers” 2.8.3 Linker Tab The options in this dialog control the link step of compilation. See Figure 2-7 in conjunction with the following command line option equivalents. 2 3 4 5 6 7 1 8 9 PICC Command-line Driver  2010 Microchip Technology Inc. DS51865B-page 45 FIGURE 2-7: THE LINKER TAB 1. Runtime options: These checkboxes control the many runtime features the compiler can employ. See Section 2.7.50 “--RUNTIME: Specify Runtime Environ- ment”. 2. Fill: This field allows a fill value to be specified for unused memory locations. See Section 2.7.29 “--FILL: Fill Unused Program Memory”. 3. Codeoffset: This field allows an offset for the program to be specified. See Section 2.7.22 “--CODEOFFSET: Offset Program Code to Address”. 4. Checksum: This field allows the checksum specification to be specified. See Section 2.7.19 “--CHECKSUM: Calculate a checksum”. 5. Errata: Not applicable. 6. Vectors: Not applicable. 7. Callgraph: Not applicable. 8. Debugger: This selector allows the type of hardware debugger to be chosen. See Section 2.7.24 “--DEBUGGER: Select Debugger Type”. 9. Trace type: Not yet implemented. 10. Stack size: Not applicable. 11. Heap size: Not applicable. 12. Frequency: Not applicable. 13. Extend address 0 in HEX file: This option specifies that the intel HEX file should have initialization to zero of the upper address. See Section 2.7.44 “--OUTPUT= type: Specify Output File Type”. 14. Interrupt options: Not applicable. 15. Summary Options: These checkboxes control which summaries are printed after compilation. See Section 2.7.56 “--SUMMARY: Select Memory Summary 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 46  2010 Microchip Technology Inc. Output Type”. 2.8.4 Global Tab The options in this dialog control aspects of compilation that are applicable throughout code generation and link steps — the second stage of compilation. See Figure 2-8 in conjunction with the following command line option equivalents. FIGURE 2-8: THE GLOBAL TAB 1. Memory model: Not applicable. 2. Double float: This selector allows the size of the double type to be selected. See Section 2.7.25 “--DOUBLE: Select kind of Double Types”. 3. Printf: Not applicable. 4. Use strict calls: Not applicable. 5. RAM ranges: This field allows the default RAM (data space) memory used to be adjusted. See Section 2.7.48 “--RAM: Adjust RAM Ranges”. 6. Code pointer size: Not applicable. 7. External memory: Not applicable. 8. Instruction set: Not applicable. 9. ROM ranges: This field allows the default ROM (program space) memory used to be adjusted. See Section 2.7.49 “--ROM: Adjust ROM Ranges”. 1 2 3 4 5 6 7 8 9 HI-TECH C® FOR PIC10/12/16 USER’S GUIDE  2010 Microchip Technology Inc. DS51865B-page 47 Chapter 3. C Language Features 3.1 INTRODUCTION HI-TECH C Compiler for PIC10/12/16 MCUs supports a number of special features and extensions to the C language which are designed to ease the task of producing ROM-based applications. This chapter documents the special language features which are specific to these devices. 3.2 ANSI C STANDARD ISSUES This compiler conforms to the ISO/IEC 9899:1990 Standard for programming languages. This is commonly called the C90 Standard. It is referred to as the ANSI C Standard in this manual. Some violations to the ANSI C Standard are indicated below in Section 3.2.1 “Divergence from the ANSI C Standard”. Some features from the later standard C99 are also supported. 3.2.1 Divergence from the ANSI C Standard HI-TECH C diverges from the ANSI C Standard in one area: function recursion. Due to limited memory and no hardware implementation of a data stack, recursion is not supported and functions are not reentrant. 3.2.2 Implementation-defined behavior Certain features of the ANSI C standard have implementation-defined behavior. This means that the exact behavior of some C code can vary from compiler to compiler. The exact behavior of the HI-TECH C compiler is detailed throughout this manual, and is fully summarized in Appendix A. “Implementation-Defined Behavior”. 3.3 PROCESSOR-RELATED FEATURES HI-TECH C has several features which relate directly to the PIC10/12/16 architectures and instruction sets. These detailed in the following sections. 3.3.1 Device Support HI-TECH C Compiler for PIC10/12/16 MCUs aims to support all Baseline and Mid-Range devices. However, new devices in these families are frequently released. There are several ways you can check if the compiler you are using supports a particular device. From MPLAB IDE, open the Build Options dialog. Select the Driver tab. In the Available Drivers field, select the compiler you wish to use. A list of all devices supported by that compiler will be shown in the Selected Driver Information and Supported Device area, towards the center of the dialog. See Figure 3-1 for the relevant fields in this dialog. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 48  2010 Microchip Technology Inc. FIGURE 3-1: SHOWING SUPPORTED DEVICES From the command line, the same information can be obtained. Run the compiler you wish to use and pass it the option --CHIPINFO (See Section 2.7.21 “--CHIPINFO: Display List of Supported Processors”). A list of all devices will be printed. 3.3.2 Device Header Files There is one header file that is recommended be included into each source file you write. The file is and is a generic file that will include other device- and chip-specific header files when you build your project. Inclusion of this file will allow access to SFRs via special variables, as well as macros which allow special memory access or inclusion of special instructions, like CLRWDT. 3.3.3 Stack The hardware stack on PIC® devices is limited in depth and cannot be manipulated directly. It is only used for function return address and cannot be used for program data. The compiler implements a compiled stack for local data objects, see Section 3.5.4 “Absolute Variables” for information on how this is achieved. You must ensure that the maximum stack depth is not exceeded; otherwise, code may fail. Calling too many nested functions may overflow the stack, and it is important to take into account interrupts, which also use levels of the stack. A call graph is provided by the code generator in the assembler list file. This will indicate the stack levels at each function call and can be used as a guide to stack depth. The code generator may also produce warnings if the maximum stack depth is exceeded. Both of these are guides to stack usage. Optimizations and the use of interrupts can decrease or increase, respectively, the stack depth used by a program over that determined by the compiler. C Language Features  2010 Microchip Technology Inc. DS51865B-page 49 3.3.4 Configuration Bit Access The PIC device processor’s configuration bits may be set using the __CONFIG() macro as follows: __CONFIG(x); Note there are two leading underscore characters. The macro is defined in the header file, so be sure to include this into the files that use this macro. The x argument is the value that is to be programmed in the configuration word. The value can either be a literal or be built up from specially named quantities that are defined in the header file appropriate for the processor you are using. These macro names are similar to the names as used in the PIC10/12/16 data sheets to represent the configuration conditions and must be bitwise ANDed together to form the configuration value. Refer to your processor’s header file for details. For example: #include __CONFIG(WDTDIS & HS & UNPROTECT); For devices that have more than one configuration word location, each subsequent invocation of __CONFIG() will modify the next configuration word in sequence. Typically this might look like: #include __CONFIG(WDTDIS & XT & UNPROTECT); // Program config. word 1 __CONFIG(FCMEN); // Program config. word 2 MPLAB IDE has a dialog (Config>Configuration bits...) which also allows configuration bits to be specified when the device is programmed. If the checkbox Configuration Bits Set in Code in this dialog is checked, any configuration bits specified in your code using the __CONFIG macro are ignored and those in the dialog used instead. Ensure the source of the configuration bit settings is known when working with an MPLAB IDE proj- ect. 3.3.5 Using SFRs From C Code The Special Function Registers (SFRs) are registers which control aspects of the MCU operation or that of peripheral modules on the device. Most of these registers are memory mapped, which means that they appear at specific addresses in the data memory space of the device. With some registers, the bits within the register control independent features. Some registers are read-only; some are write-only. Memory-mapped SFRs are accessed by special C variables that are placed at the addresses of the registers. Variables that are placed at specific addresses are called absolute variables and are described in Section 3.5.4 “Absolute Variables”. These variables can be accessed like any ordinary C variable so that no special syntax is required to access SFRs, Bit variables, as well as structures (with bit-fields), can also be made absolute and so either can be used to represent bits within the register. The SFR variables are predefined in header files and will be accessible once the header file (see Section 3.3.2 “Device Header Files”) has been included into your source code. Both bit variables and structures with bit-fields are defined by the inclusion of this header file so you may use either in your source code. The names given to the C variables, which map over the registers and bit variables, or bit-fields, within the registers are based on the names specified in the device data sheet. However, as there can be duplication of some bit names within registers, there may be differences in the nomenclature. The names of the structures that hold the bit-fields will typically be those of the corresponding register followed by bits. For example, the following shows code that includes the generic header file, clears PORTA as a whole, sets bit 0 of PORTA using a bit variable and sets bit 2 of PORTA using the structure/bit-field definitions. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 50  2010 Microchip Technology Inc. #include void main(void) { PORTA = 0x00; RA0 = 1; PORTAbits.RA2 = 1; } To confirm the names that are relevant for the device you are using, check the device specific header file that will include for the definitions of each variable. These files will be located in the include directory of the compiler and will have a name that represents the device. There is a one-to-one correlation between device and header file name that will be included by , e.g. when compiling for a PIC16LF1826 device the header file will include . Remember that you do not need to include this chip-specific file into your source code; it is automatically included by . Some SFRs are not memory mapped, do not have a corresponding variable defined in the device specific header file, and cannot be directly accessed from C code. For example, the W register is not memory mapped on Baseline devices. The older PIC16C5X devices use OPTION and TRIS registers, which are only accessible via special instructions and which are also not memory mapped. See Section 3.3.9 “Baseline PIC MCU Special Instructions” on how these registers are accessed by the compiler. Care should be taken when accessing some SFRs from C code or from assembly in-line with C code. Some registers are used by the compiler to hold intermediate values of calculations, and writing to these registers directly can result in code failure. The compiler does not detect when SFRs have changed as a result of C or assembly code that writes to then directly. The list of registers used by the compiler and further information can be found in Section 3.7 “Register Usage”. SFRs associated with peripherals are not used by the compiler to hold intermediate results and can be changed as you require. Always ensure that you confirm the operation of peripheral modules from the device data sheet. 3.3.6 ID Locations Some PIC10/12/16 devices have locations outside the addressable memory area that can be used for storing program information, such as an ID number. The __IDLOC() macro may be used to place data into these locations. The macro is used in a manner similar to: #include __IDLOC(x); where x is a list of nibbles which are positioned into the ID locations. Only the lower four bits of each ID location is programmed, so the following: __IDLOC(15F0); will attempt to fill ID locations with the values: 1, 5, F and 0. The base address of the ID locations is specified by the idloc psect which will be automatically assigned as appropriate address based on the type of device selected. Some devices will permit programming up to seven bits within each ID location. To program the full seven bits, the regular __IDLOC() macro is not suitable. For this situation, the __IDLOC7(a,b,c,d) macro is available. The parameters a to d are the values to be programmed. The values can be entered in either decimal or hexadecimal format, such as: __IDLOC7(0x7f,1,70,0x5a); C Language Features  2010 Microchip Technology Inc. DS51865B-page 51 It is not appropriate to use the __IDLOC7() macro on a device that does not permit seven bit programming of ID locations. 3.3.7 Bit Instructions Wherever possible, the HI-TECH C compiler will attempt to use the PIC10/12/16 bit instructions. For example, when using a bitwise operator and a mask to alter a bit within an integral type, the compiler will check the mask value to determine if a bit instruction can achieve the same functionality. unsigned int foo; foo |= 0x40; will produce the instruction: BSF _foo,6 To set or clear individual bits within integral type, the following macros could be used: #define bitset(var, bitno) ((var) |= 1UL << (bitno)) #define bitclr(var, bitno) ((var) &= ~(1UL << (bitno))) To perform the same operation as above, the bitset macro could be employed as follows: bitset(foo,6); 3.3.8 EEPROM Access For most devices that come with on-chip EEPROM, the compiler offers several methods of accessing this memory. The EEPROM access methods are described in the following sections. 3.3.8.1 THE __EEPROM_DATA() MACRO For those PIC10/12/16 devices that support external programming of their EEPROM data area, the __EEPROM_DATA() macro can be used to place the initial EEPROM data values into the HEX file ready for programming. The macro is used as follows. #include __EEPROM_DATA(0, 1, 2, 3, 4, 5, 6, 7); The macro accepts eight parameters, being eight data values. Each value should be a byte in size. Unused values should be specified as a parameter of zero. The macro may be called multiple times to define the required amount of EEPROM data. It is recommended that the macro be placed outside any function definitions. The macro defines, and places the data within, a psect called eeprom_data. This psect is automatically positioned by the linker. This macro is not used to write to EEPROM locations during runtime; it is used for pre-loading EEPROM contents at program time only. 3.3.8.2 EEPROM ACCESS FUNCTIONS The library functions eeprom_read() and eeprom_write(), can be called to read from, and write to, the EEPROM during program execution. For example, to write a byte-size value to an address in EEPROM and retrieve it using these functions would be: #include void eetest(void) { unsigned char value = 1; unsigned char address = 0; // write value to EEPROM address eeprom_write(address, value); HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 52  2010 Microchip Technology Inc. // read from EEPROM at address value = eeprom_read(address); } These functions test and wait for any concurrent writes to EEPROM to conclude before performing the required operation. The eeprom_write() function will initiate the process of writing to EEPROM and this process will not have completed by the time that eeprom_write() returns. The new data written to EEPROM will become valid approximately four milliseconds later. In the above example, the new value will not yet be ready at the time when eeprom_read() is called; however, because this function waits for any concurrent writes to complete before initiating the read, the correct value will be read. It may also be convenient to use the preprocessor symbol, _EEPROMSIZE, in conjunction with some of these access methods. This symbol defines the number of EEPROM bytes available for the selected chip. 3.3.8.3 EEPROM ACCESS MACROS Although these macros perform much the same service as their library function counterparts, these should only be employed in specific circumstances. It is appropriate to select EEPROM_READ or EEPROM_WRITE in favor of the library equivalents if any of the following conditions are true: • You cannot afford the extra level of stack depth required to make a function call • You cannot afford the added code overhead to pass parameters and perform a call/return • You cannot afford the added processor cycles to execute the function call over- head Be aware that if a program contains multiple instances of either macro, any code space saving will be negated as the full content of the macro is now duplicated in code space. In the case of EEPROM_READ(), there is another very important detail to note. Unlike eeprom_read(), this macro does not wait for any concurrent EEPROM writes to complete before proceeding to select and read EEPROM. Had the previous example used the EEPROM_READ() macro in place of eeprom_read() the operation would have failed. If it cannot be guaranteed that all writes to EEPROM have completed at the time of calling EEPROM_READ(), the appropriate flag should be polled prior to executing EEPROM_READ(). For example: #include void eetest(void){ unsigned char value = 1; unsigned char address = 0; // Initiate writing value to address EEPROM_WRITE(address,value); // wait for end-of-write before EEPROM_READ while(WR) continue; // read from EEPROM at address value = EEPROM_READ(address); } 3.3.9 Baseline PIC MCU Special Instructions The baseline (12-bit instruction word) devices have some registers which are not in the normal SFR area and cannot be accessed using an ordinary file instruction. The HI-TECH C compiler is instructed to automatically use the special instructions intended for such cases when pre-defined symbols are accessed. C Language Features  2010 Microchip Technology Inc. DS51865B-page 53 The definition of the special symbols make use of the control qualifier. This qualifier informs the compiler that the registers are outside of the normal address space and that a different access method is required. 3.3.9.1 THE OPTION INSTRUCTION Some baseline PIC devices use an OPTION instruction to load the OPTION register. The header file will ensure a special definition for a C object called OPTION, and macros for the bit symbols which are stored in this register. PICC will automatically use the OPTION instruction when an appropriate processor is selected and the OPTION register is accessed. For example, to set the prescaler assignment bit so that prescaler is assigned to the watchdog timer, the following code can be used. OPTION = PSA; This will load the appropriate value into the W register and then call the OPTION instruction. 3.3.9.2 THE TRIS INSTRUCTIONS Some PIC devices use a TRIS instruction to load the TRIS register. The header file will ensure a special definition for a C object called TRIS. PICC will automatically use the TRIS instruction when an appropriate processor is selected and the TRIS register is accessed. For example, to make all the bits on the output port high impedance, the following code can be used. TRIS = 0xFF; This will load the appropriate value into the W register and then call the TRIS instruction. Those PIC devices which have more than one output port may have definitions for objects: TRISA, TRISB and TRISC, depending on the exact number of ports available. This objects are used in the same manner as described above. 3.3.9.3 OSCILLATOR CALIBRATION CONSTANTS Some PIC devices come with an oscillator calibration constant which is pre-programmed into the device’s program memory. This constant can be read from program memory and written to the OSCCAL register to calibrate the internal RC oscillator. On some baseline PIC devices, the calibration constant is stored as a MOVLW instruction at the top of program memory, e.g. the PIC12C50X and PIC16C505 parts. On Reset, the program counter is made to point to this instruction and it is executed first before the program counter wraps around to 0x0000, which is the effective reset vector for the device. The default HI-TECH C startup routine will automatically include code to load the OSCCAL register with the value contained in the W register after reset on such devices. No other code is required. For other chips, such as PIC12C67X chips, the oscillator constant is also stored at the top of program memory, but as a RETLW instruction. The compiler’s startup code will automatically generate code to retrieve this value and perform the configuration. Loading of the calibration value can be turned off via the --RUNTIME option (see Section 2.7.50 “--RUNTIME: Specify Runtime Environment”). At runtime, this calibration value may be read using the macro _READ_OSCCAL_DATA(). To be able to use this macro, make sure that is included into the relevant modules of your program. This macro returns the calibration constant which can then be stored into the OSCCAL register, as follows: HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 54  2010 Microchip Technology Inc. OSCCAL = _READ_OSCCAL_DATA(); 3.4 SUPPORTED DATA TYPES AND VARIABLES 3.4.1 Integer Data Types The HI-TECH C compiler supports integer data types with 1, 2, 3 and 4 byte sizes as well as a single bit type. Table 3-1 shows the data types and their corresponding size and arithmetic type. The default type for each type is underlined. The bit and short long types are non-standard types available in this implementa- tion. All integer values are represented in little endian format with the Least Significant Byte at the lower address. If no signedness is specified in the type, then the type will be signed except for the char types which are always unsigned. The bit type is always unsigned and the concept of a signed bit is meaningless. Signed values are stored as a two’s complement integer value. The range of values capable of being held by these types is summarized in Table 3-2 The symbols in this table are preprocessor macros which are available after including in your source code. As the size of data types are not fully specified by the ANSI Standard, these macros allow for more portable code which can check the Note: The location which stores the calibration constant is never code protected and will be lost if you reprogram the device. Thus, if you are using a windowed or Flash device, the calibration constant must be saved from the last ROM location before it is erased. The constant must then be reprogrammed at the same location along with the new program and data. If you are using an in-circuit emulator (ICE), the location used by the calibration RETLW instruction may not be programmed. Calling the _READ_OSCCAL_DATA() macro will not work and will almost certainly not return correctly. If you wish to test code that includes this macro on an ICE, you will have to program a RETLW instruction at the appropriate location in program memory. Remember to remove this instruction when programming the actual part so you do not destroy the calibration value. TABLE 3-1: INTEGER DATA TYPES Type Size (bits) Arithmetic Type bit 1 Unsigned integer signed char 8 Signed integer unsigned char 8 Unsigned integer signed short 16 Signed integer unsigned short 16 Unsigned integer signed int 16 Signed integer unsigned int 16 Unsigned integer signed short long 24 Signed integer unsigned short long 24 Unsigned integer signed long 32 Signed integer unsigned long 32 Unsigned integer C Language Features  2010 Microchip Technology Inc. DS51865B-page 55 limits of the range of values held by the type on this implementation.The macros associated with the short long type are non-standard macros available in this implemen- tation. When specifying a signed or unsigned short int, short long int or long int type, the keyword int may be omitted. Thus a variable declared as short will contain a signed short int and a variable declared as unsigned short will contain an unsigned short int. It is a common misconception that the C char types are intended purely for ASCII character manipulation. This is not true; indeed, the C language makes no guarantee that the default character representation is even ASCII.1 The char types are simply the smallest of the multi-bit integer sizes, and behave in all respects like integers. The reason for the name “char” is historical and does not mean that char can only be used to represent characters. It is possible to freely mix char values with values of other types in C expressions. With the HI-TECH C compiler, the char types will commonly be used for a number of purposes: as 8-bit integers, as storage for ASCII characters, and for access to I/O locations. 3.4.1.1 BIT DATA TYPES AND VARIABLES The HI-TECH C Compiler for PIC10/12/16 MCUs supports bit integral types which can hold the values 0 or 1. Single bit variables may be declared using the keyword bit, for example: bit init_flag; These variables cannot be auto or parameters to a function, but can be qualified static, allowing them to be defined locally within a function. For example: int func(void) { static bit flame_on; // ... TABLE 3-2: RANGES OF INTEGER TYPE VALUES Symbol Meaning Value CHAR_BIT Bits per char 8 CHAR_MAX Max. value of a char 127 CHAR_MIN Min. value of a char -128 SCHAR_MAX Max. value of a signed char 127 SCHAR_MIN Min. value of a signed char -128 UCHAR_MAX Max. value of an unsigned char 255 SHRT_MAX Max. value of a short 32767 SHRT_MIN Min. value of a short -32768 USHRT_MAX Max. value of an unsigned short 65535 INT_MAX Max. value of an int 32767 INT_MIN Min. value of a int -32768 UINT_MAX Max. value of an unsigned int 65535 SHRTLONG_MAX Max. value of a short long 8388607 SHRTLONG_MIN Min. value of a short long -8388608 USHRTLONG_MAX Max. value of an unsigned short long 16777215 LONG_MAX Max. value of a long 2147483647 LONG_MIN Min. value of a long -2147483648 ULONG_MAX Max. value of an unsigned long 4294967295 1.This implementation does use ASCII as the character representation. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 56  2010 Microchip Technology Inc. } A function may return a bit object by using the bit keyword in the function’s prototype in the usual way. The 1 or 0 value will be returned in the carry flag in the STATUS reg- ister. The bit variables behave in most respects like normal unsigned char variables, but they may only contain the values 0 and 1, and therefore provide a convenient and efficient method of storing flags. Eight bit objects are packed into each byte of memory storage, so they don’t consume large amounts of internal RAM. Operations on bit objects are performed using the single bit instructions (bsf and bcf) wherever possible, thus the generated code to access bit objects is very effi- cient. It is not possible to declare a pointer to bit types or assign the address of a bit object to any pointer. Nor is it possible to statically initialize bit variables so they must be assigned any non-zero starting value (i.e. 1) in the code itself. Bit objects will be cleared on startup, unless the bit is qualified persistent. When assigning a larger integral type to a bit variable, only the Least Significant bit is used. For example, if the bit variable bitvar was assigned as in the following: int data = 0x54; bit bitvar; bitvar = data; it will be cleared by the assignment since the Least Significant bit of data is zero. This sets the bit type apart from the C99 Standard __Bool, which is a boolean type, not a 1-bit wide integer. The __Bool type is not supported on the HI-TECH C compiler. If you want to set a bit variable to be 0 or 1 depending on whether the larger integral type is zero (false) or non-zero (true), use the form: bitvar = (data != 0); The psects in which bit objects are allocated storage are declared using the bit PSECT directive flag, see Section 4.3.9.3 “PSECT”. All addresses specified for bit objects and psects will be bit addresses. Take care when comparing these addresses to byte addresses used by all other variables. If the PICC flag --STRICT is used, the bit keyword becomes unavailable. 3.4.2 Floating-Point Data Types The HI-TECH C compiler supports 24- and 32-bit floating-point types. Floating point is implemented using either a IEEE 754 32-bit format, or a modified (truncated) 24-bit form of this.Table 3-3 shows the data types and their corresponding size and arithmetic type. For both float and double values, the 24-bit format is the default. The options --FLOAT=24 and --DOUBLE=24 can also be used to specify this explicitly. The 32-bit format is used for double values if the --DOUBLE=32 option is used and for float values if --FLOAT=32 is used. Variables may be declared using the float and double keywords, respectively, to hold values of these types. Floating-point types are always signed and the unsigned keyword is illegal when specifying a floating-point type. Types declared as long douTABLE 3-3: FLOATING-POINT DATA TYPES Type Size (bits) Arithmetic Type float 24 or 32 Real double 24 or 32 Real long double same as double Real C Language Features  2010 Microchip Technology Inc. DS51865B-page 57 ble will use the same format as types declared as double. All floating-point values are represented in little endian format with the Least Significant Byte at the lower address. This format is described in Table 3-4, where: • Sign is the sign bit which indicates if the number is positive or negative • The exponent is 8 bits which is stored as excess 127 (i.e. an exponent of 0 is stored as 127). • Mantissa is the mantissa, which is to the right of the radix point. There is an implied bit to the left of the radix point which is always 1 except for a zero value, where the implied bit is zero. A zero value is indicated by a zero exponent. The value of this number is (-1)sign x 2(exponent-127) x 1. mantissa. Here are some examples of the IEEE 754 32-bit formats shown in Table 3-5. Note that the Most Significant bit of the mantissa column (i.e. the bit to the left of the radix point) is the implied bit, which is assumed to be 1 unless the exponent is zero (in which case the float is zero). The 32-bit example in Table 3-5 can be calculated manually as follows. The sign bit is zero; the biased exponent is 251, so the exponent is 251-127=124. Take the binary number to the right of the decimal point in the mantissa. Convert this to decimal and divide it by 223 where 23 is the number of bits taken up by the mantissa, to give 0.302447676659. Add 1 to this fraction. The floating-point number is then given by: -10 2124 1.302447676659 which becomes: 12.126764793256e+371.302447676659 which is approximately equal to: 2.77000e+37 Binary floating-point values are sometimes misunderstood. It is important to remember that not every floating-point value can be represented by a finite sized floating-point number. The size of the exponent in the number dictates the range of values that the number can hold, and the size of the mantissa relates to the spacing of each value that can be represented exactly. Thus the 24-bit format allows for values with approximately the same range of values, but the values that can be exactly represented by this format are more widely spaced. TABLE 3-4: FLOATING-POINT FORMATS Format Sign Biased exponent Mantissa IEEE 754 32-bit x xxxx xxxx xxx xxxx xxxx xxxx xxxx xxxx modified IEEE 754 24-bit x xxxx xxxx xxx xxxx xxxx xxxx TABLE 3-5: FLOATING-POINT FORMAT EXAMPLE IEEE 754 Format Number Biased exponent 1.mantissa Decimal 32-bit 7DA6B69Bh 11111011b 1.0100110101101101 0011011b 2.77000e+37 (251) (1.302447676659) — 24-bit 42123Ah 10000100b 1.001001000111010b 36.557 (132) (1.142395019531) — HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 58  2010 Microchip Technology Inc. So, for example, if you are using a 24-bit wide floating-point type, it can exactly store the value 95000.0. However, the next highest number it can represent is 95002.0 and it is impossible to represent any value in between these two in such a type as it will be rounded. This implies that C code which compares floating-point type may not behave as expected. For example: volatile float myFloat; myFloat = 95002.0; if(myFloat == 95001.0) // value will be rounded PORTA++; // this line will be executed! in which the result of the if() expression will be true, even though it appears the two values being compared are different. Compare this to a 32-bit floating-point type, which has a higher precision. It also can exactly store 95000.0 as a value. The next highest value which can be represented is (approximately) 95000.00781. The characteristics of the floating-point formats are summarized in Table 3-6. The symbols in this table are preprocessor macros which are available after including in your source code. Two sets of macros are available for float and double types, where XXX represents FLT and DBL, respectively. So, for example, FLT_MAX represents the maximum floating-point value of the float type. It can have two values depending on whether float is a 24 or 32 bit wide format. DBL_MAX represents the same values for the double type. As the size and format of floating-point data types are not fully specified by the ANSI Standard, these macros allow for more portable code which can check the limits of the range of values held by the type on this implementation. 3.4.3 Structures and Unions HI-TECH C Compiler for PIC10/12/16 MCUs supports struct and union types. Structures and unions only differ in the memory offset applied to each member. These types will be at least 1 byte wide. The members of structures and unions may not be objects of type bit, but bit-fields are fully supported. Structures and unions may be passed freely as function arguments and function return values. Pointers to structures and unions are fully supported. TABLE 3-6: RANGES OF FLOATING-POINT TYPE VALUES Symbol Meaning 24-bit Value 32-bit Value XXX_RADIX Radix of exponent representation 2 2 XXX_ROUNDS Rounding mode for addition 0 0 XXX_MIN_EXP Min. n such that FLT_RADIXn-1 is a normalized float value -125 -125 XXX_MIN_10_EXP Min. n such that 10n is a normalized float value -37 -37 XXX_MAX_EXP Max. n such that FLT_RADIXn-1 is a normalized float value 128 128 XXX_MAX_10_EXP Max. n such that 10n is a normalized float value 38 38 XXX_MANT_DIG Number of FLT_RADIX mantissa digits 16 24 XXX_EPSILON The smallest number which added to 1.0 does not yield 1.0 3.05176e-05 1.19209e-07 C Language Features  2010 Microchip Technology Inc. DS51865B-page 59 3.4.3.1 STRUCTURE AND UNION QUALIFIERS The HI-TECH C compiler supports the use of type qualifiers on structures. When a qualifier is applied to a structure, all of its members will inherit this qualification. In the following example the structure is qualified const. const struct { int number; int *ptr; } record = { 0x55, &i }; In this case, the entire structure will be placed into the program space and each member will be read-only. Remember that all members are usually initialized if a structure is const as they cannot be initialized at runtime. If the members of the structure were individually qualified const, but the structure was not, then the structure would be positioned into RAM, but each member would be read-only. Compare the following structure with the above. struct { const int number; int * const ptr; } record = { 0x55, &i}; 3.4.3.2 BIT-FIELDS IN STRUCTURES HI-TECH C Compiler for PIC10/12/16 MCUs fully supports bit-fields in structures. Bit-fields are always allocated within 8-bit words, even though it is usual to use the type unsigned int in the definition. The first bit defined will be the Least Significant bit of the word in which it will be stored. When a bit-field is declared, it is allocated within the current 8-bit unit if it will fit; otherwise, a new byte is allocated within the structure. Bit-fields can never cross the boundary between 8-bit allocation units. For example, the declaration: struct { unsigned lo : 1; unsigned dummy : 6; unsigned hi : 1; } foo; will produce a structure occupying 1 byte. If foo was ultimately linked at address 10H, the field lo will be bit 0 of address 10H; hi will be bit 7 of address 10H. The Least Significant bit of dummy will be bit 1 of address 10H and the Most Significant bit of dummy will be bit 6 of address 10h. Unnamed bit-fields may be declared to pad out unused space between active bits in control registers. For example, if dummy is never referenced the structure above could have been declared as: struct { unsigned lo : 1; unsigned : 6; unsigned hi : 1; } foo; A structure with bit-fields may be initialized by supplying a comma-separated list of initial values for each field. For example: struct { unsigned lo : 1; unsigned mid : 6; unsigned hi : 1; } foo = {1, 8, 0}; HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 60  2010 Microchip Technology Inc. Structures with unnamed bit fields may be initialized. No initial value should be supplied for the unnamed members, for example: struct { unsigned lo : 1; unsigned : 6; unsigned hi : 1; } foo = {1, 0}; will initialize the members lo and hi correctly. The HI-TECH C compiler supports anonymous unions. These are unions with no identifier and whose members can be accessed without referencing the enclosing union. These unions can be used when placing inside structures. For example: struct { union { int x; double y; }; } aaa; void main(void) { aaa.x = 99; // ...} Here, the union is not named and its members accessed as if they are part of the structure. Anonymous unions are not part of any C Standard and so their use limits the portability of any code. 3.4.4 Pointer Types There are two basic pointer types supported by the HI-TECH C Compiler for PIC10/12/16 MCUs: data pointers and function pointers. Data pointers hold the addresses of variables which can be indirectly read, and possible indirectly written, by the program. Function pointers hold the address of an executable function which can be called indirectly via the pointer. To conserve memory requirements and reduce execution time, pointers on PIC devices are made different sizes and formats. The HI-TECH C Compiler for PIC10/12/16 MCUs uses sophisticated algorithms to track the assignment of addresses to all pointers, and, as a result, no non-standard qualifiers are required when defining pointer variables. Despite this, the size of each pointer is optimal for its intended usage in the program. 3.4.4.1 COMBINING TYPE QUALIFIERS AND POINTERS It is helpful to first review the ANSI C standard conventions for definitions of pointer types. Pointers can be qualified like any other C object, but care must be taken when doing so as there are two quantities associated with pointers. The first is the actual pointer itself, which is treated like any ordinary C variable and has memory reserved for it. The second is the target, or targets, that the pointer references, or to which the pointer points. The general form of a pointer definition looks like the following: target_type_&_qualifiers * pointer’s_qualifiers pointer’s_name; Any qualifiers to the right of the * (i.e. next to the pointer’s name) relate to the pointer variable itself. The type and any qualifiers to the left of the * relate to the pointer’s targets. This makes sense since it is also the * operator that dereferences a pointer, which allows you to get from the pointer variable to its current target. C Language Features  2010 Microchip Technology Inc. DS51865B-page 61 Here are three examples of pointer definitions using the volatile qualifier. The fields in the definitions have been highlighted with spacing: volatile int * vip ; int * volatile ivp ; volatile int * volatile vivp ; The first example is a pointer called vip. It contains the address of int objects that are qualified volatile. The pointer itself — the variable that holds the address — is not volatile; however, the objects that are accessed when the pointer is dereferenced are treated as being volatile. In other words, the target objects accessible via the pointer may be externally modified. The second example is a pointer called ivp which also contains the address of int objects. In this example, the pointer itself is volatile, that is, the address the pointer contains may be externally modified; however, the objects that can be accessed when dereferencing the pointer are not volatile. The last example is of a pointer called vivp which is itself qualified volatile, and which also holds the address of volatile objects. Bear in mind that one pointer can be assigned the addresses of many objects; for example, a pointer that is a parameter to a function is assigned a new object address every time the function is called. The definition of the pointer must be valid for every target address assigned. 3.4.4.2 DATA POINTERS The HI-TECH C compiler monitors and records all assignments of addresses to each data pointer the program contains. This includes assignment of the addresses of objects to pointers; assignment of one pointer to another; initialization of pointers when they are defined; and takes into account when pointers are ordinary variables and function parameters, and when pointers are used to access basic objects, or structures or arrays. The size and format of the address held by each pointer is based on this information. When more than one address is assigned to a pointer at different places in the code, a set of all possible targets the pointer can address is maintained. This information is specific to each pointer defined in the program, thus two pointers with the same C type may hold addresses of different sizes and formats due to the way the pointers were used in the program. The compiler tracks the memory location of all targets, as well as the size of all targets to determine the size and scope of a pointer. The size of a target is important as well particularly with arrays of structures. A pointer must be able to be incremented to point to all the elements of an array, for example. There are several pointer classifications used with the HI-TECH C Compiler for PIC10/12/16 MCUs, such as those indicated below. • An 8-bit pointer capable of accessing common memory and two consecutive banks, e.g. banks 0 and 1, or banks 7 and 8, etc. • A 16-bit pointer capable of accessing the entire data memory space • An 8-bit pointer capable of accessing up to 256 bytes of program space data • A 16-bit pointer capable of accessing up to 64 kbytes of program space data • A 16-bit pointer capable of accessing the entire data space memory and up to 64 Note: Care must be taken when describing pointers. Is a “const pointer” a pointer that points to const objects, or a pointer that is const itself? You can talk about “pointers to const” and “const pointers” to help clarify the definition, but such terms may not be universally understood. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 62  2010 Microchip Technology Inc. kbytes of program space data Each data pointer will be allocated one of the available classifications after preliminary scans of the source code. There is no mechanism by which the programmer can specify the style of pointer required (other than by the assignments to the pointer). If the C code does not convey the required information to the compiler, then it is not complete or accurate. Information about the pointers and their targets are shown in the pointer reference graph, which is described in Section 4.4.2 “Pointer Reference Graph”. This graph is printed in the assembly list file, which is controlled by the option described in Section 2.7.17 “--ASMLIST: Generate Assembler List Files”. Consider the following program in the early stages of development. It consists of the following code: int i, j; int getValue(const int * ip) { return *ip; } void main(void) { j = getValue(&i); // ... code that uses j } A pointer, ip, is a parameter to the function getValue(). The pointer target type uses the qualifier const since we do not want the pointer to be used to write to any objects whose addresses are passed to the function. The const qualification serves no other purpose and does not alter the format of the pointer variable. If the compiler allocates the variable i (defined in main()) to bank 0 data memory, it will also be noted that the pointer ip (parameter to getValue()) only points to one object that resides in bank 0 of the data memory. In this case, the pointer, ip, is made an 8-bit wide data pointer. The generated code that dereferences ip in getValue() will be generated assuming that the address can only be to an object in bank 0. As the program is developed, another variable, x, is defined and (unknown to the programmer) is allocated space in bank 2 data memory. The main() function now looks like: int i, j; // allocated to bank 0 in this example int x; // allocated to bank 2 in this example int getValue(const int * ip) { return *ip; } void main(void) { j = getValue(&i); // ... code that uses j j = getValue(&x); // ... code that uses j } The pointer, ip, now has targets that are in bank 0 and in bank 2.To be able to accommodate this situation, the pointer is made 16 bits wide, and the code used to dereference the pointer will change accordingly. This takes place without any modification to the source code. One positive aspect of tracking pointer targets is less of a dependence on pointer qualifiers. The standard qualifiers const and volatile must still be used in pointer definitions to indicate a read-only or externally-modifiable target object, respectively. C Language Features  2010 Microchip Technology Inc. DS51865B-page 63 However this is in strict accordance with the ANSI C standard. HI-TECH specific qualifiers, like near and bankx, do not need to be used to indicate pointer targets, have no effect, and should be avoided. Omitting these qualifiers will result in more portable and readable code, and reduce the chance of extraneous warnings being issued by the compiler. 3.4.4.2.1 Pointers to Both Memory Spaces When a pointer is assigned the address of one or more objects allocated memory in the data space, and also assigned the address of one or more const objects, the pointer will be classified such that it can dereference both memory spaces, and the address will be encoded so that the target memory space can be determined at run- time. This pointer classification is considered as a “default”. If a program accesses a C pointer in assembly code, the compiler will force the those pointers to have this default classification. The encoding of this pointer type is this: the MSb of the address (i.e. bit number 15) held by such pointers indicates the memory space that the address references. If this bit is set, it indicates that the address is of something in program memory; clear indicates an object in the data memory. The remainder of this address represents the address in the indicated memory space. To extend the example given in Section 3.4.4.2 “Data Pointers” the code is now developed further, and the function getValue() is now called with the address of an object that resides in the program memory, as shown. int i, j; // allocated to bank 0 in this example int x; // allocated to bank 2 in this example const int type = 0x3456; int getValue(const int * ip) { return *ip; } void main(void) { j = getValue(&i); // ... code that uses j j = getValue(&x); // ... code that uses j j = getValue(&type); // ... code that uses j } Again, the targets to the pointer, ip, are determined and now the pointer is made of the class that can access both data and program memory. The generated code to dereference the pointer will be such that it can determine the required memory space from the address and access either space accordingly. Again, this takes place without any change in the definition of the pointer. 3.4.4.3 FUNCTION POINTERS The HI-TECH C compiler fully supports pointers to functions, which allows functions to be called indirectly. These are often used to call one of several function addresses stored in a user-defined C array, which acts like a lookup table. Function pointers are always one byte in size and hold an offset into a jump table that is output by the compiler. This jump table contains jumps to the destination functions. As with data pointers, the target assigned to function pointers is tracked. This is an easier process to undertake compared to that associated with data pointers as all function instructions must reside in program memory. The pointer reference graph (described in HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 64  2010 Microchip Technology Inc. Section 4.4.2 “Pointer Reference Graph”) will show function pointers, in addition to data pointers, as well as all their targets. The targets will be names of functions that could possibly be called via the pointer. One notable runtime feature is that if a function contains NULL (the value 0) and is used to call a function indirectly, the code will become stuck in a loop which branches to itself. This endless loop can be used to detect this erroneous situation. Typically calling a function via a NULL function would result in the code crashing or some other unexpected behavior. The label to which the endless loop will jump is called fpbase. 3.4.4.4 SPECIAL POINTER TARGETS Pointers and integers are not interchangeable. Assigning an integer constant to a pointer will generate a warning to this effect. For example: const char * cp = 0x123; // the compiler will flag this as bad code There is no information in the integer constant, 0x123, relating to the type, size or memory location of the destination. There is a very good chance of code failure if pointers are assigned integer addresses and dereferenced, particularly for devices like PIC devices which have more than one address space. Is 0x123 an address in data memory or program memory? How big is the object found at address 0x123? Always take the address of a C object when assigning an address to a pointer. If there is no C object defined at the destination address, then define or declare an object at this address which can be used for this purpose. Make sure the size of the object matches the range of the memory locations that can be accessed. For example, a checksum for 1000 memory locations starting at address 0x900 in program memory is to be generated. A pointer is used to read this data. You may be tempted to write code such as: const char * cp; cp = 0x900; // what resides at 0x900??? and increment the pointer over the data. A much better solution is this: const char * cp; const char inputData[1000] @ 0x900; cp = &inputData; // cp is incremented over inputData and used to read values there In this case, the compiler can determine the size of the target and the memory space. The array size and type indicates the size of the pointer target, the const qualifier on the object (not the pointer) indicates the target is located in program memory space. Note that the const array does not need initial values to be specified in this instance, see Section 3.4.6.1 “Const Type Qualifier” and can reside over the top of other objects at these addresses. If the pointer has to access objects in data memory, you need to define a different object to act as a dummy target. For example, if the checksum was to be calculated over 10 bytes starting at address 0x90 in data memory, the following code could be used. const char * cp; char inputData[10] @ 0x90; cp = &inputData; // cp is incremented over inputData and used to read values there User-defined absolute objects will not be cleared by the runtime startup code and can be placed over the top of other absolute variables. Take care when comparing (subtracting) pointers. For example: if(cp1 == cp2) ; take appropriate action C Language Features  2010 Microchip Technology Inc. DS51865B-page 65 The ANSI C standard only allows pointer comparisons when the two pointer targets are the same object. The address may extend to one element past the end of an array. Comparisons of pointers to integer constants are even more risky, for example: if(cp1 == 0x246) ; take appropriate action In some cases pointers hold an address offset and if the pointer can reference objects in more than one memory space, additional bits in the address will be used to distinguish which memory space is being accessed. Thus a pointer which points to an object stored at address 0x246 in data memory, may contain a different value to a pointer that points to a target located at address 0x246 in program memory. Never compare pointers and integer constants. A NULL pointer is the one instance where a constant value can be assigned to a pointer and this is handled correctly by the compiler. A NULL pointer is numerically equal to 0 (zero), but this is a special case imposed by the ANSI C standard. Comparisons with the macro NULL are also allowed. If NULL is the only value assigned to a pointer, the pointer will be made as small as possible. 3.4.5 Constant Types and Formats A constant is used to represent a numerical value in the source code, for example 123 is a constant. Like any value, a constant must have a C type. In addition to a constant’s type, the actual value can be specified in one of several formats. The format of integral constants specifies their radix. HI-TECH C supports the ANSI standard radix specifiers as well as ones which enables binary constants to be specified in C code. The formats used to specify the radices are given in Table 3-7. The letters used to specify binary or hexadecimal radices are case insensitive, as are the letters used to specify the hexadecimal digits. Any integral constant will have a type of int, long int or long long int, so that the type can hold the value without overflow. Constants specified in octal or hexadecimal may also be assigned a type of unsigned int, unsigned long int or unsigned long long int if the signed counterparts are too small to hold the value. The default types of constants may be changed by the addition of a suffix after the digits, e.g. 23U, where U is the suffix. Table 3-8 shows the possible combination of suffixes and the types that are considered when assigning a type. So, for example, if the suffix l is specified and the value is a decimal constant, the compiler will assign the type long int, if that type will hold the constant; otherwise, it will assigned long long int. If the constant was specified as an octal or hexadecimal constant, then unsigned types are also considered. TABLE 3-7: RADIX FORMATS Radix Format Example binary 0b number or 0B number 0b10011010 octal 0 number 0763 decimal number 129 hexadecimal 0x number or 0X number 0x2F HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 66  2010 Microchip Technology Inc. Here is an example of code that may fail because the default type assigned to a constant is not appropriate: unsigned long int result; unsigned char shifter; void main(void) { shifter = 20; result = 1 << shifter; // code that uses result } The constant 1 will be assigned an int type hence the result of the shift operation will be an int and the upper bits of the long variable, result, can never be set, regardless of how much the constant is shifted. In this case, the value 1 shifted left 20 bits will yield the result 0, not 0x100000. The following uses a suffix to change the type of the constant, hence ensure the shift result has an unsigned long type. result = 1UL << shifter; Floating-point constants have double type unless suffixed by f or F, in which case it is a float constant. The suffixes l or L specify a long double type which is considered an identical type to double by HI-TECH C. Character constants are enclosed by single quote characters, ’, for example ’a’. A character constant has int type, although this may be optimized to a char type later in the compilation. Multi-byte character constants are not supported by this implementation. String constants, or string literals, are enclosed by double quote characters ", for example "hello world". The type of string constants is const char * and the character that make up the string are stored in the program memory, as are all objects qualified const. Assigning a string literal to a pointer to a non-const char will generate a warning from the compiler. This code is legal, but the behavior if the pointer attempts to write to the string will fail. For example: char * cp= "one"; // "one" in ROM, produces warning const char * ccp= "two"; // "two" in ROM, correct TABLE 3-8: SUFFIXES AND ASSIGNED TYPES Suffix Decimal Octal or Hexadecimal u or U unsigned int unsigned long int unsigned long long int unsigned int unsigned long int unsigned long long int l or L long int long long int long int unsigned long int long long int unsigned long long int u or U, and l or L unsigned long int unsigned long long int unsigned long int unsigned long long int ll or LL long long int long long int unsigned long long int u or U, and ll or LL unsigned long long int unsigned long long int C Language Features  2010 Microchip Technology Inc. DS51865B-page 67 Defining and initializing a non-const array (i.e. not a pointer definition) with a string, for example: char ca[]= "two"; // "two" different to the above is a special case and produces an array in data space which is initialized at startup with the string "two" (copied from program space), whereas a string constant used in other contexts represents an unnamed const -qualified array, accessed directly in program space. The HI-TECH C compiler will use the same storage location and label for strings that have identical character sequences, except where the strings are used to initialize an array residing in the data space as shown in the last statement in the previous example. For example, in the code snippet if(strncmp(scp, "hello", 6) == 0) fred = 0; if(strcmp(scp, "world") == 0) fred--; if(strcmp(scp, "hello world") == 0) fred++; the characters in the string "world" and the last 6 characters of the string "hello world" (the last character is the nul terminator character) would be represented by the same RETLW instructions stored at the same memory locations. The string "hello" would not overlap with the same characters in the string "hello world" as they differ in terms of the placement of the nul character. Two adjacent string constants (i.e. two strings separated only by white space) are concatenated by the compiler. Thus: const char * cp = "hello" "world"; will assign the pointer with the address of the string "hello world ". 3.4.6 Standard Type Qualifiers Type qualifiers provide additional information regarding how an object may be used. The HI-TECH C compiler supports both ANSI C qualifiers and additional special qualifiers which are useful for embedded applications and which take advantage of the PIC MCU architecture. 3.4.6.1 CONST TYPE QUALIFIER The HI-TECH C compiler supports the use of the ANSI type qualifiers const and vol- atile. The const type qualifier is used to tell the compiler that an object is read only and will not be modified. If any attempt is made to modify an object declared const, the compiler will issue a warning or error. User-defined objects declared const are placed in a special psect linked into the program space. Objects qualified const may be absolute. The @ address construct is used to place the object at the specified address in program memory as in the following example which places the object tableDef at address 0x100. const int tableDef[] @ 0x100 = { 0, 1, 2, 3, 4}; Usually a const object must be initialized when it is declared, as it cannot be assigned a value at any point at runtime. For example: const int version = 3; HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 68  2010 Microchip Technology Inc. will define version as being an int variable that will be placed in the program memory, will always contain the value 3, and which can never be modified by the program. However uninitialized const objects can be defined and are useful if you need to place an object in program memory over the top of other objects at a particular location. Usually uninitialized const objects will be defined as absolute as in the following example. const char checksumRange[0x100] @ 0x800; will define the object checksumRange as a 0x100 byte array of characters located at address 0x800 in program memory. This definition will not place any data in the HEX file. 3.4.6.2 VOLATILE TYPE QUALIFIER The volatile type qualifier is used to tell the compiler that an object cannot be guaranteed to retain its value between successive accesses. This prevents the optimizer from eliminating apparently redundant references to objects declared volatile because it may alter the behavior of the program to do so. Any SFR which can be modified by hardware or which drives hardware is qualified as volatile, and any variables which may be modified by interrupt routines should use this qualifier as well. For example: volatile static unsigned int TACTL @ 0x160; The volatile qualifier does not guarantee that any access will be atomic, which is often not the case with the PIC10/12/16 architecture, which can only access a maximum of 1 byte of data per instruction. The code produced by the compiler to access volatile objects may be different to that to access ordinary variables, and typically the code will be longer and slower for volatile objects, so only use this qualifier if it is necessary. However failure to use this qualifier when it is required may lead to code failure. Another use of the volatile keyword is to prevent variables being removed if they are not used in the C source. If a non-volatile variable is never used, or used in a way that has no effect on the program’s function, then it may be removed before code is generated by the compiler. A C statement that consists only of a volatile variable’s name will produce code that reads the variable’s memory location and discards the result. For example the entire statement: PORTB; will produce assembly code the reads PORTB, but does nothing with this value. This is useful for some peripheral registers that require reading to reset the state of interrupt flags. Normally such a statement is not encoded as it has no effect. Some variables are treated as being volatile even though they may not be qualified in the source code. See Section 3.13.4.2 “Undefined Symbols” if you have assembly code in your project. 3.4.7 Special Type Qualifiers The HI-TECH C Compiler for PIC10/12/16 MCUs supports special type qualifiers to allow the user to control placement of static and extern class variables into particular address spaces. 3.4.7.1 PERSISTENT TYPE QUALIFIER By default, any C variables that are not explicitly initialized are cleared on startup. This is consistent with the definition of the C language. However, there are occasions where it is desired for some data to be preserved across a reset. C Language Features  2010 Microchip Technology Inc. DS51865B-page 69 The persistent type qualifier is used to qualify variables that should not be cleared by the runtime startup code. In addition, any persistent variables will be stored in a different area of memory to other variables. Different psects are used to hold these objects. See 3.10.1 “Compiler-generated Psects” for more information. This type qualifier may not be used on variables of class auto; however, statically defined local variables may be qualified persistent. For example, you should write: void test(void) { static persistent int intvar; /* must be static */ // ... } If the PICC option, --STRICT is used, this type qualifier is changed to __persistent. 3.4.7.2 NEAR TYPE QUALIFIER The near type qualifier can be used to place static variables in the common memory of the PIC MCU, if such memory is supported by the selected device. Some of the PIC MCU architectures implement data memory which can be always accessed regardless of the currently selected bank. This common memory can be used to reduce code size and execution times as the bank selection instructions that are normally required to access data in banked memory are not required when accessing the common memory. There are very small amounts of this memory and, if it is present at all, is often only a few bytes. The compiler automatically uses the common memory for frequently accessed user-defined variables so this qualifier would only be needed for special memory placement of objects, for example if C variables are accessed in hand-written assembly code that assumes that they are located in this memory. This qualifier is controlled by the compiler option --ADDRQUAL, which determines its effect, see Section 2.7.18 “--ADDRQUAL: Set Compiler Response to Memory Qualifiers”. Based on this option’s settings, this qualifier may be binding or ignored (which is the default operation). Qualifiers which are ignored will not produce an error or warning, but will have no effect. Here is an example of an unsigned char object qualified as near: near unsigned char fred; Objects qualified near cannot be auto or parameters to a function, but can be qualified static, allowing them to be defined locally within a function, as in: void myFunc(void) { static near unsigned char local_fred; Note that the compiler may store some temporary objects in the common memory, so not all of this space may be available for user-defined variables. If the PICC option, --STRICT is used, this type qualifier is changed to __near. 3.4.7.3 BANK0, BANK1, BANK2 AND BANK3 TYPE QUALIFIERS The bank0, bank1, bank2 and bank3 type qualifiers are recognized by the compiler and allow some degree of control of the placement of objects in the PIC MCU data memory banks. They can be used to allow portability of legacy code or to define C objects that are assumed to be located in certain memory banks by hand-written assembly code. The compiler automatically allocates variables to all data banks, so these qualifiers are not normally needed. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 70  2010 Microchip Technology Inc. These qualifiers are controlled by the compiler option --ADDRQUAL, which determines their effect, see Section 2.7.18 “--ADDRQUAL: Set Compiler Response to Memory Qualifiers”. Based on this option’s settings, these qualifiers may be binding or ignored (which is the default operation). Qualifiers which are ignored will not produce an error or warning, but will have no effect. Objects qualified with any of these qualifiers cannot be auto or parameters to a function, but can be qualified static, allowing them to be defined locally within a function, as in: void myFunc(void) { static bank1 unsigned char play_mode; If the PICC option, --STRICT is used, these qualifiers are changed to __bank0, __bank1, __bank2 and __bank3. 3.5 MEMORY ALLOCATION AND ACCESS There are two broad groups of RAM-based variables: auto/parameter variables, which are allocated to some form of stack, and global/static variables, which are positioned freely throughout the data memory space. The memory allocation of these two groups is discussed separately in the following sections. 3.5.1 Address Spaces All Baseline and Mid-Range PIC MCU devices have a Harvard architecture that has a separate data memory space (RAM) and program memory space (often flash). Some devices also implement EEPROM. The data memory uses banking to increase the amount of available memory (referred to in the data sheets as the general purpose register file) without having to increase the assembly instruction width. One bank is “selected” by setting one or more bits in an SFR. (Consult your device data sheet for the exact operation of the device you are using.) Instructions which access a data address use only the offset into the currently selected bank to access data. Some devices only have one bank but many have more than one. Both the general purpose RAM and SFRs both share the same data space and may appear in all available memory banks. Due to the presence of SFRs at the lower address of each bank, the general purpose memory becomes fragmented and this limits the size of most objects. The Enhanced Mid-Range devices overcome this limitation by allowing a linear addressing mode, which allows the general purpose memory to be accessed as one contiguous chunk. Thus, when compiling for these devices, the maximum allowable size of objects typically increases. See Section 3.5.2.3 “Auto Variable Size Limits” and Section 3.5.2.1.2 “Non-auto Variable Size Limits”. Many devices have several bytes which can be accessed regardless of which bank is currently selected. This memory is called common memory. Since no code is required to select a bank before accessing these locations, access to objects in this memory is typically faster and produces smaller code. The program memory space is primarily for executable code, but variables can also be located here. There are several ways the different device families locate and read data from this memory, but all objects located here will be read-only. 3.5.2 Variables in Data Space Memory Most variables are ultimately positioned into the data space memory. The exceptions are non-auto variables which are qualified as const, which are placed in the program memory space. C Language Features  2010 Microchip Technology Inc. DS51865B-page 71 Due to the fundamentally different way in which auto variables and non-auto variables are allocated memory, they are discussed separately. To use the C language terminology, these two groups of variables are those with automatic storage duration and those with permanent storage duration, respectively. 3.5.2.1 NON-AUTO VARIABLE ALLOCATION Non-auto variables (those with permanent storage duration) are located by the compiler into any of the available data banks. This is done in a two-stage process: placing each variable into an appropriate psect and later linking that psect into a predetermined bank. Thus, during compilation, the code generator can determine which bank will hold each variable and encode the output accordingly, but it will not know the exact location within that bank. The compiler will attempt to locate all variables in one bank (i.e. place all variables in the psect destined for this bank), but if this fills (i.e. if the compiler detects that the psect has become too large for the free space in a bank), variables will be located in other banks via different psects. Qualifiers are not required to have these variables placed in banks other than bank 0 but can be used if you want to force a variable to a particular bank. See Section 3.4.7.3 “Bank0, Bank1, Bank2 and Bank3 Type Qualifiers” and Section 2.7.18 “--ADDRQUAL: Set Compiler Response to Memory Qualifiers” for more information on how to do this. If common memory is available on the target device, this will also be considered for variables. This memory is limited in size and may be reserved for special use, so few variables can be allocated to it. The compiler considers three categories of non-auto variable, which all relate to the value the variable should contain by the time the program begins. Each variable category has a corresponding psect which is used to hold the output code which reserves memory for each variable. The basename of each psect category is tabulated below. A full list of all psect names are listed in Section 3.9 “Interrupts”. nv These psects are used to store variables qualified persistent, whose values should not be altered by the runtime startup code. They are not cleared or otherwise modified at startup. bss These psects contain any uninitialized variables, which are not assigned a value when they are defined, or variables which should be cleared by the runtime startup code. data These psects contain the RAM image of any initialized variables, which are assigned a non-zero initial value when they are defined and which must have a value copied to them by the runtime startup code. As described in Section 3.10 “Psects”, the basename of data space psects is always used in conjunction with a linker class name to indicate the RAM bank in which the psect will be positioned. This section also lists other variants of these psects and indiNote: The terms “local” and “global” are commonly used to describe variables, but are not ones defined by the language Standard. The term “local variable” is often taken to mean a variable which has scope inside a function, and “global variable” is one which has scope throughout the entire program. However, the C language has three common scopes: block, file (i.e. internal linkage) and program (i.e. external linkage), so using only two terms to describe these can be confusing. For example, a static variable defined outside a function has scope only in that file, so it is not globally accessible, but it can be accessed by more than one function inside that fie, so it is not local to any one function either. In terms of memory allocation, there are two ways this is performed and this purely relates to whether a variable is an auto or not, hence the grouping in this section. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 72  2010 Microchip Technology Inc. cates where these psect must be linked. See also Section 3.11 “Main, Runtime startup and reset” for more information on how initial values are assigned to the vari- ables. Note that the data psect used to hold initialized variables is the psect that holds the RAM variables themselves. There is a corresponding psect (called idata) that is placed into program memory (so it is non-volatile) and which is used to hold the initial values that are copied to the RAM variables by the runtime startup code. 3.5.2.1.1 Static Variables All static variables have permanent storage duration, even those defined inside a function which are “local static” variables. Local static variables only have scope in the function or block in which they are defined, but unlike auto variables, their memory is reserved for the entire duration of the program. Thus they are allocated memory like other non-auto variables. Static variables may be accessed by other functions via pointers since they have permanent duration. Variables which are static are guaranteed to retain their value between calls to a function, unless explicitly modified via a pointer. Variables which are static and which are initialized only have their initial value assigned once during the program’s execution. Thus, they may be preferable over initialized auto objects which are assigned a value every time the block in they are defined begins execution. Any initialized static variables are initialized in the same way as other non-auto initialized objects by the runtime startup code, see Section 2.4.2 “Runtime Startup Code”. Local objects which are static are assigned an assembly symbol which consists of the function name followed by an @ symbol and the variable’s lexical name, e.g. main@foobar will be the assembly identifier used for the static variable foobar defined in main(). Non-local static objects use their lexical name with a leading underscore character, e.g. _foobar will be the assembly identifier used for this object. However, if there is more than one such static object defined, then subsequent objects will use the name of the file that contains them and their lexical name separated by an @ symbol, e.g. lcd@foobar. would be the assembly symbol for the static variable foobar defined in lcd.c. 3.5.2.1.2 Non-auto Variable Size Limits Arrays of any type (including arrays of aggregate types) are fully supported by the compiler. So too are the structure and union aggregate types, see 3.4.3 “Structures and Unions”. These objects can often become large in size and may affect memory allo- cation. When compiling for enhanced Mid-Range PIC devices, the size of an object (array or aggregate object) is typically limited only by the total available data memory. Single objects that will not fit into any of the available general purpose RAM ranges will be allocated memory in several RAM banks and accessed using the device’s linear GPR (general purpose RAM). Note that the special function registers (which reside in the data memory space) or memory reservations in general purpose RAM may prevent objects from being allocated contiguous memory in the one bank. In this case objects that are smaller than the size of a RAM bank may also be allocated across multi-banks. The generated code to access multi-bank objects will always be slower and the associated code size will be larger than for objects fully contained within a single RAM bank. C Language Features  2010 Microchip Technology Inc. DS51865B-page 73 On baseline and other Mid-Range devices, arrays and structures are limited to the maximum size of the available GPR memory in each RAM bank. An error will result if an array is defined which is larger than this size. Again, memory reservations in general purpose RAM further restrict the contiguous memory in the one bank and may result in additional size limits. 3.5.2.1.3 Changing the Default Non-auto Variable Allocation There are several ways in which non-auto variables can be located in locations other than the default. Variables can be placed in other device memory spaces by the use of qualifiers. For example if you wish to place variables in the program memory space, then the const specifier should be used (see Section 3.4.6.1 “Const Type Qualifier”). If you wish to prevent all variables from using one or more data memory locations so that these locations can be used for some other purpose, you are best reserving the memory using the memory adjust options. See Section 2.7.48 “--RAM: Adjust RAM Ranges” for information on how to do this. If only a few non-auto variables are to be located at specific addresses in data space memory, then the variables can be made absolute. This allows individual variables to be explicitly positioned in memory at an absolute address. Absolute variables are described in Section 3.5.4 “Absolute Variables”. Once variables are made absolute, their address is hard coded in generated output code, they are no longer placed in a psect and do not follow the normal memory allocation procedure. The psects in which the different categories of non-auto variables (the nv, bss and data psects described in Section 3.5.2.1 “Non-auto Variable Allocation”) can be shifted as a whole by changing the default linker options. So, for example, you could move all the persistent variables. However, typically these psects can only be moved within the data bank in which they were allocated by default. See Section 3.10 “Psects” for more information on changing the default linker options for psects. The code generate makes assumptions as to the location of these psects and if you move them to a location that breaks these assumptions, code may fail. 3.5.2.2 AUTO VARIABLE ALLOCATION AND ACCESS This section discusses allocation of auto variables (those with automatic storage duration). This also include function parameter variables, which behave like auto variables, as well as temporary variables defined by the compiler. The auto (short for automatic) variables are the default type of local variable. Unless explicitly declared to be static, a local variable will be made auto. The auto keyword may be used if desired. The auto variables, as their name suggests, automatically come into existence when a function is executed, then disappear once the function returns. Since they are not in existence for the entire duration of the program, there is the possibility to reclaim memory they use when the variables are not in existence and allocate it to other variables in the program. Typically such variables are stored on some sort of a data stack, which can easily allocate then deallocate memory as required by each function. All devices targeted by the compiler do not have a data stack that can be operated in this fashion. The devices can only use their hardware stack for function return addresses and have no instructions which allow data to be placed onto this stack. The stack size is also only several words long and so it unsuitable for data of any substantial quantity. As a result, an alternative stack construct is implemented by the compiler. The stack mechanism employed is known as a compiled stack and is fully described in Section 3.5.2.2.1 “Compiled Stack Operation”. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 74  2010 Microchip Technology Inc. Once auto variables have been allocated a relative position in the compiled stack, the stack itself is then allocated memory in the data space. This is done is a similar fashion to the way non-auto variables are assigned memory: a psect is used to hold the stack and this psect is placed into the available data memory by the linker. The psect used to hold the compiled stack is called cstack, and like with non-auto variable psects, the psect basename is always used in conjunction with a linker class name to indicate the RAM bank in which the psect will be positioned. See Section 3.10.1 “Compiler-generated Psects” for the limitations associated with where this psect can be linked. The auto variables defined in a function will not necessarily be allocated memory in the order declared, in contrast to parameters which are always allocated memory based on their lexical order. In fact, auto variables for one function may be allocated in many RAM banks. The the standard qualifiers: const and volatile may both be used with auto variables and these do not affect how they are positioned in memory. This implies that a local const-qualified object is still an auto object and, as such, will be allocated memory in the compiled stack in the data space memory, not in the program memory like with non-auto const objects. The compiler will try to locate the stack in one data bank, but if this fills (i.e. if the compiler detects that the psect has become too large for the free space in a bank), it can build up the stack into several components (each with their own psect) and link each in a different bank. Each auto object is referenced in assembly code using a special symbol defined by the code generator. If accessing auto variables defined in C source code, you must use these symbols, which are discussed in Section 3.13.3.1 “Equivalent Assembly Sym- bols”. 3.5.2.2.1 Compiled Stack Operation A compiled stack consists of fixed memory areas that are usable by each function’s stack-based variables. When a compiled stack is used, functions are not re-entrant since stack-based variables in each function will use the same fixed area of memory every time the function is invoked. Fundamental to the generation of the compiled stack is the call graph, which defines a tree-like hierarchy of function calls, i.e it shows what functions may be called by each function. There will be one graph produced for each root function. A root function is typically not called, but which is executed via other means and contains a program entry point. The function main() is an example of a root function that will be in every project. Interrupt functions which are executed when a hardware interrupt occurs, are another example. C Language Features  2010 Microchip Technology Inc. DS51865B-page 75 FIGURE 3-2: FORMATION OF CALL GRAPH Figure 3-2 shows sections of a program being analyzed by the code generator to form a call graph. In the original source code, the function main() calls F1(), F2() and F3(). F1() calls F4(), but the other two functions make no calls. The call graph for main() indicates these calls. The symbols F1, F2 and F3 are all indented one level under main. F4 is indented one level under F1. This is a static call graph which shows all possible calls. If the exact code for function F1() looked like: int F1(void) { if(PORTA == 44) return F4(); return 55; } the function F4() will always appear in the call graph, even though it is conditionally executed in the actual source code. Thus, the call graph indicates all functions that might be called. In the diagram, there is also an interrupt function, isr(), and it too has a separate graph generated. The term main-line code is often used, and refers to any code that is executed as a result of the main() function being executed. In the above figure, F1(), F2(), F3() and F4() are only ever called by main-line code. The term interrupt code refers to any code that is executed as a result of an interrupt being generated, in the above figure, F5() and F6() are called by interrupt code. Figure 3-3 graphically shows an example of how the compiled stack is formed. Analysis of program main F1 F4 F2 F3 isr F5 F6 Call graph code generator main { F1(…); F2(…); F3(…); } F1 { F4(…); } isr { F5(…); F6(…); } HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 76  2010 Microchip Technology Inc. FIGURE 3-3: FORMATION OF THE COMPILED STACK Each function in the program is allocated a block of memory for its parameter, auto and temporary variables. Each block is referred to as an auto-parameter block (APB). The figure shows the APB being formed for function F2(), which has two parameters, a and b, and one auto variable, c. The parameters to the function are first grouped in an order strictly determined by the lexical order in which they appear in the source code. These are then followed by any auto objects, however the auto objects may be placed in any order. So we see memory for a is followed by that for b and lastly c. Once these variables have been grouped, the exact location of each object is not important at this point and we can represent this memory by one block — the APB for this function. The APBs are formed for all functions in the program. Then, by analyzing the call graph, these blocks are assigned positions, or bases values, in the compiled stack. Memory can be saved if the following point is observed: If two functions are never active at the same time, then their APBs can be overlapped. In the example shown in the figure, F4() and F1() are active at the same time, in fact F1() calls F4(). However F2(), F3() and F1() are never active at the same time; F1() must return before F2() or F3() can be called by main(). The function main() will always be active and so its APB can never overlap with that of an other function. In the compiled stack, you can see that the APB for main() is allocated unique memory. The blocks for F1(), F2() and F3() are all placed on top of each other and the same base value in the compiled stack, however the memory taken up by the APBs for F1() and F4() are unique and do not overlap. Our example also has an interrupt function, isr(), and its call graph is used to assemble the APBs for any interrupt code in the same way. Being the root of a graph, isr() will always be allocated unique memory, and the APBs for interrupt functions will be allocated memory following. The end result is a block of memory which forms the compiled stack. This block can then be placed into the device’s memory by the linker. F3 F6 F2 compiled stack main F1 F4 isr F5 F2(int a , int b ) { ; } F2 char c int a int b a bb c Formation of auto-parameter block (APB) for function F2 Overlap of non-concurrently active APBs to form compiled stack Analysis of call graph main F1 F4 F2 F3 isr F5 F6 1 2 3 3 2 1 F 4 F 2 6F5 C Language Features  2010 Microchip Technology Inc. DS51865B-page 77 For devices with more than one bank of data memory, the compiled stack may be built up into components, each located in a different memory bank. The compiler will try to allocate the compiled stack in one bank, but if this fills, it will consider other banks. The process of building these components of the stack is the same, but each APB will be allocated to one of the stack components based on the remaining memory in the component’s destination bank. Human readable symbols are defined by the code generator which can be used to access auto and parameter variables in the compiled stack from assembly code, if required. See Section 3.13.3.1 “Equivalent Assembly Symbols” for full information between C domain and assembly domain symbols. 3.5.2.3 Auto Variable Size Limits The compiled stack is built up as one contiguous block which can be placed into one of the available data banks. However if the stack becomes too large for this space, it can be assembled into several blocks, with each block being positioned in a different bank of memory. Thus the total size of the stack is roughly limited only by the available memory on the device. Unlike with non-auto variables, it is not efficient to access auto variables within the compiled stack using the linear memory of Enhanced Mid-Range devices. Thus, for all devices, including Enhanced Mid-Range PIC MCUs, each component of the compiled stack must fit entirely within one bank of data memory on the target device (however you can have more than one component, each allocated to a different bank). This limits the size of objects within the stack to the maximum free space of the bank in which it is allocated. The more auto variables in the stack; the more restrictive the space is to large objects. Recall that SFRs are usually present in each data bank, so the maximum amount of GPR available in each bank is typically less than the bank size. If a program requires large objects that should not be accessible to the entire program, consider leaving them as local objects, but using the static specifier. Such variables are still local to a function, but are no longer auto and have fewer size limitations. They are allocated memory as described in Section 3.5.2.1 “Non-auto Variable Alloca- tion”. 3.5.3 Variables in Program Space The only variables that are placed into program memory are those that are not auto and which have been qualified const. Any auto variables qualified const are placed in the compiled stack along with other auto variables, and all components of the compiled stack will only ever be located in the data space memory. Any const-qualified (auto or non-auto) variable will always be read-only and any attempt to write to these in your source code will result in an error being issued by the compiler. On most PIC devices, the program space is not directly readable by the device. The compiler stores data in the program memory by means of RETLW instructions which can be called, and which will return a byte if data in the W register. The compiler will generate the code necessary to make it appear that program memory is being read directly. Enhanced Mid-Range PIC devices can directly read their program memory, although the compiler will still usually store data as RETLW instructions. This way the compiler can either produce code that can call these instructions to obtain the program memory data as with the ordinary Mid-Range devices, or directly read the operand to the instruction (the Least Significant Byte of the RETLW instruction). The most efficient access method can be selected by the compiler when the data needs to be read. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 78  2010 Microchip Technology Inc. A const object is usually defined with initial values, as the program cannot write to these objects at runtime. However this is not a requirement. An uninitialized const object can be defined to define a symbol, or label, but not make a contribution to the output file. Uninitialized const objects are often made absolute, see Section 3.5.4 “Absolute Variables”. Here are examples of const object definitions. const char IOtype = ’A’; // initialized const object const char buffer[10]; // I just define a label The data held by non-auto const variables is placed in the strings psect. See Section 3.10.1 “Compiler-generated Psects” for the limitations associated with where this psect can be linked. See Section 3.13.3.1 “Equivalent Assembly Symbols” for the equivalent assembly symbols that are used to represent const-qualified variables in program memory. 3.5.3.1 SIZE LIMITATIONS OF CONST VARIABLES Arrays of any type (including arrays of aggregate types) can be qualified const and placed in the program memory. So too can structure and union aggregate types, see 3.4.3 “Structures and Unions”. These objects can often become large in size and may affect memory allocation. For Baseline PIC devices, the maximum size of a single const object is 255 bytes. However, you can define as many const objects as required provided the total size does not exceed the available program memory size of the device. Note that as well as other program code, there is also code required to be able to access const-qualified data in the program memory space. Thus, you may need additional program memory space over the size of the object itself. This additional code to access the const data is only included once, regardless of the amount or number of const-qualified objects. For Mid-Range and Enhanced Mid-Range devices, the maximum size of a const-qualified object is limited only by the available program memory. These devices also use additional code that accesses the const data, but this code is also only included once, regardless of the amount or number of const-qualified objects. 3.5.3.2 CHANGING THE DEFAULT ALLOCATION If you only intend to prevent all variables from using one or more program memory locations so that you can use those locations for some other purpose, you are best reserving the memory using the memory adjust options. See Section 2.7.49 “--ROM: Adjust ROM Ranges” for information on how to do this. If only a few non-auto const variables are to be located at specific addresses in program space memory, then the variables can be made absolute. This allows individual variables to be explicitly positioned in memory at an absolute address. Absolute variables are described in Section 3.5.4 “Absolute Variables”. Once variables are made absolute, their address is hard coded in generated output code, they are no longer placed in a psect and do not follow the normal memory allocation procedure. The psects in which the different categories of non-auto const variables (the strings and stringtext psects) can be shifted as a whole by changing the default linker options. However, there are limitations in where these psects can be moved to. See Section 3.10 “Psects” for more information on changing the default linker options for these psects. 3.5.4 Absolute Variables Most variables can be located at an absolute address by following its declaration with the construct @ address, where address is the location in memory where the variable is to be positioned. Such a variables is known as an absolute variables. C Language Features  2010 Microchip Technology Inc. DS51865B-page 79 3.5.4.1 ABSOLUTE VARIABLES IN DATA MEMORY Absolute variables are primarily intended for equating the address of a C identifier with a special function register, but can be used to place ordinary variables at an absolute address in data memory. For example: volatile unsigned char Portvar @ 0x06; will declare a variable called Portvar located at 06h in the data memory. The compiler will reserve storage for this object and will equate the variable’s identifier to that address. The compiler-generated assembler will include a line similar to: _Portvar EQU 06h No auto variables can be made absolute as they are located in a compiled stack. See Section 3.5.2.2.1 “Compiled Stack Operation”.The compiler does not make any checks for overlap of absolute variables with other absolute variables, so this must be considered when choosing the variable locations. There is no harm in defining more than one absolute variable to live at the same address if this is what you require. The compiler will not locate ordinary variables over the top of absolutes, so there is no overlap between these objects. When compiling for an enhanced Mid-Range PIC device, the memory allocated for some objects may be spread over multiple RAM banks. Such objects will only ever be accessed indirectly in assembly code, and will use the linear GPR memory implemented on these devices. A linear address (which can be mapped back to the ordinary banked address) will be used with these objects internally by the compiler. The address specified for absolute objects on these devices may either be the traditional banked memory address or the linear address. As the linear addresses start above the largest banked address, it is clear which address is intended. In the following example: int inputBuffer[100] @ 0x2000; it is clear that inputBuffer should placed at address 0x2000 in the linear address space, which is address 0x20 in bank 0 RAM in the traditional banked address space. See the device data sheet for exact details regarding your selected device. 3.5.4.2 ABSOLUTE OBJECTS IN PROGRAM MEMORY Non-auto objects qualified const can also be made absolute in the same way, however the address will indicate an address in program memory. For example: const int settings[] @ 0x200 = { 1, 5, 10, 50, 100 }; Both initialized and uninitialized const objects can be made absolute. That latter is useful when you only need to define a label in program memory without making a contribution to the output file. Variables can also be placed at specific positions by using the psect pragma, see Section 3.15.3.5 “The #pragma psect Directive”. The decision whether variables should be positioned this way or using absolute variables should be based on the location requirements. Using absolute variables is the easiest method, but only allows placement at an address which must be known prior to compilation. The psect pragma is more complex, but offers all the flexibility of the linker to position the new Note: Defining absolute objects can fragment memory and may make it impossible for the linker to position other objects. Avoid absolute objects if at all possible. If absolute objects must be defined, try to place them at either end of a memory bank or page so that the remaining free memory is not fragmented into smaller chunks. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 80  2010 Microchip Technology Inc. psect into memory. You can, for example, specify that variables reside at a fixed address, or that they be placed after other psects, or that the they be placed anywhere in a compiler-defined or user-defined range of address. 3.5.5 Variables in Registers Allocating variables to registers, rather than to a memory location, can make code more efficient. With HI-TECH C, there is no direct control of placement of variables in registers. The register keyword is silently ignored and has no effect on memory allocation of variables. There are very few registers available for caching of variables on PIC Baseline and Mid-Range devices, and as these registers must be frequently used by generated code for other purposes, there is little advantage in using them. The cost involved in loading variables into registers would far outweigh any advantage of accessing the register. One exception is with parameter variables. Some arguments are passed to functions in the W register rather than in a memory location; however, these values will typically be stored back to memory by code inside the function so that W can be used by code associated with that function. See Section 3.8.4 “Function Size Limits” for more information as to which parameter variables may use registers. 3.5.6 Dynamic Memory Allocation Dynamic memory allocation, (heap-based allocation using malloc etc.) is not supported with HI-TECH C. This is due to the limited amount of data memory, and the fact that this memory is banked. The wasteful nature of dynamic memory allocation does not suit itself to the 8-bit PIC device architectures. 3.5.7 Memory Models HI-TECH C does not use fixed memory models to alter allocation of variables to memory. Memory allocation is fully automatic and there are no memory model controls. 3.6 OPERATORS AND STATEMENTS The HI-TECH C compiler supports all the ANSI operators. The exact results of some of these are implementation defined. Implementation-defined behavior is fully documented in Appendix A. “Implementation-Defined Behavior”. The following sections illustrate code operations that are often misunderstood as well as additional operations that the compiler is capable of performing. 3.6.1 Integral Promotion When there is more than one operand to an operator, they typically must be of exactly the same type. The compiler will automatically convert the operands, if necessary, so they do have the same type. The conversion is to a “larger” type so there is no loss of information; however, the change in type can cause different code be ha vi our to what is sometimes expected. These form the standard type conversions. Prior to these type conversions, some operands are unconditionally converted to a larger type, even if both operands to an operator have the same type. This conversion is called integral promotion and is part of Standard C be ha vi our. The HI-TECH C compiler performs these integral promotions where required, and there are no options that can control or disable this operation. If you are not aware that the type has changed, the results of some expressions are not what would normally be expected. Integral promotion is the implicit conversion of enumerated types, signed or unsigned varieties of char, short int or bit-field types to either signed int or unsigned int. If the result of the conversion can be represented by an signed int, then that is the destination type, otherwise the conversion is to unsigned int. C Language Features  2010 Microchip Technology Inc. DS51865B-page 81 Consider the following example. unsigned char count, a=0, b=50; if(a - b < 10) count++; The unsigned char result of a - b is 206 (which is not less than 10), but both a and b are converted to signed int via integral promotion before the subtraction takes place. The result of the subtraction with these data types is -50 (which is less than 10) and hence the body of the if() statement is executed. If the result of the subtraction is to be an unsigned quantity, then apply a cast. For example: if((unsigned int)(a - b) < 10) count++; The comparison is then done using unsigned int, in this case, and the body of the if() would not be executed. Another problem that frequently occurs is with the bitwise compliment operator, ~. This operator toggles each bit within a value. Consider the following code. unsigned char count, c; c = 0x55; if( ~c == 0xAA) count++; If c contains the value 0x55, it often assumed that ~c will produce 0xAA, however the result is 0xFFAA and so the comparison in the above example would fail. The compiler may be able to issue a mismatched comparison error to this effect in some circumstances. Again, a cast could be used to change this behavior. The consequence of integral promotion as illustrated above is that operations are not performed with char -type operands, but with int -type operands. However there are circumstances when the result of an operation is identical regardless of whether the operands are of type char or int. In these cases, the HI-TECH C compiler will not perform the integral promotion so as to increase the code efficiency. Consider the following example. unsigned char a, b, c; a = b + c; Strictly speaking, this statement requires that the values of b and c should be promoted to unsigned int, the addition performed, the result of the addition cast to the type of a, and then the assignment can take place. Even if the result of the unsigned int addition of the promoted values of b and c was different to the result of the unsigned char addition of these values without promotion, after the unsigned int result was converted back to unsigned char, the final result would be the same. If an 8-bit addition is more efficient than a 16-bit addition, the compiler will encode the former. If, in the above example, the type of a was unsigned int, then integral promotion would have to be performed to comply with the ANSI C standard. 3.6.2 Rotation The C language does not specify a rotate operator; however, it does allow shifts. The compiler will detect expressions that implement rotate operations using shift and logical operators and compile them efficiently. For the following code: c = (c << 1) | (c >> 7); if c is unsigned and non-volatile, the compiler will detect that the intended operation is a rotate left of 1 bit and will encode the output using the PIC MCU rotate instructions. A rotate left of 2 bits would be implemented with code like: HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 82  2010 Microchip Technology Inc. c = (c << 2) | (c >> 6); This code optimization will also work for integral types larger than a char. If the optimization cannot be applied, or this code is ported to another compiler, the rotate will be implemented, but typically with shifts and a bitwise OR operation. 3.7 REGISTER USAGE The assembly generated from C source code by the compiler will use certain registers that are present on the PIC MCU device. Most importantly, the compiler assumes that nothing other than code it generates can alter the contents of these registers. So if the assembly loads a register with a value and no subsequent code generation requires this register, the compiler will assume that the contents of the register are still valid later in the output sequence. The registers that are special and which are used by the compiler are listed in Table 3-9 Note 1: This is a two-byte register. Both components are used by the compiler. The state of these register must never be changed directly by C code, or by any assembly code in-line with C code. The following example shows a C statement and in-line assembly that violates these rules and changes the ZERO bit in the STATUS register. #include void getInput(void) { ZERO = 0x1; // do not write using C code c = read(); #asm #include bcf ZERO_bit ; do not write using in-line assembly code #endasm process(c); } HI-TECH C is unable to interpret the meaning of in-line assembly code that is encountered in C code. Nor does it associate a variable mapped over an SFR to the actual register itself. Writing to an SFR register using either of these two methods will not flag the register as having changed and may lead to code failure. 3.8 FUNCTIONS Functions may be written in the usual way in accordance with the C language. Implementation and special features associated with functions are discussed in the following sections. 3.8.1 Function Specifiers The only specifiers that have any effect on functions are interrupt and static. TABLE 3-9: REGISTERS USED BY THE COMPILER Applicable devices Register name Baseline and all Mid-Range W Baseline and all Mid-Range STATUS All Mid-Range devices PCLATH Enhanced Mid-Range devices BSR Non-enhanced Mid-Range devices FSR Enhanced Mid-Range devices FSR0(1) Enhanced Mid-Range devices FSR1(1) C Language Features  2010 Microchip Technology Inc. DS51865B-page 83 The interrupt specifier indicates that the function is an interrupt service routine and that it is to be encoded specially to suit this task. Interrupt functions are fully described in detail in 3.9.1 “Writing an Interrupt Service Routine”. A function defined using the static specifier only affects the scope of the function, i.e. limits the places in the source code where the function may be called. Static functions may only be called from code in the file in which the function is defined. The equivalent symbol used in assembly code to represent the function may change it the function is static, see 3.13.3.1 “Equivalent Assembly Symbols”. This specifier does not change the way the function is encoded. 3.8.2 Allocation of Function Code Code associated with functions is always placed in the program memory of the target device. The program memory is paged (c.f. banking used in the data memory space). Program memory is sequential (addresses are contiguous across a page boundary), but the paging means that any call or jump from code in one page to a label in another must use a longer sequence of instructions to accomplish this. See your device data sheet for more information on the program memory and instruction set. The generated code associated with each function is initially placed in its own psect by the compiler. These psects have names such as textn, where n is a number, e.g. text98. However, psects may be merged later in the compilation process so that more than one function may contribute to a psect. Functions within the same psect can use a shorter form of call and jump to labels so it is advantageous to merge the code for as many functions into the same psect. These text psects are linked somewhere in the program memory (see 3.10 “Psects”). If the size of a psect that holds the code associated with a function exceeds the size of a page, it may be split by the assembler optimizer. A split psect will have a name of the form textn_split_s. So, for example, if the text102 psect exceeds the size of a page, it may be split into a text102_split_1 and a text102_split_2 psect. This process is fully automatic, but you should be aware that if the code associated with a function does become larger than one page in size, the efficiency of that code may drop fractionally due to any longer jump and call instruction sequences being used to transfer control to code in other pages. The basename of each psect category is tabulated below. A full list of all program-memory psects psect names are listed in Section 3.10.1.1 “Program space psects”. maintext The generated code associated with the special function, main, is placed in this psect. Some optimizations and features are not applied to this psect. textn These psects (where n is a decimal number) contain all other executable code that does not require a special link location. 3.8.3 Changing the Default Function Allocation The assembly code associated with a C function can be placed at an absolute address. This can be accomplished by using an @ address construct in a similar fashion to that used with absolute variables. Such functions are called absolute functions. The following example of an absolute function will place the function at address 400h: int mach_status(int mode) @ 0x400 { /* function body */ } If you check the assembly list file you will see the function label and the first assembly instruction associated with the function located at 0x400. You can use either the assembly list file (see 4.4 “Assembly List Files”) or map file (see 5.4 “Map Files”) to confirm that the function was moved as you expect. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 84  2010 Microchip Technology Inc. If this construct is used with interrupt functions it will only affect the position of the code associated with the interrupt function body. The interrupt context switch code that precedes the function code will not be relocated as it must be linked to the interrupt vector. See also Section2.7.22 “--CODEOFFSET: Offset Program Code to Address” for information on how to move reset and interrupt vector locations, which may be useful for designing applications such as bootloaders. Unlike absolute variables, the generated code associated with absolute functions is still placed in a psect, but the psect is dedicated to that function only. The psect name has the form below. A full list of all psect names are listed in Section 3.9 “Interrupts”. xxx_text Defines the psect for a function that has been made absolute, i.e. placed at an address. xxx will be the assembly symbol associated with the function. For example if the function rv() is made absolute, code associated with it will appear in the psect called _rv_text. Functions can also be placed at specific positions by using the psect pragma, see Section 3.15.3.5 “The #pragma psect Directive”. The decision whether functions should be positioned this way or using absolute functions should be based on the location requirements. Using absolute functions is the easiest method, but only allows placement at an address which must be known prior to compilation. The psect pragma is more complex, but offers all the flexibility of the linker to position the new psect into memory. For example, you can specify that functions reside at a fixed address, or that they be placed after other psects, or that the they be placed anywhere in a compiler-defined or user-defined range of addresses. 3.8.4 Function Size Limits For all devices, the code generated for a function may become larger than one page in size, limited only by the available program memory. However, functions that yield code larger than a page may not be as efficient due to longer call sequences to jump to and call destinations in other pages. See 3.8.2 “Allocation of Function Code” for more details. 3.8.5 Function Parameters HI-TECH C uses a fixed convention to pass arguments to a function. The method used to pass the arguments depends on the size and number of arguments involved. The compiler will either pass arguments in the W register, or in the auto-parameter block (APB) of the called function.If the first parameter is one byte in size, it is passed in the W register. All other parameters are passed in the APB. This applies to basic types and to aggregate types, like structures. The parameters are grouped along with the function’s auto variables in the APB and are placed in the compiled stack. See Section 3.5.2.2.1 “Compiled Stack Operation” for detailed information on the compiled stack. The parameter variables will be referenced as an offset from the symbol ?_function, where function is the name of the function in which the parameter is defined (i.e. the function that is to be called). Note: The names “argument” and “parameter” are often used interchangeably, but typically an argument is the actual value that is passed to the function and a parameter is the variable defined by the function to store the argu- ment. C Language Features  2010 Microchip Technology Inc. DS51865B-page 85 Unlike auto variables, parameter variables are allocated memory strictly in the order in which they appear in the function’s prototype. This means that the parameters will always be placed in the same memory bank even if the other auto variables for that function have been allocated across multiple banks. The parameters for functions that take a variable argument list (defined using an ellipsis in the prototype) are placed in the parameter memory, along with named parameters. Take, for example, the following ANSI-style function. void test(char a, int b); The function test() will receive the parameter b in its function auto-parameter block and a in the W register. A call to this function: test(xyz, 8); would generate code similar to: MOVLW 08h ; move literal 0x8 into... MOVWF ?_test ; the auto-parameter memory CLRF ?_test+1 ; locations for the 16-bit parameter MOVF _xyz,w ; move xyz into the W register CALL (_test) In this example, the parameter b is held in the memory locations ?_test (Least Significant Byte) and ?_test+1 (Most Significant Byte). The exact code used to call a function, or the code used to access a parameters from within a function, can always be examined in the assembly list file. See Section 2.7.17 “--ASMLIST: Generate Assembler List Files” for the option that generates this file. This is useful if you are writing an assembly routine that must call a function with parameters, or accept arguments when it is called. The above example does not consider data memory banking or program memory paging, which may require additional instructions. 3.8.6 Function Return Values Function return values are passed to the calling function using either the W register, or the function’s auto-parameter block. Having return values also located in the same memory as that used by the parameters can reduce the code size for functions that return a modified copy of their parameter. Eight-bit values are returned from a function in the W register. Values larger than a byte are returned in the function’s parameter memory area, with the least significant word in the lowest memory location. For example, the function: int return_16(void) { return 0x1234; } will exit with the code similar to: MOVLW 34h MOVWF (?_return_16) MOVLW 12h MOVWF (?_return_16)+1 RETURN HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 86  2010 Microchip Technology Inc. 3.8.7 Calling Functions The Baseline, Mid-Range and Enhanced Mid-Range devices all use a hardware stack for function return addresses. Although the depth of this stack is 2, 8 and 16 levels, respectively, the mechanism by which functions are called is consistent across all devices. Typically, CALL instructions are used to transfer control to a C function when it is called. Each function calls uses one level of stack. This stack level is freed after the called routine executes a RETURN instruction. The stack usage grows if a called function calls another before returning. If the hardware stack overflows, function return addresses will be destroyed and the code will eventually fail. The stackcall suboption to the --RUNTIME option controls how the compiler behaves when the compiler detects that the hardware stack is about to overflow due to too many nested calls. See Section 2.7.50 “--RUNTIME: Specify Runtime Environment” for details on this option. If this suboption is disabled (the default state), where the depth of the stack will be exceeded by a call, the compiler will issue a warning to indicate that this is the case. If the stackcall suboption is enabled, the compiler will, instead of issuing a warning, automatically swap to using a method that involves the use of a lookup table and which does not require use of the hardware stack. When the lookup method is being employed, a function is reached by a jump (not a call) directly to its address. Before this is done the address of a special "return" instruction (implemented as a jump instruction) is stored in a temporary location inside the called function. This return instruction will be able to return control back to the calling function. This means of calling functions allows functions to be nested deeply without overflowing the stack, however it does come at the expense of memory and program speed. 3.8.7.1 BANK SELECTION WITHIN FUNCTIONS A function can, and may, return with any RAM bank selected. See Section 3.5.1 “Address Spaces” for more information on RAM banks. The compiler tracks the bank selections made in the generated code associated with each function, even across function calls to other functions. If the bank that is selected when a function returns can be determined, the compiler will use this information to try to remove redundant bank selection instructions which might otherwise be inserted into the generated code. The compiler will not be able to track the bank selected by routines written in assembly, even if they are called from C code. The compiler will make no assumptions about the selected bank when such routines return. The “Tracked objects” section associated with each function and which is shown in the assembly list file relates to this bank tracking mechanism. See 4.4 “Assembly List Files” for more information of the content of these files. 3.9 INTERRUPTS The compiler incorporates features allowing interrupts to be fully handled from C code. Interrupt functions are often called Interrupt Service Routines (ISRs). Note: Baseline devices do not utilize interrupts and so the following sections are only applicable for Mid-Range and Enhanced Mid-Range devices. C Language Features  2010 Microchip Technology Inc. DS51865B-page 87 There is only one interrupt vector on Mid-Range and Enhanced Mid-Range devices. Regardless of the source of the interrupt, the device will vector to one specific location in program memory and execution continues from that address. This address is fundamental to the operation of the device and cannot be changed. Each interrupt source typically has a control bit in an SFR which can disable that interrupt source. In addition there is a global interrupt enable bit that can disable all interrupts sources and ensure that an interrupt can never occur. There is no priority of interrupt sources. Check your device data sheet for full information how your device handles interrupts. Interrupt code is the name given to any code that executes as a result of an interrupt occurring. Interrupt code completes at the point where the corresponding return from interrupt instruction is executed. This contrasts with main-line code, which, for a freestanding application, is usually the main part of the program that executes after reset. 3.9.1 Writing an Interrupt Service Routine The function qualifier interrupt may be applied to C function definitions to allow them to be called directly from the hardware interrupts. The compiler will process the interrupt function differently to any other functions, generating code to save and restore any registers used and return using a special instruction. If the PICC option --STRICT is used, the interrupt keyword becomes __interrupt. An interrupt function must be declared as type void interrupt and may not have parameters. This is the only function prototype that makes sense for an interrupt function since they are never directly called in the source code. Interrupt functions must not be called directly from C code (due to the different return instruction that is used), but they themselves may call other functions, both user-defined and library functions. Mid-Range PIC devices have many sources of interrupt, but only one interrupt vector, and hence only one interrupt function must be written. An error will result if more than one interrupt function exists in a program. An example of an interrupt function for a Mid-Range PIC MCU processor is shown here. int tick_count; void interrupt tc_int(void) { if (T0IE && T0IF) { T0IF=0; ++tick_count; return; } // process other interrupt sources here, if required } Code generated by the compiler will be placed at the interrupt vector address which will execute this function after any context switch that is required. Notice that the code in the interrupt function checks for the source of the interrupt, in this case a timer, by looking at the interrupt flag bit (T0IE) and the interrupt flag bit (T0IF). Checking the interrupt enable flag is required since interrupt flags associated with a peripheral may be asserted even if the peripheral is not configured to generate an interrupt. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 88  2010 Microchip Technology Inc. 3.9.2 Specifying the Interrupt Vector As there is only one vector location, the interrupt specifier used with a function definition is all that is required to link that function to the interrupt. Although the interrupt function can have any valid C identifier as its name, the interrupt function cannot be changed at runtime. That is, you cannot have more than one interrupt function and select which will be the active interrupt function once the program is running. 3.9.3 Context Switching 3.9.3.1 CONTEXT SAVING ON INTERRUPTS Some registers are automatically saved by the hardware when an interrupt occurs. Any registers or compiler temporary objects used by the interrupt function, other than those saved by the hardware, must be saved in software. This is the context save, or context switch code. Enhanced Mid-Range PIC devices save the W, STATUS, BSR and FSRx registers in hardware (using special shadow registers) and hence these registers do not need to be saved by software. In fact, the compiler will never have to produce code to save any other registers when compiling for an Enhanced Mid-Range as no additional registers are ever used. This makes interrupt functions on Enhanced Mid-Range PIC devices very fast and efficient. Other Mid-Range PIC processors only save the entire PC (excluding the PCLATH register) when an interrupt occurs. The the W, STATUS, FSR and PCLATH registers and the BTEMP1 pseudo register must be saved by code produced by the compiler, if required. The compiler fully determines which registers and objects are used by an interrupt function, or any of the functions that it calls (based on the call graph generated by the compiler), and saves these appropriately. Assembly code placed in-line within the interrupt function is not scanned for register usage. Thus, if you include in-line assembly code into an interrupt function, you may have to add extra assembly code to save and restore any registers or locations used. The same is true for any assembly routines called by the interrupt code. If the W register is to be saved by the compiler, it may be stored to memory reserved in the common RAM. If the processor for which the code is written does not have common memory, a byte is reserved in all RAM banks for the storage location for W register. Other registers to be saved are done so in the interrupt function’s auto area, and thus look like ordinary auto variables. 3.9.3.2 CONTEXT RESTORATION Any objects saved by software are automatically restored by software before the interrupt function returns. The order of restoration is the reverse to that used when context is saved. 3.9.4 Enabling Interrupts Two macros are available, once you have included , which control the masking of all available interrupts. These macros are ei(), which enable or unmask all interrupts, and di(), which disable or mask all interrupts. 1. The BTEMP register is a memory location allocated by the compiler, but which is treated like a register for code generation purposes. It is not used by all devices. C Language Features  2010 Microchip Technology Inc. DS51865B-page 89 On all Mid-Range PIC devices, they affect the GIE bit in the INTCON register. These macros should be used once the appropriate interrupt enable bits for the interrupts that are required in a program have been enabled. For example: ADIE = 1; // A/D interrupts will be used PEIE = 1; // all peripheral interrupts are enabled ei(); // enable all interrupts // ... di(); // disable all interrupts 3.9.5 Function Duplication It is assumed by the compiler that an interrupt may occur at any time. As all functions are not reentrant (because of the dependance on the compiled stack for local objects, see Section 3.5.2.2.1 “Compiled Stack Operation”), if a function appears to be called by an interrupt function and by main-line code this could normally lead to code failure. HI-TECH C has a feature which will duplicate the output associated with any function called from more than one call tree in the program’s call graph. There will be one call tree associated with main-line code, and one tree for the interrupt function, if defined. Main-line code will call the original function’s output, and the interrupt will call the duplicated function’s output. The duplication takes place only in the called function’s output; there is no duplication of the C source code itself. The duplicated code and data uses different symbols and are allocated different memory, so are fully independent. This is similar to the process you would need to undertake if this feature was not implemented in the compiler: the C function could be duplicated by hand, given different names and one called from main-line code; the other from the interrupt function. However, you would have to maintain both functions, and the code would need to be reverted if it was ported to a compiler which did support reentrancy. The compiler-generated duplicate will have unique identifiers for the assembly symbols used within it. The identifiers consists of the same name used in the original output prefixed with i1. The output of the function called from main-line code will not use any prefixes and the assembly names will be those normally used. To illustrate, in a program the function main calls a function called input. This function is also called by an interrupt function. Examination of the assembly list file will show assembly code for both the original and duplicate function outputs. The output corresponding to the C function input() will use the assembly label _input. The corresponding label used by the duplicate function will be i1_input. If the original function makes reference to a temporary variable, the generated output will use the symbol ??_input, compared to ??i1_input for the duplicate output. Even local labels within the function output will be duplicated in the same way. The call graph, in the assembly list file, will show the calls made to both of these functions as if they were independently written. These symbols will also be seen in the map file symbol table. Note: Never use this macro to re-enable interrupts inside the interrupt function itself. Interrupts are automatically re-enabled by hardware on execution of the RETFIE instruction. Re-enabling interrupts inside an interrupt function may result in code failure. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 90  2010 Microchip Technology Inc. This feature allows the programmer to use the same source code with compilers that use either reentrant or non-reentrant models. It does not handle cases where functions are called recursively. Code associated with library functions are duplicated in the same way. This also applies to implicitly called library routines, such as those that perform division or floating-point operations associated with C operators. 3.9.5.1 DISABLING DUPLICATION The automatic duplication of the function may be inhibited by the use of a special pragma. This should only be done if the source code guarantees that an interrupt cannot occur while the function is being called from any main-line code. Typically this would be achieved by disabling interrupts before calling the function. It is not sufficient to disable the interrupts inside the function after it has been called; if an interrupt occurs when executing the function, the code may fail. See Section 3.9.4 “Enabling Interrupts” for more information on how interrupts may be disabled. The pragma is: #pragma interrupt_level 1 The pragma should be placed before the definition of the function that is not to be duplicated. The pragma will only affect the first function whose definition follows. For example, if the function read is only ever called from main-line code when the interrupts are disabled, then duplication of the function can be prevented if it is also called from an interrupt function as follows. #pragma interrupt_level 1 int read(char device) { // ... } In main-line code, this function would typically be called as follows: di(); // turn off interrupts read(IN_CH1); ei(); // re-enable interrupts 3.10 PSECTS When the code generator outputs code and data objects, it does so into a number of standard “program sections”, referred to as psects1 . A psect is just a block of something: a block of code; a block of data etc. By having everything inside a psect, all these blocks can be easily recognized and sorted by the linker, even though they have come from different modules. One of the main jobs of the linker is to group all the psects from the entire project and place these into the available memory for the device. A psect can be created in assembly code by using the PSECT assembler directive (see Section 4.3.9.3 “PSECT”). The code generator uses this directive to direct assembly code it produces into the appropriate psect. 3.10.1 Compiler-generated Psects The code generator places code and data into psects with standard names, which are subsequent positioned by the default linker options. The linker does not treat these compiler-generated psects any differently to a psect that has been defined by yourself. 1. Some compilers use the terms section, segment, or block, but the concept is the same. C Language Features  2010 Microchip Technology Inc. DS51865B-page 91 Some psects, in particular the data memory psects, use special naming conventions. For example, take the bss psect. The name bss is historical. It holds uninitialized variables. However there may be some uninitialized variables that will need to be located in bank 0 data memory; others may need to be located in bank 1 memory. As these two groups of variables will need to be placed into different memory banks, they will need to be in separate psects so they can be independently controlled by the linker. In addition, the uninitialized variables that are bit variables need to be treated specially so they need their own psect. So there are a number of different psects that all use the same basename, but which have prefixes and suffixes to make them unique. The general form of these psect names is: [bit]psectBaseNameCLASS[div] where psectBaseName is the base name of the psect, such as bss.The CLASS is a name derived from the linker class (see Section 5.2.1 “-Aclass =low-high,...”) in which the psect will be linked, e.g. BANK0. The prefix bit is used if the psect holds bit variables. So there may be psects like: bssBANK0, bssBANK1 and bitbssBANK0 defined by the compiler to hold the uninitialized variables. If a psect has to be split into two ranges, then the letters l (elle) and h are used as div to indicate if it is the lower or higher division. A psect would be split if memory in the middle of a bank has been reserved, or is in some way not available to position objects. If an absolute variable is defined and is located anywhere inside a memory range, that range will need to be split to ensure that anything in the psects located there do not overwrite the absolute object. Thus you might see bssBANK0l and bssBANK0h psects if a split took place. The contents of these psects are described below, listed by psect base name. 3.10.1.1 PROGRAM SPACE PSECTS checksum This is a psect that is used to mark the position of a checksum that has been requested using the --CHECKSUM option, see Section 2.7.19 “--CHECKSUM: Calculate a checksum”. The checksum value is added after the linker has executed so you will not see the contents of this psect in the assembly list file, nor specific information in the map file. Linking this psect at a non-default location will have no effect on where the checksum is stored, although the map file will indicate it located at the new address. Do not change the default linker options relating to this psect. cinit Used by the C initialization runtime startup code. Code in this psect is output by the code generator along with the generated code for the C program and does not appear in the runtime startup assembly module. This psect can be linked anywhere in the program memory, provided they does not interfere with the requirements of other psects. config Used to store the configuration words. This psect must be stored in a special location in the HEX file. Do not change the default linker options relating to this psect. eeprom Used to store initial values in the EEPROM memory. Do not change the default linker options relating to this psect. idata These psects contain the ROM image of any initialized variables. These psects are copied into the data psects at startup. In this case, the class name is used to describe the class of the corresponding RAM-based data psect. These psects will be stored in program memory, not the data memory space. These psects are implicitly linked to a location that is anywhere within the CODE linker class. The linker options can be changed allowing this psect to be placed at any address in the program memory, provided it does not inter- HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 92  2010 Microchip Technology Inc. fere with the requirements of other psects. idloc Used to store the ID location words. This psect must be stored in a special location in the HEX file. Do not change the default linker options relating to this psect. init Used by assembly code in the runtime startup assembly module. The code in this and the cinit define the runtime startup code. If no interrupt code is defined code from the reset vector may “fall through” into this psect. It is recommended that the default linker options relating to this psect are not changed in case this situation is in effect. intentry Contains the entry code for the interrupt service routine which is linked to the interrupt vector. This code saves the necessary registers and jumps to the main interrupt code in the case of Mid-Range devices; for enhanced Mid-Range devices this psect will contain the interrupt function body. This psect must be linked at the interrupt vector. Do not change the default linker options relating to this psect. See the --CODEOFFSET option Section 2.7.22 “--CODEOFFSET: Offset Program Code to Address” if you want to move code when using a bootloader. jmp_tab Only used for the baseline processors, this is a psect used to store jump addresses and function return values. Do not change the default linker options relating to this psect. maintext This psect will contain the assembly code for the main() function. The code for main() is segregated as it contains the program entry point. Do not change the default linker options relating to this psect as the runtime startup code may “fall through” into this psect which requires that it be linked immediately after this code. powerup Contains executable code for a user-supplied power-up routine. Do not change the default linker options relating to this psect. reset_vec This psect contains code associated with the reset vector. Do not change the default linker options relating to this psect as it must be linked to the reset vector location of the target device. See the --CODEOFFSET option Section 2.7.22 “--CODEOFFSET: Offset Program Code to Address” if you want to move code when using a bootloader. reset_wrap For baseline PIC devices, this psect contains code which is executed after the device PC has wrapped around to address 0x0 from the oscillator calibration location at the top of program memory. Do not change the default linker options relating to this psect as it must be linked to the reset vector location of the target device. strings The strings psect is used for const objects. It also includes all unnamed string literals. This psect is linked into ROM, since the contents do not need to be modified. This psect can be linked anywhere in the program memory, provided it does not cross a 100h boundary or interfere with the requirements of other psects. stringtext The stringtext psect is used for const objects when compiling for Baseline devices. This psect is linked into ROM, since the contents do not need to be modified. This psect must be linked within the first half of each program memory page. textn These psects (where n is a decimal number) contain all other executable code that does not require a special link location. These psects can be linked anywhere in the program memory, provided they does not interfere with the requirements of other psects. C Language Features  2010 Microchip Technology Inc. DS51865B-page 93 xxx_text Defines the psect for a function that has been made absolute, i.e. placed at an address. xxx will be the assembly symbol associated with the function. For example if the function rv() is made absolute, code associated with it will appear in the psect called _rv_text. As these psects are already placed at the address indicated in the C source code, the linker options that position them should not be changed. 3.10.1.2 DATA SPACE PSECTS nv These psects are used to store variables qualified persistent. They are not cleared or otherwise modified at startup. These psects may be linked anywhere in their targeted memory bank and should not overlap any common (unbanked memory) that the device supports if it is a banked psect. bss These psects contain any uninitialized variables. These psects may be linked anywhere in their targeted memory bank and should not overlap any common (unbanked memory) that the device supports if it is a banked psect. data These psects contain the RAM image of any initialized variables. These psects may be linked anywhere in their targeted memory bank and should not overlap any common (unbanked memory) that the device supports if it is a banked psect. cstack These psects contain the compiled stack. On the stack are auto and parameter variables for the entire program. See 3.5.4 “Absolute Variables” for information on the compiled stack. These psects may be linked anywhere in their targeted memory bank and should not overlap any common (unbanked memory) that the device supports if it is a banked psect. 3.11 MAIN, RUNTIME STARTUP AND RESET The identifier main is special. It is must be used as the name of a function that will be the first function to execute in a program. You must always have one and only one function called main() in your programs. Code associated with main(), however, is not the first code to execute after reset. Additional code provided by the compiler and known as the runtime startup code is executed first and is responsible for transferring control to the main() function. 3.11.1 Runtime Startup Code A C program requires certain objects to be initialized and the processor to be in a particular state before it can begin execution of its function main(). It is the job of the runtime startup code to perform these tasks, specifically (and in no particular order): • Initialization of global variables assigned a value when defined • Clearing of non-initialized global variables • General setup of registers or processor state Rather than the traditional method of linking in a generic, precompiled routine, HI-TECH C Compiler for PIC10/12/16 MCUs uses a more efficient method which actually determines what runtime startup code is required from the user’s program. Details of the files used and how the process can be controlled are described in Section 2.4.2 “Runtime Startup Code”. The follow sections detail exactly what the runtime startup code actually does. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 94  2010 Microchip Technology Inc. PICCThe runtime startup code is executed before main(), but If you require any special initialization to be performed immediately after reset, you should use power-up feature described later in Section 3.11.2 “The Powerup Routine”. 3.11.1.1 INITIALIZATION OF OBJECTS One task of the runtime startup code is to ensure that any initialized variables contain their initial value before the program begins execution. Initialized variables are those which are not auto objects and which are assigned an initial value in their definition, for example input in the following example. int input = 88; void main(void) { ... Such initialized objects have two components: their initial value (0x0088 in the above example) stored in program memory (i.e. placed in the HEX file), and space for the variable reserved in RAM it will reside and be accessed during program execution (runtime). The psects used for storing these components are described in Section 3.10.1 “Compiler-generated Psects”. The runtime startup code will copy all the blocks of initial values from program memory to RAM so the variables will contain the correct values before main() is executed. Since auto objects are dynamically created, they require code to be positioned in the function in which they are defined to perform their initialization. It is possible that the initial value of an auto object may change on each instance of the function and so the initial values cannot be stored in program memory and copied. As a result, initialized auto objects are not considered by the runtime startup code but are instead initialized by assembly code in each function output. Variables whose contents should be preserved over a reset, or even power off, should be qualified with the persistent qualifier, see Section 3.4.7.1 “Persistent Type Qualifier”. Such variables are linked at a different area of memory and are not altered by the runtime startup code in any way. If this action is required, the code executed will destroy the contents of the STATUS register. If the contents of this register, particularly the TO and PD bits are required to determine the cause of reset, you can choose to have a copy of this register taken so that it can later be examined. See Section 3.11.1.3 “STATUS Register Preservation” for more information. 3.11.1.2 CLEARING OBJECTS Those non-auto objects which are not initialized must be cleared before execution of the program begins. This task is also performed by the runtime startup code. Uninitialized variables are those which are not auto objects and which are not assigned a value in their definition, for example output in the following example. int output; void main(void) { ... Such uninitialized objects will only require space to be reserved in RAM where they will reside and be accessed during program execution (runtime). The psects used for storing these components are described in Section 3.10.1 “Compiler-generated Psects” and typically have a name based on the initialism “bss” (Block Started by Symbol). Note: Initialized auto variables can impact on code performance, particularly if the objects are large in size. Consider using global or static objects instead. C Language Features  2010 Microchip Technology Inc. DS51865B-page 95 The runtime startup code will clear all the memory location occupied by uninitialized variables so they will contain zero before main() is executed. Variables whose contents should be preserved over a reset should be qualified with persistent. See Section 3.4.7.1 “Persistent Type Qualifier” for more information. Such variables are linked at a different area of memory and are not altered by the runtime startup code in any way. If this action is required, the code executed will destroy the contents of the STATUS register. If the contents of this register, particularly the TO and PD bits are required to determine the cause of reset, you can choose to have a copy of this register taken so that it can later be examined. See Section 3.11.1.3 “STATUS Register Preservation” for more information. 3.11.1.3 STATUS REGISTER PRESERVATION The resetbits suboption of the --RUNTIME option (see 2.7.50 “--RUNTIME: Specify Runtime Environment”) preserves some of the bits in the STATUS register before being clobbered by the remainder of the runtime startup code. The state of these bits can be examined after recovering from a reset condition to determine the cause of the reset. The entire STATUS register is saved to an assembly variable ___resetbits. This variable can be accessed from C code using the declaration: extern unsigned char __resetbits; The assembly equates ___powerdown and ___timeout represent the bit address of the powerdown and timeout bits within the STATUS register and can be used if required. These can be accessed from C code using the declarations: extern bit __powerdown; extern bit __timeout; See Section 2.8 “MPLAB IDE Universal Toolsuite Equivalents” for use of this option in MPLAB IDE. 3.11.2 The Powerup Routine Some hardware configurations require special initialization, often within the first few instruction cycles after reset. To achieve this there is a hook to the reset vector provided via the powerup routine. This routine can be supplied in a user-defined assembler module that will be executed immediately after reset. A template powerup routine is provided in the file powerup.as which is located in the sources directory of your compiler distribution. Refer to comments in this file for more details. The file should be copied to your working directory, modified and included into your project as a source file. No special linker options or other code is required. The compiler will detect if you have defined a powerup routine and will automatically use it, provided the code in this routine is contained in a psect called powerup. For correct operation (when using the default compiler-generated runtime startup code), the code must end with a GOTO instruction to the label called start. As with all user-defined assembly code, it must take into consideration program memory paging and/or data memory banking, as well as any applicable errata issues for the device you are using. The program’s entry point is already defined by the runtime startup code, so this should not be specified in the power-up routine with the END directive (if used). See Section 4.3.9.2 “END” for more information on this assembler directive. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 96  2010 Microchip Technology Inc. 3.12 LIBRARY ROUTINES 3.12.0.1 USING LIBRARY ROUTINES Library functions or routines (and any associated variables) will be automatically linked into a program once they have been referenced in your source code. The use of a function from one library file will not include any other functions from that library. Only used library functions will be linked into the program output and consume memory. Your program will require declarations for any functions or symbols used from libraries. These are contained in the standard C header (.h) files. Header files are not library files and the two files types should not be confused. Library files contain precompiled code, typically functions and variable definitions; the header files provide declarations (as opposed to definitions) for functions, variables and types in the library files, as well as other preprocessor macros. #include // declare function prototype for sqrt void main(void) { double i; // sqrt referenced; sqrt will be linked in from library file i = sqrt(23.5); } 3.12.1 The printf Routine The code associated with the printf function is not found in the library files. The printf() function is generated from a special C template file that is customized after analysis of the user’s C code. See Section “PRINTF, VPRINTF” for more information on the printf library function. The template file is found in the lib directory of the compiler distribution and is called doprnt.c. It contains a minimal implementation of the printf() function, but with the more advanced features included as conditional code which can be utilized via preprocessor macros that are defined when it is compiled. The parser and code generator analyze the C source code, searching for calls to the printf function. For all calls, the placeholders that were specified in the printf() format strings are collated to produce a list of the desired functionality of the final function. The doprnt.c file is then preprocessed with the those macros specified by the preliminary analysis, thus creating a custom printf() function for the project being compiled. After parsing, the p-code output derived from doprnt.c is then combined with the remainder of the C program in the final code generation step. For example, if a program contains one call to printf(), which looks like: printf(”input is: %d”); The compiler will note that only the %d placeholder is used and the doprnt.c module that is linked into the program will only contain code that handles printing of decimal integers. Consider now that the code is changed and another call to printf() is added. The new call looks like: printf(”output is %6d”); Now the compiler will detect that additional code to handle printing decimal integers to a specific width must be enabled as well. As more features of printf() are detected, the size of the code generated for the printf() function will increase. C Language Features  2010 Microchip Technology Inc. DS51865B-page 97 If the format string in a call to printf() is not a string literal as above, but is rather a pointer to a string, then the compiler will not be able to reliably predict the printf() usage, and so it forces a more complete version of printf() to be generated. However, even without being able to scan printf() placeholders, the compiler can still make certain assumptions regarding the usage of the function. In particular, the compiler can look at the number and type of the additional arguments to printf() (those following the format string expression) to determine which placeholders could be valid. This enables the size and complexity of the generated printf() routine to be kept to a minimum even in this case. For example, if printf() was called as follows: printf(myFormatString, 4, 6); the compiler could determine that, for example, no floating-point placeholders are required and omit these from being included in the printf() function output. As the arguments after the format string are non-prototyped parameters, their type must match that of the placeholders. No aspect of this operation is user-controllable (other than by adjusting the calls to printf() ), however the actual printf() code used by a program can be observed. If compiling a program using printf(), the driver will leave behind the pre-processed version of doprnt.c. This module, called doprnt.pre in your working directory, will show the C code that will actually be contained in the printf routine. As this code has been pre-processed, indentation and comments will have been stripped out as part of the normal actions taken by the C pre-processor. 3.13 MIXING C AND ASSEMBLY CODE Assembly language code can be mixed with C code using two different techniques: writing assembly code and placing it into a separate assembler module, or including it as in-line assembly in a C module. For the latter, there are two formats in which this can be done, described below. 3.13.1 Integrating Assembly Language Modules Entire functions may be coded in assembly language as separate .as or .asm source files included into your project. They will be assembled and combined into the output image using the linker. The following are guidelines that must be adhered to when writing a routine in a C-callable assembly routine. • Select, or define, a suitable psect for the executable assembly code • Select a name (label) for the routine using a leading underscore character • Ensure that the routine’s label is globally accessible from other modules • Select an appropriate equivalent C prototype for the routine on which argument passing can be modelled • Limit arguments and return values to single byte-sized objects (Assembly routines may not define variables that reside in the compiled stack. Use global variables Note: The more assembly code a project contains, the more difficult and time consuming will be its maintenance. As the project is developed, the compiler may work in different ways as some optimizations look at the entire program. The assembly code is more likely to fail if the compiler is updated due to differences in the way the updated compiler may work. These factors do not affect code written in C. If assembly must be added, it is preferable to write this as self-contained routine in a separate assembly module rather than in-lining it in C code. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 98  2010 Microchip Technology Inc. for additional arguments.) • Optionally, use a signature value to enable type checking when the function is called • Use bank selection instructions and mask addresses of symbols • The following example goes through these steps. A mapping is performed on the names of all C functions and non-static global variables. See Section 3.13.3.1 “Equivalent Assembly Symbols” for a complete description of mappings between C and assembly identifiers. An assembly routine is required which can add an 8-bit quantity passed to the routine with the contents of PORTB and return this as an 8-bit quantity. Most compiler-generated executable code is placed in psects called textn, where n is a number. (see Section 3.10.1 “Compiler-generated Psects”). We will create our own text psect based on the psect the compiler uses. Check the assembly list file to see how the text psects normally appear. You may see a psect such as the following generated by the code generator. PSECT text0,local,class=CODE,delta=2 See Section 4.3.9.3 “PSECT” for detailed information on the flags used with the PSECT assembler directive. This psect is called text0. It is flagged local, which means that it is distinct from other psects with the same name. It lives in the CODE class. This flag is important as it means it will be automatically placed in the area of memory set aside for code. With this flag in place, you do not need to adjust the default linker options to have the psect correctly placed in memory. The last option, the delta value, is also very important. This indicates that the memory space in which the psect will be placed is word addressable (value of 2). The PIC10/12/16 program memory space is word addressable; the data space is byte addressable. We simply need to choose a different name, so we might choose the name mytext, as the psect name in which we will place out routine, so we have: PSECT mytext,local,class=CODE,delta=2 Let’s assume we would like to call this routine add in the C domain. In assembly domain we must choose the name _add as this then maps to the C identifier add. If we had chosen add as the assembly routine, then it could never be called from C code. The name of the assembly routine is the label that we will place at the beginning of the assembly code. The label we would use would look like this. _add: We need to be able to call this from other modules, some make this label globally accessible, by using the GLOBAL assembler directive (Section 4.3.9.1 “GLOBAL”). GLOBAL _add By compiling a dummy C function with a similar prototype to this assembly routine, we can determine the signature value. The C-equivalent prototype to this routine would look like: int add(int, int); Check the assembly list file for the signature value of such a function. Signature values are not mandatory, but allow for additional type checking to be made by the linker. We determine that the following SIGNAT directive (Section 4.3.9.20 “SIGNAT”) can be used. SIGNAT _add,4217 The W register will be used for passing in the argument. C Language Features  2010 Microchip Technology Inc. DS51865B-page 99 Here is an example of the complete routine for a Mid-Range device which could be placed into an assembly file and added to your project. The GLOBAL and SIGNAT directives do not generator code, and hence do not need to be inside the mytext psect, although you can place them there if you prefer. The BANKSEL directive and BANKMASK macro have been used to ensure that the correct bank was selected and that all addresses are masked to the appropriate size. #include GLOBAL _add ; make _add globally accessible SIGNAT _add,4217 ; tell the linker how it should be called ; everything following will be placed into the mytext psect psect mytext,local,class=CODE,delta=2 ; our routine to add to ints and return the result _add: ; W is loaded by the calling function; BANKSEL (PORTB) ; select the bank of this object ADDWF BANKMASK(PORTB),w ; add parameter to port ; the result is already in the required location (W)so we can ; just return immediately RETURN To compile this, the assembly file must be preprocessed as we have used the C preprocessor #include directive. See Section 2.7.11 “-P: Preprocess Assembly Files”. To call an assembly routine from C code, a declaration for the routine must be provided. This ensures that the compiler knows how to encode the function call in terms of parameters and return values. Here is a C code snippet that declares the operation of the assembler routine, then calls the routine. // declare the assembly routine so it can be correctly called extern unsigned char add(unsigned char a); void main(void) { volatile unsigned char result; a = read_port(); result = add(5); // call the assembly routine } 3.13.2 #asm, #endasm and asm() PIC MCU instructions may also be directly embedded “in-line” into C code using the directives #asm, #endasm or the statement asm();. The #asm and #endasm directives are used to start and end a block of assembly instructions which are to be embedded into the assembly output of the code generator. The #asm block is not syntactically part of the C program, and thus it does not obey normal C flow-of-control rules. This means that you should not use this form of in-line assembly inside C constructs like if(), while() and for() statements. However this is the easiest means of adding multiple assembly instructions. The asm() statement is used to, typically, embed a single assembler instruction. This form looks and behaves like a C statement. Only one assembly instruction may be encapsulated within each asm() statement. You can specify more than one assembly instruction inside one asm() statement by separating the instructions with a \n character, (e.g. asm("movlw 55\nmovwf _x");) although code will be more readable if you one place one instruction in each statement and use multiple statements. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 100  2010 Microchip Technology Inc. You may use the asm(" ") form of in-line assembly at any point in the C source code as it will correctly interact with all C flow-of-control structures. The following example shows both methods used: unsigned int var; void main(void) { var = 1; #asm // like this... BCF 0,3 BANKSEL(_var) RLF (_var)&07fh RLF (_var+1)&07fh #endasm // do it again the other way... asm("BCF 0,3" ); asm("BANKSEL _fvar"); asm("RLF (_var)&07fh" ); asm("RLF (_var+1)&07fh" ); } When using in-line assembler code, great care must be taken to avoid interacting with compiler-generated code. The code generator cannot scan the assembler code for register usage and so will remain unaware if registers are clobbered or used by the assembly code. If you are in doubt as to which registers are being used in surrounding code, compile your program with the --ASMLIST option (see Section 2.7.17 “--ASMLIST: Generate Assembler List Files”) and examine the assembler code generated by the compiler. Remember that as the rest of the program changes, the registers and code strategy used by the compiler will change as well. 3.13.3 Accessing C objects from within Assembly Code The following sections apply to both separate assembly modules, and assembly in-line with C code. 3.13.3.1 EQUIVALENT ASSEMBLY SYMBOLS Most C symbols map to an corresponding assembly equivalent. The name of a C function maps to an assembler label that will have the same name, but with an underscore prepended. So the function main() will define an assembly label _main. This mapping is such that an ordinary symbol defined in the assembly domain cannot interfere with an ordinary symbol in the C domain. So for example, if the symbol main is defined in the assembly domain, it is quite distinct to the main symbol used in C code and they refer to different locations. If the C function is qualified static, and there is more than one function in the program with exactly the same name, the name of the first function will map to the usual assembly symbol and the subsequent functions will map to a special symbol of the form: fileName@functionName, where fileName is the name of the file that contains the function, and functionName is the name of the function. For example a program contains the definition for two static functions, both called add. One lives in the file main.c and the other in lcd.c. The first function will generate an assembly label _add. The second will generate the label lcd@add. C Language Features  2010 Microchip Technology Inc. DS51865B-page 101 The name of a non-auto C variable also maps to an assembler label that will have the same name, but with an underscore prepended. So the variable result will define an assembly label: _result. If the C variable is qualified static, there, again, is a chance that there could be more than one variable in the program with exactly the same C name. The same rules apply to variables as to functions. The name of the first variable will map to a special symbol prepended with an underscore; the subsequent symbols will have the form: fileName@variableName, where fileName is the name of the file that contains the variable, and variableName is the name of the variable. For example a program contains the definition for two static variables, both called result. One lives in the file main.c and the other in lcd.c. The first function will generate an assembly label _result. The second will generate the label lcd@result. If there is more than one static function with the same name, and they contain definitions for static variables of the same name, then the assembly symbol used for these variables will be of the form: fileName@functionName@variableName. To make accessing of parameter and auto variables easier, special equates are defined which map a unique symbol to each variable. The symbol has the form: functionName@variableName. Thus, if the function main defines an auto variable called foobar, the symbol main@foobar can be used in assembly code to access this C variable. 3.13.3.2 ACCESSING REGISTERS FROM ASSEMBLY CODE If writing separate assembly modules, SFR definitions will not automatically be accessible. The assembly header file can be used to gain access to these register definitions. Do not use this file for assembly in-line with C code as it will clash with definitions in . Include the file using the assembler’s INCLUDE directive, (see Section 4.3.10.3 “INCLUDE”) or use the C preprocessor’s #include directive. If you are using the latter method, make sure you compile with the -P driver option to preprocess assembly files, see Section 2.7.11 “-P: Preprocess Assembly Files”. The symbols in this header file look similar to the identifiers used in the C domain when including , e.g. PORTA, EECON1 etc. They are different symbols in different domains, but will map to the same memory location. Bits within registers are defined as the registerName,bitNumber. So for example, RA0 is defined as PORTA,0. Here is an example of an assembly module that uses SFRs. #include GLOBAL _setports PSECT text,class=CODE,local,delta=2 _setports: MOVLW 0xAA BANKSEL (PORTA) MOVWF BANKMASK(PORTA) BANKSEL (PORTB) BSF RB1 If you wish to access register definitions from assembly that is in-line with C code, a different header file is available for this purpose. Include the header file into the assembly code. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 102  2010 Microchip Technology Inc. The symbols used for register names will be the same as those defined by ; however, the names assigned to bit variables within the registers will include the suffix _bit. So for example, the example given previously could be rewritten as in-line assembly as follows. #asm MOVLW 0xAA BANKSEL (PORTA) MOVWF BANKMASK(PORTA) BANKSEL (PORTB) BSF RB1_bit #endasm 3.13.4 Interaction between Assembly and C Code HI-TECH C Compiler for PIC10/12/16 MCUs incorporates several features designed to allow C code to obey requirements of user-defined assembly code. The command-line driver ensures that all user-defined assembly files have been processed first, before compilation of C source files begin. The driver is able to read and analyze certain information in the relocatable object files and pass this information to the code generator. This information is used to ensure the code generator takes into account requirement of the assembly code. See Section 2.3.4 “Compilation of Assembly Source” for further information on the compile sequence. 3.13.4.1 ABSOLUTE PSECTS Some of the information that is extracted from the relocatable objects relates to absolute psects, specifically psects defined using the abs and ovrld, PSECT flags, see Section 4.3.9.3 “PSECT” for information on this directive. HI-TECH C is able to determine the address bounds of absolute psects and uses this information to ensure that the code produced by the code generator does not use memory required by the assembly code. The code generator will reserve any memory used by the assembly code. Here is an example of how this works. An assembly code files defines a table that must be located at address 0x110 in the data space. The assembly file contains: PSECT lkuptbl,class=RAM,space=1,abs,ovlrd ORG 110h lookup: DS 20h An absolute psect always starts at address 0. For such psects, you can specify a non-zero starting address by using the ORG directive. See Section 4.3.9.4 “org” for important information on this directive. When the project is compiled, this file is assembled and the resulting relocatable object file scanned for absolute psects. As this psect is flagged as being abs and ovlrd, the bounds and space of the psect will be noted — in this case a memory range from address 0x110 to 0x12F in memory space 1 is being used. This information is passed to the code generator to ensure that this address range are not used by the C code. The linker handles all of the allocation into program memory, and so only the psects located in data memory need be defined in this way. 3.13.4.2 UNDEFINED SYMBOLS If a variable needs to be accessible from both assembly and C source code, it can be defined in assembly code, if required, but it is easier to do so in C source code. C Language Features  2010 Microchip Technology Inc. DS51865B-page 103 A problem could occur if there is a variable defined in C source, but is only ever referenced in the assembly code. In this case, the code generator would remove the variable believing it is unused. The linker would be unable to resolve the symbol referenced by the assembly code and an error will result. To work around this issue, HI-TECH C also searches assembly-derived object files for symbols which are undefined. These will be symbols that are used, but not defined, in assembly code. The code generator is informed of these symbols, and if they are encountered in the C code, the variable is automatically marked as being volatile. This action has the same effect as qualifying the variable volatile in the source code, see Section 3.4.6.2 “Volatile Type Qualifier”. Variables qualified as volatile will never be removed by the code generator, even if they appear to be unused throughout the program. For example, if a C program defines a global variable as follows: int input; but this variable is only ever used in assembly code. The assembly module(s) can simply declare this symbol using the GLOBAL assembler directive, and then use it. GLOBAL _input, _raster PSECT text,local,class=CODE,delta=2 _raster: MOVF _input,w The compiler knows of the mapping between the C symbol input, and the corresponding assembly symbol _input (see Section 3.13.3.1 “Equivalent Assembly Symbols”). In this instance the C variable input will not be removed and be treated as if it was qualified volatile. 3.14 OPTIMIZATIONS The optimizations in HI-TECH C compiler can broadly be broadly grouped into: C-level optimizations performed on the source code before conversion into assembly; and Assembly-level optimizations performed on the assembly code generated by the compiler Of the C-level optimizations, these can be considered as those that: • Simplify or change the C expressions; and • Allocate variables to registers An example of where the code expression may be simplified is this: Consider if the original C code read: a = b + c; but the compiler is able to determine that the variable c at this point will always hold the value 5. The code expression is essentially changed so that it reads: a = b + 5; This may result in more efficient code after it is built by the compiler. These sorts of optimizations are inherent in the compilation process and cannot be disabled. They may reduce both code and data size. Allocation of variables to registers is performed after analyzing the assembly code that is initially generated from the C code. Registers can typically be accessed with less code compared to reading from memory. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 104  2010 Microchip Technology Inc. Those registers which are unused for each C statement are noted. Variables are allocated an available register while it is unused. The cost associated with moving the variable from memory to a register is considered before the move takes place. The code is then recompiled, but this time with the variables residing in their allocated registers. The process repeats until no more registers are available. A variable may move from one register to another within a function; it may spend some of its duration in a register and some in its allocated memory location, or its entire duration in a register. The global optimization level may have some impact on the register allocation. The level of this optimizer (1-9) affects how hard the compiler tries to force variables into registers. Note that even if the global optimizer is disabled, there may still be use of registers for variables in a program. For 8-bit PIC devices the global optimizer has a very limited effect and often it makes little difference to code or data size. As C-level optimizations are performed before debug information is produced, they tend to have less impact on debugging information. Note, however, if a variable is located in a register IDEs, such as MPLAB IDE, may indicate incorrect values in their Watch view. This is due to a limitation in the file format used to pass debug information to the IDE (which is currently COFF). Check the assembly list file to see if registers are using in the routine being debugged. Of the assembler optimizations, the actions performed include: • In-lining of small routines • Procedural abstraction • Jump-to-jump type optimizations • Peephole optimizations These optimizations can often interfere with debugging in tools such as MPLAB IDE and it may be necessary to disable them, if possible. The assembler optimizations can drastically reduce code size, although typically have little effect on RAM usage. 3.15 PREPROCESSING All C source files are preprocessed before compilation. The preprocessed file is always left behind and will have a .pre extension and the same base name as the source file from which it is derived. The --PRE option can be used to preprocess and then stop the compilation. See Section 2.7.46 “--PRE: Produce Preprocessed Source Code”. Assembler files can also be preprocessed if the -P driver option is issued. See Section 2.7.11 “-P: Preprocess Assembly Files”. 3.15.1 Preprocessor Directives HI-TECH C accepts several specialized preprocessor directives in addition to the standard directives. All of these are listed in Table 3-10. Macro expansion using arguments can use the # character to convert an argument to a string, and the ## sequence to concatenate arguments. TABLE 3-10: PREPROCESSOR DIRECTIVES Directive Meaning Example # Preprocessor null directive, do nothing # #assert Generate error if condition false #assert SIZE > 10 #asm Signifies the beginning of in-line assembly #asm MOVLW FFh #endasm C Language Features  2010 Microchip Technology Inc. DS51865B-page 105 The type and conversion of numeric values in the preprocessor domain is the same as in the C domain. Preprocessor values do not have a type, but acquire one as soon as they are converted by the preprocessor. Expressions may overflow their allocated type in the same way that C expressions may overflow. Overflow may be avoided by using a constant suffix. For example, an L after the number indicates it should be interpreted as a long once converted. So for example #define MAX 1000*1000 and #define MAX 1000*1000L will define the values 0x4240 and 0xF4240, respectively. #define Define preprocessor macro #define SIZE 5 #define FLAG #define add(a,b) ((a)+(b)) #elif Short for #else #if see #ifdef #else Conditionally include source lines see #if #endasm Terminate in-line assembly see #asm #endif Terminate conditional source inclusion see #if #error Generate an error message #error Size too big #if Include source lines if constant expression true #if SIZE < 10 c = process(10) #else skip(); #endif #ifdef Include source lines if preprocessor symbol defined #ifdef FLAG do_loop(); #elif SIZE == 5 skip_loop(); #endif #ifndef Include source lines if preprocessor symbol not defined #ifndef FLAG jump(); #endif #include Include text file into source #include #include "project.h" #line Specify line number and filename for listing #line 3 final #nn (Where nn is a number) short for #line nn #20 #pragma Compiler specific options Refer to Section 3.15.3 “Pragma Directives” #undef Undefines preprocessor symbol #undef FLAG #warning Generate a warning message #warning Length not set TABLE 3-10: PREPROCESSOR DIRECTIVES (CONTINUED) Directive Meaning Example HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 106  2010 Microchip Technology Inc. 3.15.2 Predefined Macros The compiler drivers define certain symbols to the preprocessor, allowing conditional compilation based on chip type etc. The symbols listed in Table 3-11 show the more common symbols defined by the drivers. TABLE 3-11: PREDEFINED MACROS Symbol When set Usage HI_TECH_C Always To indicate that the compiler in use is HI-TECH C® compiler. _HTC_VER_MAJOR_ Always To indicate the integer component of the compiler’s version number. _HTC_VER_MINOR_ Always To indicate the decimal component of the compiler’s version number. _HTC_VER_PATCH_ Always To indicate the patch level of the compiler’s version number. _HTC_EDITION_ Always Indicates which of PRO, Standard or Lite compiler is in use. Values of 2, 1 or 0 are assigned respectively. __PICC__ Always Indicates HI-TECH compiler for Microchip PIC10/12/16 in use. _MPC_ Always Indicates compiling for Microchip PIC® MCU family. _PIC12 If Baseline (12-bit) device To indicate selected device is a baseline PIC devices. _PIC14 If Mid-Range (14-bit) device To indicate selected device is a Mid-Range PIC devices. _PIC14E If Enhanced Mid-Range (14 bit) device To indicate selected device is an Enhanced Mid-Range PIC devices. _COMMON_ If common RAM present To indicate whether device has common RAM area. _BANKBITS_ Always Assigned 0, 1 or 2 to indicate 1, 2 or 4 available banks or RAM. _GPRBITS_ Always Assigned 0, 1 or 2 to indicate 1, 2 or 4 available banks or general purpose RAM. __MPLAB_ICDX__ If compiling for MPLAB® ICD or MPLAB ICD 2/3 debugger (where X is empty, 2 or 3. Assigned 1 to indicate that the code is generated for use with the Microchip MPLAB ICD,ICD 2 or ICD 3. MPLAB_ICD If compiling for MPLAB® ICD or MPLAB ICD 2/3 debugger Assigned 1 to indicate that the code is generated for use with the Microchip MPLAB ICD 1. Assigned 2 for MPLAB ICD 2; 3 for MPLAB ICD 3. __MPLAB_PICKITX__ If compiling for MPLAB® PICKIT 2/3 Assigned 1 to indicate that the code is generated for use with the Microchip MPLAB PICKIT 2 or PICKIT 3 C Language Features  2010 Microchip Technology Inc. DS51865B-page 107 Each symbol, if defined, is equated to 1 unless otherwise stated. 3.15.3 Pragma Directives There are certain compile-time directives that can be used to modify the behavior of the compiler. These are implemented through the use of the ANSI standard #pragma facility. The format of a pragma is: #pragma keyword options where keyword is one of a set of keywords, some of which are followed by certain options. A list of the keywords is given in Table 3-12. Those keywords not discussed elsewhere are detailed below. __MPLAB_REALICE__ If compiling for MPLAB® REALICE Assigned 1 to indicate that the code is generated for use with the Microchip MPLAB REALICE. _ROMSIZE Always To indicate how many words of program memory are available. _EEPROMSIZE Always To indicate how many bytes of EEPROM are available. _CHIPNAME When chip selected To indicate the specific chip type selected, e.f. _16F877 __FILE__ Always To indicate this source file being preprocessed. __LINE__ Always To indicate this source line number. __DATE__ Always To indicate the current date, e.g. May 21 2004 __TIME__ Always To indicate the current time, e.g. 08:06:31. TABLE 3-12: PRAGMA DIRECTIVES Directive Meaning Example inline Specify function is inline #pragma inline(fabs) interrupt_level Allow call from interrupt and main-line code #pragma interrupt_level 1 pack Specify structure packing #pragma pack 1 printf_check Enable printf-style format string checking #pragma printf_check(printf) const psect Rename compiler-generated psect #pragma psect nvBANK0=my_nvram regsused Specify registers used by function #pragma regsused wreg,fsr switch Specify code generation for switch statements #pragma switch direct warning Control messaging parameters #pragma warning disable 299,407 TABLE 3-11: PREDEFINED MACROS (CONTINUED) Symbol When set Usage HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 108  2010 Microchip Technology Inc. 3.15.3.1 THE #PRAGMA INLINE DIRECTIVE The #pragma inline directive is used to indicate to the compiler that a function will be inlined. The directive is only usable with special functions that the code generator will handle specially, e.g the _delay function. 3.15.3.2 THE #PRAGMA INTERRUPT_LEVEL DIRECTIVE The #pragma interrupt_level directive can be used to prevent function duplication of functions called from main-line and interrupt code. See Section 3.9.5.1 “Disabling Duplication” for more information. 3.15.3.3 THE #PRAGMA PACK DIRECTIVE Some MCUs requires word accesses to be aligned on word boundaries. Consequently the compiler will align all word or larger quantities onto a word boundary, including structure members. This can lead to “holes” in structures, where a member has been aligned onto the next word boundary. This behavior can be altered with this directive. Use of the directive #pragma pack 1 will prevent any padding or alignment within structures. Use this directive with caution - in general if you must access data that is not aligned on a word boundary you should do so by extracting individual bytes and re-assembling the data. This will result in portable code. Note that this directive must not appear before any system header file, as these must be consistent with the libraries supplied. PIC10/12/16 devices can only perform byte accesses to memory and so do not require any alignment of memory objects. This pragma will have no effect when used. 3.15.3.4 THE #PRAGMA PRINTF_CHECK DIRECTIVE Certain library functions accept a format string followed by a variable number of arguments in the manner of printf(). Although the format string is interpreted at runtime, it can be compile-time checked for consistency with the remaining arguments. This directive enables this checking for the named function, for example the system header file includes the directive: #pragma printf_check(printf) const to enable this checking for printf(). You may also use this for any user-defined function that accepts printf -style format strings. The qualifier following the function name is to allow automatic conversion of pointers in variable argument lists. The above example would cast any pointers to strings in RAM to be pointers of the type (const char *) Note that the warning level must be set to -1 or below for this option to have any visible effect. See Section 2.7.59 “--WARN: Set Warning Level”. 3.15.3.5 THE #PRAGMA PSECT DIRECTIVE Normally the object code generated by the compiler is broken into the standard psects as described in 3.10.1 “Compiler-generated Psects”. This is fine for most applications, but sometimes it is necessary to redirect variables or code into different psects when a special memory configuration is desired. Some code and data compiler-generated psects may be redirected using a #pragma psect directive. The general form of this pragma looks like: #pragma psect standardPsect=newPsect Note: Use of this pragma with a user-defined function does not mean that function will be in-lined. C Language Features  2010 Microchip Technology Inc. DS51865B-page 109 and instructs the code generator that anything that would normally appear in the standard psect standardPsect, will now appear in a new psect called newPsect. This psect will be identical to standardPsect in terms of its flags and attributes, however will have a unique name. Thus, you can explicitly position this new psect without affecting the placement of anything in the original psect. If the name of the standard psect that is being redirected contains a counter, e.g. text0, text1, text2 etc, then the placeholder %%u should be used in the name of the psect at the position of the counter, e.g. text%%u. This will match any psect, regardless of the counter value. For example, to remap a C function, you could use: #pragma psect text%%u=lookupfunc int lookup(char ind) { ... Standard psects that make reference to a bank number are not using a counter and do not need the placeholder to match. For example, the redirect an uninitialized variable from bank 1 memory, use: #pragma psect bssBANK1=sharedObj int foobar; This pragma should not be used for any of the data psects (data or idata) that hold initialized variables. These psects must be assembled in a particular order and the use of this pragma to redirect some of their content will destroy this order. Use of this pragma with RAM-based psects that are intended to be linked into a particular RAM bank is acceptable, but the new psect must be linked into the same bank. Linking the new psect to a different bank may lead to code failure. This pragma affects the entire module in which it is located, regardless of the position of the pragma in the file. Any given psect should only be redirected once in a particular module. That is, you cannot redirect the standard psect for some of the module, then swap back to using the standard psect for the remainder of the source code. The pragma should typically be placed at the top of the source file. It is recommended that the code or variables to be separated be placed in a source file all to themselves so they are easily distinguished. To determine the psect in which the function or object is normally located, define the function or object in the usual way and without this pragma. Now check the assembly list file (see 4.4 “Assembly List Files”) to determine in which psect the function or object is normally positioned. Check either the assembly list file or the map file with the pragma in place to ensure that the mapping has worked as expected and that the function or variable has been linked at the address specified. Variables can also be placed at specific positions by making them absolute, see Section 3.5.4 “Absolute Variables”. The same is also true for functions. See 3.8.3 “Changing the Default Function Allocation”. The decision whether functions or variables should be positioned using absolutes or via the psect pragma should be based on the location requirements. Using absolute functions and variables is the easiest method, but only allows placement at an address which must be known prior to compilation. The psect pragma is more complex, but offers all the flexibility of the linker to position the new psect into memory. For example, you can specify that functions or variables reside at a fixed address, or that they be placed after other psects, or that the psect be placed anywhere in a compiler-defined or user-defined range of address. See Chapter 5. “Linker” for the features and options available when linking. See also 2.7.7 “-L-: Adjust Linker Options Directly” for information on controlling the linker from the driver or in MPLAB IDE. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 110  2010 Microchip Technology Inc. 3.15.3.6 THE #PRAGMA REGSUSED DIRECTIVE The #pragma regsused directive allows the programmer to indicate register usage for functions that will not be “seen” by the code generator, for example if they were written in assembly code. It has no effect when used with functions defined in C code, but in these cases the register usage of these functions can be accurately determined by the compiler and the pragma is not required. The compiler will determine only those registers and objects which need to be saved for an interrupt function defined and use of this pragma allows the code generator to also determine register usage for routines written in assembly code. The general form of the pragma is: #pragma regsused routineName registerList where routineName is the C equivalent name of the function or routine whose register usage is being defined, and registerList is a space-separated list of registers names, as shown in Table 3-13. Those registers not listed are assumed to be unused by the function or routine. The code generator may use any of these registers to hold values across a function call. Hence, if the routine does in fact use these registers, unreliable program execution may eventuate. The register names are not case sensitive and a warning will be produced if the register name is not recognized. A blank list indicates that the specified function or routine uses no registers. For example, a routine called _search is written in assembly code. In the C source, we may write: extern void search(void); #pragma regsused search wreg status fsr0 to indicate that this routine used the W register, STATUS and FSR0. 3.15.3.7 THE #PRAGMA SWITCH DIRECTIVE Normally, the compiler chooses how switch statements will be encoded to produce the smallest possible code size. The #pragma switch directive can be used to force the compiler to use a different coding strategy. The general form of the switch pragma is: #pragma switch switchType where switch_type is one of the available switch methods listed in Table 3-14. TABLE 3-13: VALID REGISTER NAMES Register Name Description fsr0, fsr0l, fsr0h Indirect data pointer fsr1, fsr1l, fsr1h Indirect data pointer wreg The working register status The status register TABLE 3-14: SWITCH TYPES switch type description speed Use the fastest switch method space Use the smallest code size method time Use a fixed delay switch method auto Use smallest code size method (default) C Language Features  2010 Microchip Technology Inc. DS51865B-page 111 Specifying the time option to the #pragma switch directive forces the compiler to generate the table look-up style switch method. The time taken to execute each case is the same, so this is useful where timing is an issue, e.g state machines. This pragma affects all subsequent code. The auto option may be used to revert to the default behavior. 3.15.3.8 THE #PRAGMA WARNING DIRECTIVE This pragma allows control over some of the compiler’s messages, such as warnings and errors. For full information on the massaging system employed by the compiler, see Section 2.6 “Compiler Messages”. 3.15.3.8.1 The Warning Disable Pragma Some warning messages can be disabled by using the warning disable pragma. This pragma will only affect warnings that are produced by the parser or the code generator, i.e. errors directly associated with C code. The position of the pragma is only significant for the parser, i.e. a parser warning number may be disabled for one section of the code to target specific instances of the warning. Specific instances of a warning produced by the code generator cannot be individually controlled and the pragma will remain in force during compilation of the entire module. The state of those warnings which have been disabled can preserved and recalled using the warning push and warning pop pragmas. Pushes and pops can be nested to allow a large degree of control over the message behavior. The following example shows the warning associated with assigning the address of a const object to a pointer to non-const objects. Such code normally produces warning number 359. int readp(int * ip) { return *ip; } const int i = 'd'; void main(void) { unsigned char c; #pragma warning disable 359 readp(&i); #pragma warning enable 359 } This same affect would be observed using the following code. #pragma warning push #pragma warning disable 359 readp(&i); #pragma warning pop Here the state of the messaging system is saved by the warning push pragma. Warning 359 is disabled, then after the source code which triggers the warning, the state of the messaging system is retrieved by using the warning pop pragma. 3.15.3.8.2 The Warning Error/warning Pragma It is also possible to change the type of some messages. direct (deprecated) Use a fixed delay switch method simple (deprecated) Sequential xor method TABLE 3-14: SWITCH TYPES (CONTINUED) switch type description HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 112  2010 Microchip Technology Inc. This is only possible by the use of the warning pragma and only affects messages generated by the parser or code generator. The position of the pragma is only significant for the parser, i.e. a parser message number may have its type changed for one section of the code to target specific instances of the message. Specific instances of a message produced by the code generator cannot be individually controlled and the pragma will remain in force during compilation of the entire module. The following shows the warning produced in the previous example being converted to an error for the instance in the function main(). void main(void) { unsigned char c; #pragma warning error 359 readp(&i); } Compilation of this code would result in an error, not the usual warning. The error will force compilation to cease after the current module has concluded, or immediately if the maximum error count has been reached. 3.16 LINKING PROGRAMS The compiler will automatically invoke the linker unless the compiler has been requested to stop after producing an intermediate file. The linker will run with options that are obtained from the command-line driver. These options specify the memory of the device and how the psects should be placed in the memory. No linker scripts are used. The linker options passed to the linker can be adjusted by the user, but this is only required in special circumstances. See Section 2.7.7 “-L-: Adjust Linker Options Directly” for more information.) The linker creates a map file which details the memory assigned to psects and some objects within the code. The map file is the best place to look for memory information. See Section 5.4 “Map Files” for a detailed explanation of the detailed information in this file. 3.16.1 Replacing Library Modules The HI-TECH C compiler comes with a librarian, LIBR, which allows you to unpack a library file and replace modules with your own modified versions. See Section 6.2 “Librarian”. However, you can easily replace a library module that is linked into your program without having to do this. If you add to your project a source file which contains the definition for a routine with the same name as a library routine, then the library routine will be replaced by your routine. This works due to the way the compiler scans source and library files. When trying to resolve a symbol (a function name, or variable name, for example) the compiler first scans all the source modules for the definition. Only if it cannot resolve the symbol in these files does it then search the library files. If the symbol is defined in a source file, the compiler will never actually search the libraries for this symbol and no error will result even if the symbol was present in the library files. This may not be true if a symbol is defined twice in source files and an error may result if there is a conflict in the definitions. All libraries are written C code, and the p-code libraries that contain these library routines are actually passed to the code generator, not the linker, but both these applications work in the way described above in resolving library symbols. C Language Features  2010 Microchip Technology Inc. DS51865B-page 113 You cannot replace a C library function with an equivalent written in assembly code using the above method. If this is required, you will need to use the librarian to edit or create a new library file. 3.16.2 Signature Checking The compiler automatically produces signatures for all functions. A signature is a 16-bit value computed from a combination of the function’s return data type, the number of its parameters and other information affecting the calling sequence for the function. This signature is output in the object code of any function referencing or defining the function. At link time the linker will report any mismatch of signatures. HI-TECH C is only likely to issue a mismatch error from the linker when the routine is either a precompiled object file or an assembly routine. Other function mismatches are reported by the code generator. It is sometimes necessary to write assembly language routines which are called from C using an extern declaration. Such assembly language functions should include a signature which is compatible with the C prototype used to call them. The simplest method of determining the correct signature for a function is to write a dummy C function with the same prototype and check the assembly list file using the --ASMLIST option (see Section 2.7.17 “--ASMLIST: Generate Assembler List Files”). For example, suppose you have an assembly language routine called _widget which takes two int arguments and returns a char value. The prototype used to call this function from C would be: extern char widget(int, int); Where a call to _widget is made in the C code, the signature for a function with two int arguments and a char return value would be generated. In order to match the correct signature, the source code for widget needs to contain an assembler SIGNAT directive which defines the same signature value. To determine the correct value, you would write the following code: char widget(int arg1, int arg2) { } The resultant assembler code seen in the assembly list file includes the following line: SIGNAT _widget,8249 The SIGNAT directive tells the assembler to include a record in the .obj file which associates the value 8249 with symbol _widget. The value 8249 is the correct signature for a function with two int arguments and a char return value. If this directive is copied into the assembly source file which contains the _widget code, it will associate the correct signature with the function and the linker will be able to check for correct argument passing. If a C source file contains the declaration: extern char widget(long); then a different signature will be generated and the linker will report a signature mis-match which will alert you to the possible existence of incompatible calling conventions. 3.16.3 Linker-Defined Symbols The linker defines some special symbols that can be used to determine where some psects where linked in memory. These symbols can be used in code, if required. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 114  2010 Microchip Technology Inc. The link address of a psect can be obtained from the value of a global symbol with name __Lname where name is the name of the psect. For example, __LbssBANK0 is the low bound of the bssBANK0 psect. The highest address of a psect (i.e. the link address plus the size) is represented by the symbol __Hname. If the psect has different load and link addresses, the load start address is represented by the symbol __Bname. Not all psects are assigned these symbols, in particular those that are not placed in memory by a -P linker option (not driver option). See Section 5.2.18 “-Pspec”. Psect names may change from one device to another. Assembly code can use these symbol by globally declaring them, for example: GLOBAL __Lidata HI-TECH C® FOR PIC10/12/16 USER’S GUIDE  2010 Microchip Technology Inc. DS51865B-page 115 Chapter 4. Macro Assembler The macro assembler included with HI-TECH C PRO for PIC10/12/16 MCU Family assembles source files for PIC 10/12/14/16/17 MCUs. This chapter describes the usage of the assembler and the directives (assembler pseudo-ops and controls) accepted by the assembler in the source files. Although the term “assembler” is almost universally used to describe the tool which converts human-readable mnemonics into machine code, both “assembler” and “assembly” are used to describe the source code which such a tool reads. The latter is more common and is used in this manual to describe the language. Thus you will see the terms assembly language (or just assembly), assembly listing and etc, but assembler options, assembler directive and assembler optimizer. 4.1 ASSEMBLER USAGE The assembler is called ASPIC and is available to run on Windows, Linux and Mac OS X systems. Note that the assembler will not produce any messages unless there are errors or warnings — there are no “assembly completed” messages. Typically the command-line driver, PICC, is used to invoke the assembler as it can be passed assembler source files as input, however the options for the assembler are supplied here for instances where the assembler is being called directly, or when they are specified using the command-line driver option --SETOPTION, see Section 2.7.53 “--SETOPTION: Set The Command-line Options for Application”. The usage of the assembler is similar under all of available operating systems. All command-line options are recognized in either upper or lower case. The basic command format is shown: ASPIC [ options ] file files is a space-separated list of one or more assembler source files. Where more than one source file is specified, the assembler treats them as a single module, i.e. a single assembly will be performed on the concatenation of all the source files specified. The files must be specified in full, no default extensions or suffixes are assumed. options is an optional space-separated list of assembler options, each with a minus sign - as the first character in the case of single letter options, or two minus signs in the case of multi-letter options. The assembler options must be specified on the command line before any files. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 116  2010 Microchip Technology Inc. A full list of possible options is given in Table 4-1, and a full description of each option follows. 4.2 OPTIONS The command line options recognized by ASPIC are described in the followings sections. 4.2.1 -A: Generate Assembly File An assembler file will be produced if this option is used rather than the usual object file format. This is useful when checking the optimized assembler produced using the -O optimization option. By default the output file will an extension .opt, unless the -Ooutfile output option is used to specify another name. 4.2.2 -C: Produce Cross Reference File A cross reference file will be produced when this option is used. The cross reference file, called srcfile.crf, where srcfile is the base portion of the first source file name, will contain raw cross reference information. The cross reference utility CREF must then be run to produce the formatted cross reference listing. See Section 6.4 “Cref” for more information on this application. TABLE 4-1: ASPIC COMMAND-LINE OPTIONS Option Meaning Default -A Produce assembler output Produce object code -C Produce cross-reference file No cross reference -Cchipinfo Define the chipinfo file dat\picc.ini -E[file | digit] Set error destination/format -Flength Specify listing page length 66 -H Output HEX values for constants Decimal values -I List macro expansions Don’t list macros -L[listfile ] Produce listing No listing -N Disable merging optimizations Merging optimizations enabled -O Perform optimization No optimization -Ooutfile Specify object name srcfile.obj -R Specify non-standard ROM -Twidth Specify listing page width 80 -V Produce line number info No line numbers -VER=version Specify full version information for list file title -Wlevel Set warning level threshold 0 -X No local symbols in OBJ file --CHIP=device Specify device name --DISL=list Specify disabled messages No message disabled --EDF=path Specify message file location --EMAX=number Specify maximum number of errors 10 --OPT=optimization Specify optimization type -VER Print version number and stop Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 117 4.2.3 -C: Specify Chip Info File Specify the chipinfo file to use. The chipinfo file is called picc.ini and can be found in the dat directory in the compiler’s installation directory. This file specifies information about the currently selected device. 4.2.4 -E: Specify Error Format/File The default format for an error message is in the form: filename: line: message where the error of type message occurred on line line of the file filename. The -E option with no argument will make the assembler use an alternate format for error and warning messages. Specifying a filename as argument will force the assembler to direct error and warning messages to a file with the name specified. 4.2.5 -F: Specify Page Length By default the assembly listing format is pageless, i.e. the assembler listing output is continuous. The output may be formatted into pages of varying lengths. Each page will begin with a header and title, if specified. The -F option allows a page length to be specified. A zero value of length implies pageless output. The length is specified in a number of lines. 4.2.6 -H: Print Hexadecimal Constant This option specifies that output constants should be shown as hexadecimal values rather than decimal values. This option affects both the assembly list file, as well as assembly output, when requested. 4.2.7 -I: List Macro Expansions This option forces listing of macro expansions and unassembled conditionals which would otherwise be suppressed by a NOLIST assembler control, see Section 4.3.10 “Assembler Controls”. The -L option is still necessary to produce an actual listing output. 4.2.8 -L: Generate an Assembly Listing This option requests the generation of an assembly listing file. If listfile is specified then the listing will be written to that file, otherwise it will be written to the standard output. This option is applied if compiling using PICC, the command-line driver and the --ASMLIST driver option, see Section 2.7.17 “--ASMLIST: Generate Assembler List Files”. 4.2.9 -O: Optimize assembly This requests the assembler to perform optimization on the assembly code. Note that the use of this option slows the assembly process down, as the assembler must make an additional pass over the input code. Debug information for assembler code generated from C source code may become unreliable in debuggers when this option is used. This option can be applied if compiling using PICC, the command-line driver and the --OPT driver option, see Section 2.7.42 “--OPT: Invoke Compiler Optimizations”. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 118  2010 Microchip Technology Inc. 4.2.10 -O: Specify Output File By default the assembler determines the name of the object file to be created by stripping any suffix or extension from the first source filename and appending .obj. The -O option allows the user to override the default filename and specify a new name for the object file. 4.2.11 -T: Specify Listing Page Width This option allows specification of the assembly list file page width, in characters. width should be a decimal number greater than 41. The default width is 80 characters. 4.2.12 -V: Produce Assembly Debug Information This option will include line number and filename information in the object file produced by the assembler. Such information may be used by debuggers. Note that the line numbers will correspond with assembler code lines in the assembler file. This option should not be used when assembling an assembly file produced by the code generator. In that case, debug information should relate back to the original C source, not the intermediate assembly code. 4.2.13 -VER:Specify Version Information This option allows the full version information, including optional text to indicate beta builds or release candidate builds, to be passed to the assembler. This information is only used in the title of the assembly list file and is not reflected in the output to the --VER option. 4.2.14 -X: Strip Local Symbols The object file created by the assembler contains symbol information, including local symbols, i.e. symbols that are neither public or external. The -X option will prevent the local symbols from being included in the object file, thereby reducing the file size. description 4.2.15 --CHIP: Specify Device Name This option defines the processor which is being used. The processor type can also be indicated by use of the PROCESSOR directive in the assembler source file, see Section 4.3.9.19 “PROCESSOR”. You can also add your own processors to the compiler via the compiler’s chipinfo file. This option is applied if compiling using PICC, the command-line driver and the --CHIP driver option, see Section 2.7.20 “--CHIP: Define Processor”. 4.2.16 --DISL: Disable Messages This option is mainly used by the command-line driver, PICC, to disable particular message numbers. It takes a comma-separate list of message numbers that will be disabled during compilation. This option is applied if compiling using PICC, the command-line driver and the --MSGDISABLE driver option, see Section 2.7.37 “--MSGDISABLE: Disable Warning Messages”. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 119 4.2.17 --EDF: Set Message File Path This option is mainly used by the command-line driver, PICC, to specify the path of the message description file. The default file is located in the dat directory in the compiler’s installation directory. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 4.2.18 --EMAX: Specify Maximum Number of Errors This option is mainly used by the command-line driver, PICC, to specify the maximum number of errors that can be encountered before the assembler terminates. The default number is 10 errors. This option is applied if compiling using PICC, the command-line driver and the --ERRORS driver option, see Section 2.7.28 “--ERRORS: Maximum Number of Errors”. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 4.2.19 --OPT: Specify Optimization Type This option complements the assembler -O option and indicates specific information about optimizations required. The suboptions: speed, space and debug may be specified to indicate preferences related to procedural abstraction. Abstraction is enabled when the space option is set; disabled when speed is set. The debug suboption limits the application of some optimizations which otherwise may severely corrupt debug information used by debuggers. 4.2.20 --VER: Print Version Number This option printed information relating to the version and build of the assembler. The assembler will terminate after processing this option, even if other options and files are present on the command line. 4.3 HI-TECH C ASSEMBLY LANGUAGE The source language accepted by the macro assembler, ASPIC, is described below. All opcode mnemonics and operand syntax are specific to the PIC10, PIC12, PIC14000, PIC16 and PIC17 devices, include the enhanced mid-range devices. Although the PIC17 family instruction set is supported at the assembler level, the code generator cannot produce code for these devices so no C projects can target these devices. Additional mnemonics and assembler directives are documented in this section. 4.3.1 Assembler Format Deviations The HI-TECH PICC assembler uses a slightly modified form of assembly language to that specified by the Microchip data sheets. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 120  2010 Microchip Technology Inc. 4.3.1.1 DESTINATION LOCATION Certain PIC instructions use the operands “,0” or “,1” to specify the destination for the result of that operation. ASPIC uses the more-readable operands “,w” and “,f” to specify the destination register. The W register is selected as the destination when using the “,w” operand, and the file register is selected when using the “,f” operand or if no destination operand is specified. The case of the letter in the destination operand in not important. The numerical destination operands cannot be used with ASPIC. 4.3.1.2 LONG JUMPS AND CALLS The assembler also recognizes several mnemonics which expand into regular PIC MCU assembly instructions. The mnemonics are FCALL and LJMP. These instructions expand into regular CALL and GOTO instructions respectively, but also include the instructions necessary to set the bits in PCLATH (for mid-range devices), or STATUS (for baseline devices) when the destination is in another page of program memory. These additional mnemonics should be used where possible as they make assembler code independent of the final position of the routines that are to be executed. If the call or jump is determined to be within the current page, the additional code to set the PCLATH bits may be optimized away. The following example shows an FCALL instruction in the assembly list file. You can see that the FCALL instruction has expanded to five instructions. In this example there are two bit instructions which set/clear bits in the PCLATH register. Bits are also set/cleared in this register after the call to reselect the page which was selected before the fcall. 13 0079 3021 movlw 33 14 007A 120A 158A 2000 fcall _phantom 120A 118A 15 007F 3400 retlw 0 4.3.2 Statement Formats Legal statement formats are shown in Table Section Table 4-2: “ASPIC statement formats”. The label field is optional and, if present, should contain one identifier. A label may appear on a line of its own, or precede a mnemonic as shown in the second format. The third format is only legal with certain assembler directives, such as MACRO, SET and EQU. The name field is mandatory and should also contain one identifier. If the assembly file is first processed by the C preprocessor, see Section 2.7.11 “-P: Preprocess Assembly Files”, then it may also contain lines that form valid preprocessor directives. See Section 3.15.1 “Preprocessor Directives” for more information on the format for these directives. There is no limitation on what column or part of the line in which any part of the statement should appear. TABLE 4-2: ASPIC STATEMENT FORMATS Format # Feild1 Field2 Field3 Field4 Format 1 label: Format 2 label: mnemonic operands ; comment Format 3 name pseudo-op operands ; comment Format 4 ; comment only Format 5 empty line Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 121 4.3.3 Characters The character set used is standard 7 bit ASCII. Alphabetic case is significant for identifiers, but not mnemonics and reserved words. Tabs are treated as equivalent to spaces. 4.3.3.1 DELIMITERS All numbers and identifiers must be delimited by white space, non-alphanumeric characters or the end of a line. 4.3.3.2 SPECIAL CHARACTERS There are a few characters that are special in certain contexts. Within a macro body, the character & is used for token concatenation. To use the bitwise & operator within a macro body, escape it by using && instead. In a macro argument list, the angle brackets < and > are used to quote macro arguments. 4.3.4 Comments An assembly comment is initiated with a semicolon that is not part of a string or character constant. If the assembly file is first processed by the C preprocessor, see Section 2.7.11 “-P: Preprocess Assembly Files”, then the file may also contain C or C++ style comments using the standard /* ... */ and // syntax. 4.3.4.1 SPECIAL COMMENT STRINGS Several comment strings are appended to assembler instructions by the code generator. These are typically used by the assembler optimizer. The comment string ;volatile is used to indicate that the memory location being accessed in the commented instruction is associated with a variable that was declared as volatile in the C source code. Accesses to this location which appear to be redundant will not be removed by the assembler optimizer if this string is present. This comment string may also be used in assembler source to achieve the same effect for locations defined and accessed in assembly code. 4.3.5 Constants 4.3.5.1 NUMERIC CONSTANTS The assembler performs all arithmetic with signed 32-bit precision. The default radix for all numbers is 10. Other radices may be specified by a trailing base specifier as given in Table 4-3. Hexadecimal numbers must have a leading digit (e.g. 0ffffh) to differentiate them from identifiers. Hexadecimal digits are accepted in either upper or lower case. Note that a binary constant must have an upper case B following it, as a lower case b is used for temporary (numeric) label backward references. TABLE 4-3: ASPIC NUMBERS AND BASES Radix Format Binary Digits 0 and 1 followed by B Octal Digits 0 to 7 followed by O, Q, o or q Decimal Digits 0 to 9 followed by D, d or nothing Hexadecimal Digits 0 to 9, A to F preceded by Ox or followed by H or h HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 122  2010 Microchip Technology Inc. In expressions, real numbers are accepted in the usual format, and are interpreted as IEEE 32-bit format. 4.3.5.2 CHARACTER CONSTANTS AND STRINGS A character constant is a single character enclosed in single quotes ’. Multi-character constants, or strings, are a sequence of characters, not including carriage return or newline characters, enclosed within matching quotes. Either single quotes ’ or double quotes " maybe used, but the opening and closing quotes must be the same. 4.3.6 Identifiers Assembly identifiers are user-defined symbols representing memory locations or numbers. A symbol may contain any number of characters drawn from the alphabetics, numerics and the special characters dollar, $, question mark, ? and underscore, _. The first character of an identifier may not be numeric. The case of alphabetics is significant, e.g. Fred is not the same symbol as fred. Some examples of identifiers are shown here: An_identifier an_identifier an_identifier1 $ ?$_12345 4.3.6.1 SIGNIFICANCE OF IDENTIFIERS Users of other assemblers that attempt to implement forms of data typing for identifiers should note that this assembler attaches no significance to any symbol, and places no restrictions or expectations on the usage of a symbol. The names of psects (program sections) and ordinary symbols occupy separate, overlapping name spaces, but other than this, the assembler does not care whether a symbol is used to represent bytes, words or sports cars. No special syntax is needed or provided to define the addresses of bits or any other data type, nor will the assembler issue any warnings if a symbol is used in more than one context. The instruction and addressing mode syntax provide all the information necessary for the assembler to generate correct code. 4.3.6.2 ASSEMBLER-GENERATED IDENTIFIERS Where a LOCAL directive is used in a macro block, the assembler will generate a unique symbol to replace each specified identifier in each expansion of that macro. These unique symbols will have the form ??nnnn where nnnn is a 4 digit number. The user should avoid defining symbols with the same form. 4.3.6.3 LOCATION COUNTER The current location within the active program section is accessible via the symbol $. This symbol expands to the address of the currently executing instruction (which is different to the address contained in the program counter when executing this instruction). Thus: GOTO $ will represent code that will jump to itself and form an endless loop. By using this symbol and an offset, a relative jump destination can be specified. Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 123 The address represented by $ is a word address (baseline and Mid-Range devices use program memory which is word-addressable) and thus any offset to this symbol represents a number of instructions. For example: GOTO $+2 MOVLW 8 MOVWF _foo will skip one instruction. 4.3.6.4 REGISTER SYMBOLS Code in assembly modules may gain access to the special function registers by including pre-defined assembly header files. The appropriate file can be included by add the line: #include to the assembler source file. Note that the file must be included using a C pre-processor directive and hence the option to pre-process assembly files must be enabled when compiling, see Section 2.7.11 “-P: Preprocess Assembly Files”. This header file contains appropriate commands to ensure that the header file specific for the target device is included into the source file. These header files contain EQU declarations for all byte or multi-byte sized registers and #define macros for named bits within byte registers. 4.3.6.5 SYMBOLIC LABELS A label is a symbolic alias which is assigned a value equal to the current address within the current psect. Labels are not assigned a value until link time. A label definition consists of any valid assembly identifier and optionally followed by a colon, :. The definition may appear on a line by itself or be positioned before a statement. Here are two examples of legitimate labels interspersed with assembly code. frank: MOVLW 1 GOTO fin simon44: CLRF _input Here, the label frank will ultimately be assigned the address of the MOVLW instruction, and simon44 the address of the CLRF instruction. Regardless of how they are defined, the assembler list file produced by the assembler will always show labels on a line by themselves. Note that the colon following the label is optional, but is recommended. Symbols which are not interpreted in any other way are assumed to be labels. Mistyped assembler instructions can sometimes be treated as labels without an error message being issued. Thus the code: mistake: MOVLW 23h MOVWF 37h REUTRN ; oops defines a symbol called REUTRN, which was intended to be the RETURN instruction. Labels may be used (and are preferred) in assembly code rather than using an absolute address. Thus they can be used as the target location for jump-type instructions or to load an address into a register. Like variables, labels have scope. By default, they may be used anywhere in the module in which they are defined. They may be used by code before their definition. To make a label accessible in other modules, use the GLOBAL directive. See Section 4.3.9.1 “GLOBAL” for more information. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 124  2010 Microchip Technology Inc. 4.3.7 Expressions The operands to instructions and directives are comprised of expressions. Expressions can be made up of numbers, identifiers, strings and operators. Operators can be unary (one operand, e.g. not) or binary (two operands, e.g. +). The operators allowable in expressions are listed in Table 4-4. The usual rules governing the syntax of expressions apply. The operators listed may all be freely combined in both constant and relocatable expressions. The HI-TECH linker permits relocation of complex expressions, so the results of expressions involving relocatable identifiers may not be resolved until link time. TABLE 4-4: ASPIC OPERATORS Operator Purpose Example * Multiplication MOVLW 4*33,w + Addition BRA $+1 - Subtraction DB 5-2 / Division MOVLW 100/4 = or eq Equality IF inp eq 66 > or gt Signed greater than IF inp > 40 >= or ge Signed greater than or equal to IF inp ge 66 < or lt Signed less than IF inp < 40 <= or le Signed less than or equal to IF inp le 66 <> or ne Signed not equal to IF inp <> 40 low Low byte of operand MOVLW low(inp) high High byte of operand MOVLW high(1008h) highword High 16 bits of operand DW highword(inp) mod Modulus MOVLW 77mod4 & Bitwise AND CLRF inp&0ffh ^ Bitwise XOR (exclusive or) MOVF inp^80,w | Bitwise OR MOVF inp|1,w not Bitwise complement MOVLW not 055h,w << or shl Shift left DB inp>>8 >> or shr Shift right MOVLW inp shr 2,w rol Rotate left DB inp rol 1 ror Rotate right DB inp ror 1 float24 24-bit version of real operand DW float24(3.3) nul Tests if macro argument is null Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 125 4.3.8 Program Sections Program sections, or psects, are simply a section of code or data. They are a way of grouping together parts of a program (via the psect’s name) even though the source code may not be physically adjacent in the source file, or even where spread over several modules. A psect is identified by a name and has several attributes. The PSECT assembler directive is used to define a psect. It takes as arguments a name and an optional comma-separated list of flags. See Section 3.10.1 “Compiler-generated Psects” for a list of all psects that the code generator defines. Chapter 5. “Linker” has more information on the operation of the linker and on options that can be used to control psect placement in memory. The assembler associates no significance to the name of a psect and the linker is also not aware of which psects are compiler-generated or which are user-defined. Unless defined as abs (absolute), psects are relocatable. The following is an example showing some executable instructions being placed in the mytext psect, and space being reserved in the mybss psect. Neither of these psects are compiler defined. PSECT mytext,class=CODE,delta=2 adjust: GOTO clear_fred increment: INCF _fred PSECT mybss,class=BANK0,space=1 fred: DS 2 PSECT mytext,class=CODE,delta=2 clear_fred: CLRF _fred+1 RETURN Note that even though the two blocks of code in the mytext psect are separated by a block in the mybss psect, the two mytext psect blocks will be contiguous when loaded by the linker. In other words, the INCF _fred instruction will be followed by the clrf instruction in the final output. The actual location in memory of the mytext and mybss psects will be determined by the linker. Code or data that is not explicitly placed into a psect will become part of the default (unnamed) psect. 4.3.9 Assembler Directives Assembler directives, or pseudo-ops, are used in a similar way to instruction mnemonics. With the exception of PAGESEL and BANKSEL, these directives do not generate any output, or may generate non-executable output, i.e. data bytes. The directives are listed in Table 4-5, and are detailed below in the following sections. TABLE 4-5: ASPIC ASSEMBLER DIRECTIVES Directive Purpose GLOBAL Make symbols accessible to other modules or allow reference to other modules’ symbols END End assembly PSECT Declare or resume program section ORG Set location counter within current psect EQU Define symbol value SET Define or re-define symbol value HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 126  2010 Microchip Technology Inc. 4.3.9.1 GLOBAL The GLOBAL directive declares a list of comma-separated symbols. If the symbols are defined within the current module, they are made public. If the symbols are not defined in the current module, they are made references to public symbols defined in external modules. Thus to use the same symbol in two modules the GLOBAL directive must be used at least twice: once in the module that defines the symbol to make that symbol public, and again in the module that uses the symbol to link in with the external definition. For example: GLOBAL lab1,lab2,lab3 4.3.9.2 END The END directive is optional, but if present should be at the very end of the program. It will terminate the assembly and not even blank lines should follow this directive. If an expression is supplied as an argument, that expression will be used to define the entry point of the program. This is stored in a start record in the object file produced by the assembler. Whether this is of any use will depend on the linker. DB Define constant byte(s) DW Define constant word(s) DS Reserve storage DABS Define absolute storage IF Conditional assembly ELSIF Alternate conditional assembly ELSE Alternate conditional assembly ENDIF End conditional assembly FNADDR Inform the linker that a function may be indirectly called FNARG Inform the linker that evaluation of arguments for one function requires calling another FNBREAK Break call graph links FNCALL Inform the linker that one function calls another FNCONF Supply call graph configuration information for the linker FNINDIR Inform the linker that all functions with a particular signature may be indirectly called FNROOT Inform the linker that a function is the “root” of a call graph FNSIZE Inform the linker of argument and local variable for a function MACRO Macro definition ENDM End macro definition LOCAL Define local tabs ALIGN Align output to the specified boundary BANKSEL Generate code to select bank of operand PAGESEL Generate set/clear instruction to set PCLATH bits for this page PROCESSOR Define the particular chip for which this file is to be assembled. REPT Repeat a block of code n times IRP Repeat a block of code with a list IRPC Repeat a block of code with a character list SIGNAT Define function signature TABLE 4-5: ASPIC ASSEMBLER DIRECTIVES (CONTINUED) Directive Purpose Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 127 The default runtime startup code defined by the compiler will contain an END directive with a start address. As only one start address can be specified for each project, you normally do not need to define this address, but may use the END directive with no entry point in any file. For example: END start_label ;defines the entry point or END ;do not define entry point 4.3.9.3 PSECT The PSECT directive declares or resumes a program section. It takes as argument a name and, optionally, a comma-separated list of flags. The allowed flags are listed in Table 4-6 and specify attributes of the psect. Once a psect has been declared it may be resumed later by another PSECT directive, however the flags need not be repeated and will be propagated from the earlier declaration. If two PSECT directives are encountered with contradicting flags, then an error will be generated. Some examples of the use of the PSECT directive follow: PSECT fred PSECT bill,size=100h,global PSECT joh,abs,ovrld,class=CODE,delta=2 4.3.9.3.1 Abs The abs flag defines the current psect as being absolute, i.e. it is to start at location 0. This does not mean that this module’s contribution to the psect will start at 0, since other modules may contribute to the same psect. See also Section 4.3.9.3.8 “Ovrld”. An abs-flagged psect is not relocatable and an error will result if a linker option is issued that attempts to place such a psect at any location. 4.3.9.3.2 Bit The bit flag specifies that a psect holds objects that are 1 bit long. Such psects will have a scale value of 8 to indicate that there are 8 addressable units to each byte of storage and all addresses associated with this psect will be bit address, not byte addresses. The scale value is indicated in the map file, see Section 5.4 “Map Files”. TABLE 4-6: PSECT FLAGS Flag Meaning abs Psect is absolute bit Psect holds bit objects class=name Specify class name for psect delta=size Size of an addressing unit global Psect is global (default) limit=address Upper address limit of psect local Psect is not global ovrld Psect will overlap same psect in other modules pure Psect is to be read-only reloc=boundary Start psect on specified boundary size=max Maximum size of psect space=area Represents area in which psect will reside with=psect Place psect in the same page as specified psect HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 128  2010 Microchip Technology Inc. 4.3.9.3.3 Class The class flag specifies a corresponding linker class name for this psect. A class is a range of addresses in which psects may be placed. Class names are used to allow local psects to be located at link time, since they cannot always be referred to by their own name in a -P linker option (as would be the case if there are more than one local psect with the same name). Class names are also useful where psects need only be positioned anywhere within a range of addresses rather than at a specific address. The association of a class with a psect that you have defined typically means that you do not need to supply a custom linker option to place it in memory. See Section 5.2.1 “-Aclass =low-high,...” for information on how linker classes are defined. 4.3.9.3.4 Delta The delta flag defines the size of the addressing unit. In other words, the number of data bytes which are associated with each address. With PIC Mid-Range and baseline devices, the program memory space is word addressable, hence psects in this space must use a delta of 2. That is to say, each address in program memory requires 2 bytes of data in the HEX file to define their contents. Thus addresses in the HEX file will not match addresses in the program memory. The data memory space on these devices is byte addressable, hence psects in this space must use a delta of 1. This is the default delta value. The redefinition of a psect with conflicting delta values can lead to phase errors being issued by the assembler. 4.3.9.3.5 Global A psect defined as global will be combined with other global psects with the same name at link time. Psects are grouped from all modules being linked. Psects are considered global by default, unless the local flag is used. 4.3.9.3.6 Limit The limit flag specifies a limit on the highest address to which a psect may extend. If this limit is exceeded when it is positioned in memory, an error will be generated. 4.3.9.3.7 Local A psect defined as local will not be combined with other local psects from other modules at link time, even if there are others with the same name. Where there are two local psects in the one module, they reference the same psect. A local psect may not have the same name as any global psect, even one in another module. 4.3.9.3.8 Ovrld A psect defined as ovrld will have the contribution from each module overlaid, rather than concatenated at link time. This flag in combination with the abs flag (see Section 4.3.9.3.1 “Abs”) defines a truly absolute psect, i.e. a psect within which any symbols defined are absolute. 4.3.9.3.9 Pure The pure flag instructs the linker that this psect will not be modified at runtime and may therefore, for example, be placed in ROM. This flag is of limited usefulness since it depends on the linker and target system enforcing it. Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 129 4.3.9.3.10 Reloc The reloc flag allows specification of a requirement for alignment of the psect on a particular boundary. For example the flag reloc=100h would specify that this psect must start on an address that is a multiple of 100h. 4.3.9.3.11 Size The size flag allows a maximum size to be specified for the psect, e.g. size=100h. This will be checked by the linker after psects have been combined from all modules. 4.3.9.3.12 Space The space flag is used to differentiate areas of memory which have overlapping addresses, but which are distinct. Psects which are positioned in program memory and data memory have a different space value to indicate that the program space address 0, for example, is a different location to the data memory address 0. On all PIC devices, program memory uses a space value of 0, and data space memory uses a space of 1. Devices which have a banked data space do not use different space values to identify each bank. A full address which includes the bank number is used for objects in this space and so each location can be uniquely identified. For example a device with a bank size of 0x80 bytes will uses address 0 to 0x7F to represent objects in bank 0, and then addresses 0x80 to 0xFF to represent objects in bank 1, etc. 4.3.9.3.13 With The with flag allows a psect to be placed in the same page with another psect. For example the flag with=text will specify that this psect should be placed in the same page as the text psect. The term withtotal refers to the sum of the size of each psect that is placed "with" other psects. 4.3.9.4 ORG The ORG directive changes the value of the location counter within the current psect. This means that the addresses set with ORG are relative to the base address of the psect, which is not determined until link time. The argument to ORG must be either an absolute value, or a value referencing the current psect. In either case the current location counter is set to the value determined by the argument. It is not possible to move the location counter backward. For example: ORG 100h will move the location counter to the beginning of the current psect plus 100h. The actual location will not be known until link time. In order to use the ORG directive to set the location counter to an absolute value, the directive must be used from within an absolute, overlaid psect. For example: PSECT absdata,abs,ovrld ORG 50h ;this is guaranteed to reside at address 50h Note: The much-abused ORG directive does not move the location counter to the absolute address you specify. Only if the psect in which this directive is placed is absolute and overlaid will the location counter be moved to the address specified. To place objects at a particular address, place them in a psect of their own and link this at the required address using the linkers -P option, see Section 5.2.18 “-Pspec”. The ORG directive is not commonly required in programs. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 130  2010 Microchip Technology Inc. 4.3.9.5 EQU This pseudo-op defines a symbol and equates its value to an expression. For example thomas EQU 123h The identifier thomas will be given the value 123h. EQU is legal only when the symbol has not previously been defined. See also Section 4.3.9.6 “SET” which allows for redefinition of values. This directive performs a similar function to the preprocessor’s #define directive, see Section 3.15.1 “Preprocessor Directives”. 4.3.9.6 SET This pseudo-op is equivalent to EQU (Section 4.3.9.5 “EQU”) except that allows a symbol to be re-defined without error. For example: thomas SET 0h This directive performs a similar function to the preprocessor’s #define directive, see Section 3.15.1 “Preprocessor Directives”. 4.3.9.7 DB The DB directive is used to initialize storage as bytes. The argument is a comma-separated list of expressions, each of which will be assembled into one byte and assembled into consecutive memory locations. Examples: alabel: DB ’X’,1,2,3,4, Note that because the size of an address unit in the program memory is 2 bytes (see Section 4.3.9.3.4 “Delta”), the DB pseudo-op will initialise a word with the upper byte set to zero. So the above example will define bytes padded to the following words. 0058 0001 0002 0003 0004 4.3.9.8 DW The DW directive operates in a similar fashion to DB, except that it assembles expressions into words. Example: DW -1, 3664h, ’A’’ 4.3.9.9 DS This directive reserves, but does not initialize, memory locations. The single argument is the number of bytes to be reserved. This directive is typically used to reserve memory location for RAM-based objects in the data memory. If used in a psect linked into the program memory, it will move the location counter, but not place anything in the HEX file output. Note that because the size of an address unit in the program memory is 2 bytes (see Section 4.3.9.3.4 “Delta”), the DS pseudo-op will actually reserve an entire word. A variable is typically defined by using a label and then the DS directive to reserve locations at the label location. Examples: alabel: DS 23 ;Reserve 23 bytes of memory xlabel: DS 2+3 ;Reserve 5 bytes of memory Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 131 4.3.9.10 DABS This directive allows one or more bytes of memory to be reserved at the specified address. The general form of the directive is: DABS memorySpace, address, bytes where memorySpace is a number representing the memory space in which the reservation will take place, address is the address at which the reservation will take place, and bytes is the number of bytes that is to be reserved. This directive differs to the DS directive in that it can be used to reserve memory at any location, not just within the current psect. Indeed, these directives can be placed anywhere in the assembly code and do not contribute to the currently selected psect in any way. The memory space number is the same as the number specified with the space flag option to psects (see Section 4.3.9.3.12 “Space”). The code generator issues a DABS directive for every user-defined absolute C variable, or for any variables that have been allocated an address by the code generator. The linker reads this DABS-related information from object files and will ensure that the reserved address are not used for other memory placement. 4.3.9.11 IF, ELSIF, ELSE AND ENDIF These directives implement conditional assembly. The argument to IF and ELSIF should be an absolute expression. If it is non-zero, then the code following it up to the next matching ELSE, ELSIF or ENDIF will be assembled. If the expression is zero then the code up to the next matching ELSE or ENDIF will be skipped. These directives do not implement a runtime conditional statement in the same way that the C statement if() does; they are evaluated at compile time. At an ELSE the sense of the conditional compilation will be inverted, while an ENDIF will terminate the conditional assembly block. For example: IF ABC GOTO aardvark ELSIF DEF GOTO denver ELSE GOTO grapes ENDIF In this example, if ABC is non-zero, the first GOTO instruction will be assembled but not the second or third. If ABC is zero and DEF is non-zero, the second GOTO instruction will be assembled but the first and third will not. If both ABC and DEF are zero, the third GOTO instruction will be assembled. Note in the above example, only one GOTO instruction will appear in the output; which one will be determined by the values assigned to ABC and DEF. Conditional assembly blocks may be nested. 4.3.9.12 MACRO AND ENDM These directives provide for the definition of assembly macros, optionally with arguments. See Section 4.3.9.5 “EQU” for simple association of a value with an identifier, or Section 3.15.1 “Preprocessor Directives” for the preprocessor’s #define macro directive, which can also work with arguments. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 132  2010 Microchip Technology Inc. The MACRO directive should be preceded by the macro name and optionally followed by a comma-separated list of formal arguments. When the macro is used, the macro name should be used in the same manner as a machine opcode, followed by a list of arguments to be substituted for the formal parameters. For example: ;macro: movlf ;args: arg1 - the literal value to load ; arg2 - the NAME of the source variable ;descr: Move a literal value into a nominated file register movlf MACRO arg1,arg2 MOVLW arg1 MOVWF arg2 mod 080h ENDM When used, this macro will expand to the 2 instructions in the body of the macro, with the formal parameters substituted by the arguments. Thus: movlf 2,tempvar expands to: MOVLW 2 MOVWF tempvar mod 080h The & character can be used to permit the concatenation of macro arguments with other text, but is removed in the actual expansion. For example: loadPort MACRO port, value MOVLW value MOVWF PORT&port ENDM will load PORTA if port is A when called, etc. A comment may be suppressed within the expansion of a macro (thus saving space in the macro storage) by opening the comment with a double semicolon, ;;. When invoking a macro, the argument list must be comma-separated. If it is desired to include a comma (or other delimiter such as a space) in an argument then angle brackets < and > may be used to quote If an argument is preceded by a percent sign, %, that argument will be evaluated as an expression and passed as a decimal number, rather than as a string. This is useful if evaluation of the argument inside the macro body would yield a different result. The nul operator may be used within a macro to test a macro argument, for example: IF nul arg3 ; argument was not supplied. ... ELSE ; argument was supplied ... ENDIF See Section 4.3.9.13 “LOCAL” for use of unique local labels within macros. By default, the assembly list file will show macro in an unexpanded format, i.e. as the macro was invoked. Expansion of the macro in the listing file can be shown by using the EXPAND assembler control, see Section 4.3.10.2 “EXPAND”. 4.3.9.13 LOCAL The LOCAL directive allows unique labels to be defined for each expansion of a given macro. Any symbols listed after the LOCAL directive will have a unique assembler generated symbol substituted for them when the macro is expanded. For example: down MACRO count Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 133 LOCAL more more: DECFSZ count GOTO more ENDM when expanded will include a unique assembler generated label in place of more. For example: down foobar expands to: ??0001 DECFSZ foobar GOTO ??0001 If invoked a second time, the label more would expand to ??0002 and multiply defined symbol errors will be averted. 4.3.9.14 ALIGN The ALIGN directive aligns whatever is following, data storage or code etc., to the specified offset boundary within the current psect. The boundary is specified as a number of bytes following the directive. For example, to align output to a 2 byte (even) address within a psect, the following could be used. ALIGN 2 Note that what follows will only begin on an even absolute address if the psect begins on an even address, i.e. alignment is done within the current psect. See Section 4.3.9.3.10 “Reloc” for psect alignment. The ALIGN directive can also be used to ensure that a psect’s length is a multiple of a certain number. For example, if the above ALIGN directive was placed at the end of a psect, the psect would have a length that was always an even number of bytes long. 4.3.9.15 REPT The REPT directive temporarily defines an unnamed macro, then expands it a number of times as determined by its argument. For example: REPT 3 ADDWF fred,w ENDM will expand to: ADDWF fred,w ADDWF fred,w ADDWF fred,w See also Section 4.3.9.16 “IRP and IRPC”. 4.3.9.16 IRP AND IRPC The IRP and IRPC directives operate in a similar way to REPT, however instead of repeating the block a fixed number of times, it is repeated once for each member of an argument list. In the case of IRP, the list is a conventional macro argument list; in the case or IRPC, it is each character in one argument. For each repetition the argument is substituted for one formal parameter. For example: IRP number,4865h,6C6Ch,6F00h DW number HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 134  2010 Microchip Technology Inc. ENDM would expand to: DW 4865h DW 6C6Ch DW 6F00h Note that you can use local labels and angle brackets in the same manner as with conventional macros. The IRPC directive is similar, except it substitutes one character at a time from a string of non-space characters. For example: IRPC char,ABC DB ’char’ ENDM will expand to: DB ’A’ DB ’B’ DB ’C’ 4.3.9.17 BANKSEL This directive can be used to generate code to select the bank of the operand. The operand should be the symbol or address of an object that resides in the data memory. Depending on the target device, the generated code will either contain one or more bit instructions to set/clear bits in the appropriate register, or use a MOVLB instruction in the case of enhanced Mid-Range PIC devices. In case this directive expands to more than one instruction, it should not immediately follow a BTFSX instruction. For example: MOVLW 20 BANKSEL (_foobar) ; select bank for next file instruction MOVWF _foobar&07fh ; write data and mask address 4.3.9.18 PAGESEL This directive can be used to generate code to select the current page, i.e. the page which contains this directive. Depending on the target device, the generated code will either contain one or more bit instructions to set/clear bits in the appropriate register, or use a MOVLP instruction in the case of enhanced Mid-Range PIC devices. In case this directive expands to more than one instruction, it should not immediately follow a BTFSX instruction. For example: CALL _getInput PAGESEL ; select this page 4.3.9.19 PROCESSOR The output of the assembler may vary depending on the target device. The device name is typically set using the --CHIP option to the command-line driver PICC, see Section 2.7.20 “--CHIP: Define Processor”, or using the assembler’s --CHIP option, see Section 4.2.15 “--CHIP: Specify Device Name”, but can also be set with this directive, e.g. PROCESSOR 16F877 This directive will override any processor selected by a command-line option. Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 135 4.3.9.20 SIGNAT This directive is used to associate a 16-bit signature value with a label. At link time the linker checks that all signatures defined for a particular label are the same and produces an error if they are not. The SIGNAT directive is used by HI-TECH C to enforce link time checking of C function prototypes and calling conventions. Use the SIGNAT directive if you want to write assembly language routines which are called from C. For example: SIGNAT _fred,8192 will associate the signature value 8192 with the symbol _fred. If a different signature value for _fred is present in any object file, the linker will report an error. The easiest way to determine the correct signature value for a routine is to write a C routine with the same prototype as the assembly routine and check the signature value determined by the code generator. This will be shown in the assembly list file, see Section 2.7.17 “--ASMLIST: Generate Assembler List Files” and Section 4.4 “Assembly List Files”. 4.3.10 Assembler Controls Assembler controls may be included in the assembler source to control assembler operation. These keywords have no significance anywhere else in the program. The control is invoked by the directive OPT followed by the control name. Some keywords are followed by one or more arguments. For example: OPT EXPAND A list of keywords is given in Table 4-7, and each is described further below. Note 1: The default options are listed with an asterisk (*) TABLE 4-7: ASPIC ASSEMBLER CONTROLS Control Meaning Format COND* Include conditional code in the list- ing COND EXPAND Expand macros in the listing output EXPAND INCLUDE Textually include another source file INCLUDE < pathname > LIST* Define options for listing output LIST [< listopt >, ..., < listopt >] NOCOND Leave conditional code out of the listing NOCOND NOEXPAND* Disable macro expansion NOEXPAND NOLIST Disable listing output NOLIST NOXREF Disable generation of cross reference file NOXREF PAGE Start a new page in the listing output PAGE SPACE Add blank lines to listing SPACE 3 SUBTITLE Specify the subtitle of the program SUBTITLE “< subtitle >” TITLE Specify the title of the program TITLE “< title >” XREF Enable cross reference file generation XREF HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 136  2010 Microchip Technology Inc. 4.3.10.1 COND Any conditional code will be included in the listing output. See also the NOCOND control in Section 4.3.10.5 “NOCOND”. 4.3.10.2 EXPAND When EXPAND is in effect, the code generated by macro expansions will appear in the listing output. See also the NOEXPAND control in Section 4.3.10.6 “NOEXPAND”. 4.3.10.3 INCLUDE This control causes the file specified by pathname to be textually included at that point in the assembly file. The INCLUDE control must be the last control keyword on the line, for example: OPT INCLUDE "options.h" The driver does not pass any search paths to the assembler, so if the include file is not located in the working directory, the pathname must specify the exact location. See also the driver option -P in Section 2.7.11 “-P: Preprocess Assembly Files” which forces the C preprocessor to preprocess assembly file, thus allowing use of preprocessor directives, such as #include (see Section 3.15.1 “Preprocessor Direc- tives”). 4.3.10.4 LIST If the listing was previously turned off using the NOLIST control, the LIST control on its own will turn the listing on. Alternatively, the LIST control may includes options to control the assembly and the listing. The options are listed in Table 4-8. See also the NOLIST control in Section 4.3.10.7 “NOLIST”. 4.3.10.5 NOCOND Using this control will prevent conditional code from being included in the assembly list file output. See also the COND control in Section 4.3.10.1 “COND”. 4.3.10.6 NOEXPAND The NOEXPAND control disables macro expansion in the assembly list file. The macro call will be listed instead. See also the EXPAND control in Section 4.3.10.2 “EXPAND”. Assembly macro are discussed in Section 4.3.9.12 “MACRO and ENDM”. 4.3.10.7 NOLIST This control turns the listing output off from this point onward. See also the LIST control in Section 4.3.10.4 “LIST”. TABLE 4-8: LIST CONTROL OPTIONS List Option Default Description c= nnn 80 Set the page (i.e. column) width. n= nnn 59 Set the page length. t= ON|OFF OFF Truncate listing output lines. The default wraps lines. p=< processor > n/a Set the processor type. r=< radix > HEX Set the default radix to HEX, dec or oct. x= ON|OFF OFF Turn macro expansion on or off. Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 137 4.3.10.8 NOXREF The NOXREF control will disable generation of the raw cross reference file. See also the XREF control in Section 4.3.10.13 “XREF”. 4.3.10.9 PAGE The PAGE control causes a new page to be started in the listing output. A Control-L (form feed) character will also cause a new page when encountered in the source. 4.3.10.10 SPACE The SPACE control will place a number of blank lines in the listing output as specified by its parameter. 4.3.10.11 SUBTITLE The SUBTITLE control defines a subtitle to appear at the top of every listing page, but under the title. The string should be enclosed in single or double quotes. See also the TITLE control in Section 4.3.10.12 “TITLE”. 4.3.10.12 TITLE This control keyword defines a title to appear at the top of every listing page. The string should be enclosed in single or double quotes. See also the SUBTITLE control in Section 4.3.10.11 “SUBTITLE”. 4.3.10.13 XREF The XREF control is equivalent to the driver command line option --CR (see Section 2.7.23 “--CR: Generate Cross Reference Listing”). It causes the assembler to produce a raw cross reference file. The utility CREF should be used to actually generate the formatted cross-reference listing. 4.4 ASSEMBLY LIST FILES The assembler will produce an assembly list file if instructed. The PICC driver option --ASMLIST is typically used to request generation of such a file, see Section 2.7.17 “--ASMLIST: Generate Assembler List Files”. The assembly list file shows the assembly output produced by the compiler for both C and assembly source code. If the assembler optimizers are enabled, the assembly output may be different to assembly source code and so is still useful for assembly programming. The list file is in a human readable form and cannot take any further part in the compilation sequence. It differs from an assembly output file in that it contains address and op-code data. In addition, the assembler optimizer simplifies some expressions and removes some assembler directives from the listing file for clarity, although these directives are included in the true assembly output files. If you are using the assembly list file to look at the code produced by the compiler, you may wish to turn off the assembler optimizer so that all the compiler-generated directives are shown in this file. Re-enable the optimizer when continuing development. Section 2.7.42 “--OPT: Invoke Compiler Optimizations” gives more information on controlling the optimizers. Provided the link stage has successfully concluded, the listing file will be updated by the linker so that it contains absolute addresses and symbol values. Thus you may use the assembler list file to determine the position of, and exact op codes of, instructions. There is one assembly list file produce by the assembler for each assembly file passed to it, and so there will be one file produced for all the C source code in a project, including p-code based library code. This file will also contains some of the C initialization HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 138  2010 Microchip Technology Inc. that forms part of the runtime startup code. There will also be one file produced for each assembly source file. There is typically at least one assembly file in each project, that containing some of the runtime startup file, typically called startup.as. 4.4.1 General Format The format of the main listing has the form as shown in Section Figure 4-1: “General form of assembly listing file”. The line numbers purely relate to the assembly list file and are not associated with the lines numbers in the C or assembly source files. Any assembly that begins with a semicolon indicates it is a comment added by the code generator. Such comments contain either the original source code which corresponds to the generated assembly, or is a comment inserted by the code generator to explain some action taken. Before the output for each function there is detailed information regarding that function summarized by the code generator. This information relates to register usage, local variable information, functions called and the calling function. FIGURE 4-1: GENERAL FORM OF ASSEMBLY LISTING FILE 4.4.2 Pointer Reference Graph Other important information contained in the assembly list file is the pointer reference graph (look for pointer list with targets: in the list file). This is a list of each and every pointer contained in the program and each target the pointer can reference through the program. The size and type of each target is indicated as well as the size and type of the pointer variable itself. For example, the following shows a pointer called task_tmr in the C code, and which is local to the function timer_intr(). It is a pointer to an unsigned int and it is one byte wide. There is only one target to this pointer and it is the member timer_count in the structure called task. This target variable resides in the BANK0 class and is two bytes wide. timer_intr@task_tmr PTR unsigned int size(1); Largest target is 2 -> task.timer_count(BANK0[2]), The pointer reference graph shows both pointers to data objects and pointers to func- tions. 768 ;sp2_inpADC.c: 119: void ADC_start(unsigned char chan) 769 ;sp2_inpADC.c: 120: { 770 0243 _ADC_start: 771 ; Regs used in _ADC_start: [reg0,reg3] 772 0243 00A3 instruction operands 773 ;sp2_inpADC.c: 121: chan &= 0x07; 774 0244 3007 instruction operands 775 0245 05A3 instruction operands 776 ;sp2_inpADC.c: 128: } 777 0252 0008 instruction 778 ; ========= function _ADC_start ends ======== 1 2 3 4 5 ======== line number address op code source comment assembly Macro Assembler  2010 Microchip Technology Inc. DS51865B-page 139 4.4.3 Call Graph The other important information block in the assembly list file is the call graph (look for Call graph: in the list file). This is produced for target devices that use a compiled stack to facilitate local variables, such as function parameters and auto variables. See Section 3.5.4 “Absolute Variables” for more detailed information on compiled stack operation. The call graph in the list file shows the information collated and interpreted by the code generator, which is primarily used to allow overlapping of functions’ APBs. The following information can be obtained from studying the call graph. • The functions in the program that are “root” nodes marking the top of a call tree, and which are called spontaneously • The functions that the linker deemed were called, or may have been called, during program execution • The program’s hierarchy of function calls • The size of the auto and parameter areas within each function’s APB • The offset of each function’s APB within the compiled stack • The estimated call tree depth. These features are discussed below. A typical call graph may look that shown inFigure 4-2. FIGURE 4-2: CALL GRAPH FORM The graph starts with the function main(). Note that the function name will always be shown in the assembly form, thus the function main() appears as the symbol _main. main() is always a root of a call tree. Interrupt functions will form separate trees. All the functions that main() calls, or may call, are shown below. These have been grouped in the orange box in the figure. A function’s inclusion into the call graph does not imply the function was actually called, but there is a possibility that the function was called. For example, code such as: int test(int a) { if(a) foo(); else bar(); } will list foo() and bar() under test(), as either may be called. If a is always true, then the function bar() will never be called even though it appears in the call graph. Call graph: Base Space Used Autos Args Refs Density _main 10 0 24 0.00 4 COMMO 6 16 BANK0 4 _rv _rvx _rvy _rvx 0 2 9 0.00 8 BANK0 2 _rv2 _rvy 0 2 3 0.00 0 BANK0 2 _rv 8 4 12 0.00 0 COMMO 4 8 BANK0 8 _rv2 _rv2 4 4 6 0.00 0 BANK0 8 Estimated maximum call depth 2 _main 10 0 24 0.00 4 COMMO 6 16 BANK0 4 _rv _rvx _rvy HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 140  2010 Microchip Technology Inc. In addition to these functions there is information relating to the memory allocated in the compiled stack for main(). This memory will be used for auto, temporary and parameter variables defined in main(). The only difference between an auto and temporary variable is that auto variables are defined by the programmer, and temporaries are defined by the compiler, but both behave in the same way. In the orange box for main() you can see that it defines 10 auto and temporary variable. It defines no parameters (main() never has parameters). There is a total of 24 references in the assembly code to local objects in main(). Rather than the compiled stack being one memory allocation in one memory space, it can have components placed in multiple memory spaces to utilize all available memory of the target device. This break down is shown under the memory summary line for each function. In this example, it shows that some of the local objects for main() are placed in the common memory, but others are placed in bank 0 data RAM. The Used column indicates how many bytes of memory are used by each section of the compiled stack and the Space column indicates in which space that has been placed. The Base value indicates the offset that block has in the respective section of the compiled stack. For example, the figure tells us main()has 6 bytes of memory allocated at an offset of 4 in the compiled stack section that lives in common memory. It also has 4 bytes of memory allocated in bank 0 memory at an offset of 16 in the bank 0 compiled stack component. Below the information for main() (outside the orange box) you will see the same information repeated for the functions that main() called, viz. rv(), rvx() and rvy(). Indentation is used to indicate the maximum depth that function reaches in the call graph. The arrows in the figure highlight this indentation. After each tree in the call graph, there is an indication of the maximum call (stack) depth that might be realized by that tree. This may be used as a guide to the stack usage of the program. No definitive value can be given for the program’s total stack usage for several reasons: • Certain parts of the call tree may never be reached, reducing that tree’s stack usage. • The contribution of interrupt (or other) trees to the main() tree cannot be determined as the point in main ’s call tree at which the interrupt (or other function invocation) will occur cannot be known; • The assembler optimizer may have replaced function calls with jumps to functions, reducing that tree’s stack usage. • The assembler’s procedural abstraction optimizations may have added in calls to abstracted routines. (Checks are made to ensure this does not exceed the maximum stack depth.) The code generator also produces a warning if the maximum stack depth appears to have been exceeded. For the above reasons, this warning, too, is intended to be a only a guide to potential stack problems. HI-TECH C® FOR PIC10/12/16 USER’S GUIDE  2010 Microchip Technology Inc. DS51865B-page 141 Chapter 5. Linker 5.1 INTRODUCTION This chapter describes the theory behind, and the usage of, the linker. The application name of the linker is HLINK. In most instances it will not be necessary to invoke the linker directly, as the compiler driver, PICC, will automatically execute the linker with all necessary arguments. Using the linker directly is not simple, and should be attempted only by those with a sound knowledge of the compiler and linking in general. The compiler often makes assumptions about the way in which the program will be linked. If the psects are not linked correctly, code failure may result. If it is absolutely necessary to use the linker directly, the best way to start is to copy the linker arguments constructed by the compiler driver, and modify them as appropriate. This will ensure that the necessary startup module and arguments are present. 5.2 OPERATION A command to the linker takes the following form: hlink [options] files The options are zero or more linker options, each of which modifies the behavior of the linker in some way. The files is one or more object files, and zero or more object code library names (.lib extension). P-code libraries (.lpp extension) are always passed to the code generator application and cannot be passed to the linker. The options recognized by the linker are listed in Table 5-1 and discussed in the following paragraphs. TABLE 5-1: LINKER COMMAND-LINE OPTIONS Option Effect -8 Use 8086 style segment:offset address form -Aclass=low-high ,... Specify address ranges for a class -Cx Call graph options -Cpsect=class Specify a class name for a global psect -Cbaseaddr Produce binary output file based at baseaddr -Dclass=delta Specify a class delta value -Dsymfile Produce old-style symbol file -Eerrfile Write error messages to errfile -F Produce .obj file with only symbol records -G spec Specify calculation for segment selectors -H symfile Generate symbol file -H+ symfile Generate enhanced symbol file -I Ignore undefined symbols -J num Set maximum number of errors before aborting -K Prevent overlaying function parameter and auto areas -L Preserve relocation items in .obj file -LM Preserve segment relocation items in .obj file HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 142  2010 Microchip Technology Inc. If the standard input is a file then this file is assumed to contain the command-line argument. Lines may be broken by leaving a backslash \ at the end of the preceding line. In this fashion, HLINK commands of almost unlimited length may be issued. For example a link command file called x.lnk and containing the following text: -Z -OX.OBJ -MX.MAP \ -Ptext=0,data=0/,bss,nvram=bss/. \ X.OBJ Y.OBJ Z.OBJ may be passed to the linker by one of the following: hlink @x.lnk hlink < x.lnk Several linker options require memory addresses or sizes to be specified. The syntax for all these is similar. By default, the number will be interpreted as a decimal value. To force interpretation as a HEX number, a trailing H, or h, should be added, e.g. 765FH will be treated as a HEX number. 5.2.1 -Aclass =low-high,... Normally psects are linked according to the information given to a -P option (see Section 5.2.18 “-Pspec”) but sometimes it is desirable to have a class of psects linked into more than one non-contiguous address range. This option allows a number of address ranges to be specified as a class. For example: -ACODE=1020h-7FFEh,8000h-BFFEh specifies that psects in the class CODE are to be linked into the given address ranges, unless they are specifically linked otherwise. -N Sort symbol table in map file by address order -Nc Sort symbol table in map file by class address order -Ns Sort symbol table in map file by space address order -Mmapfile Generate a link map in the named file -Ooutfile Specify name of output file -Pspec Specify psect addresses and ordering -Qprocessor Specify the processor type (for cosmetic reasons only) -S Inhibit listing of symbols in symbol file -Sclass=limit[,bound] Specify address limit, and start boundary for a class of psects -Usymbol Pre-enter symbol in table as undefined -Vavmap Use file avmap to generate an Avocet format symbol file -Wwarnlev Set warning level (-9 to 9) -Wwidth Set map file width (>=10) -X Remove any local symbols from the symbol file -Z Remove trivial local symbols from the symbol file --DISL=list Specify disabled messages --EDF=path Specify message file location --EMAX=number Specify maximum number of errors --NORLF Do not relocate list file --VER Print version number and stop TABLE 5-1: LINKER COMMAND-LINE OPTIONS (CONTINUED) Option Effect Linker  2010 Microchip Technology Inc. DS51865B-page 143 Where there are a number of identical, contiguous address ranges, they may be specified with a repeat count following an x character. For example: -ACODE=0-0FFFFhx16 specifies that there are 16 contiguous ranges, each 64k bytes in size, starting from address zero. Even though the ranges are contiguous, no psect will straddle a 64k boundary, thus this may result in different psect placement to the case where the option -ACODE=0-0FFFFFh had been specified, which does not include boundaries on 64k multiples. The -A option does not specify the memory space associated with the address. Once a psect is allocated to a class, the space value of the psect is then assigned to the class, see Section 4.3.9.3.12 “Space”. 5.2.2 -Cx This option is now obsolete. -Cpsect=class This option will allow a psect to be associated with a specific class. Normally this is not required on the command line since psect classes are specified in object files. See Section 4.3.9.3.3 “Class”. 5.2.3 -Dclass=delta This option allows the delta value for psects that are members of the specified class to be defined. The delta value should be a number and represents the number of bytes per addressable unit of objects within the psects. Most psects do not need this option as they are defined with a delta value. See Section 4.3.9.3.4 “Delta”. 5.2.4 -Dsymfile Use this option to produce an old-style symbol file. An old-style symbol file is an ASCII file, where each line has the link address of the symbol followed by the symbol name. 5.2.5 -Eerrfile Error messages from the linker are written to the standard error stream. Under DOS there is no convenient way to redirect this to a file (the compiler drivers will redirect standard error if standard output is redirected). This option will make the linker write all error messages to the specified file instead of the screen, which is the default standard error destination. 5.2.6 -F Normally the linker will produce an object file that contains both program code and data bytes, and symbol information. Sometimes it is desired to produce a symbol-only object file that can be used again in a subsequent linker run to supply symbol values. The -F option will suppress data and code bytes from the output file, leaving only the symbol records. This option can be used when part of one project (i.e. a separate build) is to be shared with other, as might be the case with a bootloader and application. The files for one project are compiled using this linker option to produce a symbol-only object file; this is then linked with the files for the other project. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 144  2010 Microchip Technology Inc. 5.2.7 -Gspec When linking programs using segmented, or bank-switched psects, there are two ways the linker can assign segment addresses, or selectors, to each segment. A segment is defined as a contiguous group of psects where each psect in sequence has both its link and load address concatenated with the previous psect in the group. The segment address or selector for the segment is the value derived when a segment type relocation is processed by the linker. By default the segment selector will be generated by dividing the base load address of the segment by the relocation quantum of the segment, which is based on the reloc= flag value given to psects at the assembler level, see Section 4.3.9.3.10 “Reloc”. The -G option allows an alternate method for calculating the segment selector. The argument to -G is a string similar to: A /10h-4h where A represents the load address of the segment and / represents division. This means “Take the load address of the psect, divide by 10 HEX, then subtract 4". This form can be modified by substituting N for A, * for / (to represent multiplication), and adding rather than subtracting a constant. The token N is replaced by the ordinal number of the segment, which is allocated by the linker. For example: N*8+4 means "take the segment number, multiply by 8 then add 4". The result is the segment selector. This particular example would allocate segment selectors in the sequence 4, 12, 20, ... for the number of segments defined. The selector of each psect is shown in the map file. See Section 5.4.2.2 “Psect Information listed by Module”. 5.2.8 -Hsymfile This option will instruct the linker to generate a symbol file. The optional argument symfile specifies the name of the file to receive the data. The default file name is l.sym. 5.2.9 -H+symfile This option will instruct the linker to generate an enhanced symbol file, which provides, in addition to the standard symbol file, class names associated with each symbol and a segments section which lists each class name and the range of memory it occupies. This format is recommended if the code is to be run in conjunction with a debugger. The optional argument symfile specifies a file to receive the symbol file. The default file name is l.sym. 5.2.10 -I Usually failure to resolve a reference to an undefined symbol is a fatal error. Use of this option will cause undefined symbols to be treated as warnings instead. 5.2.11 -Jerrcount The linker will stop processing object files after a certain number of errors (other than warnings). The default number is 10, but the -J option allows this to be altered. 5.2.12 -K For compilers that use a compiled stack, the linker will try and overlay function auto and parameter blocks to reduce the total amount of RAM required. For debugging purposes, this feature can be disabled with this option, however doing so will increase the data memory requirements. Linker  2010 Microchip Technology Inc. DS51865B-page 145 5.2.13 -L When the linker produces an output file it does not usually preserve any relocation information, since the file is now absolute. In some circumstances a further "relocation" of the program will be done at load time. The -L option will generate in the output file one null relocation record for each relocation record in the input. 5.2.14 -LM Similar to the above option, this preserves relocation records in the output file, but only segment relocations. 5.2.15 -Mmapfile This option causes the linker to generate a link map in the named file, or on the standard output if the file name is omitted. The format of the map file is illustrated in Section Section 5.4 “Map Files”. 5.2.16 -N, -Ns and-Nc By default the symbol table in the map file will be sorted by name. The -N option will cause it to be sorted numerically, based on the value of the symbol. The -Ns and -Nc options work similarly except that the symbols are grouped by either their space value, or class. 5.2.17 -Ooutfile This option allows specification of an output file name for the linker. The default output file name is l.obj. Use of this option will override the default. 5.2.18 -Pspec Psects are linked together and assigned addresses based on information supplied to the linker via -P options. The argument to the -P option consists basically of comma -separated sequences thus: -Ppsect =lnkaddr+min/ldaddr+min,psect=lnkaddr/ldaddr,... There are several variations, but essentially each psect is listed with its desired link and load addresses, and a minimum value. All values may be omitted, in which case a default will apply, depending on previous values. If present, the minimum value, min, is preceded by a + sign. It sets a minimum value for the link or load address. The address will be calculated as described below, but if it is less than the minimum then it will be set equal to the minimum. The link and load addresses are either numbers, or the names of other psects, classes, or special tokens. If the link address is a negative number, the psect is linked in reverse order with the top of the psect appearing at the specified address minus one. Psects following a negative address will be placed before the first psect in memory. If a psect’s link address is omitted, it will be derived from the top of the previous psect. For example, in the following: -Ptext=100h,data,bss the text psect is linked at 100h (its load address defaults to the same). The data psect will be linked (and loaded) at an address which is 100 HEX plus the length of the text psect, rounded up as necessary if the data psect has a reloc value associated with it (see Section 4.3.9.3.10 “Reloc”). Similarly, the bss psect will concatenate with the data psect. Again: -Ptext=-100h,data,bss HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 146  2010 Microchip Technology Inc. will link in ascending order bss, data then text with the top of the text psect appearing at address 0ffh. If the load address is omitted entirely, it defaults to the same as the link address. If the slash / character is supplied, but no address is supplied after it, the load address will concatenate with the previous psect. For example: -Ptext=0,data=0/,bss will cause both text and data to have a link address of zero; text will have a load address of zero, and data will have a load address starting after the end of text. The bss psect will concatenate with data in terms of both link and load addresses. The load address may be replaced with a dot character, ".". This tells the linker to set the load address of this psect to the same as its link address. The link or load address may also be the name of another (previously linked) psect. This will explicitly concatenate the current psect with the previously specified psect, e.g. -Ptext=0,data=8000h/,bss/. -Pnvram=bss,heap This example shows text at zero, data linked at 8000h but loaded after text; bss is linked and loaded at 8000h plus the size of data, and nvram and heap are concatenated with bss. Note here the use of two -P options. Multiple -P options are processed in order. If -A options (see Section 5.2.1 “-Aclass =low-high,...”) have been used to specify address ranges for a class then this class name may be used in place of a link or load address, and space will be found in one of the address ranges. For example: -ACODE=8000h-BFFEh,E000h-FFFEh -Pdata=C000h/CODE This will link data at C000h, but find space to load it in the address ranges associated with the CODE class. If no sufficiently large space is available in this class, an error will result. Note that in this case the data psect will still be assembled into one contiguous block, whereas other psects in the class CODE will be distributed into the address ranges wherever they will fit. This means that if there are two or more psects in class CODE, they may be intermixed in the address ranges. Any psects allocated by a -P option will have their load address range subtracted from the address ranges associate with classes in the same memory space. This allows a range to be specified with the -A option without knowing in advance how much of the lower part of the range, for example, will be required for other psects. The final link and load address of psects are shown in the map file. See Section 5.4.2.2 “Psect Information listed by Module”. 5.2.19 -Qprocessor This option allows a processor type to be specified. This is purely for information placed in the map file. The argument to this option is a string describing the processor. There are no behavioral changes attributable to the processor type. 5.2.20 -S This option prevents symbol information relating from being included in the symbol file produced by the linker. Segment information is still included. 5.2.21 -Sclass =limit[,bound] A class of psects may have an upper address limit associated with it. The following example places a limit on the maximum address of the CODE class of psects to one less than 400h. -SCODE=400h Linker  2010 Microchip Technology Inc. DS51865B-page 147 Note that to set an upper limit to a psect, this must be set in assembler code using the psect limit flag, see Section 4.3.9.3.6 “Limit”). If the bound (boundary) argument is used, the class of psects will start on a multiple of the bound address. This example below places the FARCODE class of psects at a multiple of 1000h, but with an upper address limit of 6000h. -SFARCODE=6000h,1000h 5.2.22 -Usymbol This option will enter the specified symbol into the linker’s symbol table as an undefined symbol. This is useful for linking entirely from libraries, or for linking a module from a library where the ordering has been arranged so that by default a later module will be linked. 5.2.23 -Vavmap To produce an Avocet format symbol file, the linker needs to be given a map file to allow it to map psect names to Avocet memory identifiers. The avmap file will normally be supplied with the compiler, or created automatically by the compiler driver as required. 5.2.24 -Wnum The -W option can be used to set the warning level, in the range -9 to 9, or the width of the map file, for values of num >= 10. -W9 will suppress all warning messages. -W0 is the default. Setting the warning level to -9 (-W-9) will give the most comprehensive warning messages. 5.2.25 -X Local symbols can be suppressed from a symbol file with this option. Global symbols will always appear in the symbol file. 5.2.26 -Z Some local symbols are compiler generated and not of interest in debugging. This option will suppress from the symbol file all local symbols that have the form of a single alphabetic character, followed by a digit string. The set of letters that can start a trivial symbol is currently “klfLSu “. The -Z option will strip any local symbols starting with one of these letters, and followed by a digit string. 5.2.27 --DISL=message numbers Disable Messages This option is mainly used by the command-line driver, PICC, to disable particular message numbers. It takes a comma-separate list of message numbers that will be disabled during compilation. This option is applied if compiling using PICC, the command-line driver and the --MSGDISABLE driver option, see Section 2.7.37 “--MSGDISABLE: Disable Warning Messages”. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 5.2.28 --EDF=message file: Set Message File Path This option is mainly used by the command-line driver, PICC, to specify the path of the message description file. The default file is located in the dat directory in the compiler’s installation directory. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 148  2010 Microchip Technology Inc. 5.2.29 --EMAX=number: Specify Maximum Number of Errors This option is mainly used by the command-line driver, PICC, to specify the maximum number of errors that can be encountered before the assembler terminates. The default number is 10 errors. This option is applied if compiling using PICC, the command-line driver and the --ERRORS driver option, see Section 2.7.28 “--ERRORS: Maximum Number of Errors”. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 5.2.30 --NORLF: Do Not Relocate List File Use of this option prevents the linker applying fixups to the assembly list file produced by the assembler. This option is normally using by the command line driver, PICC, when performing pre-link stages, but is omitted when performing the final link step so that the list file shows the final absolute addresses. If you are attempting to resolve fixup errors, this option should be disabled so as to fixup the assembly list file and allow absolute addresses to be calculated for this file. If the compiler driver detects the presence of a preprocessor macro __DEBUG which is equated to 1, then this option will be disabled when building. This macro is set when choosing a Debug build in MPLAB IDE, so always have this selected if you encounter such errors. 5.2.31 --VER: Print Version Number This option printed information relating to the version and build of the linker. The linker will terminate after processing this option, even if other options and files are present on the command line. 5.3 RELOCATION AND PSECTS This section looks at the input files that the linker has to work with. The linker can read both relocatable object files and object-file libraries (.lib extension). The library files are a collection of object files packaged into a single unit, so essentially we only need consider the format of object files. Each object file consists of a number of records. Each record has a type that indicates what sort of information it holds. Some record types hold general information about the target device and its configuration, other records types may hold data, and others, program debugging information, for example. A lot of the information in object files relates to psects. Psects are an assembly domain construct and are essentially a block of something, either instructions or data. Everything that contributes to the program is located in a psect. See Section 4.3.8 “Program Sections”. There is a particular record type that is used to hold the data in psects. The bulk of each object file consists of psect records containing the executable code and variables etc. We are now in a position to look at the fundamental tasks the linker performs, which are: • combining all the relocatable object files into one • relocation of psects contained in the object files into memory • fixup of symbolic references in the psects Linker  2010 Microchip Technology Inc. DS51865B-page 149 There is typically at least two object files that are passed to the linker. One will be produced from all the C code in the project, including C library code. There is only one of these files since the code generator compiles and combines all the C code of the program and produces just the one assembly output. The other file passed to the linker will be the object code produced from the runtime startup code, see Section 2.4.2 “Runtime Startup Code”. If there are assembly source files in the project, then there will also be one object file produced for each source file and these will be passed to the linker. Existing object files, or object file libraries can also be specified in a project, and if present, these will also be passed to the linker. The output of the linker is also an object file, but there is only ever one file produced. The file is absolute since relocation will have been performed by the linker. The output file will consist of the information from all input object files merged together. Relocation consists of placing the psect data into the memory of the target device. The target device memory specification is passed to the linker by the way of linker options. These options are generated by the command-line driver, PICC. There are no linker scripts or means of specifying options in any source file. The default linker options rarely need adjusting, but can be changed, if required and with caution, using the driver option -L-, see Section 2.7.7 “-L-: Adjust Linker Options Directly”. Once psects are placed at actual memory locations, symbolic references made in the psects data can be replaced with absolute values. This is a process called fixup. For each psect record in the object file, there is a corresponding relocation record that indicates which bytes (or bits) in the psect record need to be adjusted once relocation is complete. The relocation records also specify how the values are to be determined. A linker fixup overflow error can occur if the value determined by the linker is too large to fit in the “hole” reserved for the value in the psect. See Section “(477) fixup overflow in expression (location 0x* (0x*+*), size *, value 0x*) (Linker)” for information on finding the cause of these errors. 5.4 MAP FILES The map file contains information relating to the relocation of psects and the addresses assigned to symbols within those psects. 5.4.1 Generation If compilation is being performed via an IDE such as HI-TIDE or MPLAB IDE, a map file is generated by default without you having to adjust the compiler options. If you are using the driver from the command line then you’ll need to use the -M option to request that the map file be produced, see Section 5.2.15 “-Mmapfile”. Map files use the extension .map. Map files are produced by the linker. If the compilation process is stopped before the linker is executed, then no map file is produced. The linker will still produce a map file even if it encounters errors, which will allow you to use this file to track down the cause of the errors. However, if the linker ultimately reports too many errors then it did not run to completion, and the map file will be either not created or not complete. You can use the --ERRORS option (see Section 2.7.28 “--ERRORS: Maximum Number of Errors”) on the command line to increase the number of errors before the linker exits. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 150  2010 Microchip Technology Inc. 5.4.2 Contents The sections in the map file, in order of appearance, are as follows. • The compiler name and version number • A copy of the command line used to invoke the linker • The version number of the object code in the first file linked • The machine type • The call graph information • A psect summary sorted by the psect’s parent object file • A psect summary sorted by the psect’s CLASS • A segment summary • Unused address ranges summary • The symbol table Portions of an example map file, along with explanatory text, are shown in the following sections. 5.4.2.1 GENERAL INFORMATION At the top of the map file is general information relating to the execution of the linker. When analyzing a program, always confirm the compiler version number shown in the map file if you have more than one compiler version installed to ensure the desired compiler is being executed. The device selected with the --CHIP option (Section 2.7.20 “--CHIP: Define Processor”) or that select in your IDE, should appear after the Machine type entry. The object code version relates to the file format used by relocatable object files produced by the assembler. Unless either the assembler or linker have been updated independently, this should not be of concern. A typical map file may begin something like the following. This example has been cut down for clarity. --edf=C:\Program Files\HI-TECH Software\PICC\PRO\9.65pl1\dat\en_msgs.txt \ -cs -h+test.sym -z -Q16F946 -ol.obj -Mtest.map -E1 -ACODE=00h-07FFhx4 \ -ACONST=00h-0FFhx32 -AENTRY=00h-0FFhx32 -ASTRING=00h-0FFhx32 \ -ARAM=020h-06Fh,0A0h-0EFh,0120h-016Fh,01A0h-01EFh \ -AABS1=020h-07Fh,0A0h-0EFh,0120h-016Fh,01A0h-01EFh -ABANK0=020h-07Fh \ -ABANK1=0A0h-0EFh -ABANK2=0120h-016Fh -ABANK3=01A0h-01EFh \ -ACOMMON=070h-07Fh \ -preset_vec=00h,intentry,intcode,intret,init,init23,end_init,...\ -pstrings=CODE -ppowerup=CODE -ptemp=-COMMON -pcommon=-COMMON \ -prbss_0=BANK0,rbit_0=BANK0,rdata_0=BANK0,idata_0=CODE -pnvram=BANK0 \ -prbss_1=BANK1,rbit_1=BANK1,rdata_1=BANK1,idata_1=CODE \ -pnvram_1=BANK1,nvbit_1=BANK1 \ -ACONFIG=02007h-02007h -pconfig=CONFIG -DCONFIG=2 -AIDLOC=02000h-02003h \ -pidloc=IDLOC -DIDLOC=2 -AEEDATA=00h-0FFh/02100h -peeprom_data=EEDATA \ -DEEDATA=2 -pfloat_text0=CODE,float_text1=CODE,float_text2=CODE \ -pfloat_text3=CODE,float_text4=CODE -DCODE=2 startup.obj test.obj Object code version is 3.10 Machine type is 16F946 The Linker command line shows all the command-line options and files that were passed to the linker for the last build. Remember, these are linker options and not command-line driver options. Linker  2010 Microchip Technology Inc. DS51865B-page 151 The linker options are necessarily complex. Fortunately, they rarely need adjusting from their default settings. They are formed by the command-line driver, PICC, based on the selected target device and the specified driver options. You can often confirm that driver options were valid by looking at the linker options in the map file. For example, if you ask the driver to reserve an area of memory, you should see a change in the linker options used. If the default linker options must be changed, this can be done indirectly through the driver using the driver -L- option, see Section 2.7.7 “-L-: Adjust Linker Options Directly”. If you use this option, always confirm the change appears correctly in the map file. 5.4.2.2 PSECT INFORMATION LISTED BY MODULE The next section in the map file lists those modules that made a contribution to the output, and information regarding the psects these modules defined. This section is heralded by the line that contains the headings: Name Link Load Length Selector Space Scale Under this on the far left is a list of object files. These object files include both files generated from source modules and those that were extracted from object library files (.lib extension). In the latter case, the name of the library file is printed before the object file list. Note that since the code generator combines all C source files (and p-code libraries), there will only be one object file representing the entire C part of the program. The object file corresponding to the runtime startup code is normally present in this list. The information in this section of the map file can be used to confirm that a module is making a contribution to the output file and to determine the exact psects that each module defines. Shown are all the psects (under the Name column) that were linked into the program from each object file, and information about that psect. The linker deals with two kinds of addresses: link and load. Generally speaking the link address of a psect is the address by which it will be accessed at run time. The load address, which is often the same as the link address, is the address at which the psect will start within the output file (HEX or binary file etc.). If a psect is used to hold bits, the load address is irrelevant and is instead used to hold the link address (in bit units) converted into a byte address. The Length of the psect is shown in the units used by that psect. The Selector is less commonly used and is of no concern when compiling for PIC devices. The Space field is important as it indicates the memory space in which the psect was placed. For Harvard architecture machines, with separate memory spaces (such as the PIC10/12/16 devices), this field must be used in conjunction with the address to specify an exact storage location. A space of 0 indicates the program memory, and a space of 1 indicates the data memory. See Section 4.3.9.3.12 “Space”. The Scale of a psect indicates the number of address units per byte. This is left blank if the scale is 1 and will show 8 for psects that hold bit objects. The load address of psects that hold bits is used to display the link address converted into units of bytes, rather than the load address. See Section 4.3.9.3.2 “Bit”. For example, the following appears in a map file. Name Link Load Length Selector Space Scale ext.obj text 3A 3A 22 30 0 bss 4B 4B 10 4B 1 rbit 50 A 2 0 1 8 HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 152  2010 Microchip Technology Inc. This indicates that one of the files that the linker processed was called ext.obj. (This may have been derived from C code or a source file called ext.as.) This object file contained a text psect, as well as psects called bss and rbit. The psect text was linked at address 3A and bss at address 4B. At first glance, this seems to be a problem given that text is 22 words long, however note that they are in different memory areas, as indicated by the space flag (0 for text and 1 for bss), and so do not occupy the same memory. The psect rbit contains bit objects, and this can be confirmed by looking it the scale value, which is 8. Again, at first glance there seems there could be an issue with rbit linked over the top of bss. Their space flags are the same, but since rbit contains bit objects, its link address is in units of bits. Note that the load address field of rbit psect displays the link address converted to byte units, i.e. 50h/8 => Ah. Underneath the object file list there may be a label COMMON. This shows the contribution to the program from program-wide psects, in particular that used by the compiled stack. 5.4.2.3 PSECT INFORMATION LISTED BY CLASS The next section in the map file shows the same psect information but grouped by the psects’ class. This section is heralded by the line that contains the headings: TOTAL Name Link Load Length Under this are the class names followed by those psects which belong to this class, see Section 4.3.9.3.3 “Class”. These psects are the same as those listed by module in the above section; there is no new information contained in this section, just a different presentation. 5.4.2.4 SEGMENT LISTING The class listing in the map file is followed by a listing of segments. A segment is conceptual grouping of contiguous psects in the same memory space, and are used by the linker as an aid in psect placement. There is no segment assembler directive and segments cannot be controlled in any way. This section is heralded by the line that contains the headings: SEGMENTS Name Load Length Top Selector Space Class The name of a segment is derived from the psect in the contiguous group with the lowest link address. This can lead to confusion with the psect with the same name. Do not read psect information from this section of the map file. Typically this section of the map file can be ignored by the user. 5.4.2.5 UNUSED ADDRESS RANGES The last of the memory summaries show the memory is has not been allocated, and is hence unused. The linker is aware of any memory allocated by the code generator (for absolute variables), and so this free space is accurate. This section follows the heading: UNUSED ADDRESS RANGES and is followed by a list of classes and the memory still available in each class. If there is more than one memory range available in a class, each range is printed on a separate line. Any paging boundaries within a class are not displayed, but the column Largest block shows the largest contiguous free space which takes into account any paging in the memory range. If you are looking to see why psects cannot be placed into memory (e.g. cant-find-space type errors) then this important information to study. Linker  2010 Microchip Technology Inc. DS51865B-page 153 Note that the memory associated with a class can overlap that in others, thus the total free space is not simply the addition of all the unused ranges. 5.4.2.6 SYMBOL TABLE The final section in the map file list global symbols that the program defines. This section has a heading: Symbol Table and is followed by two columns in which the symbols are alphabetically listed. As always with the linker, any C derived symbol is shown with its assembler equivalent symbol name. See Section 3.13.3.1 “Equivalent Assembly Symbols”. The symbols listed in this table are: • Global assembly labels • Global EQU /SET assembler directive labels • Linker-defined symbols Assembly symbols are made global via the GLOBAL assembler directive, see Section 4.3.9.1 “GLOBAL” for more information. Linker-defined symbols act like EQU directives, however they are defined by the linker during the link process, and no definition for them will appear in any source or intermediate file. See Section 3.16.3 “Linker-Defined Symbols”. Each symbol is shown with the psect in which they are placed, and the value (usually an address) which the symbol has been assigned. There is no information encoded into a symbol to indicate whether it represents code or data, nor in which memory space it resides. If the psect of a symbol is shown as (abs), this implies that the symbol is not directly associated with a psect. Such is the case for absolute C variables, or any symbols that are defined using an EQU directive in assembly. Note that a symbol table is also shown in each assembler list file. (See Section 2.7.17 “--ASMLIST: Generate Assembler List Files” for information on generating these files.) These differ to that shown in the map file in that they list also list local symbols, and only show symbols defined in the corresponding module. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 154  2010 Microchip Technology Inc. NOTES: HI-TECH C® FOR PIC10/12/16 USER’S GUIDE  2010 Microchip Technology Inc. DS51865B-page 155 Chapter 6. Utilities 6.1 INTRODUCTION This chapters discusses some of the utility applications that are bundled with the compiler. Some of these applications may not be normally invoked when building, but can be manually executed to perform certain tasks. 6.2 LIBRARIAN The librarian program, LIBR, has the function of combining several files into a single file known as a library. The reasons you might want to use a library in a project are: • there will be fewer files to link • the file content will be accessed faster • libraries uses less disk space The librarian can build p-code libraries (.lpp extension) from p-code files (.p1 extension), or object code libraries (.lib extension) from object files (.obj extension). P-code libraries should be only created if all the library source code is written in C. Object code libraries should be used for assembly code that is to be built into a library. With both library types, only those modules required by a program will be extracted and included in the program output. 6.2.1 The Library Format The modules in a library are simply concatenated, but a directory of the modules and symbols in the library is maintained at the beginning of a library file. Since this directory is smaller than the sum of the modules, on the first pass the linker can perform faster searches just reading the directory, and not all the modules. On the second pass it need read only those modules which are required, seeking over the others. This all minimizes disk I/O when linking. It should be noted that the library format is not a general purpose archiving mechanism as is used by some other compiler systems. This has the advantage that the format may be optimized toward speeding up the linkage process. 6.2.2 Using the Librarian Library files can be built directly using the command-line driver, see Section 2.7.44 “--OUTPUT= type: Specify Output File Type”. In this case the driver will invoke LIBR with the appropriate options saving you from having to use the librarian directly. You may wish to perform this step manually, or you may need to look at the contents of library files, for example. This section shows how the librarian can be executed from the command-line. The librarian cannot be called from IDEs, such as MPLAB IDE. The librarian program is called LIBR, and the formats of commands to it are as follows: LIBR [options] k file.lpp [file1.p1 file2.p1...] LIBR [options] k file.lib [file1.obj file2.obj ...] HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 156  2010 Microchip Technology Inc. The options are zero or more librarian options which affect the output of the program. These are listed in Table 6-1. A key letter, k, denotes the command requested of the librarian (replacing, extracting or deleting modules, listing modules or symbols). These commands are listed in Table 6-2. The first file name listed after the key is the name of the library file to be used. The following files, if required, are the modules of the library required by the command specified. If you are building a p-code library, the modules listed must be p-code files. If you are building an object file library, the modules listed must be object files. When replacing or extracting modules, the names of the modules to be replaced or extracted must be specified. If no names are supplied, all the modules in the library will be replaced or extracted respectively. Adding a file to a library is performed by requesting the librarian to replace it in the library. Since it is not present, the module will be appended to the library. If the r key is used and the library does not exist, it will be created. When using the d key letter, the named modules will be deleted from the library. In this instance, it is an error not to give any module names. The m and s key letters will list the named modules and, in the case of the s key letter, the global symbols defined or referenced within. A D or U letter is used to indicate whether each symbol is defined in the module, or referenced but undefined. As with the r and x key letters, an empty list of modules means all the modules in the library. The o key takes a list of module names and re-orders the matching modules in the library file so they have the same order as that listed on the command line. Modules which are not listed are left in their existing order, and will appear after the re-ordered modules. TABLE 6-1: LIBRARIAN COMMAND-LINE OPTIONS Option Effect -P width Specify page width -W Suppress non-fatal errors TABLE 6-2: LIBRARIAN KEY LETTER COMMANDS Key Meaning r Replace modules d Delete modules x Extract modules m List modules s List modules with symbols o Re-order modules Utilities  2010 Microchip Technology Inc. DS51865B-page 157 6.2.2.1 EXAMPLES Here are some examples of usage of the librarian. The following command: LIBR s htpic--c.lpp ctime.p1 lists the global symbols in the modules ctime.p1, as shown here: ctime.p1 D _moninit D _localtime D _gmtime D _asctime D _ctime The D letter before each symbol indicates that these symbols are defined by the module. Using the command above without specifying the module name will list all the symbols defined (or undefined) in the library. The following command deletes the object modules a.obj, b.obj and c.obj from the library lcd.lib: LIBR d lcd.lib a.obj b.obj c.obj 6.2.3 Supplying Arguments Since it is often necessary to supply many object file arguments to LIBR, arguments will be read from standard input if no command-line arguments are given. If the standard input is attached to the console, LIBR will prompt for input. Multiple line input may be given by using a backslash as a continuation character on the end of a line. If standard input is redirected from a file, LIBR will take input from the file, without prompting. For example: libr libr> r file.lib 1.obj 2.obj 3.obj \ libr> 4.obj 5.obj 6.obj will perform much the same as if the object files had been typed on the command line. The libr> prompts were printed by LIBR itself, the remainder of the text was typed as input. libr prompt. A backslash at the end of the line will be interpreted to mean that more command lines follow. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 160  2010 Microchip Technology Inc. CREF takes the options listed in Section Table 6-4: “CREF command-line options”. Each option is described in more detail in the following sections. 6.4.1 -Fprefix It is often desired to exclude from the cross-reference listing any symbols defined in a system header file, e.g. . The -F option allows specification of a path name prefix that will be used to exclude any symbols defined in a file whose path name begins with that prefix. For example, -F\ will exclude any symbols from all files with a path name starting with \. 6.4.2 -Hheading The -H option takes a string as an argument which will be used as a header in the listing. The default heading is the name of the first raw cross-ref information file specified. 6.4.3 -Llen Specify the length of the paper on which the listing is to be produced, e.g. if the listing is to be printed on 55 line paper you would use a -L55 option. The default is 66 lines. 6.4.4 -Ooutfile Allows specification of the output file name. By default the listing will be written to the standard output and may be redirected in the usual manner. Alternatively outfile may be specified as the output file name. 6.4.5 -Pwidth This option allows the specification of the width to which the listing is to be formatted, e.g. -P132 will format the listing for a 132 column printer. The default is 80 columns. 6.4.6 -Sstoplist The -S option should have as its argument the name of a file containing a list of symbols not to be listed in the cross-reference. Symbols should be listed, one per line in the file. Use the C domain symbols. Multiple stoplists may be supplied with multiple -S options. TABLE 6-4: CREF COMMAND-LINE OPTIONS Option Meaning -Fprefix Exclude symbols from files with a pathname or filename starting with prefix -Hheading Specify a heading for the listing file -Llen Specify the page length for the listing file -Ooutfile Specify the name of the listing file -Pwidth Set the listing width -Sstoplist Read file stoplist and ignore any symbols listed. -Xprefix Exclude any symbols starting with prefix --EDF Specify message file location --EMAX Specify maximum number of errors --MSGDISABLE Specify disabled messages --VER Print version number and stop Utilities  2010 Microchip Technology Inc. DS51865B-page 161 6.4.7 -Xprefix The -X option allows the exclusion of symbols from the listing, based on a prefix given as argument to -X. For example if it was desired to exclude all symbols starting with the character sequence xyz then the option -Xxyz would be used. If a digit appears in the character sequence then this will match any digit in the symbol, e.g. -XX0 would exclude any symbols starting with the letter X followed by a digit. 6.4.8 --EDF=message file: Set Message File Path This option is mainly used by the command-line driver, PICC, to specify the path of the message description file. The default file is located in the dat directory in the compiler’s installation directory. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 6.4.9 --EMAX=number: Specify Maximum Number of Errors This option is mainly used by the command-line driver, PICC, to specify the maximum number of errors that can be encountered before CREF terminates. The default number is 10 errors. This option is applied if compiling using PICC, the command-line driver and the --ERRORS driver option, see Section 2.7.28 “--ERRORS: Maximum Number of Errors”. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 6.4.10 --MSGDISABLE=message numbers Disable Messages This option is mainly used by the command-line driver, PICC, to disable particular message numbers. It takes a comma-separate list of message numbers that will be disabled during compilation. This option is applied if compiling using PICC, the command-line driver and the --MSGDISABLE driver option, see Section 2.7.37 “--MSGDISABLE: Disable Warning Messages”. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 6.4.11 --VER: Print Version Number This option prints information relating to the version and build of CREF. CREF will terminate after processing this option, even if other options and files are present on the command line. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 162  2010 Microchip Technology Inc. 6.5 CROMWELL The CROMWELL utility converts code and symbol files into different formats. These files are typically used by debuggers and allow source-level debugging of code. The output formats available are shown in Table 6-5. The CROMWELL application is automatically executed by the command-line driver when required. The following information is required if running the application manually. The general form of the CROMWELL command is: CROMWELL [options] inputFiles -okey [outputFile] where options can be any of the options shown in Table 6-6. The outputFile (optional) is the name of the output file. The inputFiles are typically the HEX and SYM file. CROMWELL automatically searches for the SDB files and reads those if they are found. The options are further described in the following paragraphs. TABLE 6-5: CROMWELL FORMAT TYPES Key Format cod Bytecraft COD file coff COFF file format elf ELF/DWARF file eomf51 Extended OMF-51 format hitech HI-TECH Software format icoff ICOFF file format ihex Intel HEX file format mcoff Microchip COFF file format omf51 OMF-51 file format pe P&E file format s19 Motorola HEX file format TABLE 6-6: CROMWELL COMMAND-LINE OPTIONS Option Description -Pname[,architecture] Processor name and architecture -N Identify code classes -D Dump input file -C Identify input files only -F Fake local symbols as global -Okey Set the output format -Ikey Set the input format -L List the available formats -E Strip file extensions -B Specify big-endian byte ordering -M Strip underscore character -V Verbose mode --EDF=path Specify message file location --EMAX=number Specify maximum number of errors --MSGDISABLE=list Specify disabled messages --VER Print version number and stop Utilities  2010 Microchip Technology Inc. DS51865B-page 163 6.5.1 -Pname[,architecture] The -P options takes a string which is the name of the processor used. CROMWELL may use this in the generation of the output format selected. Note that to produce output in COFF format an additional argument to this option which also specifies the processor architecture is required. Hence for this format the usage of this option must take the form: -Pname,architecture. Table 6-7 enumerates the architectures supported for producing COFF files. 6.5.2 -N To produce some output file formats (e.g. COFF), CROMWELL requires that the names of the program memory space psect classes be provided. The names of the classes are specified as a comma-separated list. See the map file (Section 5.4 “Map Files”) to determine which classes the linker uses. For example, mid-range devices typically requires -NCODE,CONST,ENTRY,STRING. 6.5.3 -D The -D option is used to display details about the named input file in a human-readable format.This option is useful if you need to check the contents of the file, which are usually binary files. The input file can be one of the file types as shown in Table 6-5. 6.5.4 -C This option will attempt to identify if the specified input files are one of the formats as shown in Table 6-5. If the file is recognized, a confirmation of its type will be displayed. 6.5.5 -F When generating a COD file, this option can be used to force all local symbols to be represented as global symbols. The may be useful where an emulator cannot read local symbol information from the COD file. 6.5.6 -Okey This option specifies the format of the output file. The key can be any of the types listed in Table 6-5. 6.5.7 -Ikey This option can be used to specify the default input file format. The key can be any of the types listed in Table 6-5. TABLE 6-7: ARCHITECTURE ARGUMENTS Architecture Description PIC12 Microchip baseline PIC® MCU chips PIC14 Microchip Mid-Range PIC MCU chips PIC14E Microchip Enhanced Mid-Range PIC MCU chips PIC16 Microchip high-end (17CXXX) PIC MCU chips PIC18 Microchip PIC18 chips PIC24 Microchip PIC24F and PIC24H chips PIC30 Microchip dsPIC30 and dsPIC33 chips HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 164  2010 Microchip Technology Inc. 6.5.8 -L Use this option to show what file format types are supported. A list similar to that given in Table 6-5 will be shown. 6.5.9 -E Use this option to tell CROMWELL to ignore any filename extensions that were given. The default extension will be used instead. 6.5.10 -B In formats that support different endian types, use this option to specify big-endian byte ordering. 6.5.11 -M When generating COD files this option will remove the preceding underscore character from symbols. 6.5.12 -V Turns on verbose mode which will display information about operations CROMWELL is performing. 6.5.13 --EDF=message file: Set Message File Path This option is mainly used by the command-line driver, PICC, to specify the path of the message description file. The default file is located in the dat directory in the compiler’s installation directory. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 6.5.14 --EMAX=number: Specify Maximum Number of Errors This option is mainly used by the command-line driver, PICC, to specify the maximum number of errors that can be encountered before CROMWELL terminates. The default number is 10 errors. This option is applied if compiling using PICC, the command-line driver and the --ERRORS driver option, see Section 2.7.28 “--ERRORS: Maximum Number of Errors”. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 6.5.15 --MSGDISABLE=message numbers Disable Messages This option is mainly used by the command-line driver, PICC, to disable particular message numbers. It takes a comma-separate list of message numbers that will be disabled during compilation. This option is applied if compiling using PICC, the command-line driver and the --MSGDISABLE driver option, see Section 2.7.37 “--MSGDISABLE: Disable Warning Messages”. See Section 2.6 “Compiler Messages” for full information about the compiler’s messaging system. 6.5.16 --VER: Print Version Number This option printed information relating to the version and build of CROMWELL. CROMWELL will terminate after processing this option, even if other options and files are present on the command line. Utilities  2010 Microchip Technology Inc. DS51865B-page 165 6.6 HEXMATE The HEXMATE utility is a program designed to manipulate Intel HEX files. HEXMATE is a post-link stage utility which is automatically invoked by the compiler driver, and that provides the facility to: • Calculate and store variable-length checksum values • Fill unused memory locations with known data sequences • Merge multiple Intel HEX files into one output file • Convert INHX32 files to other INHX formats (e.g. INHX8M) • Detect specific or partial opcode sequences within a HEX file • Find/replace specific or partial opcode sequences • Provide a map of addresses used in a HEX file • Change or fix the length of data records in a HEX file. • Validate checksums within Intel HEX files. Typical applications for HEXMATE might include: • Merging a bootloader or debug module into a main application at build time • Calculating a checksum over a range of program memory and storing its value in program memory or EEPROM • Filling unused memory locations with an instruction to send the PC to a known location if it gets lost. • Storage of a serial number at a fixed address. • Storage of a string (e.g. time stamp) at a fixed address. • Store initial values at a particular memory address (e.g. initialize EEPROM) • Detecting usage of a buggy/restricted instruction • Adjusting HEX file to meet requirements of particular bootloaders 6.6.1 HEXMATE Command Line Options HEXMATE is automatically called by the command line driver, PICC. This is primarily to merge in HEX files with the output generated by the source files, however there are some PICC options which directly map to HEXMATE options, and so other functionality can be requested without having to run HEXMATE explicitly on the command line. For other functionality, the following details the options available when running this application. If HEXMATE is to be run directly, its usage is: HEXMATE [specs,]file1.HEX [[specs,]file2.HEX ... [specs,]fileN.HEX] [options] Where file1.HEX through to fileN.HEX form a list of input Intel HEX files to merge using HEXMATE. If only one HEX file is specified, then no merging takes place, but other functionality is specified by additional options. Table 6-8 lists the command line options that HEXMATE accepts. TABLE 6-8: HEXMATE COMMAND-LINE OPTIONS Option Effect -ADDRESSING Set address fields in all HEXMATE options to use word addressing or other -BREAK Break continuous data so that a new record begins at a set address -CK Calculate and store a checksum value -FILL Program unused locations with a known value -FIND Search and notify if a particular code sequence is detected HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 166  2010 Microchip Technology Inc. The input parameters to HEXMATE are now discussed in greater detail. Note that any integral values supplied to the HEXMATE options should be entered as hexadecimal values without leading 0x or trailing h characters. Note also that any address fields specified in these options are to be entered as byte addresses, unless specified otherwise in the -ADDRESSING option. 6.6.1.1 SPECIFICATIONS,FILENAME.HEX Intel HEX files that can be processed by HEXMATE should be in either INHX32 or INHX8M format. Additional specifications can be applied to each HEX file to put restrictions or conditions on how this file should be processed. If any specifications are used they must precede the filename. The list of specifications will then be separated from the filename by a comma. A range restriction can be applied with the specification rStart-End. A range restriction will cause only the address data falling within this range to be used. For example: r100-1FF,myfile.hex will use myfile.hex as input, but only process data which is addressed within the range 100h-1FFh (inclusive) from that file. An address shift can be applied with the specification sOffset. If an address shift is used, data read from this HEX file will be shifted (by the offset specified) to a new address when generating the output. The offset can be either positive or negative. For example: r100-1FFs2000,myfile.HEX will shift the block of data from 100h-1FFh to the new address range 2100h-21FFh. Be careful when shifting sections of executable code. Program code should only be shifted if it is position independent. 6.6.1.2 + PREFIX When the + operator precedes an argument or input file, the data obtained from that source will be forced into the output file and will overwrite another other data existing at that address range. For example: +input.HEX +-STRING@1000="My string" -FIND...,DELETE Remove the code sequence if it is detected (use with caution) -FIND...,REPLACE Replace the code sequence with a new code sequence -FORMAT Specify maximum data record length or select INHX variant -HELP Show all options or display help message for specific option -LOGFILE Save HEXMATE analysis of output and various results to a file -Ofile Specify the name of the output file -SERIAL Store a serial number or code sequence at a fixed address -SIZE Report the number of bytes of data contained in the resultant HEX image. -STRING Store an ASCII string at a fixed address -STRPACK Store an ASCII string at a fixed address using string packing -W Adjust warning sensitivity + Prefix to any option to overwrite other data in its address range if necessary TABLE 6-8: HEXMATE COMMAND-LINE OPTIONS (CONTINUED) Option Effect Utilities  2010 Microchip Technology Inc. DS51865B-page 167 Ordinarily, HEXMATE will issue an error if two sources try to store differing data at the same location. Using the + operator informs HEXMATE that if more than one data source tries to store data to the same address, the one specified with a + prefix will take priority. 6.6.1.3 -ADDRESSING By default, all address arguments in HEXMATE options expect that values will be entered as byte addresses. In some device architectures the native addressing format may be something other than byte addressing. In these cases it would be much simpler to be able to enter address-components in the device’s native format. To facilitate this, the -ADDRESSING option is used. This option takes exactly one parameter which configures the number of bytes contained per address location. If for example a device’s program memory naturally used a 16-bit (2 byte) word-addressing format, the option -ADDRESSING=2 will configure HEXMATE to interpret all command line address fields as word addresses. The affect of this setting is global and all HEXMATE options will now interpret addresses according to this setting. This option will allow specification of addressing modes from one byte per address to four bytes per address. 6.6.1.4 -BREAK This option takes a comma-separated list of addresses. If any of these addresses are encountered in the HEX file, the current data record will conclude and a new data record will recommence from the nominated address. This can be useful to use new data records to force a distinction between functionally different areas of program space. Some HEX file readers depend on this. 6.6.1.5 -CK The -CK option is for calculating a checksum. The usage of this option is: -CK=start-end@destination [+offset][wWidth][tCode][gAlogithm] where: • start and end specify the address range over which the checksum will be calculated. • destination is the address where the checksum result will be stored. This value cannot be within the range of calculation. • offset is an optional initial value to add to the checksum result. • Width is optional and specifies the byte-width of the checksum result. Results can be calculated for byte-widths of 1 to 4 bytes. If a positive width is requested, the result will be stored in big-endian byte order. A negative width will cause the result to be stored in little-endian byte order. If the width is left unspecified, the result will be 2 bytes wide and stored in little-endian byte order. • Code is a hexadecimal code that will trail each byte in the checksum result. This can allow each byte of the checksum result to be embedded within an instruction. • Algorithm is an integer to select which HEXMATE algorithm to use to calculate the checksum result. A list of selectable algorithms are given in Table 6-9. If unspecified, the default checksum algorithm used is 8 bit addition (1). A typical example of the use of the checksum option is: -CK=0-1FFF@2FFE+2100w2 HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 168  2010 Microchip Technology Inc. This will calculate a checksum over the range 0-1FFFh and program the checksum result at address 2FFEh. The checksum value will be offset by 2100h. The result will be two bytes wide. 6.6.1.6 -FILL The -FILL option is used for filling unused memory locations with a known value. The usage of this option is: -FILL=Code@Start-End[,data] where: • Code is the opcode that will be assigned to unused locations in memory. Multi-byte codes should be entered in little endian order. • Start and End specify the address range over which this fill will apply. • The data flag will specify that only records within the range that contain data will be filled. The default is to fill all records in the range. For example: -FILL=3412@0-1FFF,data will program opcode 1234h in all unused addresses from program memory address 0 to 1FFFh (Note the endianism). This option accepts whole bytes of hexadecimal data from 1 to 8 bytes in length. If the data flag has been specified, HEXMATE will only perform ROM filling to records that actually contain data. This means that these records will be padded out to the default data record length or the width specified in the -FORMAT option. Records will also begin on addresses which are multiples of the data record length used. The default data record length is 16 bytes. This facility is particularly useful or is a requirement for some bootloaders that expect that all data records will be of a particular length and address alignment. 6.6.1.7 -FIND This option is used to detect and log occurrences of an opcode or partial code sequence. The usage of this option is: -FIND=Findcode [mMask]@Start-End [/Align][w][t”Title”] where: • Findcode is the hexadecimal code sequence to search for and is entered in little endian byte order. • Mask is optional. It specifies a bit mask applied over the Findcode value to allow a less restrictive search. It is entered in little endian byte order. TABLE 6-9: HEXMATE CHECKSUM ALGORITHM SELECTION Selector Algorithm description -4 Subtraction of 32 bit values from initial value -3 Subtraction of 24 bit values from initial value -2 Subtraction of 16 bit values from initial value -1 Subtraction of 8 bit values from initial value 1 Addition of 8 bit values from initial value 2 Addition of 16 bit values from initial value 3 Addition of 24 bit values from initial value 4 Addition of 32 bit values from initial value 7 Fletcher’s checksum (8 bit) 8 Fletcher’s checksum (16 bit) Utilities  2010 Microchip Technology Inc. DS51865B-page 169 • Start and End limit the address range to search. • Align is optional. It specifies that a code sequence can only match if it begins on an address which is a multiple of this value. • w, if present, will cause HEXMATE to issue a warning whenever the code sequence is detected. • Title is optional. It allows a title to be given to this code sequence. Defining a title will make log-reports and messages more descriptive and more readable. A title will not affect the actual search results. Here are some examples. The option -FIND=3412@0-7FFF/2w will detect the code sequence 1234h when aligned on a 2 (two) byte address boundary, between 0h and 7FFFh. w indicates that a warning will be issued each time this sequence is found. In this next example, -FIND=3412M0F00@0-7FFF/2wt"ADDXY", the option is the same as in last example but the code sequence being matched is masked with 000Fh, so HEXMATE will search for any of the opcodes 123xh, where x is any digit. If a byte-mask is used, is must be of equal byte-width to the opcode it is applied to. Any messaging or reports generated by HEXMATE will refer to this opcode by the name, ADDXY as this was the title defined for this search. If HEXMATE is generating a log file, it will contain the results of all searches. -FIND accepts whole bytes of HEX data from 1 to 8 bytes in length. Optionally, -FIND can be used in conjunction with REPLACE or DELETE (as described below). 6.6.1.8 -FIND...,DELETE If the DELETE form of the -FIND option is used, any matching sequences will be removed. This function should be used with extreme caution and is not normally recommended for removal of executable code. 6.6.1.9 -FIND...,REPLACE If the REPLACE form of the -FIND option is used, any matching sequences will be replaced, or partially replaced, with new codes. The usage for this sub-option is: -FIND...,REPLACE=Code [mMask] where: • Code is a little endian hexadecimal code to replace the sequences that match the -FIND criteria. • Mask is an optional bit mask to specify which bits within Code will replace the code sequence that has been matched. This may be useful if, for example, it is only necessary to modify 4 bits within a 16-bit instruction. The remaining 12 bits can masked and be left unchanged. 6.6.1.10 -FORMAT The -FORMAT option can be used to specify a particular variant of INHX format or adjust maximum record length. The usage of this option is: -FORMAT=Type [,Length] where: • Type specifies a particular INHX format to generate. • Length is optional and sets the maximum number of bytes per data record. A valid length is between 1 and 16, with 16 being the default. Consider the case of a bootloader trying to download an INHX32 file which fails because it cannot process the extended address records which are part of the INHX32 standard. You know that this bootloader can only program data addressed within the HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 170  2010 Microchip Technology Inc. range 0 to 64k, and that any data in the HEX file outside of this range can be safely disregarded. In this case, by generating the HEX file in INHX8M format the operation might succeed. The HEXMATE option to do this would be -FORMAT=INHX8M. Now consider if the same bootloader also required every data record to contain eight bytes of data, no more, no less. This is possible by combining the -FORMAT with -FILL options. Appropriate use of -FILL can ensure that there are no gaps in the data for the address range being programmed. This will satisfy the minimum data length requirement. To set the maximum length of data records to eight bytes, just modify the previous option to become -FORMAT=INHX8M,8. The possible types that are supported by this option are listed in Table 6-10. Note that INHX032 is not an actual INHX format. Selection of this type generates an INHX32 file but will also initialize the upper address information to zero. This is a requirement of some device programmers. 6.6.1.11 -HELP Using -HELP will list all HEXMATE options. By entering another HEXMATE option as a parameter of -HELP will show a detailed help message for the given option. For example: -HELP=string will show additional help for the -STRING HEXMATE option. 6.6.1.12 -LOGFILE The -LOGFILE option saves HEX file statistics to the named file. For example: -LOGFILE=output.log will analyze the HEX file that HEXMATE is generating and save a report to a file named output.log. 6.6.1.13 -MASK Use this option to logically AND a memory range with a particular bitmask. This is used to ensure that the unimplemented bits in program words (if any) are left blank. The usage of this option is as follows: -MASK=hexcode@start-end Where hexcode is a hexadecimal value that will be ANDed with data within the start to end address range. Multibyte mask values can be entered in little endian byte order. 6.6.1.14 -OFILE The generated Intel HEX output will be created in this file. For example: -Oprogram.hex will save the resultant output to program.hex. The output file can take the same name as one of its input files, but by doing so it will replace the input file entirely. TABLE 6-10: INHX TYPES USED IN -FORMAT OPTION Type Description INHX8M Cannot program addresses beyond 64K INHX32 Can program addresses beyond 64K with extended linear address records INHX032 INHX32 with initialization of upper address to zero Utilities  2010 Microchip Technology Inc. DS51865B-page 171 6.6.1.15 -SERIAL This option will store a particular HEX value at a fixed address. The usage of this option is: -SERIAL=Code [+/-Increment]@Address [+/-Interval][rRepetitions] where: • Code is a hexadecimal value to store and is entered in little endian byte order. • Increment is optional and allows the value of Code to change by this value with each repetition (if requested). • Address is the location to store this code, or the first repetition thereof. • Interval is optional and specifies the address shift per repetition of this code. • Repetitions is optional and specifies the number of times to repeat this code. For example: -SERIAL=000001@EFFE will store HEX code 00001h to address EFFEh. Another example: -SERIAL=0000+2@1000+10r5 will store 5 codes, beginning with value 0000 at address 1000h. Subsequent codes will appear at address intervals of +10h and the code value will change in increments of +2h. 6.6.1.16 -SIZE Using the -SIZE option will report the number of bytes of data within the resultant HEX image to standard output. The size will also be recorded in the log file if one has been requested. 6.6.1.17 -STRING The -STRING option will embed an ASCII string at a fixed address. The usage of this option is: -STRING@Address [tCode]=”Text” where: • Address is the location to store this string. • Code is optional and allows a byte sequence to trail each byte in the string. This can allow the bytes of the string to be encoded within an instruction. • Text is the string to convert to ASCII and embed. For example: -STRING@1000="My favorite string" will store the ASCII data for the string, My favorite string (including the nul character terminator) at address 1000h. And again: -STRING@1000t34="My favorite string" will store the same string with every byte in the string being trailed with the HEX code 34h. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 172  2010 Microchip Technology Inc. 6.6.1.18 -STRPACK This option performs the same function as -STRING but with two important differences. Firstly, only the lower seven bits from each character are stored. Pairs of 7 bit characters are then concatenated and stored as a 14 bit word rather than in separate bytes. This is known as string packing. This is usually only useful for devices where program space is addressed as 14 bit words (PIC10/12/16 devices). The second difference is that -STRING’s t specifier is not applicable with the -STRPACK option. HI-TECH C® FOR PIC10/12/16 USER’S GUIDE  2010 Microchip Technology Inc. DS51865B-page 173 Chapter 7. Library Functions The functions and preprocessor macros within the standard compiler library are alphabetically listed in this chapter. The synopsis indicates the header file in which a declaration or definition for function or macro is found. It also shows the function prototype for functions, or the equivalent prototype for macros. __CONFIG Synopsis #include __CONFIG(data) Description This macro is used to program the configuration fuses that set the device’s operating modes. The macro assumes the argument is a16-bit value, which will be used to program the configuration bits. 16-bit masks have been defined to describe each programmable attribute available on each device. These masks can be found in the chip-specific header files included via . Multiple attributes can be selected by ANDing them together. Example #include __CONFIG(RC & UNPROTECT) void main (void) { } See also __EEPROM_DATA(), __IDLOC(), __IDLOC7() HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 174  2010 Microchip Technology Inc. __DELAY_MS, __DELAY_US Synopsis __delay_ms(x) // request a delay in milliseconds __delay_us(x) // request a delay in microseconds Description As it is often more convenient request a delay in time-based terms rather than in cycle counts, the macros __delay_ms(x) and __delay_us(x) are provided. These macros simply wrap around _delay(n) and convert the time based request into instruction cycles based on the system frequency. In order to achieve this, these macros require the prior definition of preprocessor symbol _XTAL_FREQ. This symbol should be defined as the oscillator frequency (in Hertz) used by the system. An error will result if these macros are used without defining oscillator frequency symbol or if the delay period requested is too large. See also _delay() __EEPROM_DATA Synopsis #include __EEPROM_DATA(a,b,c,d,e,f,g,h) Description This macro is used to store initial values into the device’s EEPROM registers at the time of programming. The macro must be given blocks of 8 bytes to write each time it is called, and can be called repeatedly to store multiple blocks. __EEPROM_DATA() will begin writing to EEPROM address zero, and will auto-increment the address written to by 8, each time it is used. Example #include __EEPROM_DATA(0x00,0x01,0x02,0x03,0x04,0x05,0x06,0x07) __EEPROM_DATA(0x08,0x09,0x0A,0x0B,0x0C,0x0D,0x0E,0x0F) void main (void) { } See also __CONFIG() Library Functions  2010 Microchip Technology Inc. DS51865B-page 175 __IDLOC Synopsis #include __IDLOC(x) Description This macro places data into the device’s special locations outside of addressable memory reserved for ID. This would be useful for storage of serial numbers etc. The macro will attempt to write 4 nibbles of data to the 4 locations reserved for ID purposes. Example #include /* will store 1, 5, F and 0 in the ID registers */ __IDLOC(15F0); void main (void) { } See also __IDLOC7(), __CONFIG() __IDLOC7 Synopsis #include __IDLOC7(a,b,c,d) Description This macro places data into the device’s special locations outside of addressable memory reserved for ID. This would be useful for storage of serial numbers etc. The macro will attempt to write 7 bits of data to each of the 4 locations reserved for ID purposes. Example #include /* will store 7Fh, 70, 1 and 5Ah in the ID registers */ __IDLOC(0x7F,70,1,0x5A); void main (void) { } HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 176  2010 Microchip Technology Inc. Note Not all devices permit 7 bit programming of the ID locations. Refer to the device data sheet to see whether this macro can be used on your particular device. See also __IDLOC(), __CONFIG() _DELAY() Synopsis #include void _delay(unsigned long cycles); Description This is an inline function that is expanded by the code generator. When called, this routine expands to an inline assembly delay sequence. The sequence will consist of code that delays for the number of cycles that is specified as argument. The argument must be a literal constant. An error will result if the delay period requested is too large. For very large delays, call this function multiple times. Example #include void main (void) { control |= 0x80; _delay(10); // delay for 10 cycles control &= 0x7F; } See Also __delay_us(), __delay_ms() Library Functions  2010 Microchip Technology Inc. DS51865B-page 177 ABS Synopsis #include int abs (int j) Description The abs() function returns the absolute value of j. Example #include #include void main (void) { int a = -5; printf(" absolute value of %d is %d\n" a, abs(a)); } See Also labs(), fabs() Return Value The absolute value of j. ACOS Synopsis #include double acos (double f) Description The acos() function implements the inverse of cos(), i.e. it is passed a value in the range -1 to +1, and returns an angle in radians whose cosine is equal to that value. Example #include #include /* Print acos() values for -1 to 1 in degrees. */ void main (void) { float i, a; for(i = -1.0; i < 1.0 ; i += 0.1) { a = acos(i)*180.0/3.141592; printf("(%f) = %f degrees\n" i, a); } HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 178  2010 Microchip Technology Inc. } See Also sin(), cos(), tan(), asin(), atan(), atan2() Return Value An angle in radians, in the range 0 to  ASCTIME Synopsis #include char * asctime (struct tm * t) Description The asctime() function takes the time broken down into the struct tm structure, pointed to by its argument, and returns a 26 character string describing the current date and time in the format: Sun Sep 16 01:03:52 1973\n\0 Note the newline at the end of the string. The width of each field in the string is fixed. The example gets the current time, converts it to a struct tm with localtime(), it then converts this to ASCII and prints it. The time() function will need to be provided by the user (see time() for details). Example #include #include void main (void) { time_t clock; struct tm * tp; time(&clock); tp = localtime(&clock); printf("s" asctime(tp)); } See Also ctime(), gmtime(), localtime(), time() Return Value A to the string. Note The example will require the user to provide the time() routine as it cannot be supplied with the compiler. See time() for more details. Library Functions  2010 Microchip Technology Inc. DS51865B-page 179 ASIN Synopsis #include double asin (double f) Description The asin() function implements the converse of sin(), i.e. it is passed a value in the range -1 to +1, and returns an angle in radians whose sine is equal to that value. Example #include #include void main (void) { float i, a; for(i = -1.0; i < 1.0 ; i += 0.1) { a = asin(i)*180.0/3.141592; printf("(%f) = %f degrees\n" i, a); } } See Also sin(), cos(), tan(), acos(), atan(), atan2() Return Value An angle in radians, in the range -  ASSERT Synopsis #include void assert (int e) Description This macro is used for debugging purposes; the basic method of usage is to place assertions liberally throughout your code at points where correct operation of the code depends upon certain conditions being true initially. An assert() routine may be used to ensure at run time that an assumption holds true. For example, the following statement asserts that the tp is not equal to NULL: assert(tp); If at run time the expression evaluates to false, the program will abort with a message identifying the source file and line number of the assertion, and the expression used as an argument to it. A fuller discussion of the uses of assert() is impossible in limited space, but it is closely linked to methods of proving program correctness. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 180  2010 Microchip Technology Inc. Example void ptrfunc (struct xyz * tp) { assert(tp != 0); } Note When required for ROM based systems, the underlying routine _fassert(...) will need to be implemented by the user. ATAN Synopsis #include double atan (double x) Description This function returns the arc tangent of its argument, i.e. it returns an angle e in the range -  Example #include #include void main (void) { printf("f\n" atan(1.5)); } See Also sin(), cos(), tan(), asin(), acos(), atan2() Return Value The arc tangent of its argument. Library Functions  2010 Microchip Technology Inc. DS51865B-page 181 ATAN2 Synopsis #include double atan2 (double x, double x) Description This function returns the arc tangent of y/x. Example #include #include void main (void) { printf("f\n" atan2(10.0, -10.0)); } See Also sin(), cos(), tan(), asin(), acos(), atan() Return Value The arc tangent of y/x. ATOF Synopsis #include double atof (const char * s) Description The atof() function scans the character string passed to it, skipping leading blanks. It then converts an ASCII representation of a number to a double. The number may be in decimal, normal floating point or scientific notation. Example #include #include void main (void) { char buf[80]; double i; gets(buf); i = atof(buf); printf(" %s: converted to %f\n" buf, i); } HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 182  2010 Microchip Technology Inc. See Also atoi(), atol(), strtod() Return Value A double precision floating-point number. If no number is found in the string, 0.0 will be returned. ATOI Synopsis #include int atoi (const char * s) Description The atoi() function scans the character string passed to it, skipping leading blanks and reading an optional sign. It then converts an ASCII representation of a decimal number to an integer. Example #include #include void main (void) { char buf[80]; int i; gets(buf); i = atoi(buf); printf(" %s: converted to %d\n" buf, i); } See Also xtoi(), atof(), atol() Return Value A signed integer. If no number is found in the string, 0 will be returned. ATOL Synopsis #include long atol (const char * s) Description The atol() function scans the character string passed to it, skipping leading blanks. It then converts an ASCII representation of a decimal number to a long integer. Library Functions  2010 Microchip Technology Inc. DS51865B-page 183 Example #include #include void main (void) { char buf[80]; long i; gets(buf); i = atol(buf); printf(" %s: converted to %ld\n" buf, i); } See Also atoi(), atof() Return Value A long integer. If no number is found in the string, 0 will be returned. BSEARCH Synopsis #include void * bsearch (const void * key, void * base, size_t n_memb, size_t size, int (*compar)(const void *, const void *)) Description The bsearch() function searches a sorted array for an element matching a particular key. It uses a binary search algorithm, calling the function pointed to by compar to compare elements in the array. Example #include #include #include struct value { char name[40]; int value; } values[100]; int val_cmp (const void * p1, const void * p2) { return strcmp(((const struct value *)p1)->name, ((const struct value *)p2)->name); } void main (void) { char inbuf[80]; int i; HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 184  2010 Microchip Technology Inc. struct value * vp; i = 0; while(gets(inbuf)) { sscanf(inbuf,"s %d" values[i].name, &values[i].value); i++; } qsort(values, i, sizeof values[0], val_cmp); vp = bsearch("" values, i, sizeof values[0], val_cmp); if(!vp) printf(" ’fred’ was not found\n"; else printf(" ’fred’ has value %d\n" vp->value); } See Also qsort() Return Value A to the matched array element (if there is more than one matching element, any of these may be returned). If no match is found, a null is returned. Note The comparison function must have the correct prototype. CEIL Synopsis #include double ceil (double f) Description This routine returns the smallest whole number not less than f. Example #include #include void main (void) { double j; scanf("lf" &j); printf(" ceiling of %lf is %lf\n" j, ceil(j)); } Library Functions  2010 Microchip Technology Inc. DS51865B-page 185 CGETS Synopsis #include char * cgets (char * s) Description The cgets() function will read one line of input from the console into the buffer passed as an argument. It does so by repeated calls to getche(). As characters are read, they are buffered, with backspace deleting the previously typed character, and ctrl-U deleting the entire line typed so far. Other characters are placed in the buffer, with a carriage return or line feed (newline) terminating the function. The collected string is null terminated. Example #include #include char buffer[80]; void main (void) { for(;;) { cgets(buffer); if(strcmp(buffer, "" == 0) break; cputs(" ’exit’ to finish\n"; } } See Also getch(), getche(), putch(), cputs() Return Value The return value is the character passed as the sole argument. CLRWDT Synopsis #include CLRWDT(); Description This macro is used to clear the device’s internal watchdog timer. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 186  2010 Microchip Technology Inc. Example #include void main (void) { WDTCON=1; /* enable the WDT */ CLRWDT(); } COS Synopsis #include double cos (double f) Description This function yields the cosine of its argument, which is an angle in radians. The cosine is calculated by expansion of a polynomial series approximation. Example #include #include #define C 3.141592/180.0 void main (void) { double i; for(i = 0 ; i <= 180.0 ; i += 10) printf("(%3.0f) = %f, cos = %f\n" i, sin(i*C), cos(i*C)); } See Also sin(), tan(), asin(), acos(), atan(), atan2() Return Value A double in the range -1 to +1. Library Functions  2010 Microchip Technology Inc. DS51865B-page 187 COSH, SINH, TANH Synopsis #include double cosh (double f) double sinh (double f) double tanh (double f) Description These functions are the implement hyperbolic equivalents of the trigonometric functions; cos(), sin() and tan(). Example #include #include void main (void) { printf("f\n" cosh(1.5)); printf("f\n" sinh(1.5)); printf("f\n" tanh(1.5)); } Return Value The function cosh() returns the hyperbolic cosine value. The function sinh() returns the hyperbolic sine value. The function tanh() returns the hyperbolic tangent value. CPUTS Synopsis #include void cputs (const char * s) Description The cputs() function writes its argument string to the console, outputting carriage returns before each newline in the string. It calls putch() repeatedly. On a hosted system cputs() differs from puts() in that it writes to the console directly, rather than using file I/O. In an embedded system cputs() and puts() are equivalent. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 188  2010 Microchip Technology Inc. Example #include #include char buffer[80]; void main (void) { for(;;) { cgets(buffer); if(strcmp(buffer, "" == 0) break; cputs(" ’exit’ to finish\n"; } } See Also cputs(), puts(), putch() CTIME Synopsis #include char * ctime (time_t * t) Description The ctime() function converts the time in seconds pointed to by its argument to a string of the same form as described for asctime(). Thus the example program prints the current time and date. Example #include #include void main (void) { time_t clock; time(&clock); printf("s" ctime(&clock)); } See Also gmtime(), localtime(), asctime(), time() Return Value A to the string. Note The example will require the user to provide the time() routine as one cannot be supplied with the compiler. See time() for more detail. Library Functions  2010 Microchip Technology Inc. DS51865B-page 189 DEVICE_ID_READ() Synopsis #include unsigned int device_id_read(void); Description This function returns the device ID code that is factory-programmed into the chip. This code can be used to identify the device and its revision number. Example #include void main (void) { unsigned int id_value; unsigned int device_code; unsigned char revision_no; id_value = device_id_read(); /* lower 5 bits represent revision number * upper 11 bits identify device */ device_code = (id_value >> 5); revision_no = (unsigned char)(id_value & 0x1F); } See Also flash_read(), config_read() Return Value device_id_read() returns the 16-Bit factory-programmed device id code used to identify the device type and its revision number. Note The device_id_read() is applicable only to those devices which are capable of reading their own program memory. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 190  2010 Microchip Technology Inc. DI, EI Synopsis #include void ei (void) void di (void) Description The di() and ei() routines disable and re-enable interrupts respectively. These are implemented as macros. The example shows the use of ei() and di() around access to a long variable that is modified during an interrupt. If this was not done, it would be possible to return an incorrect value, if the interrupt occurred between accesses to successive words of the count value. The ei() macro should never be called in an interrupt function, and there is no need to call di() in an interrupt function. Example #include long count; void interrupt tick (void) { count++; } long getticks (void) { long val; /* Disable interrupts around access to count, to ensure consistency.*/ di(); val = count; ei(); return val; } DIV Synopsis #include div_t div (int numer, int demon) Description The div() function computes the quotient and remainder of the numerator divided by the denominator. Library Functions  2010 Microchip Technology Inc. DS51865B-page 191 Example #include #include void main (void) { div_t x; x = div(12345, 66); printf(" = %d, remainder = %d\n" x.quot, x.rem); } See Also udiv(), ldiv(), uldiv() Return Value Returns the quotient and remainder into the div_t structure. EEPROM_READ, EEPROM_WRITE Synopsis #include unsigned char eeprom_read (unsigned int address); void eeprom_write (unsigned int address, unsigned char value); Description These functions allow access to the on-chip eeprom (when present). The eeprom is not in the directly-accessible memory space and a special byte sequence is loaded to the eeprom control registers to access this memory. Writing a value to the eeprom is a slow process and the eeprom_write() function polls the appropriate registers to ensure that any previous writes have completed before writing the next datum. Reading data is completed in the one cycle and no polling is necessary to check for a read completion. Example #include void main (void) { unsigned char data; unsigned int address = 0x0010; data=eeprom_read(address); eeprom_write(address, data); } See Also flash_erase(), flash_read(), flash_write() HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 192  2010 Microchip Technology Inc. Note The high and low priority interrupt are disabled during sensitive sequences required to access EEPROM. Interrupts are restored after the sequence has completed. eeprom_write() will clear the EEIF hardware flag before returning. Both eeprom_read() and eeprom_write() are available in a similar macro form. The essential difference between the macro and function implementations is that EEPROM_READ(), the macro, does not test nor wait for any prior write operations to complete. EVAL_POLY Synopsis #include double eval_poly (double x, const double * d, int n) Description The eval_poly() function evaluates a polynomial, whose coefficients are contained in the array d, at x, for example: y = x*x*d2 + x*d1 + d0. The order of the polynomial is passed in n. Example #include #include void main (void) { double x, y; double d[3] = {1.1, 3.5, 2.7}; x = 2.2; y = eval_poly(x, d, 2); printf(" polynomial evaluated at %f is %f\n" x, y); } Return Value A double value, being the polynomial evaluated at x. EXP Synopsis #include double exp (double f) Description The exp() routine returns the exponential function of its argument, i.e. e to the power of f. Library Functions  2010 Microchip Technology Inc. DS51865B-page 193 Example #include #include void main (void) { double f; for(f = 0.0 ; f <= 5 ; f += 1.0) printf(" to %1.0f = %f\n" f, exp(f)); } See Also log(), log10(), pow() FABS Synopsis #include double fabs (double f) Description This routine returns the absolute value of its double argument. Example #include #include void main (void) { printf("f %f\n" fabs(1.5), fabs(-1.5)); } See Also abs(), labs() FLASH_COPY Synopsis #include void flash_copy(const unsigned char * source_addr, unsigned char length, unsigned short dest_addr); Description This utility function is useful for copying a large section of memory to a new location in Flash memory. Note it is only applicable to those devices which have an internal set of Flash buffer registers. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 194  2010 Microchip Technology Inc. When the function is called, it needs to be supplied with a const to the source address of the data to copy. The may point to a valid address in either RAM or Flash memory. A length parameter must be specified to indicate the number of words of the data to be copied. Finally the Flash address where this data is destined must be specified. Example #include const unsigned char ROMSTRING[] = "" void main (void){ const unsigned char * ptr = &ROMSTRING[0]; flash_copy( ptr, 5, 0x70 ); } See Also EEPROM_READ(), EEPROM_WRITE(), FLASH_READ(), FLASH_WRITE() Note This function is only applicable to those devices which use internal buffer registers when writing to Flash. Ensure that the function does not attempt to overwrite the section of program memory from which it is currently executing, and extreme caution must be exercised if modifying code at the device’s reset or interrupt vectors. A reset or interrupt must not be triggered while this sector is in erasure. FLASH_ERASE(), FLASH_READ() Synopsis #include void flash_erase (unsigned short addr); unsigned int flash_read (unsigned short addr); Description These functions allow access to the Flash memory of the microcontroller (if supported). Reading from the Flash memory can be done one word at a time with use of the flash_read() function. flash_read() returns the data value found at the specified word address in Flash memory. Entire sectors of 32 words can be restored to an unprogrammed state (value=FF) with use of the flash_erase() function. Specifying an address to the flash_erase() function, will erase all 32 words in the sector that contains the given address. Library Functions  2010 Microchip Technology Inc. DS51865B-page 195 Example #include void main (void) { unsigned int data; unsigned short address=0x1000; data = flash_read(address); flash_erase(address); } Return Value flash_read() returns the data found at the given address, as an unsigned int. Note The functions flash_erase() and flash_read() are only available on those devices that support such functionality. FMOD Synopsis #include double fmod (double x, double y) Description The function fmod returns the remainder of x/y as a floating-point quantity. Example #include void main (void) { double rem, x; x = 12.34; rem = fmod(x, 2.1); } Return Value The floating-point remainder of x/y. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 196  2010 Microchip Technology Inc. FLOOR Synopsis #include double floor (double f) Description This routine returns the largest whole number not greater than f. Example #include #include void main (void) { printf("f\n" floor( 1.5 )); printf("f\n" floor( -1.5)); } FREXP Synopsis #include double frexp (double f, int * p) Description The frexp() function breaks a floating-point number into a normalized fraction and an integral power of 2. The integer is stored into the int object pointed to by p. Its return value x is in the interval (0.5, 1.0) or zero, and f equals x times 2 raised to the power stored in *p. If f is zero, both parts of the result are zero. Example #include #include void main (void) { double f; int i; f = frexp(23456.34, &i); printf(".34 = %f * 2^%d\n" f, i); } See Also ldexp() Library Functions  2010 Microchip Technology Inc. DS51865B-page 197 FTOA Synopsis #include char * ftoa (float f, int * status) Description The function ftoa converts the contents of f into a string which is stored into a buffer which is then return. Example #include #include void main (void) { char * buf; float input = 12.34; int status; buf = ftoa(input, &status); printf(" buffer holds %s\n" buf); } See Also strtol(), itoa(), utoa(), ultoa() Return Value This routine returns a reference to the buffer into which the result is written. GETCHAR Synopsis #include int getchar (void) Description The getchar() routine is a getc(stdin) operation. It is a macro defined in stdio.h. Note that under normal circumstances getchar() will NOT return unless a carriage return has been typed on the console. To get a single character immediately from the console, use the function getch(). Example #include void main (void) { int c; while((c = getchar()) != EOF) putchar(c); HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 198  2010 Microchip Technology Inc. } See Also getc(), fgetc(), freopen(), fclose() Note This routine is not usable in a ROM based system. GETS Synopsis #include char * gets (char * s) Description The gets() function reads a line from standard input into the buffer at s, deleting the newline (c.f. fgets()). The buffer is null terminated. In an embedded system, gets() is equivalent to cgets(), and results in getche() being called repeatedly to get characters. Editing (with backspace) is available. Example #include void main (void) { char buf[80]; printf(" a line: "; if(gets(buf)) puts(buf); } See Also fgets(), freopen(), puts() Return Value It returns its argument, or NULL on end-of-file. GET_CAL_DATA Synopsis #include double get_cal_data (const unsigned char * code_ptr) Description This function returns the 32-bit floating-point calibration data from the PIC MCU 14000 calibration space. Only use this function to access KREF, KBG, VHTHERM and KTC (that is, the 32-bit floating-point parameters). FOSC and TWDT can be accessed directly as they are bytes. Library Functions  2010 Microchip Technology Inc. DS51865B-page 199 Example #include void main (void) { double x; unsigned char y; /* Get the slope reference ratio. */ x = get_cal_data(KREF); /* Get the WDT time-out. */ y =TWDT; } Return Value The value of the calibration parameter Note This function can only be used on the PIC14000. GMTIME Synopsis #include struct tm * gmtime (time_t * t) Description This function converts the time pointed to by t which is in seconds since 00:00:00 on Jan 1, 1970, into a broken down time stored in a structure as defined in time.h. The structure is defined in the ’Data Types’ section. Example #include #include void main (void) { time_t clock; struct tm * tp; time(&clock); tp = gmtime(&clock); printf("’s %d in London\n" tp->tm_year+1900); } See Also ctime(), asctime(), time(), localtime() Return Value Returns a structure of type tm. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 200  2010 Microchip Technology Inc. Note The example will require the user to provide the time() routine as one cannot be supplied with the compiler. See time() for more detail. ISALNUM, ISALPHA, ISDIGIT, ISLOWER ET. AL. Synopsis #include int isalnum (char c) int isalpha (char c) int isascii (char c) int iscntrl (char c) int isdigit (char c) int islower (char c) int isprint (char c) int isgraph (char c) int ispunct (char c) int isspace (char c) int isupper (char c) int isxdigit(char c) Description These macros, defined in ctype.h, test the supplied character for membership in one of several overlapping groups of characters. Note that all except isascii() are defined for c, if isascii(c) is true or if c = EOF. isalnum(c) c is in 0-9 or a-z or A-Z isalpha(c) c is in A-Z or a-z isascii(c) c is a 7 bit ascii character iscntrl(c) c is a control character isdigit(c) c is a decimal digit islower(c) c is in a-z isprint(c) c is a printing char isgraph(c) c is a non-space printable character ispunct(c) c is not alphanumeric isspace(c) c is a space, tab or newline isupper(c) c is in A-Z isxdigit(c) c is in 0-9 or a-f or A-F Example #include #include void main (void) { char buf[80]; int i; gets(buf); i = 0; while(isalnum(buf[i])) i++; buf[i] = 0; printf("%s’ is the word\n" buf); } Library Functions  2010 Microchip Technology Inc. DS51865B-page 201 See Also toupper(), tolower(), toascii() ISDIG Synopsis #include int isdig (int c) Description The isdig() function tests the input character c to see if is a decimal digit (0 – 9) and returns true is this is the case; false otherwise. Example #include void main (void) { char buf[] = "" if(isdig(buf[0])) printf(" type detected\n"; } See Also isdigit() (listed under isalnum()) Return Value Zero if the character is a decimal digit; a non-zero value otherwise. ITOA Synopsis #include char * itoa (char * buf, int val, int base) Description The function itoa converts the contents of val into a string which is stored into buf. The conversion is performed according to the radix specified in base. buf is assumed to reference a buffer which has sufficient space allocated to it. Example #include #include void main (void) { char buf[10]; itoa(buf, 1234, 16); printf(" buffer holds %s\n" buf); HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 202  2010 Microchip Technology Inc. } See Also strtol(), utoa(), ltoa(), ultoa() Return Value This routine returns a copy of the buffer into which the result is written. LABS Synopsis #include int labs (long int j) Description The labs() function returns the absolute value of long value j. Example #include #include void main (void) { long int a = -5; printf(" absolute value of %ld is %ld\n" a, labs(a)); } See Also abs() Return Value The absolute value of j. LDEXP Synopsis #include double ldexp (double f, int i) Description The ldexp() function performs the inverse of frexp() operation; the integer i is added to the exponent of the floating-point f and the resultant returned. Library Functions  2010 Microchip Technology Inc. DS51865B-page 203 Example #include #include void main (void) { double f; f = ldexp(1.0, 10); printf(".0 * 2\textasciicircum 10 = %f\n" f); } See Also frexp() Return Value The return value is the integer i added to the exponent of the floating-point value f. LDIV Synopsis #include ldiv_t ldiv (long number, long denom) Description The ldiv() routine divides the numerator by the denominator, computing the quotient and the remainder. The sign of the quotient is the same as that of the mathematical quotient. Its absolute value is the largest integer which is less than the absolute value of the mathematical quotient. The ldiv() function is similar to the div() function, the difference being that the arguments and the members of the returned structure are all of type long int. Example #include #include void main (void) { ldiv_t lt; lt = ldiv(1234567, 12345); printf(" = %ld, remainder = %ld\n" lt.quot, lt.rem); } See Also div(), uldiv(), udiv() Return Value Returns a structure of type ldiv_t HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 204  2010 Microchip Technology Inc. LOCALTIME Synopsis #include struct tm * localtime (time_t * t) Description The localtime() function converts the time pointed to by t which is in seconds since 00:00:00 on Jan 1, 1970, into a broken down time stored in a structure as defined in time.h. The routine localtime() takes into account the contents of the global integer time_zone. This should contain the number of minutes that the local time zone is westward of Greenwich. On systems where it is not possible to predetermine this value, localtime() will return the same result as gmtime(). Example #include #include char * wday[] = { "" "" "" "" "" "" "" }; void main (void) { time_t clock; struct tm * tp; time(&clock); tp = localtime(&clock); printf(" is %s\n" wday[tp->tm_wday]); } See Also ctime(), asctime(), time() Return Value Returns a structure of type tm. Note The example will require the user to provide the time() routine as one cannot be supplied with the compiler. See time() for more detail. Library Functions  2010 Microchip Technology Inc. DS51865B-page 205 LOG, LOG10 Synopsis #include double log (double f) double log10 (double f) Description The log() function returns the natural logarithm of f. The function log10() returns the logarithm to base 10 of f. Example #include #include void main (void) { double f; for(f = 1.0 ; f <= 10.0 ; f += 1.0) printf("(%1.0f) = %f\n" f, log(f)); } See Also exp(), pow() Return Value Zero if the argument is negative. LONGJMP Synopsis #include void longjmp (jmp_buf buf, int val) Description The longjmp() function, in conjunction with setjmp(), provides a mechanism for non-local goto’s. To use this facility, setjmp() should be called with a jmp_buf argument in some outer level function. The call from setjmp() will return 0. To return to this level of execution, longjmp() may be called with the same jmp_buf argument from an inner level of execution. Note however that the function which called setjmp() must still be active when longjmp() is called. Breach of this rule will cause disaster, due to the use of a stack containing invalid data. The val argument to longjmp() will be the value apparently returned from the setjmp(). This should normally be non-zero, to distinguish it from the genuine setjmp() call. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 206  2010 Microchip Technology Inc. Example #include #include #include jmp_buf jb; void inner (void) { longjmp(jb, 5); } void main (void) { int i; if(i = setjmp(jb)) { printf(" returned %d\n" i); exit(0); } printf(" returned 0 - good\n"; printf(" inner...\n"; inner(); printf(" returned - bad!\n"; } See Also setjmp() Return Value The longjmp() routine never returns. Note The function which called setjmp() must still be active when longjmp() is called. Breach of this rule will cause disaster, due to the use of a stack containing invalid data. LTOA Synopsis #include char * ltoa (char * buf, long val, int base) Description The function itoa converts the contents of val into a string which is stored into buf. The conversion is performed according to the radix specified in base. buf is assumed to reference a buffer which has sufficient space allocated to it. Library Functions  2010 Microchip Technology Inc. DS51865B-page 207 Example #include #include void main (void) { char buf[10]; utoi(buf, 12345678L, 16); printf(" buffer holds %s\n" buf); } See Also strtol(), itoa(), utoa(), ultoa() Return Value This routine returns a copy of the buffer into which the result is written. MEMCHR Synopsis #include void * memchr (const void * block, int val, size_t length) Description The memchr() function is similar to strchr() except that instead of searching null-terminated strings, it searches a block of memory specified by length for a particular byte. Its arguments are a to the memory to be searched, the value of the byte to be searched for, and the length of the block. A to the first occurrence of that byte in the block is returned. Example #include #include unsigned int ary[] = {1, 5, 0x6789, 0x23}; void main (void) { char * cp; cp = memchr(ary, 0x89, sizeof ary); if(!cp) printf(" found\n"; else printf(" at offset %u\n" cp - (char *)ary); } See Also strchr() HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 208  2010 Microchip Technology Inc. Return Value A to the first byte matching the argument if one exists; NULL otherwise. MEMCMP Synopsis #include int memcmp (const void * s1, const void * s2, size_t n) Description The memcmp() function compares two blocks of memory, of length n, and returns a signed value similar to strncmp(). Unlike strncmp() the comparison does not stop on a null character. Example #include #include void main (void) { int buf[10], cow[10], i; buf[0] = 1; buf[2] = 4; cow[0] = 1; cow[2] = 5; buf[1] = 3; cow[1] = 3; i = memcmp(buf, cow, 3*sizeof(int)); if(i < 0) printf(" than\n"; else if(i > 0) printf(" than\n"; else printf("\n"; } See Also strncpy(), strncmp(), strchr(), memset(), memchr() Return Value Returns negative one, zero or one, depending on whether s1 points to string which is less than, equal to or greater than the string pointed to by s2 in the collating sequence. Library Functions  2010 Microchip Technology Inc. DS51865B-page 209 MEMCPY Synopsis #include void * memcpy (void * d, const void * s, size_t n) Description The memcpy() function copies n bytes of memory starting from the location pointed to by s to the block of memory pointed to by d. The result of copying overlapping blocks is undefined. The memcpy() function differs from strcpy() in that it copies a specified number of bytes, rather than all bytes up to a null terminator. Example #include #include void main (void) { char buf[80]; memset(buf, 0, sizeof buf); memcpy(buf, " partial string" 10); printf(" = ’%s’\n" buf); } See Also strncpy(), strncmp(), strchr(), memset() Return Value The memcpy() routine returns its first argument. MEMMOVE Synopsis #include void * memmove (void * s1, const void * s2, size_t n) Description The memmove() function is similar to the function memcpy() except copying of overlapping blocks is handled correctly. That is, it will copy forwards or backwards as appropriate to correctly copy one block to another that overlaps it. See Also strncpy(), strncmp(), strchr(), memcpy() Return Value The function memmove() returns its first argument. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 210  2010 Microchip Technology Inc. MEMSET Synopsis #include void * memset (void * s, int c, size_t n) Description The memset() function fills n bytes of memory starting at the location pointed to by s with the byte c. Example #include #include void main (void) { char abuf[20]; strcpy(abuf, " is a string"; memset(abuf, ’x’, 5); printf(" = ’%s’\n" abuf); } See Also strncpy(), strncmp(), strchr(), memcpy(), memchr() MKTIME Synopsis #include time_t mktime (struct tm * tmptr) Description The mktime() function converts the local calendar time referenced by the tm structure tmptr into a time being the number of seconds passed since Jan 1st 1970, or -1 if the time cannot be represented. Example #include #include void main (void) { struct tm birthday; birthday.tm_year = 1955; birthday.tm_mon = 2; birthday.tm_mday = 24; birthday.tm_hour = birthday.tm_min = birthday.tm_sec = 0; printf(" have been alive approximately %ld seconds\n" mktime(&birthday)); Library Functions  2010 Microchip Technology Inc. DS51865B-page 211 } See Also ctime(), asctime() Return Value The time contained in the tm structure represented as the number of seconds since the 1970 Epoch, or -1 if this time cannot be represented. MODF Synopsis #include double modf (double value, double * iptr) Description The modf() function splits the argument value into integral and fractional parts, each having the same sign as value. For example, -3.17 would be split into the integral part (-3) and the fractional part (-0.17). The integral part is stored as a double in the object pointed to by iptr. Example #include #include void main (void) { double i_val, f_val; f_val = modf( -3.17, &i_val); } Return Value The signed fractional part of value. NOP Synopsis #include NOP(); Description Execute NOP instruction here. This is often useful to finetune delays or create a handle for breakpoints. The NOP instruction is sometimes required during some sensitive sequences in hardware. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 212  2010 Microchip Technology Inc. Example #include void crude_delay(unsigned char x) { while(x--){ NOP(); /* Do nothing for 3 cycles */ NOP(); NOP(); } } POW Synopsis #include double pow (double f, double p) Description The pow() function raises its first argument, f, to the power p. Example #include #include void main (void) { double f; for(f = 1.0 ; f <= 10.0 ; f += 1.0) printf("(2, %1.0f) = %f\n" f, pow(2, f)); } See Also log(), log10(), exp() Return Value f to the power of p. PRINTF, VPRINTF Synopsis #include int printf (const char * fmt, ...) #include #include int vprintf (const char * fmt, va_list va_arg) Library Functions  2010 Microchip Technology Inc. DS51865B-page 213 Description The printf() function is a formatted output routine, operating on stdout. The printf() routine is passed a format string, followed by a list of zero or more arguments. In the format string are conversion specifications, each of which is used to print out one of the argument list values. Each conversion specification is of the form %m.nc where the percent symbol % introduces a conversion, followed by an optional width specification m. The n specification is an optional precision specification (introduced by the dot) and c is a letter specifying the type of the conversion. A minus sign (’-’) preceding m indicates left rather than right adjustment of the converted value in the field. Where the field width is larger than required for the conversion, blank padding is performed at the left or right as specified. Where right adjustment of a numeric conversion is specified, and the first digit of m is 0, then padding will be performed with zeroes rather than blanks. For integer formats, the precision indicates a minimum number of digits to be output, with leading zeros inserted to make up this number if required. A hash character (#) preceding the width indicates that an alternate format is to be used. The nature of the alternate format is discussed below. Not all formats have alternates. In those cases, the presence of the hash character has no effect. If the character * is used in place of a decimal constant, e.g. in the format %*d, then one integer argument will be taken from the list to provide that value. The types of conversion are: f Floating point - m is the total width and n is the number of digits after the decimal point. If n is omitted it defaults to 6. If the precision is zero, the decimal point will be omitted unless the alternate format is specified. e Print the corresponding argument in scientific notation. Otherwise similar to f. g Use e or f format, whichever gives maximum precision in minimum width. Any trailing zeros after the decimal point will be removed, and if no digits remain after the decimal point, it will also be removed. o x X u d Integer conversion - in radices 8, 16, 16, 10 and 10 respectively. The conversion is signed in the case of d, unsigned otherwise. The precision value is the total number of digits to print, and may be used to force leading zeroes. E.g. %8.4x will print at least 4 HEX digits in an 8 wide field. Preceding the key letter with an l indicates that the value argument is a long integer. The letter X prints out hexadecimal numbers using the upper case letters A-F rather than a- f as would be printed when using x. When the alternate format is specified, a leading zero will be supplied for the octal format, and a leading 0x or 0X for the HEX format. s Print a string - the value argument is assumed to be a character . At most n characters from the string will be printed, in a field m characters wide. c The argument is assumed to be a single character and is printed literally. Any other characters used as conversion specifications will be printed. Thus % will produce a single percent sign. The vprintf() function is similar to printf() but takes a variable argument list rather than a list of arguments. See the description of va_start() for more information on variable argument lists. An example of using vprintf() is given below. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 214  2010 Microchip Technology Inc. Example printf(" = %4d%" 23) yields ’Total = 23%’ printf(" is %lx", size) where size is a long, prints size as hexadecimal. printf(" = %.8s" "" yields ’Name = a1234567’ printf("%*d" 3, 4) yields ’xx 4’ /* vprintf example */ #include int error (char * s, ...) { va_list ap; va_start(ap, s); printf(": "; vprintf(s, ap); putchar(’\n’); va_end(ap); } void main (void) { int i; i = 3; error(" 1 2 %d" i); } See Also sprintf() Return Value The printf() and vprintf() functions return the number of characters written to stdout. Library Functions  2010 Microchip Technology Inc. DS51865B-page 215 PUTCHAR Synopsis #include int putchar (int c) Description The putchar() function calls putch() to print one character to stdout, and is defined in stdio.h. Example #include char * x = " is a string" void main (void) { char * cp; cp = x; while(*x) putchar(*x++); putchar(’\n’); } See Also putc(), getc(), freopen(), fclose() Return Value The character passed as argument, or EOF if an error occurred. PUTS Synopsis #include int puts (const char * s) Description The puts() function writes the string s to the stdout stream, appending a newline. The null character terminating the string is not copied. Example #include void main (void) { puts(", world!"; } HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 216  2010 Microchip Technology Inc. See Also fputs(), gets(), freopen(), fclose() Return Value EOF is returned on error; zero otherwise. QSORT Synopsis #include void qsort (void * base, size_t nel, size_t width, int (*func)(const void *, const void *)) Description The qsort() function is an implementation of the quicksort algorithm. It sorts an array of nel items, each of length width bytes, located contiguously in memory at base. The argument func is a to a function used by qsort() to compare items. It calls func with s to two items to be compared. If the first item is considered to be greater than, equal to or less than the second then func should return a value greater than zero, equal to zero or less than zero respectively. Example #include #include int array[] = { 567, 23, 456, 1024, 17, 567, 66 }; int sortem (const void * p1, const void * p2) { return *(int *)p1 - *(int *)p2; } void main (void) { register int i; qsort(aray, sizeof array/sizeof array[0], sizeof array[0], sortem); for(i = 0 ; i != sizeof array/sizeof array[0] ; i++) printf("d\t" array[i]); putchar(’\n’); } Note The function parameter must be a to a function of type similar to: int func (const void *, const void *) i.e. it must accept two const void * parameters, and must be prototyped. Library Functions  2010 Microchip Technology Inc. DS51865B-page 217 RAND Synopsis #include int rand (void) Description The rand() function is a pseudo-random number generator. It returns an integer in the range 0 to 32767, which changes in a pseudo-random fashion on each call. The algorithm will produce a deterministic sequence if started from the same point. The starting point is set using the srand() call. The example shows use of the time() function to generate a different starting point for the sequence each time. Example #include #include #include void main (void) { time_t toc; int i; time(&toc); srand((int)toc); for(i = 0 ; i != 10 ; i++) printf("d\t" rand()); putchar(’\n’); } See Also srand() Note The example will require the user to provide the time() routine as one cannot be supplied with the compiler. See time() for more detail. ROUND Synopsis #include double round (double x) Description The round function round the argument to the nearest integer value, but in floating-point format. Values midway between integer values are rounded up. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 218  2010 Microchip Technology Inc. Example #include void main (void) { double input, rounded; input = 1234.5678; rounded = round(input); } See Also trunc() SETJMP Synopsis #include int setjmp (jmp_buf buf) Description The setjmp() function is used with longjmp() for non-local goto’s. See longjmp() for further information. Example #include #include #include jmp_buf jb; void inner (void) { longjmp(jb, 5); } void main (void) { int i; if(i = setjmp(jb)) { printf(" returned %d\n" i); exit(0); } printf(" returned 0 - good\n"; printf(" inner...\n"; inner(); printf(" returned - bad!\n"; } See Also longjmp() Library Functions  2010 Microchip Technology Inc. DS51865B-page 219 Return Value The setjmp() function returns zero after the real call, and non-zero if it apparently returns after a call to longjmp(). SIN Synopsis #include double sin (double f) Description This function returns the sine function of its argument. Example #include #include #define C 3.141592/180.0 void main (void) { double i; for(i = 0 ; i <= 180.0 ; i += 10) printf("(%3.0f) = %f\n" i, sin(i*C)); printf("(%3.0f) = %f\n" i, cos(i*C)); } See Also cos(), tan(), asin(), acos(), atan(), atan2() Return Value Sine vale of f. SLEEP Synopsis #include SLEEP(); Description This macro is used to put the device into a low-power standby mode. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 220  2010 Microchip Technology Inc. Example #include extern void init(void); void main (void) { init(); /* enable peripherals/interrupts */ while(1) SLEEP(); /* save power while nothing happening */ } SPRINTF, VSPRINTF Synopsis #include int sprintf (char * buf, const char * fmt, ...) #include #include int vsprintf (char * buf, const char * fmt, va_list ap) Description The sprintf() function operates in a similar fashion to printf(), except that instead of placing the converted output on the stdout stream, the characters are placed in the buffer at buf. The resultant string will be null terminated, and the number of characters in the buffer will be returned. The vsprintf() function is similar to sprintf() but takes a variable argument list rather than a list of arguments. See the description of va_start() for more information on variable argument lists. See Also printf(), sscanf() Return Value Both these routines return the number of characters placed into the buffer. SQRT Synopsis #include double sqrt (double f) Description The function sqrt(), implements a square root routine using Newton’s approximation. Library Functions  2010 Microchip Technology Inc. DS51865B-page 221 Example #include #include void main (void) { double i; for(i = 0 ; i <= 20.0 ; i += 1.0) printf(" root of %.1f = %f\n" i, sqrt(i)); } See Also exp() Return Value Returns the value of the square root. Note A domain error occurs if the argument is negative. SRAND Synopsis #include void srand (unsigned int seed) Description The srand() function initializes the random number generator accessed by rand() with the given seed. This provides a mechanism for varying the starting point of the pseudo-random sequence yielded by rand(). Example #include #include #include void main (void) { time_t toc; int i; time(&toc); srand((int)toc); for(i = 0 ; i != 10 ; i++) printf("d\t" rand()); putchar(’\n’); } See Also rand() HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 222  2010 Microchip Technology Inc. SSCANF, VSSCANF Synopsis #include int sscanf (const char * buf, const char * fmt, ...) #include #include int vsscanf (const char * buf, const char * fmt, va_list ap) Description The sscanf() function operates in a similar manner to scanf(), except that instead of the conversions being taken from stdin, they are taken from the string at buf. The vsscanf() function takes an argument rather than a list of arguments. See the description of va_start() for more information on variable argument lists. See Also scanf(), fscanf(), sprintf() Return Value Returns the value of EOF if an input failure occurs, else returns the number of input items. STRCAT Synopsis #include char * strcat (char * s1, const char * s2) Description This function appends (concatenates) string s2 to the end of string s1. The result will be null terminated. The argument s1 must point to a character array big enough to hold the resultant string. Example #include #include void main (void) { char buffer[256]; char * s1, * s2; strcpy(buffer, " of line"; s1 = buffer; s2 = "... end of line" strcat(s1, s2); printf(" = %d\n" strlen(buffer)); printf(" = \"s\"n" buffer); } Library Functions  2010 Microchip Technology Inc. DS51865B-page 223 See Also strcpy(), strcmp(), strncat(), strlen() Return Value The value of s1 is returned. STRCHR, STRICHR Synopsis #include char * strchr (const char * s, int c) char * strichr (const char * s, int c) Description The strchr() function searches the string s for an occurrence of the character c. If one is found, a to that character is returned, otherwise NULL is returned. The strichr() function is the case-insensitive version of this function. Example #include #include void main (void) { static char temp[] = " it is..." char c = ’s’; if(strchr(temp, c)) printf(" %c was found in string\n" c); else printf(" character was found in string"; } See Also strrchr(), strlen(), strcmp() Return Value A to the first match found, or NULL if the character does not exist in the string. Note Although the function takes an integer argument for the character, only the lower 8 bits of the value are used. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 224  2010 Microchip Technology Inc. STRCMP, STRICMP Synopsis #include int strcmp (const char * s1, const char * s2) int stricmp (const char * s1, const char * s2) Description The strcmp() function compares its two, null terminated, string arguments and returns a signed integer to indicate whether s1 is less than, equal to or greater than s2. The comparison is done with the standard collating sequence, which is that of the ASCII character set. The stricmp() function is the case-insensitive version of this function. Example #include #include void main (void) { int i; if((i = strcmp("" "") < 0) printf(" is less than ABc\n"; else if(i > 0) printf(" is greater than ABc\n"; else printf(" is equal to ABc\n"; } See Also strlen(), strncmp(), strcpy(), strcat() Return Value A signed integer less than, equal to or greater than zero. Note Other C implementations may use a different collating sequence; the return value is negative, zero or positive, i.e. do not test explicitly for negative one (-1) or one (1). STRCPY Synopsis #include char * strcpy (char * s1, const char * s2) Description This function copies a null terminated string s2 to a character array pointed to by s1. The destination array must be large enough to hold the entire string, including the null terminator. Library Functions  2010 Microchip Technology Inc. DS51865B-page 225 Example #include #include void main (void) { char buffer[256]; char * s1, * s2; strcpy(buffer, " of line"; s1 = buffer; s2 = "... end of line" strcat(s1, s2); printf(" = %d\n" strlen(buffer)); printf(" = \"s\"n" buffer); } See Also strncpy(), strlen(), strcat(), strlen() Return Value The destination buffer s1 is returned. STRCSPN Synopsis #include size_t strcspn (const char * s1, const char * s2) Description The strcspn() function returns the length of the initial segment of the string pointed to by s1 which consists of characters NOT from the string pointed to by s2. Example #include #include void main (void) { static char set[] = "" printf("d\n" strcspn( "" set)); printf("d\n" strcspn( "" set)); printf("d\n" strcspn( "" set)); } See Also strspn() Return Value Returns the length of the segment. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 226  2010 Microchip Technology Inc. STRLEN Synopsis #include size_t strlen (const char * s) Description The strlen() function returns the number of characters in the string s, not including the null terminator. Example #include #include void main (void) { char buffer[256]; char * s1, * s2; strcpy(buffer, " of line"; s1 = buffer; s2 = "... end of line" strcat(s1, s2); printf(" = %d\n" strlen(buffer)); printf(" = \"s\"n" buffer); } Return Value The number of characters preceding the null terminator. STRNCAT Synopsis #include char * strncat (char * s1, const char * s2, size_t n) Description This function appends (concatenates) string s2 to the end of string s1. At most n characters will be copied, and the result will be null terminated. s1 must point to a character array big enough to hold the resultant string. Library Functions  2010 Microchip Technology Inc. DS51865B-page 227 Example #include #include void main (void) { char buffer[256]; char * s1, * s2; strcpy(buffer, " of line"; s1 = buffer; s2 = "... end of line" strncat(s1, s2, 5); printf(" = %d\n" strlen(buffer)); printf(" = \"s\"n" buffer); } See Also strcpy(), strcmp(), strcat(), strlen() Return Value The value of s1 is returned. STRNCMP, STRNICMP Synopsis #include int strncmp (const char * s1, const char * s2, size_t n) int strnicmp (const char * s1, const char * s2, size_t n) Description The strncmp() function compares its two, null terminated, string arguments, up to a maximum of n characters, and returns a signed integer to indicate whether s1 is less than, equal to or greater than s2. The comparison is done with the standard collating sequence, which is that of the ASCII character set. The strnicmp() function is the case-insensitive version of this function. Example #include #include void main (void) { int i; i = strncmp("" ""6); if(i == 0) printf(" strings are equal\n"; else if(i > 0) printf(" 2 less than string 1\n"; else printf(" 2 is greater than string 1\n"; HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 228  2010 Microchip Technology Inc. } See Also strlen(), strcmp(), strcpy(), strcat() Return Value A signed integer less than, equal to or greater than zero. Note Other C implementations may use a different collating sequence; the return value is negative, zero or positive, i.e. do not test explicitly for negative one (-1) or one (1). STRNCPY Synopsis #include char * strncpy (char * s1, const char * s2, size_t n) Description This function copies a null terminated string s2 to a character array pointed to by s1. At most n characters are copied. If string s2 is longer than n then the destination string will not be null terminated. The destination array must be large enough to hold the entire string, including the null terminator. Example #include #include void main (void) { char buffer[256]; char * s1, * s2; strncpy(buffer, " of line" 6); s1 = buffer; s2 = "... end of line" strcat(s1, s2); printf(" = %d\n" strlen(buffer)); printf(" = \"s\"n" buffer); } See Also strcpy(), strcat(), strlen(), strcmp() Return Value The destination buffer s1 is returned. Library Functions  2010 Microchip Technology Inc. DS51865B-page 229 STRPBRK Synopsis #include char * strpbrk (const char * s1, const char * s2) Description The strpbrk() function returns a to the first occurrence in string s1 of any character from string s2, or a null if no character from s2 exists in s1. Example #include #include void main (void) { char * str = " is a string." while(str != NULL) { printf( "s\n" str ); str = strpbrk( str+1, ""); } } Return Value to the first matching character, or NULL if no character found. STRRCHR, STRRICHR Synopsis #include char * strrchr (char * s, int c) char * strrichr (char * s, int c) Description The strrchr() function is similar to the strchr() function, but searches from the end of the string rather than the beginning, i.e. it locates the last occurrence of the character c in the null terminated string s. If successful it returns a to that occurrence, otherwise it returns NULL. The strrichr() function is the case-insensitive version of this function. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 230  2010 Microchip Technology Inc. Example #include #include void main (void) { char * str = " is a string." while(str != NULL) { printf( "s\n" str ); str = strrchr( str+1, ’s’); } } See Also strchr(), strlen(), strcmp(), strcpy(), strcat() Return Value A to the character, or NULL if none is found. STRSPN Synopsis #include size_t strspn (const char * s1, const char * s2) Description The strspn() function returns the length of the initial segment of the string pointed to by s1 which consists entirely of characters from the string pointed to by s2. Example #include #include void main (void) { printf("d\n" strspn(" is a string" ""); printf("d\n" strspn(" is a string" ""); } See Also strcspn() Return Value The length of the segment. Library Functions  2010 Microchip Technology Inc. DS51865B-page 231 STRSTR, STRISTR Synopsis #include char * strstr (const char * s1, const char * s2) char * stristr (const char * s1, const char * s2) Description The strstr() function locates the first occurrence of the sequence of characters in the string pointed to by s2 in the string pointed to by s1. The stristr() routine is the case-insensitive version of this function. Example #include #include void main (void) { printf("d\n" strstr(" is a string" ""); } Return Value to the located string or a null if the string was not found. STRTOD Synopsis #include double strtok (const char * s, const char ** res) Description Parse the string s converting it to a double floating-point type. This function converts the first occurrence of a substring of the input that is made up of characters of the expected form after skipping leading white-space characters. If res is not NULL, it will be made to point to the first character after the converted sub-string. Example #include #include void main (void) { char buf[] = "35.7 23.27 " char * end; double in1, in2; in1 = strtod(buf, &end); in2 = strtod(end, NULL); printf(" comps: %f, %f\n" in1, in2); } HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 232  2010 Microchip Technology Inc. See Also atof() Return Value Returns a double representing the floating-point value of the converted input string. STRTOL Synopsis #include double strtol (const char * s, const char ** res, int base) Description Parse the string s converting it to a long integer type. This function converts the first occurrence of a substring of the input that is made up of characters of the expected form after skipping leading white-space characters. The radix of the input is determined from base. If this is zero, then the radix defaults to base 10. If res is not NULL, it will be made to point to the first character after the converted sub-string. Example #include #include void main (void) { char buf[] = "0X299 0x792 " char * end; long in1, in2; in1 = strtol(buf, &end, 16); in2 = strtol(end, NULL, 16); printf(" (decimal): %ld, %ld\n" in1, in2); } See Also strtod() Return Value Returns a long int representing the value of the converted input string using the specified base. STRTOK Synopsis #include char * strtok (char * s1, const char * s2) Library Functions  2010 Microchip Technology Inc. DS51865B-page 233 Description A number of calls to strtok() breaks the string s1 (which consists of a sequence of zero or more text tokens separated by one or more characters from the separator string s2) into its separate tokens. The first call must have the string s1. This call returns a to the first character of the first token, or NULL if no tokens were found. The inter-token separator character is overwritten by a null character, which terminates the current token. For subsequent calls to strtok(), s1 should be set to a NULL . These calls start searching from the end of the last token found, and again return a to the first character of the next token, or NULL if no further tokens were found. Example #include #include void main (void) { char * ptr; char buf[] = " is a string of words." char * sep_tok = ",?! " ptr = strtok(buf, sep_tok); while(ptr != NULL) { printf("s\n" ptr); ptr = strtok(NULL, sep_tok); } } Return Value Returns a to the first character of a token, or a null if no token was found. Note The separator string s2 may be different from call to call. TAN Synopsis #include double tan (double f) Description The tan() function calculates the tangent of f. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 234  2010 Microchip Technology Inc. Example #include #include #define C 3.141592/180.0 void main (void) { double i; for(i = 0 ; i <= 180.0 ; i += 10) printf("(%3.0f) = %f\n" i, tan(i*C)); } See Also sin(), cos(), asin(), acos(), atan(), atan2() Return Value The tangent of f. TIME Synopsis #include time_t time (time_t * t) Description This function is not provided as it is dependant on the target system supplying the current time. This function will be user implemented. When implemented, this function should return the current time in seconds since 00:00:00 on Jan 1, 1970. If the argument t is not equal to NULL, the same value is stored into the object pointed to by t. Example #include #include void main (void) { time_t clock; time(&clock); printf("s" ctime(&clock)); } See Also ctime(), gmtime(), localtime(), asctime() Return Value This routine when implemented will return the current time in seconds since 00:00:00 on Jan 1, 1970. Library Functions  2010 Microchip Technology Inc. DS51865B-page 235 Note The time() routine is not supplied, if required the user will have to implement this routine to the specifications outlined above. TOLOWER, TOUPPER, TOASCII Synopsis #include char toupper (int c) char tolower (int c) char toascii (int c) Description The toupper() function converts its lower case alphabetic argument to upper case, the tolower() routine performs the reverse conversion and the toascii() macro returns a result that is guaranteed in the range 0-0177. The functions toupper() and tolower() return their arguments if it is not an alphabetic character. Example #include #include #include void main (void) { char * array1 = "" int i; for(i=0;i < strlen(array1); ++i) { printf("c" tolower(array1[i])); } printf("n"; } See Also islower(), isupper(), isascii(), et. al. TRUNC Synopsis #include double trunc (double x) Description The trunc function rounds the argument to the nearest integer value, in floating-point format, that is not larger in magnitude than the argument. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 236  2010 Microchip Technology Inc. Example #include void main (void) { double input, rounded; input = 1234.5678; rounded = trunc(input); } See Also round() UDIV Synopsis #include int udiv (unsigned num, unsigned demon) Description The udiv() function calculate the quotient and remainder of the division of number and denom, storing the results into a udiv_t structure which is returned. Example #include void main (void) { udiv_t result; unsigned num = 1234, den = 7; result = udiv(num, den); } See Also uldiv(), div(), ldiv() Return Value Returns the quotient and remainder as a udiv_t structure. ULDIV Synopsis #include int uldiv (unsigned long num, unsigned long demon) Description The uldiv() function calculate the quotient and remainder of the division of number and denom, storing the results into a uldiv_t structure which is returned. Library Functions  2010 Microchip Technology Inc. DS51865B-page 237 Example #include void main (void) { uldiv_t result; unsigned long num = 1234, den = 7; result = uldiv(num, den); } See Also ldiv(), udiv(), div() Return Value Returns the quotient and remainder as a uldiv_t structure. UTOA Synopsis #include char * utoa (char * buf, unsigned val, int base) Description The function itoa() converts the unsigned contents of val into a string which is stored into buf. The conversion is performed according to the radix specified in base. buf is assumed to reference a buffer which has sufficient space allocated to it. Example #include #include void main (void) { char buf[10]; utoi(buf, 1234, 16); printf(" buffer holds %s\n" buf); } See Also strtol(), itoa(), ltoa(), ultoa() Return Value This routine returns a copy of the buffer into which the result is written. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 238  2010 Microchip Technology Inc. VA_START, VA_ARG, VA_END Synopsis #include void va_start (va_list ap, parmN) type va_arg (ap, type) void va_end (va_list ap) Description These macros are provided to give access in a portable way to parameters to a function represented in a prototype by the ellipsis symbol (...), where type and number of arguments supplied to the function are not known at compile time. The right most parameter to the function (shown as parmN) plays an important role in these macros, as it is the starting point for access to further parameters. In a function taking variable numbers of arguments, a variable of type va_list should be declared, then the macro va_start() invoked with that variable and the name of parmN. This will initialize the variable to allow subsequent calls of the macro va_arg() to access successive parameters. Each call to va_arg() requires two arguments; the variable previously defined and a type name which is the type that the next parameter is expected to be. Note that any arguments thus accessed will have been widened by the default conventions to int, unsigned int or double. For example if a character argument has been passed, it should be accessed by va_arg(ap, int) since the char will have been widened to int. An example is given below of a function taking one integer parameter, followed by a number of other parameters. In this example the function expects the subsequent parameters to be s to char, but note that the compiler is not aware of this, and it is the programmers responsibility to ensure that correct arguments are supplied. Example #include #include void pf (int a, ...) { va_list ap; va_start(ap, a); while(a--) puts(va_arg(ap, char *)); va_end(ap); } void main (void) { pf(3, " 1" " 2" " 3"; } Library Functions  2010 Microchip Technology Inc. DS51865B-page 239 XTOI Synopsis #include unsigned xtoi (const char * s) Description The xtoi() function scans the character string passed to it, skipping leading blanks reading an optional sign, and converts an ASCII representation of a hexadecimal number to an integer. Example #include #include void main (void) { char buf[80]; int i; gets(buf); i = xtoi(buf); printf(" %s: converted to %x\n" buf, i); } See Also atoi() Return Value An unsigned integer. If no number is found in the string, zero will be returned. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 240  2010 Microchip Technology Inc. NOTES: HI-TECH C® FOR PIC10/12/16 USER’S GUIDE  2010 Microchip Technology Inc. DS51865B-page 241 Chapter 8. Error and Warning Messages This chapter lists error, warning and advisory messages with an explanation of each message. This is the complete and historical message set covering all HI-TECH C compilers and all compiler versions. As a result not all messages shown here may be relevant for the compiler, or compiler version, you are using. Most messages have been assigned a unique number which appears in brackets before each message description, and which is also printed by the compiler when the message is issued. The messages shown here are sorted by their number. Un-numbered messages appear toward the end and are sorted alphabetically. The name of the application(s) that could have produced the messages are listed in brackets opposite the error message. In some cases examples of code or options that could trigger the error are given. The use of * in the error message is used to represent a string that the compiler will substitute that is specific to that particular error. Note that one problem in your C or assembler source code may trigger more than one error message. You should attempt to resolve errors or warnings in the order in which they are produced. (1) too many errors (*) (all applications) The executing compiler application has encountered too many errors and will exit immediately. Other uncompiled source files will be processed, but the compiler applications that would normally be executed in due course will not be run. The number of errors that can be accepted can be controlled using the --ERRORS option, See Section 2.7.28 “--ERRORS: Maximum Number of Errors”. (2) error/warning (*) generated, but no description available (all applications) The executing compiler application has emitted a message (advisory/warning/error), but there is no description available in the message description file (MDF) to print. This may be because the MDF is out of date, or the message issue has not been translated into the selected language. (3) malformed error information on line *, in file * (all applications) The compiler has attempted to load the messages for the selected language, but the message description file (MDF) was corrupted and could not be read correctly. (100) unterminated #if[n][def] block from line * (Preprocessor) A #if or similar block was not terminated with a matching #endif, e.g.: #if INPUT /* error flagged here */ void main(void) { run(); } /* no #endif was found in this module */ HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 242  2010 Microchip Technology Inc. (101) #* may not follow #else (Preprocessor) A #else or #elif has been used in the same conditional block as a #else. These can only follow a #if, e.g.: #ifdef FOO result = foo; #else result = bar; #elif defined(NEXT) /* the #else above terminated the #if */ result = next(0); #endif (102) #* must be in an #if (Preprocessor) The #elif, #else or #endif directive must be preceded by a matching #if line. If there is an apparently corresponding #if line, check for things like extra #endif’s, or improperly terminated comments, e.g.: #ifdef FOO result = foo; #endif result = bar; #elif defined(NEXT) /* the #endif above terminated the #if */ result = next(0); #endif (103) #error: * (Preprocessor) This is a programmer generated error; there is a directive causing a deliberate error. This is normally used to check compile time defines etc. Remove the directive to remove the error, but first check as to why the directive is there. (104) preprocessor #assert failure (Preprocessor) The argument to a preprocessor #assert directive has evaluated to zero. This is a programmer induced error. #assert SIZE == 4 /* size should never be 4 */ (105) no #asm before #endasm (Preprocessor) A #endasm operator has been encountered, but there was no previous matching #asm, e.g.: void cleardog(void) { clrwdt #endasm /* in-line assembler ends here, only where did it begin? */ } (106) nested #asm directives (Preprocessor) It is not legal to nest #asm directives. Check for a missing or misspelt #endasm directive, e.g.: #asm MOVE r0, #0aah #asm ; previous #asm must be closed before opening another SLEEP #endasm  2010 Microchip Technology Inc. DS51865B-page 243 (107) illegal # directive "*" (Preprocessor, Parser) The compiler does not understand the # directive. It is probably a misspelling of a pre-processor # directive, e.g.: #indef DEBUG /* oops -- that should be #undef DEBUG */ (108) #if[n][def] without an argument (Preprocessor) The preprocessor directives #if, #ifdef and #ifndef must have an argument. The argument to #if should be an expression, while the argument to #ifdef or #ifndef should be a single name, e.g.: #if /* oops -- no argument to check */ output = 10; #else output = 20; #endif (109) #include syntax error (Preprocessor) The syntax of the filename argument to #include is invalid. The argument to #include must be a valid file name, either enclosed in double quotes "" or angle brackets < >. Spaces should not be included, and the closing quote or bracket must be present. There should be nothing else on the line other than comments, e.g.: #include stdio.h /* oops -- should be: #include */ (110) too many file arguments; usage: cpp [input [output]] (Preprocessor) CPP should be invoked with at most two file arguments. Contact HI-TECH Support if the preprocessor is being executed by a compiler driver. (111) redefining preprocessor macro "*" (Preprocessor) The macro specified is being redefined, to something different to the original definition. If you want to deliberately redefine a macro, use #undef first to remove the original definition, e.g.: #define ONE 1 /* elsewhere: */ /* Is this correct? It will overwrite the first definition. */ #define ONE one (112) #define syntax error (Preprocessor) A macro definition has a syntax error. This could be due to a macro or formal parameter name that does not start with a letter or a missing closing parenthesis, ), e.g.: #define FOO(a, 2b) bar(a, 2b) /* 2b is not to be! */ (113) unterminated string in preprocessor macro body (Preprocessor, Assembler) A macro definition contains a string that lacks a closing quote. (114) illegal #undef argument (Preprocessor) The argument to #undef must be a valid name. It must start with a letter, e.g.: #undef 6YYY /* this isn’t a valid symbol name */ HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 244  2010 Microchip Technology Inc. (115) recursive preprocessor macro definition of "*" defined by "*" (Preprocessor) The named macro has been defined in such a manner that expanding it causes a recursive expansion of itself! (116) end of file within preprocessor macro argument from line * (Preprocessor) A macro argument has not been terminated. This probably means the closing parenthesis has been omitted from a macro invocation. The line number given is the line where the macro argument started, e.g.: #define FUNC(a, b) func(a+b) FUNC(5, 6; /* oops -- where is the closing bracket? */ (117) misplaced constant in #if (Preprocessor) A constant in a #if expression should only occur in syntactically correct places. This error is most probably caused by omission of an operator, e.g.: #if FOO BAR /* oops -- did you mean: #if FOO == BAR ? */ (118) stack overflow processing #if expression (Preprocessor) The preprocessor filled up its expression evaluation stack in a #if expression. Simplify the expression — it probably contains too many parenthesized subexpressions. (119) invalid expression in #if line (Preprocessor) This is an internal compiler error. Contact HI-TECH Software technical support with details. (120) operator "*" in incorrect context (Preprocessor) An operator has been encountered in a #if expression that is incorrectly placed, e.g. two binary operators are not separated by a value, e.g.: #if FOO * % BAR == 4 /* what is “* %” ? */ #define BIG #endif (121) expression stack overflow at operator "*" (Preprocessor) Expressions in #if lines are evaluated using a stack with a size of 128. It is possible for very complex expressions to overflow this. Simplify the expression. (122) unbalanced parenthesis at operator "*" (Preprocessor) The evaluation of a #if expression found mismatched parentheses. Check the expression for correct parenthesizing, e.g.: #if ((A) + (B) /* oops -- a missing ), I think */ #define ADDED #endif (123) misplaced "?" or ":"; previous operator is "*" (Preprocessor) A colon operator has been encountered in a #if expression that does not match up with a corresponding ? operator, e.g.: #if XXX : YYY /* did you mean: #if COND ? XXX : YYY */  2010 Microchip Technology Inc. DS51865B-page 245 (124) illegal character "*" in #if (Preprocessor) There is a character in a #if expression that has no business being there. Valid characters are the letters, digits and those comprising the acceptable operators, e.g.: #if YYY /* what are these characters doing here? */ int m; #endif (125) illegal character (* decimal) in #if (Preprocessor) There is a non-printable character in a #if expression that has no business being there. Valid characters are the letters, digits and those comprising the acceptable operators, e.g.: #if ^S YYY /* what is this control characters doing here? */ int m; #endif (126) strings can’t be used in #if (Preprocessor) The preprocessor does not allow the use of strings in #if expressions, e.g.: /* no string operations allowed by the preprocessor */ #if MESSAGE > “hello” #define DEBUG #endif (127) bad syntax for defined() in #[el]if (Preprocessor) The defined() pseudo-function in a preprocessor expression requires its argument to be a single name. The name must start with a letter and should be enclosed in parentheses, e.g.: /* oops -- defined expects a name, not an expression */ #if defined(a&b) input = read(); #endif (128) illegal operator in #if (Preprocessor) A #if expression has an illegal operator. Check for correct syntax, e.g.: #if FOO = 6 /* oops -- should that be: #if FOO == 5 ? */ (129) unexpected "\" in #if (Preprocessor) The backslash is incorrect in the #if statement, e.g.: #if FOO == \34 #define BIG #endif (130) unknown type "*" in #[el]if sizeof() (Preprocessor) An unknown type was used in a preprocessor sizeof(). The preprocessor can only evaluate sizeof() with basic types, or pointers to basic types, e.g.: #if sizeof(unt) == 2 /* should be: #if sizeof(int) == 2 */ i = 0xFFFF; #endif (131) illegal type combination in #[el]if sizeof() (Preprocessor) The preprocessor found an illegal type combination in the argument to sizeof() in a #if expression, e.g. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 246  2010 Microchip Technology Inc. /* To sign, or not to sign, that is the error. */ #if sizeof(signed unsigned int) == 2 i = 0xFFFF; #endif (132) no type specified in #[el]if sizeof() (Preprocessor) Sizeof() was used in a preprocessor #if expression, but no type was specified. The argument to sizeof() in a preprocessor expression must be a valid simple type, or pointer to a simple type, e.g.: #if sizeof() /* oops -- size of what? */ i = 0; #endif (133) unknown type code (0x*) in #[el]if sizeof() (Preprocessor) The preprocessor has made an internal error in evaluating a sizeof() expression. Check for a malformed type specifier. This is an internal error. Contact HI-TECH Software technical support with details. (134) syntax error in #[el]if sizeof() (Preprocessor) The preprocessor found a syntax error in the argument to sizeof , in a #if expression. Probable causes are mismatched parentheses and similar things, e.g.: #if sizeof(int == 2) // oops - should be: #if sizeof(int) == 2 i = 0xFFFF; #endif (135) unknown operator (*) in #if (Preprocessor) The preprocessor has tried to evaluate an expression with an operator it does not understand. This is an internal error. Contact HI-TECH Software technical support with details. (137) strange character "*" after ## (Preprocessor) A character has been seen after the token catenation operator ## that is neither a letter nor a digit. Since the result of this operator must be a legal token, the operands must be tokens containing only letters and digits, e.g.: /* the ’ character will not lead to a valid token */ #define cc(a, b) a ## ’b (138) strange character (*) after ## (Preprocessor) An unprintable character has been seen after the token catenation operator ## that is neither a letter nor a digit. Since the result of this operator must be a legal token, the operands must be tokens containing only letters and digits, e.g.: /* the ’ character will not lead to a valid token */ #define cc(a, b) a ## ’b (139) end of file in comment (Preprocessor) End of file was encountered inside a comment. Check for a missing closing comment flag, e.g.: /* Here the comment begins. I’m not sure where I end, though }  2010 Microchip Technology Inc. DS51865B-page 247 (140) can’t open * file "*": * (Driver, Preprocessor, Code Generator, Assembler) The command file specified could not be opened for reading. Confirm the spelling and path of the file specified on the command line, e.g.: picc @communds should that be: picc @commands (141) can’t open * file "*": * (Any) An output file could not be created. Confirm the spelling and path of the file specified on the command line. (144) too many nested #if blocks (Preprocessor) #if , #ifdef etc. blocks may only be nested to a maximum of 32. (146) #include filename too long (Preprocessor) A filename constructed while looking for an include file has exceeded the length of an internal buffer. Since this buffer is 4096 bytes long, this is unlikely to happen. (147) too many #include directories specified (Preprocessor) A maximum of 7 directories may be specified for the preprocessor to search for include files. The number of directories specified with the driver is too great. (148) too many arguments for preprocessor macro (Preprocessor) A macro may only have up to 31 parameters, as per the C Standard. (149) preprocessor macro work area overflow (Preprocessor) The total length of a macro expansion has exceeded the size of an internal table. This table is normally 32768 bytes long. Thus any macro expansion must not expand into a total of more than 32K bytes. (150) illegal "__" preprocessor macro "*" (Preprocessor) This is an internal compiler error. Contact HI-TECH Software technical support with details. (151) too many arguments in preprocessor macro expansion (Preprocessor) There were too many arguments supplied in a macro invocation. The maximum number allowed is 31. (152) bad dp/nargs in openpar(): c = * (Preprocessor) This is an internal compiler error. Contact HI-TECH Software technical support with details. (153) out of space in preprocessor macro "*" argument expansion (Preprocessor) A macro argument has exceeded the length of an internal buffer. This buffer is normally 4096 bytes long. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 248  2010 Microchip Technology Inc. (155) work buffer overflow concatenating "*" (Preprocessor) This is an internal compiler error. Contact HI-TECH Software technical support with details. (156) work buffer "*" overflow (Preprocessor) This is an internal compiler error. Contact HI-TECH Software technical support with details. (157) can’t allocate * bytes of memory (Code Generator, Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (158) invalid disable in preprocessor macro "*" (Preprocessor) This is an internal compiler error. Contact HI-TECH Software technical support with details. (159) too many calls to unget() (Preprocessor) This is an internal compiler error. Contact HI-TECH Software technical support with details. (161) control line "*" within preprocessor macro expansion (Preprocessor) A preprocessor control line (one starting with a #) has been encountered while expanding a macro. This should not happen. (162) #warning: * (Preprocessor, Driver) This warning is either the result of user-defined #warning preprocessor directive or the driver encountered a problem reading the map file. If the latter then please HI-TECH Software technical support with details (163) unexpected text in control line ignored (Preprocessor) This warning occurs when extra characters appear on the end of a control line, e.g. The extra text will be ignored, but a warning is issued. It is preferable (and in accordance with Standard C) to enclose the text as a comment, e.g.: #if defined(END) #define NEXT #endif END /* END would be better in a comment here */ (164) #include filename "*" was converted to lower case (Preprocessor) The #include file name had to be converted to lowercase before it could be opened, e.g.: #include /* oops -- should be: #include */ (165) #include filename "*" does not match actual name (check upper/lower case) (Preprocessor) In Windows versions this means the file to be included actually exists and is spelt the same way as the #include filename, however the case of each does not exactly match. For example, specifying #include “code.c” will include Code.c if it is found. In Linux versions this warning could occur if the file wasn’t found.  2010 Microchip Technology Inc. DS51865B-page 249 (166) too few values specified with option "*" (Preprocessor) The list of values to the preprocessor (CPP) -S option is incomplete. This should not happen if the preprocessor is being invoked by the compiler driver. The values passes to this option represent the sizes of char , short , int , long , float and double types. (167) too many values specified with -S option; "*" unused (Preprocessor) There were too many values supplied to the -S preprocessor option. See message 166.. (168) unknown option "*" (Any) This option given to the component which caused the error is not recognized. (169) strange character (*) after ## (Preprocessor) There is an unexpected character after #. (170) symbol "*" in undef was never defined (Preprocessor) The symbol supplied as argument to #undef was not already defined. This warning may be disabled with some compilers. This warning can be avoided with code like: #ifdef SYM #undef SYM /* only undefine if defined */ #endif (171) wrong number of preprocessor macro arguments for "*" (* instead of *) (Preprocessor) A macro has been invoked with the wrong number of arguments, e.g.: #define ADD(a, b) (a+b) ADD(1, 2, 3) /* oops -- only two arguments required */ (172) formal parameter expected after # (Preprocessor) The stringization operator # (not to be confused with the leading # used for preprocessor control lines) must be followed by a formal macro parameter, e.g.: #define str(x) #y /* oops -- did you mean x instead of y? */ If you need to stringize a token, you will need to define a special macro to do it, e.g. #define __mkstr__(x) #x then use __mkstr__(token) wherever you need to convert a token into a string. (173) undefined symbol "*" in #if, 0 used (Preprocessor) A symbol on a #if expression was not a defined preprocessor macro. For the purposes of this expression, its value has been taken as zero. This warning may be disabled with some compilers. Example: #if FOO+BAR /* e.g. FOO was never #defined */ #define GOOD #endif (174) multi-byte constant "*" isn’t portable (Preprocessor) Multi-byte constants are not portable, and in fact will be rejected by later passes of the compiler, e.g.: #if CHAR == ’ab’ HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 250  2010 Microchip Technology Inc. #define MULTI #endif (175) division by zero in #if; zero result assumed (Preprocessor) Inside a #if expression, there is a division by zero which has been treated as yielding zero, e.g.: #if foo/0 /* divide by 0: was this what you were intending? */ int a; #endif (176) missing newline (Preprocessor) A new line is missing at the end of the line. Each line, including the last line, must have a new line at the end. This problem is normally introduced by editors. (177) symbol "*" in -U option was never defined (Preprocessor) A macro name specified in a -U option to the preprocessor was not initially defined, and thus cannot be undefined. (179) nested comments (Preprocessor) This warning is issued when nested comments are found. A nested comment may indicate that a previous closing comment marker is missing or malformed, e.g.: output = 0; /* a comment that was left unterminated flag = TRUE; /* next comment: hey, where did this line go? */ (180) unterminated comment in included file (Preprocessor) Comments begun inside an included file must end inside the included file. (181) non-scalar types can’t be converted to other types (Parser) You can’t convert a structure, union or array to another type, e.g.: struct TEST test; struct TEST * sp; sp = test; /* oops -- did you mean: sp = &test; ? */ (182) illegal conversion between types (Parser) This expression implies a conversion between incompatible types, e.g. a conversion of a structure type into an integer, e.g.: struct LAYOUT layout; int i; layout = i; /* int cannot be converted to struct */ Note that even if a structure only contains an int , for example, it cannot be assigned to an int variable, and vice versa. (183) function or function pointer required (Parser) Only a function or function pointer can be the subject of a function call, e.g.: int a, b, c, d; a = b(c+d); /* b is not a function -- did you mean a = b*(c+d) ? */  2010 Microchip Technology Inc. DS51865B-page 251 (184) calling an interrupt function is illegal (Parser) A function qualified interrupt can’t be called from other functions. It can only be called by a hardware (or software) interrupt. This is because an interrupt function has special function entry and exit code that is appropriate only for calling from an interrupt. An interrupt function can call other non-interrupt functions. (185) function does not take arguments (Parser, Code Generator) This function has no parameters, but it is called here with one or more arguments, e.g.: int get_value(void); void main(void) { int input; input = get_value(6); /* oops -- parameter should not be here */ } (186) too many function arguments (Parser) This function does not accept as many arguments as there are here. void add(int a, int b); add(5, 7, input); /* call has too many arguments */ (187) too few function arguments (Parser) This function requires more arguments than are provided in this call, e.g.: void add(int a, int b); add(5); /* this call needs more arguments */ (188) constant expression required (Parser) In this context an expression is required that can be evaluated to a constant at compile time, e.g.: int a; switch(input) { case a: /* oops! can’t use variable as part of a case label */ input++; } (189) illegal type for array dimension (Parser) An array dimension must be either an integral type or an enumerated value. int array[12.5]; /* oops -- twelve and a half elements, eh? */ (190) illegal type for index expression (Parser) An index expression must be either integral or an enumerated value, e.g.: int i, array[10]; i = array[3.5]; /* oops -- exactly which element do you mean? */ (191) cast type must be scalar or void (Parser) A typecast (an abstract type declarator enclosed in parentheses) must denote a type which is either scalar (i.e. not an array or a structure) or the type void , e.g.: lip = (long [])input; /* oops -- maybe: lip = (long *)input */ HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 252  2010 Microchip Technology Inc. (192) undefined identifier "*" (Parser) This symbol has been used in the program, but has not been defined or declared. Check for spelling errors if you think it has been defined. (193) not a variable identifier "*" (Parser) This identifier is not a variable; it may be some other kind of object, e.g. a label. (194) ")" expected (Parser) A closing parenthesis , ) , was expected here. This may indicate you have left out this character in an expression, or you have some other syntax error. The error is flagged on the line at which the code first starts to make no sense. This may be a statement following the incomplete expression, e.g.: if(a == b /* the closing parenthesis is missing here */ b = 0; /* the error is flagged here */ (195) expression syntax (Parser) This expression is badly formed and cannot be parsed by the compiler, e.g.: a /=% b; /* oops -- maybe that should be: a /= b; */ (196) struct/union required (Parser) A structure or union identifier is required before a dot "." , e.g.: int a; a.b = 9; /* oops -- a is not a structure */ (197) struct/union member expected (Parser) A structure or union member name must follow a dot "." or arrow ("->"). (198) undefined struct/union "*" (Parser) The specified structure or union tag is undefined, e.g. struct WHAT what; /* a definition for WHAT was never seen */ (199) logical type required (Parser) The expression used as an operand to if , while statements or to boolean operators like ! and && must be a scalar integral type, e.g.: struct FORMAT format; if(format) /* this operand must be a scaler type */ format.a = 0; (200) taking the address of a register variable is illegal (Parser) A variable declared register may not have storage allocated for it in memory, and thus it is illegal to attempt to take the address of it by applying the & operator, e.g.: int * proc(register int in) { int * ip = ∈ /* oops -- in may not have an address to take */ return ip; } (201) taking the address of this object is illegal (Parser) The expression which was the operand of the & operator is not one that denotes memory storage (“an lvalue”) and therefore its address can not be defined, e.g.:  2010 Microchip Technology Inc. DS51865B-page 253 ip = &8; /* oops -- you can’t take the address of a literal */ (202) only lvalues may be assigned to or modified (Parser) Only an lvalue (i.e. an identifier or expression directly denoting addressable storage) can be assigned to or otherwise modified, e.g.: int array[10]; int * ip; char c; array = ip; /* array isn’t a variable, it can’t be written to */ A typecast does not yield an lvalue, e.g.: /* the contents of c cast to int is only a intermediate value */ (int)c = 1; However you can write this using pointers: *(int *)&c = 1 (203) illegal operation on bit variable (Parser) Not all operations on bit variables are supported. This operation is one of those, e.g.: bit b; int * ip; ip = &b; /* oops -- cannot take the address of a bit object */ (204) void function can’t return a value (Parser) A void function cannot return a value. Any return statement should not be followed by an expression, e.g.: void run(void) { step(); return 1; /* either run should not be void, or remove the 1 */ } (205) integral type required (Parser) This operator requires operands that are of integral type only. (206) illegal use of void expression (Parser) A void expression has no value and therefore you can’t use it anywhere an expression with a value is required, e.g. as an operand to an arithmetic operator. (207) simple type required for "*" (Parser) A simple type (i.e. not an array or structure) is required as an operand to this operator. (208) operands of "*" not same type (Parser) The operands of this operator are of different pointer, e.g.: int * ip; char * cp, * cp2; cp = flag ? ip : cp2; /* result of ? : will be int * or char * */ Maybe you meant something like: cp = flag ? (char *)ip : cp2; HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 254  2010 Microchip Technology Inc. (209) type conflict (Parser) The operands of this operator are of incompatible types. (210) bad size list (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (211) taking sizeof bit is illegal (Parser) It is illegal to use the sizeof operator with the HI-TECH C bit type. When used against a type the sizeof operator gives the number of bytes required to store an object that type. Therefore its usage with the bit type make no sense and is an illegal operation. (212) missing number after pragma "pack" (Parser) The pragma pack requires a decimal number as argument. This specifies the alignment of each member within the structure. Use this with caution as some processors enforce alignment and will not operate correctly if word fetches are made on odd boundaries, e.g.: #pragma pack /* what is the alignment value */ Maybe you meant something like: #pragma pack 2 (214) missing number after pragma "interrupt_level" (Parser) The pragma interrupt_level requires an argument from 0 to 7. (215) missing argument to pragma "switch" (Parser) The pragma switch requires an argument of auto , direct or simple , e.g.: #pragma switch /* oops -- this requires a switch mode */ maybe you meant something like: #pragma switch simple (216) missing argument to pragma "psect" (Parser) The pragma psect requires an argument of the form oldname = newname where oldname is an existing psect name known to the compiler, and newname is the desired new name, e.g.: #pragma psect /* oops -- this requires an psect to redirect */ maybe you meant something like: #pragma psect text=specialtext (218) missing name after pragma "inline" (Parser) The inline pragma expects the name of a function to follow. The function name must be recognized by the code generator for it to be expanded; other functions are not altered, e.g.: #pragma inline /* what is the function name? */ maybe you meant something like: #pragma inline memcpy  2010 Microchip Technology Inc. DS51865B-page 255 (219) missing name after pragma "printf_check" (Parser) The printf_check pragma expects the name of a function to follow. This specifies printf-style format string checking for the function, e.g. #pragma printf_check /* what function is to be checked? */ Maybe you meant something like: #pragma printf_check sprintf Pragmas for all the standard printf-like function are already contained in . (220) exponent expected (Parser) A floating point constant must have at least one digit after the e or E., e.g.: float f; f = 1.234e; /* oops -- what is the exponent? */ (221) hexadecimal digit expected (Parser) After 0x should follow at least one of the HEX digits 0-9 and A-F or a-f , e.g.: a = 0xg6; /* oops -- was that meant to be a = 0xf6 ? */ (222) binary digit expected (Parser) A binary digit was expected following the 0b format specifier, e.g. i = 0bf000; /* oops -- f000 is not a base two value */ (223) digit out of range (Parser, Assembler) A digit in this number is out of range of the radix for the number, e.g. using the digit 8 in an octal number, or HEX digits A-F in a decimal number. An octal number is denoted by the digit string commencing with a zero, while a HEX number starts with "0X" or "0x". For example: int a = 058; /* leading 0 implies octal which has digits 0 - 7 */ (224) illegal "#" directive (Parser) An illegal # preprocessor has been detected. Likely a directive has been misspelt in your code somewhere. (225) missing character in character constant (Parser) The character inside the single quotes is missing, e.g.: char c = ”; /* the character value of what? */ (226) char const too long (Parser) A character constant enclosed in single quotes may not contain more than one character, e.g.: c = ’12’; /* oops -- only one character may be specified */ (227) "." expected after ".." (Parser) The only context in which two successive dots may appear is as part of the ellipsis symbol, which must have 3 dots. (An ellipsis is used in function prototypes to indicate a variable number of parameters.) Either .. was meant to be an ellipsis symbol which would require you to add an extra dot, or it was meant to be a structure member operator which would require you remove one dot. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 256  2010 Microchip Technology Inc. (228) illegal character (*) (Parser) This character is illegal in the C code. Valid characters are the letters, digits and those comprising the acceptable operators, e.g.: c = a; /* oops -- did you mean c = ’a’; ? */ (229) unknown qualifier "*" given to -A (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (230) missing argument to -A (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (231) unknown qualifier "*" given to -I (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (232) missing argument to -I (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (233) bad -Q option "*" (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (234) close error (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (236) simple integer expression required (Parser) A simple integral expression is required after the operator @ , used to associate an absolute address with a variable, e.g.: int address; char LOCK @ address; (237) function "*" redefined (Parser) More than one definition for a function has been encountered in this module. Function overloading is illegal, e.g.: int twice(int a) { return a*2; } /* only one prototype & definition of rv can exist */ long twice(long a) { return a*2; } (238) illegal initialization (Parser) You can’t initialize a typedef declaration, because it does not reserve any storage that can be initialized, e.g.:  2010 Microchip Technology Inc. DS51865B-page 257 /* oops -- uint is a type, not a variable */ typedef unsigned int uint = 99; (239) identifier "*" redefined (from line *) (Parser) This identifier has already been defined in the same scope. It cannot be defined again, e.g.: int a; /* a filescope variable called “a” */ int a; /* attempting to define another of the same name */ Note that variables with the same name, but defined with different scopes are legal, but not recommended. (240) too many initializers (Parser) There are too many initializers for this object. Check the number of initializers against the object definition (array or structure), e.g.: /* three elements, but four initializers */ int ivals[3] = { 2, 4, 6, 8}; (241) initialization syntax (Parser) The initialization of this object is syntactically incorrect. Check for the correct placement and number of braces and commas, e.g.: int iarray[10] = {{’a’, ’b’, ’c’}; /* oops -- one two many {s */ (242) illegal type for switch expression (Parser) A switch operation must have an expression that is either an integral type or an enumerated value, e.g: double d; switch(d) { /* oops -- this must be integral */ case ’1.0’: d = 0; } (243) inappropriate break/continue (Parser) A break or continue statement has been found that is not enclosed in an appropriate control structure. A continue can only be used inside a while , for or do while loop, while break can only be used inside those loops or a switch statement, e.g.: switch(input) { case 0: if(output == 0) input = 0xff; } /* oops! this shouldn’t be here and closed the switch */ break; /* this should be inside the switch */ (244) "default" case redefined (Parser) There is only allowed to be one default label in a switch statement. You have more than one, e.g.: switch(a) { default: /* if this is the default case... */ b = 9; break; default: /* then what is this? */ b = 10; break; HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 258  2010 Microchip Technology Inc. (245) "default" case not in switch (Parser) A label has been encountered called default but it is not enclosed by a switch statement. A default label is only legal inside the body of a switch statement. If there is a switch statement before this default label, there may be one too many closing braces in the switch code which would prematurely terminate the switch statement. See message 246. (246) case label not in switch (Parser) A case label has been encountered, but there is no enclosing switch statement. A case label may only appear inside the body of a switch statement. If there is a switch statement before this case label, there may be one too many closing braces in the switch code which would prematurely terminate the switch statement, e.g.: switch(input) { case ’0’: count++; break; case ’1’: if(count>MAX) count= 0; } /* oops -- this shouldn’t be here */ break; case ’2’: /* error flagged here */ (247) duplicate label "*" (Parser) The same name is used for a label more than once in this function. Note that the scope of labels is the entire function, not just the block that encloses a label, e.g.: start: if(a > 256) goto end; start: /* error flagged here */ if(a == 0) goto start; /* which start label do I jump to? */ (248) inappropriate "else" (Parser) An else keyword has been encountered that cannot be associated with an if statement. This may mean there is a missing brace or other syntactic error, e.g.: /* here is a comment which I have forgotten to close... if(a > b) { c = 0; /* ... that will be closed here, thus removing the “if” */ else /* my “if” has been lost */ c = 0xff; (249) probable missing "}" in previous block (Parser) The compiler has encountered what looks like a function or other declaration, but the preceding function has not been ended with a closing brace. This probably means that a closing brace has been omitted from somewhere in the previous function, although it may well not be the last one, e.g.: void set(char a) { PORTA = a; /* the closing brace was left out here */ void clear(void) /* error flagged here */  2010 Microchip Technology Inc. DS51865B-page 259 { PORTA = 0; } (251) array dimension redeclared (Parser) An array dimension has been declared as a different non-zero value from its previous declaration. It is acceptable to redeclare the size of an array that was previously declared with a zero dimension, but not otherwise, e.g.: extern int array[5]; int array[10]; /* oops -- has it 5 or 10 elements? */ (252) argument * conflicts with prototype (Parser) The argument specified (argument 0 is the left most argument) of this function definition does not agree with a previous prototype for this function, e.g.: /* this is supposedly calc’s prototype */ extern int calc(int, int); int calc(int a, long int b) /* hmmm -- which is right? */ { /* error flagged here */ return sin(b/a); } (253) argument list conflicts with prototype (Parser) The argument list in a function definition is not the same as a previous prototype for that function. Check that the number and types of the arguments are all the same. extern int calc(int); /* this is supposedly calc’s prototype */ int calc(int a, int b) /* hmmm -- which is right? */ { /* error flagged here */ return a + b; } (254) undefined *: "*" (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (255) not a member of the struct/union "*" (Parser) This identifier is not a member of the structure or union type with which it used here, e.g.: struct { int a, b, c; } data; if(data.d) /* oops -- there is no member d in this structure */ return; (256) too much indirection (Parser) A pointer declaration may only have 16 levels of indirection. (257) only "register" storage class allowed (Parser) The only storage class allowed for a function parameter is register , e.g.: void process(static int input) HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 260  2010 Microchip Technology Inc. (258) duplicate qualifier (Parser) There are two occurrences of the same qualifier in this type specification. This can occur either directly or through the use of a typedef. Remove the redundant qualifier. For example: typedef volatile int vint; /* oops -- this results in two volatile qualifiers */ volatile vint very_vol; (259) can’t be qualified both far and near (Parser) It is illegal to qualify a type as both far and near , e.g.: far near int spooky; /* oops -- choose far or near, not both */ (260) undefined enum tag "*" (Parser) This enum tag has not been defined, e.g.: enum WHAT what; /* a definition for WHAT was never seen */ (261) struct/union member "*" redefined (Parser) This name of this member of the struct or union has already been used in this struct or union , e.g.: struct { int a; int b; int a; /* oops -- a different name is required here */ } input; (262) struct/union "*" redefined (Parser) A structure or union has been defined more than once, e.g.: struct { int a; } ms; struct { int a; } ms; /* was this meant to be the same name as above? */ (263) members can’t be functions (Parser) A member of a structure or a union may not be a function. It may be a pointer to a function, e.g.: struct { int a; int get(int); /* should be a pointer: int (*get)(int); */ } object; (264) bad bitfield type (Parser) A bitfield may only have a type of int (signed or unsigned ), e.g.: struct FREG { char b0:1; /* these must be part of an int, not char */ char :6; char b7:1; } freg;  2010 Microchip Technology Inc. DS51865B-page 261 (265) integer constant expected (Parser) A colon appearing after a member name in a structure declaration indicates that the member is a bitfield. An integral constant must appear after the colon to define the number of bits in the bitfield, e.g.: struct { unsigned first: /* oops -- should be: unsigned first; */ unsigned second; } my_struct; If this was meant to be a structure with bitfields, then the following illustrates an exam- ple: struct { unsigned first : 4; /* 4 bits wide */ unsigned second: 4; /* another 4 bits */ } my_struct; (266) storage class illegal (Parser) A structure or union member may not be given a storage class. Its storage class is determined by the storage class of the structure, e.g.: struct { /* no additional qualifiers may be present with members */ static int first; } ; (267) bad storage class (Code Generator) The code generator has encountered a variable definition whose storage class is invalid, e.g.: auto int foo; /* auto not permitted with global variables */ int power(static int a) /* parameters may not be static */ { return foo * a; } (268) inconsistent storage class (Parser) A declaration has conflicting storage classes. Only one storage class should appear in a declaration, e.g.: extern static int where; /* so is it static or extern? */ (269) inconsistent type (Parser) Only one basic type may appear in a declaration, e.g.: int float if; /* is it int or float? */ (270) variable can’t have storage class "register" (Parser) Only function parameters or auto variables may be declared using the register qualifier, e.g.: register int gi; /* this cannot be qualified register */ int process(register int input) /* this is okay */ { return input + gi; } (271) type can’t be long (Parser) Only int and float can be qualified with long. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 262  2010 Microchip Technology Inc. long char lc; /* what? */ (272) type can’t be short (Parser) Only int can be modified with short , e.g.: short float sf; /* what? */ (273) type can’t be both signed and unsigned (Parser) The type modifiers signed and unsigned cannot be used together in the same declaration, as they have opposite meaning, e.g.: signed unsigned int confused; /* which is it? */ (274) type can’t be unsigned (Parser) A floating point type cannot be made unsigned , e.g.: unsigned float uf; /* what? */ (275) "..." illegal in non-prototype argument list (Parser) The ellipsis symbol may only appear as the last item in a prototyped argument list. It may not appear on its own, nor may it appear after argument names that do not have types, i.e. K&R-style non-prototype function definitions. For example: /* K&R-style non-prototyped function definition */ int kandr(a, b, ...) int a, b; { (276) type specifier required for prototyped argument (Parser) A type specifier is required for a prototyped argument. It is not acceptable to just have an identifier. (277) can’t mix prototyped and non-prototyped arguments (Parser) A function declaration can only have all prototyped arguments (i.e. with types inside the parentheses) or all K&R style args (i.e. only names inside the parentheses and the argument types in a declaration list before the start of the function body), e.g.: int plus(int a, b) /* oops -- a is prototyped, b is not */ int b; { return a + b; } (278) argument "*" redeclared (Parser) The specified argument is declared more than once in the same argument list, e.g. /* can’t have two parameters called “a” */ int calc(int a, int a) (279) initialization of function arguments is illegal (Parser) A function argument can’t have an initializer in a declaration. The initialization of the argument happens when the function is called and a value is provided for the argument by the calling function, e.g.: /* oops -- a is initialized when proc is called */ extern int proc(int a = 9);  2010 Microchip Technology Inc. DS51865B-page 263 (280) arrays of functions are illegal (Parser) You can’t define an array of functions. You can however define an array of pointers to functions, e.g.: int * farray[](); /* oops -- should be: int (* farray[])(); */ (281) functions can’t return functions (Parser) A function cannot return a function. It can return a function pointer. A function returning a pointer to a function could be declared like this: int (* (name()))(). Note the many parentheses that are necessary to make the parts of the declaration bind correctly. (282) functions can’t return arrays (Parser) A function can return only a scalar (simple) type or a structure. It cannot return an array. (283) dimension required (Parser) Only the most significant (i.e. the first) dimension in a multi-dimension array may not be assigned a value. All succeeding dimensions must be present as a constant expression, e.g.: /* This should be, e.g.: int arr[][7] */ int get_element(int arr[2][]) { return array[1][6]; } (284) invalid dimension (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (285) no identifier in declaration (Parser) The identifier is missing in this declaration. This error can also occur where the compiler has been confused by such things as missing closing braces, e.g.: void interrupt(void) /* what is the name of this function? */ { } (286) declarator too complex (Parser) This declarator is too complex for the compiler to handle. Examine the declaration and find a way to simplify it. If the compiler finds it too complex, so will anybody maintaining the code. (287) arrays of bits or pointers to bit are illegal (Parser) It is not legal to have an array of bits, or a pointer to bit variable, e.g.: bit barray[10]; /* wrong -- no bit arrays */ bit * bp; /* wrong -- no pointers to bit variables */ (288) only functions may be void (Parser) A variable may not be void. Only a function can be void , e.g.: int a; void b; /* this makes no sense */ (289) only functions may be qualified "interrupt" (Parser) The qualifier interrupt may not be applied to anything except a function, e.g.: HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 264  2010 Microchip Technology Inc. /* variables cannot be qualified interrupt */ interrupt int input; (290) illegal function qualifier(s) (Parser) A qualifier has been applied to a function which makes no sense in this context. Some qualifier only make sense when used with an lvalue, e.g. const or volatile. This may indicate that you have forgotten out a star * indicating that the function should return a pointer to a qualified object, e.g. const char ccrv(void) /* const * char ccrv(void) perhaps? */ { /* error flagged here */ return ccip; } (291) K&R identifier "*" not an argument (Parser) This identifier that has appeared in a K&R style argument declarator is not listed inside the parentheses after the function name, e.g.: int process(input) int unput; /* oops -- that should be int input; */ { } (292) function parameter may not be a function (Parser) A function parameter may not be a function. It may be a pointer to a function, so perhaps a "*" has been omitted from the declaration. (293) bad size in index_type() (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (294) can’t allocate * bytes of memory (Code Generator, Hexmate) This is an internal compiler error. Contact HI-TECH Software technical support with details. (295) expression too complex (Parser) This expression has caused overflow of the compiler’s internal stack and should be re-arranged or split into two expressions. (296) out of memory (Objtohex) This could be an internal compiler error. Contact HI-TECH Software technical support with details. (297) bad argument (*) to tysize() (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (298) end of file in #asm (Preprocessor) An end of file has been encountered inside a #asm block. This probably means the #endasm is missing or misspelt, e.g.: #asm MOV r0, #55 MOV [r1], r0 } /* oops -- where is the #endasm */  2010 Microchip Technology Inc. DS51865B-page 265 (300) unexpected end of file (Parser) An end-of-file in a C module was encountered unexpectedly, e.g.: void main(void) { init(); run(); /* is that it? What about the close brace */ (301) end of file on string file (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (302) can’t reopen "*": * (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (303) can’t allocate * bytes of memory (line *) (Parser) The parser was unable to allocate memory for the longest string encountered, as it attempts to sort and merge strings. Try reducing the number or length of strings in this module. (306) can’t allocate * bytes of memory for * (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (307) too many qualifier names (Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (308) too many case labels in switch (Code Generator) There are too many case labels in this switch statement. The maximum allowable number of case labels in any one switch statement is 511. (309) too many symbols (Assembler) There are too many symbols for the assembler’s symbol table. Reduce the number of symbols in your program. (310) "]" expected (Parser) A closing square bracket was expected in an array declaration or an expression using an array index, e.g. process(carray[idx); /* oops -- should be: process(carray[idx]); */ (311) closing quote expected (Parser) A closing quote was expected for the indicated string. (312) "*" expected (Parser) The indicated token was expected by the parser. (313) function body expected (Parser) Where a function declaration is encountered with K&R style arguments (i.e. argument names but no types inside the parentheses) a function body is expected to follow, e.g.: HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 266  2010 Microchip Technology Inc. /* the function block must follow, not a semicolon */ int get_value(a, b); (314) ";" expected (Parser) A semicolon is missing from a statement. A close brace or keyword was found following a statement with no terminating semicolon , e.g.: while(a) { b = a-- /* oops -- where is the semicolon? */ } /* error is flagged here */ Note: Omitting a semicolon from statements not preceding a close brace or keyword typically results in some other error being issued for the following code which the parser assumes to be part of the original statement. (315) "{" expected (Parser) An opening brace was expected here. This error may be the result of a function definition missing the opening brace , e.g.: /* oops! no opening brace after the prototype */ void process(char c) return max(c, 10) * 2; /* error flagged here */ } (316) "}" expected (Parser) A closing brace was expected here. This error may be the result of a initialized array missing the closing brace , e.g.: char carray[4] = { 1, 2, 3, 4; /* oops -- no closing brace */ (317) "(" expected (Parser) An opening parenthesis , ( , was expected here. This must be the first token after a while , for , if , do or asm keyword, e.g.: if a == b /* should be: if(a == b) */ b = 0; (318) string expected (Parser) The operand to an asm statement must be a string enclosed in parentheses, e.g.: asm(nop); /* that should be asm(“nop”); (319) while expected (Parser) The keyword while is expected at the end of a do statement, e.g.: do { func(i++); } /* do the block while what condition is true? */ if(i > 5) /* error flagged here */ end(); (320) ":" expected (Parser) A colon is missing after a case label, or after the keyword default. This often occurs when a semicolon is accidentally typed instead of a colon , e.g.: switch(input) { case 0; /* oops -- that should have been: case 0: */ state = NEW;  2010 Microchip Technology Inc. DS51865B-page 267 (321) label identifier expected (Parser) An identifier denoting a label must appear after goto , e.g.: if(a) goto 20; /* this is not BASIC -- a valid C label must follow a goto */ (322) enum tag or "{" expected (Parser) After the keyword enum must come either an identifier that is or will be defined as an enum tag, or an opening brace, e.g.: enum 1, 2; /* should be, e.g.: enum {one=1, two }; */ (323) struct/union tag or "{" expected (Parser) An identifier denoting a structure or union or an opening brace must follow a struct or union keyword, e.g.: struct int a; /* this is not how you define a structure */ You might mean something like: struct { int a; } my_struct; (324) too many arguments for printf-style format string (Parser) There are too many arguments for this format string. This is harmless, but may represent an incorrect format string, e.g.: /* oops -- missed a placeholder? */ printf(“%d - %d”, low, high, median); (325) error in printf-style format string (Parser) There is an error in the format string here. The string has been interpreted as a printf() style format string, and it is not syntactically correct. If not corrected, this will cause unexpected behavior at run time, e.g.: printf(“%l”, lll); /* oops -- maybe: printf(“%ld”, lll); */ (326) long int argument required in printf-style format string (Parser) A long argument is required for this format specifier. Check the number and order of format specifiers and corresponding arguments, e.g.: printf(“%lx”, 2); // maybe you meant: printf(“%lx”, 2L); (327) long long int argument required in printf-style format string (Parser) A long long argument is required for this format specifier. Check the number and order of format specifiers and corresponding arguments, e.g.: printf(“%llx”, 2); // maybe you meant: printf(“%llx”, 2LL); Note that not all HI-TECH C compilers provide support for a long long integer type. (328) int argument required in printf-style format string (Parser) An integral argument is required for this printf-style format specifier. Check the number and order of format specifiers and corresponding arguments, e.g.: printf(“%d”, 1.23); /* wrong number or wrong placeholder */ HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 268  2010 Microchip Technology Inc. (329) double argument required in printf-style format string (Parser) The printf format specifier corresponding to this argument is %f or similar, and requires a floating point expression. Check for missing or extra format specifiers or arguments to printf. printf(“%f”, 44); /* should be: printf(“%f”, 44.0); */ (330) pointer to * argument required in printf-style format string (Parser) A pointer argument is required for this format specifier. Check the number and order of format specifiers and corresponding arguments. (331) too few arguments for printf-style format string (Parser) There are too few arguments for this format string. This would result in a garbage value being printed or converted at run time, e.g.: printf(“%d - %d”, low); /* oops! where is the other value to print? */ (332) "interrupt_level" should be 0 to 7 (Parser) The pragma interrupt_level must have an argument from 0 to 7, e.g.: #pragma interrupt_level /* oops -- what is the level */ void interrupt isr(void) { /* isr code goes here */ } (333) unrecognized qualifier name after "strings" (Parser) The pragma strings was passed a qualifier that was not identified, e.g.: /* oops -- should that be #pragma strings const ? */ #pragma strings cinst (334) unrecognized qualifier name after "printf_check" (Parser) The #pragma printf_check was passed a qualifier that could not be identified, e.g.: /* oops -- should that be const not cinst? */ #pragma printf_check(printf) cinst (335) unknown pragma "*" (Parser) An unknown pragma directive was encountered, e.g.: #pragma rugsused w /* I think you meant regsused */ (336) string concatenation across lines (Parser) Strings on two lines will be concatenated. Check that this is the desired result, e.g.: char * cp = “hi” “there”; /* this is okay, but is it what you had intended? */ (337) line does not have a newline on the end (Parser) The last line in the file is missing the newline (operating system dependent character) from the end. Some editors will create such files, which can cause problems for include files. The ANSI C standard requires all source files to consist of complete lines only.  2010 Microchip Technology Inc. DS51865B-page 269 (338) can’t create * file "*" (Any) The application tried to create or open the named file, but it could not be created. Check that all file path names are correct. (339) initializer in extern declaration (Parser) A declaration containing the keyword extern has an initializer. This overrides the extern storage class, since to initialise an object it is necessary to define (i.e. allocate storage for) it, e.g.: extern int other = 99; /* if it’s extern and not allocated storage, how can it be initialized? */ (340) string not terminated by null character. (Parser) A char array is being initialized with a string literal larger than the array. Hence there is insufficient space in the array to safely append a null terminating character, e.g.: char foo[5] = “12345”; /* the string stored in foo won’t have a null terminating, i.e. foo = [’1’, ’2’, ’3’, ’4’, ’5’] */ (343) implicit return at end of non-void function (Parser) A function which has been declared to return a value has an execution path that will allow it to reach the end of the function body, thus returning without a value. Either insert a return statement with a value, or if the function is not to return a value, declare it void , e.g.: int mydiv(double a, int b) { if(b != 0) return a/b; /* what about when b is 0? */ } /* warning flagged here */ (344) non-void function returns no value (Parser) A function that is declared as returning a value has a return statement that does not specify a return value, e.g.: int get_value(void) { if(flag) return val++; return; /* what is the return value in this instance? */ } (345) unreachable code (Parser) This section of code will never be executed, because there is no execution path by which it could be reached, e.g.: while(1) /* how does this loop finish? */ process(); flag = FINISHED; /* how do we get here? */ (346) declaration of "*" hides outer declaration (Parser) An object has been declared that has the same name as an outer declaration (i.e. one outside and preceding the current function or block). This is legal, but can lead to accidental use of one variable when the outer one was intended, e.g.: int input; /* input has filescope */ HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 270  2010 Microchip Technology Inc. void process(int a) { int input; /* local blockscope input */ a = input; /* this will use the local variable. Is this right? */ (347) external declaration inside function (Parser) A function contains an extern declaration. This is legal but is invariably not desirable as it restricts the scope of the function declaration to the function body. This means that if the compiler encounters another declaration, use or definition of the extern object later in the same file, it will no longer have the earlier declaration and thus will be unable to check that the declarations are consistent. This can lead to strange behavior of your program or signature errors at link time. It will also hide any previous declarations of the same thing, again subverting the compiler’s type checking. As a general rule, always declare extern variables and functions outside any other functions. For exam- ple: int process(int a) { /* this would be better outside the function */ extern int away; return away + a; } (348) auto variable "*" should not be qualified (Parser) An auto variable should not have qualifiers such as near or far associated with it. Its storage class is implicitly defined by the stack organization. An auto variable may be qualified with static , but it is then no longer auto. (349) non-prototyped function declaration for "*" (Parser) A function has been declared using old-style (K&R) arguments. It is preferable to use prototype declarations for all functions, e.g.: int process(input) int input; /* warning flagged here */ { } This would be better written: int process(int input) { } (350) unused * "*" (from line *) (Parser) The indicated object was never used in the function or module being compiled. Either this object is redundant, or the code that was meant to use it was excluded from compilation or misspelt the name of the object. Note that the symbols rcsid and sccsid are never reported as being unused. (352) float parameter coerced to double (Parser) Where a non-prototyped function has a parameter declared as float , the compiler converts this into a double float. This is because the default C type conversion conventions provide that when a floating point number is passed to a non-prototyped function, it will be converted to double. It is important that the function declaration be consistent with this convention, e.g.: double inc_flt(f) /* f will be converted to double */ float f; /* warning flagged here */  2010 Microchip Technology Inc. DS51865B-page 271 { return f * 2; } (353) sizeof external array "*" is zero (Parser) The size of an external array evaluates to zero. This is probably due to the array not having an explicit dimension in the extern declaration. (354) possible pointer truncation (Parser) A pointer qualified far has been assigned to a default pointer or a pointer qualified near, or a default pointer has been assigned to a pointer qualified near. This may result in truncation of the pointer and loss of information, depending on the memory model in use. (355) implicit signed to unsigned conversion (Parser) A signed number is being assigned or otherwise converted to a larger unsigned type. Under the ANSI C “value preserving” rules, this will result in the signed value being first sign-extended to a signed number the size of the target type, then converted to unsigned (which involves no change in bit pattern). Thus an unexpected sign extension can occur. To ensure this does not happen, first convert the signed value to an unsigned equivalent, e.g.: signed char sc; unsigned int ui; ui = sc; /* if sc contains 0xff, ui will contain 0xffff for example */ will perform a sign extension of the char variable to the longer type. If you do not want this to take place, use a cast, e.g.: ui = (unsigned char)sc; (356) implicit conversion of float to integer (Parser) A floating point value has been assigned or otherwise converted to an integral type. This could result in truncation of the floating point value. A typecast will make this warning go away. double dd; int i; i = dd; /* is this really what you meant? */ If you do intend to use an expression like this, then indicate that this is so by a cast: i = (int)dd; (357) illegal conversion of integer to pointer (Parser) An integer has been assigned to or otherwise converted to a pointer type. This will usually mean you have used the wrong variable, but if this is genuinely what you want to do, use a typecast to inform the compiler that you want the conversion and the warning will be suppressed. This may also mean you have forgotten the & address operator, e.g.: int * ip; int i; ip = i; /* oops -- did you mean ip = &i ? */ If you do intend to use an expression like this, then indicate that this is so by a cast: ip = (int *)i; HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 272  2010 Microchip Technology Inc. (358) illegal conversion of pointer to integer (Parser) A pointer has been assigned to or otherwise converted to a integral type. This will usually mean you have used the wrong variable, but if this is genuinely what you want to do, use a typecast to inform the compiler that you want the conversion and the warning will be suppressed. This may also mean you have forgotten the * dereference operator, e.g.: int * ip; int i; i = ip; /* oops -- did you mean i = *ip ? */ If you do intend to use an expression like this, then indicate that this is so by a cast: i = (int)ip; (359) illegal conversion between pointer types (Parser) A pointer of one type (i.e. pointing to a particular kind of object) has been converted into a pointer of a different type. This will usually mean you have used the wrong variable, but if this is genuinely what you want to do, use a typecast to inform the compiler that you want the conversion and the warning will be suppressed, e.g.: long input; char * cp; cp = &input; /* is this correct? */ This is common way of accessing bytes within a multi-byte variable. To indicate that this is the intended operation of the program, use a cast: cp = (char *)&input; /* that’s better */ This warning may also occur when converting between pointers to objects which have the same type, but which have different qualifiers, e.g.: char * cp; /* yes, but what sort of characters? */ cp = “I am a string of characters”; If the default type for string literals is const char * , then this warning is quite valid. This should be written: const char * cp; cp = “I am a string of characters”; /* that’s better */ Omitting a qualifier from a pointer type is often disastrous, but almost certainly not what you intend. (360) array index out of bounds (Parser) An array is being indexed with a constant value that is less than zero, or greater than or equal to the number of elements in the array. This warning will not be issued when accessing an array element via a pointer variable, e.g.: int i, * ip, input[10]; i = input[-2]; /* oops -- this element doesn’t exist */ ip = &input[5]; i = ip[-2]; /* this is okay */ (361) function declared implicit int (Parser) Where the compiler encounters a function call of a function whose name is presently undefined, the compiler will automatically declare the function to be of type int , with unspecified (K&R style) parameters. If a definition of the function is subsequently encountered, it is possible that its type and arguments will be different from the earlier implicit declaration, causing a compiler error. The solution is to ensure that all functions  2010 Microchip Technology Inc. DS51865B-page 273 are defined or at least declared before use, preferably with prototyped parameters. If it is necessary to make a forward declaration of a function, it should be preceded with the keywords extern or static as appropriate. For example: /* I may prevent an error arising from calls below */ void set(long a, int b); void main(void) { /* by here a prototype for set should have seen */ set(10L, 6); } (362) redundant "&" applied to array (Parser) The address operator & has been applied to an array. Since using the name of an array gives its address anyway, this is unnecessary and has been ignored, e.g.: int array[5]; int * ip; /* array is a constant, not a variable; the & is redundant. */ ip = &array; (363) redundant "&" or "*" applied to function address (Parser) The address operator "&" has been applied to a function. Since using the name of a function gives its address anyway, this is unnecessary and has been ignored, e.g.: extern void foo(void); void main(void) { void(*bar)(void); /* both assignments are equivalent */ bar = &foo; bar = foo; /* the & is redundant */ } (364) attempt to modify object qualified * (Parser) Objects declared const or code may not be assigned to or modified in any other way by your program. The effect of attempting to modify such an object is compiler-specific. const int out = 1234; /* “out” is read only */ out = 0; /* oops -- writing to a read-only object */ (365) pointer to non-static object returned (Parser) This function returns a pointer to a non-static (e.g. auto ) variable. This is likely to be an error, since the storage associated with automatic variables becomes invalid when the function returns, e.g.: char * get_addr(void) { char c; /* returning this is dangerous; the pointer could be dereferenced */ return &c; } (366) operands of "*" not same pointer type (Parser) The operands of this operator are of different pointer types. This probably means you have used the wrong pointer, but if the code is actually what you intended, use a typecast to suppress the error message. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 274  2010 Microchip Technology Inc. (367) identifier is already extern; can’t be static (Parser) This function was already declared extern, possibly through an implicit declaration. It has now been redeclared static, but this redeclaration is invalid. void main(void) { /* at this point the compiler assumes set is extern... */ set(10L, 6); } /* now it finds out otherwise */ static void set(long a, int b) { PORTA = a + b; } (368) array dimension on "*[]" ignored (Preprocessor) An array dimension on a function parameter has been ignored because the argument is actually converted to a pointer when passed. Thus arrays of any size may be passed. Either remove the dimension from the parameter, or define the parameter using pointer syntax, e.g.: /* param should be: “int array[]” or “int *” */ int get_first(int array[10]) { /* warning flagged here */ return array[0]; } (369) signed bitfields not supported (Parser) Only unsigned bitfields are supported. If a bitfield is declared to be type int , the compiler still treats it as unsigned , e.g.: struct { signed int sign: 1; /* this must be unsigned */ signed int value: 15; } ; (370) illegal basic type; int assumed (Parser) The basic type of a cast to a qualified basic type couldn’t not be recognized and the basic type was assumed to be int , e.g.: /* here ling is assumed to be int */ unsigned char bar = (unsigned ling) ’a’; (371) missing basic type; int assumed (Parser) This declaration does not include a basic type, so int has been assumed. This declaration is not illegal, but it is preferable to include a basic type to make it clear what is intended, e.g.: char c; i; /* don’t let the compiler make assumptions, use : int i */ func(); /* ditto, use: extern int func(int); */ (372) "," expected (Parser) A comma was expected here. This could mean you have left out the comma between two identifiers in a declaration list. It may also mean that the immediately preceding type name is misspelled, and has thus been interpreted as an identifier, e.g.: unsigned char a; /* thinks: chat & b are unsigned, but where is the comma? */  2010 Microchip Technology Inc. DS51865B-page 275 unsigned chat b; (373) implicit signed to unsigned conversion (Parser) An unsigned type was expected where a signed type was given and was implicitly cast to unsigned , e.g.: unsigned int foo = -1; /* the above initialization is implicitly treated as: unsigned int foo = (unsigned) -1; */ (374) missing basic type; int assumed (Parser) The basic type of a cast to a qualified basic type was missing and assumed to be int., e.g.: int i = (signed) 2; /* (signed) assumed to be (signed int) */ (375) unknown FNREC type "*" (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (376) bad non-zero node in call graph (Linker) The linker has encountered a top level node in the call graph that is referenced from lower down in the call graph. This probably means the program has indirect recursion, which is not allowed when using a compiled stack. (378) can’t create * file "*" (Hexmate) This type of file could not be created. Is the file or a file by this name already in use? (379) bad record type "*" (Linker) This is an internal compiler error. Ensure the object file is a valid HI-TECH object file. Contact HI-TECH Software technical support with details. (380) unknown record type (*) (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (381) record "*" too long (*) (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (382) incomplete record: type = *, length = * (Dump, Xstrip) This message is produced by the DUMP or XSTRIP utilities and indicates that the object file is not a valid HI-TECH object file, or that it has been truncated. Contact HI-TECH Support with details. (383) text record has length (*) too small (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (384) assertion failed: file *, line *, expression * (Linker, Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 276  2010 Microchip Technology Inc. (387) illegal or too many -G options (Linker) There has been more than one linker -g option, or the -g option did not have any arguments following. The arguments specify how the segment addresses are calculated. (388) duplicate -M option (Linker) The map file name has been specified to the linker for a second time. This should not occur if you are using a compiler driver. If invoking the linker manually, ensure that only one instance of this option is present on the command line. See Section 2.7.8 “-M: Generate Map File” for information on the correct syntax for this option. (389) illegal or too many -O options (Linker) This linker -o flag is illegal, or another -o option has been encountered. A -o option to the linker must be immediately followed by a filename with no intervening space. (390) missing argument to -P (Linker) There have been too many -p options passed to the linker, or a -p option was not followed by any arguments. The arguments of separate -p options may be combined and separated by commas. (391) missing argument to -Q (Linker) The -Q linker option requires the machine type for an argument. (392) missing argument to -U (Linker) The -U (undefine) option needs an argument. (393) missing argument to -W (Linker) The -W option (listing width) needs a numeric argument. (394) duplicate -D or -H option (Linker) The symbol file name has been specified to the linker for a second time. This should not occur if you are using a compiler driver. If invoking the linker manually, ensure that only one instance of either of these options is present on the command line. (395) missing argument to -J (Linker) The maximum number of errors before aborting must be specified following the -j linker option. (397) usage: hlink [-options] files.obj files.lib (Linker) Improper usage of the command-line linker. If you are invoking the linker directly then please refer to Section Section 5.2 “Operation” for more details. Otherwise this may be an internal compiler error and you should contact HI-TECH Software technical support with details. (398) output file can’t be also an input file (Linker) The linker has detected an attempt to write its output file over one of its input files. This cannot be done, because it needs to simultaneously read and write input and output files.  2010 Microchip Technology Inc. DS51865B-page 277 (400) bad object code format (Linker) This is an internal compiler error. The object code format of an object file is invalid. Ensure it is a valid HI-TECH object file. Contact HI-TECH Software technical support with details. (402) bad argument to -F (Objtohex) The -F option for objtohex has been supplied an invalid argument. If you are invoking this command-line tool directly then please refer to Section 6.3 “Objtohex” for more details. Otherwise this may be an internal compiler error and you should contact HI-TECH Software technical support with details. (403) bad -E option: "*" (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (404) bad maximum length value to - (Objtohex) The first value to the OBJTOHEX -n,m HEX length/rounding option is invalid. (405) bad record size rounding value to - (Objtohex) The second value to the OBJTOHEX -n,m HEX length/rounding option is invalid. (406) bad argument to -A (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (407) bad argument to -U (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (408) bad argument to -B (Objtohex) This option requires an integer argument in either base 8, 10 or 16. If you are invoking objtohex directly then see Section 6.3 “Objtohex” for more details. Otherwise this may be an internal compiler error and you should contact HI-TECH Software technical support with details. (409) bad argument to -P (Objtohex) This option requires an integer argument in either base 8, 10 or 16. If you are invoking objtohex directly then see Section 6.3 “Objtohex” for more details. Otherwise this may be an internal compiler error and you should contact HI-TECH Software technical support with details. (410) bad combination of options (Objtohex) The combination of options supplied to OBJTOHEX is invalid. (412) text does not start at 0 (Objtohex) Code in some things must start at zero. Here it doesn’t. (413) write error on "*" (Assembler, Linker, Cromwell) A write error occurred on the named file. This probably means you have run out of disk space. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 278  2010 Microchip Technology Inc. (414) read error on "*" (Linker) The linker encountered an error trying to read this file. (415) text offset too low in COFF file (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (416) bad character (*) in extended TEKHEX line (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (417) seek error in "*" (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (418) image too big (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (419) object file is not absolute (Objtohex) The object file passed to OBJTOHEX has relocation items in it. This may indicate it is the wrong object file, or that the linker or OBJTOHEX have been given invalid options. The object output files from the assembler are relocatable, not absolute. The object file output of the linker is absolute. (420) too many relocation items (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (421) too many segments (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (422) no end record (Linker) This object file has no end record. This probably means it is not an object file. Contact HI-TECH Support if the object file was generated by the compiler. (423) illegal record type (Linker) There is an error in an object file. This is either an invalid object file, or an internal error in the linker. Contact HI-TECH Support with details if the object file was created by the compiler. (424) record too long (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (425) incomplete record (Objtohex, Libr) The object file passed to OBJTOHEX or the librarian is corrupted. Contact HI-TECH Support with details.  2010 Microchip Technology Inc. DS51865B-page 279 (427) syntax error in checksum list (Objtohex) There is a syntax error in a checksum list read by OBJTOHEX. The checksum list is read from standard input in response to an option. (428) too many segment fixups (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (429) bad segment fixups (Objtohex) This is an internal compiler error. Contact HI-TECH Software technical support with details. (430) bad checksum specification (Objtohex) A checksum list supplied to OBJTOHEX is syntactically incorrect. (431) bad argument to -E (Objtoexe) This option requires an integer argument in either base 8, 10 or 16. If you are invoking objtoexe directly then check this argument. Otherwise this may be an internal compiler error and you should contact HI-TECH Software technical support with details. (432) usage: objtohex [-ssymfile] [object-file [exe-file]] (Objtohex) Improper usage of the command-line tool objtohex. If you are invoking objtohex directly then please refer to Section 6.3 “Objtohex” for more details. Otherwise this may be an internal compiler error and you should contact HI-TECH Software technical support with details. (434) too many symbols (*) (Linker) There are too many symbols in the symbol table, which has a limit of * symbols. Change some global symbols to local symbols to reduce the number of symbols. (435) bad segment selector "*" (Linker) The segment specification option (-G ) to the linker is invalid, e.g.: -GA/f0+10 Did you forget the radix? -GA/f0h+10 (436) psect "*" re-orged (Linker) This psect has had its start address specified more than once. (437) missing "=" in class spec (Linker) A class spec needs an = sign, e.g. -Ctext=ROM See Section “-Cpsect=class” for more information. (438) bad size in -S option (Linker) The address given in a -S specification is invalid: it should be a valid number, in decimal, octal or hexadecimal radix. The radix is specified by a trailing O , for octal, or H for HEX. A leading 0x may also be used for hexadecimal. Case in not important for any number or radix. Decimal is the default, e.g.: -SCODE=f000 Did you forget the radix? HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 280  2010 Microchip Technology Inc. -SCODE=f000h (439) bad -D spec: "*" (Linker) The format of a -D specification, giving a delta value to a class, is invalid, e.g.: -DCODE What is the delta value for this class? Maybe you meant something like: -DCODE=2 (440) bad delta value in -D spec (Linker) The delta value supplied to a -D specification is invalid. This value should an integer of base 8, 10 or 16. (441) bad -A spec: "*" (Linker) The format of a -A specification, giving address ranges to the linker, is invalid, e.g.: -ACODE What is the range for this class? Maybe you meant: -ACODE=0h-1fffh (442) missing address in -A spec (Linker) The format of a -A specification, giving address ranges to the linker, is invalid, e.g.: -ACODE= What is the range for this class? Maybe you meant: -ACODE=0h-1fffh (443) bad low address "*" in -A spec (Linker) The low address given in a -A specification is invalid: it should be a valid number, in decimal, octal or hexadecimal radix. The radix is specified by a trailing O (for octal) or H for HEX. A leading 0x may also be used for hexadecimal. Case in not important for any number or radix. Decimal is default, e.g.: -ACODE=1fff-3fffh Did you forget the radix? -ACODE=1fffh-3fffh (444) expected "-" in -A spec (Linker) There should be a minus sign, - , between the high and low addresses in a -A linker option, e.g. -AROM=1000h maybe you meant: -AROM=1000h-1fffh (445) bad high address "*" in -A spec (Linker) The high address given in a -A specification is invalid: it should be a valid number, in decimal, octal or hexadecimal radix. The radix is specified by a trailing O , for octal, or H for HEX. A leading 0x may also be used for hexadecimal. Case in not important for any number or radix. Decimal is the default, e.g.: -ACODE=0h-ffff Did you forget the radix? -ACODE=0h-ffffh  2010 Microchip Technology Inc. DS51865B-page 281 See Section 5.2.1 “-Aclass =low-high,...” for more information. (446) bad overrun address "*" in -A spec (Linker) The overrun address given in a -A specification is invalid: it should be a valid number, in decimal, octal or hexadecimal radix. The radix is specified by a trailing O (for octal) or H for HEX. A leading 0x may also be used for hexadecimal. Case in not important for any number or radix. Decimal is default, e.g.: -AENTRY=0-0FFh-1FF Did you forget the radix? -AENTRY=0-0FFh-1FFh (447) bad load address "*" in -A spec (Linker) The load address given in a -A specification is invalid: it should be a valid number, in decimal, octal or hexadecimal radix. The radix is specified by a trailing O (for octal) or H for HEX. A leading 0x may also be used for hexadecimal. Case in not important for any number or radix. Decimal is default, e.g.: -ACODE=0h-3fffh/a000 Did you forget the radix? -ACODE=0h-3fffh/a000h (448) bad repeat count "*" in -A spec (Linker) The repeat count given in a -A specification is invalid, e.g.: -AENTRY=0-0FFhxf Did you forget the radix? -AENTRY=0-0FFhxfh (449) syntax error in -A spec: * (Linker) The -A spec is invalid. A valid -A spec should be something like: -AROM=1000h-1FFFh (450) psect "*" was never defined (Linker) This psect has been listed in a -P option, but is not defined in any module within the program. (451) bad psect origin format in -P option (Linker) The origin format in a -p option is not a validly formed decimal, octal or HEX number, nor is it the name of an existing psect. A HEX number must have a trailing H, e.g.: -pbss=f000 Did you forget the radix? -pbss=f000h (452) bad "+" (minimum address) format in -P option (Linker) The minimum address specification in the linker’s -p option is badly formatted, e.g.: -pbss=data+f000 Did you forget the radix? -pbss=data+f000h HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 282  2010 Microchip Technology Inc. (453) missing number after "%" in -P option (Linker) The % operator in a -p option (for rounding boundaries) must have a number after it. (454) link and load address can’t both be set to "." in -P option (Linker) The link and load address of a psect have both been specified with a dot character. Only one of these addresses may be specified in this manner, e.g.: -Pmypsect=1000h/. -Pmypsect=./1000h Both of these options are valid and equivalent, however the following usage is ambig- uous: -Pmypsect=./. What is the link or load address of this psect? (455) psect "*" not relocated on 0x* byte boundary (Linker) This psect is not relocated on the required boundary. Check the relocatability of the psect and correct the -p option. if necessary. (456) psect "*" not loaded on 0x* boundary (Linker) This psect has a relocatability requirement that is not met by the load address given in a -p option. For example if a psect must be on a 4K byte boundary, you could not start it at 100H. (459) remove failed, error: *, * (xstrip) The creation of the output file failed when removing an intermediate file. (460) rename failed, error: *, * (xstrip) The creation of the output file failed when renaming an intermediate file. (461) can’t create * file "*" (Assembler, Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (464) missing key in avmap file (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (465) undefined symbol "*" in FNBREAK record (Linker) The linker has found an undefined symbol in the FNBREAK record for a non-reentrant function. Contact HI-TECH Support if this is not handwritten assembler code. (466) undefined symbol "*" in FNINDIR record (Linker) The linker has found an undefined symbol in the FNINDIR record for a non-reentrant function. Contact HI-TECH Support if this is not handwritten assembler code. (467) undefined symbol "*" in FNADDR record (Linker) The linker has found an undefined symbol in the FNADDR record for a non-reentrant function. Contact HI-TECH Support if this is not handwritten assembler code.  2010 Microchip Technology Inc. DS51865B-page 283 (468) undefined symbol "*" in FNCALL record (Linker) The linker has found an undefined symbol in the FNCALL record for a non-reentrant function. Contact HI-TECH Support if this is not handwritten assembler code. (469) undefined symbol "*" in FNROOT record (Linker) The linker has found an undefined symbol in the FNROOT record for a non-reentrant function. Contact HI-TECH Support if this is not handwritten assembler code. (470) undefined symbol "*" in FNSIZE record (Linker) The linker has found an undefined symbol in the FNSIZE record for a non-reentrant function. Contact HI-TECH Support if this is not handwritten assembler code. (471) recursive function calls: (Linker) These functions (or function) call each other recursively. One or more of these functions has statically allocated local variables (compiled stack). Either use the reentrant keyword (if supported with this compiler) or recode to avoid recursion, e.g.: int test(int a) { if(a == 5) { /* recursion may not be supported by some compilers */ return test(a++); } return 0; } (472) non-reentrant function "*" appears in multiple call graphs: rooted at "*" and "*" (Linker) This function can be called from both main-line code and interrupt code. Use the reentrant keyword, if this compiler supports it, or recode to avoid using local variables or parameters, or duplicate the function, e.g.: void interrupt my_isr(void) { scan(6); /* scan is called from an interrupt function */ } void process(int a) { scan(a); /* scan is also called from main-line code */ } (473) function "*" is not called from specified interrupt_level (Linker) The indicated function is never called from an interrupt function of the same interrupt level, e.g.: #pragma interrupt_level 1 void foo(void) { ... } #pragma interrupt_level 1 void interrupt bar(void) { // this function never calls foo() } HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 284  2010 Microchip Technology Inc. (474) no psect specified for function variable/argument allocation (Linker) The FNCONF assembler directive which specifies to the linker information regarding the auto/parameter block was never seen. This is supplied in the standard runtime files if necessary. This error may imply that the correct run-time startup module was not linked. Ensure you have used the FNCONF directive if the runtime startup module is hand-written. (475) conflicting FNCONF records (Linker) The linker has seen two conflicting FNCONF directives. This directive should only be specified once and is included in the standard runtime startup code which is normally linked into every program. (476) fixup overflow referencing * * (location 0x* (0x*+*), size *, value 0x*) (Linker) The linker was asked to relocate (fixup) an item that would not fit back into the space after relocation. See the following error message (477) for more information. (477) fixup overflow in expression (location 0x* (0x*+*), size *, value 0x*) (Linker) Fixup is the process conducted by the linker of replacing symbolic references to variables etc, in an assembler instruction with an absolute value. This takes place after positioning the psects (program sections or blocks) into the available memory on the target device. Fixup overflow is when the value determined for a symbol is too large to fit within the allocated space within the assembler instruction. For example, if an assembler instruction has an 8-bit field to hold an address and the linker determines that the symbol that has been used to represent this address has the value 0x110, then clearly this value cannot be inserted into the instruction. The causes for this can be many, but hand-written assembler code is always the first suspect. Badly written C code can also generate assembler that ultimately generates fixup overflow errors. Consider the following error message. main.obj: 8: Fixup overflow in expression (loc 0x1FD (0x1FC+1), size 1, value 0x7FC) This indicates that the file causing the problem was main.obj. This would be typically be the output of compiling main.c or main.as. This tells you the file in which you should be looking. The next number (8 in this example) is the record number in the object file that was causing the problem. If you use the DUMP utility to examine the object file, you can identify the record, however you do not normally need to do this. The location (loc ) of the instruction (0x1FD), the size (in bytes) of the field in the instruction for the value (1) , and the value which is the actual value the symbol represents, is typically the only information needed to track down the cause of this error. Note that a size which is not a multiple of 8 bits will be rounded up to the nearest byte size, i.e. a 7 bit space in an instruction will be shown as 1 byte. Generate an assembler list file for the appropriate module. Look for the address specified in the error message. 7 07FC 0E21 MOVLW 33 8 07FD 6FFC MOVWF _foo 9 07FE 0012 RETURN and to confirm, look for the symbol referenced in the assembler instruction at this address in the symbol table at the bottom of the same file. Symbol Table Fri Aug 12 13:17:37 2004  2010 Microchip Technology Inc. DS51865B-page 285 _foo 01FC _main 07FF In this example, the instruction causing the problem takes an 8-bit offset into a bank of memory, but clearly the address 0x1FC exceeds this size. Maybe the instruction should have been written as: MOVWF (_foo&0ffh) which masks out the top bits of the address containing the bank information. If the assembler instruction that caused this error was generated by the compiler, in the assembler list file look back up the file from the instruction at fault to determine which C statement has generated this instruction. You will then need to examine the C code for possible errors. incorrectly qualified pointers are an common trigger. (478) * range check failed (location 0x* (0x*+*), value 0x* > limit 0x*) (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (479) circular indirect definition of symbol "*" (Linker) The specified symbol has been equated to an external symbol which, in turn, has been equated to the first symbol. (480) function signatures do not match: * (*): 0x*/0x* (Linker) The specified function has different signatures in different modules. This means it has been declared differently, e.g. it may have been prototyped in one module and not another. Check what declarations for the function are visible in the two modules specified and make sure they are compatible, e.g.: extern int get_value(int in); /* and in another module: */ /* this is different to the declaration */ int get_value(int in, char type) { (481) common symbol "*" psect conflict (Linker) A common symbol has been defined to be in more than one psect. (482) symbol "*" is defined more than once in "*" (Assembler) This symbol has been defined in more than one place. The assembler will issue this error if a symbol is defined more than once in the same module, e.g.: _next: MOVE r0, #55 MOVE [r1], r0 _next: ; oops -- choose a different name The linker will issue this warning if the symbol (C or assembler) was defined multiple times in different modules. The names of the modules are given in the error message. Note that C identifiers often have an underscore prepended to their name after compi- lation. (483) symbol "*" can’t be global (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 286  2010 Microchip Technology Inc. (484) psect "*" can’t be in classes "*" and "*" (Linker) A psect cannot be in more than one class. This is either due to assembler modules with conflicting class= options to the PSECT directive, or use of the -C option to the linker, e.g.: psect final,class=CODE finish: /* elsewhere: */ psect final,class=ENTRY (485) unknown "with" psect referenced by psect "*" (Linker) The specified psect has been placed with a psect using the psect with flag. The psect it has been placed with does not exist, e.g.: psect starttext,class=CODE,with=rext ; was that meant to be with text? (486) psect "*" selector value redefined (Linker) The selector value for this psect has been defined more than once. (487) psect "*" type redefined: */* (Linker) This psect has had its type defined differently by different modules. This probably means you are trying to link incompatible object modules, e.g. linking 386 flat model code with 8086 real mode code. (488) psect "*" memory space redefined: */* (Linker) A global psect has been defined in two different memory spaces. Either rename one of the psects or, if they are the same psect, place them in the same memory space using the space psect flag, e.g.: psect spdata,class=RAM,space=0 ds 6 ; elsewhere: psect spdata,class=RAM,space=1 (489) psect "*" memory delta redefined: */* (Linker) A global psect has been defined with two different delta values, e.g.: psect final,class=CODE,delta=2 finish: ; elsewhere: psect final,class=CODE,delta=1 (490) class "*" memory space redefined: */* (Linker) A class has been defined in two different memory spaces. Either rename one of the classes or, if they are the same class, place them in the same memory space. (491) can’t find 0x* words for psect "*" in segment "*" (Linker) One of the main tasks the linker performs is positioning the blocks (or psects) of code and data that is generated from the program into the memory available for the target device. This error indicates that the linker was unable to find an area of free memory large enough to accommodate one of the psects. The error message indicates the name of the psect that the linker was attempting to position and the segment name which is typically the name of a class which is defined with a linker -A option. Section 3.10.1 “Compiler-generated Psects” lists each compiler-generated psect  2010 Microchip Technology Inc. DS51865B-page 287 and what it contains. Typically psect names which are, or include, text relate to program code. Names such as bss or data refer to variable blocks. This error can be due to two reasons. First, the size of the program or the program’s data has exceeded the total amount of space on the selected device. In other words, some part of your device’s memory has completely filled. If this is the case, then the size of the specified psect must be reduced. The second cause of this message is when the total amount of memory needed by the psect being positioned is sufficient, but that this memory is fragmented in such a way that the largest contiguous block is too small to accommodate the psect. The linker is unable to split psects in this situation. That is, the linker cannot place part of a psect at one location and part somewhere else. Thus, the linker must be able to find a contiguous block of memory large enough for every psect. If this is the cause of the error, then the psect must be split into smaller psects if possible. To find out what memory is still available, generate and look in the map file, see Section 2.7.8 “-M: Generate Map File” for information on how to generate a map file. Search for the string UNUSED ADDRESS RANGES. Under this heading, look for the name of the segment specified in the error message. If the name is not present, then all the memory available for this psect has been allocated. If it is present, there will be one address range specified under this segment for each free block of memory. Determine the size of each block and compare this with the number of words specified in the error message. Psects containing code can be reduced by using all the compiler’s optimizations, or restructuring the program. If a code psect must be split into two or more small psects, this requires splitting a function into two or more smaller functions (which may call each other). These functions may need to be placed in new modules. Psects containing data may be reduced when invoking the compiler optimizations, but the effect is less dramatic. The program may need to be rewritten so that it needs less variables. If the default linker options must be changed, this can be done indirectly through the driver using the driver -L- option, see Section 2.7.7 “-L-: Adjust Linker Options Directly”. Section 2.7.8 “-M: Generate Map File” has information on interpreting the map file’s call graph if the compiler you are using uses a compiled stack. (If the string Call graph: is not present in the map file, then the compiled code uses a hardware stack.) If a data psect needs to be split into smaller psects, the definitions for variables will need to be moved to new modules or more evenly spread in the existing modules. Memory allocation for auto variables is entirely handled by the compiler. Other than reducing the number of these variables used, the programmer has little control over their operation. This applies whether the compiled code uses a hardware or compiled stack. For example, after receiving the message: Can’t find 0x34 words (0x34 withtotal) for psect text in segment CODE (error) look in the map file for the ranges of unused memory. UNUSED ADDRESS RANGES CODE 00000244-0000025F 00001000-0000102f RAM 00300014-00301FFB In the CODE segment, there is 0x1c (0x25f-0x244+1) bytes of space available in one block and 0x30 available in another block. Neither of these are large enough to accommodate the psect text which is 0x34 bytes long. Notice, however, that the total amount of memory available is larger than 0x34 bytes. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 288  2010 Microchip Technology Inc. (492) attempt to position absolute psect "*" is illegal (Linker) This psect is absolute and should not have an address specified in a -P option. Either remove the abs psect flag, or remove the -P linker option. (493) origin of psect "*" is defined more than once (Linker) The origin of this psect is defined more than once. There is most likely more than one -p linker option specifying this psect. (494) bad -P format "*/*" (Linker) The -P option given to the linker is malformed. This option specifies placement of a psect, e.g.: -Ptext=10g0h Maybe you meant: -Ptext=10f0h (495) use of both "with=" and "INCLASS/INCLASS" allocation is illegal (Linker) It is not legal to specify both the link and location of a psect as within a class, when that psect was also defined using a with psect flag. (497) psect "*" exceeds max size: *h > *h (Linker) The psect has more bytes in it than the maximum allowed as specified using the size psect flag. (498) psect "*" exceeds address limit: *h > *h (Linker) The maximum address of the psect exceeds the limit placed on it using the limit psect flag. Either the psect needs to be linked at a different location or there is too much code/data in the psect. (499) undefined symbol: (Assembler, Linker) The symbol following is undefined at link time. This could be due to spelling error, or failure to link an appropriate module. (500) undefined symbols: (Linker) A list of symbols follows that were undefined at link time. These errors could be due to spelling error, or failure to link an appropriate module. (501) program entry point is defined more than once (Linker) There is more than one entry point defined in the object files given the linker. End entry point is specified after the END directive. The runtime startup code defines the entry point, e.g.: powerup: goto start END powerup ; end of file and define entry point ; other files that use END should not define another entry point (502) incomplete * record body: length = * (Linker) An object file contained a record with an illegal size. This probably means the file is truncated or not an object file. Contact HI-TECH Support with details.  2010 Microchip Technology Inc. DS51865B-page 289 (503) ident records do not match (Linker) The object files passed to the linker do not have matching ident records. This means they are for different processor types. (504) object code version is greater than *.* (Linker) The object code version of an object module is higher than the highest version the linker is known to work with. Check that you are using the correct linker. Contact HI-TECH Support if the object file if you have not patched the linker. (505) no end record found inobject file (Linker) An object file did not contain an end record. This probably means the file is corrupted or not an object file. Contact HI-TECH Support if the object file was generated by the compiler. (506) object file record too long: *+* (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (507) unexpected end of file in object file (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (508) relocation offset (*) out of range 0..*-*-1 (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (509) illegal relocation size: * (Linker) There is an error in the object code format read by the linker. This either means you are using a linker that is out of date, or that there is an internal error in the assembler or linker. Contact HI-TECH Support with details if the object file was created by the com- piler. (510) complex relocation not supported for -R or -L options (Linker) The linker was given a -R or -L option with file that contain complex relocation. (511) bad complex range check (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (512) unknown complex operator 0x* (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (513) bad complex relocation (Linker) The linker has been asked to perform complex relocation that is not syntactically correct. Probably means an object file is corrupted. (514) illegal relocation type: * (Linker) An object file contained a relocation record with an illegal relocation type. This probably means the file is corrupted or not an object file. Contact HI-TECH Support with details if the object file was created by the compiler. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 290  2010 Microchip Technology Inc. (515) unknown symbol type * (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (516) text record has bad length: *-*-(*+1) < 0 (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (520) function "*" is never called (Linker) This function is never called. This may not represent a problem, but space could be saved by removing it. If you believe this function should be called, check your source code. Some assembler library routines are never called, although they are actually execute. In this case, the routines are linked in a special sequence so that program execution falls through from one routine to the next. (521) call depth exceeded by function "*" (Linker) The call graph shows that functions are nested to a depth greater than specified. (522) library "*" is badly ordered (Linker) This library is badly ordered. It will still link correctly, but it will link faster if better ordered. (523) argument to -W option (*) illegal and ignored (Linker) The argument to the linker option -w is out of range. This option controls two features. For warning levels, the range is -9 to 9. For the map file width, the range is greater than or equal to 10. (524) unable to open list file "*": * (Linker) The named list file could not be opened. The linker would be trying to fixup the list file so that it will contain absolute addresses. Ensure that an assembler list file was generated during the compilation stage. Alternatively, remove the assembler list file generation option from the link step. (525) too many address (memory) spaces; space (*) ignored (Linker) The limit to the number of address spaces (specified with the PSECT assembler directive) is currently 16. (526) psect "*" not specified in -P option (first appears in "*") (Linker) This psect was not specified in a -P or -A option to the linker. It has been linked at the end of the program, which is probably not where you wanted it. (528) no start record; entry point defaults to zero (Linker) None of the object files passed to the linker contained a start record. The start address of the program has been set to zero. This may be harmless, but it is recommended that you define a start address in your startup module by using the END directive. (529) usage: objtohex [-Ssymfile] [object-file [HEX-file]] (Objtohex) Improper usage of the command-line tool objtohex. If you are invoking objtohex directly then please refer to Section 6.3 “Objtohex” for more details. Otherwise this may be an internal compiler error and you should contact HI-TECH Software technical support with details.  2010 Microchip Technology Inc. DS51865B-page 291 (593) can’t find 0x* words (0x* withtotal) for psect "*" in segment "*" (Linker) See message (491). (594) undefined symbol: (Linker) The symbol following is undefined at link time. This could be due to spelling error, or failure to link an appropriate module. (595) undefined symbols: (Linker) A list of symbols follows that were undefined at link time. These errors could be due to spelling error, or failure to link an appropriate module. (596) segment "*" (*-*) overlaps segment "*" (*-*) (Linker) The named segments have overlapping code or data. Check the addresses being assigned by the -P linker option. (599) No psect classes given for COFF write (Cromwell) Cromwell requires that the program memory psect classes be specified to produce a COFF file. Ensure that you are using the -N option as per Section 6.5.2 “-N”. (600) No chip arch given for COFF write (Cromwell) Cromwell requires that the chip architecture be specified to produce a COFF file. Ensure that you are using the -P option as per Table 6-7. (601) Unknown chip arch "*" for COFF write (Cromwell) The chip architecture specified for producing a COFF file isn’t recognized by Cromwell. Ensure that you are using the -P option as per Section 6.5.1 “-Pname[,architecture]” and that the architecture specified matches one of those in Table 6-7. (602) null file format name (Cromwell) The -I or -O option to Cromwell must specify a file format. (603) ambiguous file format name "*" (Cromwell) The input or output format specified to Cromwell is ambiguous. These formats are specified with the -i key and -o key options respectively. (604) unknown file format name "*" (Cromwell) The output format specified to CROMWELL is unknown, e.g.: cromwell -m -P16F877 main.HEX main.sym -ocot and output file type of cot , did you mean cof ? (605) did not recognize format of input file (Cromwell) The input file to Cromwell is required to be COD, Intel HEX, Motorola HEX, COFF, OMF51, P&E or HI-TECH. (606) inconsistent symbol tables (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 292  2010 Microchip Technology Inc. (607) inconsistent line number tables (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (608) bad path specification (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (609) missing processor spec after -P (Cromwell) The -p option to cromwell must specify a processor name. (610) missing psect classes after -N (Cromwell) Cromwell requires that the -N option be given a list of the names of psect classes. (611) too many input files (Cromwell) To many input files have been specified to be converted by CROMWELL. (612) too many output files (Cromwell) To many output file formats have been specified to CROMWELL. (613) no output file format specified (Cromwell) The output format must be specified to CROMWELL. (614) no input files specified (Cromwell) CROMWELL must have an input file to convert. (616) option -Cbaseaddr is illegal with options -R or -L (Linker) The linker option -Cbaseaddr cannot be used in conjunction with either the -R or -L linker options. (618) error reading COD file data (Cromwell) An error occurred reading the input COD file. Confirm the spelling and path of the file specified on the command line. (619) I/O error reading symbol table (Cromwell) The COD file has an invalid format in the specified record. (620) filename index out of range in line number record (Cromwell) The COD file has an invalid value in the specified record. (621) error writing ELF/DWARF section "*" on "*" (Cromwell) An error occurred writing the indicated section to the given file. Confirm the spelling and path of the file specified on the command line. (622) too many type entries (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details.  2010 Microchip Technology Inc. DS51865B-page 293 (623) bad class in type hashing (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (624) bad class in type compare (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (625) too many files in COFF file (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (626) string lookup failed in COFF: get_string() (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (627) missing "*" in SDB file "*" line * column * (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (629) bad storage class "*" in SDB file "*" line * column * (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (630) invalid syntax for prefix list in SDB file "*" (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (631) syntax error at token "*" in SDB file "*" line * column * (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (632) can’t handle address size (*) (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (633) unknown symbol class (*) (Cromwell) Cromwell has encountered a symbol class in the symbol table of a COFF, Microchip COFF, or ICOFF file which it can’t identify. (634) error dumping "*" (Cromwell) Either the input file to CROMWELL is of an unsupported type or that file cannot be dumped to the screen. (635) invalid HEX file "*" on line * (Cromwell) The specified HEX file contains an invalid line. Contact HI-TECH Support if the HEX file was generated by the compiler. (636) checksum error in Intel HEX file "*" on line * (Cromwell, HEXMATE) A checksum error was found at the specified line in the specified Intel HEX file. The HEX file may be corrupt. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 294  2010 Microchip Technology Inc. (637) unknown prefix "*" in SDB file "*" (Cromwell) This is an internal compiler warning. Contact HI-TECH Software technical support with details. (638) version mismatch: 0x* expected (Cromwell) The input Microchip COFF file wasn’t produced using Cromwell. (639) zero bit width in Microchip optional header (Cromwell) The optional header in the input Microchip COFF file indicates that the program or data memory spaces are zero bits wide. (668) prefix list did not match any SDB types (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (669) prefix list matched more than one SDB type (Cromwell) This is an internal compiler error. Contact HI-TECH Software technical support with details. (670) bad argument to -T (Clist) The argument to the -T option to specify tab size was not present or correctly formed. The option expects a decimal integer argument. (671) argument to -T should be in range 1 to 64 (Clist) The argument to the -T option to specify tab size was not in the expected range. The option expects a decimal integer argument ranging from 1 to 64 inclusive. (673) missing filename after * option (Objtohex) The indicated option requires a valid file name. Ensure that the filename argument supplied to this option exists and is spelt correctly. (674) too many references to "*" (Cref) This is an internal compiler error. Contact HI-TECH Software technical support with details. (677) set_fact_bit on pic17! (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (678) case 55 on pic17! (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (679) unknown extraspecial: * (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (680) bad format for -P option (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details.  2010 Microchip Technology Inc. DS51865B-page 295 (681) bad common spec in -P option (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (682) this architecture is not supported by the PICC Lite compiler (Code Generator) A target device other than baseline, Mid-range or Highend was specified. This compiler only supports devices from these architecture families. (683) bank 1 variables are not supported by the PICC Lite compiler (Code Generator) A variable with an absolute address located in bank 1 was detected. This compiler does not support code generation of variables in this bank. (684) bank 2 and 3 variables are not supported by the PICC Lite compiler (Code Generator) A variable with an absolute address located in bank 2 or 3 was detected. This compiler does not support code generation of variables in these banks. (685) bad putwsize() (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (686) bad switch size (*) (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (687) bad pushreg "*" (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (688) bad popreg "*" (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (689) unknown predicate "*" (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (690) interrupt function requires address (Code Generator) The high end PIC devices support multiple interrupts. An @ address is required with the interrupt definition to indicate with which vector this routine is associated, e.g.: void interrupt isr(void) @ 0x10 { /* isr code goes here */ } This construct is not required for midrange PIC devices. (691) interrupt functions not implemented for 12 bit PIC MCU (Code Generator) The 12-bit range of PIC MCU processors do not support interrupts. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 296  2010 Microchip Technology Inc. (692) interrupt function "*" may only have one interrupt level (Code Generator) Only one interrupt level may be associated with an interrupt function. Check to ensure that only one interrupt_level pragma has been used with the function specified. This pragma may be used more than once on main-line functions that are called from interrupt functions. For example: #pragma interrupt_level 0 #pragma interrupt_level 1 /* which is it to be: 0 or 1? */ void interrupt isr(void) { (693) interrupt level may only be 0 (default) or 1 (Code Generator) The only possible interrupt levels are 0 or 1. Check to ensure that all interrupt_level pragmas use these levels. #pragma interrupt_level 2 /* oops -- only 0 or 1 */ void interrupt isr(void) { /* isr code goes here */ } (694) no interrupt strategy available (Code Generator) The processor does not support saving and subsequent restoring of registers during an interrupt service routine. (695) duplicate case label (*) (Code Generator) There are two case labels with the same value in this switch statement, e.g.: switch(in) { case ’0’: /* if this is case ’0’... */ b++; break; case ’0’: /* then what is this case? */ b--; break; } (696) out-of-range case label (*) (Code Generator) This case label is not a value that the controlling expression can yield, and thus this label will never be selected. (697) non-constant case label (Code Generator) A case label in this switch statement has a value which is not a constant. (698) bit variables must be global or static (Code Generator) A bit variable cannot be of type auto. If you require a bit variable with scope local to a block of code or function, qualify it static , e.g.: bit proc(int a) { bit bb; /* oops -- this should be: static bit bb; */ bb = (a > 66); return bb; }  2010 Microchip Technology Inc. DS51865B-page 297 (699) no case labels in switch (Code Generator) There are no case labels in this switch statement, e.g.: switch(input) { } /* there is nothing to match the value of input */ (700) truncation of enumerated value (Code Generator) An enumerated value larger than the maximum value supported by this compiler was detected and has been truncated, e.g.: enum { ZERO, ONE, BIG=0x99999999 } test_case; (701) unreasonable matching depth (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (702) regused(): bad arg to G (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (703) bad GN (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (704) bad RET_MASK (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (705) bad which (*) after I (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (706) bad which in expand() (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (707) bad SX (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (708) bad mod "+" for how = "*" (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (709) metaregister "*" can’t be used directly (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (710) bad U usage (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 298  2010 Microchip Technology Inc. (711) bad how in expand() (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (712) can’t generate code for this expression (Code Generator) This error indicates that a C expression is too difficult for the code generator to actually compile. For successful code generation, the code generator must know how to compile an expression and there must be enough resources (e.g. registers or temporary memory locations) available. Simplifying the expression, e.g. using a temporary variable to hold an intermediate result, may get around this message. Contact HI-TECH Support with details of this message. This error may also be issued if the code being compiled is in some way unusual. For example code which writes to a const-qualified object is illegal and will result in warning messages, but the code generator may unsuccessfully try to produce code to perform the write. (713) bad initialization list (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (714) bad intermediate code (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (715) bad pragma "*" (Code Generator) The code generator has been passed a pragma directive that it does not understand. This implies that the pragma you have used is a HI-TECH specific pragma, but the specific compiler you are using has not implemented this pragma. (716) bad argument to -M option "*" (Code Generator) The code generator has been passed a -M option that it does not understand. This should not happen if it is being invoked by a standard compiler driver. (718) incompatible intermediate code version; should be *.* (Code Generator) The intermediate code file produced by P1 is not the correct version for use with this code generator. This is either that incompatible versions of one or more compilers have been installed in the same directory, or a temporary file error has occurred leading to corruption of a temporary file. Check the setting of the TEMP environment variable. If it refers to a long path name, change it to something shorter. Contact HI-TECH Support with details if required. (720) multiple free: * (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (721) element count must be constant expression (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details.  2010 Microchip Technology Inc. DS51865B-page 299 (722) bad variable syntax in intermediate code (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (723) function definitions nested too deep (Code Generator) This error is unlikely to happen with C code, since C cannot have nested functions! Contact HI-TECH Support with details. (724) bad op (*) in revlog() (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (726) bad op "*" in uconval() (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (727) bad op "*" in bconfloat() (Code Generator) This is an internal code generator error. Contact HI-TECH technical support with details. (728) bad op "*" in confloat() (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (729) bad op "*" in conval() (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (730) bad op "*" (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (731) expression error with reserved word (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (732) initialization of bit types is illegal (Code Generator) Variables of type bit cannot be initialized, e.g.: bit b1 = 1; /* oops! b1 must be assigned after its definition */ (733) bad string "*" in pragma "psect" (Code Generator) The code generator has been passed a pragma psect directive that has a badly formed string, e.g.: #pragma psect text /* redirect text psect into what? */ Maybe you meant something like: #pragma psect text=special_text (734) too many "psect" pragmas (Code Generator) Too many #pragma psect directives have been used. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 300  2010 Microchip Technology Inc. (735) bad string "*" in pragma "stack_size" (Code Generator) The argument to the stack_size pragma is malformed. This pragma must be followed by a number representing the maximum allowed stack size. (737) unknown argument "*" to pragma "switch" (Code Generator) The #pragma switch directive has been used with an invalid switch code generation method. Possible arguments are: auto , simple and direct. (739) error closing output file (Code Generator) The compiler detected an error when closing a file. Contact HI-TECH Support with details. (740) zero dimension array is illegal (Code Generator) The code generator has been passed a declaration that results in an array having a zero dimension. (741) bitfield too large (* bits) (Code Generator) The maximum number of bits in a bit field is the same as the number of bits in an int , e.g. assuming an int is 16 bits wide: struct { unsigned flag : 1; unsigned value : 12; unsigned cont : 6; /* oops -- that’s a total of 19 bits */ } object; (742) function "*" argument evaluation overlapped (Linker) A function call involves arguments which overlap between two functions. This could occur with a call like: void fn1(void) { fn3( 7, fn2(3), fn2(9)); /* Offending call */ } char fn2(char fred) { return fred + fn3(5,1,0); } char fn3(char one, char two, char three) { return one+two+three; } where fn1 is calling fn3 , and two arguments are evaluated by calling fn2 , which in turn calls fn3. The program structure should be modified to prevent this type of call sequence. (743) divide by zero (Code Generator) An expression involving a division by zero has been detected in your code. (744) static object "*" has zero size (Code Generator) A static object has been declared, but has a size of zero.  2010 Microchip Technology Inc. DS51865B-page 301 (745) nodecount = * (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (746) object "*" qualified const, but not initialized (Code Generator) An object has been qualified as const, but there is no initial value supplied at the definition. As this object cannot be written by the C program, this may imply the initial value was accidently omitted. (747) unrecognized option "*" to -Z (Code Generator) This is an internal compiler error. Contact HI-TECH Software technical support with details. (748) variable "*" may be used before set (Code Generator) This variable may be used before it has been assigned a value. Since it is an auto variable, this will result in it having a random value, e.g.: void main(void) { int a; if(a) /* oops -- a has never been assigned a value */ process(); } (749) unknown register name "*" used with pragma (Linker) This is an internal compiler error. Contact HI-TECH Software technical support with details. (750) constant operand to || or && (Code Generator) One operand to the logical operators || or && is a constant. Check the expression for missing or badly placed parentheses. This message may also occur if the global optimizer is enabled and one of the operands is an auto or static local variable whose value has been tracked by the code generator, e.g.: { int a; a = 6; if(a || b) /* a is 6, therefore this is always true */ b++; (751) arithmetic overflow in constant expression (Code Generator) A constant expression has been evaluated by the code generator that has resulted in a value that is too big for the type of the expression. The most common code to trigger this warning is assignments to signed data types. For example: signed char c; c = 0xFF; As a signed 8-bit quantity, c can only be assigned values -128 to 127. The constant is equal to 255 and is outside this range. If you mean to set all bits in this variable, then use either of: c = ~0x0; c = -1; which will set all the bits in the variable regardless of the size of the variable and without warning. This warning can also be triggered by intermediate values overflowing. For example: HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 302  2010 Microchip Technology Inc. unsigned int i; /* assume ints are 16 bits wide */ i = 240 * 137; /* this should be okay, right? */ A quick check with your calculator reveals that 240 * 137 is 32880 which can easily be stored in an unsigned int, but a warning is produced. Why? Because 240 and 137 and both signed int values. Therefore the result of the multiplication must also be a signed int value, but a signed int cannot hold the value 32880. (Both operands are constant values so the code generator can evaluate this expression at compile time, but it must do so following all the ANSI C rules.) The following code forces the multiplication to be performed with an unsigned result: i = 240u * 137; /* force at least one operand to be unsigned */ (752) conversion to shorter data type (Code Generator) Truncation may occur in this expression as the lvalue is of shorter type than the rvalue, e.g.: char a; int b, c; a = b + c; /* int to char conversion may result in truncation */ (753) undefined shift (* bits) (Code Generator) An attempt has been made to shift a value by a number of bits equal to or greater than the number of bits in the data type. This will produce an undefined result on many processors. This is non-portable code and is flagged as having undefined results by the C Standard, e.g.: int input; input <<= 33; /* oops -- that shifts the entire value out */ (754) bitfield comparison out of range (Code Generator) This is the result of comparing a bitfield with a value when the value is out of range of the bitfield. For example, comparing a 2-bit bitfield to the value 5 will never be true as a 2-bit bitfield has a range from 0 to 3, e.g.: struct { unsigned mask : 2; /* mask can hold values 0 to 3 */ } value; int compare(void) { return (value.mask == 6); /* test can } (755) divide by zero (Code Generator) A constant expression that was being evaluated involved a division by zero, e.g.: a /= 0; /* divide by 0: was this what you were intending */ (757) constant conditional branch (Code Generator) A conditional branch (generated by an if , for , while statement etc.) always follows the same path. This will be some sort of comparison involving a variable and a constant expression. For the code generator to issue this message, the variable must have local scope (either auto or static local) and the global optimizer must be enabled, possibly at higher level than 1, and the warning level threshold may need to be lower than the default level of 0.  2010 Microchip Technology Inc. DS51865B-page 303 The global optimizer keeps track of the contents of local variables for as long as is possible during a function. For C code that compares these variables to constants, the result of the comparison can be deduced at compile time and the output code hard coded to avoid the comparison, e.g.: { int a, b; a = 5; /* this can never be false; always perform the true statement */ if(a == 4) b = 6; will produce code that sets a to 5, then immediately sets b to 6. No code will be produced for the comparison if(a == 4). If a was a global variable, it may be that other functions (particularly interrupt functions) may modify it and so tracking the variable cannot be performed. This warning may indicate more than an optimization made by the compiler. It may indicate an expression with missing or badly placed parentheses, causing the evaluation to yield a value different to what you expected. This warning may also be issued because you have written something like while(1). To produce an infinite loop, use for(;;). A similar situation arises with for loops, e.g.: { int a, b; /* this loop must iterate at least once */ for(a=0; a!=10; a++) b = func(a); In this case the code generator can again pick up that a is assigned the value 0, then immediately checked to see if it is equal to 10. Because a is modified during the for loop, the comparison code cannot be removed, but the code generator will adjust the code so that the comparison is not performed on the first pass of the loop; only on the subsequent passes. This may not reduce code size, but it will speed program execu- tion. (758) constant conditional branch: possible use of "=" instead of "==" (Code Generator) There is an expression inside an if or other conditional construct, where a constant is being assigned to a variable. This may mean you have inadvertently used an assignment = instead of a compare == , e.g.: int a, b; /* this can never be false; always perform the true statement */ if(a = 4) b = 6; will assign the value 4 to a, then , as the value of the assignment is always true, the comparison can be omitted and the assignment to b always made. Did you mean: /* this can never be false; always perform the true statement */ if(a == 4) b = 6; which checks to see if a is equal to 4. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 304  2010 Microchip Technology Inc. (759) expression generates no code (Code Generator) This expression generates no output code. Check for things like leaving off the parentheses in a function call, e.g.: int fred; fred; /* this is valid, but has no effect at all */ Some devices require that special function register need to be read to clear hardware flags. To accommodate this, in some instances the code generator does produce code for a statement which only consists of a variable ID. This may happen for variables which are qualified as volatile. Typically the output code will read the variable, but not do anything with the value read. (760) portion of expression has no effect (Code Generator) Part of this expression has no side effects, and no effect on the value of the expression, e.g.: int a, b, c; a = b,c; /* “b” has no effect, was that meant to be a comma? */ (761) sizeof yields 0 (Code Generator) The code generator has taken the size of an object and found it to be zero. This almost certainly indicates an error in your declaration of a pointer, e.g. you may have declared a pointer to a zero length array. In general, pointers to arrays are of little use. If you require a pointer to an array of objects of unknown length, you only need a pointer to a single object that can then be indexed or incremented. (762) constant truncated when assigned to bitfield (Code Generator) A constant value is too large for a bitfield structure member to which it is being assigned, e.g. struct INPUT { unsigned a : 3; unsigned b : 5; } input_grp; input_grp.a = 0x12; /* 12h cannot fit into a 3-bit wide object */ (763) constant left operand to "? :" operator (Code Generator) The left operand to a conditional operator ? is constant, thus the result of the tertiary operator ?: will always be the same, e.g.: a = 8 ? b : c; /* this is the same as saying a = b; */ (764) mismatched comparison (Code Generator) A comparison is being made between a variable or expression and a constant value which is not in the range of possible values for that expression, e.g.: unsigned char c; if(c > 300) /* oops -- how can this be true? */ close(); (765) degenerate unsigned comparison (Code Generator) There is a comparison of an unsigned value with zero, which will always be true or false, e.g.: unsigned char c; if(c >= 0)  2010 Microchip Technology Inc. DS51865B-page 305 will always be true, because an unsigned value can never be less than zero. (766) degenerate signed comparison (Code Generator) There is a comparison of a signed value with the most negative value possible for this type, such that the comparison will always be true or false, e.g.: char c; if(c >= -128) will always be true, because an 8 bit signed char has a maximum negative value of -128. (767) constant truncated to bitfield width (Code Generator) A constant value is too large for a bitfield structure member on which it is operating, e.g. struct INPUT { unsigned a : 3; unsigned b : 5; } input_grp; input_grp.a |= 0x13; /* 13h to large for 3-bit wide object */ (768) constant relational expression (Code Generator) There is a relational expression that will always be true or false. This may be because e.g. you are comparing an unsigned number with a negative value, or comparing a variable with a value greater than the largest number it can represent, e.g.: unsigned int a; if(a == -10) /* if a is unsigned, how can it be -10? */ b = 9; (769) no space for macro definition (Assembler) The assembler has run out of memory. (772) include files nested too deep (Assembler) Macro expansions and include file handling have filled up the assembler’s internal stack. The maximum number of open macros and include files is 30. (773) macro expansions nested too deep (Assembler) Macro expansions in the assembler are nested too deep. The limit is 30 macros and include files nested at one time. (774) too many macro parameters (Assembler) There are too many macro parameters on this macro definition. (776) can’t allocate space for object "*" (offs: *) (Assembler) The assembler has run out of memory. (777) can’t allocate space for opnd structure within object "*", (offs: *) (Assembler) The assembler has run out of memory. (780) too many psects defined (Assembler) There are too many psects defined! Boy, what a program! HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 306  2010 Microchip Technology Inc. (781) can’t enter abs psect (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (782) REMSYM error (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (783) "with" psects are cyclic (Assembler) If Psect A is to be placed “with” Psect B, and Psect B is to be placed “with” Psect A, there is no hierarchy. The with flag is an attribute of a psect and indicates that this psect must be placed in the same memory page as the specified psect. Remove a with flag from one of the psect declarations. Such an assembler declaration may look like: psect my_text,local,class=CODE,with=basecode which will define a psect called my_text and place this in the same page as the psect basecode. (784) overfreed (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (785) too many temporary labels (Assembler) There are too many temporary labels in this assembler file. The assembler allows a maximum of 2000 temporary labels. (787) can’t handle "v_rtype" of * in copyexpr (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (788) invalid character "*" in number (Assembler) A number contained a character that was not part of the range 0-9 or 0-F. (790) end of file inside conditional (Assembler) END-of-FILE was encountered while scanning for an "endif" to match a previous "if". (793) unterminated macro argument (Assembler) An argument to a macro is not terminated. Note that angle brackets ("< >") are used to quote macro arguments. (794) invalid number syntax (Assembler) The syntax of a number is invalid. This can be, e.g. use of 8 or 9 in an octal number, or other malformed numbers. (796) use of LOCAL outside macros is illegal (Assembler) The LOCAL directive is only legal inside macros. It defines local labels that will be unique for each invocation of the macro.  2010 Microchip Technology Inc. DS51865B-page 307 (797) syntax error in LOCAL argument (Assembler) A symbol defined using the LOCAL assembler directive in an assembler macro is syntactically incorrect. Ensure that all symbols and all other assembler identifiers conform with the assembly language of the target device. (798) macro argument may not appear after LOCAL (Assembler) The list of labels after the directive LOCAL may not include any of the formal parameters to the macro, e.g.: mmm MACRO a1 MOVE r0, #a1 LOCAL a1 ; oops -- ; the macro parameter cannot be used with local ENDM (799) REPT argument must be >= 0 (Assembler) The argument to a REPT directive must be greater than zero, e.g.: REPT -2 ; -2 copies of this code? */ MOVE r0, [r1]++ ENDM (800) undefined symbol "*" (Assembler) The named symbol is not defined in this module, and has not been specified GLOBAL. (801) range check too complex (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (802) invalid address after END directive (Assembler) The start address of the program which is specified after the assembler END directive must be a label in the current file. (803) undefined temporary label (Assembler) A temporary label has been referenced that is not defined. Note that a temporary label must have a number >= 0. (804) write error on object file (Assembler) The assembler failed to write to an object file. This may be an internal compiler error. Contact HI-TECH Software technical support with details. (806) attempted to get an undefined object (*) (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (807) attempted to set an undefined object (*) (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (808) bad size in add_reloc() (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 308  2010 Microchip Technology Inc. (809) unknown addressing mode (*) (Assembler) An unknown addressing mode was used in the assembly file. (811) "cnt" too large (*) in display() (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (814) processor type not defined (Assembler) The processor must be defined either from the command line (eg. -16c84), via the PROCESSOR assembler directive, or via the LIST assembler directive. (815) syntax error in chipinfo file at line * (Assembler) The chipinfo file contains non-standard syntax at the specified line. (816) duplicate ARCH specification in chipinfo file "*" at line * (Assembler, Driver) The chipinfo file has a processor section with multiple ARCH values. Only one ARCH value is allowed. If you have not manually edited the chip info file, contact HI-TECH Support with details. (817) unknown architecture in chipinfo file at line * (Assembler, Driver) An chip architecture (family) that is unknown was encountered when reading the chip INI file. (818) duplicate BANKS for "*" in chipinfo file at line * (Assembler) The chipinfo file has a processor section with multiple BANKS values. Only one BANKS value is allowed. If you have not manually edited the chip info file, contact HI-TECH Support with details. (819) duplicate ZEROREG for "*" in chipinfo file at line * (Assembler) The chipinfo file has a processor section with multiple ZEROREG values. Only one ZEROREG value is allowed. If you have not manually edited the chip info file, contact HI-TECH Support with details. (820) duplicate SPAREBIT for "*" in chipinfo file at line * (Assembler) The chipinfo file has a processor section with multiple SPAREBIT values. Only one SPAREBIT value is allowed. If you have not manually edited the chip info file, contact HI-TECH Support with details. (821) duplicate INTSAVE for "*" in chipinfo file at line * (Assembler) The chipinfo file has a processor section with multiple INTSAVE values. Only one INTSAVE value is allowed. If you have not manually edited the chip info file, contact HI-TECH Support with details. (822) duplicate ROMSIZE for "*" in chipinfo file at line * (Assembler) The chipinfo file has a processor section with multiple ROMSIZE values. Only one ROMSIZE value is allowed. If you have not manually edited the chip info file, contact HI-TECH Support with details.  2010 Microchip Technology Inc. DS51865B-page 309 (823) duplicate START for "*" in chipinfo file at line * (Assembler) The chipinfo file has a processor section with multiple START values. Only one START value is allowed. If you have not manually edited the chip info file, contact HI-TECH Support with details. (824) duplicate LIB for "*" in chipinfo file at line * (Assembler) The chipinfo file has a processor section with multiple LIB values. Only one LIB value is allowed. If you have not manually edited the chip info file, contact HI-TECH Support with details. (825) too many RAMBANK lines in chipinfo file for "*" (Assembler) The chipinfo file contains a processor section with too many RAMBANK fields. Reduce the number of values. (826) inverted ram bank in chipinfo file at line * (Assembler, Driver) The second HEX number specified in the RAM field in the chipinfo file must be greater in value than the first. (827) too many COMMON lines in chipinfo file for "*" (Assembler) There are too many lines specifying common (access bank) memory in the chip configuration file. (828) inverted common bank in chipinfo file at line * (Assembler, Driver) The second HEX number specified in the COMMON field in the chipinfo file must be greater in value than the first. Contact HI-TECH Support if you have not modified the chipinfo INI file. (829) unrecognized line in chipinfo file at line * (Assembler) The chipinfo file contains a processor section with an unrecognized line. Contact HI-TECH Support if the INI has not been edited. (830) missing ARCH specification for "*" in chipinfo file (Assembler) The chipinfo file has a processor section without an ARCH values. The architecture of the processor must be specified. Contact HI-TECH Support if the chipinfo file has not been modified. (832) empty chip info file "*" (Assembler) The chipinfo file contains no data. If you have not manually edited the chip info file, contact HI-TECH Support with details. (833) no valid entries in chipinfo file (Assembler) The chipinfo file contains no valid processor descriptions. (834) page width must be >= 60 (Assembler) The listing page width must be at least 60 characters. Any less will not allow a properly formatted listing to be produced, e.g.: LIST C=10 ; the page width will need to be wider than this HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 310  2010 Microchip Technology Inc. (835) form length must be >= 15 (Assembler) The form length specified using the -F length option must be at least 15 lines. Setting this length to zero is allowed and turns off paging altogether. The default value is zero (pageless). (836) no file arguments (Assembler) The assembler has been invoked without any file arguments. It cannot assemble any- thing. (839) relocation too complex (Assembler) The complex relocation in this expression is too big to be inserted into the object file. (840) phase error (Assembler) The assembler has calculated a different value for a symbol on two different passes. This is probably due to bizarre use of macros or conditional assembly. (841) bad source/destination for movfp/movpf instruction (Assembler) The absolute address specified with the MOVFP/MOVPF instruction is too large. (842) bad bit number (Assembler) A bit number must be an absolute expression in the range 0-7. (843) a macro name can’t also be an EQU/SET symbol (Assembler) An EQU or SET symbol has been found with the same name as a macro. This is not allowed. For example: getval MACRO MOV r0, r1 ENDM getval EQU 55h ; oops -- choose a different name to the macro (844) lexical error (Assembler) An unrecognized character or token has been seen in the input. (845) symbol "*" defined more than once (Assembler) This symbol has been defined in more than one place. The assembler will issue this error if a symbol is defined more than once in the same module, e.g.: _next: MOVE r0, #55 MOVE [r1], r0 _next: ; oops -- choose a different name The linker will issue this warning if the symbol (C or assembler) was defined multiple times in different modules. The names of the modules are given in the error message. Note that C identifiers often have an underscore prepended to their name after compi- lation. (846) relocation error (Assembler) It is not possible to add together two relocatable quantities. A constant may be added to a relocatable value, and two relocatable addresses in the same psect may be subtracted. An absolute value must be used in various places where the assembler must know a value at assembly time.  2010 Microchip Technology Inc. DS51865B-page 311 (847) operand error (Assembler) The operand to this opcode is invalid. Check your assembler reference manual for the proper form of operands for this instruction. (848) symbol has been declared EXTERN (Assembler) An assembly label uses the same name as a symbol that has already been declared as EXTERN. (849) illegal instruction for this processor (Assembler) The instruction is not supported by this processor. (850) PAGESEL not usable with this processor (Assembler) The PAGESEL pseudo-instruction is not usable with the device selected. (851) illegal destination (Assembler) The destination (either ,f or ,w ) is not correct for this instruction. (852) radix must be from 2 - 16 (Assembler) The radix specified using the RADIX assembler directive must be in the range from 2 (binary) to 16 (hexadecimal). (853) invalid size for FNSIZE directive (Assembler) The assembler FNSIZE assembler directive arguments must be positive constants. (855) ORG argument must be a positive constant (Assembler) An argument to the ORG assembler directive must be a positive constant or a symbol which has been equated to a positive constant, e.g.: ORG -10 /* this must a positive offset to the current psect */ (856) ALIGN argument must be a positive constant (Assembler) The align assembler directive requires a non-zero positive integer argument. (857) psect may not be local and global (Linker) A local psect may not have the same name as a global psect, e.g.: psect text,class=CODE ; text is implicitly global MOVE r0, r1 ; elsewhere: psect text,local,class=CODE MOVE r2, r4 The global flag is the default for a psect if its scope is not explicitly stated. (859) argument to C option must specify a positive constant (Assembler) The parameter to the LIST assembler control’s C= option (which sets the column width of the listing output) must be a positive decimal constant number, e.g.: LIST C=a0h ; constant must be decimal and positive, try: LIST C=80 HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 312  2010 Microchip Technology Inc. (860) page width must be >= 49 (Assembler) The page width suboption to the LIST assembler directive must specify a with of at least 49. (861) argument to N option must specify a positive constant (Assembler) The parameter to the LIST assembler control’s N option (which sets the page length for the listing output) must be a positive constant number, e.g.: LIST N=-3 ; page length must be positive (862) symbol is not external (Assembler) A symbol has been declared as EXTRN but is also defined in the current module. (863) symbol can’t be both extern and public (Assembler) If the symbol is declared as extern, it is to be imported. If it is declared as public, it is to be exported from the current module. It is not possible for a symbol to be both. (864) argument to "size" psect flag must specify a positive constant (Assembler) The parameter to the PSECT assembler directive’s size option must be a positive constant number, e.g.: PSECT text,class=CODE,size=-200 ; a negative size? (865) psect flag "size" redefined (Assembler) The size flag to the PSECT assembler directive is different from a previous PSECT directive, e.g.: psect spdata,class=RAM,size=400 ; elsewhere: psect spdata,class=RAM,size=500 (866) argument to "reloc" psect flag must specify a positive constant (Assembler) The parameter to the PSECT assembler directive’s reloc option must be a positive constant number, e.g.: psect test,class=CODE,reloc=-4 ; the reloc must be positive (867) psect flag "reloc" redefined (Assembler) The reloc flag to the PSECT assembler directive is different from a previous PSECT directive, e.g.: psect spdata,class=RAM,reloc=4 ; elsewhere: psect spdata,class=RAM,reloc=8 (868) argument to "delta" psect flag must specify a positive constant (Assembler) The parameter to the PSECT assembler directive’s DELTA option must be a positive constant number, e.g.: PSECT text,class=CODE,delta=-2 ; negative delta value doesn’t make sense  2010 Microchip Technology Inc. DS51865B-page 313 (869) psect flag "delta" redefined (Assembler) The ’DELTA’ option of a psect has been redefined more than once in the same module. (870) argument to "pad" psect flag must specify a positive constant (Assembler) The parameter to the PSECT assembler directive’s ’PAD’ option must be a non-zero positive integer. (871) argument to "space" psect flag must specify a positive constant (Assembler) The parameter to the PSECT assembler directive’s space option must be a positive constant number, e.g.: PSECT text,class=CODE,space=-1 ; space values start at zero (872) psect flag "space" redefined (Assembler) The space flag to the PSECT assembler directive is different from a previous PSECT directive, e.g.: psect spdata,class=RAM,space=0 ; elsewhere: psect spdata,class=RAM,space=1 (873) a psect may only be in one class (Assembler) You cannot assign a psect to more than one class. The psect was defined differently at this point than when it was defined elsewhere. A psect’s class is specified via a flag as in the following: psect text,class=CODE Look for other psect definitions that specify a different class name. (874) a psect may only have one "with" option (Assembler) A psect can only be placed with one other psect. A psect’s with option is specified via a flag as in the following: psect bss,with=data Look for other psect definitions that specify a different with psect name. (875) bad character constant in expression (Assembler) The character constant was expected to consist of only one character, but was found to be greater than one character or none at all. An assembler specific example: MOV r0, #’12’ ; ’12’ specifies two characters (876) syntax error (Assembler) A syntax error has been detected. This could be caused a number of things. (877) yacc stack overflow (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (878) -S option used: "*" ignored (Driver) The indicated assembly file has been supplied to the driver in conjunction with the -S option. The driver really has nothing to do since the file is already an assembly file. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 314  2010 Microchip Technology Inc. (880) invalid number of parameters. Use "* –HELP" for help (Driver) Improper command-line usage of the of the compiler’s driver. (881) setup succeeded (Driver) The compiler has been successfully setup using the --setup driver option. (883) setup failed (Driver) The compiler was not successfully setup using the --setup driver option. Ensure that the directory argument to this option is spelt correctly, is syntactically correct for your host operating system and it exists. (884) please ensure you have write permissions to the configuration file (Driver) The compiler was not successfully setup using the --setup driver option because the driver was unable to access the XML configuration file. Ensure that you have write permission to this file. The driver will search the following configuration files in order: • the file specified by the environment variable HTC_XML • the file /etc/htsoft.xml if the directory ’/etc ’ is writable and there is no .htsoft.xml file in your home directory • the file .htsoft.xml file in your home directory If none of the files can be located then the above error will occur. (889) this * compiler has expired (Driver) The demo period for this compiler has concluded. (890) contact HI-TECH Software to purchase and re-activate this compiler (Driver) The evaluation period of this demo installation of the compiler has expired. You will need to purchase the compiler to re-activate it. If however you sincerely believe the evaluation period has ended prematurely please contact HI-TECH technical support. (891) can’t open psect usage map file "*": * (Driver) The driver was unable to open the indicated file. The psect usage map file is generated by the driver when the driver option --summary=file is used. Ensure that the file is not open in another application. (892) can’t open memory usage map file "*": * (Driver) The driver was unable to open the indicated file. The memory usage map file is generated by the driver when the driver option --summary=file is used. Ensure that the file is not open in another application. (893) can’t open HEX usage map file "*": * (Driver) The driver was unable to open the indicated file. The HEX usage map file is generated by the driver when the driver option --summary=file is used. Ensure that the file is not open in another application. (894) unknown source file type "*" (Driver) The extension of the indicated input file could not be determined. Only files with the extensions as , c , obj , usb , p1 , lib or HEX are identified by the driver.  2010 Microchip Technology Inc. DS51865B-page 315 (895) can’t request and specify options in the one command (Driver) The usage of the driver options --getoption and --setoption is mutually exclu- sive. (896) no memory ranges specified for data space (Driver) No on-chip or external memory ranges have been specified for the data space memory for the device specified. (897) no memory ranges specified for program space (Driver) No on-chip or external memory ranges have been specified for the program space memory for the device specified. (899) can’t open option file "*" for application "*": * (Driver) An option file specified by a --getoption or --setoption driver option could not be opened. If you are using the --setoption option ensure that the name of the file is spelt correctly and that it exists. If you are using the --getoption option ensure that this file can be created at the given location or that it is not in use by any other appli- cation. (900) exec failed: * (Driver) The subcomponent listed failed to execute. Does the file exist? Try re-installing the compiler. (902) no chip name specified; use "* –CHIPINFO" to see available chip names (Driver) The driver was invoked without selecting what chip to build for. Running the driver with the –CHIPINFO option will display a list of all chips that could be selected to build for. (904) illegal format specified in "*" option (Driver) The usage of this option was incorrect. Confirm correct usage with –HELP or refer to the part of the manual that discusses this option. (905) illegal application specified in "*" option (Driver) The application given to this option is not understood or does not belong to the com- piler. (907) unknown memory space tag "*" in "*" option specification (Driver) A parameter to this memory option was a string but did not match any valid tags. Refer to the section of this manual that describes this option to see what tags (if any) are valid for this device. (908) exit status = * (Driver) One of the subcomponents being executed encountered a problem and returned an error code. Other messages should have been reported by the subcomponent to explain the problem that was encountered. (913) "*" option may cause compiler errors in some standard header files (Driver) Using this option will invalidate some of the qualifiers used in the standard header files resulting in errors. This issue and its solution are detailed in the section of this manual that specifically discusses this option. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 316  2010 Microchip Technology Inc. (915) no room for arguments (Preprocessor, Parser, Code Generator, Linker, Objtohex) The code generator could not allocate any more memory. (917) argument too long (Preprocessor, Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (918) *: no match (Preprocessor, Parser) This is an internal compiler error. Contact HI-TECH Software technical support with details. (919) * in chipinfo file "*" at line * (Driver) The specified parameter in the chip configuration file is illegal. (920) empty chipinfo file (Driver, Assembler) The chip configuration file was able to be opened but it was empty. Try re-installing the compiler. (922) chip "*" not present in chipinfo file "*" (Driver) The chip selected does not appear in the compiler’s chip configuration file. You may need to contact HI-TECH Software to see if support for this device is available or upgrade the version of your compiler. (923) unknown suboption "*" (Driver) This option can take suboptions, but this suboption is not understood. This may just be a simple spelling error. If not, –HELP to look up what suboptions are permitted here. (924) missing argument to "*" option (Driver) This option expects more data but none was given. Check the usage of this option. (925) extraneous argument to "*" option (Driver) This option does not accept additional data, yet additional data was given. Check the usage of this option. (926) duplicate "*" option (Driver) This option can only appear once, but appeared more than once. (928) bad "*" option value (Driver, Assembler) The indicated option was expecting a valid hexadecimal integer argument. (929) bad "*" option ranges (Driver) This option was expecting a parameter in a range format (start_of_range-end_of_range ), but the parameter did not conform to this syntax. (930) bad "*" option specification (Driver) The parameters to this option were not specified correctly. Run the driver with –HELP or refer to the driver’s chapter in this manual to verify the correct usage of this option.  2010 Microchip Technology Inc. DS51865B-page 317 (931) command file not specified (Driver) Command file to this application, expected to be found after ’@’ or ’<’ on the command line was not found. (939) no file arguments (Driver) The driver has been invoked with no input files listed on its command line. If you are getting this message while building through a third party IDE, perhaps the IDE could not verify the source files to compile or object files to link and withheld them from the command line. (940) *-bit checksum * placed at * (Objtohex) Presenting the result of the requested checksum calculation. (941) bad "*" assignment; USAGE: ** (Hexmate) An option to HEXMATE was incorrectly used or incomplete. Follow the usage supplied by the message and ensure that the option has been formed correctly and completely. (942) unexpected character on line * of file "*" (Hexmate) File contains a character that was not valid for this type of file, the file may be corrupt. For example, an Intel HEX file is expected to contain only ASCII representations of hexadecimal digits, colons (:) and line formatting. The presence of any other characters will result in this error. (944) data conflict at address *h between * and * (Hexmate) Sources to Hexmate request differing data to be stored to the same address. To force one data source to override the other, use the ’+’ specifier. If the two named sources of conflict are the same source, then the source may contain an error. (945) checksum range (*h to *h) contained an indeterminate value (Hexmate) The range for this checksum calculation contained a value that could not be resolved. This can happen if the checksum result was to be stored within the address range of the checksum calculation. (948) checksum result width must be between 1 and 4 bytes (Hexmate) The requested checksum byte size is illegal. Checksum results must be within 1 to 4 bytes wide. Check the parameters to the -CKSUM option. (949) start of checksum range must be less than end of range (Hexmate) The -CKSUM option has been given a range where the start is greater than the end. The parameters may be incomplete or entered in the wrong order. (951) start of fill range must be less than end of range (Hexmate) The -FILL option has been given a range where the start is greater than the end. The parameters may be incomplete or entered in the wrong order. (953) unknown -HELP sub-option: * (Hexmate) Invalid sub-option passed to -HELP. Check the spelling of the sub-option or use -HELP with no sub-option to list all options. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 318  2010 Microchip Technology Inc. (956) -SERIAL value must be between 1 and * bytes long (Hexmate) The serial number being stored was out of range. Ensure that the serial number can be stored in the number of bytes permissible by this option. (958) too many input files specified; * file maximum (Hexmate) Too many file arguments have been used. Try merging these files in several stages rather than in one command. (960) unexpected record type (*) on line * of "*" (Hexmate) Intel HEX file contained an invalid record type. Consult the Intel HEX format specification for valid record types. (962) forced data conflict at address *h between * and * (Hexmate) Sources to HEXMATE force differing data to be stored to the same address. More than one source using the ’+’ specifier store data at the same address. The actual data stored there may not be what you expect. (963) checksum range includes voids or unspecified memory locations (Hexmate) Checksum range had gaps in data content. The runtime calculated checksum is likely to differ from the compile-time checksum due to gaps/unused byes within the address range that the checksum is calculated over. Filling unused locations with a known value will correct this. (964) unpaired nibble in -FILL value will be truncated (Hexmate) The hexadecimal code given to the FILL option contained an incomplete byte. The incomplete byte (nibble) will be disregarded. (965) -STRPACK option not yet implemented, option will be ignored (Hexmate) This option currently is not available and will be ignored. (966) no END record for HEX file "*" (Hexmate) Intel HEX file did not contain a record of type END. The HEX file may be incomplete. (967) unused function definition "*" (from line *) (Parser) The indicated static function was never called in the module being compiled. Being static, the function cannot be called from other modules so this warning implies the function is never used. Either the function is redundant, or the code that was meant to call it was excluded from compilation or misspelt the name of the function. (968) unterminated string (Assembler) A string constant appears not to have a closing quote missing. (969) end of string in format specifier (Parser) The format specifier for the printf() style function is malformed. (970) character not valid at this point in format specifier (Parser) The printf() style format specifier has an illegal character.  2010 Microchip Technology Inc. DS51865B-page 319 (971) type modifiers not valid with this format (Parser) Type modifiers may not be used with this format. (972) only modifiers "h" and "l" valid with this format (Parser) Only modifiers h (short ) and l (long ) are legal with this printf format specifier. (973) only modifier "l" valid with this format (Parser) The only modifier that is legal with this format is l (for long). (974) type modifier already specified (Parser) This type modifier has already be specified in this type. (975) invalid format specifier or type modifier (Parser) The format specifier or modifier in the printf-style string is illegal for this particular for- mat. (976) field width not valid at this point (Parser) A field width may not appear at this point in a printf() type format specifier. (978) this identifier is already an enum tag (Parser) This identifier following a struct or union keyword is already the tag for an enumerated type, and thus should only follow the keyword enum , e.g.: enum IN {ONE=1, TWO}; struct IN { /* oops -- IN is already defined */ int a, b; }; (979) this identifier is already a struct tag (Parser) This identifier following a union or enum keyword is already the tag for a structure, and thus should only follow the keyword struct , e.g.: struct IN { int a, b; }; enum IN {ONE=1, TWO}; /* oops -- IN is already defined */ (980) this identifier is already a union tag (Parser) This identifier following a struct or enum keyword is already the tag for a union , and thus should only follow the keyword union , e.g.: union IN { int a, b; }; enum IN {ONE=1, TWO}; /* oops -- IN is already defined */ (981) pointer required (Parser) A pointer is required here, e.g.: struct DATA data; data->a = 9; /* data is a structure, not a pointer to a structure */ HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 320  2010 Microchip Technology Inc. (982) unknown op "*" in nxtuse() (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (983) storage class redeclared (Parser) A variable previously declared as being static , has now be redeclared as extern. (984) type redeclared (Parser) The type of this function or object has been redeclared. This can occur because of two incompatible declarations, or because an implicit declaration is followed by an incompatible declaration, e.g.: int a; char a; /* oops -- what is the correct type? */ (985) qualifiers redeclared (Parser) This function or variable has different qualifiers in different declarations. (986) enum member redeclared (Parser) A member of an enumeration is defined twice or more with differing values. Does the member appear twice in the same list or does the name of the member appear in more than one enum list? (987) arguments redeclared (Parser) The data types of the parameters passed to this function do not match its prototype. (988) number of arguments redeclared (Parser) The number of arguments in this function declaration does not agree with a previous declaration of the same function. (989) module has code below file base of *h (Linker) This module has code below the address given, but the -C option has been used to specify that a binary output file is to be created that is mapped to this address. This would mean code from this module would have to be placed before the beginning of the file! Check for missing psect directives in assembler files. (990) modulus by zero in #if; zero result assumed (Preprocessor) A modulus operation in a #if expression has a zero divisor. The result has been assumed to be zero, e.g.: #define ZERO 0 #if FOO%ZERO /* this will have an assumed result of 0 */ #define INTERESTING #endif (991) integer expression required (Parser) In an enum declaration, values may be assigned to the members, but the expression must evaluate to a constant of type int , e.g.: enum {one = 1, two, about_three = 3.12}; /* no non-int values allowed */  2010 Microchip Technology Inc. DS51865B-page 321 (992) can’t find op (Assembler) This is an internal compiler error. Contact HI-TECH Software technical support with details. (993) some command-line options are disabled (Driver) The compiler is operating in demo mode. Some command-line options are disabled. (994) some command-line options are disabled and compilation is delayed (Driver) The compiler is operating in demo mode. Some command-line options are disabled, the compilation speed will be slower. (995) some command-line options are disabled, code size is limited to 16kB, compilation is delayed (Driver) The compiler is operating in demo mode. Some command-line options are disabled, the compilation speed will be slower, and the maximum allowed code size is limited to 16kB. (1015) missing "*" specification in chipinfo file "*" at line * (Driver) This attribute was expected to appear at least once but was not defined for this chip. (1016) missing argument* to "*" specification in chipinfo file "*" at line * (Driver) This value of this attribute is blank in the chip configuration file. (1017) extraneous argument* to "*" specification in chipinfo file "*" at line * (Driver) There are too many attributes for the listed specification in the chip configuration file. (1018) illegal number of "*" specification* (* found; * expected) in chipinfo file "*" at line * (Driver) This attribute was expected to appear a certain number of times but it did not for this chip. (1019) duplicate "*" specification in chipinfo file "*" at line * (Driver) This attribute can only be defined once but has been defined more than once for this chip. (1020) unknown attribute "*" in chipinfo file "*" at line * (Driver) The chip configuration file contains an attribute that is not understood by this version of the compiler. Has the chip configuration file or the driver been replaced with an equivalent component from another version of this compiler? (1021) syntax error reading "*" value in chipinfo file "*" at line * (Driver) The chip configuration file incorrectly defines the specified value for this device. If you are modifying this file yourself, take care and refer to the comments at the beginning of this file for a description on what type of values are expected here. HI-TECH C® for PIC10/12/16 User’s Guide DS51865B-page 322  2010 Microchip Technology Inc. (1022) syntax error reading "*" range in chipinfo file "*" at line * (Driver) The chip configuration file incorrectly defines the specified range for this device. If you are modifying this file yourself, take care and refer to the comments at the beginning of this file for a description on what type of values are expected here. (1024) syntax error in chipinfo file "*" at line * (Driver) The chip configuration file contains a syntax error at the line specified. (1025) unknown architecture in chipinfo file "*" at line * (Driver) The attribute at the line indicated defines an architecture that is unknown to this com- piler. (1026) missing architecture in chipinfo file "*" at line * (Assembler) The chipinfo file has a processor section without an ARCH values. The architecture of the processor must be specified. Contact HI-TECH Support if the chipinfo file has not been modified. (1027) activation was successful (Driver) The compiler was successfully activated. (1028) activation was not successful - error code (*) (Driver) The compiler did not activated successfully. (1029) compiler not installed correctly - error code (*) (Driver) This compiler has failed to find any activation information and cannot proceed to execute. The compiler may have been installed incorrectly or incompletely. The error code quoted can help diagnose the reason for this failure. You may be asked for this failure code if contacting HI-TECH Software for assistance with this problem. (1030) Hexmate - Intel HEX editing utility (Build 1.%i) (Hexmate) Indicating the version number of the HEXMATE being executed. (1031) USAGE: * [input1.HEX] [input2.HEX]... [inputN.HEX] [options] (Hexmate) The suggested usage of HEXMATE. (1032) use –HELP=