1 #LyX 1.2 created this file. For more info see http://www.lyx.org/
15 \use_numerical_citations 0
16 \paperorientation portrait
19 \paragraph_separation indent
21 \quotes_language swedish
29 Please note: double dashed longoptions (e.g.
30 --version) need three dashes in this document to be visable in html and
34 SDCC Compiler User Guide
38 \begin_inset LatexCommand \tableofcontents{}
55 is a Freeware, retargettable, optimizing ANSI-C compiler by
59 designed for 8 bit Microprocessors.
60 The current version targets Intel MCS51 based Microprocessors(8051,8052,
61 etc), Zilog Z80 based MCUs, and the Dallas DS80C390 variant.
62 It can be retargetted for other microprocessors, support for PIC, AVR and
63 186 is under development.
64 The entire source code for the compiler is distributed under GPL.
65 SDCC uses ASXXXX & ASLINK, a Freeware, retargettable assembler & linker.
66 SDCC has extensive language extensions suitable for utilizing various microcont
67 rollers and underlying hardware effectively.
72 In addition to the MCU specific optimizations SDCC also does a host of standard
76 global sub expression elimination,
79 loop optimizations (loop invariant, strength reduction of induction variables
83 constant folding & propagation,
99 For the back-end SDCC uses a global register allocation scheme which should
100 be well suited for other 8 bit MCUs.
105 The peep hole optimizer uses a rule based substitution mechanism which is
111 Supported data-types are:
114 char (8 bits, 1 byte),
117 short and int (16 bits, 2 bytes),
120 long (32 bit, 4 bytes)
127 The compiler also allows
129 inline assembler code
131 to be embedded anywhere in a function.
132 In addition, routines developed in assembly can also be called.
136 SDCC also provides an option (--cyclomatic) to report the relative complexity
138 These functions can then be further optimized, or hand coded in assembly
144 SDCC also comes with a companion source level debugger SDCDB, the debugger
145 currently uses ucSim a freeware simulator for 8051 and other micro-controllers.
150 The latest version can be downloaded from
151 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
163 All packages used in this compiler system are
171 ; source code for all the sub-packages (pre-processor, assemblers, linkers
172 etc) is distributed with the package.
173 This documentation is maintained using a freeware word processor (LyX).
175 This program is free software; you can redistribute it and/or modify it
176 under the terms of the GNU General Public License as published by the Free
177 Software Foundation; either version 2, or (at your option) any later version.
178 This program is distributed in the hope that it will be useful, but WITHOUT
179 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
180 FOR A PARTICULAR PURPOSE.
181 See the GNU General Public License for more details.
182 You should have received a copy of the GNU General Public License along
183 with this program; if not, write to the Free Software Foundation, 59 Temple
184 Place - Suite 330, Boston, MA 02111-1307, USA.
185 In other words, you are welcome to use, share and improve this program.
186 You are forbidden to forbid anyone else to use, share and improve what
188 Help stamp out software-hoarding!
191 Typographic conventions
194 Throughout this manual, we will use the following convention.
195 Commands you have to type in are printed in
203 Code samples are printed in
208 Interesting items and new terms are printed in
213 Compatibility with previous versions
216 This version has numerous bug fixes compared with the previous version.
217 But we also introduced some incompatibilities with older versions.
218 Not just for the fun of it, but to make the compiler more stable, efficient
225 short is now equivalent to int (16 bits), it used to be equivalent to char
226 (8 bits) which is not ANSI compliant
229 the default directory for gcc-builds where include, library and documention
230 files are stored is now in /usr/local/share
233 char type parameters to vararg functions are casted to int unless explicitly
250 will push a as an int and as a char resp.
253 option ---regextend has been removed
256 option ---noregparms has been removed
259 option ---stack-after-data has been removed
264 <pending: more incompatibilities?>
270 What do you need before you start installation of SDCC? A computer, and
272 The preferred method of installation is to compile SDCC from source using
274 For Windows some pre-compiled binary distributions are available for your
276 You should have some experience with command line tools and compiler use.
282 The SDCC home page at
283 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
287 is a great place to find distribution sets.
288 You can also find links to the user mailing lists that offer help or discuss
289 SDCC with other SDCC users.
290 Web links to other SDCC related sites can also be found here.
291 This document can be found in the DOC directory of the source package as
293 Some of the other tools (simulator and assembler) included with SDCC contain
294 their own documentation and can be found in the source distribution.
295 If you want the latest unreleased software, the complete source package
296 is available directly by anonymous CVS on cvs.sdcc.sourceforge.net.
299 Wishes for the future
302 There are (and always will be) some things that could be done.
303 Here are some I can think of:
310 char KernelFunction3(char p) at 0x340;
316 If you can think of some more, please send them to the list.
322 <pending: And then of course a proper index-table
323 \begin_inset LatexCommand \index{index}
333 Install and search paths
336 Linux (and other gcc-builds like Solaris, Cygwin, Mingw and OSX) by default
337 install in /usr/local.
338 You can override this when configuring with ---prefix-path.
339 Subdirs used will be bin, share/sdcc/include, share/sdcc/lib and share/sdcc/doc.
341 Windows MSVC and Borland builds will install in one single tree (e.g.
342 /sdcc) with subdirs bin, lib, include and doc.
346 The paths searched when running the compiler are as follows (the first catch
350 Binary files (preprocessor, assembler and linker):
352 - the path of argv[0] (if available)
355 \begin_inset Quotes sld
359 \begin_inset Quotes srd
365 \begin_inset Quotes sld
369 \begin_inset Quotes srd
382 \begin_inset Quotes sld
386 \begin_inset Quotes srd
392 \begin_inset Quotes sld
396 \begin_inset Quotes srd
401 - /usr/local/share/sdcc/include (gcc builds)
403 - path(arv[0])/../include and then /sdcc/include (as a last resort for windoze
404 msvc and borland builds)
411 is auto-appended by the compiler, e.g.
412 small, large, z80, ds390 etc.):
417 \begin_inset Quotes sld
421 \begin_inset Quotes srd
431 \begin_inset Quotes sld
435 \begin_inset Quotes srd
444 - /usr/local/share/sdcc/lib/
450 - path(argv[0])/../lib/
458 (as a last resort for windoze msvc and borland builds)
461 Documentation (although never really searched for, you have to do that yourself
465 \begin_inset Quotes sld
469 \begin_inset Quotes srd
474 - /usr/local/share/sdcc/doc (gcc builds)
476 - /sdcc/doc (windoze msvc and borland builds)
479 So, for windoze it is highly recommended to set the environment variable
480 SDCCHOME to prevent needless usage of -I and -L options.
481 For gcc-builds SDCCHOME should only be set when sdcc is installed in non-standa
485 Linux and other gcc-based systems (cygwin, mingw, osx)
490 Download the source package
492 either from the SDCC CVS repository or from the
493 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
499 , it will be named something like sdcc
508 Bring up a command line terminal, such as xterm.
513 Unpack the file using a command like:
516 "tar -xzf sdcc.src.tgz
521 , this will create a sub-directory called sdcc with all of the sources.
524 Change directory into the main SDCC directory, for example type:
541 This configures the package for compilation on your system.
557 All of the source packages will compile, this can take a while.
573 This copies the binary executables, the include files, the libraries and
574 the documentation to the install directories.
578 \layout Subsubsection
580 Windows Install Using a Binary Package
583 Download the binary package and unpack it using your favorite unpacking
584 tool (gunzip, WinZip, etc).
585 This should unpack to a group of sub-directories.
586 An example directory structure after unpacking the mingw package is: c:
592 bin for the executables, c:
612 lib for the include and libraries.
615 Adjust your environment variable PATH to include the location of the bin
616 directory or start sdcc using the full path.
617 \layout Subsubsection
619 Windows Install Using Cygwin and Mingw
622 Follow the instruction in
624 Linux and other gcc-based systems
627 \layout Subsubsection
629 Windows Install Using Microsoft Visual C++ 6.0/NET
634 Download the source package
636 either from the SDCC CVS repository or from the
637 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
643 , it will be named something like sdcc
650 SDCC is distributed with all the projects, workspaces, and files you need
651 to build it using Visual C++ 6.0/NET.
652 The workspace name is 'sdcc.dsw'.
653 Please note that as it is now, all the executables are created in a folder
657 Once built you need to copy the executables from sdcc
661 bin before runnng SDCC.
666 In order to build SDCC with Visual C++ 6.0/NET you need win32 executables
667 of bison.exe, flex.exe, and gawk.exe.
668 One good place to get them is
669 \begin_inset LatexCommand \url[here]{http://unxutils.sourceforge.net}
677 Download the file UnxUtils.zip.
678 Now you have to install the utilities and setup Visual C++ so it can locate
679 the required programs.
680 Here there are two alternatives (choose one!):
687 a) Extract UnxUtils.zip to your C:
689 hard disk PRESERVING the original paths, otherwise bison won't work.
690 (If you are using WinZip make certain that 'Use folder names' is selected)
694 b) In the Visual C++ IDE click Tools, Options, select the Directory tab,
695 in 'Show directories for:' select 'Executable files', and in the directories
696 window add a new path: 'C:
706 (As a side effect, you get a bunch of Unix utilities that could be useful,
707 such as diff and patch.)
714 This one avoids extracting a bunch of files you may not use, but requires
719 a) Create a directory were to put the tools needed, or use a directory already
727 b) Extract 'bison.exe', 'bison.hairy', 'bison.simple', 'flex.exe', and gawk.exe
728 to such directory WITHOUT preserving the original paths.
729 (If you are using WinZip make certain that 'Use folder names' is not selected)
733 c) Rename bison.exe to '_bison.exe'.
737 d) Create a batch file 'bison.bat' in 'C:
741 ' and add these lines:
761 _bison %1 %2 %3 %4 %5 %6 %7 %8 %9
765 Steps 'c' and 'd' are needed because bison requires by default that the
766 files 'bison.simple' and 'bison.hairy' reside in some weird Unix directory,
767 '/usr/local/share/' I think.
768 So it is necessary to tell bison where those files are located if they
769 are not in such directory.
770 That is the function of the environment variables BISON_SIMPLE and BISON_HAIRY.
774 e) In the Visual C++ IDE click Tools, Options, select the Directory tab,
775 in 'Show directories for:' select 'Executable files', and in the directories
776 window add a new path: 'c:
779 Note that you can use any other path instead of 'c:
781 util', even the path where the Visual C++ tools are, probably: 'C:
785 Microsoft Visual Studio
790 So you don't have to execute step 'e' :)
794 Open 'sdcc.dsw' in Visual Studio, click 'build all', when it finishes copy
795 the executables from sdcc
799 bin, and you can compile using sdcc.
800 \layout Subsubsection
802 Windows Install Using Borland
805 From the sdcc directory, run the command "make -f Makefile.bcc".
806 This should regenerate all the .exe files in the bin directory except for
807 sdcdb.exe (which currently doesn't build under Borland C++).
810 If you modify any source files and need to rebuild, be aware that the dependanci
811 es may not be correctly calculated.
812 The safest option is to delete all .obj files and run the build again.
813 From a Cygwin BASH prompt, this can easily be done with the commmand:
823 ( -name '*.obj' -o -name '*.lib' -o -name '*.rul'
834 or on Windows NT/2000/XP from the command prompt with the commmand:
841 del /s *.obj *.lib *.rul
844 from the sdcc directory.
847 Testing out the SDCC Compiler
850 The first thing you should do after installing your SDCC compiler is to
858 at the prompt, and the program should run and tell you the version.
859 If it doesn't run, or gives a message about not finding sdcc program, then
860 you need to check over your installation.
861 Make sure that the sdcc bin directory is in your executable search path
862 defined by the PATH environment setting (see the Trouble-shooting section
864 Make sure that the sdcc program is in the bin folder, if not perhaps something
865 did not install correctly.
873 is commonly installed as described in section
874 \begin_inset Quotes sld
877 Install and search paths
878 \begin_inset Quotes srd
887 Make sure the compiler works on a very simple example.
888 Type in the following test.c program using your favorite
923 Compile this using the following command:
932 If all goes well, the compiler will generate a test.asm and test.rel file.
933 Congratulations, you've just compiled your first program with SDCC.
934 We used the -c option to tell SDCC not to link the generated code, just
935 to keep things simple for this step.
943 The next step is to try it with the linker.
953 If all goes well the compiler will link with the libraries and produce
954 a test.ihx output file.
959 (no test.ihx, and the linker generates warnings), then the problem is most
960 likely that sdcc cannot find the
964 usr/local/share/sdcc/lib directory
968 (see the Install trouble-shooting section for suggestions).
976 The final test is to ensure sdcc can use the
980 header files and libraries.
981 Edit test.c and change it to the following:
1001 strcpy(str1, "testing");
1010 Compile this by typing
1017 This should generate a test.ihx output file, and it should give no warnings
1018 such as not finding the string.h file.
1019 If it cannot find the string.h file, then the problem is that sdcc cannot
1020 find the /usr/local/share/sdcc/include directory
1024 (see the Install trouble-shooting section for suggestions).
1027 Install Trouble-shooting
1028 \layout Subsubsection
1030 SDCC does not build correctly.
1033 A thing to try is starting from scratch by unpacking the .tgz source package
1034 again in an empty directory.
1042 ./configure 2>&1 | tee configure.log
1056 make 2>&1 | tee make.log
1063 If anything goes wrong, you can review the log files to locate the problem.
1064 Or a relevant part of this can be attached to an email that could be helpful
1065 when requesting help from the mailing list.
1066 \layout Subsubsection
1069 \begin_inset Quotes sld
1073 \begin_inset Quotes srd
1080 \begin_inset Quotes sld
1084 \begin_inset Quotes srd
1087 command is a script that analyzes your system and performs some configuration
1088 to ensure the source package compiles on your system.
1089 It will take a few minutes to run, and will compile a few tests to determine
1090 what compiler features are installed.
1091 \layout Subsubsection
1094 \begin_inset Quotes sld
1098 \begin_inset Quotes srd
1104 This runs the GNU make tool, which automatically compiles all the source
1105 packages into the final installed binary executables.
1106 \layout Subsubsection
1109 \begin_inset Quotes sld
1113 \begin_inset Quotes erd
1119 This will install the compiler, other executables libraries and include
1120 files in to the appropriate directories.
1122 \begin_inset Quotes sld
1125 Install and Search PATHS
1126 \begin_inset Quotes srd
1131 On most systems you will need super-user privilages to do this.
1137 SDCC is not just a compiler, but a collection of tools by various developers.
1138 These include linkers, assemblers, simulators and other components.
1139 Here is a summary of some of the components.
1140 Note that the included simulator and assembler have separate documentation
1141 which you can find in the source package in their respective directories.
1142 As SDCC grows to include support for other processors, other packages from
1143 various developers are included and may have their own sets of documentation.
1147 You might want to look at the files which are installed in <installdir>.
1148 At the time of this writing, we find the following programs for gcc-builds:
1152 In <installdir>/bin:
1155 sdcc - The compiler.
1158 sdcpp - The C preprocessor.
1161 asx8051 - The assembler for 8051 type processors.
1168 as-gbz80 - The Z80 and GameBoy Z80 assemblers.
1171 aslink -The linker for 8051 type processors.
1178 link-gbz80 - The Z80 and GameBoy Z80 linkers.
1181 s51 - The ucSim 8051 simulator.
1184 sdcdb - The source debugger.
1187 packihx - A tool to pack (compress) Intel hex files.
1190 In <installdir>/share/sdcc/include
1196 In <installdir>/share/sdcc/lib
1199 the subdirs src and small, large, z80, gbz80 and ds390 with the precompiled
1203 In <installdir>/share/sdcc/doc
1209 As development for other processors proceeds, this list will expand to include
1210 executables to support processors like AVR, PIC, etc.
1211 \layout Subsubsection
1216 This is the actual compiler, it in turn uses the c-preprocessor and invokes
1217 the assembler and linkage editor.
1218 \layout Subsubsection
1220 sdcpp - The C-Preprocessor
1223 The preprocessor is a modified version of the GNU preprocessor.
1224 The C preprocessor is used to pull in #include sources, process #ifdef
1225 statements, #defines and so on.
1226 \layout Subsubsection
1228 asx8051, as-z80, as-gbz80, aslink, link-z80, link-gbz80 - The Assemblers
1232 This is retargettable assembler & linkage editor, it was developed by Alan
1234 John Hartman created the version for 8051, and I (Sandeep) have made some
1235 enhancements and bug fixes for it to work properly with the SDCC.
1236 \layout Subsubsection
1241 S51 is a freeware, opensource simulator developed by Daniel Drotos (
1242 \begin_inset LatexCommand \url{mailto:drdani@mazsola.iit.uni-miskolc.hu}
1247 The simulator is built as part of the build process.
1248 For more information visit Daniel's website at:
1249 \begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
1254 It currently support the core mcs51, the Dallas DS80C390 and the Philips
1256 \layout Subsubsection
1258 sdcdb - Source Level Debugger
1264 <todo: is this thing still alive?>
1271 Sdcdb is the companion source level debugger.
1272 The current version of the debugger uses Daniel's Simulator S51, but can
1273 be easily changed to use other simulators.
1280 \layout Subsubsection
1282 Single Source File Projects
1285 For single source file 8051 projects the process is very simple.
1286 Compile your programs with the following command
1289 "sdcc sourcefile.c".
1293 This will compile, assemble and link your source file.
1294 Output files are as follows
1298 sourcefile.asm - Assembler source file created by the compiler
1300 sourcefile.lst - Assembler listing file created by the Assembler
1302 sourcefile.rst - Assembler listing file updated with linkedit information,
1303 created by linkage editor
1305 sourcefile.sym - symbol listing for the sourcefile, created by the assembler
1307 sourcefile.rel - Object file created by the assembler, input to Linkage editor
1309 sourcefile.map - The memory map for the load module, created by the Linker
1311 sourcefile.ihx - The load module in Intel hex format (you can select the
1312 Motorola S19 format with ---out-fmt-s19)
1314 sourcefile.cdb - An optional file (with ---debug) containing debug information
1316 sourcefile.dump* - Dump file to debug the compiler it self (with ---dumpall)
1318 \begin_inset Quotes sld
1321 Anatomy of the compiler
1322 \begin_inset Quotes srd
1326 \layout Subsubsection
1328 Projects with Multiple Source Files
1331 SDCC can compile only ONE file at a time.
1332 Let us for example assume that you have a project containing the following
1337 foo1.c (contains some functions)
1339 foo2.c (contains some more functions)
1341 foomain.c (contains more functions and the function main)
1349 The first two files will need to be compiled separately with the commands:
1381 Then compile the source file containing the
1385 function and link the files together with the following command:
1393 foomain.c\SpecialChar ~
1394 foo1.rel\SpecialChar ~
1406 can be separately compiled as well:
1417 sdcc foomain.rel foo1.rel foo2.rel
1424 The file containing the
1439 file specified in the command line, since the linkage editor processes
1440 file in the order they are presented to it.
1441 \layout Subsubsection
1443 Projects with Additional Libraries
1446 Some reusable routines may be compiled into a library, see the documentation
1447 for the assembler and linkage editor (which are in <installdir>/share/sdcc/doc)
1453 Libraries created in this manner can be included in the command line.
1454 Make sure you include the -L <library-path> option to tell the linker where
1455 to look for these files if they are not in the current directory.
1456 Here is an example, assuming you have the source file
1468 (if that is not the same as your current project):
1475 sdcc foomain.c foolib.lib -L mylib
1486 must be an absolute path name.
1490 The most efficient way to use libraries is to keep seperate modules in seperate
1492 The lib file now should name all the modules.rel files.
1493 For an example see the standard library file
1497 in the directory <installdir>/share/lib/small.
1500 Command Line Options
1501 \layout Subsubsection
1503 Processor Selection Options
1505 \labelwidthstring 00.00.0000
1511 Generate code for the MCS51 (8051) family of processors.
1512 This is the default processor target.
1514 \labelwidthstring 00.00.0000
1520 Generate code for the DS80C390 processor.
1522 \labelwidthstring 00.00.0000
1528 Generate code for the Z80 family of processors.
1530 \labelwidthstring 00.00.0000
1536 Generate code for the GameBoy Z80 processor.
1538 \labelwidthstring 00.00.0000
1544 Generate code for the Atmel AVR processor (In development, not complete).
1546 \labelwidthstring 00.00.0000
1552 Generate code for the PIC 14-bit processors (In development, not complete).
1554 \labelwidthstring 00.00.0000
1560 Generate code for the Toshiba TLCS-900H processor (In development, not
1563 \labelwidthstring 00.00.0000
1569 Generate code for the Philips XA51 processor (In development, not complete).
1570 \layout Subsubsection
1572 Preprocessor Options
1574 \labelwidthstring 00.00.0000
1580 The additional location where the pre processor will look for <..h> or
1581 \begin_inset Quotes eld
1585 \begin_inset Quotes erd
1590 \labelwidthstring 00.00.0000
1596 Command line definition of macros.
1597 Passed to the pre processor.
1599 \labelwidthstring 00.00.0000
1605 Tell the preprocessor to output a rule suitable for make describing the
1606 dependencies of each object file.
1607 For each source file, the preprocessor outputs one make-rule whose target
1608 is the object file name for that source file and whose dependencies are
1609 all the files `#include'd in it.
1610 This rule may be a single line or may be continued with `
1612 '-newline if it is long.
1613 The list of rules is printed on standard output instead of the preprocessed
1617 \labelwidthstring 00.00.0000
1623 Tell the preprocessor not to discard comments.
1624 Used with the `-E' option.
1626 \labelwidthstring 00.00.0000
1637 Like `-M' but the output mentions only the user header files included with
1639 \begin_inset Quotes eld
1643 System header files included with `#include <file>' are omitted.
1645 \labelwidthstring 00.00.0000
1651 Assert the answer answer for question, in case it is tested with a preprocessor
1652 conditional such as `#if #question(answer)'.
1653 `-A-' disables the standard assertions that normally describe the target
1656 \labelwidthstring 00.00.0000
1662 (answer) Assert the answer answer for question, in case it is tested with
1663 a preprocessor conditional such as `#if #question(answer)'.
1664 `-A-' disables the standard assertions that normally describe the target
1667 \labelwidthstring 00.00.0000
1673 Undefine macro macro.
1674 `-U' options are evaluated after all `-D' options, but before any `-include'
1675 and `-imacros' options.
1677 \labelwidthstring 00.00.0000
1683 Tell the preprocessor to output only a list of the macro definitions that
1684 are in effect at the end of preprocessing.
1685 Used with the `-E' option.
1687 \labelwidthstring 00.00.0000
1693 Tell the preprocessor to pass all macro definitions into the output, in
1694 their proper sequence in the rest of the output.
1696 \labelwidthstring 00.00.0000
1707 Like `-dD' except that the macro arguments and contents are omitted.
1708 Only `#define name' is included in the output.
1709 \layout Subsubsection
1713 \labelwidthstring 00.00.0000
1720 the output path resp.
1721 file where everything will be placed
1723 \labelwidthstring 00.00.0000
1733 <absolute path to additional libraries> This option is passed to the linkage
1734 editor's additional libraries search path.
1735 The path name must be absolute.
1736 Additional library files may be specified in the command line.
1737 See section Compiling programs for more details.
1739 \labelwidthstring 00.00.0000
1745 <Value> The start location of the external ram, default value is 0.
1746 The value entered can be in Hexadecimal or Decimal format, e.g.: ---xram-loc
1747 0x8000 or ---xram-loc 32768.
1749 \labelwidthstring 00.00.0000
1755 <Value> The start location of the code segment, default value 0.
1756 Note when this option is used the interrupt vector table is also relocated
1757 to the given address.
1758 The value entered can be in Hexadecimal or Decimal format, e.g.: ---code-loc
1759 0x8000 or ---code-loc 32768.
1761 \labelwidthstring 00.00.0000
1767 <Value> By default the stack is placed after the data segment.
1768 Using this option the stack can be placed anywhere in the internal memory
1770 The value entered can be in Hexadecimal or Decimal format, e.g.
1771 ---stack-loc 0x20 or ---stack-loc 32.
1772 Since the sp register is incremented before a push or call, the initial
1773 sp will be set to one byte prior the provided value.
1774 The provided value should not overlap any other memory areas such as used
1775 register banks or the data segment and with enough space for the current
1778 \labelwidthstring 00.00.0000
1784 <Value> The start location of the internal ram data segment.
1785 The value entered can be in Hexadecimal or Decimal format, eg.
1786 ---data-loc 0x20 or ---data-loc 32.
1787 (By default, the start location of the internal ram data segment is set
1788 as low as possible in memory, taking into account the used register banks
1789 and the bit segment at address 0x20.
1790 For example if register banks 0 and 1 are used without bit variables, the
1791 data segment will be set, if ---data-loc is not used, to location 0x10.)
1793 \labelwidthstring 00.00.0000
1799 <Value> The start location of the indirectly addressable internal ram, default
1801 The value entered can be in Hexadecimal or Decimal format, eg.
1802 ---idata-loc 0x88 or ---idata-loc 136.
1804 \labelwidthstring 00.00.0000
1813 The linker output (final object code) is in Intel Hex format.
1814 (This is the default option).
1816 \labelwidthstring 00.00.0000
1825 The linker output (final object code) is in Motorola S19 format.
1826 \layout Subsubsection
1830 \labelwidthstring 00.00.0000
1836 Generate code for Large model programs see section Memory Models for more
1838 If this option is used all source files in the project should be compiled
1840 In addition the standard library routines are compiled with small model,
1841 they will need to be recompiled.
1843 \labelwidthstring 00.00.0000
1854 Generate code for Small Model programs see section Memory Models for more
1856 This is the default model.
1857 \layout Subsubsection
1861 \labelwidthstring 00.00.0000
1872 Generate 24-bit flat mode code.
1873 This is the one and only that the ds390 code generator supports right now
1874 and is default when using
1879 See section Memory Models for more details.
1881 \labelwidthstring 00.00.0000
1887 Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
1888 This is the one and only that the ds390 code generator supports right now
1889 and is default when using
1894 In this mode, the stack is located in the lower 1K of the internal RAM,
1895 which is mapped to 0x400000.
1896 Note that the support is incomplete, since it still uses a single byte
1897 as the stack pointer.
1898 This means that only the lower 256 bytes of the potential 1K stack space
1899 will actually be used.
1900 However, this does allow you to reclaim the precious 256 bytes of low RAM
1901 for use for the DATA and IDATA segments.
1902 The compiler will not generate any code to put the processor into 10 bit
1904 It is important to ensure that the processor is in this mode before calling
1905 any re-entrant functions compiled with this option.
1906 In principle, this should work with the
1910 option, but that has not been tested.
1911 It is incompatible with the
1916 It also only makes sense if the processor is in 24 bit contiguous addressing
1919 ---model-flat24 option
1922 \layout Subsubsection
1924 Optimization Options
1926 \labelwidthstring 00.00.0000
1932 Will not do global subexpression elimination, this option may be used when
1933 the compiler creates undesirably large stack/data spaces to store compiler
1935 A warning message will be generated when this happens and the compiler
1936 will indicate the number of extra bytes it allocated.
1937 It recommended that this option NOT be used, #pragma\SpecialChar ~
1939 to turn off global subexpression elimination for a given function only.
1941 \labelwidthstring 00.00.0000
1947 Will not do loop invariant optimizations, this may be turned off for reasons
1948 explained for the previous option.
1949 For more details of loop optimizations performed see section Loop Invariants.It
1950 recommended that this option NOT be used, #pragma\SpecialChar ~
1951 NOINVARIANT can be used
1952 to turn off invariant optimizations for a given function only.
1954 \labelwidthstring 00.00.0000
1960 Will not do loop induction optimizations, see section strength reduction
1961 for more details.It is recommended that this option is NOT used, #pragma\SpecialChar ~
1963 ION can be used to turn off induction optimizations for a given function
1966 \labelwidthstring 00.00.0000
1977 Will not generate boundary condition check when switch statements are implement
1978 ed using jump-tables.
1979 See section Switch Statements for more details.
1980 It is recommended that this option is NOT used, #pragma\SpecialChar ~
1982 used to turn off boundary checking for jump tables for a given function
1985 \labelwidthstring 00.00.0000
1994 Will not do loop reversal optimization.
1996 \labelwidthstring 00.00.0000
2002 This will disable the memcpy of initialized data in far space from code
2004 \layout Subsubsection
2008 \labelwidthstring 00.00.0000
2015 will compile and assemble the source, but will not call the linkage editor.
2017 \labelwidthstring 00.00.0000
2023 Run only the C preprocessor.
2024 Preprocess all the C source files specified and output the results to standard
2027 \labelwidthstring 00.00.0000
2038 All functions in the source file will be compiled as
2043 the parameters and local variables will be allocated on the stack.
2044 see section Parameters and Local Variables for more details.
2045 If this option is used all source files in the project should be compiled
2049 \labelwidthstring 00.00.0000
2055 Uses a pseudo stack in the first 256 bytes in the external ram for allocating
2056 variables and passing parameters.
2057 See section on external stack for more details.
2059 \labelwidthstring 00.00.0000
2063 ---callee-saves function1[,function2][,function3]....
2066 The compiler by default uses a caller saves convention for register saving
2067 across function calls, however this can cause unneccessary register pushing
2068 & popping when calling small functions from larger functions.
2069 This option can be used to switch the register saving convention for the
2070 function names specified.
2071 The compiler will not save registers when calling these functions, no extra
2072 code will be generated at the entry & exit for these functions to save
2073 & restore the registers used by these functions, this can SUBSTANTIALLY
2074 reduce code & improve run time performance of the generated code.
2075 In the future the compiler (with interprocedural analysis) will be able
2076 to determine the appropriate scheme to use for each function call.
2077 DO NOT use this option for built-in functions such as _muluint..., if this
2078 option is used for a library function the appropriate library function
2079 needs to be recompiled with the same option.
2080 If the project consists of multiple source files then all the source file
2081 should be compiled with the same ---callee-saves option string.
2082 Also see #pragma\SpecialChar ~
2085 \labelwidthstring 00.00.0000
2094 When this option is used the compiler will generate debug information, that
2095 can be used with the SDCDB.
2096 The debug information is collected in a file with .cdb extension.
2097 For more information see documentation for SDCDB.
2099 \labelwidthstring 00.00.0000
2105 <filename> This option can be used to use additional rules to be used by
2106 the peep hole optimizer.
2107 See section Peep Hole optimizations for details on how to write these rules.
2109 \labelwidthstring 00.00.0000
2120 Stop after the stage of compilation proper; do not assemble.
2121 The output is an assembler code file for the input file specified.
2123 \labelwidthstring 00.00.0000
2127 -Wa_asmOption[,asmOption]
2130 Pass the asmOption to the assembler.
2132 \labelwidthstring 00.00.0000
2136 -Wl_linkOption[,linkOption]
2139 Pass the linkOption to the linker.
2141 \labelwidthstring 00.00.0000
2150 Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
2151 Note by default these libraries are compiled as non-reentrant.
2152 See section Installation for more details.
2154 \labelwidthstring 00.00.0000
2163 This option will cause the compiler to generate an information message for
2164 each function in the source file.
2165 The message contains some
2169 information about the function.
2170 The number of edges and nodes the compiler detected in the control flow
2171 graph of the function, and most importantly the
2173 cyclomatic complexity
2175 see section on Cyclomatic Complexity for more details.
2177 \labelwidthstring 00.00.0000
2186 Floating point library is compiled as reentrant.See section Installation
2189 \labelwidthstring 00.00.0000
2195 The compiler will not overlay parameters and local variables of any function,
2196 see section Parameters and local variables for more details.
2198 \labelwidthstring 00.00.0000
2204 This option can be used when the code generated is called by a monitor
2206 The compiler will generate a 'ret' upon return from the 'main' function.
2207 The default option is to lock up i.e.
2210 \labelwidthstring 00.00.0000
2216 Disable peep-hole optimization.
2218 \labelwidthstring 00.00.0000
2224 Pass the inline assembler code through the peep hole optimizer.
2225 This can cause unexpected changes to inline assembler code, please go through
2226 the peephole optimizer rules defined in the source file tree '<target>/peeph.def
2227 ' before using this option.
2229 \labelwidthstring 00.00.0000
2235 <Value> Causes the linker to check if the internal ram usage is within limits
2238 \labelwidthstring 00.00.0000
2244 <Value> Causes the linker to check if the external ram usage is within limits
2247 \labelwidthstring 00.00.0000
2253 <Value> Causes the linker to check if the code usage is within limits of
2256 \labelwidthstring 00.00.0000
2262 This will prevent the compiler from passing on the default include path
2263 to the preprocessor.
2265 \labelwidthstring 00.00.0000
2271 This will prevent the compiler from passing on the default library path
2274 \labelwidthstring 00.00.0000
2280 Shows the various actions the compiler is performing.
2282 \labelwidthstring 00.00.0000
2288 Shows the actual commands the compiler is executing.
2289 \layout Subsubsection
2291 Intermediate Dump Options
2294 The following options are provided for the purpose of retargetting and debugging
2296 These provided a means to dump the intermediate code (iCode) generated
2297 by the compiler in human readable form at various stages of the compilation
2301 \labelwidthstring 00.00.0000
2307 This option will cause the compiler to dump the intermediate code into
2310 <source filename>.dumpraw
2312 just after the intermediate code has been generated for a function, i.e.
2313 before any optimizations are done.
2314 The basic blocks at this stage ordered in the depth first number, so they
2315 may not be in sequence of execution.
2317 \labelwidthstring 00.00.0000
2323 Will create a dump of iCode's, after global subexpression elimination,
2326 <source filename>.dumpgcse.
2328 \labelwidthstring 00.00.0000
2334 Will create a dump of iCode's, after deadcode elimination, into a file
2337 <source filename>.dumpdeadcode.
2339 \labelwidthstring 00.00.0000
2348 Will create a dump of iCode's, after loop optimizations, into a file named
2351 <source filename>.dumploop.
2353 \labelwidthstring 00.00.0000
2362 Will create a dump of iCode's, after live range analysis, into a file named
2365 <source filename>.dumprange.
2367 \labelwidthstring 00.00.0000
2373 Will dump the life ranges for all symbols.
2375 \labelwidthstring 00.00.0000
2384 Will create a dump of iCode's, after register assignment, into a file named
2387 <source filename>.dumprassgn.
2389 \labelwidthstring 00.00.0000
2395 Will create a dump of the live ranges of iTemp's
2397 \labelwidthstring 00.00.0000
2408 Will cause all the above mentioned dumps to be created.
2411 MCS51/DS390 Storage Class Language Extensions
2414 In addition to the ANSI storage classes SDCC allows the following MCS51
2415 specific storage classes.
2416 \layout Subsubsection
2421 Variables declared with this storage class will be placed in the extern
2427 storage class for Large Memory model, e.g.:
2433 xdata unsigned char xduc;
2434 \layout Subsubsection
2443 storage class for Small Memory model.
2444 Variables declared with this storage class will be allocated in the internal
2452 \layout Subsubsection
2457 Variables declared with this storage class will be allocated into the indirectly
2458 addressable portion of the internal ram of a 8051, e.g.:
2465 \layout Subsubsection
2470 This is a data-type and a storage class specifier.
2471 When a variable is declared as a bit, it is allocated into the bit addressable
2472 memory of 8051, e.g.:
2479 \layout Subsubsection
2484 Like the bit keyword,
2488 signifies both a data-type and storage class, they are used to describe
2489 the special function registers and special bit variables of a 8051, eg:
2495 sfr at 0x80 P0; /* special function register P0 at location 0x80 */
2497 sbit at 0xd7 CY; /* CY (Carry Flag) */
2503 SDCC allows (via language extensions) pointers to explicitly point to any
2504 of the memory spaces of the 8051.
2505 In addition to the explicit pointers, the compiler uses (by default) generic
2506 pointers which can be used to point to any of the memory spaces.
2510 Pointer declaration examples:
2519 /* pointer physically in xternal ram pointing to object in internal ram
2522 data unsigned char * xdata p;
2526 /* pointer physically in code rom pointing to data in xdata space */
2528 xdata unsigned char * code p;
2532 /* pointer physically in code space pointing to data in code space */
2534 code unsigned char * code p;
2538 /* the folowing is a generic pointer physically located in xdata space */
2549 Well you get the idea.
2554 All unqualified pointers are treated as 3-byte (4-byte for the ds390)
2567 The highest order byte of the
2571 pointers contains the data space information.
2572 Assembler support routines are called whenever data is stored or retrieved
2578 These are useful for developing reusable library routines.
2579 Explicitly specifying the pointer type will generate the most efficient
2583 Parameters & Local Variables
2586 Automatic (local) variables and parameters to functions can either be placed
2587 on the stack or in data-space.
2588 The default action of the compiler is to place these variables in the internal
2589 RAM (for small model) or external RAM (for large model).
2590 This in fact makes them
2594 so by default functions are non-reentrant.
2598 They can be placed on the stack either by using the
2602 option or by using the
2606 keyword in the function declaration, e.g.:
2615 unsigned char foo(char i) reentrant
2628 Since stack space on 8051 is limited, the
2636 option should be used sparingly.
2637 Note that the reentrant keyword just means that the parameters & local
2638 variables will be allocated to the stack, it
2642 mean that the function is register bank independent.
2646 Local variables can be assigned storage classes and absolute addresses,
2653 unsigned char foo() {
2659 xdata unsigned char i;
2671 data at 0x31 unsiged char j;
2686 In the above example the variable
2690 will be allocated in the external ram,
2694 in bit addressable space and
2703 or when a function is declared as
2707 this should only be done for static variables.
2710 Parameters however are not allowed any storage class, (storage classes for
2711 parameters will be ignored), their allocation is governed by the memory
2712 model in use, and the reentrancy options.
2718 For non-reentrant functions SDCC will try to reduce internal ram space usage
2719 by overlaying parameters and local variables of a function (if possible).
2720 Parameters and local variables of a function will be allocated to an overlayabl
2721 e segment if the function has
2723 no other function calls and the function is non-reentrant and the memory
2727 If an explicit storage class is specified for a local variable, it will
2731 Note that the compiler (not the linkage editor) makes the decision for overlayin
2733 Functions that are called from an interrupt service routine should be preceded
2734 by a #pragma\SpecialChar ~
2735 NOOVERLAY if they are not reentrant.
2738 Also note that the compiler does not do any processing of inline assembler
2739 code, so the compiler might incorrectly assign local variables and parameters
2740 of a function into the overlay segment if the inline assembler code calls
2741 other c-functions that might use the overlay.
2742 In that case the #pragma\SpecialChar ~
2743 NOOVERLAY should be used.
2746 Parameters and Local variables of functions that contain 16 or 32 bit multiplica
2747 tion or division will NOT be overlayed since these are implemented using
2748 external functions, e.g.:
2758 void set_error(unsigned char errcd)
2774 void some_isr () interrupt 2 using 1
2803 In the above example the parameter
2811 would be assigned to the overlayable segment if the #pragma\SpecialChar ~
2813 not present, this could cause unpredictable runtime behavior when called
2815 The #pragma\SpecialChar ~
2816 NOOVERLAY ensures that the parameters and local variables for
2817 the function are NOT overlayed.
2820 Interrupt Service Routines
2823 SDCC allows interrupt service routines to be coded in C, with some extended
2830 void timer_isr (void) interrupt 2 using 1
2843 The number following the
2847 keyword is the interrupt number this routine will service.
2848 The compiler will insert a call to this routine in the interrupt vector
2849 table for the interrupt number specified.
2854 keyword is used to tell the compiler to use the specified register bank
2855 (8051 specific) when generating code for this function.
2856 Note that when some function is called from an interrupt service routine
2857 it should be preceded by a #pragma\SpecialChar ~
2858 NOOVERLAY if it is not reentrant.
2859 A special note here, int (16 bit) and long (32 bit) integer division, multiplic
2860 ation & modulus operations are implemented using external support routines
2861 developed in ANSI-C, if an interrupt service routine needs to do any of
2862 these operations then the support routines (as mentioned in a following
2863 section) will have to be recompiled using the
2867 option and the source file will need to be compiled using the
2874 If you have multiple source files in your project, interrupt service routines
2875 can be present in any of them, but a prototype of the isr MUST be present
2876 or included in the file that contains the function
2883 Interrupt Numbers and the corresponding address & descriptions for the Standard
2884 8051 are listed below.
2885 SDCC will automatically adjust the interrupt vector table to the maximum
2886 interrupt number specified.
2892 \begin_inset Tabular
2893 <lyxtabular version="3" rows="6" columns="3">
2895 <column alignment="center" valignment="top" leftline="true" width="0(null)">
2896 <column alignment="center" valignment="top" leftline="true" width="0(null)">
2897 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0(null)">
2898 <row topline="true" bottomline="true">
2899 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2907 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2915 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2924 <row topline="true">
2925 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2933 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2941 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2950 <row topline="true">
2951 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2959 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2967 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2976 <row topline="true">
2977 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2985 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2993 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3002 <row topline="true">
3003 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3011 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3019 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3028 <row topline="true" bottomline="true">
3029 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3037 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
3045 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
3062 If the interrupt service routine is defined without
3066 a register bank or with register bank 0 (using 0), the compiler will save
3067 the registers used by itself on the stack upon entry and restore them at
3068 exit, however if such an interrupt service routine calls another function
3069 then the entire register bank will be saved on the stack.
3070 This scheme may be advantageous for small interrupt service routines which
3071 have low register usage.
3074 If the interrupt service routine is defined to be using a specific register
3079 are save and restored, if such an interrupt service routine calls another
3080 function (using another register bank) then the entire register bank of
3081 the called function will be saved on the stack.
3082 This scheme is recommended for larger interrupt service routines.
3085 Calling other functions from an interrupt service routine is not recommended,
3086 avoid it if possible.
3090 Also see the _naked modifier.
3098 <TODO: this isn't implemented at all!>
3104 A special keyword may be associated with a function declaring it as
3109 SDCC will generate code to disable all interrupts upon entry to a critical
3110 function and enable them back before returning.
3111 Note that nesting critical functions may cause unpredictable results.
3136 The critical attribute maybe used with other attributes like
3144 A special keyword may be associated with a function declaring it as
3153 function modifier attribute prevents the compiler from generating prologue
3154 and epilogue code for that function.
3155 This means that the user is entirely responsible for such things as saving
3156 any registers that may need to be preserved, selecting the proper register
3157 bank, generating the
3161 instruction at the end, etc.
3162 Practically, this means that the contents of the function must be written
3163 in inline assembler.
3164 This is particularly useful for interrupt functions, which can have a large
3165 (and often unnecessary) prologue/epilogue.
3166 For example, compare the code generated by these two functions:
3172 data unsigned char counter;
3174 void simpleInterrupt(void) interrupt 1
3188 void nakedInterrupt(void) interrupt 2 _naked
3221 ; MUST explicitly include ret in _naked function.
3235 For an 8051 target, the generated simpleInterrupt looks like:
3380 whereas nakedInterrupt looks like:
3405 ; MUST explicitly include ret(i) in _naked function.
3411 While there is nothing preventing you from writing C code inside a _naked
3412 function, there are many ways to shoot yourself in the foot doing this,
3413 and it is recommended that you stick to inline assembler.
3416 Functions using private banks
3423 attribute (which tells the compiler to use a register bank other than the
3424 default bank zero) should only be applied to
3428 functions (see note 1 below).
3429 This will in most circumstances make the generated ISR code more efficient
3430 since it will not have to save registers on the stack.
3437 attribute will have no effect on the generated code for a
3441 function (but may occasionally be useful anyway
3447 possible exception: if a function is called ONLY from 'interrupt' functions
3448 using a particular bank, it can be declared with the same 'using' attribute
3449 as the calling 'interrupt' functions.
3450 For instance, if you have several ISRs using bank one, and all of them
3451 call memcpy(), it might make sense to create a specialized version of memcpy()
3452 'using 1', since this would prevent the ISR from having to save bank zero
3453 to the stack on entry and switch to bank zero before calling the function
3460 (pending: I don't think this has been done yet)
3467 function using a non-zero bank will assume that it can trash that register
3468 bank, and will not save it.
3469 Since high-priority interrupts can interrupt low-priority ones on the 8051
3470 and friends, this means that if a high-priority ISR
3474 a particular bank occurs while processing a low-priority ISR
3478 the same bank, terrible and bad things can happen.
3479 To prevent this, no single register bank should be
3483 by both a high priority and a low priority ISR.
3484 This is probably most easily done by having all high priority ISRs use
3485 one bank and all low priority ISRs use another.
3486 If you have an ISR which can change priority at runtime, you're on your
3487 own: I suggest using the default bank zero and taking the small performance
3491 It is most efficient if your ISR calls no other functions.
3492 If your ISR must call other functions, it is most efficient if those functions
3493 use the same bank as the ISR (see note 1 below); the next best is if the
3494 called functions use bank zero.
3495 It is very inefficient to call a function using a different, non-zero bank
3503 Data items can be assigned an absolute address with the
3507 keyword, in addition to a storage class, e.g.:
3513 xdata at 0x8000 unsigned char PORTA_8255 ;
3519 In the above example the PORTA_8255 will be allocated to the location 0x8000
3520 of the external ram.
3521 Note that this feature is provided to give the programmer access to
3525 devices attached to the controller.
3526 The compiler does not actually reserve any space for variables declared
3527 in this way (they are implemented with an equate in the assembler).
3528 Thus it is left to the programmer to make sure there are no overlaps with
3529 other variables that are declared without the absolute address.
3530 The assembler listing file (.lst) and the linker output files (.rst) and
3531 (.map) are a good places to look for such overlaps.
3535 Absolute address can be specified for variables in all storage classes,
3548 The above example will allocate the variable at offset 0x02 in the bit-addressab
3550 There is no real advantage to assigning absolute addresses to variables
3551 in this manner, unless you want strict control over all the variables allocated.
3557 The compiler inserts a call to the C routine
3559 _sdcc__external__startup()
3564 at the start of the CODE area.
3565 This routine is in the runtime library.
3566 By default this routine returns 0, if this routine returns a non-zero value,
3567 the static & global variable initialization will be skipped and the function
3568 main will be invoked Other wise static & global variables will be initialized
3569 before the function main is invoked.
3572 _sdcc__external__startup()
3574 routine to your program to override the default if you need to setup hardware
3575 or perform some other critical operation prior to static & global variable
3579 Inline Assembler Code
3582 SDCC allows the use of in-line assembler with a few restriction as regards
3584 All labels defined within inline assembler code
3592 where nnnn is a number less than 100 (which implies a limit of utmost 100
3593 inline assembler labels
3601 It is strongly recommended that each assembly instruction (including labels)
3602 be placed in a separate line (as the example shows).
3607 command line option is used, the inline assembler code will be passed through
3608 the peephole optimizer.
3609 This might cause some unexpected changes in the inline assembler code.
3610 Please go throught the peephole optimizer rules defined in file
3614 carefully before using this option.
3654 The inline assembler code can contain any valid code understood by the assembler
3655 , this includes any assembler directives and comment lines.
3656 The compiler does not do any validation of the code within the
3666 Inline assembler code cannot reference any C-Labels, however it can reference
3667 labels defined by the inline assembler, e.g.:
3693 ; some assembler code
3713 /* some more c code */
3715 clabel:\SpecialChar ~
3717 /* inline assembler cannot reference this label */
3729 $0003: ;label (can be reference by inline assembler only)
3741 /* some more c code */
3749 In other words inline assembly code can access labels defined in inline
3750 assembly within the scope of the funtion.
3754 The same goes the other way, ie.
3755 labels defines in inline assembly CANNOT be accessed by C statements.
3758 int(16 bit) and long (32 bit) Support
3761 For signed & unsigned int (16 bit) and long (32 bit) variables, division,
3762 multiplication and modulus operations are implemented by support routines.
3763 These support routines are all developed in ANSI-C to facilitate porting
3764 to other MCUs, although some model specific assembler optimations are used.
3765 The following files contain the described routine, all of them can be found
3766 in <installdir>/share/sdcc/lib.
3772 <pending: tabularise this>
3778 _mulsint.c - signed 16 bit multiplication (calls _muluint)
3780 _muluint.c - unsigned 16 bit multiplication
3782 _divsint.c - signed 16 bit division (calls _divuint)
3784 _divuint.c - unsigned 16 bit division
3786 _modsint.c - signed 16 bit modulus (call _moduint)
3788 _moduint.c - unsigned 16 bit modulus
3790 _mulslong.c - signed 32 bit multiplication (calls _mululong)
3792 _mululong.c - unsigned32 bit multiplication
3794 _divslong.c - signed 32 division (calls _divulong)
3796 _divulong.c - unsigned 32 division
3798 _modslong.c - signed 32 bit modulus (calls _modulong)
3800 _modulong.c - unsigned 32 bit modulus
3808 Since they are compiled as
3812 , interrupt service routines should not do any of the above operations.
3813 If this is unavoidable then the above routines will need to be compiled
3818 option, after which the source program will have to be compiled with
3825 Floating Point Support
3828 SDCC supports IEEE (single precision 4bytes) floating point numbers.The floating
3829 point support routines are derived from gcc's floatlib.c and consists of
3830 the following routines:
3836 <pending: tabularise this>
3842 _fsadd.c - add floating point numbers
3844 _fssub.c - subtract floating point numbers
3846 _fsdiv.c - divide floating point numbers
3848 _fsmul.c - multiply floating point numbers
3850 _fs2uchar.c - convert floating point to unsigned char
3852 _fs2char.c - convert floating point to signed char
3854 _fs2uint.c - convert floating point to unsigned int
3856 _fs2int.c - convert floating point to signed int
3858 _fs2ulong.c - convert floating point to unsigned long
3860 _fs2long.c - convert floating point to signed long
3862 _uchar2fs.c - convert unsigned char to floating point
3864 _char2fs.c - convert char to floating point number
3866 _uint2fs.c - convert unsigned int to floating point
3868 _int2fs.c - convert int to floating point numbers
3870 _ulong2fs.c - convert unsigned long to floating point number
3872 _long2fs.c - convert long to floating point number
3880 Note if all these routines are used simultaneously the data space might
3882 For serious floating point usage it is strongly recommended that the large
3889 SDCC allows two memory models for MCS51 code, small and large.
3890 Modules compiled with different memory models should
3894 be combined together or the results would be unpredictable.
3895 The library routines supplied with the compiler are compiled as both small
3897 The compiled library modules are contained in seperate directories as small
3898 and large so that you can link to either set.
3902 When the large model is used all variables declared without a storage class
3903 will be allocated into the external ram, this includes all parameters and
3904 local variables (for non-reentrant functions).
3905 When the small model is used variables without storage class are allocated
3906 in the internal ram.
3909 Judicious usage of the processor specific storage classes and the 'reentrant'
3910 function type will yield much more efficient code, than using the large
3912 Several optimizations are disabled when the program is compiled using the
3913 large model, it is therefore strongly recommdended that the small model
3914 be used unless absolutely required.
3920 The only model supported is Flat 24.
3921 This generates code for the 24 bit contiguous addressing mode of the Dallas
3923 In this mode, up to four meg of external RAM or code space can be directly
3925 See the data sheets at www.dalsemi.com for further information on this part.
3929 In older versions of the compiler, this option was used with the MCS51 code
3935 Now, however, the '390 has it's own code generator, selected by the
3944 Note that the compiler does not generate any code to place the processor
3945 into 24 bitmode (although
3949 in the ds390 libraries will do that for you).
3954 , the boot loader or similar code must ensure that the processor is in 24
3955 bit contiguous addressing mode before calling the SDCC startup code.
3963 option, variables will by default be placed into the XDATA segment.
3968 Segments may be placed anywhere in the 4 meg address space using the usual
3970 Note that if any segments are located above 64K, the -r flag must be passed
3971 to the linker to generate the proper segment relocations, and the Intel
3972 HEX output format must be used.
3973 The -r flag can be passed to the linker by using the option
3977 on the sdcc command line.
3978 However, currently the linker can not handle code segments > 64k.
3981 Defines Created by the Compiler
3984 The compiler creates the following #defines.
3987 SDCC - this Symbol is always defined.
3990 SDCC_mcs51 or SDCC_ds390 or SDCC_z80, etc - depending on the model used
3994 __mcs51 or __ds390 or __z80, etc - depending on the model used (e.g.
3998 SDCC_STACK_AUTO - this symbol is defined when
4005 SDCC_MODEL_SMALL - when
4012 SDCC_MODEL_LARGE - when
4019 SDCC_USE_XSTACK - when
4026 SDCC_STACK_TENBIT - when
4033 SDCC_MODEL_FLAT24 - when
4046 SDCC performs a host of standard optimizations in addition to some MCU specific
4049 \layout Subsubsection
4051 Sub-expression Elimination
4054 The compiler does local and global common subexpression elimination, e.g.:
4069 will be translated to
4085 Some subexpressions are not as obvious as the above example, e.g.:
4099 In this case the address arithmetic a->b[i] will be computed only once;
4100 the equivalent code in C would be.
4116 The compiler will try to keep these temporary variables in registers.
4117 \layout Subsubsection
4119 Dead-Code Elimination
4134 i = 1; \SpecialChar ~
4139 global = 1;\SpecialChar ~
4152 global = 3;\SpecialChar ~
4167 int global; void f ()
4180 \layout Subsubsection
4241 Note: the dead stores created by this copy propagation will be eliminated
4242 by dead-code elimination.
4243 \layout Subsubsection
4248 Two types of loop optimizations are done by SDCC loop invariant lifting
4249 and strength reduction of loop induction variables.
4250 In addition to the strength reduction the optimizer marks the induction
4251 variables and the register allocator tries to keep the induction variables
4252 in registers for the duration of the loop.
4253 Because of this preference of the register allocator, loop induction optimizati
4254 on causes an increase in register pressure, which may cause unwanted spilling
4255 of other temporary variables into the stack / data space.
4256 The compiler will generate a warning message when it is forced to allocate
4257 extra space either on the stack or data space.
4258 If this extra space allocation is undesirable then induction optimization
4259 can be eliminated either for the entire source file (with ---noinduction
4260 option) or for a given function only using #pragma\SpecialChar ~
4271 for (i = 0 ; i < 100 ; i ++)
4289 for (i = 0; i < 100; i++)
4299 As mentioned previously some loop invariants are not as apparent, all static
4300 address computations are also moved out of the loop.
4304 Strength Reduction, this optimization substitutes an expression by a cheaper
4311 for (i=0;i < 100; i++)
4331 for (i=0;i< 100;i++) {
4335 ar[itemp1] = itemp2;
4351 The more expensive multiplication is changed to a less expensive addition.
4352 \layout Subsubsection
4357 This optimization is done to reduce the overhead of checking loop boundaries
4358 for every iteration.
4359 Some simple loops can be reversed and implemented using a
4360 \begin_inset Quotes eld
4363 decrement and jump if not zero
4364 \begin_inset Quotes erd
4368 SDCC checks for the following criterion to determine if a loop is reversible
4369 (note: more sophisticated compilers use data-dependency analysis to make
4370 this determination, SDCC uses a more simple minded analysis).
4373 The 'for' loop is of the form
4379 for (<symbol> = <expression> ; <sym> [< | <=] <expression> ; [<sym>++ |
4389 The <for body> does not contain
4390 \begin_inset Quotes eld
4394 \begin_inset Quotes erd
4398 \begin_inset Quotes erd
4404 All goto's are contained within the loop.
4407 No function calls within the loop.
4410 The loop control variable <sym> is not assigned any value within the loop
4413 The loop control variable does NOT participate in any arithmetic operation
4417 There are NO switch statements in the loop.
4418 \layout Subsubsection
4420 Algebraic Simplifications
4423 SDCC does numerous algebraic simplifications, the following is a small sub-set
4424 of these optimizations.
4430 i = j + 0 ; /* changed to */ i = j;
4432 i /= 2; /* changed to */ i >>= 1;
4434 i = j - j ; /* changed to */ i = 0;
4436 i = j / 1 ; /* changed to */ i = j;
4442 Note the subexpressions given above are generally introduced by macro expansions
4443 or as a result of copy/constant propagation.
4444 \layout Subsubsection
4449 SDCC changes switch statements to jump tables when the following conditions
4454 The case labels are in numerical sequence, the labels need not be in order,
4455 and the starting number need not be one or zero.
4461 switch(i) {\SpecialChar ~
4568 Both the above switch statements will be implemented using a jump-table.
4571 The number of case labels is at least three, since it takes two conditional
4572 statements to handle the boundary conditions.
4575 The number of case labels is less than 84, since each label takes 3 bytes
4576 and a jump-table can be utmost 256 bytes long.
4580 Switch statements which have gaps in the numeric sequence or those that
4581 have more that 84 case labels can be split into more than one switch statement
4582 for efficient code generation, e.g.:
4620 If the above switch statement is broken down into two switch statements
4654 case 9: \SpecialChar ~
4664 case 12:\SpecialChar ~
4674 then both the switch statements will be implemented using jump-tables whereas
4675 the unmodified switch statement will not be.
4676 \layout Subsubsection
4678 Bit-shifting Operations.
4681 Bit shifting is one of the most frequently used operation in embedded programmin
4683 SDCC tries to implement bit-shift operations in the most efficient way
4703 generates the following code:
4721 In general SDCC will never setup a loop if the shift count is known.
4761 Note that SDCC stores numbers in little-endian format (i.e.
4762 lowest order first).
4763 \layout Subsubsection
4768 A special case of the bit-shift operation is bit rotation, SDCC recognizes
4769 the following expression to be a left bit-rotation:
4780 i = ((i << 1) | (i >> 7));
4788 will generate the following code:
4804 SDCC uses pattern matching on the parse tree to determine this operation.Variatio
4805 ns of this case will also be recognized as bit-rotation, i.e.:
4811 i = ((i >> 7) | (i << 1)); /* left-bit rotation */
4812 \layout Subsubsection
4817 It is frequently required to obtain the highest order bit of an integral
4818 type (long, int, short or char types).
4819 SDCC recognizes the following expression to yield the highest order bit
4820 and generates optimized code for it, e.g.:
4841 hob = (gint >> 15) & 1;
4854 will generate the following code:
4893 000A E5*01\SpecialChar ~
4921 000C 33\SpecialChar ~
4952 000D E4\SpecialChar ~
4983 000E 13\SpecialChar ~
5014 000F F5*02\SpecialChar ~
5044 Variations of this case however will
5049 It is a standard C expression, so I heartily recommend this be the only
5050 way to get the highest order bit, (it is portable).
5051 Of course it will be recognized even if it is embedded in other expressions,
5058 xyz = gint + ((gint >> 15) & 1);
5064 will still be recognized.
5065 \layout Subsubsection
5070 The compiler uses a rule based, pattern matching and re-writing mechanism
5071 for peep-hole optimization.
5076 a peep-hole optimizer by Christopher W.
5077 Fraser (cwfraser@microsoft.com).
5078 A default set of rules are compiled into the compiler, additional rules
5079 may be added with the
5081 ---peep-file <filename>
5084 The rule language is best illustrated with examples.
5112 The above rule will change the following assembly sequence:
5142 Note: All occurrences of a
5146 (pattern variable) must denote the same string.
5147 With the above rule, the assembly sequence:
5165 will remain unmodified.
5169 Other special case optimizations may be added by the user (via
5175 some variants of the 8051 MCU allow only
5184 The following two rules will change all
5206 replace { lcall %1 } by { acall %1 }
5208 replace { ljmp %1 } by { ajmp %1 }
5216 inline-assembler code
5218 is also passed through the peep hole optimizer, thus the peephole optimizer
5219 can also be used as an assembly level macro expander.
5220 The rules themselves are MCU dependent whereas the rule language infra-structur
5221 e is MCU independent.
5222 Peephole optimization rules for other MCU can be easily programmed using
5227 The syntax for a rule is as follows:
5233 rule := replace [ restart ] '{' <assembly sequence> '
5271 <assembly sequence> '
5289 '}' [if <functionName> ] '
5297 <assembly sequence> := assembly instruction (each instruction including
5298 labels must be on a separate line).
5302 The optimizer will apply to the rules one by one from the top in the sequence
5303 of their appearance, it will terminate when all rules are exhausted.
5304 If the 'restart' option is specified, then the optimizer will start matching
5305 the rules again from the top, this option for a rule is expensive (performance)
5306 , it is intended to be used in situations where a transformation will trigger
5307 the same rule again.
5308 An example of this (not a good one, it has side effects) is the following
5335 Note that the replace pattern cannot be a blank, but can be a comment line.
5336 Without the 'restart' option only the inner most 'pop' 'push' pair would
5337 be eliminated, i.e.:
5389 the restart option the rule will be applied again to the resulting code
5390 and then all the pop-push pairs will be eliminated to yield:
5408 A conditional function can be attached to a rule.
5409 Attaching rules are somewhat more involved, let me illustrate this with
5440 The optimizer does a look-up of a function name table defined in function
5445 in the source file SDCCpeeph.c, with the name
5450 If it finds a corresponding entry the function is called.
5451 Note there can be no parameters specified for these functions, in this
5456 is crucial, since the function
5460 expects to find the label in that particular variable (the hash table containin
5461 g the variable bindings is passed as a parameter).
5462 If you want to code more such functions, take a close look at the function
5463 labelInRange and the calling mechanism in source file SDCCpeeph.c.
5464 I know this whole thing is a little kludgey, but maybe some day we will
5465 have some better means.
5466 If you are looking at this file, you will also see the default rules that
5467 are compiled into the compiler, you can add your own rules in the default
5468 set there if you get tired of specifying the ---peep-file option.
5474 SDCC supports the following #pragma directives.
5475 This directives are applicable only at a function level.
5478 SAVE - this will save all the current options.
5481 RESTORE - will restore the saved options from the last save.
5482 Note that SAVES & RESTOREs cannot be nested.
5483 SDCC uses the same buffer to save the options each time a SAVE is called.
5486 NOGCSE - will stop global subexpression elimination.
5489 NOINDUCTION - will stop loop induction optimizations.
5492 NOJTBOUND - will not generate code for boundary value checking, when switch
5493 statements are turned into jump-tables.
5496 NOOVERLAY - the compiler will not overlay the parameters and local variables
5500 NOLOOPREVERSE - Will not do loop reversal optimization
5503 EXCLUDE NONE | {acc[,b[,dpl[,dph]]] - The exclude pragma disables generation
5504 of pair of push/pop instruction in ISR function (using interrupt keyword).
5505 The directive should be placed immediately before the ISR function definition
5506 and it affects ALL ISR functions following it.
5507 To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
5508 EXCLUDE\SpecialChar ~
5512 NOIV - Do not generate interrupt vector table entries for all ISR functions
5513 defined after the pragma.
5514 This is useful in cases where the interrupt vector table must be defined
5515 manually, or when there is a secondary, manually defined interrupt vector
5517 for the autovector feature of the Cypress EZ-USB FX2).
5520 CALLEE-SAVES function1[,function2[,function3...]] - The compiler by default
5521 uses a caller saves convention for register saving across function calls,
5522 however this can cause unneccessary register pushing & popping when calling
5523 small functions from larger functions.
5524 This option can be used to switch the register saving convention for the
5525 function names specified.
5526 The compiler will not save registers when calling these functions, extra
5527 code will be generated at the entry & exit for these functions to save
5528 & restore the registers used by these functions, this can SUBSTANTIALLY
5529 reduce code & improve run time performance of the generated code.
5530 In future the compiler (with interprocedural analysis) will be able to
5531 determine the appropriate scheme to use for each function call.
5532 If ---callee-saves command line option is used, the function names specified
5533 in #pragma\SpecialChar ~
5534 CALLEE-SAVES is appended to the list of functions specified inthe
5538 The pragma's are intended to be used to turn-off certain optimizations which
5539 might cause the compiler to generate extra stack / data space to store
5540 compiler generated temporary variables.
5541 This usually happens in large functions.
5542 Pragma directives should be used as shown in the following example, they
5543 are used to control options & optimizations for a given function; pragmas
5544 should be placed before and/or after a function, placing pragma's inside
5545 a function body could have unpredictable results.
5551 #pragma SAVE /* save the current settings */
5553 #pragma NOGCSE /* turnoff global subexpression elimination */
5555 #pragma NOINDUCTION /* turn off induction optimizations */
5577 #pragma RESTORE /* turn the optimizations back on */
5583 The compiler will generate a warning message when extra space is allocated.
5584 It is strongly recommended that the SAVE and RESTORE pragma's be used when
5585 changing options for a function.
5590 <pending: this is messy and incomplete>
5595 Compiler support routines (_gptrget, _mulint etc)
5598 Stdclib functions (puts, printf, strcat etc)
5601 Math functions (sin, pow, sqrt etc)
5604 Interfacing with Assembly Routines
5605 \layout Subsubsection
5607 Global Registers used for Parameter Passing
5610 The compiler always uses the global registers
5618 to pass the first parameter to a routine.
5619 The second parameter onwards is either allocated on the stack (for reentrant
5620 routines or if ---stack-auto is used) or in the internal / external ram
5621 (depending on the memory model).
5623 \layout Subsubsection
5625 Assembler Routine(non-reentrant)
5628 In the following example the function cfunc calls an assembler routine asm_func,
5629 which takes two parameters.
5635 extern int asm_func(unsigned char, unsigned char);
5639 int c_func (unsigned char i, unsigned char j)
5647 return asm_func(i,j);
5661 return c_func(10,9);
5669 The corresponding assembler function is:
5675 .globl _asm_func_PARM_2
5739 add a,_asm_func_PARM_2
5775 Note here that the return values are placed in 'dpl' - One byte return value,
5776 'dpl' LSB & 'dph' MSB for two byte values.
5777 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
5778 b' & 'acc' for four byte values.
5781 The parameter naming convention is _<function_name>_PARM_<n>, where n is
5782 the parameter number starting from 1, and counting from the left.
5783 The first parameter is passed in
5784 \begin_inset Quotes eld
5788 \begin_inset Quotes erd
5791 for One bye parameter,
5792 \begin_inset Quotes eld
5796 \begin_inset Quotes erd
5800 \begin_inset Quotes eld
5804 \begin_inset Quotes erd
5808 \begin_inset Quotes eld
5812 \begin_inset Quotes erd
5815 for four bytes, the varible name for the second parameter will be _<function_na
5820 Assemble the assembler routine with the following command:
5827 asx8051 -losg asmfunc.asm
5834 Then compile and link the assembler routine to the C source file with the
5842 sdcc cfunc.c asmfunc.rel
5843 \layout Subsubsection
5845 Assembler Routine(reentrant)
5848 In this case the second parameter onwards will be passed on the stack, the
5849 parameters are pushed from right to left i.e.
5850 after the call the left most parameter will be on the top of the stack.
5857 extern int asm_func(unsigned char, unsigned char);
5861 int c_func (unsigned char i, unsigned char j) reentrant
5869 return asm_func(i,j);
5883 return c_func(10,9);
5891 The corresponding assembler routine is:
6001 The compiling and linking procedure remains the same, however note the extra
6002 entry & exit linkage required for the assembler code, _bp is the stack
6003 frame pointer and is used to compute the offset into the stack for parameters
6004 and local variables.
6010 The external stack is located at the start of the external ram segment,
6011 and is 256 bytes in size.
6012 When ---xstack option is used to compile the program, the parameters and
6013 local variables of all reentrant functions are allocated in this area.
6014 This option is provided for programs with large stack space requirements.
6015 When used with the ---stack-auto option, all parameters and local variables
6016 are allocated on the external stack (note support libraries will need to
6017 be recompiled with the same options).
6020 The compiler outputs the higher order address byte of the external ram segment
6021 into PORT P2, therefore when using the External Stack option, this port
6022 MAY NOT be used by the application program.
6028 Deviations from the compliancy.
6031 functions are not always reentrant.
6034 structures cannot be assigned values directly, cannot be passed as function
6035 parameters or assigned to each other and cannot be a return value from
6062 s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
6073 struct s foo1 (struct s parms) /* is invalid in SDCC although allowed in
6095 return rets;/* is invalid in SDCC although allowed in ANSI */
6100 'long long' (64 bit integers) not supported.
6103 'double' precision floating point not supported.
6106 No support for setjmp and longjmp (for now).
6109 Old K&R style function declarations are NOT allowed.
6115 foo(i,j) /* this old style of function declarations */
6117 int i,j; /* are valid in ANSI but not valid in SDCC */
6131 functions declared as pointers must be dereferenced during the call.
6142 /* has to be called like this */
6144 (*foo)(); /* ansi standard allows calls to be made like 'foo()' */
6147 Cyclomatic Complexity
6150 Cyclomatic complexity of a function is defined as the number of independent
6151 paths the program can take during execution of the function.
6152 This is an important number since it defines the number test cases you
6153 have to generate to validate the function.
6154 The accepted industry standard for complexity number is 10, if the cyclomatic
6155 complexity reported by SDCC exceeds 10 you should think about simplification
6156 of the function logic.
6157 Note that the complexity level is not related to the number of lines of
6159 Large functions can have low complexity, and small functions can have large
6165 SDCC uses the following formula to compute the complexity:
6170 complexity = (number of edges in control flow graph) - (number of nodes
6171 in control flow graph) + 2;
6175 Having said that the industry standard is 10, you should be aware that in
6176 some cases it be may unavoidable to have a complexity level of less than
6178 For example if you have switch statement with more than 10 case labels,
6179 each case label adds one to the complexity level.
6180 The complexity level is by no means an absolute measure of the algorithmic
6181 complexity of the function, it does however provide a good starting point
6182 for which functions you might look at for further optimization.
6188 Here are a few guidelines that will help the compiler generate more efficient
6189 code, some of the tips are specific to this compiler others are generally
6190 good programming practice.
6193 Use the smallest data type to represent your data-value.
6194 If it is known in advance that the value is going to be less than 256 then
6195 use an 'unsigned char' instead of a 'short' or 'int'.
6198 Use unsigned when it is known in advance that the value is not going to
6200 This helps especially if you are doing division or multiplication.
6203 NEVER jump into a LOOP.
6206 Declare the variables to be local whenever possible, especially loop control
6207 variables (induction).
6210 Since the compiler does not always do implicit integral promotion, the programme
6211 r should do an explicit cast when integral promotion is required.
6214 Reducing the size of division, multiplication & modulus operations can reduce
6215 code size substantially.
6216 Take the following code for example.
6222 foobar(unsigned int p1, unsigned char ch)
6226 unsigned char ch1 = p1 % ch ;
6237 For the modulus operation the variable ch will be promoted to unsigned int
6238 first then the modulus operation will be performed (this will lead to a
6239 call to support routine _moduint()), and the result will be casted to a
6241 If the code is changed to
6247 foobar(unsigned int p1, unsigned char ch)
6251 unsigned char ch1 = (unsigned char)p1 % ch ;
6262 It would substantially reduce the code generated (future versions of the
6263 compiler will be smart enough to detect such optimization oppurtunities).
6266 Notes on MCS51 memory layout
6269 The 8051 family of micro controller have a minimum of 128 bytes of internal
6270 memory which is structured as follows
6274 - Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R7 to R7
6277 - Bytes 20-2F - 16 bytes to hold 128 bit variables and
6279 - Bytes 30-7F - 60 bytes for general purpose use.
6283 Normally the SDCC compiler will only utilise the first bank of registers,
6284 but it is possible to specify that other banks of registers should be used
6285 in interrupt routines.
6286 By default, the compiler will place the stack after the last bank of used
6288 if the first 2 banks of registers are used, it will position the base of
6289 the internal stack at address 16 (0X10).
6290 This implies that as the stack grows, it will use up the remaining register
6291 banks, and the 16 bytes used by the 128 bit variables, and 60 bytes for
6292 general purpose use.
6295 By default, the compiler uses the 60 general purpose bytes to hold "near
6297 The compiler/optimiser may also declare some Local Variables in this area
6302 If any of the 128 bit variables are used, or near data is being used then
6303 care needs to be taken to ensure that the stack does not grow so much that
6304 it starts to over write either your bit variables or "near data".
6305 There is no runtime checking to prevent this from happening.
6308 The amount of stack being used is affected by the use of the "internal stack"
6309 to save registers before a subroutine call is made (---stack-auto will
6310 declare parameters and local variables on the stack) and the number of
6314 If you detect that the stack is over writing you data, then the following
6316 ---xstack will cause an external stack to be used for saving registers
6317 and (if ---stack-auto is being used) storing parameters and local variables.
6318 However this will produce more code which will be slower to execute.
6322 ---stack-loc will allow you specify the start of the stack, i.e.
6323 you could start it after any data in the general purpose area.
6324 However this may waste the memory not used by the register banks and if
6325 the size of the "near data" increases, it may creep into the bottom of
6329 ---stack-after-data, similar to the ---stack-loc, but it automatically places
6330 the stack after the end of the "near data".
6331 Again this could waste any spare register space.
6334 ---data-loc allows you to specify the start address of the near data.
6335 This could be used to move the "near data" further away from the stack
6336 giving it more room to grow.
6337 This will only work if no bit variables are being used and the stack can
6338 grow to use the bit variable space.
6346 If you find that the stack is over writing your bit variables or "near data"
6347 then the approach which best utilised the internal memory is to position
6348 the "near data" after the last bank of used registers or, if you use bit
6349 variables, after the last bit variable by using the ---data-loc, e.g.
6350 if two register banks are being used and no bit variables, ---data-loc
6351 16, and use the ---stack-after-data option.
6354 If bit variables are being used, another method would be to try and squeeze
6355 the data area in the unused register banks if it will fit, and start the
6356 stack after the last bit variable.
6359 Retargetting for other MCUs.
6362 The issues for retargetting the compiler are far too numerous to be covered
6364 What follows is a brief description of each of the seven phases of the
6365 compiler and its MCU dependency.
6368 Parsing the source and building the annotated parse tree.
6369 This phase is largely MCU independent (except for the language extensions).
6370 Syntax & semantic checks are also done in this phase, along with some initial
6371 optimizations like back patching labels and the pattern matching optimizations
6372 like bit-rotation etc.
6375 The second phase involves generating an intermediate code which can be easy
6376 manipulated during the later phases.
6377 This phase is entirely MCU independent.
6378 The intermediate code generation assumes the target machine has unlimited
6379 number of registers, and designates them with the name iTemp.
6380 The compiler can be made to dump a human readable form of the code generated
6381 by using the ---dumpraw option.
6384 This phase does the bulk of the standard optimizations and is also MCU independe
6386 This phase can be broken down into several sub-phases:
6390 Break down intermediate code (iCode) into basic blocks.
6392 Do control flow & data flow analysis on the basic blocks.
6394 Do local common subexpression elimination, then global subexpression elimination
6396 Dead code elimination
6400 If loop optimizations caused any changes then do 'global subexpression eliminati
6401 on' and 'dead code elimination' again.
6404 This phase determines the live-ranges; by live range I mean those iTemp
6405 variables defined by the compiler that still survive after all the optimization
6407 Live range analysis is essential for register allocation, since these computati
6408 on determines which of these iTemps will be assigned to registers, and for
6412 Phase five is register allocation.
6413 There are two parts to this process.
6417 The first part I call 'register packing' (for lack of a better term).
6418 In this case several MCU specific expression folding is done to reduce
6423 The second part is more MCU independent and deals with allocating registers
6424 to the remaining live ranges.
6425 A lot of MCU specific code does creep into this phase because of the limited
6426 number of index registers available in the 8051.
6429 The Code generation phase is (unhappily), entirely MCU dependent and very
6430 little (if any at all) of this code can be reused for other MCU.
6431 However the scheme for allocating a homogenized assembler operand for each
6432 iCode operand may be reused.
6435 As mentioned in the optimization section the peep-hole optimizer is rule
6436 based system, which can reprogrammed for other MCUs.
6439 SDCDB - Source Level Debugger
6442 SDCC is distributed with a source level debugger.
6443 The debugger uses a command line interface, the command repertoire of the
6444 debugger has been kept as close to gdb (the GNU debugger) as possible.
6445 The configuration and build process is part of the standard compiler installati
6446 on, which also builds and installs the debugger in the target directory
6447 specified during configuration.
6448 The debugger allows you debug BOTH at the C source and at the ASM source
6452 Compiling for Debugging
6457 debug option must be specified for all files for which debug information
6459 The complier generates a .cdb file for each of these files.
6460 The linker updates the .cdb file with the address information.
6461 This .cdb is used by the debugger.
6464 How the Debugger Works
6467 When the ---debug option is specified the compiler generates extra symbol
6468 information some of which are put into the the assembler source and some
6469 are put into the .cdb file, the linker updates the .cdb file with the address
6470 information for the symbols.
6471 The debugger reads the symbolic information generated by the compiler &
6472 the address information generated by the linker.
6473 It uses the SIMULATOR (Daniel's S51) to execute the program, the program
6474 execution is controlled by the debugger.
6475 When a command is issued for the debugger, it translates it into appropriate
6476 commands for the simulator.
6479 Starting the Debugger
6482 The debugger can be started using the following command line.
6483 (Assume the file you are debugging has the file name foo).
6497 The debugger will look for the following files.
6500 foo.c - the source file.
6503 foo.cdb - the debugger symbol information file.
6506 foo.ihx - the intel hex format object file.
6509 Command Line Options.
6512 ---directory=<source file directory> this option can used to specify the
6513 directory search list.
6514 The debugger will look into the directory list specified for source, cdb
6516 The items in the directory list must be separated by ':', e.g.
6517 if the source files can be in the directories /home/src1 and /home/src2,
6518 the ---directory option should be ---directory=/home/src1:/home/src2.
6519 Note there can be no spaces in the option.
6523 -cd <directory> - change to the <directory>.
6526 -fullname - used by GUI front ends.
6529 -cpu <cpu-type> - this argument is passed to the simulator please see the
6530 simulator docs for details.
6533 -X <Clock frequency > this options is passed to the simulator please see
6534 the simulator docs for details.
6537 -s <serial port file> passed to simulator see the simulator docs for details.
6540 -S <serial in,out> passed to simulator see the simulator docs for details.
6546 As mention earlier the command interface for the debugger has been deliberately
6547 kept as close the GNU debugger gdb, as possible.
6548 This will help the integration with existing graphical user interfaces
6549 (like ddd, xxgdb or xemacs) existing for the GNU debugger.
6550 \layout Subsubsection
6552 break [line | file:line | function | file:function]
6555 Set breakpoint at specified line or function:
6564 sdcdb>break foo.c:100
6568 sdcdb>break foo.c:funcfoo
6569 \layout Subsubsection
6571 clear [line | file:line | function | file:function ]
6574 Clear breakpoint at specified line or function:
6583 sdcdb>clear foo.c:100
6587 sdcdb>clear foo.c:funcfoo
6588 \layout Subsubsection
6593 Continue program being debugged, after breakpoint.
6594 \layout Subsubsection
6599 Execute till the end of the current function.
6600 \layout Subsubsection
6605 Delete breakpoint number 'n'.
6606 If used without any option clear ALL user defined break points.
6607 \layout Subsubsection
6609 info [break | stack | frame | registers ]
6612 info break - list all breakpoints
6615 info stack - show the function call stack.
6618 info frame - show information about the current execution frame.
6621 info registers - show content of all registers.
6622 \layout Subsubsection
6627 Step program until it reaches a different source line.
6628 \layout Subsubsection
6633 Step program, proceeding through subroutine calls.
6634 \layout Subsubsection
6639 Start debugged program.
6640 \layout Subsubsection
6645 Print type information of the variable.
6646 \layout Subsubsection
6651 print value of variable.
6652 \layout Subsubsection
6657 load the given file name.
6658 Note this is an alternate method of loading file for debugging.
6659 \layout Subsubsection
6664 print information about current frame.
6665 \layout Subsubsection
6670 Toggle between C source & assembly source.
6671 \layout Subsubsection
6676 Send the string following '!' to the simulator, the simulator response is
6678 Note the debugger does not interpret the command being sent to the simulator,
6679 so if a command like 'go' is sent the debugger can loose its execution
6680 context and may display incorrect values.
6681 \layout Subsubsection
6688 My name is Bobby Brown"
6691 Interfacing with XEmacs.
6694 Two files (in emacs lisp) are provided for the interfacing with XEmacs,
6695 sdcdb.el and sdcdbsrc.el.
6696 These two files can be found in the $(prefix)/bin directory after the installat
6698 These files need to be loaded into XEmacs for the interface to work.
6699 This can be done at XEmacs startup time by inserting the following into
6700 your '.xemacs' file (which can be found in your HOME directory):
6706 (load-file sdcdbsrc.el)
6712 .xemacs is a lisp file so the () around the command is REQUIRED.
6713 The files can also be loaded dynamically while XEmacs is running, set the
6714 environment variable 'EMACSLOADPATH' to the installation bin directory
6715 (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
6716 To start the interface enter the following command:
6730 You will prompted to enter the file name to be debugged.
6735 The command line options that are passed to the simulator directly are bound
6736 to default values in the file sdcdbsrc.el.
6737 The variables are listed below, these values maybe changed as required.
6740 sdcdbsrc-cpu-type '51
6743 sdcdbsrc-frequency '11059200
6749 The following is a list of key mapping for the debugger interface.
6757 ;; Current Listing ::
6774 binding\SpecialChar ~
6813 ------\SpecialChar ~
6853 sdcdb-next-from-src\SpecialChar ~
6879 sdcdb-back-from-src\SpecialChar ~
6905 sdcdb-cont-from-src\SpecialChar ~
6915 SDCDB continue command
6931 sdcdb-step-from-src\SpecialChar ~
6957 sdcdb-whatis-c-sexp\SpecialChar ~
6967 SDCDB ptypecommand for data at
7031 sdcdbsrc-delete\SpecialChar ~
7045 SDCDB Delete all breakpoints if no arg
7093 given or delete arg (C-u arg x)
7109 sdcdbsrc-frame\SpecialChar ~
7124 SDCDB Display current frame if no arg,
7173 given or display frame arg
7238 sdcdbsrc-goto-sdcdb\SpecialChar ~
7248 Goto the SDCDB output buffer
7264 sdcdb-print-c-sexp\SpecialChar ~
7275 SDCDB print command for data at
7339 sdcdbsrc-goto-sdcdb\SpecialChar ~
7349 Goto the SDCDB output buffer
7365 sdcdbsrc-mode\SpecialChar ~
7381 Toggles Sdcdbsrc mode (turns it off)
7385 ;; C-c C-f\SpecialChar ~
7393 sdcdb-finish-from-src\SpecialChar ~
7401 SDCDB finish command
7405 ;; C-x SPC\SpecialChar ~
7413 sdcdb-break\SpecialChar ~
7431 Set break for line with point
7433 ;; ESC t\SpecialChar ~
7443 sdcdbsrc-mode\SpecialChar ~
7459 Toggle Sdcdbsrc mode
7461 ;; ESC m\SpecialChar ~
7471 sdcdbsrc-srcmode\SpecialChar ~
7495 The Z80 and gbz80 port
7498 SDCC can target both the Zilog Z80 and the Nintendo Gameboy's Z80-like gbz80.
7499 The port is incomplete - long support is incomplete (mul, div and mod are
7500 unimplimented), and both float and bitfield support is missing.
7501 Apart from that the code generated is correct.
7504 As always, the code is the authoritave reference - see z80/ralloc.c and z80/gen.c.
7505 The stack frame is similar to that generated by the IAR Z80 compiler.
7506 IX is used as the base pointer, HL is used as a temporary register, and
7507 BC and DE are available for holding varibles.
7508 IY is currently unusued.
7509 Return values are stored in HL.
7510 One bad side effect of using IX as the base pointer is that a functions
7511 stack frame is limited to 127 bytes - this will be fixed in a later version.
7517 SDCC has grown to be a large project.
7518 The compiler alone (without the preprocessor, assembler and linker) is
7519 about 40,000 lines of code (blank stripped).
7520 The open source nature of this project is a key to its continued growth
7522 You gain the benefit and support of many active software developers and
7524 Is SDCC perfect? No, that's why we need your help.
7525 The developers take pride in fixing reported bugs.
7526 You can help by reporting the bugs and helping other SDCC users.
7527 There are lots of ways to contribute, and we encourage you to take part
7528 in making SDCC a great software package.
7534 Send an email to the mailing list at 'user-sdcc@sdcc.sourceforge.net' or 'devel-sd
7535 cc@sdcc.sourceforge.net'.
7536 Bugs will be fixed ASAP.
7537 When reporting a bug, it is very useful to include a small test program
7538 which reproduces the problem.
7539 If you can isolate the problem by looking at the generated assembly code,
7540 this can be very helpful.
7541 Compiling your program with the ---dumpall option can sometimes be useful
7542 in locating optimization problems.
7545 The anatomy of the compiler
7550 This is an excerpt from an atricle published in Circuit Cellar MagaZine
7552 It's a little outdated (the compiler is much more efficient now and user/devell
7553 oper friendly), but pretty well exposes the guts of it all.
7559 The current version of SDCC can generate code for Intel 8051 and Z80 MCU.
7560 It is fairly easy to retarget for other 8-bit MCU.
7561 Here we take a look at some of the internals of the compiler.
7568 Parsing the input source file and creating an AST (Annotated Syntax Tree).
7569 This phase also involves propagating types (annotating each node of the
7570 parse tree with type information) and semantic analysis.
7571 There are some MCU specific parsing rules.
7572 For example the storage classes, the extended storage classes are MCU specific
7573 while there may be a xdata storage class for 8051 there is no such storage
7574 class for z80 or Atmel AVR.
7575 SDCC allows MCU specific storage class extensions, i.e.
7576 xdata will be treated as a storage class specifier when parsing 8051 C
7577 code but will be treated as a C identifier when parsing z80 or ATMEL AVR
7584 Intermediate code generation.
7585 In this phase the AST is broken down into three-operand form (iCode).
7586 These three operand forms are represented as doubly linked lists.
7587 ICode is the term given to the intermediate form generated by the compiler.
7588 ICode example section shows some examples of iCode generated for some simple
7595 Bulk of the target independent optimizations is performed in this phase.
7596 The optimizations include constant propagation, common sub-expression eliminati
7597 on, loop invariant code movement, strength reduction of loop induction variables
7598 and dead-code elimination.
7604 During intermediate code generation phase, the compiler assumes the target
7605 machine has infinite number of registers and generates a lot of temporary
7607 The live range computation determines the lifetime of each of these compiler-ge
7608 nerated temporaries.
7609 A picture speaks a thousand words.
7610 ICode example sections show the live range annotations for each of the
7612 It is important to note here, each iCode is assigned a number in the order
7613 of its execution in the function.
7614 The live ranges are computed in terms of these numbers.
7615 The from number is the number of the iCode which first defines the operand
7616 and the to number signifies the iCode which uses this operand last.
7622 The register allocation determines the type and number of registers needed
7624 In most MCUs only a few registers can be used for indirect addressing.
7625 In case of 8051 for example the registers R0 & R1 can be used to indirectly
7626 address the internal ram and DPTR to indirectly address the external ram.
7627 The compiler will try to allocate the appropriate register to pointer variables
7629 ICode example section shows the operands annotated with the registers assigned
7631 The compiler will try to keep operands in registers as much as possible;
7632 there are several schemes the compiler uses to do achieve this.
7633 When the compiler runs out of registers the compiler will check to see
7634 if there are any live operands which is not used or defined in the current
7635 basic block being processed, if there are any found then it will push that
7636 operand and use the registers in this block, the operand will then be popped
7637 at the end of the basic block.
7641 There are other MCU specific considerations in this phase.
7642 Some MCUs have an accumulator; very short-lived operands could be assigned
7643 to the accumulator instead of general-purpose register.
7649 Figure II gives a table of iCode operations supported by the compiler.
7650 The code generation involves translating these operations into corresponding
7651 assembly code for the processor.
7652 This sounds overly simple but that is the essence of code generation.
7653 Some of the iCode operations are generated on a MCU specific manner for
7654 example, the z80 port does not use registers to pass parameters so the
7655 SEND and RECV iCode operations will not be generated, and it also does
7656 not support JUMPTABLES.
7663 <Where is Figure II ?>
7669 This section shows some details of iCode.
7670 The example C code does not do anything useful; it is used as an example
7671 to illustrate the intermediate code generated by the compiler.
7684 /* This function does nothing useful.
7691 for the purpose of explaining iCode */
7694 short function (data int *x)
7702 short i=10; /* dead initialization eliminated */
7707 short sum=10; /* dead initialization eliminated */
7720 while (*x) *x++ = *p++;
7734 /* compiler detects i,j to be induction variables */
7738 for (i = 0, j = 10 ; i < 10 ; i++, j---) {
7750 mul += i * 3; /* this multiplication remains */
7756 gint += j * 3;/* this multiplication changed to addition */
7773 In addition to the operands each iCode contains information about the filename
7774 and line it corresponds to in the source file.
7775 The first field in the listing should be interpreted as follows:
7780 Filename(linenumber: iCode Execution sequence number : ICode hash table
7781 key : loop depth of the iCode).
7786 Then follows the human readable form of the ICode operation.
7787 Each operand of this triplet form can be of three basic types a) compiler
7788 generated temporary b) user defined variable c) a constant value.
7789 Note that local variables and parameters are replaced by compiler generated
7791 Live ranges are computed only for temporaries (i.e.
7792 live ranges are not computed for global variables).
7793 Registers are allocated for temporaries only.
7794 Operands are formatted in the following manner:
7799 Operand Name [lr live-from : live-to ] { type information } [ registers
7805 As mentioned earlier the live ranges are computed in terms of the execution
7806 sequence number of the iCodes, for example
7808 the iTemp0 is live from (i.e.
7809 first defined in iCode with execution sequence number 3, and is last used
7810 in the iCode with sequence number 5).
7811 For induction variables such as iTemp21 the live range computation extends
7812 the lifetime from the start to the end of the loop.
7814 The register allocator used the live range information to allocate registers,
7815 the same registers may be used for different temporaries if their live
7816 ranges do not overlap, for example r0 is allocated to both iTemp6 and to
7817 iTemp17 since their live ranges do not overlap.
7818 In addition the allocator also takes into consideration the type and usage
7819 of a temporary, for example itemp6 is a pointer to near space and is used
7820 as to fetch data from (i.e.
7821 used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer registers (r0).
7822 Some short lived temporaries are allocated to special registers which have
7823 meaning to the code generator e.g.
7824 iTemp13 is allocated to a pseudo register CC which tells the back end that
7825 the temporary is used only for a conditional jump the code generation makes
7826 use of this information to optimize a compare and jump ICode.
7828 There are several loop optimizations performed by the compiler.
7829 It can detect induction variables iTemp21(i) and iTemp23(j).
7830 Also note the compiler does selective strength reduction, i.e.
7831 the multiplication of an induction variable in line 18 (gint = j * 3) is
7832 changed to addition, a new temporary iTemp17 is allocated and assigned
7833 a initial value, a constant 3 is then added for each iteration of the loop.
7834 The compiler does not change the multiplication in line 17 however since
7835 the processor does support an 8 * 8 bit multiplication.
7837 Note the dead code elimination optimization eliminated the dead assignments
7838 in line 7 & 8 to I and sum respectively.
7845 Sample.c (5:1:0:0) _entry($9) :
7850 Sample.c(5:2:1:0) proc _function [lr0:0]{function short}
7855 Sample.c(11:3:2:0) iTemp0 [lr3:5]{_near * int}[r2] = recv
7860 Sample.c(11:4:53:0) preHeaderLbl0($11) :
7865 Sample.c(11:5:55:0) iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near
7871 Sample.c(11:6:5:1) _whilecontinue_0($1) :
7876 Sample.c(11:7:7:1) iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near *
7882 Sample.c(11:8:8:1) if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
7887 Sample.c(11:9:14:1) iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far
7893 Sample.c(11:10:15:1) _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2
7899 Sample.c(11:13:18:1) iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far
7905 Sample.c(11:14:19:1) *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int
7911 Sample.c(11:15:12:1) iTemp6 [lr5:16]{_near * int}[r0] = iTemp6 [lr5:16]{_near
7912 * int}[r0] + 0x2 {short}
7917 Sample.c(11:16:20:1) goto _whilecontinue_0($1)
7922 Sample.c(11:17:21:0)_whilebreak_0($3) :
7927 Sample.c(12:18:22:0) iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
7932 Sample.c(13:19:23:0) iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
7937 Sample.c(15:20:54:0)preHeaderLbl1($13) :
7942 Sample.c(15:21:56:0) iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
7947 Sample.c(15:22:57:0) iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
7952 Sample.c(15:23:58:0) iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
7957 Sample.c(15:24:26:1)_forcond_0($4) :
7962 Sample.c(15:25:27:1) iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4]
7968 Sample.c(15:26:28:1) if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
7973 Sample.c(16:27:31:1) iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2]
7974 + ITemp21 [lr21:38]{short}[r4]
7979 Sample.c(17:29:33:1) iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4]
7985 Sample.c(17:30:34:1) iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3]
7986 + iTemp15 [lr29:30]{short}[r1]
7991 Sample.c(18:32:36:1:1) iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7
7997 Sample.c(18:33:37:1) _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{
8003 Sample.c(15:36:42:1) iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4]
8009 Sample.c(15:37:45:1) iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5
8015 Sample.c(19:38:47:1) goto _forcond_0($4)
8020 Sample.c(19:39:48:0)_forbreak_0($7) :
8025 Sample.c(20:40:49:0) iTemp24 [lr40:41]{short}[DPTR] = iTemp2 [lr18:40]{short}[r2]
8026 + ITemp11 [lr19:40]{short}[r3]
8031 Sample.c(20:41:50:0) ret iTemp24 [lr40:41]{short}
8036 Sample.c(20:42:51:0)_return($8) :
8041 Sample.c(20:43:52:0) eproc _function [lr0:0]{ ia0 re0 rm0}{function short}
8047 Finally the code generated for this function:
8088 ; ----------------------------------------------
8098 ; ----------------------------------------------
8108 ; iTemp0 [lr3:5]{_near * int}[r2] = recv
8120 ; iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near * int}[r2]
8132 ;_whilecontinue_0($1) :
8142 ; iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near * int}[r0]]
8147 ; if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
8206 ; iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far * int}
8225 ; _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2 {short}
8272 ; iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far * int}[DPTR]]
8312 ; *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int}[r2 r3]
8338 ; iTemp6 [lr5:16]{_near * int}[r0] =
8343 ; iTemp6 [lr5:16]{_near * int}[r0] +
8360 ; goto _whilecontinue_0($1)
8372 ; _whilebreak_0($3) :
8382 ; iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
8394 ; iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
8406 ; iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
8418 ; iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
8437 ; iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
8466 ; iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4] < 0xa {short}
8471 ; if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
8516 ; iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2] +
8521 ; iTemp21 [lr21:38]{short}[r4]
8547 ; iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4] * 0x3 {short}
8580 ; iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3] +
8585 ; iTemp15 [lr29:30]{short}[r1]
8604 ; iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7 r0]- 0x3 {short}
8651 ; _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{int}[r7 r0]
8698 ; iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4] + 0x1 {short}
8710 ; iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5 r6]- 0x1 {short}
8724 cjne r5,#0xff,00104$
8736 ; goto _forcond_0($4)
8758 ; ret iTemp24 [lr40:41]{short}
8807 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net#Who}
8817 Thanks to all the other volunteer developers who have helped with coding,
8818 testing, web-page creation, distribution sets, etc.
8819 You know who you are :-)
8826 This document was initially written by Sandeep Dutta
8829 All product names mentioned herein may be trademarks of their respective
8835 \begin_inset LatexCommand \printindex{}
projects / fw / sdcc / blob