1 #LyX 1.3 created this file. For more info see http://www.lyx.org/
6 pdftitle={SDCC Compiler User Guide},
7 pdfauthor={SDCC development team},
8 pdfsubject={installation, user manual},
9 pdfkeywords={8032, 8051, ansi, c, compiler, CPU, DS390,
10 embedded, GPL, manual, mcs51, PIC, small, Z80},
12 linkcolor=blue] {hyperref}
16 \inputencoding default
19 \paperfontsize default
26 \use_numerical_citations 0
27 \paperorientation portrait
34 \paragraph_separation indent
36 \quotes_language swedish
44 Please note: double dashed longoptions (e.g.
45 --version) are written this way: -
59 three consecutive dashes simply result in a long resp.
63 SDCC Compiler User Guide
69 The strings enclosed in $ are automatically updated by cvs:
74 cvs: $Revision$ $Date$
78 \begin_inset LatexCommand \tableofcontents{}
95 is a Freeware, retargettable, optimizing ANSI-C compiler by
99 designed for 8 bit Microprocessors.
100 The current version targets Intel MCS51 based Microprocessors (8031, 8032,
102 \begin_inset LatexCommand \index{8031, 8032, 8051, 8052 CPU}
106 , etc), Zilog Z80 based MCUs, and the Dallas DS80C390 variant.
107 It can be retargetted for other microprocessors, support for PIC, AVR and
108 186 is under development.
109 The entire source code for the compiler is distributed under GPL.
110 SDCC uses ASXXXX & ASLINK, a Freeware, retargettable assembler & linker.
111 SDCC has extensive language extensions suitable for utilizing various microcont
112 rollers and underlying hardware effectively.
117 In addition to the MCU specific optimizations SDCC also does a host of standard
121 global sub expression elimination,
124 loop optimizations (loop invariant, strength reduction of induction variables
128 constant folding & propagation,
134 dead code elimination
144 For the back-end SDCC uses a global register allocation scheme which should
145 be well suited for other 8 bit MCUs.
150 The peep hole optimizer uses a rule based substitution mechanism which is
156 Supported data-types are:
159 char (8 bits, 1 byte),
162 short and int (16 bits, 2 bytes),
165 long (32 bit, 4 bytes)
172 The compiler also allows
174 inline assembler code
176 to be embedded anywhere in a function.
177 In addition, routines developed in assembly can also be called.
181 SDCC also provides an option (-
191 -cyclomatic) to report the relative complexity of a function.
192 These functions can then be further optimized, or hand coded in assembly
198 SDCC also comes with a companion source level debugger SDCDB, the debugger
199 currently uses ucSim a freeware simulator for 8051 and other micro-controllers.
204 The latest version can be downloaded from
205 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
215 Please note: the compiler will probably always be some steps ahead of this
220 \begin_inset LatexCommand \index{Status of documentation}
230 Obviously this has pros and cons
239 All packages used in this compiler system are
247 ; source code for all the sub-packages (pre-processor, assemblers, linkers
248 etc) is distributed with the package.
249 This documentation is maintained using a freeware word processor (LyX).
251 This program is free software; you can redistribute it and/or modify it
252 under the terms of the GNU General Public License
253 \begin_inset LatexCommand \index{GNU General Public License, GPL}
257 as published by the Free Software Foundation; either version 2, or (at
258 your option) any later version.
259 This program is distributed in the hope that it will be useful, but WITHOUT
260 ANY WARRANTY; without even the implied warranty
261 \begin_inset LatexCommand \index{warranty}
265 of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
266 See the GNU General Public License for more details.
267 You should have received a copy of the GNU General Public License along
268 with this program; if not, write to the Free Software Foundation, 59 Temple
269 Place - Suite 330, Boston, MA 02111-1307, USA.
270 In other words, you are welcome to use, share and improve this program.
271 You are forbidden to forbid anyone else to use, share and improve what
273 Help stamp out software-hoarding!
276 Typographic conventions
277 \begin_inset LatexCommand \index{Typographic conventions}
284 Throughout this manual, we will use the following convention.
285 Commands you have to type in are printed in
293 Code samples are printed in
298 Interesting items and new terms are printed in
303 Compatibility with previous versions
306 This version has numerous bug fixes compared with the previous version.
307 But we also introduced some incompatibilities with older versions.
308 Not just for the fun of it, but to make the compiler more stable, efficient
310 \begin_inset LatexCommand \index{ANSI-compliance}
320 short is now equivalent to int (16 bits), it used to be equivalent to char
321 (8 bits) which is not ANSI compliant
324 the default directory for gcc-builds where include, library and documentation
325 files are stored is now in /usr/local/share
328 char type parameters to vararg functions are casted to int unless explicitly
345 will push a as an int and as a char resp.
358 -regextend has been removed
371 -noregparms has been removed
384 -stack-after-data has been removed
389 <pending: more incompatibilities?>
395 What do you need before you start installation of SDCC? A computer, and
397 The preferred method of installation is to compile SDCC from source using
399 For Windows some pre-compiled binary distributions are available for your
401 You should have some experience with command line tools and compiler use.
407 The SDCC home page at
408 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
412 is a great place to find distribution sets.
413 You can also find links to the user mailing lists that offer help or discuss
414 SDCC with other SDCC users.
415 Web links to other SDCC related sites can also be found here.
416 This document can be found in the DOC directory of the source package as
418 Some of the other tools (simulator and assembler) included with SDCC contain
419 their own documentation and can be found in the source distribution.
420 If you want the latest unreleased software, the complete source package
421 is available directly by anonymous CVS on cvs.sdcc.sourceforge.net.
424 ANSI C reference / related tools / recommended reading / compiler building:
428 Wishes for the future
431 There are (and always will be) some things that could be done.
432 Here are some I can think of:
439 char KernelFunction3(char p) at 0x340;
447 \begin_inset LatexCommand \index{code banking (not supported)}
455 If you can think of some more, please see the chapter 9 about filing feature
457 \begin_inset LatexCommand \index{Requesting features}
462 \begin_inset LatexCommand \index{Feature request}
472 \begin_inset LatexCommand \index{Installation}
480 \begin_inset LatexCommand \index{Options SDCC configuration}
487 The install paths, search paths and other options are defined when running
489 The defaults can be overridden by:
491 \labelwidthstring 00.00.0000
503 -prefix see table below
505 \labelwidthstring 00.00.0000
517 -exec_prefix see table below
519 \labelwidthstring 00.00.0000
531 -bindir see table below
533 \labelwidthstring 00.00.0000
545 -datadir see table below
547 \labelwidthstring 00.00.0000
549 docdir environment variable, see table below
551 \labelwidthstring 00.00.0000
553 include_dir_suffix environment variable, see table below
555 \labelwidthstring 00.00.0000
557 lib_dir_suffix environment variable, see table below
559 \labelwidthstring 00.00.0000
561 sdccconf_h_dir_separator environment variable, either / or
566 This character will only be used in sdccconf.h; don't forget it's a C-header,
567 therefore a double-backslash is needed there.
569 \labelwidthstring 00.00.0000
581 -disable-mcs51-port Excludes the Intel mcs51 port
583 \labelwidthstring 00.00.0000
595 -disable-gbz80-port Excludes the Gameboy gbz80 port
597 \labelwidthstring 00.00.0000
609 -z80-port Excludes the z80 port
611 \labelwidthstring 00.00.0000
623 -disable-avr-port Excludes the AVR port
625 \labelwidthstring 00.00.0000
637 -disable-ds390-port Excludes the DS390 port
639 \labelwidthstring 00.00.0000
651 -disable-pic-port Excludes the PIC port
653 \labelwidthstring 00.00.0000
665 -disable-xa51-port Excludes the XA51 port
667 \labelwidthstring 00.00.0000
679 -disable-ucsim Disables configuring and building of ucsim
681 \labelwidthstring 00.00.0000
693 -disable-device-lib-build Disables automatically building device libraries
695 \labelwidthstring 00.00.0000
707 -disable-packihx Disables building packihx
709 \labelwidthstring 00.00.0000
721 -enable-libgc Use the Bohem memory allocator.
722 Lower runtime footprint.
725 Furthermore the environment variables CC, CFLAGS, ...
726 the tools and their arguments can be influenced.
727 Please see `configure -
737 -help` and the man/info pages of `configure` for details.
741 The names of the standard libraries STD_LIB, STD_INT_LIB, STD_LONG_LIB,
742 STD_FP_LIB, STD_DS390_LIB, STD_XA51_LIB and the environment variables SDCC_DIR_
743 NAME, SDCC_INCLUDE_NAME, SDCC_LIB_NAME are defined by `configure` too.
744 At the moment it's not possible to change the default settings (it was
745 simply never required.
749 These configure options are compiled into the binaries, and can only be
750 changed by rerunning 'configure' and recompiling SDCC.
751 The configure options are written in
755 to distinguish them from run time environment variables (see section search
761 \begin_inset Quotes sld
765 \begin_inset Quotes srd
768 are used by the SDCC team to build the official Win32 binaries.
769 The SDCC team uses Mingw32 to build the official Windows binaries, because
776 a gcc compiler and last but not least
779 the binaries can be built by cross compiling on Sourceforge's compile farm.
782 See the examples, how to pass the Win32 settings to 'configure'.
783 The other Win32 builds using Borland, VC or whatever don't use 'configure',
784 but a header file sdcc_vc_in.h is the same as sdccconf.h built by 'configure'
795 <lyxtabular version="3" rows="8" columns="3">
797 <column alignment="block" valignment="top" leftline="true" width="0in">
798 <column alignment="block" valignment="top" leftline="true" width="0in">
799 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
800 <row topline="true" bottomline="true">
801 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
809 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
817 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
827 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
837 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
845 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
857 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
867 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
877 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
889 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
899 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
911 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
927 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
937 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
949 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
961 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
971 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
983 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
999 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1009 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1017 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1026 <row topline="true" bottomline="true">
1027 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1037 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1045 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1064 'configure' also computes relative paths.
1065 This is needed for full relocatability of a binary package and to complete
1066 search paths (see section search paths below):
1071 \begin_inset Tabular
1072 <lyxtabular version="3" rows="4" columns="3">
1074 <column alignment="block" valignment="top" leftline="true" width="0in">
1075 <column alignment="block" valignment="top" leftline="true" width="0in">
1076 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1077 <row topline="true" bottomline="true">
1078 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1086 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1094 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1103 <row topline="true" bottomline="true">
1104 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1114 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1122 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1133 <row bottomline="true">
1134 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1144 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1152 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1161 <row bottomline="true">
1162 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1172 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1180 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1212 \begin_inset Quotes srd
1216 \begin_inset Quotes srd
1230 \begin_inset Quotes srd
1234 \begin_inset Quotes srd
1262 To cross compile on linux for Mingw32 (see also 'sdcc/support/scripts/sdcc_mingw
1271 \begin_inset Quotes srd
1274 i586-mingw32msvc-gcc
1275 \begin_inset Quotes srd
1279 \begin_inset Quotes srd
1282 i586-mingw32msvc-g++
1283 \begin_inset Quotes srd
1291 \begin_inset Quotes srd
1294 i586-mingw32msvc-ranlib
1295 \begin_inset Quotes srd
1303 \begin_inset Quotes srd
1306 i586-mingw32msvc-strip
1307 \begin_inset Quotes srd
1325 \begin_inset Quotes srd
1329 \begin_inset Quotes srd
1347 \begin_inset Quotes srd
1351 \begin_inset Quotes srd
1359 \begin_inset Quotes srd
1363 \begin_inset Quotes srd
1371 \begin_inset Quotes srd
1375 \begin_inset Quotes srd
1383 \begin_inset Quotes srd
1387 \begin_inset Quotes srd
1394 sdccconf_h_dir_separator=
1395 \begin_inset Quotes srd
1407 \begin_inset Quotes srd
1424 -disable-device-lib-build
1452 -host=i586-mingw32msvc -
1462 -build=unknown-unknown-linux-gnu
1466 \begin_inset Quotes sld
1470 \begin_inset Quotes srd
1473 compile on Cygwin for Mingw32(see also sdcc/support/scripts/sdcc_cygwin_mingw32)
1482 \begin_inset Quotes srd
1486 \begin_inset Quotes srd
1494 \begin_inset Quotes srd
1498 \begin_inset Quotes srd
1516 \begin_inset Quotes srd
1520 \begin_inset Quotes srd
1538 \begin_inset Quotes srd
1542 \begin_inset Quotes srd
1550 \begin_inset Quotes srd
1554 \begin_inset Quotes srd
1562 \begin_inset Quotes srd
1566 \begin_inset Quotes srd
1574 \begin_inset Quotes srd
1578 \begin_inset Quotes srd
1585 sdccconf_h_dir_separator=
1586 \begin_inset Quotes srd
1598 \begin_inset Quotes srd
1618 'configure' is quite slow on Cygwin (at least on windows before Win2000/XP).
1629 -C' turns on caching, which gives a little bit extra speed.
1630 However if options are changed, it can be necessary to delete the config.cache
1635 \begin_inset LatexCommand \index{Install paths}
1643 Binary files (preprocessor, assembler and linker)
1647 \begin_inset Tabular
1648 <lyxtabular version="3" rows="2" columns="3">
1650 <column alignment="block" valignment="top" leftline="true" width="0in">
1651 <column alignment="block" valignment="top" leftline="true" width="0in">
1652 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1653 <row topline="true" bottomline="true">
1654 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1662 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1670 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1679 <row topline="true" bottomline="true">
1680 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1690 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1698 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1724 \begin_inset Tabular
1725 <lyxtabular version="3" rows="2" columns="3">
1727 <column alignment="block" valignment="top" leftline="true" width="1.6in">
1728 <column alignment="block" valignment="top" leftline="true" width="0in">
1729 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1730 <row topline="true" bottomline="true">
1731 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1739 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1747 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1756 <row topline="true" bottomline="true">
1757 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1769 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1774 /usr/local/share/sdcc/include
1777 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1803 is auto-appended by the compiler, e.g.
1804 small, large, z80, ds390 etc.)
1808 \begin_inset Tabular
1809 <lyxtabular version="3" rows="2" columns="3">
1811 <column alignment="block" valignment="top" leftline="true" width="0in">
1812 <column alignment="block" valignment="top" leftline="true" width="0in">
1813 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1814 <row topline="true" bottomline="true">
1815 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1823 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1831 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1840 <row topline="true" bottomline="true">
1841 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1848 $DATADIR/$LIB_DIR_SUFFIX
1851 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1856 /usr/local/share/sdcc/lib
1859 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1885 \begin_inset Tabular
1886 <lyxtabular version="3" rows="2" columns="3">
1888 <column alignment="block" valignment="top" leftline="true" width="0in">
1889 <column alignment="block" valignment="top" leftline="true" width="0in">
1890 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1891 <row topline="true" bottomline="true">
1892 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1900 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1908 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1917 <row topline="true" bottomline="true">
1918 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1928 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1933 /usr/local/share/sdcc/doc
1936 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1957 The install paths can still be changed during `make install` with e.g.:
1960 make install prefix=$(HOME)/local/sdcc
1963 Of course this doesn't change the search paths compiled into the binaries.
1967 \begin_inset LatexCommand \index{Search path}
1974 Some search paths or parts of them are determined by configure variables
1979 , see section above).
1980 Further search paths are determined by environment variables during runtime.
1983 The paths searched when running the compiler are as follows (the first catch
1989 Binary files (preprocessor, assembler and linker)
1992 \begin_inset Tabular
1993 <lyxtabular version="3" rows="4" columns="3">
1995 <column alignment="block" valignment="top" leftline="true" width="0in">
1996 <column alignment="block" valignment="top" leftline="true" width="0in">
1997 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1998 <row topline="true" bottomline="true">
1999 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2007 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2015 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2024 <row topline="true">
2025 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2035 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2043 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2054 <row topline="true">
2055 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2060 Path of argv[0] (if available)
2063 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2071 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2080 <row topline="true" bottomline="true">
2081 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2089 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2097 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2118 \begin_inset Tabular
2119 <lyxtabular version="3" rows="6" columns="3">
2121 <column alignment="block" valignment="top" leftline="true" width="1.5in">
2122 <column alignment="block" valignment="top" leftline="true" width="1.5in">
2123 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
2124 <row topline="true" bottomline="true">
2125 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2133 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2141 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2150 <row topline="true">
2151 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2169 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2187 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2206 <row topline="true">
2207 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2215 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2223 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2232 <row topline="true">
2233 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2247 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2259 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2270 <row topline="true">
2271 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2289 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2339 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2352 <row topline="true" bottomline="true">
2353 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2369 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2374 /usr/local/share/sdcc/
2379 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2406 -nostdinc disables the last two search paths.
2413 With the exception of
2414 \begin_inset Quotes sld
2428 \begin_inset Quotes srd
2435 is auto-appended by the compiler (e.g.
2436 small, large, z80, ds390 etc.).
2440 \begin_inset Tabular
2441 <lyxtabular version="3" rows="6" columns="3">
2443 <column alignment="block" valignment="top" leftline="true" width="1.7in">
2444 <column alignment="block" valignment="top" leftline="true" width="1.2in">
2445 <column alignment="block" valignment="top" leftline="true" rightline="true" width="1.2in">
2446 <row topline="true" bottomline="true">
2447 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2455 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2463 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2472 <row topline="true">
2473 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2491 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2509 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2528 <row topline="true">
2529 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2541 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2553 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2568 <row topline="true">
2569 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2580 $LIB_DIR_SUFFIX/<model>
2583 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2597 <cell alignment="left" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2614 <row topline="true">
2615 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2630 $LIB_DIR_SUFFIX/<model>
2633 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2686 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2742 <row topline="true" bottomline="true">
2743 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2752 $LIB_DIR_SUFFIX/<model>
2755 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2760 /usr/local/share/sdcc/
2767 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2783 Don't delete any of the stray spaces in the table above without checking
2784 the HTML output (last line)!
2800 -nostdlib disables the last two search paths.
2804 \begin_inset LatexCommand \index{Building SDCC}
2809 \layout Subsubsection
2811 Building SDCC on Linux
2816 Download the source package
2818 either from the SDCC CVS repository or from the
2819 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
2825 , it will be named something like sdcc
2838 Bring up a command line terminal, such as xterm.
2843 Unpack the file using a command like:
2846 "tar -xzf sdcc.src.tar.gz
2851 , this will create a sub-directory called sdcc with all of the sources.
2854 Change directory into the main SDCC directory, for example type:
2871 This configures the package for compilation on your system.
2887 All of the source packages will compile, this can take a while.
2903 This copies the binary executables, the include files, the libraries and
2904 the documentation to the install directories.
2905 \layout Subsubsection
2907 Building SDCC on OSX 2.x
2910 Follow the instruction for Linux.
2914 On OSX 2.x it was reported, that the default gcc (version 3.1 20020420 (prerelease
2915 )) fails to compile SDCC.
2916 Fortunately there's also gcc 2.9.x installed, which works fine.
2917 This compiler can be selected by running 'configure' with:
2920 ./configure CC=gcc2 CXX=g++2
2921 \layout Subsubsection
2923 Cross compiling SDCC on Linux for Windows
2926 With the Mingw32 gcc cross compiler it's easy to compile SDCC for Win32.
2927 See section 'Configure Options'.
2928 \layout Subsubsection
2930 Building SDCC on Windows
2933 With the exception of Cygwin the SDCC binaries uCsim and sdcdb can't be
2935 They use Unix-sockets, which are not available on Win32.
2936 \layout Subsubsection
2938 Windows Install Using a Binary Package
2941 Download the binary package and unpack it using your favorite unpacking
2942 tool (gunzip, WinZip, etc).
2943 This should unpack to a group of sub-directories.
2944 An example directory structure after unpacking the mingw32 package is:
2949 bin for the executables, c:
2957 lib for the include and libraries.
2960 Adjust your environment variable PATH to include the location of the bin
2961 directory or start sdcc using the full path.
2962 \layout Subsubsection
2964 Building SDCC using Cygwin and Mingw32
2967 For building and installing a Cygwin executable follow the instructions
2973 \begin_inset Quotes sld
2977 \begin_inset Quotes srd
2980 Win32-binary can be built, which will not need the Cygwin-DLL.
2981 For the necessary 'configure' options see section 'configure options' or
2982 the script 'sdcc/support/scripts/sdcc_cygwinmingw32'.
2986 In order to install Cygwin on Windows download setup.exe from
2987 \begin_inset LatexCommand \url[www.cygwin.com]{http://www.cygwin.com/}
2993 \begin_inset Quotes sld
2996 default text file type
2997 \begin_inset Quotes srd
3001 \begin_inset Quotes sld
3005 \begin_inset Quotes srd
3008 and download/install at least the following packages.
3009 Some packages are selected by default, others will be automatically selected
3010 because of dependencies with the manually selected packages.
3011 Never deselect these packages!
3020 gcc ; version 3.x is fine, no need to use the old 2.9x
3023 binutils ; selected with gcc
3029 rxvt ; a nice console, which makes life much easier under windoze (see below)
3032 man ; not really needed for building SDCC, but you'll miss it sooner or
3036 less ; not really needed for building SDCC, but you'll miss it sooner or
3040 cvs ; only if you use CVS access
3043 If you want to develop something you'll need:
3046 python ; for the regression tests
3049 gdb ; the gnu debugger, together with the nice GUI
3050 \begin_inset Quotes sld
3054 \begin_inset Quotes srd
3060 openssh ; to access the CF or commit changes
3063 autoconf and autoconf-devel ; if you want to fight with 'configure', don't
3064 use autoconf-stable!
3067 rxvt is a nice console with history.
3068 Replace in your cygwin.bat the line
3087 rxvt -sl 1000 -fn "Lucida Console-12" -sr -cr red
3090 -bg black -fg white -geometry 100x65 -e bash -
3103 Text selected with the mouse is automatically copied to the clipboard, pasting
3104 works with shift-insert.
3108 The other good tip is to make sure you have no //c/-style paths anywhere,
3109 use /cygdrive/c/ instead.
3110 Using // invokes a network lookup which is very slow.
3112 \begin_inset Quotes sld
3116 \begin_inset Quotes srd
3119 is too long, you can change it with e.g.
3125 SDCC sources use the unix line ending LF.
3126 Life is much easier, if you store the source tree on a drive, which is
3127 mount in binary mode.
3128 And use an editor which can handle LF-only line endings.
3129 Make sure not to commit files with windows line endings.
3130 \layout Subsubsection
3132 Building SDCC Using Microsoft Visual C++ 6.0/NET (MSVC)
3137 Download the source package
3139 either from the SDCC CVS repository or from the
3140 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
3146 , it will be named something like sdcc
3153 SDCC is distributed with all the projects, workspaces, and files you need
3154 to build it using Visual C++ 6.0/NET (except for sdcdb.exe which currently
3155 doesn't build under MSVC).
3156 The workspace name is 'sdcc.dsw'.
3157 Please note that as it is now, all the executables are created in a folder
3161 Once built you need to copy the executables from sdcc
3165 bin before running SDCC.
3170 In order to build SDCC with MSVC you need win32 executables of bison.exe,
3171 flex.exe, and gawk.exe.
3172 One good place to get them is
3173 \begin_inset LatexCommand \url[here]{http://unxutils.sourceforge.net}
3181 Download the file UnxUtils
3182 \begin_inset LatexCommand \index{UnxUtils}
3187 Now you have to install the utilities and setup MSVC so it can locate the
3189 Here there are two alternatives (choose one!):
3196 a) Extract UnxUtils.zip to your C:
3198 hard disk PRESERVING the original paths, otherwise bison won't work.
3199 (If you are using WinZip make certain that 'Use folder names' is selected)
3203 b) In the Visual C++ IDE click Tools, Options, select the Directory tab,
3204 in 'Show directories for:' select 'Executable files', and in the directories
3205 window add a new path: 'C:
3215 (As a side effect, you get a bunch of Unix utilities that could be useful,
3216 such as diff and patch.)
3223 This one avoids extracting a bunch of files you may not use, but requires
3228 a) Create a directory were to put the tools needed, or use a directory already
3236 b) Extract 'bison.exe', 'bison.hairy', 'bison.simple', 'flex.exe', and gawk.exe
3237 to such directory WITHOUT preserving the original paths.
3238 (If you are using WinZip make certain that 'Use folder names' is not selected)
3242 c) Rename bison.exe to '_bison.exe'.
3246 d) Create a batch file 'bison.bat' in 'C:
3250 ' and add these lines:
3270 _bison %1 %2 %3 %4 %5 %6 %7 %8 %9
3274 Steps 'c' and 'd' are needed because bison requires by default that the
3275 files 'bison.simple' and 'bison.hairy' reside in some weird Unix directory,
3276 '/usr/local/share/' I think.
3277 So it is necessary to tell bison where those files are located if they
3278 are not in such directory.
3279 That is the function of the environment variables BISON_SIMPLE and BISON_HAIRY.
3283 e) In the Visual C++ IDE click Tools, Options, select the Directory tab,
3284 in 'Show directories for:' select 'Executable files', and in the directories
3285 window add a new path: 'c:
3288 Note that you can use any other path instead of 'c:
3290 util', even the path where the Visual C++ tools are, probably: 'C:
3294 Microsoft Visual Studio
3299 So you don't have to execute step 'e' :)
3303 Open 'sdcc.dsw' in Visual Studio, click 'build all', when it finishes copy
3304 the executables from sdcc
3308 bin, and you can compile using sdcc.
3309 \layout Subsubsection
3311 Building SDCC Using Borland
3314 From the sdcc directory, run the command "make -f Makefile.bcc".
3315 This should regenerate all the .exe files in the bin directory except for
3316 sdcdb.exe (which currently doesn't build under Borland C++).
3319 If you modify any source files and need to rebuild, be aware that the dependenci
3320 es may not be correctly calculated.
3321 The safest option is to delete all .obj files and run the build again.
3322 From a Cygwin BASH prompt, this can easily be done with the command:
3332 ( -name '*.obj' -o -name '*.lib' -o -name '*.rul'
3334 ) -print -exec rm {}
3343 or on Windows NT/2000/XP from the command prompt with the command:
3350 del /s *.obj *.lib *.rul
3353 from the sdcc directory.
3356 Building the Documentation
3363 Testing out the SDCC Compiler
3366 The first thing you should do after installing your SDCC compiler is to
3382 \begin_inset LatexCommand \index{version}
3389 at the prompt, and the program should run and tell you the version.
3390 If it doesn't run, or gives a message about not finding sdcc program, then
3391 you need to check over your installation.
3392 Make sure that the sdcc bin directory is in your executable search path
3393 defined by the PATH environment setting (see the Trouble-shooting section
3395 Make sure that the sdcc program is in the bin folder, if not perhaps something
3396 did not install correctly.
3404 is commonly installed as described in section
3405 \begin_inset Quotes sld
3408 Install and search paths
3409 \begin_inset Quotes srd
3418 Make sure the compiler works on a very simple example.
3419 Type in the following test.c program using your favorite
3445 Compile this using the following command:
3454 If all goes well, the compiler will generate a test.asm and test.rel file.
3455 Congratulations, you've just compiled your first program with SDCC.
3456 We used the -c option to tell SDCC not to link the generated code, just
3457 to keep things simple for this step.
3465 The next step is to try it with the linker.
3475 If all goes well the compiler will link with the libraries and produce
3476 a test.ihx output file.
3481 (no test.ihx, and the linker generates warnings), then the problem is most
3482 likely that sdcc cannot find the
3486 usr/local/share/sdcc/lib directory
3490 (see the Install trouble-shooting section for suggestions).
3498 The final test is to ensure sdcc can use the
3502 header files and libraries.
3503 Edit test.c and change it to the following:
3520 strcpy(str1, "testing");
3527 Compile this by typing
3534 This should generate a test.ihx output file, and it should give no warnings
3535 such as not finding the string.h file.
3536 If it cannot find the string.h file, then the problem is that sdcc cannot
3537 find the /usr/local/share/sdcc/include directory
3541 (see the Install trouble-shooting section for suggestions).
3544 To find exactly where SDCC is looking for the include files try compiling
3552 \begin_inset LatexCommand \index{-V}
3559 Install Trouble-shooting
3560 \begin_inset LatexCommand \index{Install trouble-shooting}
3565 \layout Subsubsection
3567 SDCC does not build correctly.
3570 A thing to try is starting from scratch by unpacking the .tgz source package
3571 again in an empty directory.
3579 ./configure 2>&1 | tee configure.log
3593 make 2>&1 | tee make.log
3600 If anything goes wrong, you can review the log files to locate the problem.
3601 Or a relevant part of this can be attached to an email that could be helpful
3602 when requesting help from the mailing list.
3603 \layout Subsubsection
3606 \begin_inset Quotes sld
3610 \begin_inset Quotes srd
3617 \begin_inset Quotes sld
3621 \begin_inset Quotes srd
3624 command is a script that analyzes your system and performs some configuration
3625 to ensure the source package compiles on your system.
3626 It will take a few minutes to run, and will compile a few tests to determine
3627 what compiler features are installed.
3628 \layout Subsubsection
3631 \begin_inset Quotes sld
3635 \begin_inset Quotes srd
3641 This runs the GNU make tool, which automatically compiles all the source
3642 packages into the final installed binary executables.
3643 \layout Subsubsection
3646 \begin_inset Quotes sld
3650 \begin_inset Quotes erd
3656 This will install the compiler, other executables libraries and include
3657 files in to the appropriate directories.
3659 \begin_inset Quotes sld
3662 Install and Search PATHS
3663 \begin_inset Quotes srd
3668 On most systems you will need super-user privileges to do this.
3674 SDCC is not just a compiler, but a collection of tools by various developers.
3675 These include linkers, assemblers, simulators and other components.
3676 Here is a summary of some of the components.
3677 Note that the included simulator and assembler have separate documentation
3678 which you can find in the source package in their respective directories.
3679 As SDCC grows to include support for other processors, other packages from
3680 various developers are included and may have their own sets of documentation.
3684 You might want to look at the files which are installed in <installdir>.
3685 At the time of this writing, we find the following programs for gcc-builds:
3689 In <installdir>/bin:
3692 sdcc - The compiler.
3695 sdcpp - The C preprocessor.
3698 asx8051 - The assembler for 8051 type processors.
3705 as-gbz80 - The Z80 and GameBoy Z80 assemblers.
3708 aslink -The linker for 8051 type processors.
3715 link-gbz80 - The Z80 and GameBoy Z80 linkers.
3718 s51 - The ucSim 8051 simulator.
3721 sdcdb - The source debugger.
3724 packihx - A tool to pack (compress) Intel hex files.
3727 In <installdir>/share/sdcc/include
3733 In <installdir>/share/sdcc/lib
3736 the subdirs src and small, large, z80, gbz80 and ds390 with the precompiled
3740 In <installdir>/share/sdcc/doc
3746 As development for other processors proceeds, this list will expand to include
3747 executables to support processors like AVR, PIC, etc.
3748 \layout Subsubsection
3753 This is the actual compiler, it in turn uses the c-preprocessor and invokes
3754 the assembler and linkage editor.
3755 \layout Subsubsection
3758 \begin_inset LatexCommand \index{sdcpp}
3762 - The C-Preprocessor
3765 The preprocessor is a modified version of the GNU preprocessor.
3766 The C preprocessor is used to pull in #include sources, process #ifdef
3767 statements, #defines and so on.
3768 \layout Subsubsection
3770 asx8051, as-z80, as-gbz80, aslink, link-z80, link-gbz80 - The Assemblers
3774 This is retargettable assembler & linkage editor, it was developed by Alan
3776 John Hartman created the version for 8051, and I (Sandeep) have made some
3777 enhancements and bug fixes for it to work properly with the SDCC.
3778 \layout Subsubsection
3781 \begin_inset LatexCommand \index{s51}
3788 S51 is a freeware, opensource simulator developed by Daniel Drotos (
3789 \begin_inset LatexCommand \url{mailto:drdani@mazsola.iit.uni-miskolc.hu}
3794 The simulator is built as part of the build process.
3795 For more information visit Daniel's web site at:
3796 \begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
3801 It currently support the core mcs51, the Dallas DS80C390 and the Phillips
3803 \layout Subsubsection
3806 \begin_inset LatexCommand \index{sdcdb}
3810 - Source Level Debugger
3813 Sdcdb is the companion source level debugger.
3814 The current version of the debugger uses Daniel's Simulator S51, but can
3815 be easily changed to use other simulators.
3822 \layout Subsubsection
3824 Single Source File Projects
3827 For single source file 8051 projects the process is very simple.
3828 Compile your programs with the following command
3831 "sdcc sourcefile.c".
3835 This will compile, assemble and link your source file.
3836 Output files are as follows
3840 \begin_inset LatexCommand \index{.asm}
3845 \begin_inset LatexCommand \index{Assembler source}
3849 file created by the compiler
3853 \begin_inset LatexCommand \index{.lst}
3858 \begin_inset LatexCommand \index{Assembler listing}
3862 file created by the Assembler
3866 \begin_inset LatexCommand \index{.rst}
3871 \begin_inset LatexCommand \index{Assembler listing}
3875 file updated with linkedit information, created by linkage editor
3879 \begin_inset LatexCommand \index{.sym}
3884 \begin_inset LatexCommand \index{Symbol listing}
3888 for the sourcefile, created by the assembler
3892 \begin_inset LatexCommand \index{.rel}
3897 \begin_inset LatexCommand \index{Object file}
3901 created by the assembler, input to Linkage editor
3905 \begin_inset LatexCommand \index{.map}
3910 \begin_inset LatexCommand \index{Memory map}
3914 for the load module, created by the Linker
3918 \begin_inset LatexCommand \index{.mem}
3922 - A file with a summary of the memory usage
3926 \begin_inset LatexCommand \index{.ihx}
3930 - The load module in Intel hex format
3931 \begin_inset LatexCommand \index{Intel hex format}
3935 (you can select the Motorola S19 format
3936 \begin_inset LatexCommand \index{Motorola S19 format}
3951 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
3956 If you need another format you might want to use objdump
3957 \begin_inset LatexCommand \index{objdump}
3962 \begin_inset LatexCommand \index{srecord}
3970 \begin_inset LatexCommand \index{.adb}
3974 - An intermediate file containing debug information needed to create the
3986 \begin_inset LatexCommand \index{-\/-debug}
3994 \begin_inset LatexCommand \index{.cdb}
3998 - An optional file (with -
4008 -debug) containing debug information
4013 \begin_inset LatexCommand \index{. (no extension)}
4017 An optional AOMF51 file containing debug information (with -
4031 \begin_inset LatexCommand \index{.dump*}
4035 - Dump file to debug the compiler it self (with -
4045 -dumpall) (see section
4046 \begin_inset Quotes sld
4049 Anatomy of the compiler
4050 \begin_inset Quotes srd
4054 \layout Subsubsection
4056 Projects with Multiple Source Files
4059 SDCC can compile only ONE file at a time.
4060 Let us for example assume that you have a project containing the following
4065 foo1.c (contains some functions)
4067 foo2.c (contains some more functions)
4069 foomain.c (contains more functions and the function main)
4077 The first two files will need to be compiled separately with the commands:
4109 Then compile the source file containing the
4114 \begin_inset LatexCommand \index{Linker}
4118 the files together with the following command:
4126 foomain.c\SpecialChar ~
4127 foo1.rel\SpecialChar ~
4132 \begin_inset LatexCommand \index{.rel}
4144 can be separately compiled as well:
4155 sdcc foomain.rel foo1.rel foo2.rel
4162 The file containing the
4177 file specified in the command line, since the linkage editor processes
4178 file in the order they are presented to it.
4179 The linker is invoked from sdcc using a script file with extension .lnk
4180 \begin_inset LatexCommand \index{.lnk}
4185 You can view this file to troubleshoot linking problems such as those arising
4186 from missing libraries.
4187 \layout Subsubsection
4189 Projects with Additional Libraries
4190 \begin_inset LatexCommand \index{Libraries}
4197 Some reusable routines may be compiled into a library, see the documentation
4198 for the assembler and linkage editor (which are in <installdir>/share/sdcc/doc)
4202 \begin_inset LatexCommand \index{.lib}
4209 Libraries created in this manner can be included in the command line.
4210 Make sure you include the -L <library-path> option to tell the linker where
4211 to look for these files if they are not in the current directory.
4212 Here is an example, assuming you have the source file
4224 (if that is not the same as your current project):
4231 sdcc foomain.c foolib.lib -L mylib
4242 must be an absolute path name.
4246 The most efficient way to use libraries is to keep separate modules in separate
4248 The lib file now should name all the modules.rel
4249 \begin_inset LatexCommand \index{rel}
4254 For an example see the standard library file
4258 in the directory <installdir>/share/lib/small.
4261 Command Line Options
4262 \begin_inset LatexCommand \index{Command Line Options}
4267 \layout Subsubsection
4269 Processor Selection Options
4270 \begin_inset LatexCommand \index{Options processor selection}
4275 \begin_inset LatexCommand \index{Processor selection options}
4281 \labelwidthstring 00.00.0000
4286 \begin_inset LatexCommand \index{-mmcs51}
4292 Generate code for the MCS51
4293 \begin_inset LatexCommand \index{MCS51}
4297 family of processors.
4298 This is the default processor target.
4300 \labelwidthstring 00.00.0000
4305 \begin_inset LatexCommand \index{-mds390}
4311 Generate code for the DS80C390
4312 \begin_inset LatexCommand \index{DS80C390}
4318 \labelwidthstring 00.00.0000
4323 \begin_inset LatexCommand \index{-mds400}
4329 Generate code for the DS80C400
4330 \begin_inset LatexCommand \index{DS80C400}
4336 \labelwidthstring 00.00.0000
4341 \begin_inset LatexCommand \index{-mz80}
4347 Generate code for the Z80
4348 \begin_inset LatexCommand \index{Z80}
4352 family of processors.
4354 \labelwidthstring 00.00.0000
4359 \begin_inset LatexCommand \index{-mgbz80}
4365 Generate code for the GameBoy Z80
4366 \begin_inset LatexCommand \index{GameBoy Z80}
4372 \labelwidthstring 00.00.0000
4377 \begin_inset LatexCommand \index{-mavr}
4383 Generate code for the Atmel AVR
4384 \begin_inset LatexCommand \index{AVR}
4388 processor (In development, not complete).
4389 AVR users should probably have a look at avr-gcc
4390 \begin_inset LatexCommand \url[FIXME: official URL?]{ http://savannah.nongnu.org/download/avr-libc/snapshots/}
4397 I think it is fair to direct users there for now.
4398 Open source is also about avoiding unnecessary work .
4399 But I didn't find the 'official' link.
4401 \labelwidthstring 00.00.0000
4406 \begin_inset LatexCommand \index{-mpic14}
4412 Generate code for the PIC 14
4413 \begin_inset LatexCommand \index{PIC14}
4417 -bit processors (In development, not complete).
4420 p16f627 p16f628 p16f84 p16f873 p16f877?
4422 \labelwidthstring 00.00.0000
4428 Generate code for the Toshiba TLCS-900H
4429 \begin_inset LatexCommand \index{TLCS-900H}
4433 processor (In development, not complete).
4435 \labelwidthstring 00.00.0000
4440 \begin_inset LatexCommand \index{-mxa51}
4446 Generate code for the Phillips XA51
4447 \begin_inset LatexCommand \index{XA51}
4451 processor (In development, not complete).
4452 \layout Subsubsection
4454 Preprocessor Options
4455 \begin_inset LatexCommand \index{Options preprocessor}
4460 \begin_inset LatexCommand \index{Preprocessor options}
4466 \labelwidthstring 00.00.0000
4471 \begin_inset LatexCommand \index{-I<path>}
4477 The additional location where the pre processor will look for <..h> or
4478 \begin_inset Quotes eld
4482 \begin_inset Quotes erd
4487 \labelwidthstring 00.00.0000
4492 \begin_inset LatexCommand \index{-D<macro[=value]>}
4498 Command line definition of macros.
4499 Passed to the pre processor.
4501 \labelwidthstring 00.00.0000
4506 \begin_inset LatexCommand \index{-M}
4512 Tell the preprocessor to output a rule suitable for make describing the
4513 dependencies of each object file.
4514 For each source file, the preprocessor outputs one make-rule whose target
4515 is the object file name for that source file and whose dependencies are
4516 all the files `#include'd in it.
4517 This rule may be a single line or may be continued with `
4519 '-newline if it is long.
4520 The list of rules is printed on standard output instead of the preprocessed
4524 \labelwidthstring 00.00.0000
4529 \begin_inset LatexCommand \index{-C}
4535 Tell the preprocessor not to discard comments.
4536 Used with the `-E' option.
4538 \labelwidthstring 00.00.0000
4543 \begin_inset LatexCommand \index{-MM}
4554 Like `-M' but the output mentions only the user header files included with
4556 \begin_inset Quotes eld
4560 System header files included with `#include <file>' are omitted.
4562 \labelwidthstring 00.00.0000
4567 \begin_inset LatexCommand \index{-Aquestion(answer)}
4573 Assert the answer answer for question, in case it is tested with a preprocessor
4574 conditional such as `#if #question(answer)'.
4575 `-A-' disables the standard assertions that normally describe the target
4578 \labelwidthstring 00.00.0000
4584 (answer) Assert the answer answer for question, in case it is tested with
4585 a preprocessor conditional such as `#if #question(answer)'.
4586 `-A-' disables the standard assertions that normally describe the target
4589 \labelwidthstring 00.00.0000
4594 \begin_inset LatexCommand \index{-Umacro}
4600 Undefine macro macro.
4601 `-U' options are evaluated after all `-D' options, but before any `-include'
4602 and `-imacros' options.
4604 \labelwidthstring 00.00.0000
4609 \begin_inset LatexCommand \index{-dM}
4615 Tell the preprocessor to output only a list of the macro definitions that
4616 are in effect at the end of preprocessing.
4617 Used with the `-E' option.
4619 \labelwidthstring 00.00.0000
4624 \begin_inset LatexCommand \index{-dD}
4630 Tell the preprocessor to pass all macro definitions into the output, in
4631 their proper sequence in the rest of the output.
4633 \labelwidthstring 00.00.0000
4638 \begin_inset LatexCommand \index{-dN}
4649 Like `-dD' except that the macro arguments and contents are omitted.
4650 Only `#define name' is included in the output.
4651 \layout Subsubsection
4654 \begin_inset LatexCommand \index{Options linker}
4659 \begin_inset LatexCommand \index{Linker options}
4665 \labelwidthstring 00.00.0000
4685 \begin_inset LatexCommand \index{-\/-lib-path}
4690 \begin_inset LatexCommand \index{-L -\/-lib-path}
4699 <absolute path to additional libraries> This option is passed to the linkage
4700 editor's additional libraries
4701 \begin_inset LatexCommand \index{Libraries}
4706 The path name must be absolute.
4707 Additional library files may be specified in the command line.
4708 See section Compiling programs for more details.
4710 \labelwidthstring 00.00.0000
4727 \begin_inset LatexCommand \index{-\/-xram-loc}
4731 <Value> The start location of the external ram
4732 \begin_inset LatexCommand \index{xdata}
4736 , default value is 0.
4737 The value entered can be in Hexadecimal or Decimal format, e.g.: -
4747 -xram-loc 0x8000 or -
4759 \labelwidthstring 00.00.0000
4776 \begin_inset LatexCommand \index{-\/-code-loc}
4780 <Value> The start location of the code
4781 \begin_inset LatexCommand \index{code}
4785 segment, default value 0.
4786 Note when this option is used the interrupt vector table is also relocated
4787 to the given address.
4788 The value entered can be in Hexadecimal or Decimal format, e.g.: -
4798 -code-loc 0x8000 or -
4810 \labelwidthstring 00.00.0000
4827 \begin_inset LatexCommand \index{-\/-stack-loc}
4831 <Value> By default the stack
4832 \begin_inset LatexCommand \index{stack}
4836 is placed after the data segment.
4837 Using this option the stack can be placed anywhere in the internal memory
4839 The value entered can be in Hexadecimal or Decimal format, e.g.
4850 -stack-loc 0x20 or -
4861 Since the sp register is incremented before a push or call, the initial
4862 sp will be set to one byte prior the provided value.
4863 The provided value should not overlap any other memory areas such as used
4864 register banks or the data segment and with enough space for the current
4867 \labelwidthstring 00.00.0000
4884 \begin_inset LatexCommand \index{-\/-data-loc}
4888 <Value> The start location of the internal ram data
4889 \begin_inset LatexCommand \index{data}
4894 The value entered can be in Hexadecimal or Decimal format, eg.
4916 (By default, the start location of the internal ram data segment is set
4917 as low as possible in memory, taking into account the used register banks
4918 and the bit segment at address 0x20.
4919 For example if register banks 0 and 1 are used without bit variables, the
4920 data segment will be set, if -
4930 -data-loc is not used, to location 0x10.)
4932 \labelwidthstring 00.00.0000
4949 \begin_inset LatexCommand \index{-\/-idata-loc}
4953 <Value> The start location of the indirectly addressable internal ram
4954 \begin_inset LatexCommand \index{idata}
4958 , default value is 0x80.
4959 The value entered can be in Hexadecimal or Decimal format, eg.
4970 -idata-loc 0x88 or -
4982 \labelwidthstring 00.00.0000
4997 \begin_inset LatexCommand \index{-\/-out-fmt-ihx}
5006 The linker output (final object code) is in Intel Hex format.
5007 \begin_inset LatexCommand \index{Intel hex format}
5011 (This is the default option).
5013 \labelwidthstring 00.00.0000
5028 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
5037 The linker output (final object code) is in Motorola S19 format
5038 \begin_inset LatexCommand \index{Motorola S19 format}
5043 \layout Subsubsection
5046 \begin_inset LatexCommand \index{Options MCS51}
5051 \begin_inset LatexCommand \index{MCS51 options}
5057 \labelwidthstring 00.00.0000
5072 \begin_inset LatexCommand \index{-\/-model-large}
5078 Generate code for Large model programs see section Memory Models for more
5080 If this option is used all source files in the project should be compiled
5082 In addition the standard library routines are compiled with small model,
5083 they will need to be recompiled.
5085 \labelwidthstring 00.00.0000
5100 \begin_inset LatexCommand \index{-\/-model-small}
5111 Generate code for Small Model programs see section Memory Models for more
5113 This is the default model.
5114 \layout Subsubsection
5117 \begin_inset LatexCommand \index{Options DS390}
5122 \begin_inset LatexCommand \index{DS390 options}
5128 \labelwidthstring 00.00.0000
5145 \begin_inset LatexCommand \index{-\/-model-flat24}
5155 Generate 24-bit flat mode code.
5156 This is the one and only that the ds390 code generator supports right now
5157 and is default when using
5162 See section Memory Models for more details.
5164 \labelwidthstring 00.00.0000
5181 \begin_inset LatexCommand \index{-\/-stack-10bit}
5185 Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
5186 This is the one and only that the ds390 code generator supports right now
5187 and is default when using
5192 In this mode, the stack is located in the lower 1K of the internal RAM,
5193 which is mapped to 0x400000.
5194 Note that the support is incomplete, since it still uses a single byte
5195 as the stack pointer.
5196 This means that only the lower 256 bytes of the potential 1K stack space
5197 will actually be used.
5198 However, this does allow you to reclaim the precious 256 bytes of low RAM
5199 for use for the DATA and IDATA segments.
5200 The compiler will not generate any code to put the processor into 10 bit
5202 It is important to ensure that the processor is in this mode before calling
5203 any re-entrant functions compiled with this option.
5204 In principle, this should work with the
5217 \begin_inset LatexCommand \index{-\/-stack-auto}
5223 option, but that has not been tested.
5224 It is incompatible with the
5237 \begin_inset LatexCommand \index{-\/-xstack}
5244 It also only makes sense if the processor is in 24 bit contiguous addressing
5257 -model-flat24 option
5260 \layout Subsubsection
5262 Optimization Options
5263 \begin_inset LatexCommand \index{Options optimization}
5268 \begin_inset LatexCommand \index{Optimization options}
5274 \labelwidthstring 00.00.0000
5289 \begin_inset LatexCommand \index{-\/-nogcse}
5295 Will not do global subexpression elimination, this option may be used when
5296 the compiler creates undesirably large stack/data spaces to store compiler
5298 A warning message will be generated when this happens and the compiler
5299 will indicate the number of extra bytes it allocated.
5300 It recommended that this option NOT be used, #pragma\SpecialChar ~
5302 \begin_inset LatexCommand \index{\#pragma NOGCSE}
5306 can be used to turn off global subexpression elimination
5307 \begin_inset LatexCommand \index{Subexpression elimination}
5311 for a given function only.
5313 \labelwidthstring 00.00.0000
5328 \begin_inset LatexCommand \index{-\/-noinvariant}
5334 Will not do loop invariant optimizations, this may be turned off for reasons
5335 explained for the previous option.
5336 For more details of loop optimizations performed see section Loop Invariants.It
5337 recommended that this option NOT be used, #pragma\SpecialChar ~
5339 \begin_inset LatexCommand \index{\#pragma NOINVARIANT}
5343 can be used to turn off invariant optimizations for a given function only.
5345 \labelwidthstring 00.00.0000
5360 \begin_inset LatexCommand \index{-\/-noinduction}
5366 Will not do loop induction optimizations, see section strength reduction
5367 for more details.It is recommended that this option is NOT used, #pragma\SpecialChar ~
5370 \begin_inset LatexCommand \index{\#pragma NOINDUCTION}
5374 can be used to turn off induction optimizations for a given function only.
5376 \labelwidthstring 00.00.0000
5391 \begin_inset LatexCommand \index{-\/-nojtbound}
5402 Will not generate boundary condition check when switch statements
5403 \begin_inset LatexCommand \index{switch statement}
5407 are implemented using jump-tables.
5408 See section Switch Statements for more details.
5409 It is recommended that this option is NOT used, #pragma\SpecialChar ~
5411 \begin_inset LatexCommand \index{\#pragma NOJTBOUND}
5415 can be used to turn off boundary checking for jump tables for a given function
5418 \labelwidthstring 00.00.0000
5433 \begin_inset LatexCommand \index{-\/-noloopreverse}
5442 Will not do loop reversal
5443 \begin_inset LatexCommand \index{Loop reversing}
5449 \labelwidthstring 00.00.0000
5466 \begin_inset LatexCommand \index{-\/-nolabelopt }
5470 Will not optimize labels (makes the dumpfiles more readable).
5472 \labelwidthstring 00.00.0000
5487 \begin_inset LatexCommand \index{-\/-no-xinit-opt}
5493 Will not memcpy initialized data in far space from code space.
5494 This saves a few bytes in code space if you don't have initialized data.
5495 \layout Subsubsection
5498 \begin_inset LatexCommand \index{Options other}
5504 \labelwidthstring 00.00.0000
5520 \begin_inset LatexCommand \index{-\/-compile-only}
5525 \begin_inset LatexCommand \index{-c -\/-compile-only}
5531 will compile and assemble the source, but will not call the linkage editor.
5533 \labelwidthstring 00.00.0000
5552 \begin_inset LatexCommand \index{-\/-c1mode}
5558 reads the preprocessed source from standard input and compiles it.
5559 The file name for the assembler output must be specified using the -o option.
5561 \labelwidthstring 00.00.0000
5566 \begin_inset LatexCommand \index{-E}
5572 Run only the C preprocessor.
5573 Preprocess all the C source files specified and output the results to standard
5576 \labelwidthstring 00.00.0000
5582 \begin_inset LatexCommand \index{-o <path/file>}
5588 The output path resp.
5589 file where everything will be placed.
5590 If the parameter is a path, it must have a trailing slash (or backslash
5591 for the Windows binaries) to be recognized as a path.
5594 \labelwidthstring 00.00.0000
5609 \begin_inset LatexCommand \index{-\/-stack-auto}
5620 All functions in the source file will be compiled as
5625 \begin_inset LatexCommand \index{reentrant}
5630 the parameters and local variables will be allocated on the stack
5631 \begin_inset LatexCommand \index{stack}
5636 see section Parameters and Local Variables for more details.
5637 If this option is used all source files in the project should be compiled
5641 \labelwidthstring 00.00.0000
5656 \begin_inset LatexCommand \index{-\/-xstack}
5662 Uses a pseudo stack in the first 256 bytes in the external ram for allocating
5663 variables and passing parameters.
5664 See section on external stack for more details.
5666 \labelwidthstring 00.00.0000
5681 \begin_inset LatexCommand \index{-\/-callee-saves}
5686 \begin_inset LatexCommand \index{function prologue}
5690 function1[,function2][,function3]....
5693 The compiler by default uses a caller saves convention for register saving
5694 across function calls, however this can cause unnecessary register pushing
5695 & popping when calling small functions from larger functions.
5696 This option can be used to switch the register saving convention for the
5697 function names specified.
5698 The compiler will not save registers when calling these functions, no extra
5699 code will be generated at the entry & exit for these functions to save
5700 & restore the registers used by these functions, this can SUBSTANTIALLY
5701 reduce code & improve run time performance of the generated code.
5702 In the future the compiler (with inter procedural analysis) will be able
5703 to determine the appropriate scheme to use for each function call.
5704 DO NOT use this option for built-in functions such as _mulint..., if this
5705 option is used for a library function the appropriate library function
5706 needs to be recompiled with the same option.
5707 If the project consists of multiple source files then all the source file
5708 should be compiled with the same -
5718 -callee-saves option string.
5719 Also see #pragma\SpecialChar ~
5721 \begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
5727 \labelwidthstring 00.00.0000
5742 \begin_inset LatexCommand \index{-\/-debug}
5751 When this option is used the compiler will generate debug information, that
5752 can be used with the SDCDB.
5753 The debug information is collected in a file with .cdb extension.
5754 For more information see documentation for SDCDB.
5756 \labelwidthstring 00.00.0000
5773 \begin_inset LatexCommand \index{-\/-peep-file}
5777 <filename> This option can be used to use additional rules to be used by
5778 the peep hole optimizer.
5779 See section Peep Hole optimizations for details on how to write these rules.
5781 \labelwidthstring 00.00.0000
5786 \begin_inset LatexCommand \index{-S}
5797 Stop after the stage of compilation proper; do not assemble.
5798 The output is an assembler code file for the input file specified.
5800 \labelwidthstring 00.00.0000
5804 -Wa_asmOption[,asmOption]
5807 \begin_inset LatexCommand \index{-Wa\_asmOption[,asmOption]}
5812 Pass the asmOption to the assembler.
5814 \labelwidthstring 00.00.0000
5818 -Wl_linkOption[,linkOption]
5821 \begin_inset LatexCommand \index{-Wl\_linkOption[,linkOption]}
5826 Pass the linkOption to the linker.
5828 \labelwidthstring 00.00.0000
5843 \begin_inset LatexCommand \index{-\/-int-long-reent}
5849 Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
5850 Note by default these libraries are compiled as non-reentrant.
5851 See section Installation for more details.
5853 \labelwidthstring 00.00.0000
5868 \begin_inset LatexCommand \index{-\/-cyclomatic}
5877 This option will cause the compiler to generate an information message for
5878 each function in the source file.
5879 The message contains some
5883 information about the function.
5884 The number of edges and nodes the compiler detected in the control flow
5885 graph of the function, and most importantly the
5887 cyclomatic complexity
5888 \begin_inset LatexCommand \index{Cyclomatic complexity}
5894 see section on Cyclomatic Complexity for more details.
5896 \labelwidthstring 00.00.0000
5911 \begin_inset LatexCommand \index{-\/-float-reent}
5920 Floating point library is compiled as reentrant
5921 \begin_inset LatexCommand \index{reentrant}
5925 .See section Installation for more details.
5927 \labelwidthstring 00.00.0000
5942 \begin_inset LatexCommand \index{-\/-nooverlay}
5948 The compiler will not overlay parameters and local variables of any function,
5949 see section Parameters and local variables for more details.
5951 \labelwidthstring 00.00.0000
5966 \begin_inset LatexCommand \index{-\/-main-return}
5972 This option can be used when the code generated is called by a monitor
5974 The compiler will generate a 'ret' upon return from the 'main'
5975 \begin_inset LatexCommand \index{main return}
5980 The default option is to lock up i.e.
5983 \labelwidthstring 00.00.0000
5998 \begin_inset LatexCommand \index{-\/-no-peep}
6004 Disable peep-hole optimization.
6006 \labelwidthstring 00.00.0000
6021 \begin_inset LatexCommand \index{-\/-peep-asm}
6027 Pass the inline assembler code through the peep hole optimizer.
6028 This can cause unexpected changes to inline assembler code, please go through
6029 the peephole optimizer
6030 \begin_inset LatexCommand \index{Peephole optimizer}
6034 rules defined in the source file tree '<target>/peeph.def' before using
6037 \labelwidthstring 00.00.0000
6054 \begin_inset LatexCommand \index{-\/-iram-size<Value>}
6058 Causes the linker to check if the internal ram usage is within limits of
6061 \labelwidthstring 00.00.0000
6078 \begin_inset LatexCommand \index{-\/-xram-size<Value>}
6082 Causes the linker to check if the external ram usage is within limits of
6085 \labelwidthstring 00.00.0000
6102 \begin_inset LatexCommand \index{-\/-code-size<Value>}
6106 Causes the linker to check if the code usage is within limits of the given
6109 \labelwidthstring 00.00.0000
6124 \begin_inset LatexCommand \index{-\/-nostdincl}
6130 This will prevent the compiler from passing on the default include path
6131 to the preprocessor.
6133 \labelwidthstring 00.00.0000
6148 \begin_inset LatexCommand \index{-\/-nostdlib}
6154 This will prevent the compiler from passing on the default library
6155 \begin_inset LatexCommand \index{Libraries}
6161 \labelwidthstring 00.00.0000
6176 \begin_inset LatexCommand \index{-\/-verbose}
6182 Shows the various actions the compiler is performing.
6184 \labelwidthstring 00.00.0000
6189 \begin_inset LatexCommand \index{-V}
6195 Shows the actual commands the compiler is executing.
6197 \labelwidthstring 00.00.0000
6212 \begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
6218 Hides your ugly and inefficient c-code from the asm file, so you can always
6219 blame the compiler :).
6221 \labelwidthstring 00.00.0000
6236 \begin_inset LatexCommand \index{-\/-i-code-in-asm}
6242 Include i-codes in the asm file.
6243 Sounds like noise but is most helpful for debugging the compiler itself.
6245 \labelwidthstring 00.00.0000
6260 \begin_inset LatexCommand \index{-\/-less-pedantic}
6266 Disable some of the more pedantic warnings (jwk burps: please be more specific
6269 \labelwidthstring 00.00.0000
6284 \begin_inset LatexCommand \index{-\/-print-search-dirs}
6290 Display the directories in the compiler's search path
6292 \labelwidthstring 00.00.0000
6307 \begin_inset LatexCommand \index{-\/-print-search-dirs}
6313 Display the errors and warnings using MSVC style, so you can use SDCC with
6315 \layout Subsubsection
6317 Intermediate Dump Options
6318 \begin_inset LatexCommand \index{Options intermediate dump}
6323 \begin_inset LatexCommand \index{Intermediate dump options}
6330 The following options are provided for the purpose of retargetting and debugging
6332 These provided a means to dump the intermediate code (iCode
6333 \begin_inset LatexCommand \index{iCode}
6337 ) generated by the compiler in human readable form at various stages of
6338 the compilation process.
6341 \labelwidthstring 00.00.0000
6356 \begin_inset LatexCommand \index{-\/-dumpraw}
6362 This option will cause the compiler to dump the intermediate code into
6365 <source filename>.dumpraw
6367 just after the intermediate code has been generated for a function, i.e.
6368 before any optimizations are done.
6370 \begin_inset LatexCommand \index{Basic blocks}
6374 at this stage ordered in the depth first number, so they may not be in
6375 sequence of execution.
6377 \labelwidthstring 00.00.0000
6392 \begin_inset LatexCommand \index{-\/-dumpgcse}
6398 Will create a dump of iCode's, after global subexpression elimination
6399 \begin_inset LatexCommand \index{Global subexpression elimination}
6405 <source filename>.dumpgcse.
6407 \labelwidthstring 00.00.0000
6422 \begin_inset LatexCommand \index{-\/-dumpdeadcode}
6428 Will create a dump of iCode's, after deadcode elimination
6429 \begin_inset LatexCommand \index{Dead-code elimination}
6435 <source filename>.dumpdeadcode.
6437 \labelwidthstring 00.00.0000
6452 \begin_inset LatexCommand \index{-\/-dumploop}
6461 Will create a dump of iCode's, after loop optimizations
6462 \begin_inset LatexCommand \index{Loop optimization}
6468 <source filename>.dumploop.
6470 \labelwidthstring 00.00.0000
6485 \begin_inset LatexCommand \index{-\/-dumprange}
6494 Will create a dump of iCode's, after live range analysis
6495 \begin_inset LatexCommand \index{Live range analysis}
6501 <source filename>.dumprange.
6503 \labelwidthstring 00.00.0000
6518 \begin_inset LatexCommand \index{-\/-dumlrange}
6524 Will dump the life ranges
6525 \begin_inset LatexCommand \index{Live range analysis}
6531 \labelwidthstring 00.00.0000
6546 \begin_inset LatexCommand \index{-\/-dumpregassign}
6555 Will create a dump of iCode's, after register assignment
6556 \begin_inset LatexCommand \index{Register assignment}
6562 <source filename>.dumprassgn.
6564 \labelwidthstring 00.00.0000
6579 \begin_inset LatexCommand \index{-\/-dumplrange}
6585 Will create a dump of the live ranges of iTemp's
6587 \labelwidthstring 00.00.0000
6602 \begin_inset LatexCommand \index{-\/-dumpall}
6613 Will cause all the above mentioned dumps to be created.
6616 Environment variables
6617 \begin_inset LatexCommand \index{Environment variables}
6624 SDCC recognizes the following environment variables:
6626 \labelwidthstring 00.00.0000
6631 \begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
6637 SDCC installs a signal handler
6638 \begin_inset LatexCommand \index{signal handler}
6642 to be able to delete temporary files after an user break (^C) or an exception.
6643 If this environment variable is set, SDCC won't install the signal handler
6644 in order to be able to debug SDCC.
6646 \labelwidthstring 00.00.0000
6651 \begin_inset LatexCommand \index{TMP}
6657 \begin_inset LatexCommand \index{TEMP}
6663 \begin_inset LatexCommand \index{TMPDIR}
6669 Path, where temporary files will be created.
6670 The order of the variables is the search order.
6671 In a standard *nix environment these variables are not set, and there's
6672 no need to set them.
6673 On Windows it's recommended to set one of them.
6675 \labelwidthstring 00.00.0000
6680 \begin_inset LatexCommand \index{SDCC\_HOME}
6687 \begin_inset Quotes sld
6690 2.3 Install and search paths
6691 \begin_inset Quotes srd
6696 \labelwidthstring 00.00.0000
6701 \begin_inset LatexCommand \index{SDCC\_INCLUDE}
6708 \begin_inset Quotes sld
6711 2.3 Install and search paths
6712 \begin_inset Quotes srd
6717 \labelwidthstring 00.00.0000
6722 \begin_inset LatexCommand \index{SDCC\_LIB}
6729 \begin_inset Quotes sld
6732 2.3 Install and search paths
6733 \begin_inset Quotes srd
6739 There are some more environment variables recognized by SDCC, but these
6740 are solely used for debugging purposes.
6741 They can change or disappear very quickly, and will never be documented.
6744 MCS51/DS390 Storage Class
6745 \begin_inset LatexCommand \index{Storage class}
6752 In addition to the ANSI storage classes SDCC allows the following MCS51
6753 specific storage classes.
6754 \layout Subsubsection
6757 \begin_inset LatexCommand \index{xdata}
6764 Variables declared with this storage class will be placed in the extern
6770 storage class for Large Memory model, e.g.:
6775 xdata unsigned char xduc;
6776 \layout Subsubsection
6779 \begin_inset LatexCommand \index{data}
6790 storage class for Small Memory model.
6791 Variables declared with this storage class will be allocated in the internal
6798 \layout Subsubsection
6801 \begin_inset LatexCommand \index{idata}
6808 Variables declared with this storage class will be allocated into the indirectly
6809 addressable portion of the internal ram of a 8051, e.g.:
6815 \layout Subsubsection
6818 \begin_inset LatexCommand \index{bit}
6825 This is a data-type and a storage class specifier.
6826 When a variable is declared as a bit, it is allocated into the bit addressable
6827 memory of 8051, e.g.:
6833 \layout Subsubsection
6836 \begin_inset LatexCommand \index{sfr}
6841 \begin_inset LatexCommand \index{sbit}
6848 Like the bit keyword,
6852 signifies both a data-type and storage class, they are used to describe
6853 the special function registers and special bit variables of a 8051, eg:
6858 sfr at 0x80 P0; /* special function register P0 at location 0x80 */
6860 sbit at 0xd7 CY; /* CY (Carry Flag
6861 \begin_inset LatexCommand \index{Flags}
6866 \begin_inset LatexCommand \index{Carry flag}
6874 \begin_inset LatexCommand \index{Pointers}
6881 SDCC allows (via language extensions) pointers to explicitly point to any
6882 of the memory spaces
6883 \begin_inset LatexCommand \index{Memory model}
6888 In addition to the explicit pointers, the compiler uses (by default) generic
6889 pointers which can be used to point to any of the memory spaces.
6893 Pointer declaration examples:
6898 /* pointer physically in xternal ram pointing to object in internal ram
6901 data unsigned char * xdata p;
6905 /* pointer physically in code rom pointing to data in xdata space */
6907 xdata unsigned char * code p;
6911 /* pointer physically in code space pointing to data in code space */
6913 code unsigned char * code p;
6917 /* the following is a generic pointer physically located in xdata space
6923 Well you get the idea.
6928 All unqualified pointers are treated as 3-byte (4-byte for the ds390)
6941 The highest order byte of the
6945 pointers contains the data space information.
6946 Assembler support routines are called whenever data is stored or retrieved
6952 These are useful for developing reusable library
6953 \begin_inset LatexCommand \index{Libraries}
6958 Explicitly specifying the pointer type will generate the most efficient
6963 \begin_inset LatexCommand \index{Parameters}
6968 \begin_inset LatexCommand \index{Local variable}
6975 Automatic (local) variables and parameters to functions can either be placed
6976 on the stack or in data-space.
6977 The default action of the compiler is to place these variables in the internal
6978 RAM (for small model) or external RAM (for large model).
6979 This in fact makes them
6982 \begin_inset LatexCommand \index{static}
6988 so by default functions are non-reentrant
6989 \begin_inset LatexCommand \index{reentrant}
6997 They can be placed on the stack
6998 \begin_inset LatexCommand \index{stack}
7015 \begin_inset LatexCommand \index{-\/-stack-auto}
7021 option or by using the
7024 \begin_inset LatexCommand \index{reentrant}
7030 keyword in the function declaration, e.g.:
7035 unsigned char foo(char i) reentrant
7045 Since stack space on 8051 is limited, the
7063 option should be used sparingly.
7064 Note that the reentrant keyword just means that the parameters & local
7065 variables will be allocated to the stack, it
7069 mean that the function is register bank independent.
7073 Local variables can be assigned storage classes and absolute
7074 \begin_inset LatexCommand \index{Absolute addressing}
7083 unsigned char foo() {
7089 xdata unsigned char i;
7101 data at 0x31 unsigned char j;
7113 In the above example the variable
7117 will be allocated in the external ram,
7121 in bit addressable space and
7140 or when a function is declared as
7144 this should only be done for static variables.
7147 Parameters however are not allowed any storage class, (storage classes for
7148 parameters will be ignored), their allocation is governed by the memory
7149 model in use, and the reentrancy options.
7153 \begin_inset LatexCommand \index{Overlaying}
7161 \begin_inset LatexCommand \index{reentrant}
7165 functions SDCC will try to reduce internal ram space usage by overlaying
7166 parameters and local variables of a function (if possible).
7167 Parameters and local variables of a function will be allocated to an overlayabl
7168 e segment if the function has
7170 no other function calls and the function is non-reentrant and the memory
7172 \begin_inset LatexCommand \index{Memory model}
7179 If an explicit storage class
7180 \begin_inset LatexCommand \index{Storage class}
7184 is specified for a local variable, it will NOT be overlayed.
7187 Note that the compiler (not the linkage editor) makes the decision for overlayin
7189 Functions that are called from an interrupt service routine should be preceded
7190 by a #pragma\SpecialChar ~
7192 \begin_inset LatexCommand \index{\#pragma NOOVERLAY}
7196 if they are not reentrant.
7199 Also note that the compiler does not do any processing of inline
7200 \begin_inset LatexCommand \index{inline}
7204 assembler code, so the compiler might incorrectly assign local variables
7205 and parameters of a function into the overlay segment if the inline assembler
7206 code calls other c-functions that might use the overlay.
7207 In that case the #pragma\SpecialChar ~
7208 NOOVERLAY should be used.
7211 Parameters and Local variables of functions that contain 16 or 32 bit multiplica
7213 \begin_inset LatexCommand \index{Multiplication}
7218 \begin_inset LatexCommand \index{Division}
7222 will NOT be overlayed since these are implemented using external functions,
7231 \begin_inset LatexCommand \index{\#pragma NOOVERLAY}
7237 void set_error(unsigned char errcd)
7253 void some_isr () interrupt
7254 \begin_inset LatexCommand \index{interrupt}
7259 \begin_inset LatexCommand \index{using}
7289 In the above example the parameter
7297 would be assigned to the overlayable segment if the #pragma\SpecialChar ~
7299 not present, this could cause unpredictable runtime behavior when called
7301 The #pragma\SpecialChar ~
7302 NOOVERLAY ensures that the parameters and local variables for
7303 the function are NOT overlayed.
7306 Interrupt Service Routines
7309 SDCC allows interrupt service routines to be coded in C, with some extended
7315 void timer_isr (void) interrupt 2 using 1
7325 The number following the
7328 \begin_inset LatexCommand \index{interrupt}
7334 keyword is the interrupt number this routine will service.
7335 The compiler will insert a call to this routine in the interrupt vector
7336 table for the interrupt number specified.
7341 keyword is used to tell the compiler to use the specified register bank
7342 (8051 specific) when generating code for this function.
7343 Note that when some function is called from an interrupt service routine
7344 it should be preceded by a #pragma\SpecialChar ~
7346 \begin_inset LatexCommand \index{\#pragma NOOVERLAY}
7350 if it is not reentrant.
7351 A special note here, int (16 bit) and long (32 bit) integer division
7352 \begin_inset LatexCommand \index{Division}
7357 \begin_inset LatexCommand \index{Multiplication}
7362 \begin_inset LatexCommand \index{Modulus}
7366 operations are implemented using external support routines developed in
7367 ANSI-C, if an interrupt service routine needs to do any of these operations
7368 then the support routines (as mentioned in a following section) will have
7369 to be recompiled using the
7382 \begin_inset LatexCommand \index{-\/-stack-auto}
7388 option and the source file will need to be compiled using the
7403 \begin_inset LatexCommand \index{-\/-int-long-rent}
7410 If you have multiple source files in your project, interrupt service routines
7411 can be present in any of them, but a prototype of the isr MUST be present
7412 or included in the file that contains the function
7419 Interrupt Numbers and the corresponding address & descriptions for the Standard
7420 8051 are listed below.
7421 SDCC will automatically adjust the interrupt vector table to the maximum
7422 interrupt number specified.
7428 \begin_inset Tabular
7429 <lyxtabular version="3" rows="6" columns="3">
7431 <column alignment="block" valignment="top" leftline="true" width="0in">
7432 <column alignment="block" valignment="top" leftline="true" width="0in">
7433 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
7434 <row topline="true" bottomline="true">
7435 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7443 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7451 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
7460 <row topline="true">
7461 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7469 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7477 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
7486 <row topline="true">
7487 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7495 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7503 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
7512 <row topline="true">
7513 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7521 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7529 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
7538 <row topline="true">
7539 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7547 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7555 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
7564 <row topline="true" bottomline="true">
7565 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7573 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
7581 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
7598 If the interrupt service routine is defined without
7601 \begin_inset LatexCommand \index{using}
7607 a register bank or with register bank 0 (using 0), the compiler will save
7608 the registers used by itself on the stack upon entry and restore them at
7609 exit, however if such an interrupt service routine calls another function
7610 then the entire register bank will be saved on the stack.
7611 This scheme may be advantageous for small interrupt service routines which
7612 have low register usage.
7615 If the interrupt service routine is defined to be using a specific register
7620 are save and restored, if such an interrupt service routine calls another
7621 function (using another register bank) then the entire register bank of
7622 the called function will be saved on the stack.
7623 This scheme is recommended for larger interrupt service routines.
7626 Calling other functions from an interrupt service routine is not recommended,
7627 avoid it if possible.
7631 Also see the _naked modifier.
7639 <TODO: this isn't implemented at all!>
7645 A special keyword may be associated with a function declaring it as
7650 SDCC will generate code to disable all interrupts upon entry to a critical
7651 function and enable them back before returning.
7652 Note that nesting critical functions may cause unpredictable results.
7670 The critical attribute maybe used with other attributes like
7676 \begin_inset LatexCommand \index{Naked functions}
7683 A special keyword may be associated with a function declaring it as
7686 \begin_inset LatexCommand \index{\_naked}
7697 function modifier attribute prevents the compiler from generating prologue
7698 \begin_inset LatexCommand \index{function prologue}
7703 \begin_inset LatexCommand \index{function epilogue}
7707 code for that function.
7708 This means that the user is entirely responsible for such things as saving
7709 any registers that may need to be preserved, selecting the proper register
7710 bank, generating the
7714 instruction at the end, etc.
7715 Practically, this means that the contents of the function must be written
7716 in inline assembler.
7717 This is particularly useful for interrupt functions, which can have a large
7718 (and often unnecessary) prologue/epilogue.
7719 For example, compare the code generated by these two functions:
7724 data unsigned char counter;
7726 void simpleInterrupt(void) interrupt
7727 \begin_inset LatexCommand \index{interrupt}
7745 void nakedInterrupt(void) interrupt 2 _naked
7754 \begin_inset LatexCommand \index{\_asm}
7783 ; MUST explicitly include ret in _naked function.
7790 \begin_inset LatexCommand \index{\_endasm}
7799 For an 8051 target, the generated simpleInterrupt looks like:
7940 whereas nakedInterrupt looks like:
7964 ; MUST explicitly include ret(i) in _naked function.
7967 While there is nothing preventing you from writing C code inside a _naked
7968 function, there are many ways to shoot yourself in the foot doing this,
7969 and it is recommended that you stick to inline assembler.
7972 Functions using private banks
7973 \begin_inset LatexCommand \index{bank}
7983 \begin_inset LatexCommand \index{using}
7989 attribute (which tells the compiler to use a register bank other than the
7990 default bank zero) should only be applied to
7993 \begin_inset LatexCommand \index{interrupt}
7999 functions (see note 1 below).
8000 This will in most circumstances make the generated ISR code more efficient
8001 since it will not have to save registers on the stack.
8008 attribute will have no effect on the generated code for a
8012 function (but may occasionally be useful anyway
8018 possible exception: if a function is called ONLY from 'interrupt' functions
8019 using a particular bank, it can be declared with the same 'using' attribute
8020 as the calling 'interrupt' functions.
8021 For instance, if you have several ISRs using bank one, and all of them
8022 call memcpy(), it might make sense to create a specialized version of memcpy()
8023 'using 1', since this would prevent the ISR from having to save bank zero
8024 to the stack on entry and switch to bank zero before calling the function
8031 (pending: I don't think this has been done yet)
8038 function using a non-zero bank will assume that it can trash that register
8039 bank, and will not save it.
8040 Since high-priority interrupts
8041 \begin_inset LatexCommand \index{interrupt priority}
8045 can interrupt low-priority ones on the 8051 and friends, this means that
8046 if a high-priority ISR
8050 a particular bank occurs while processing a low-priority ISR
8054 the same bank, terrible and bad things can happen.
8055 To prevent this, no single register bank should be
8059 by both a high priority and a low priority ISR.
8060 This is probably most easily done by having all high priority ISRs use
8061 one bank and all low priority ISRs use another.
8062 If you have an ISR which can change priority at runtime, you're on your
8063 own: I suggest using the default bank zero and taking the small performance
8067 It is most efficient if your ISR calls no other functions.
8068 If your ISR must call other functions, it is most efficient if those functions
8069 use the same bank as the ISR (see note 1 below); the next best is if the
8070 called functions use bank zero.
8071 It is very inefficient to call a function using a different, non-zero bank
8077 \begin_inset LatexCommand \index{Absolute addressing}
8084 Data items can be assigned an absolute address with the
8087 \begin_inset LatexCommand \index{at}
8093 keyword, in addition to a storage class, e.g.:
8099 \begin_inset LatexCommand \index{xdata}
8104 \begin_inset LatexCommand \index{at}
8108 0x8000 unsigned char PORTA_8255 ;
8111 In the above example the PORTA_8255 will be allocated to the location 0x8000
8112 of the external ram.
8113 Note that this feature is provided to give the programmer access to
8117 devices attached to the controller.
8118 The compiler does not actually reserve any space for variables declared
8119 in this way (they are implemented with an equate in the assembler).
8120 Thus it is left to the programmer to make sure there are no overlaps with
8121 other variables that are declared without the absolute address.
8122 The assembler listing file (.lst
8123 \begin_inset LatexCommand \index{.lst}
8127 ) and the linker output files (.rst
8128 \begin_inset LatexCommand \index{.rst}
8133 \begin_inset LatexCommand \index{.map}
8137 ) are a good places to look for such overlaps.
8141 Absolute address can be specified for variables in all storage classes,
8148 \begin_inset LatexCommand \index{bit}
8153 \begin_inset LatexCommand \index{at}
8160 The above example will allocate the variable at offset 0x02 in the bit-addressab
8162 There is no real advantage to assigning absolute addresses to variables
8163 in this manner, unless you want strict control over all the variables allocated.
8164 One possible use would be to write hardware portable code.
8165 For example, if you have a routine that uses one or more of the microcontroller
8166 I/O pins, and such pins are different for two different hardwares, you
8167 can declare the I/O pins in you routine using
8180 void DS1306_put(unsigned char value)
8188 unsigned char mask=0x80;
8212 SDI=(value & mask)?1:0;
8253 Then, someplace in the code for the first hardware you would use
8258 bit at 0x80 SDI;\SpecialChar ~
8262 /*I/O port 0, bit 0*/
8264 bit at 0x81 SCLK;\SpecialChar ~
8267 /*I/O port 0, bit 1*/
8269 bit CPOL;\SpecialChar ~
8280 /*This is a variable, let the linker allocate this one*/
8283 Similarly, for the second hardware you would use
8288 bit at 0x83 SDI;\SpecialChar ~
8292 /*I/O port 0, bit 3*/
8294 bit at 0x91 SCLK;\SpecialChar ~
8297 /*I/O port 1, bit 1*/
8299 bit CPOL;\SpecialChar ~
8310 /*This is a variable, let the linker allocate this one*/
8313 and you can use the same hardware dependent routine without changes, as
8314 for example in a library.
8315 This is somehow similar to sbit, but only one absolute address has to be
8316 specified in the whole project.
8320 \begin_inset LatexCommand \index{Startup code}
8327 The compiler inserts a call to the C routine
8329 _sdcc_external_startup()
8330 \begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
8339 at the start of the CODE area.
8340 This routine is in the runtime library
8341 \begin_inset LatexCommand \index{Runtime library}
8346 By default this routine returns 0, if this routine returns a non-zero value,
8347 the static & global variable initialization will be skipped and the function
8348 main will be invoked Other wise static & global variables will be initialized
8349 before the function main is invoked.
8352 _sdcc_external_startup()
8354 routine to your program to override the default if you need to setup hardware
8355 or perform some other critical operation prior to static & global variable
8359 Inline Assembler Code
8360 \begin_inset LatexCommand \index{Assembler routines}
8367 SDCC allows the use of in-line assembler with a few restriction as regards
8369 All labels defined within inline assembler code
8377 where nnnn is a number less than 100 (which implies a limit of utmost 100
8378 inline assembler labels
8386 It is strongly recommended that each assembly instruction (including labels)
8387 be placed in a separate line (as the example shows).
8401 \begin_inset LatexCommand \index{-\/-peep-asm}
8407 command line option is used, the inline assembler code will be passed through
8408 the peephole optimizer
8409 \begin_inset LatexCommand \index{Peephole optimizer}
8414 This might cause some unexpected changes in the inline assembler code.
8415 Please go through the peephole optimizer rules defined in file
8419 carefully before using this option.
8425 \begin_inset LatexCommand \index{\_asm}
8455 \begin_inset LatexCommand \index{\_endasm}
8462 The inline assembler code can contain any valid code understood by the assembler
8463 , this includes any assembler directives and comment lines.
8464 The compiler does not do any validation of the code within the
8474 Inline assembler code cannot reference any C-Labels, however it can reference
8476 \begin_inset LatexCommand \index{Labels}
8480 defined by the inline assembler, e.g.:
8505 ; some assembler code
8525 /* some more c code */
8527 clabel:\SpecialChar ~
8529 /* inline assembler cannot reference this label */
8541 $0003: ;label (can be reference by inline assembler only)
8553 /* some more c code */
8558 In other words inline assembly code can access labels defined in inline
8559 assembly within the scope of the function.
8560 The same goes the other way, ie.
8561 labels defines in inline assembly CANNOT be accessed by C statements.
8565 \begin_inset LatexCommand \index{int (16 bit)}
8570 \begin_inset LatexCommand \index{long (32 bit)}
8577 For signed & unsigned int (16 bit) and long (32 bit) variables, division,
8578 multiplication and modulus operations are implemented by support routines.
8579 These support routines are all developed in ANSI-C to facilitate porting
8580 to other MCUs, although some model specific assembler optimizations are
8582 The following files contain the described routine, all of them can be found
8583 in <installdir>/share/sdcc/lib.
8588 \begin_inset Tabular
8589 <lyxtabular version="3" rows="11" columns="2">
8591 <column alignment="center" valignment="top" leftline="true" width="0(null)">
8592 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0(null)">
8593 <row topline="true" bottomline="true">
8594 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8604 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8615 <row topline="true">
8616 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8624 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8629 16 bit multiplication
8633 <row topline="true">
8634 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8642 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8647 signed 16 bit division (calls _divuint)
8651 <row topline="true">
8652 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8660 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8665 unsigned 16 bit division
8669 <row topline="true">
8670 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8678 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8683 signed 16 bit modulus (calls _moduint)
8687 <row topline="true">
8688 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8696 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8701 unsigned 16 bit modulus
8705 <row topline="true">
8706 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8714 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8719 32 bit multiplication
8723 <row topline="true">
8724 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8732 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8737 signed 32 division (calls _divulong)
8741 <row topline="true">
8742 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8750 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8755 unsigned 32 division
8759 <row topline="true">
8760 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8768 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8773 signed 32 bit modulus (calls _modulong)
8777 <row topline="true" bottomline="true">
8778 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8786 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8791 unsigned 32 bit modulus
8807 Since they are compiled as
8812 \begin_inset LatexCommand \index{reentrant}
8817 \begin_inset LatexCommand \index{interrupt}
8821 service routines should not do any of the above operations.
8822 If this is unavoidable then the above routines will need to be compiled
8836 \begin_inset LatexCommand \index{-\/-stack-auto}
8842 option, after which the source program will have to be compiled with
8855 \begin_inset LatexCommand \index{-\/-int-long-rent}
8862 Notice that you don't have to call this routines directly.
8863 The compiler will use them automatically every time a integer operation
8867 Floating Point Support
8868 \begin_inset LatexCommand \index{Floating point support}
8875 SDCC supports IEEE (single precision 4 bytes) floating point numbers.The
8876 floating point support routines are derived from gcc's floatlib.c and consists
8877 of the following routines:
8884 \begin_inset Tabular
8885 <lyxtabular version="3" rows="17" columns="2">
8887 <column alignment="center" valignment="top" leftline="true" width="0(null)">
8888 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0(null)">
8889 <row topline="true" bottomline="true">
8890 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8907 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8916 <row topline="true">
8917 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8934 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8948 add floating point numbers
8952 <row topline="true">
8953 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
8970 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
8984 subtract floating point numbers
8988 <row topline="true">
8989 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9006 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9020 divide floating point numbers
9024 <row topline="true">
9025 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9042 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9056 multiply floating point numbers
9060 <row topline="true">
9061 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9078 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9092 convert floating point to unsigned char
9096 <row topline="true">
9097 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9114 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9128 convert floating point to signed char
9132 <row topline="true">
9133 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9150 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9164 convert floating point to unsigned int
9168 <row topline="true">
9169 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9186 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9200 convert floating point to signed int
9204 <row topline="true">
9205 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9231 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9245 convert floating point to unsigned long
9249 <row topline="true">
9250 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9267 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9281 convert floating point to signed long
9285 <row topline="true">
9286 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9303 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9317 convert unsigned char to floating point
9321 <row topline="true">
9322 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9339 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9353 convert char to floating point number
9357 <row topline="true">
9358 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9375 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9389 convert unsigned int to floating point
9393 <row topline="true">
9394 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9411 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9425 convert int to floating point numbers
9429 <row topline="true">
9430 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9447 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9461 convert unsigned long to floating point number
9465 <row topline="true" bottomline="true">
9466 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
9483 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
9497 convert long to floating point number
9511 Note if all these routines are used simultaneously the data space might
9513 For serious floating point usage it is strongly recommended that the large
9515 Also notice that you don't have to call this routines directly.
9516 The compiler will use them automatically every time a floating point operation
9521 \begin_inset LatexCommand \index{Memory model}
9526 \begin_inset LatexCommand \index{MCS51 memory}
9533 SDCC allows two memory models for MCS51 code, small and large.
9534 Modules compiled with different memory models should
9538 be combined together or the results would be unpredictable.
9539 The library routines supplied with the compiler are compiled as both small
9541 The compiled library modules are contained in separate directories as small
9542 and large so that you can link to either set.
9546 When the large model is used all variables declared without a storage class
9547 will be allocated into the external ram, this includes all parameters and
9548 local variables (for non-reentrant
9549 \begin_inset LatexCommand \index{reentrant}
9554 When the small model is used variables without storage class are allocated
9555 in the internal ram.
9558 Judicious usage of the processor specific storage classes
9559 \begin_inset LatexCommand \index{Storage class}
9563 and the 'reentrant' function type will yield much more efficient code,
9564 than using the large model.
9565 Several optimizations are disabled when the program is compiled using the
9566 large model, it is therefore strongly recommended that the small model
9567 be used unless absolutely required.
9571 \begin_inset LatexCommand \index{Memory model}
9576 \begin_inset LatexCommand \index{DS390 memory model}
9583 The only model supported is Flat 24
9584 \begin_inset LatexCommand \index{Flat 24 (memory model)}
9589 This generates code for the 24 bit contiguous addressing mode of the Dallas
9591 In this mode, up to four meg of external RAM or code space can be directly
9593 See the data sheets at www.dalsemi.com for further information on this part.
9597 In older versions of the compiler, this option was used with the MCS51 code
9603 Now, however, the '390 has it's own code generator, selected by the
9612 Note that the compiler does not generate any code to place the processor
9613 into 24 bitmode (although
9617 in the ds390 libraries will do that for you).
9623 \begin_inset LatexCommand \index{Tinibios (DS390)}
9627 , the boot loader or similar code must ensure that the processor is in 24
9628 bit contiguous addressing mode before calling the SDCC startup code.
9646 option, variables will by default be placed into the XDATA segment.
9651 Segments may be placed anywhere in the 4 meg address space using the usual
9663 Note that if any segments are located above 64K, the -r flag must be passed
9664 to the linker to generate the proper segment relocations, and the Intel
9665 HEX output format must be used.
9666 The -r flag can be passed to the linker by using the option
9670 on the sdcc command line.
9671 However, currently the linker can not handle code segments > 64k.
9674 Defines Created by the Compiler
9675 \begin_inset LatexCommand \index{Defines created by the compiler}
9682 The compiler creates the following #defines
9683 \begin_inset LatexCommand \index{\#defines}
9691 \begin_inset LatexCommand \index{SDCC}
9695 - this Symbol is always defined.
9699 \begin_inset LatexCommand \index{SDCC\_mcs51}
9704 \begin_inset LatexCommand \index{SDCC\_ds390}
9709 \begin_inset LatexCommand \index{SDCC\_z80}
9713 , etc - depending on the model used (e.g.: -mds390)
9717 \begin_inset LatexCommand \index{\_\_mcs51}
9722 \begin_inset LatexCommand \index{\_\_ds390}
9727 \begin_inset LatexCommand \index{\_\_z80}
9731 , etc - depending on the model used (e.g.
9736 \begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}
9740 - this symbol is defined when
9758 \begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
9780 \begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
9802 \begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
9824 \begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
9836 \begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
9847 Redirecting output on Windows Shells
9850 SDCC writes it's error messages to
9851 \begin_inset Quotes sld
9855 \begin_inset Quotes srd
9859 The windows 95/98/me shell (command or cmd) can't redirect it to a file.
9860 The solution is to use a reasonable shell or a helper program like redir.exe:
9864 \begin_inset LatexCommand \url{http://www.cygwin.com/ml/cygwin/1999-02/msg00603.html}
9872 \begin_inset LatexCommand \url{ftp://ftp.xraylith.wisc.edu/pub/khan/gnu-win32/mingw32/misc/redir.zip}
9880 \begin_inset LatexCommand \url{ftp://ftp.xraylith.wisc.edu/pub/khan/gnu-win32/mingw32/misc/README.redir}
9888 If you are using a windows NT/2K/XP shell, you can redirect the
9889 \begin_inset Quotes sld
9893 \begin_inset Quotes srd
9896 output to a file using
9897 \begin_inset Quotes sld
9901 \begin_inset Quotes srd
9911 sdcc -c foo.c 2> foo.err
9918 \begin_inset Quotes sld
9922 \begin_inset Quotes srd
9925 output of SDCC to a file you can use
9926 \begin_inset Quotes sld
9930 \begin_inset Quotes srd
9934 I you happen to have visual studio installed in your windows machine, you
9935 can use it to compile your sources using a custom build and the SDCC -
9950 Something like this should work:
9994 -model-large -c $(InputPath)
10001 \begin_inset LatexCommand \index{Optimizations}
10008 SDCC performs a host of standard optimizations in addition to some MCU specific
10011 \layout Subsubsection
10013 Sub-expression Elimination
10014 \begin_inset LatexCommand \index{Subexpression elimination}
10021 The compiler does local and global common subexpression elimination, e.g.:
10032 will be translated to
10044 Some subexpressions are not as obvious as the above example, e.g.:
10054 In this case the address arithmetic a->b[i] will be computed only once;
10055 the equivalent code in C would be.
10067 The compiler will try to keep these temporary variables in registers.
10068 \layout Subsubsection
10070 Dead-Code Elimination
10071 \begin_inset LatexCommand \index{Dead-code elimination}
10090 i = 1; \SpecialChar ~
10095 global = 1;\SpecialChar ~
10108 global = 3;\SpecialChar ~
10119 int global; void f ()
10132 \layout Subsubsection
10135 \begin_inset LatexCommand \index{Copy propagation}
10191 Note: the dead stores created by this copy propagation will be eliminated
10192 by dead-code elimination.
10193 \layout Subsubsection
10196 \begin_inset LatexCommand \index{Loop optimization}
10203 Two types of loop optimizations are done by SDCC loop invariant lifting
10204 and strength reduction of loop induction variables.
10205 In addition to the strength reduction the optimizer marks the induction
10206 variables and the register allocator tries to keep the induction variables
10207 in registers for the duration of the loop.
10208 Because of this preference of the register allocator
10209 \begin_inset LatexCommand \index{Register allocation}
10213 , loop induction optimization causes an increase in register pressure, which
10214 may cause unwanted spilling of other temporary variables into the stack
10215 \begin_inset LatexCommand \index{stack}
10220 The compiler will generate a warning message when it is forced to allocate
10221 extra space either on the stack or data space.
10222 If this extra space allocation is undesirable then induction optimization
10223 can be eliminated either for the entire source file (with -
10233 -noinduction option) or for a given function only using #pragma\SpecialChar ~
10235 \begin_inset LatexCommand \index{\#pragma NOINDUCTION}
10248 for (i = 0 ; i < 100 ; i ++)
10262 for (i = 0; i < 100; i++)
10269 As mentioned previously some loop invariants are not as apparent, all static
10270 address computations are also moved out of the loop.
10275 \begin_inset LatexCommand \index{Strength reduction}
10279 , this optimization substitutes an expression by a cheaper expression:
10284 for (i=0;i < 100; i++)
10300 for (i=0;i< 100;i++) {
10304 ar[itemp1] = itemp2;
10317 The more expensive multiplication
10318 \begin_inset LatexCommand \index{Multiplication}
10322 is changed to a less expensive addition.
10323 \layout Subsubsection
10326 \begin_inset LatexCommand \index{Loop reversing}
10333 This optimization is done to reduce the overhead of checking loop boundaries
10334 for every iteration.
10335 Some simple loops can be reversed and implemented using a
10336 \begin_inset Quotes eld
10339 decrement and jump if not zero
10340 \begin_inset Quotes erd
10344 SDCC checks for the following criterion to determine if a loop is reversible
10345 (note: more sophisticated compilers use data-dependency analysis to make
10346 this determination, SDCC uses a more simple minded analysis).
10349 The 'for' loop is of the form
10355 for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
10365 The <for body> does not contain
10366 \begin_inset Quotes eld
10370 \begin_inset Quotes erd
10374 \begin_inset Quotes erd
10380 All goto's are contained within the loop.
10383 No function calls within the loop.
10386 The loop control variable <sym> is not assigned any value within the loop
10389 The loop control variable does NOT participate in any arithmetic operation
10393 There are NO switch statements in the loop.
10394 \layout Subsubsection
10396 Algebraic Simplifications
10399 SDCC does numerous algebraic simplifications, the following is a small sub-set
10400 of these optimizations.
10405 i = j + 0 ; /* changed to */ i = j;
10407 i /= 2; /* changed to */ i >>= 1;
10409 i = j - j ; /* changed to */ i = 0;
10411 i = j / 1 ; /* changed to */ i = j;
10414 Note the subexpressions
10415 \begin_inset LatexCommand \index{Subexpression}
10419 given above are generally introduced by macro expansions or as a result
10420 of copy/constant propagation.
10421 \layout Subsubsection
10423 'switch' Statements
10424 \begin_inset LatexCommand \index{switch statement}
10431 SDCC changes switch statements to jump tables
10432 \begin_inset LatexCommand \index{jump tables}
10436 when the following conditions are true.
10440 The case labels are in numerical sequence, the labels need not be in order,
10441 and the starting number need not be one or zero.
10447 switch(i) {\SpecialChar ~
10551 Both the above switch statements will be implemented using a jump-table.
10555 The number of case labels is at least three, since it takes two conditional
10556 statements to handle the boundary conditions.
10559 The number of case labels is less than 84, since each label takes 3 bytes
10560 and a jump-table can be utmost 256 bytes long.
10564 Switch statements which have gaps in the numeric sequence or those that
10565 have more that 84 case labels can be split into more than one switch statement
10566 for efficient code generation, e.g.:
10616 If the above switch statement is broken down into two switch statements
10655 case 9: \SpecialChar ~
10671 case 12:\SpecialChar ~
10678 then both the switch statements will be implemented using jump-tables whereas
10679 the unmodified switch statement will not be.
10680 \layout Subsubsection
10682 Bit-shifting Operations
10683 \begin_inset LatexCommand \index{Bit shifting}
10690 Bit shifting is one of the most frequently used operation in embedded programmin
10692 SDCC tries to implement bit-shift operations in the most efficient way
10708 generates the following code:
10722 In general SDCC will never setup a loop if the shift count is known.
10754 Note that SDCC stores numbers in little-endian format (i.e.
10755 lowest order first).
10756 \layout Subsubsection
10759 \begin_inset LatexCommand \index{Bit rotation}
10766 A special case of the bit-shift operation is bit rotation, SDCC recognizes
10767 the following expression to be a left bit-rotation:
10777 i = ((i << 1) | (i >> 7));
10786 will generate the following code:
10798 SDCC uses pattern matching on the parse tree to determine this operation.Variatio
10799 ns of this case will also be recognized as bit-rotation, i.e.:
10804 i = ((i >> 7) | (i << 1)); /* left-bit rotation */
10805 \layout Subsubsection
10808 \begin_inset LatexCommand \index{Highest Order Bit}
10815 It is frequently required to obtain the highest order bit of an integral
10816 type (long, int, short or char types).
10817 SDCC recognizes the following expression to yield the highest order bit
10818 and generates optimized code for it, e.g.:
10838 hob = (gint >> 15) & 1;
10848 will generate the following code:
10881 000A E5*01\SpecialChar ~
10907 000C 33\SpecialChar ~
10936 000D E4\SpecialChar ~
10965 000E 13\SpecialChar ~
10994 000F F5*02\SpecialChar ~
11021 Variations of this case however will
11026 It is a standard C expression, so I heartily recommend this be the only
11027 way to get the highest order bit, (it is portable).
11028 Of course it will be recognized even if it is embedded in other expressions,
11034 xyz = gint + ((gint >> 15) & 1);
11037 will still be recognized.
11038 \layout Subsubsection
11041 \begin_inset LatexCommand \index{Peephole optimizer}
11048 The compiler uses a rule based, pattern matching and re-writing mechanism
11049 for peep-hole optimization.
11054 a peep-hole optimizer by Christopher W.
11055 Fraser (cwfraser@microsoft.com).
11056 A default set of rules are compiled into the compiler, additional rules
11057 may be added with the
11070 \begin_inset LatexCommand \index{-\/-peep-file}
11077 The rule language is best illustrated with examples.
11101 The above rule will change the following assembly
11102 \begin_inset LatexCommand \index{Assembler routines}
11124 Note: All occurrences of a
11128 (pattern variable) must denote the same string.
11129 With the above rule, the assembly sequence:
11139 will remain unmodified.
11143 Other special case optimizations may be added by the user (via
11159 some variants of the 8051 MCU allow only
11168 The following two rules will change all
11187 replace { lcall %1 } by { acall %1 }
11189 replace { ljmp %1 } by { ajmp %1 }
11194 inline-assembler code
11196 is also passed through the peep hole optimizer, thus the peephole optimizer
11197 can also be used as an assembly level macro expander.
11198 The rules themselves are MCU dependent whereas the rule language infra-structur
11199 e is MCU independent.
11200 Peephole optimization rules for other MCU can be easily programmed using
11205 The syntax for a rule is as follows:
11210 rule := replace [ restart ] '{' <assembly sequence> '
11248 <assembly sequence> '
11266 '}' [if <functionName> ] '
11271 <assembly sequence> := assembly instruction (each instruction including
11272 labels must be on a separate line).
11276 The optimizer will apply to the rules one by one from the top in the sequence
11277 of their appearance, it will terminate when all rules are exhausted.
11278 If the 'restart' option is specified, then the optimizer will start matching
11279 the rules again from the top, this option for a rule is expensive (performance)
11280 , it is intended to be used in situations where a transformation will trigger
11281 the same rule again.
11282 An example of this (not a good one, it has side effects) is the following
11305 Note that the replace pattern cannot be a blank, but can be a comment line.
11306 Without the 'restart' option only the inner most 'pop' 'push' pair would
11307 be eliminated, i.e.:
11337 the restart option the rule will be applied again to the resulting code
11338 and then all the pop-push pairs will be eliminated to yield:
11348 A conditional function can be attached to a rule.
11349 Attaching rules are somewhat more involved, let me illustrate this with
11376 The optimizer does a look-up of a function name table defined in function
11381 in the source file SDCCpeeph.c, with the name
11386 If it finds a corresponding entry the function is called.
11387 Note there can be no parameters specified for these functions, in this
11392 is crucial, since the function
11396 expects to find the label in that particular variable (the hash table containin
11397 g the variable bindings is passed as a parameter).
11398 If you want to code more such functions, take a close look at the function
11399 labelInRange and the calling mechanism in source file SDCCpeeph.c.
11400 I know this whole thing is a little kludgey, but maybe some day we will
11401 have some better means.
11402 If you are looking at this file, you will also see the default rules that
11403 are compiled into the compiler, you can add your own rules in the default
11404 set there if you get tired of specifying the -
11418 \begin_inset LatexCommand \index{Pragmas}
11425 SDCC supports the following #pragma directives.
11429 \begin_inset LatexCommand \index{\#pragma SAVE}
11433 - this will save all current options to the SAVE/RESTORE stack.
11438 \begin_inset LatexCommand \index{\#pragma RESTORE}
11442 - will restore saved options from the last save.
11443 SAVEs & RESTOREs can be nested.
11444 SDCC uses a SAVE/RESTORE stack: SAVE pushes current options to the stack,
11445 RESTORE pulls current options from the stack.
11450 \begin_inset LatexCommand \index{\#pragma NOGCSE}
11454 - will stop global subexpression elimination.
11458 \begin_inset LatexCommand \index{\#pragma NOINDUCTION}
11462 - will stop loop induction optimizations.
11466 \begin_inset LatexCommand \index{\#pragma NOJTBOUND}
11470 - will not generate code for boundary value checking, when switch statements
11471 are turned into jump-tables.
11475 \begin_inset LatexCommand \index{\#pragma NOOVERLAY}
11479 - the compiler will not overlay the parameters and local variables of a
11484 \begin_inset LatexCommand \index{\#pragma LESS\_PEDANTIC}
11488 - the compiler will not warn you anymore for obvious mistakes, you'r on
11493 \begin_inset LatexCommand \index{\#pragma NOLOOPREVERSE}
11497 - Will not do loop reversal optimization
11501 \begin_inset LatexCommand \index{\#pragma EXCLUDE}
11505 NONE | {acc[,b[,dpl[,dph]]] - The exclude pragma disables generation of
11507 \begin_inset LatexCommand \index{push/pop}
11511 instruction in ISR function (using interrupt
11512 \begin_inset LatexCommand \index{interrupt}
11517 The directive should be placed immediately before the ISR function definition
11518 and it affects ALL ISR functions following it.
11519 To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
11520 EXCLUDE\SpecialChar ~
11522 \begin_inset LatexCommand \index{\#pragma EXCLUDE}
11530 \begin_inset LatexCommand \index{\#pragma NOIV}
11534 - Do not generate interrupt vector table entries for all ISR functions
11535 defined after the pragma.
11536 This is useful in cases where the interrupt vector table must be defined
11537 manually, or when there is a secondary, manually defined interrupt vector
11539 for the autovector feature of the Cypress EZ-USB FX2).
11543 \begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
11548 \begin_inset LatexCommand \index{function prologue}
11552 function1[,function2[,function3...]] - The compiler by default uses a caller
11553 saves convention for register saving across function calls, however this
11554 can cause unnecessary register pushing & popping when calling small functions
11555 from larger functions.
11556 This option can be used to switch off the register saving convention for
11557 the function names specified.
11558 The compiler will not save registers when calling these functions, extra
11559 code need to be manually inserted at the entry & exit for these functions
11560 to save & restore the registers used by these functions, this can SUBSTANTIALLY
11561 reduce code & improve run time performance of the generated code.
11562 In the future the compiler (with inter procedural analysis) may be able
11563 to determine the appropriate scheme to use for each function call.
11574 -callee-saves command line option is used, the function names specified
11575 in #pragma\SpecialChar ~
11577 \begin_inset LatexCommand \index{\#pragma CALLEE-SAVES}
11581 is appended to the list of functions specified in the command line.
11584 The pragma's are intended to be used to turn-off certain optimizations which
11585 might cause the compiler to generate extra stack / data space to store
11586 compiler generated temporary variables.
11587 This usually happens in large functions.
11588 Pragma directives should be used as shown in the following example, they
11589 are used to control options & optimizations for a given function; pragmas
11590 should be placed before and/or after a function, placing pragma's inside
11591 a function body could have unpredictable results.
11597 \begin_inset LatexCommand \index{\#pragma SAVE}
11601 /* save the current settings */
11604 \begin_inset LatexCommand \index{\#pragma NOGCSE}
11608 /* turnoff global subexpression elimination */
11610 #pragma NOINDUCTION
11611 \begin_inset LatexCommand \index{\#pragma NOINDUCTION}
11615 /* turn off induction optimizations */
11638 \begin_inset LatexCommand \index{\#pragma RESTORE}
11642 /* turn the optimizations back on */
11645 The compiler will generate a warning message when extra space is allocated.
11646 It is strongly recommended that the SAVE and RESTORE pragma's be used when
11647 changing options for a function.
11652 <pending: this is messy and incomplete>
11657 Compiler support routines (_gptrget, _mulint etc)
11660 Stdclib functions (puts, printf, strcat etc)
11663 Math functions (sin, pow, sqrt etc)
11666 license statements for the libraries are missing
11669 Interfacing with Assembly Routines
11670 \begin_inset LatexCommand \index{Assembler routines}
11675 \layout Subsubsection
11677 Global Registers used for Parameter Passing
11678 \begin_inset LatexCommand \index{Parameter passing}
11685 The compiler always uses the global registers
11688 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
11693 \begin_inset LatexCommand \index{B (register)}
11702 \begin_inset LatexCommand \index{ACC}
11708 to pass the first parameter to a routine.
11709 The second parameter onwards is either allocated on the stack (for reentrant
11720 -stack-auto is used) or in the internal / external ram (depending on the
11723 \layout Subsubsection
11725 Assembler Routine(non-reentrant
11726 \begin_inset LatexCommand \index{reentrant}
11731 \begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
11738 In the following example the function c_func calls an assembler routine
11739 asm_func, which takes two parameters.
11744 extern int asm_func(unsigned char, unsigned char);
11748 int c_func (unsigned char i, unsigned char j)
11756 return asm_func(i,j);
11770 return c_func(10,9);
11775 The corresponding assembler function is:
11780 .globl _asm_func_PARM_2
11844 add a,_asm_func_PARM_2
11869 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
11886 Note here that the return values are placed in 'dpl' - One byte return value,
11887 'dpl' LSB & 'dph' MSB for two byte values.
11888 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
11889 b' & 'acc' for four byte values.
11892 The parameter naming convention is _<function_name>_PARM_<n>, where n is
11893 the parameter number starting from 1, and counting from the left.
11894 The first parameter is passed in
11895 \begin_inset Quotes eld
11899 \begin_inset Quotes erd
11902 for One bye parameter,
11903 \begin_inset Quotes eld
11907 \begin_inset Quotes erd
11911 \begin_inset Quotes eld
11915 \begin_inset Quotes erd
11918 for three bytes and
11919 \begin_inset Quotes eld
11923 \begin_inset Quotes erd
11926 for four bytes, the variable name for the second parameter will be _<function_n
11931 Assemble the assembler routine with the following command:
11938 asx8051 -losg asmfunc.asm
11945 Then compile and link the assembler routine to the C source file with the
11953 sdcc cfunc.c asmfunc.rel
11954 \layout Subsubsection
11956 Assembler Routine(reentrant
11957 \begin_inset LatexCommand \index{reentrant}
11962 \begin_inset LatexCommand \index{Assembler routines (reentrant)}
11969 In this case the second parameter onwards will be passed on the stack, the
11970 parameters are pushed from right to left i.e.
11971 after the call the left most parameter will be on the top of the stack.
11972 Here is an example:
11977 extern int asm_func(unsigned char, unsigned char);
11981 int c_func (unsigned char i, unsigned char j) reentrant
11989 return asm_func(i,j);
12003 return c_func(10,9);
12008 The corresponding assembler routine is:
12114 The compiling and linking procedure remains the same, however note the extra
12115 entry & exit linkage required for the assembler code, _bp is the stack
12116 frame pointer and is used to compute the offset into the stack for parameters
12117 and local variables.
12121 \begin_inset LatexCommand \index{stack}
12126 \begin_inset LatexCommand \index{External stack}
12133 The external stack is located at the start of the external ram segment,
12134 and is 256 bytes in size.
12145 -xstack option is used to compile the program, the parameters and local
12146 variables of all reentrant functions are allocated in this area.
12147 This option is provided for programs with large stack space requirements.
12148 When used with the -
12158 -stack-auto option, all parameters and local variables are allocated on
12159 the external stack (note support libraries will need to be recompiled with
12163 The compiler outputs the higher order address byte of the external ram segment
12164 into PORT P2, therefore when using the External Stack option, this port
12165 MAY NOT be used by the application program.
12169 \begin_inset LatexCommand \index{ANSI-compliance}
12176 Deviations from the compliance:
12179 functions are not always reentrant.
12182 structures cannot be assigned values directly, cannot be passed as function
12183 parameters or assigned to each other and cannot be a return value from
12210 s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
12221 struct s foo1 (struct s parms) /* invalid in SDCC although allowed in ANSI
12243 return rets;/* is invalid in SDCC although allowed in ANSI */
12250 \begin_inset LatexCommand \index{long long (not supported)}
12255 \begin_inset LatexCommand \index{int (64 bit) (not supported)}
12263 \begin_inset LatexCommand \index{double (not supported)}
12267 ' precision floating point
12268 \begin_inset LatexCommand \index{Floating point support}
12275 No support for setjmp and longjmp (for now).
12279 \begin_inset LatexCommand \index{K\&R style}
12283 function declarations are NOT allowed.
12289 foo(i,j) /* this old style of function declarations */
12291 int i,j; /* are valid in ANSI but not valid in SDCC */
12306 functions declared as pointers must be dereferenced during the call.
12317 /* has to be called like this */
12319 (*foo)(); /* ANSI standard allows calls to be made like 'foo()' */
12323 Cyclomatic Complexity
12324 \begin_inset LatexCommand \index{Cyclomatic complexity}
12331 Cyclomatic complexity of a function is defined as the number of independent
12332 paths the program can take during execution of the function.
12333 This is an important number since it defines the number test cases you
12334 have to generate to validate the function.
12335 The accepted industry standard for complexity number is 10, if the cyclomatic
12336 complexity reported by SDCC exceeds 10 you should think about simplification
12337 of the function logic.
12338 Note that the complexity level is not related to the number of lines of
12339 code in a function.
12340 Large functions can have low complexity, and small functions can have large
12346 SDCC uses the following formula to compute the complexity:
12351 complexity = (number of edges in control flow graph) - (number of nodes
12352 in control flow graph) + 2;
12356 Having said that the industry standard is 10, you should be aware that in
12357 some cases it be may unavoidable to have a complexity level of less than
12359 For example if you have switch statement with more than 10 case labels,
12360 each case label adds one to the complexity level.
12361 The complexity level is by no means an absolute measure of the algorithmic
12362 complexity of the function, it does however provide a good starting point
12363 for which functions you might look at for further optimization.
12369 Here are a few guidelines that will help the compiler generate more efficient
12370 code, some of the tips are specific to this compiler others are generally
12371 good programming practice.
12374 Use the smallest data type to represent your data-value.
12375 If it is known in advance that the value is going to be less than 256 then
12376 use an 'unsigned char' instead of a 'short' or 'int'.
12379 Use unsigned when it is known in advance that the value is not going to
12381 This helps especially if you are doing division or multiplication.
12384 NEVER jump into a LOOP.
12387 Declare the variables to be local whenever possible, especially loop control
12388 variables (induction).
12391 Since the compiler does not always do implicit integral promotion, the programme
12392 r should do an explicit cast when integral promotion is required.
12395 Reducing the size of division, multiplication & modulus operations can reduce
12396 code size substantially.
12397 Take the following code for example.
12403 foobar(unsigned int p1, unsigned char ch)
12411 unsigned char ch1 = p1 % ch ;
12422 For the modulus operation the variable ch will be promoted to unsigned int
12423 first then the modulus operation will be performed (this will lead to a
12424 call to support routine _moduint()), and the result will be casted to a
12426 If the code is changed to
12431 foobar(unsigned int p1, unsigned char ch)
12439 unsigned char ch1 = (unsigned char)p1 % ch ;
12450 It would substantially reduce the code generated (future versions of the
12451 compiler will be smart enough to detect such optimization opportunities).
12455 Notes on MCS51 memory
12456 \begin_inset LatexCommand \index{MCS51 memory}
12463 The 8051 family of microcontrollers have a minimum of 128 bytes of internal
12464 RAM memory which is structured as follows
12468 - Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R0 to R7,
12471 - Bytes 20-2F - 16 bytes to hold 128 bit variables and,
12473 - Bytes 30-7F - 80 bytes for general purpose use.
12478 Additionally some members of the MCS51 family may have up to 128 bytes of
12479 additional, indirectly addressable, internal RAM memory (
12484 Furthermore, some chips may have some built in external memory (
12488 ) which should not be confused with the internal, directly addressable RAM
12494 Usually this built in
12498 memory has to be activated before using it (you can probably find this
12499 information on the datasheet of the microcontroller your are using).
12502 Normally SDCC will only use the first bank
12503 \begin_inset LatexCommand \index{bank}
12507 of registers (register bank 0), but it is possible to specify that other
12508 banks of registers should be used in interrupt
12509 \begin_inset LatexCommand \index{interrupt}
12514 By default, the compiler will place the stack after the last byte of allocated
12515 memory for variables.
12516 For example, if the first 2 banks of registers are used, and only four
12521 variables, it will position the base of the internal stack at address 20
12523 This implies that as the stack
12524 \begin_inset LatexCommand \index{stack}
12528 grows, it will use up the remaining register banks, and the 16 bytes used
12529 by the 128 bit variables, and 80 bytes for general purpose use.
12530 If any bit variables are used, the data variables will be placed after
12531 the byte holding the last bit variable.
12532 For example, if register banks 0 and 1 are used, and there are 9 bit variables
12537 variables will be placed starting at address 0x22.
12549 \begin_inset LatexCommand \index{-\/-data-loc}
12553 to specify the start address of the
12567 -iram-size to specify the size of the total internal RAM (
12579 By default the 8051 linker will place the stack after the last byte of data
12592 \begin_inset LatexCommand \index{-\/-stack-loc}
12596 allows you to specify the start of the stack, i.e.
12597 you could start it after any data in the general purpose area.
12598 If your microcontroller has additional indirectly addressable internal
12603 ) you can place the stack on it.
12604 You may also need to use -
12615 \begin_inset LatexCommand \index{-\/-data-loc}
12619 to set the start address of the external RAM (
12634 \begin_inset LatexCommand \index{-\/-data-loc}
12638 to specify its size.
12639 Same goes for the code memory, using -
12650 \begin_inset LatexCommand \index{-\/-data-loc}
12665 \begin_inset LatexCommand \index{-\/-data-loc}
12670 If in doubt, don't specify any options and see if the resulting memory
12671 layout is appropriate, then you can adjust it.
12674 The 8051 linker generates two files with memory allocation information.
12675 The first, with extension .map shows all the variables and segments.
12676 The second with extension .mem shows the final memory layout.
12677 The linker will complaint either if memory segments overlap, there is not
12678 enough memory, or there is not enough space for stack.
12679 If you get any linking warnings and/or errors related to stack or segments
12680 allocation, take a look at either the .map or .mem files to find out what
12682 The .mem file may even suggest a solution to the problem.
12686 \begin_inset LatexCommand \index{Tools}
12690 included in the distribution
12694 \begin_inset Tabular
12695 <lyxtabular version="3" rows="12" columns="3">
12697 <column alignment="center" valignment="top" leftline="true" width="0pt">
12698 <column alignment="center" valignment="top" leftline="true" width="0pt">
12699 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
12700 <row topline="true" bottomline="true">
12701 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12709 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12717 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12726 <row topline="true">
12727 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12735 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12740 Simulator for various architectures
12743 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12752 <row topline="true">
12753 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12761 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12766 header file conversion
12769 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12774 sdcc/support/scripts
12778 <row topline="true">
12779 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12787 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12792 header file conversion
12795 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12800 sdcc/support/scripts
12804 <row topline="true">
12805 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12813 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12821 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12839 <row topline="true">
12840 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12848 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12856 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12874 <row topline="true">
12875 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12883 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12891 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12909 <row topline="true">
12910 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12918 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12926 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12944 <row topline="true">
12945 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12953 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12961 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
12979 <row topline="true">
12980 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12988 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
12996 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13014 <row topline="true">
13015 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13023 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13031 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13049 <row topline="true" bottomline="true">
13050 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13058 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13066 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13091 Related open source tools
13092 \begin_inset LatexCommand \index{Related tools}
13100 \begin_inset Tabular
13101 <lyxtabular version="3" rows="7" columns="3">
13103 <column alignment="center" valignment="top" leftline="true" width="0pt">
13104 <column alignment="center" valignment="top" leftline="true" width="0pt">
13105 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
13106 <row topline="true" bottomline="true">
13107 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13115 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13123 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13132 <row topline="true">
13133 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13139 \begin_inset LatexCommand \index{gpsim}
13146 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13154 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13160 \begin_inset LatexCommand \url{http://www.dattalo.com/gnupic/gpsim.html}
13168 <row topline="true">
13169 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13175 \begin_inset LatexCommand \index{srecord}
13182 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13187 Object file conversion, checksumming, ...
13190 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13196 \begin_inset LatexCommand \url{http://srecord.sourceforge.net/}
13204 <row topline="true">
13205 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13211 \begin_inset LatexCommand \index{objdump}
13218 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13223 Object file conversion, ...
13226 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13231 Part of binutils (should be there anyway)
13235 <row topline="true">
13236 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13242 \begin_inset LatexCommand \index{doxygen}
13249 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13254 Source code documentation system
13257 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13263 \begin_inset LatexCommand \url{http://www.doxygen.org}
13271 <row topline="true">
13272 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13278 \begin_inset LatexCommand \index{splint}
13285 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13290 Statically checks c sources
13293 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13299 \begin_inset LatexCommand \url{http://www.splint.org}
13307 <row topline="true" bottomline="true">
13308 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13314 \begin_inset LatexCommand \index{ddd}
13321 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13326 Debugger, serves nicely as GUI to sdcdb
13327 \begin_inset LatexCommand \index{sdcdb}
13334 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13340 \begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}
13355 Related documentation / recommended reading
13359 \begin_inset Tabular
13360 <lyxtabular version="3" rows="5" columns="3">
13362 <column alignment="center" valignment="top" leftline="true" width="0pt">
13363 <column alignment="center" valignment="top" leftline="true" width="0pt">
13364 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
13365 <row topline="true" bottomline="true">
13366 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13374 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13382 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13391 <row topline="true">
13392 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13402 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13407 Advanced Compiler Design and Implementation
13410 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13419 <row topline="true">
13420 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13437 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13443 \begin_inset LatexCommand \index{C Reference card}
13450 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13456 \begin_inset LatexCommand \url{http://www.refcards.com/about/c.html}
13464 <row topline="true">
13465 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13470 test_suite_spec.pdf
13473 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13478 sdcc regression test
13479 \begin_inset LatexCommand \index{Regression test}
13486 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13495 <row topline="true" bottomline="true">
13496 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13522 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13527 sdcc internal documentation
13530 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13546 Retargetting for other MCUs.
13549 The issues for retargetting the compiler are far too numerous to be covered
13551 What follows is a brief description of each of the seven phases of the
13552 compiler and its MCU dependency.
13555 Parsing the source and building the annotated parse tree.
13556 This phase is largely MCU independent (except for the language extensions).
13557 Syntax & semantic checks are also done in this phase, along with some initial
13558 optimizations like back patching labels and the pattern matching optimizations
13559 like bit-rotation etc.
13562 The second phase involves generating an intermediate code which can be easy
13563 manipulated during the later phases.
13564 This phase is entirely MCU independent.
13565 The intermediate code generation assumes the target machine has unlimited
13566 number of registers, and designates them with the name iTemp.
13567 The compiler can be made to dump a human readable form of the code generated
13581 This phase does the bulk of the standard optimizations and is also MCU independe
13583 This phase can be broken down into several sub-phases:
13587 Break down intermediate code (iCode) into basic blocks.
13589 Do control flow & data flow analysis on the basic blocks.
13591 Do local common subexpression elimination, then global subexpression elimination
13593 Dead code elimination
13597 If loop optimizations caused any changes then do 'global subexpression eliminati
13598 on' and 'dead code elimination' again.
13601 This phase determines the live-ranges; by live range I mean those iTemp
13602 variables defined by the compiler that still survive after all the optimization
13604 Live range analysis
13605 \begin_inset LatexCommand \index{Live range analysis}
13609 is essential for register allocation, since these computation determines
13610 which of these iTemps will be assigned to registers, and for how long.
13613 Phase five is register allocation.
13614 There are two parts to this process.
13618 The first part I call 'register packing' (for lack of a better term).
13619 In this case several MCU specific expression folding is done to reduce
13624 The second part is more MCU independent and deals with allocating registers
13625 to the remaining live ranges.
13626 A lot of MCU specific code does creep into this phase because of the limited
13627 number of index registers available in the 8051.
13630 The Code generation phase is (unhappily), entirely MCU dependent and very
13631 little (if any at all) of this code can be reused for other MCU.
13632 However the scheme for allocating a homogenized assembler operand for each
13633 iCode operand may be reused.
13636 As mentioned in the optimization section the peep-hole optimizer is rule
13637 based system, which can reprogrammed for other MCUs.
13641 \begin_inset LatexCommand \index{sdcdb}
13645 - Source Level Debugger
13646 \begin_inset LatexCommand \index{Debugger}
13653 SDCC is distributed with a source level debugger.
13654 The debugger uses a command line interface, the command repertoire of the
13655 debugger has been kept as close to gdb
13656 \begin_inset LatexCommand \index{gdb}
13660 (the GNU debugger) as possible.
13661 The configuration and build process is part of the standard compiler installati
13662 on, which also builds and installs the debugger in the target directory
13663 specified during configuration.
13664 The debugger allows you debug BOTH at the C source and at the ASM source
13668 Compiling for Debugging
13671 The \SpecialChar \-
13673 debug option must be specified for all files for which debug information
13674 is to be generated.
13675 The complier generates a .adb file for each of these files.
13676 The linker creates the .cdb file from the .adb files and the address information.
13677 This .cdb is used by the debugger.
13680 How the Debugger Works
13693 -debug option is specified the compiler generates extra symbol information
13694 some of which are put into the the assembler source and some are put into
13696 Then the linker creates the .cdb file from the individual .adb files with
13697 the address information for the symbols.
13698 The debugger reads the symbolic information generated by the compiler &
13699 the address information generated by the linker.
13700 It uses the SIMULATOR (Daniel's S51) to execute the program, the program
13701 execution is controlled by the debugger.
13702 When a command is issued for the debugger, it translates it into appropriate
13703 commands for the simulator.
13706 Starting the Debugger
13709 The debugger can be started using the following command line.
13710 (Assume the file you are debugging has the file name foo).
13724 The debugger will look for the following files.
13727 foo.c - the source file.
13730 foo.cdb - the debugger symbol information file.
13733 foo.ihx - the Intel hex format
13734 \begin_inset LatexCommand \index{Intel hex format}
13741 Command Line Options.
13754 -directory=<source file directory> this option can used to specify the directory
13756 The debugger will look into the directory list specified for source, cdb
13758 The items in the directory list must be separated by ':', e.g.
13759 if the source files can be in the directories /home/src1 and /home/src2,
13770 -directory option should be -
13780 -directory=/home/src1:/home/src2.
13781 Note there can be no spaces in the option.
13785 -cd <directory> - change to the <directory>.
13788 -fullname - used by GUI front ends.
13791 -cpu <cpu-type> - this argument is passed to the simulator please see the
13792 simulator docs for details.
13795 -X <Clock frequency > this options is passed to the simulator please see
13796 the simulator docs for details.
13799 -s <serial port file> passed to simulator see the simulator docs for details.
13802 -S <serial in,out> passed to simulator see the simulator docs for details.
13808 As mention earlier the command interface for the debugger has been deliberately
13809 kept as close the GNU debugger gdb, as possible.
13810 This will help the integration with existing graphical user interfaces
13811 (like ddd, xxgdb or xemacs) existing for the GNU debugger.
13812 \layout Subsubsection
13814 break [line | file:line | function | file:function]
13817 Set breakpoint at specified line or function:
13826 sdcdb>break foo.c:100
13828 sdcdb>break funcfoo
13830 sdcdb>break foo.c:funcfoo
13831 \layout Subsubsection
13833 clear [line | file:line | function | file:function ]
13836 Clear breakpoint at specified line or function:
13845 sdcdb>clear foo.c:100
13847 sdcdb>clear funcfoo
13849 sdcdb>clear foo.c:funcfoo
13850 \layout Subsubsection
13855 Continue program being debugged, after breakpoint.
13856 \layout Subsubsection
13861 Execute till the end of the current function.
13862 \layout Subsubsection
13867 Delete breakpoint number 'n'.
13868 If used without any option clear ALL user defined break points.
13869 \layout Subsubsection
13871 info [break | stack | frame | registers ]
13874 info break - list all breakpoints
13877 info stack - show the function call stack.
13880 info frame - show information about the current execution frame.
13883 info registers - show content of all registers.
13884 \layout Subsubsection
13889 Step program until it reaches a different source line.
13890 \layout Subsubsection
13895 Step program, proceeding through subroutine calls.
13896 \layout Subsubsection
13901 Start debugged program.
13902 \layout Subsubsection
13907 Print type information of the variable.
13908 \layout Subsubsection
13913 print value of variable.
13914 \layout Subsubsection
13919 load the given file name.
13920 Note this is an alternate method of loading file for debugging.
13921 \layout Subsubsection
13926 print information about current frame.
13927 \layout Subsubsection
13932 Toggle between C source & assembly source.
13933 \layout Subsubsection
13935 ! simulator command
13938 Send the string following '!' to the simulator, the simulator response is
13940 Note the debugger does not interpret the command being sent to the simulator,
13941 so if a command like 'go' is sent the debugger can loose its execution
13942 context and may display incorrect values.
13943 \layout Subsubsection
13950 My name is Bobby Brown"
13953 Interfacing with XEmacs
13954 \begin_inset LatexCommand \index{XEmacs}
13959 \begin_inset LatexCommand \index{Emacs}
13966 Two files (in emacs lisp) are provided for the interfacing with XEmacs,
13967 sdcdb.el and sdcdbsrc.el.
13968 These two files can be found in the $(prefix)/bin directory after the installat
13970 These files need to be loaded into XEmacs for the interface to work.
13971 This can be done at XEmacs startup time by inserting the following into
13972 your '.xemacs' file (which can be found in your HOME directory):
13978 (load-file sdcdbsrc.el)
13984 .xemacs is a lisp file so the () around the command is REQUIRED.
13985 The files can also be loaded dynamically while XEmacs is running, set the
13986 environment variable 'EMACSLOADPATH' to the installation bin directory
13987 (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
13988 To start the interface enter the following command:
14002 You will prompted to enter the file name to be debugged.
14007 The command line options that are passed to the simulator directly are bound
14008 to default values in the file sdcdbsrc.el.
14009 The variables are listed below, these values maybe changed as required.
14012 sdcdbsrc-cpu-type '51
14015 sdcdbsrc-frequency '11059200
14018 sdcdbsrc-serial nil
14021 The following is a list of key mapping for the debugger interface.
14029 ;; Current Listing ::
14031 ;;key\SpecialChar ~
14046 binding\SpecialChar ~
14070 ;;---\SpecialChar ~
14085 ------\SpecialChar ~
14125 sdcdb-next-from-src\SpecialChar ~
14151 sdcdb-back-from-src\SpecialChar ~
14177 sdcdb-cont-from-src\SpecialChar ~
14187 SDCDB continue command
14203 sdcdb-step-from-src\SpecialChar ~
14229 sdcdb-whatis-c-sexp\SpecialChar ~
14239 SDCDB ptypecommand for data at
14303 sdcdbsrc-delete\SpecialChar ~
14317 SDCDB Delete all breakpoints if no arg
14365 given or delete arg (C-u arg x)
14381 sdcdbsrc-frame\SpecialChar ~
14396 SDCDB Display current frame if no arg,
14445 given or display frame arg
14510 sdcdbsrc-goto-sdcdb\SpecialChar ~
14520 Goto the SDCDB output buffer
14536 sdcdb-print-c-sexp\SpecialChar ~
14547 SDCDB print command for data at
14611 sdcdbsrc-goto-sdcdb\SpecialChar ~
14621 Goto the SDCDB output buffer
14637 sdcdbsrc-mode\SpecialChar ~
14653 Toggles Sdcdbsrc mode (turns it off)
14657 ;; C-c C-f\SpecialChar ~
14665 sdcdb-finish-from-src\SpecialChar ~
14673 SDCDB finish command
14677 ;; C-x SPC\SpecialChar ~
14685 sdcdb-break\SpecialChar ~
14703 Set break for line with point
14705 ;; ESC t\SpecialChar ~
14715 sdcdbsrc-mode\SpecialChar ~
14731 Toggle Sdcdbsrc mode
14733 ;; ESC m\SpecialChar ~
14743 sdcdbsrc-srcmode\SpecialChar ~
14767 The Z80 and gbz80 port
14770 SDCC can target both the Zilog Z80 and the Nintendo Gameboy's Z80-like gbz80.
14771 The port is incomplete - long support is incomplete (mul, div and mod are
14772 unimplemented), and both float and bitfield support is missing.
14773 Apart from that the code generated is correct.
14776 As always, the code is the authoritave reference - see z80/ralloc.c and z80/gen.c.
14777 The stack frame is similar to that generated by the IAR Z80 compiler.
14778 IX is used as the base pointer, HL is used as a temporary register, and
14779 BC and DE are available for holding variables.
14780 IY is currently unused.
14781 Return values are stored in HL.
14782 One bad side effect of using IX as the base pointer is that a functions
14783 stack frame is limited to 127 bytes - this will be fixed in a later version.
14787 \begin_inset LatexCommand \index{Support}
14794 SDCC has grown to be a large project.
14795 The compiler alone (without the preprocessor, assembler and linker) is
14796 about 40,000 lines of code (blank stripped).
14797 The open source nature of this project is a key to its continued growth
14799 You gain the benefit and support of many active software developers and
14801 Is SDCC perfect? No, that's why we need your help.
14802 The developers take pride in fixing reported bugs.
14803 You can help by reporting the bugs and helping other SDCC users.
14804 There are lots of ways to contribute, and we encourage you to take part
14805 in making SDCC a great software package.
14809 The SDCC project is hosted on the sdcc sourceforge site at
14810 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}
14815 You'll find the complete set of mailing lists
14816 \begin_inset LatexCommand \index{Mailing list}
14820 , forums, bug reporting system, patch submission
14821 \begin_inset LatexCommand \index{Patch submission}
14826 \begin_inset LatexCommand \index{download}
14830 area and cvs code repository
14831 \begin_inset LatexCommand \index{cvs code repository}
14839 \begin_inset LatexCommand \index{Bugs}
14844 \begin_inset LatexCommand \index{Reporting bugs}
14851 The recommended way of reporting bugs is using the infrastructure of the
14853 You can follow the status of bug reports there and have an overview about
14857 Bug reports are automatically forwarded to the developer mailing list and
14858 will be fixed ASAP.
14859 When reporting a bug, it is very useful to include a small test program
14860 (the smaller the better) which reproduces the problem.
14861 If you can isolate the problem by looking at the generated assembly code,
14862 this can be very helpful.
14863 Compiling your program with the -
14874 \begin_inset LatexCommand \index{-\/-dumpall}
14878 option can sometimes be useful in locating optimization problems.
14879 When reporting a bug please maker sure you:
14882 Attach the code you are compiling with SDCC.
14886 Specify the exact command you use to run SDCC, or attach your Makefile.
14890 Specify the SDCC version (type "sdcc -v"), your platform, and operating
14895 Provide an exact copy of any error message or incorrect output.
14899 Please attempt to include these 4 important parts, as applicable, in all
14900 requests for support or when reporting any problems or bugs with SDCC.
14901 Though this will make your message lengthy, it will greatly improve your
14902 chance that SDCC users and developers will be able to help you.
14903 Some SDCC developers are frustrated by bug reports without code provided
14904 that they can use to reproduce and ultimately fix the problem, so please
14905 be sure to provide sample code if you are reporting a bug!
14908 Please have a short check that you are using a recent version of SDCC and
14909 the bug is not yet known.
14910 This is the link for reporting bugs:
14911 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=100599}
14918 Requesting Features
14919 \begin_inset LatexCommand \index{Feature request}
14924 \begin_inset LatexCommand \index{Requesting features}
14931 Like bug reports feature requests are forwarded to the developer mailing
14933 This is the link for requesting features:
14934 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
14944 These links should take you directly to the
14945 \begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}
14955 Traffic on sdcc-devel and sdcc-user is about 100 mails/month each not counting
14956 automated messages (mid 2003)
14960 \begin_inset LatexCommand \url[Forums]{http://sourceforge.net/forum/?group_id=599}
14964 , lists and forums are archived so if you are lucky someone already had
14969 \begin_inset LatexCommand \index{Changelog}
14976 You can follow the status of the cvs version
14977 \begin_inset LatexCommand \index{version}
14981 of SDCC by watching the file
14982 \begin_inset LatexCommand \htmlurl[ChangeLog]{http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/*checkout*/sdcc/sdcc/ChangeLog?rev=HEAD&content-type=text/plain}
14986 in the cvs-repository.
14990 \begin_inset LatexCommand \index{Release policy}
14997 Historically there often were long delays between official releases and
14998 the sourceforge download area tends to get not updated at all.
14999 Current excuses might refer to problems with live range analysis, but if
15000 this is fixed, the next problem rising is that another excuse will have
15002 Kidding aside, we have to get better there! On the other hand there are
15003 daily snapshots available at
15004 \begin_inset LatexCommand \htmlurl[snap]{http://sdcc.sourceforge.net/snap.php}
15008 , and you can always built the very last version (hopefully with many bugs
15009 fixed, and features added) from the source code available at
15010 \begin_inset LatexCommand \htmlurl[Source]{http://sdcc.sourceforge.net/snap.php#Source}
15018 \begin_inset LatexCommand \index{Examples}
15025 You'll find some small examples in the directory sdcc/device/examples/
15028 Maybe we should include some links to real world applications.
15029 Preferably pointer to pointers (one for each architecture) so this stays
15034 \begin_inset LatexCommand \index{Quality control}
15041 The compiler is passed through nightly compile and build checks.
15047 \begin_inset LatexCommand \index{Regression test}
15051 check that SDCC itself compiles flawlessly on several platforms and checks
15052 the quality of the code generated by SDCC by running the code through simulator
15054 There is a separate document
15057 \begin_inset LatexCommand \index{Test suite}
15066 You'll find the test code in the directory
15068 sdcc/support/regression
15071 You can run these tests manually by running
15075 in this directory (or f.e.
15080 if you don't want to run the complete tests).
15081 The test code might also be interesting if you want to look for examples
15082 \begin_inset LatexCommand \index{Examples}
15086 checking corner cases of SDCC or if you plan to submit patches
15087 \begin_inset LatexCommand \index{Patch submission}
15094 The pic port uses a different set of regression tests, you'll find them
15097 sdcc/src/regression
15103 \begin_inset LatexCommand \index{Compiler internals}
15110 The anatomy of the compiler
15115 This is an excerpt from an article published in Circuit Cellar Magazine
15117 It's a little outdated (the compiler is much more efficient now and user/develo
15118 per friendly), but pretty well exposes the guts of it all.
15124 The current version of SDCC can generate code for Intel 8051 and Z80 MCU.
15125 It is fairly easy to retarget for other 8-bit MCU.
15126 Here we take a look at some of the internals of the compiler.
15131 \begin_inset LatexCommand \index{Parsing}
15138 Parsing the input source file and creating an AST (Annotated Syntax Tree
15139 \begin_inset LatexCommand \index{Annotated syntax tree}
15144 This phase also involves propagating types (annotating each node of the
15145 parse tree with type information) and semantic analysis.
15146 There are some MCU specific parsing rules.
15147 For example the storage classes, the extended storage classes are MCU specific
15148 while there may be a xdata storage class for 8051 there is no such storage
15149 class for z80 or Atmel AVR.
15150 SDCC allows MCU specific storage class extensions, i.e.
15151 xdata will be treated as a storage class specifier when parsing 8051 C
15152 code but will be treated as a C identifier when parsing z80 or ATMEL AVR
15157 \begin_inset LatexCommand \index{iCode}
15164 Intermediate code generation.
15165 In this phase the AST is broken down into three-operand form (iCode).
15166 These three operand forms are represented as doubly linked lists.
15167 ICode is the term given to the intermediate form generated by the compiler.
15168 ICode example section shows some examples of iCode generated for some simple
15169 C source functions.
15173 \begin_inset LatexCommand \index{Optimizations}
15180 Bulk of the target independent optimizations is performed in this phase.
15181 The optimizations include constant propagation, common sub-expression eliminati
15182 on, loop invariant code movement, strength reduction of loop induction variables
15183 and dead-code elimination.
15186 Live range analysis
15187 \begin_inset LatexCommand \index{Live range analysis}
15194 During intermediate code generation phase, the compiler assumes the target
15195 machine has infinite number of registers and generates a lot of temporary
15197 The live range computation determines the lifetime of each of these compiler-ge
15198 nerated temporaries.
15199 A picture speaks a thousand words.
15200 ICode example sections show the live range annotations for each of the
15202 It is important to note here, each iCode is assigned a number in the order
15203 of its execution in the function.
15204 The live ranges are computed in terms of these numbers.
15205 The from number is the number of the iCode which first defines the operand
15206 and the to number signifies the iCode which uses this operand last.
15209 Register Allocation
15210 \begin_inset LatexCommand \index{Register allocation}
15217 The register allocation determines the type and number of registers needed
15219 In most MCUs only a few registers can be used for indirect addressing.
15220 In case of 8051 for example the registers R0 & R1 can be used to indirectly
15221 address the internal ram and DPTR to indirectly address the external ram.
15222 The compiler will try to allocate the appropriate register to pointer variables
15224 ICode example section shows the operands annotated with the registers assigned
15226 The compiler will try to keep operands in registers as much as possible;
15227 there are several schemes the compiler uses to do achieve this.
15228 When the compiler runs out of registers the compiler will check to see
15229 if there are any live operands which is not used or defined in the current
15230 basic block being processed, if there are any found then it will push that
15231 operand and use the registers in this block, the operand will then be popped
15232 at the end of the basic block.
15236 There are other MCU specific considerations in this phase.
15237 Some MCUs have an accumulator; very short-lived operands could be assigned
15238 to the accumulator instead of general-purpose register.
15244 Figure II gives a table of iCode operations supported by the compiler.
15245 The code generation involves translating these operations into corresponding
15246 assembly code for the processor.
15247 This sounds overly simple but that is the essence of code generation.
15248 Some of the iCode operations are generated on a MCU specific manner for
15249 example, the z80 port does not use registers to pass parameters so the
15250 SEND and RECV iCode operations will not be generated, and it also does
15251 not support JUMPTABLES.
15258 <Where is Figure II ?>
15262 \begin_inset LatexCommand \index{iCode}
15269 This section shows some details of iCode.
15270 The example C code does not do anything useful; it is used as an example
15271 to illustrate the intermediate code generated by the compiler.
15283 /* This function does nothing useful.
15290 for the purpose of explaining iCode */
15293 short function (data int *x)
15301 short i=10; /* dead initialization eliminated */
15306 short sum=10; /* dead initialization eliminated */
15319 while (*x) *x++ = *p++;
15333 /* compiler detects i,j to be induction variables */
15337 for (i = 0, j = 10 ; i < 10 ; i++, j
15363 mul += i * 3; /* this multiplication remains */
15369 gint += j * 3;/* this multiplication changed to addition */
15383 In addition to the operands each iCode contains information about the filename
15384 and line it corresponds to in the source file.
15385 The first field in the listing should be interpreted as follows:
15390 Filename(linenumber: iCode Execution sequence number : ICode hash table
15391 key : loop depth of the iCode).
15396 Then follows the human readable form of the ICode operation.
15397 Each operand of this triplet form can be of three basic types a) compiler
15398 generated temporary b) user defined variable c) a constant value.
15399 Note that local variables and parameters are replaced by compiler generated
15402 \begin_inset LatexCommand \index{Live range analysis}
15406 are computed only for temporaries (i.e.
15407 live ranges are not computed for global variables).
15409 \begin_inset LatexCommand \index{Register allocation}
15413 are allocated for temporaries only.
15414 Operands are formatted in the following manner:
15419 Operand Name [lr live-from : live-to ] { type information } [ registers
15425 As mentioned earlier the live ranges are computed in terms of the execution
15426 sequence number of the iCodes, for example
15428 the iTemp0 is live from (i.e.
15429 first defined in iCode with execution sequence number 3, and is last used
15430 in the iCode with sequence number 5).
15431 For induction variables such as iTemp21 the live range computation extends
15432 the lifetime from the start to the end of the loop.
15434 The register allocator used the live range information to allocate registers,
15435 the same registers may be used for different temporaries if their live
15436 ranges do not overlap, for example r0 is allocated to both iTemp6 and to
15437 iTemp17 since their live ranges do not overlap.
15438 In addition the allocator also takes into consideration the type and usage
15439 of a temporary, for example itemp6 is a pointer to near space and is used
15440 as to fetch data from (i.e.
15441 used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer registers (r0).
15442 Some short lived temporaries are allocated to special registers which have
15443 meaning to the code generator e.g.
15444 iTemp13 is allocated to a pseudo register CC which tells the back end that
15445 the temporary is used only for a conditional jump the code generation makes
15446 use of this information to optimize a compare and jump ICode.
15448 There are several loop optimizations
15449 \begin_inset LatexCommand \index{Loop optimization}
15453 performed by the compiler.
15454 It can detect induction variables iTemp21(i) and iTemp23(j).
15455 Also note the compiler does selective strength reduction
15456 \begin_inset LatexCommand \index{Strength reduction}
15461 the multiplication of an induction variable in line 18 (gint = j * 3) is
15462 changed to addition, a new temporary iTemp17 is allocated and assigned
15463 a initial value, a constant 3 is then added for each iteration of the loop.
15464 The compiler does not change the multiplication
15465 \begin_inset LatexCommand \index{Multiplication}
15469 in line 17 however since the processor does support an 8 * 8 bit multiplication.
15471 Note the dead code elimination
15472 \begin_inset LatexCommand \index{Dead-code elimination}
15476 optimization eliminated the dead assignments in line 7 & 8 to I and sum
15484 Sample.c (5:1:0:0) _entry($9) :
15489 Sample.c(5:2:1:0) proc _function [lr0:0]{function short}
15494 Sample.c(11:3:2:0) iTemp0 [lr3:5]{_near * int}[r2] = recv
15499 Sample.c(11:4:53:0) preHeaderLbl0($11) :
15504 Sample.c(11:5:55:0) iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near
15510 Sample.c(11:6:5:1) _whilecontinue_0($1) :
15515 Sample.c(11:7:7:1) iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near *
15521 Sample.c(11:8:8:1) if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
15526 Sample.c(11:9:14:1) iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far
15532 Sample.c(11:10:15:1) _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2
15538 Sample.c(11:13:18:1) iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far
15544 Sample.c(11:14:19:1) *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int
15550 Sample.c(11:15:12:1) iTemp6 [lr5:16]{_near * int}[r0] = iTemp6 [lr5:16]{_near
15551 * int}[r0] + 0x2 {short}
15556 Sample.c(11:16:20:1) goto _whilecontinue_0($1)
15561 Sample.c(11:17:21:0)_whilebreak_0($3) :
15566 Sample.c(12:18:22:0) iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
15571 Sample.c(13:19:23:0) iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
15576 Sample.c(15:20:54:0)preHeaderLbl1($13) :
15581 Sample.c(15:21:56:0) iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
15586 Sample.c(15:22:57:0) iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
15591 Sample.c(15:23:58:0) iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
15596 Sample.c(15:24:26:1)_forcond_0($4) :
15601 Sample.c(15:25:27:1) iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4]
15607 Sample.c(15:26:28:1) if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
15612 Sample.c(16:27:31:1) iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2]
15613 + ITemp21 [lr21:38]{short}[r4]
15618 Sample.c(17:29:33:1) iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4]
15624 Sample.c(17:30:34:1) iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3]
15625 + iTemp15 [lr29:30]{short}[r1]
15630 Sample.c(18:32:36:1:1) iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7
15636 Sample.c(18:33:37:1) _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{
15642 Sample.c(15:36:42:1) iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4]
15648 Sample.c(15:37:45:1) iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5
15654 Sample.c(19:38:47:1) goto _forcond_0($4)
15659 Sample.c(19:39:48:0)_forbreak_0($7) :
15664 Sample.c(20:40:49:0) iTemp24 [lr40:41]{short}[DPTR] = iTemp2 [lr18:40]{short}[r2]
15665 + ITemp11 [lr19:40]{short}[r3]
15670 Sample.c(20:41:50:0) ret iTemp24 [lr40:41]{short}
15675 Sample.c(20:42:51:0)_return($8) :
15680 Sample.c(20:43:52:0) eproc _function [lr0:0]{ ia0 re0 rm0}{function short}
15686 Finally the code generated for this function:
15727 ; ----------------------------------------------
15732 ; function function
15737 ; ----------------------------------------------
15747 ; iTemp0 [lr3:5]{_near * int}[r2] = recv
15759 ; iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near * int}[r2]
15771 ;_whilecontinue_0($1) :
15781 ; iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near * int}[r0]]
15786 ; if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
15845 ; iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far * int}
15864 ; _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2 {short}
15911 ; iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far * int}[DPTR]]
15951 ; *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int}[r2 r3]
15977 ; iTemp6 [lr5:16]{_near * int}[r0] =
15982 ; iTemp6 [lr5:16]{_near * int}[r0] +
15999 ; goto _whilecontinue_0($1)
16011 ; _whilebreak_0($3) :
16021 ; iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
16033 ; iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
16045 ; iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
16057 ; iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
16076 ; iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
16105 ; iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4] < 0xa {short}
16110 ; if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
16155 ; iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2] +
16160 ; iTemp21 [lr21:38]{short}[r4]
16186 ; iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4] * 0x3 {short}
16219 ; iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3] +
16224 ; iTemp15 [lr29:30]{short}[r1]
16243 ; iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7 r0]- 0x3 {short}
16290 ; _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{int}[r7 r0]
16337 ; iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4] + 0x1 {short}
16349 ; iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5 r6]- 0x1 {short}
16363 cjne r5,#0xff,00104$
16375 ; goto _forcond_0($4)
16387 ; _forbreak_0($7) :
16397 ; ret iTemp24 [lr40:41]{short}
16440 A few words about basic block successors, predecessors and dominators
16443 Successors are basic blocks
16444 \begin_inset LatexCommand \index{Basic blocks}
16448 that might execute after this basic block.
16450 Predecessors are basic blocks that might execute before reaching this basic
16453 Dominators are basic blocks that WILL execute before reaching this basic
16479 a) succList of [BB2] = [BB4], of [BB3] = [BB4], of [BB1] = [BB2,BB3]
16482 b) predList of [BB2] = [BB1], of [BB3] = [BB1], of [BB4] = [BB2,BB3]
16485 c) domVect of [BB4] = BB1 ...
16486 here we are not sure if BB2 or BB3 was executed but we are SURE that BB1
16494 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net#Who}
16504 Thanks to all the other volunteer developers who have helped with coding,
16505 testing, web-page creation, distribution sets, etc.
16506 You know who you are :-)
16513 This document was initially written by Sandeep Dutta
16516 All product names mentioned herein may be trademarks
16517 \begin_inset LatexCommand \index{Trademarks}
16521 of their respective companies.
16528 To avoid confusion, the installation and building options for sdcc itself
16529 (chapter 2) are not part of the index.
16533 \begin_inset LatexCommand \printindex{}