1 #LyX 1.2 created this file. For more info see http://www.lyx.org/
15 \use_numerical_citations 0
16 \paperorientation portrait
19 \paragraph_separation indent
21 \quotes_language swedish
29 Please note: double dashed longoptions (e.g.
30 --version) need three dashes in this document to be visable in html and
34 SDCC Compiler User Guide
38 \begin_inset LatexCommand \tableofcontents{}
55 is a Freeware, retargettable, optimizing ANSI-C compiler by
59 designed for 8 bit Microprocessors.
60 The current version targets Intel MCS51 based Microprocessors(8051,8052,
61 etc), Zilog Z80 based MCUs, and the Dallas DS80C390 variant.
62 It can be retargetted for other microprocessors, support for PIC, AVR and
63 186 is under development.
64 The entire source code for the compiler is distributed under GPL.
65 SDCC uses ASXXXX & ASLINK, a Freeware, retargettable assembler & linker.
66 SDCC has extensive language extensions suitable for utilizing various microcont
67 rollers and underlying hardware effectively.
72 In addition to the MCU specific optimizations SDCC also does a host of standard
76 global sub expression elimination,
79 loop optimizations (loop invariant, strength reduction of induction variables
83 constant folding & propagation,
99 For the back-end SDCC uses a global register allocation scheme which should
100 be well suited for other 8 bit MCUs.
105 The peep hole optimizer uses a rule based substitution mechanism which is
111 Supported data-types are:
114 char (8 bits, 1 byte),
117 short and int (16 bits, 2 bytes),
120 long (32 bit, 4 bytes)
127 The compiler also allows
129 inline assembler code
131 to be embedded anywhere in a function.
132 In addition, routines developed in assembly can also be called.
136 SDCC also provides an option (--cyclomatic) to report the relative complexity
138 These functions can then be further optimized, or hand coded in assembly
144 SDCC also comes with a companion source level debugger SDCDB, the debugger
145 currently uses ucSim a freeware simulator for 8051 and other micro-controllers.
150 The latest version can be downloaded from
151 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
163 All packages used in this compiler system are
171 ; source code for all the sub-packages (pre-processor, assemblers, linkers
172 etc) is distributed with the package.
173 This documentation is maintained using a freeware word processor (LyX).
175 This program is free software; you can redistribute it and/or modify it
176 under the terms of the GNU General Public License as published by the Free
177 Software Foundation; either version 2, or (at your option) any later version.
178 This program is distributed in the hope that it will be useful, but WITHOUT
179 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
180 FOR A PARTICULAR PURPOSE.
181 See the GNU General Public License for more details.
182 You should have received a copy of the GNU General Public License along
183 with this program; if not, write to the Free Software Foundation, 59 Temple
184 Place - Suite 330, Boston, MA 02111-1307, USA.
185 In other words, you are welcome to use, share and improve this program.
186 You are forbidden to forbid anyone else to use, share and improve what
188 Help stamp out software-hoarding!
191 Typographic conventions
194 Throughout this manual, we will use the following convention.
195 Commands you have to type in are printed in
203 Code samples are printed in
208 Interesting items and new terms are printed in
213 Compatibility with previous versions
216 This version has numerous bug fixes compared with the previous version.
217 But we also introduced some incompatibilities with older versions.
218 Not just for the fun of it, but to make the compiler more stable, efficient
225 short is now equivalent to int (16 bits), it used to be equivalent to char
226 (8 bits) which is not ANSI compliant
229 the default directory for gcc-builds where include, library and documention
230 files are stored is now in /usr/local/share
233 char type parameters to vararg functions are casted to int unless explicitly
250 will push a as an int and as a char resp.
253 option ---regextend has been removed
256 option ---noregparms has been removed
259 option ---stack-after-data has been removed
264 <pending: more incompatibilities?>
270 What do you need before you start installation of SDCC? A computer, and
272 The preferred method of installation is to compile SDCC from source using
274 For Windows some pre-compiled binary distributions are available for your
276 You should have some experience with command line tools and compiler use.
282 The SDCC home page at
283 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
287 is a great place to find distribution sets.
288 You can also find links to the user mailing lists that offer help or discuss
289 SDCC with other SDCC users.
290 Web links to other SDCC related sites can also be found here.
291 This document can be found in the DOC directory of the source package as
293 Some of the other tools (simulator and assembler) included with SDCC contain
294 their own documentation and can be found in the source distribution.
295 If you want the latest unreleased software, the complete source package
296 is available directly by anonymous CVS on cvs.sdcc.sourceforge.net.
299 Wishes for the future
302 There are (and always will be) some things that could be done.
303 Here are some I can think of:
310 char KernelFunction3(char p) at 0x340;
316 If you can think of some more, please send them to the list.
322 <pending: And then of course a proper index-table
323 \begin_inset LatexCommand \index{index}
336 The install paths, search paths and other options are defined when running
338 The defaults can be overriden by:
340 \labelwidthstring 00.00.0000
342 ---prefix see tabel below
344 \labelwidthstring 00.00.0000
346 ---exec_prefix see tabel below
348 \labelwidthstring 00.00.0000
350 ---bindir see tabel below
352 \labelwidthstring 00.00.0000
354 ---datadir see tabel below
356 \labelwidthstring 00.00.0000
358 docdir environment variable, see tabel below
360 \labelwidthstring 00.00.0000
362 include_dir_suffix environment variable, see tabel below
364 \labelwidthstring 00.00.0000
366 lib_dir_suffix environment variable, see tabel below
368 \labelwidthstring 00.00.0000
370 sdccconf_h_dir_separator environment variable, either / or
375 This character will only be used in sdccconf.h; don't forget it's a C-header,
376 therefore a double-backslash is needed there.
378 \labelwidthstring 00.00.0000
380 ---disable-mcs51-port Excludes the Intel mcs51 port
382 \labelwidthstring 00.00.0000
384 ---disable-gbz80-port Excludes the Gameboy gbz80 port
386 \labelwidthstring 00.00.0000
388 ---disable-z80-port Excludes the z80 port
390 \labelwidthstring 00.00.0000
392 ---disable-avr-port Excludes the AVR port
394 \labelwidthstring 00.00.0000
396 ---disable-ds390-port Excludes the DS390 port
398 \labelwidthstring 00.00.0000
400 ---disable-pic-port Excludes the PIC port
402 \labelwidthstring 00.00.0000
404 ---disable-xa51-port Excludes the XA51 port
406 \labelwidthstring 00.00.0000
408 ---disable-ucsim Disables configuring and building of ucsim
410 \labelwidthstring 00.00.0000
412 ---disable-device-lib-build Disables automatically building device libraries
414 \labelwidthstring 00.00.0000
416 ---disable-packihx Disables building packihx
418 \labelwidthstring 00.00.0000
420 ---enable-libgc Use the Bohem memory allocator.
421 Lower runtime footprint.
424 Furthermore the environment variables CC, CFLAGS, ...
425 the tools and their arguments can be influenced.
426 Please see `configure ---help` and the man/info pages of `configure` for
431 The names of the standard libraries STD_LIB, STD_INT_LIB, STD_LONG_LIB,
432 STD_FP_LIB, STD_DS390_LIB, STD_XA51_LIB and the environment variables SDCC_DIR_
433 NAME, SDCC_INCLUDE_NAME, SDCC_LIB_NAME are defined by `configure` too.
434 At the moment it's not possible to change the default settings (it was
435 simply never required.
439 These configure options are compiled into the binaries, and can only be
440 changed by rerunning 'configure' and recompiling SDCC.
441 The configure options are written in
445 to distinguish them from run time environment variables (see section search
451 \begin_inset Quotes sld
455 \begin_inset Quotes srd
458 are used by the SDCC team to build the official Win32 binaries.
459 The SDCC team uses Mingw32 to build the official Windows binaries, because
466 a gcc compiler and last but not least
469 the binaries can be built by cross compiling on Sourceforge's compile farm.
472 See the examples, how to pass the Win32 settings to 'configure'.
473 The other Win32 builds using Borland, VC or whatever don't use 'configure',
474 but a header file sdcc_vc_in.h is the same as sdccconf.h built by 'configure'
485 <lyxtabular version="3" rows="8" columns="3">
487 <column alignment="left" valignment="top" leftline="true" width="0in">
488 <column alignment="left" valignment="top" leftline="true" width="0in">
489 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
490 <row topline="true" bottomline="true">
491 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
499 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
507 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
517 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
527 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
535 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
547 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
557 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
567 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
579 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
589 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
601 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
617 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
627 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
639 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
651 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
661 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
673 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
689 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
699 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
707 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
716 <row topline="true" bottomline="true">
717 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
727 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
735 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
754 'configure' also computes relative paths.
755 This is needed for full relocatability of a binary package and to complete
756 search paths (see section search paths below):
762 <lyxtabular version="3" rows="4" columns="3">
764 <column alignment="left" valignment="top" leftline="true" width="0in">
765 <column alignment="left" valignment="top" leftline="true" width="0in">
766 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
767 <row topline="true" bottomline="true">
768 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
776 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
784 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
793 <row topline="true" bottomline="true">
794 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
804 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
812 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
823 <row bottomline="true">
824 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
834 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
842 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
851 <row bottomline="true">
852 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
862 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
870 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
892 ./configure ---prefix=
893 \begin_inset Quotes srd
897 \begin_inset Quotes srd
901 \begin_inset Quotes srd
905 \begin_inset Quotes srd
911 ./configure ---disable-avr-port ---disable-xa51-port
914 To crosscompile on linux for Mingw32 (see also 'sdcc/support/scripts/sdcc_mingw3
924 \begin_inset Quotes srd
928 \begin_inset Quotes srd
932 \begin_inset Quotes srd
936 \begin_inset Quotes srd
945 \begin_inset Quotes srd
948 i586-mingw32msvc-ranlib
949 \begin_inset Quotes srd
958 \begin_inset Quotes srd
961 i586-mingw32msvc-strip
962 \begin_inset Quotes srd
971 \begin_inset Quotes srd
975 \begin_inset Quotes srd
984 \begin_inset Quotes srd
988 \begin_inset Quotes srd
997 \begin_inset Quotes srd
1001 \begin_inset Quotes srd
1010 \begin_inset Quotes srd
1014 \begin_inset Quotes srd
1023 \begin_inset Quotes srd
1027 \begin_inset Quotes srd
1035 sdccconf_h_dir_separator=
1036 \begin_inset Quotes srd
1048 \begin_inset Quotes srd
1056 ---disable-device-lib-build
1066 ---host=i586-mingw32msvc ---build=unknown-unknown-linux-gnu
1070 \begin_inset Quotes sld
1074 \begin_inset Quotes srd
1077 compile on Cygwin for Mingw32(see also sdcc/support/scripts/sdcc_cygwin_mingw32)
1087 \begin_inset Quotes srd
1091 \begin_inset Quotes srd
1100 \begin_inset Quotes srd
1104 \begin_inset Quotes srd
1113 \begin_inset Quotes srd
1117 \begin_inset Quotes srd
1126 \begin_inset Quotes srd
1130 \begin_inset Quotes srd
1139 \begin_inset Quotes srd
1143 \begin_inset Quotes srd
1152 \begin_inset Quotes srd
1156 \begin_inset Quotes srd
1165 \begin_inset Quotes srd
1169 \begin_inset Quotes srd
1177 sdccconf_h_dir_separator=
1178 \begin_inset Quotes srd
1190 \begin_inset Quotes srd
1201 'configure' is quite slow on Cygwin (at least on windows before Win2000/XP).
1202 The option '--C' turns on caching, which gives a little bit extra speed.
1203 However if options are changed, it can be necessary to delete the config.cache
1211 Binary files (preprocessor, assembler and linker)
1215 \begin_inset Tabular
1216 <lyxtabular version="3" rows="2" columns="3">
1218 <column alignment="left" valignment="top" leftline="true" width="0in">
1219 <column alignment="left" valignment="top" leftline="true" width="0in">
1220 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
1221 <row topline="true" bottomline="true">
1222 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1230 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1238 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1247 <row topline="true" bottomline="true">
1248 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1258 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1266 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1292 \begin_inset Tabular
1293 <lyxtabular version="3" rows="2" columns="3">
1295 <column alignment="block" valignment="top" leftline="true" width="1.6in">
1296 <column alignment="left" valignment="top" leftline="true" width="0in">
1297 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0in">
1298 <row topline="true" bottomline="true">
1299 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1307 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1315 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1324 <row topline="true" bottomline="true">
1325 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1337 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1342 /usr/local/share/sdcc/include
1345 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1371 is auto-appended by the compiler, e.g.
1372 small, large, z80, ds390 etc.)
1376 \begin_inset Tabular
1377 <lyxtabular version="3" rows="2" columns="3">
1379 <column alignment="left" valignment="top" leftline="true" width="0in">
1380 <column alignment="left" valignment="top" leftline="true" width="0in">
1381 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
1382 <row topline="true" bottomline="true">
1383 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1391 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1399 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1408 <row topline="true" bottomline="true">
1409 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1416 $DATADIR/$LIB_DIR_SUFFIX
1419 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1424 /usr/local/share/sdcc/lib
1427 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1453 \begin_inset Tabular
1454 <lyxtabular version="3" rows="2" columns="3">
1456 <column alignment="left" valignment="top" leftline="true" width="0in">
1457 <column alignment="left" valignment="top" leftline="true" width="0in">
1458 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
1459 <row topline="true" bottomline="true">
1460 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1468 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1476 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1485 <row topline="true" bottomline="true">
1486 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1496 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1501 /usr/local/share/sdcc/doc
1504 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1525 The install paths can still be changed during `make install` with e.g.:
1528 make install prefix=$(HOME)/local/sdcc
1531 Of course this doesn't change the search paths compiled into the binaries.
1537 Some search paths or parts of them are determined by configure variables
1542 , see section above).
1543 Further search paths are determined by environment variables during runtime.
1546 The paths searched when running the compiler are as follows (the first catch
1552 Binary files (preprocessor, assembler and linker)
1555 \begin_inset Tabular
1556 <lyxtabular version="3" rows="4" columns="3">
1558 <column alignment="left" valignment="top" leftline="true" width="0in">
1559 <column alignment="left" valignment="top" leftline="true" width="0in">
1560 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
1561 <row topline="true" bottomline="true">
1562 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1570 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1578 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1587 <row topline="true">
1588 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1598 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1606 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1617 <row topline="true">
1618 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1623 Path of argv[0] (if available)
1626 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1634 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1643 <row topline="true" bottomline="true">
1644 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1652 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1660 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1681 \begin_inset Tabular
1682 <lyxtabular version="3" rows="6" columns="3">
1684 <column alignment="block" valignment="top" leftline="true" width="1.5in">
1685 <column alignment="block" valignment="top" leftline="true" width="1.5in">
1686 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
1687 <row topline="true" bottomline="true">
1688 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1696 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1704 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1713 <row topline="true">
1714 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1722 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1730 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1739 <row topline="true">
1740 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1748 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1756 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1765 <row topline="true">
1766 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1780 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1792 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1803 <row topline="true">
1804 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1822 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1872 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1885 <row topline="true" bottomline="true">
1886 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1902 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1907 /usr/local/share/sdcc/
1912 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1929 The option ---nostdinc disables the last two search paths.
1936 With the exception of
1937 \begin_inset Quotes sld
1941 \begin_inset Quotes srd
1948 is auto-appended by the compiler (e.g.
1949 small, large, z80, ds390 etc.).
1953 \begin_inset Tabular
1954 <lyxtabular version="3" rows="6" columns="3">
1956 <column alignment="block" valignment="top" leftline="true" width="1.7in">
1957 <column alignment="left" valignment="top" leftline="true" width="1.2in">
1958 <column alignment="block" valignment="top" leftline="true" rightline="true" width="1.2in">
1959 <row topline="true" bottomline="true">
1960 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1968 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1976 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1985 <row topline="true">
1986 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
1994 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2002 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2011 <row topline="true">
2012 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2024 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2036 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2051 <row topline="true">
2052 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2063 $LIB_DIR_SUFFIX/<model>
2066 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2080 <cell alignment="left" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2097 <row topline="true">
2098 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2113 $LIB_DIR_SUFFIX/<model>
2116 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2169 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2225 <row topline="true" bottomline="true">
2226 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2235 $LIB_DIR_SUFFIX/<model>
2238 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2243 /usr/local/share/sdcc/
2250 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2266 Don't delete any of the stray spaces in the table above without checking
2267 the HTML output (last line)!
2273 The option ---nostdlib disables the last two search paths.
2277 \layout Subsubsection
2279 Building SDCC on Linux
2284 Download the source package
2286 either from the SDCC CVS repository or from the
2287 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
2293 , it will be named something like sdcc
2306 Bring up a command line terminal, such as xterm.
2311 Unpack the file using a command like:
2314 "tar -xzf sdcc.src.tar.gz
2319 , this will create a sub-directory called sdcc with all of the sources.
2322 Change directory into the main SDCC directory, for example type:
2339 This configures the package for compilation on your system.
2355 All of the source packages will compile, this can take a while.
2371 This copies the binary executables, the include files, the libraries and
2372 the documentation to the install directories.
2373 \layout Subsubsection
2375 Building SDCC on OSX 2.x
2378 Follow the instruction for Linux.
2382 On OSX 2.x it was reported, that the default gcc (version 3.1 20020420 (prerelease
2383 )) fails to compile SDCC.
2384 Fortunately there's also gcc 2.9.x installed, which works fine.
2385 This compiler can be selected by running 'configure' with:
2388 ./configure CC=gcc2 CXX=g++2
2389 \layout Subsubsection
2391 Crosscompiling SDCC on Linux for Windows
2394 With the Mingw32 gcc crosscompiler it's easy to compile SDCC for Win32.
2395 See section 'Configure Options'.
2396 \layout Subsubsection
2398 Building SDCC on Windows
2401 With the exception of Cygwin the SDCC binaries uCsim and sdcdb can't be
2403 They use Unix-sockets, which are not available on Win32.
2404 \layout Subsubsection
2406 Windows Install Using a Binary Package
2409 Download the binary package and unpack it using your favorite unpacking
2410 tool (gunzip, WinZip, etc).
2411 This should unpack to a group of sub-directories.
2412 An example directory structure after unpacking the mingw32 package is:
2417 bin for the executables, c:
2425 lib for the include and libraries.
2428 Adjust your environment variable PATH to include the location of the bin
2429 directory or start sdcc using the full path.
2430 \layout Subsubsection
2432 Building SDCC using Cygwin and Mingw32
2435 For building and installing a Cygwin executable follow the instructions
2441 \begin_inset Quotes sld
2445 \begin_inset Quotes srd
2448 Win32-binary can be built, which will not need the Cygwin-DLL.
2449 For the necessary 'configure' options see section 'configure options' or
2450 the script 'sdcc/support/scripts/sdcc_cygwinmingw32'.
2454 In order to install Cygwin on Windows download setup.exe from
2455 \begin_inset LatexCommand \url[www.cygwin.com]{http://www.cygwin.com/}
2461 \begin_inset Quotes sld
2464 default text file type
2465 \begin_inset Quotes srd
2469 \begin_inset Quotes sld
2473 \begin_inset Quotes srd
2476 and download/install at least the following packages.
2477 Some packages are selected by default, others will be automatically selected
2478 because of dependencies with the manually selected packages.
2479 Never deselect these packages!
2488 gcc ; version 3.x is fine, no need to use the old 2.9x
2491 binutils ; selected with gcc
2497 rxvt ; a nice console, which makes life much easier under windoze (see below)
2500 man ; not really needed for building SDCC, but you'll miss it sooner or
2504 less ; not really needed for building SDCC, but you'll miss it sooner or
2508 cvs ; only if you use CVS access
2511 If you want to develop something you'll need:
2514 python ; for the regression tests
2517 gdb ; the gnu debugger, together with the nice GUI
2518 \begin_inset Quotes sld
2522 \begin_inset Quotes srd
2528 openssh ; to access the CF or commit changes
2531 autoconf and autoconf-devel ; if you want to fight with 'configure', don't
2532 use autoconf-stable!
2535 rxvt is a nice console with history.
2536 Replace in your cygwin.bat the line
2545 rxvt -sl 1000 -fn "Lucida Console-12" -sr -cr red
2548 -bg black -fg white -geometry 100x65 -e bash --login
2551 Text selected with the mouse is automatically copied to the clipboard, pasting
2552 works with shift-insert.
2556 The other good tip is to make sure you have no //c/-style paths anywhere,
2557 use /cygdrive/c/ instead.
2558 Using // invokes a network lookup which is very slow.
2560 \begin_inset Quotes sld
2564 \begin_inset Quotes srd
2567 is too long, you can change it with e.g.
2573 SDCC sources use the unix line ending LF.
2574 Life is much easier, if you store the source tree on a drive, which is
2575 mount in binary mode.
2576 And use an editor which can handle LF-only line endings.
2577 Make sure not to commit files with windows line endings.
2578 \layout Subsubsection
2580 Windows Install Using Microsoft Visual C++ 6.0/NET
2585 Download the source package
2587 either from the SDCC CVS repository or from the
2588 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
2594 , it will be named something like sdcc
2601 SDCC is distributed with all the projects, workspaces, and files you need
2602 to build it using Visual C++ 6.0/NET.
2603 The workspace name is 'sdcc.dsw'.
2604 Please note that as it is now, all the executables are created in a folder
2608 Once built you need to copy the executables from sdcc
2612 bin before runnng SDCC.
2617 In order to build SDCC with Visual C++ 6.0/NET you need win32 executables
2618 of bison.exe, flex.exe, and gawk.exe.
2619 One good place to get them is
2620 \begin_inset LatexCommand \url[here]{http://unxutils.sourceforge.net}
2628 Download the file UnxUtils.zip.
2629 Now you have to install the utilities and setup Visual C++ so it can locate
2630 the required programs.
2631 Here there are two alternatives (choose one!):
2638 a) Extract UnxUtils.zip to your C:
2640 hard disk PRESERVING the original paths, otherwise bison won't work.
2641 (If you are using WinZip make certain that 'Use folder names' is selected)
2645 b) In the Visual C++ IDE click Tools, Options, select the Directory tab,
2646 in 'Show directories for:' select 'Executable files', and in the directories
2647 window add a new path: 'C:
2657 (As a side effect, you get a bunch of Unix utilities that could be useful,
2658 such as diff and patch.)
2665 This one avoids extracting a bunch of files you may not use, but requires
2670 a) Create a directory were to put the tools needed, or use a directory already
2678 b) Extract 'bison.exe', 'bison.hairy', 'bison.simple', 'flex.exe', and gawk.exe
2679 to such directory WITHOUT preserving the original paths.
2680 (If you are using WinZip make certain that 'Use folder names' is not selected)
2684 c) Rename bison.exe to '_bison.exe'.
2688 d) Create a batch file 'bison.bat' in 'C:
2692 ' and add these lines:
2712 _bison %1 %2 %3 %4 %5 %6 %7 %8 %9
2716 Steps 'c' and 'd' are needed because bison requires by default that the
2717 files 'bison.simple' and 'bison.hairy' reside in some weird Unix directory,
2718 '/usr/local/share/' I think.
2719 So it is necessary to tell bison where those files are located if they
2720 are not in such directory.
2721 That is the function of the environment variables BISON_SIMPLE and BISON_HAIRY.
2725 e) In the Visual C++ IDE click Tools, Options, select the Directory tab,
2726 in 'Show directories for:' select 'Executable files', and in the directories
2727 window add a new path: 'c:
2730 Note that you can use any other path instead of 'c:
2732 util', even the path where the Visual C++ tools are, probably: 'C:
2736 Microsoft Visual Studio
2741 So you don't have to execute step 'e' :)
2745 Open 'sdcc.dsw' in Visual Studio, click 'build all', when it finishes copy
2746 the executables from sdcc
2750 bin, and you can compile using sdcc.
2751 \layout Subsubsection
2753 Windows Install Using Borland
2756 From the sdcc directory, run the command "make -f Makefile.bcc".
2757 This should regenerate all the .exe files in the bin directory except for
2758 sdcdb.exe (which currently doesn't build under Borland C++).
2761 If you modify any source files and need to rebuild, be aware that the dependanci
2762 es may not be correctly calculated.
2763 The safest option is to delete all .obj files and run the build again.
2764 From a Cygwin BASH prompt, this can easily be done with the commmand:
2774 ( -name '*.obj' -o -name '*.lib' -o -name '*.rul'
2776 ) -print -exec rm {}
2785 or on Windows NT/2000/XP from the command prompt with the commmand:
2792 del /s *.obj *.lib *.rul
2795 from the sdcc directory.
2798 Building the Documentation
2805 Testing out the SDCC Compiler
2808 The first thing you should do after installing your SDCC compiler is to
2816 at the prompt, and the program should run and tell you the version.
2817 If it doesn't run, or gives a message about not finding sdcc program, then
2818 you need to check over your installation.
2819 Make sure that the sdcc bin directory is in your executable search path
2820 defined by the PATH environment setting (see the Trouble-shooting section
2822 Make sure that the sdcc program is in the bin folder, if not perhaps something
2823 did not install correctly.
2831 is commonly installed as described in section
2832 \begin_inset Quotes sld
2835 Install and search paths
2836 \begin_inset Quotes srd
2845 Make sure the compiler works on a very simple example.
2846 Type in the following test.c program using your favorite
2881 Compile this using the following command:
2890 If all goes well, the compiler will generate a test.asm and test.rel file.
2891 Congratulations, you've just compiled your first program with SDCC.
2892 We used the -c option to tell SDCC not to link the generated code, just
2893 to keep things simple for this step.
2901 The next step is to try it with the linker.
2911 If all goes well the compiler will link with the libraries and produce
2912 a test.ihx output file.
2917 (no test.ihx, and the linker generates warnings), then the problem is most
2918 likely that sdcc cannot find the
2922 usr/local/share/sdcc/lib directory
2926 (see the Install trouble-shooting section for suggestions).
2934 The final test is to ensure sdcc can use the
2938 header files and libraries.
2939 Edit test.c and change it to the following:
2959 strcpy(str1, "testing");
2968 Compile this by typing
2975 This should generate a test.ihx output file, and it should give no warnings
2976 such as not finding the string.h file.
2977 If it cannot find the string.h file, then the problem is that sdcc cannot
2978 find the /usr/local/share/sdcc/include directory
2982 (see the Install trouble-shooting section for suggestions).
2985 Install Trouble-shooting
2986 \layout Subsubsection
2988 SDCC does not build correctly.
2991 A thing to try is starting from scratch by unpacking the .tgz source package
2992 again in an empty directory.
3000 ./configure 2>&1 | tee configure.log
3014 make 2>&1 | tee make.log
3021 If anything goes wrong, you can review the log files to locate the problem.
3022 Or a relevant part of this can be attached to an email that could be helpful
3023 when requesting help from the mailing list.
3024 \layout Subsubsection
3027 \begin_inset Quotes sld
3031 \begin_inset Quotes srd
3038 \begin_inset Quotes sld
3042 \begin_inset Quotes srd
3045 command is a script that analyzes your system and performs some configuration
3046 to ensure the source package compiles on your system.
3047 It will take a few minutes to run, and will compile a few tests to determine
3048 what compiler features are installed.
3049 \layout Subsubsection
3052 \begin_inset Quotes sld
3056 \begin_inset Quotes srd
3062 This runs the GNU make tool, which automatically compiles all the source
3063 packages into the final installed binary executables.
3064 \layout Subsubsection
3067 \begin_inset Quotes sld
3071 \begin_inset Quotes erd
3077 This will install the compiler, other executables libraries and include
3078 files in to the appropriate directories.
3080 \begin_inset Quotes sld
3083 Install and Search PATHS
3084 \begin_inset Quotes srd
3089 On most systems you will need super-user privilages to do this.
3095 SDCC is not just a compiler, but a collection of tools by various developers.
3096 These include linkers, assemblers, simulators and other components.
3097 Here is a summary of some of the components.
3098 Note that the included simulator and assembler have separate documentation
3099 which you can find in the source package in their respective directories.
3100 As SDCC grows to include support for other processors, other packages from
3101 various developers are included and may have their own sets of documentation.
3105 You might want to look at the files which are installed in <installdir>.
3106 At the time of this writing, we find the following programs for gcc-builds:
3110 In <installdir>/bin:
3113 sdcc - The compiler.
3116 sdcpp - The C preprocessor.
3119 asx8051 - The assembler for 8051 type processors.
3126 as-gbz80 - The Z80 and GameBoy Z80 assemblers.
3129 aslink -The linker for 8051 type processors.
3136 link-gbz80 - The Z80 and GameBoy Z80 linkers.
3139 s51 - The ucSim 8051 simulator.
3142 sdcdb - The source debugger.
3145 packihx - A tool to pack (compress) Intel hex files.
3148 In <installdir>/share/sdcc/include
3154 In <installdir>/share/sdcc/lib
3157 the subdirs src and small, large, z80, gbz80 and ds390 with the precompiled
3161 In <installdir>/share/sdcc/doc
3167 As development for other processors proceeds, this list will expand to include
3168 executables to support processors like AVR, PIC, etc.
3169 \layout Subsubsection
3174 This is the actual compiler, it in turn uses the c-preprocessor and invokes
3175 the assembler and linkage editor.
3176 \layout Subsubsection
3178 sdcpp - The C-Preprocessor
3181 The preprocessor is a modified version of the GNU preprocessor.
3182 The C preprocessor is used to pull in #include sources, process #ifdef
3183 statements, #defines and so on.
3184 \layout Subsubsection
3186 asx8051, as-z80, as-gbz80, aslink, link-z80, link-gbz80 - The Assemblers
3190 This is retargettable assembler & linkage editor, it was developed by Alan
3192 John Hartman created the version for 8051, and I (Sandeep) have made some
3193 enhancements and bug fixes for it to work properly with the SDCC.
3194 \layout Subsubsection
3199 S51 is a freeware, opensource simulator developed by Daniel Drotos (
3200 \begin_inset LatexCommand \url{mailto:drdani@mazsola.iit.uni-miskolc.hu}
3205 The simulator is built as part of the build process.
3206 For more information visit Daniel's website at:
3207 \begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
3212 It currently support the core mcs51, the Dallas DS80C390 and the Philips
3214 \layout Subsubsection
3216 sdcdb - Source Level Debugger
3222 <todo: is this thing still alive?>
3229 Sdcdb is the companion source level debugger.
3230 The current version of the debugger uses Daniel's Simulator S51, but can
3231 be easily changed to use other simulators.
3238 \layout Subsubsection
3240 Single Source File Projects
3243 For single source file 8051 projects the process is very simple.
3244 Compile your programs with the following command
3247 "sdcc sourcefile.c".
3251 This will compile, assemble and link your source file.
3252 Output files are as follows
3256 sourcefile.asm - Assembler source file created by the compiler
3258 sourcefile.lst - Assembler listing file created by the Assembler
3260 sourcefile.rst - Assembler listing file updated with linkedit information,
3261 created by linkage editor
3263 sourcefile.sym - symbol listing for the sourcefile, created by the assembler
3265 sourcefile.rel - Object file created by the assembler, input to Linkage editor
3267 sourcefile.map - The memory map for the load module, created by the Linker
3269 sourcefile.ihx - The load module in Intel hex format (you can select the
3270 Motorola S19 format with ---out-fmt-s19)
3272 sourcefile.cdb - An optional file (with ---debug) containing debug information
3274 sourcefile.dump* - Dump file to debug the compiler it self (with ---dumpall)
3276 \begin_inset Quotes sld
3279 Anatomy of the compiler
3280 \begin_inset Quotes srd
3284 \layout Subsubsection
3286 Projects with Multiple Source Files
3289 SDCC can compile only ONE file at a time.
3290 Let us for example assume that you have a project containing the following
3295 foo1.c (contains some functions)
3297 foo2.c (contains some more functions)
3299 foomain.c (contains more functions and the function main)
3307 The first two files will need to be compiled separately with the commands:
3339 Then compile the source file containing the
3343 function and link the files together with the following command:
3351 foomain.c\SpecialChar ~
3352 foo1.rel\SpecialChar ~
3364 can be separately compiled as well:
3375 sdcc foomain.rel foo1.rel foo2.rel
3382 The file containing the
3397 file specified in the command line, since the linkage editor processes
3398 file in the order they are presented to it.
3399 \layout Subsubsection
3401 Projects with Additional Libraries
3404 Some reusable routines may be compiled into a library, see the documentation
3405 for the assembler and linkage editor (which are in <installdir>/share/sdcc/doc)
3411 Libraries created in this manner can be included in the command line.
3412 Make sure you include the -L <library-path> option to tell the linker where
3413 to look for these files if they are not in the current directory.
3414 Here is an example, assuming you have the source file
3426 (if that is not the same as your current project):
3433 sdcc foomain.c foolib.lib -L mylib
3444 must be an absolute path name.
3448 The most efficient way to use libraries is to keep seperate modules in seperate
3450 The lib file now should name all the modules.rel files.
3451 For an example see the standard library file
3455 in the directory <installdir>/share/lib/small.
3458 Command Line Options
3459 \layout Subsubsection
3461 Processor Selection Options
3463 \labelwidthstring 00.00.0000
3469 Generate code for the MCS51 (8051) family of processors.
3470 This is the default processor target.
3472 \labelwidthstring 00.00.0000
3478 Generate code for the DS80C390 processor.
3480 \labelwidthstring 00.00.0000
3486 Generate code for the Z80 family of processors.
3488 \labelwidthstring 00.00.0000
3494 Generate code for the GameBoy Z80 processor.
3496 \labelwidthstring 00.00.0000
3502 Generate code for the Atmel AVR processor (In development, not complete).
3504 \labelwidthstring 00.00.0000
3510 Generate code for the PIC 14-bit processors (In development, not complete).
3512 \labelwidthstring 00.00.0000
3518 Generate code for the Toshiba TLCS-900H processor (In development, not
3521 \labelwidthstring 00.00.0000
3527 Generate code for the Philips XA51 processor (In development, not complete).
3528 \layout Subsubsection
3530 Preprocessor Options
3532 \labelwidthstring 00.00.0000
3538 The additional location where the pre processor will look for <..h> or
3539 \begin_inset Quotes eld
3543 \begin_inset Quotes erd
3548 \labelwidthstring 00.00.0000
3554 Command line definition of macros.
3555 Passed to the pre processor.
3557 \labelwidthstring 00.00.0000
3563 Tell the preprocessor to output a rule suitable for make describing the
3564 dependencies of each object file.
3565 For each source file, the preprocessor outputs one make-rule whose target
3566 is the object file name for that source file and whose dependencies are
3567 all the files `#include'd in it.
3568 This rule may be a single line or may be continued with `
3570 '-newline if it is long.
3571 The list of rules is printed on standard output instead of the preprocessed
3575 \labelwidthstring 00.00.0000
3581 Tell the preprocessor not to discard comments.
3582 Used with the `-E' option.
3584 \labelwidthstring 00.00.0000
3595 Like `-M' but the output mentions only the user header files included with
3597 \begin_inset Quotes eld
3601 System header files included with `#include <file>' are omitted.
3603 \labelwidthstring 00.00.0000
3609 Assert the answer answer for question, in case it is tested with a preprocessor
3610 conditional such as `#if #question(answer)'.
3611 `-A-' disables the standard assertions that normally describe the target
3614 \labelwidthstring 00.00.0000
3620 (answer) Assert the answer answer for question, in case it is tested with
3621 a preprocessor conditional such as `#if #question(answer)'.
3622 `-A-' disables the standard assertions that normally describe the target
3625 \labelwidthstring 00.00.0000
3631 Undefine macro macro.
3632 `-U' options are evaluated after all `-D' options, but before any `-include'
3633 and `-imacros' options.
3635 \labelwidthstring 00.00.0000
3641 Tell the preprocessor to output only a list of the macro definitions that
3642 are in effect at the end of preprocessing.
3643 Used with the `-E' option.
3645 \labelwidthstring 00.00.0000
3651 Tell the preprocessor to pass all macro definitions into the output, in
3652 their proper sequence in the rest of the output.
3654 \labelwidthstring 00.00.0000
3665 Like `-dD' except that the macro arguments and contents are omitted.
3666 Only `#define name' is included in the output.
3667 \layout Subsubsection
3671 \labelwidthstring 00.00.0000
3681 <absolute path to additional libraries> This option is passed to the linkage
3682 editor's additional libraries search path.
3683 The path name must be absolute.
3684 Additional library files may be specified in the command line.
3685 See section Compiling programs for more details.
3687 \labelwidthstring 00.00.0000
3693 <Value> The start location of the external ram, default value is 0.
3694 The value entered can be in Hexadecimal or Decimal format, e.g.: ---xram-loc
3695 0x8000 or ---xram-loc 32768.
3697 \labelwidthstring 00.00.0000
3703 <Value> The start location of the code segment, default value 0.
3704 Note when this option is used the interrupt vector table is also relocated
3705 to the given address.
3706 The value entered can be in Hexadecimal or Decimal format, e.g.: ---code-loc
3707 0x8000 or ---code-loc 32768.
3709 \labelwidthstring 00.00.0000
3715 <Value> By default the stack is placed after the data segment.
3716 Using this option the stack can be placed anywhere in the internal memory
3718 The value entered can be in Hexadecimal or Decimal format, e.g.
3719 ---stack-loc 0x20 or ---stack-loc 32.
3720 Since the sp register is incremented before a push or call, the initial
3721 sp will be set to one byte prior the provided value.
3722 The provided value should not overlap any other memory areas such as used
3723 register banks or the data segment and with enough space for the current
3726 \labelwidthstring 00.00.0000
3732 <Value> The start location of the internal ram data segment.
3733 The value entered can be in Hexadecimal or Decimal format, eg.
3734 ---data-loc 0x20 or ---data-loc 32.
3735 (By default, the start location of the internal ram data segment is set
3736 as low as possible in memory, taking into account the used register banks
3737 and the bit segment at address 0x20.
3738 For example if register banks 0 and 1 are used without bit variables, the
3739 data segment will be set, if ---data-loc is not used, to location 0x10.)
3741 \labelwidthstring 00.00.0000
3747 <Value> The start location of the indirectly addressable internal ram, default
3749 The value entered can be in Hexadecimal or Decimal format, eg.
3750 ---idata-loc 0x88 or ---idata-loc 136.
3752 \labelwidthstring 00.00.0000
3761 The linker output (final object code) is in Intel Hex format.
3762 (This is the default option).
3764 \labelwidthstring 00.00.0000
3773 The linker output (final object code) is in Motorola S19 format.
3774 \layout Subsubsection
3778 \labelwidthstring 00.00.0000
3784 Generate code for Large model programs see section Memory Models for more
3786 If this option is used all source files in the project should be compiled
3788 In addition the standard library routines are compiled with small model,
3789 they will need to be recompiled.
3791 \labelwidthstring 00.00.0000
3802 Generate code for Small Model programs see section Memory Models for more
3804 This is the default model.
3805 \layout Subsubsection
3809 \labelwidthstring 00.00.0000
3820 Generate 24-bit flat mode code.
3821 This is the one and only that the ds390 code generator supports right now
3822 and is default when using
3827 See section Memory Models for more details.
3829 \labelwidthstring 00.00.0000
3835 Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
3836 This is the one and only that the ds390 code generator supports right now
3837 and is default when using
3842 In this mode, the stack is located in the lower 1K of the internal RAM,
3843 which is mapped to 0x400000.
3844 Note that the support is incomplete, since it still uses a single byte
3845 as the stack pointer.
3846 This means that only the lower 256 bytes of the potential 1K stack space
3847 will actually be used.
3848 However, this does allow you to reclaim the precious 256 bytes of low RAM
3849 for use for the DATA and IDATA segments.
3850 The compiler will not generate any code to put the processor into 10 bit
3852 It is important to ensure that the processor is in this mode before calling
3853 any re-entrant functions compiled with this option.
3854 In principle, this should work with the
3858 option, but that has not been tested.
3859 It is incompatible with the
3864 It also only makes sense if the processor is in 24 bit contiguous addressing
3867 ---model-flat24 option
3870 \layout Subsubsection
3872 Optimization Options
3874 \labelwidthstring 00.00.0000
3880 Will not do global subexpression elimination, this option may be used when
3881 the compiler creates undesirably large stack/data spaces to store compiler
3883 A warning message will be generated when this happens and the compiler
3884 will indicate the number of extra bytes it allocated.
3885 It recommended that this option NOT be used, #pragma\SpecialChar ~
3887 to turn off global subexpression elimination for a given function only.
3889 \labelwidthstring 00.00.0000
3895 Will not do loop invariant optimizations, this may be turned off for reasons
3896 explained for the previous option.
3897 For more details of loop optimizations performed see section Loop Invariants.It
3898 recommended that this option NOT be used, #pragma\SpecialChar ~
3899 NOINVARIANT can be used
3900 to turn off invariant optimizations for a given function only.
3902 \labelwidthstring 00.00.0000
3908 Will not do loop induction optimizations, see section strength reduction
3909 for more details.It is recommended that this option is NOT used, #pragma\SpecialChar ~
3911 ION can be used to turn off induction optimizations for a given function
3914 \labelwidthstring 00.00.0000
3925 Will not generate boundary condition check when switch statements are implement
3926 ed using jump-tables.
3927 See section Switch Statements for more details.
3928 It is recommended that this option is NOT used, #pragma\SpecialChar ~
3930 used to turn off boundary checking for jump tables for a given function
3933 \labelwidthstring 00.00.0000
3942 Will not do loop reversal optimization.
3944 \labelwidthstring 00.00.0000
3950 Will not optimize labels (makes the dumpfiles more readable).
3952 \labelwidthstring 00.00.0000
3958 Will not memcpy initialized data in far space from code space.
3959 This saves a few bytes in code space if you don't have initialized data.
3960 \layout Subsubsection
3964 \labelwidthstring 00.00.0000
3971 will compile and assemble the source, but will not call the linkage editor.
3973 \labelwidthstring 00.00.0000
3979 reads the preprocessed source from standard input and compiles it.
3980 The file name for the assembler output must be specified using the -o option.
3982 \labelwidthstring 00.00.0000
3988 Run only the C preprocessor.
3989 Preprocess all the C source files specified and output the results to standard
3992 \labelwidthstring 00.00.0000
3999 The output path resp.
4000 file where everything will be placed.
4001 If the parameter is a path, it must have a trailing slash (or backslash
4002 for the Windows binaries) to be recognized as a path.
4005 \labelwidthstring 00.00.0000
4016 All functions in the source file will be compiled as
4021 the parameters and local variables will be allocated on the stack.
4022 see section Parameters and Local Variables for more details.
4023 If this option is used all source files in the project should be compiled
4027 \labelwidthstring 00.00.0000
4033 Uses a pseudo stack in the first 256 bytes in the external ram for allocating
4034 variables and passing parameters.
4035 See section on external stack for more details.
4037 \labelwidthstring 00.00.0000
4041 ---callee-saves function1[,function2][,function3]....
4044 The compiler by default uses a caller saves convention for register saving
4045 across function calls, however this can cause unneccessary register pushing
4046 & popping when calling small functions from larger functions.
4047 This option can be used to switch the register saving convention for the
4048 function names specified.
4049 The compiler will not save registers when calling these functions, no extra
4050 code will be generated at the entry & exit for these functions to save
4051 & restore the registers used by these functions, this can SUBSTANTIALLY
4052 reduce code & improve run time performance of the generated code.
4053 In the future the compiler (with interprocedural analysis) will be able
4054 to determine the appropriate scheme to use for each function call.
4055 DO NOT use this option for built-in functions such as _muluint..., if this
4056 option is used for a library function the appropriate library function
4057 needs to be recompiled with the same option.
4058 If the project consists of multiple source files then all the source file
4059 should be compiled with the same ---callee-saves option string.
4060 Also see #pragma\SpecialChar ~
4063 \labelwidthstring 00.00.0000
4072 When this option is used the compiler will generate debug information, that
4073 can be used with the SDCDB.
4074 The debug information is collected in a file with .cdb extension.
4075 For more information see documentation for SDCDB.
4077 \labelwidthstring 00.00.0000
4083 <filename> This option can be used to use additional rules to be used by
4084 the peep hole optimizer.
4085 See section Peep Hole optimizations for details on how to write these rules.
4087 \labelwidthstring 00.00.0000
4098 Stop after the stage of compilation proper; do not assemble.
4099 The output is an assembler code file for the input file specified.
4101 \labelwidthstring 00.00.0000
4105 -Wa_asmOption[,asmOption]
4108 Pass the asmOption to the assembler.
4110 \labelwidthstring 00.00.0000
4114 -Wl_linkOption[,linkOption]
4117 Pass the linkOption to the linker.
4119 \labelwidthstring 00.00.0000
4128 Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
4129 Note by default these libraries are compiled as non-reentrant.
4130 See section Installation for more details.
4132 \labelwidthstring 00.00.0000
4141 This option will cause the compiler to generate an information message for
4142 each function in the source file.
4143 The message contains some
4147 information about the function.
4148 The number of edges and nodes the compiler detected in the control flow
4149 graph of the function, and most importantly the
4151 cyclomatic complexity
4153 see section on Cyclomatic Complexity for more details.
4155 \labelwidthstring 00.00.0000
4164 Floating point library is compiled as reentrant.See section Installation
4167 \labelwidthstring 00.00.0000
4173 The compiler will not overlay parameters and local variables of any function,
4174 see section Parameters and local variables for more details.
4176 \labelwidthstring 00.00.0000
4182 This option can be used when the code generated is called by a monitor
4184 The compiler will generate a 'ret' upon return from the 'main' function.
4185 The default option is to lock up i.e.
4188 \labelwidthstring 00.00.0000
4194 Disable peep-hole optimization.
4196 \labelwidthstring 00.00.0000
4202 Pass the inline assembler code through the peep hole optimizer.
4203 This can cause unexpected changes to inline assembler code, please go through
4204 the peephole optimizer rules defined in the source file tree '<target>/peeph.def
4205 ' before using this option.
4207 \labelwidthstring 00.00.0000
4213 <Value> Causes the linker to check if the internal ram usage is within limits
4216 \labelwidthstring 00.00.0000
4222 <Value> Causes the linker to check if the external ram usage is within limits
4225 \labelwidthstring 00.00.0000
4231 <Value> Causes the linker to check if the code usage is within limits of
4234 \labelwidthstring 00.00.0000
4240 This will prevent the compiler from passing on the default include path
4241 to the preprocessor.
4243 \labelwidthstring 00.00.0000
4249 This will prevent the compiler from passing on the default library path
4252 \labelwidthstring 00.00.0000
4258 Shows the various actions the compiler is performing.
4260 \labelwidthstring 00.00.0000
4266 Shows the actual commands the compiler is executing.
4268 \labelwidthstring 00.00.0000
4274 Hides your ugly and inefficient c-code from the asm file, so you can always
4275 blame the compiler :).
4277 \labelwidthstring 00.00.0000
4283 Include i-codes in the asm file.
4284 Sounds like noise but is most helpfull for debugging the compiler itself.
4286 \labelwidthstring 00.00.0000
4292 Disable some of the more pedantic warnings (jwk burps: please be more specific
4294 \layout Subsubsection
4296 Intermediate Dump Options
4299 The following options are provided for the purpose of retargetting and debugging
4301 These provided a means to dump the intermediate code (iCode) generated
4302 by the compiler in human readable form at various stages of the compilation
4306 \labelwidthstring 00.00.0000
4312 This option will cause the compiler to dump the intermediate code into
4315 <source filename>.dumpraw
4317 just after the intermediate code has been generated for a function, i.e.
4318 before any optimizations are done.
4319 The basic blocks at this stage ordered in the depth first number, so they
4320 may not be in sequence of execution.
4322 \labelwidthstring 00.00.0000
4328 Will create a dump of iCode's, after global subexpression elimination,
4331 <source filename>.dumpgcse.
4333 \labelwidthstring 00.00.0000
4339 Will create a dump of iCode's, after deadcode elimination, into a file
4342 <source filename>.dumpdeadcode.
4344 \labelwidthstring 00.00.0000
4353 Will create a dump of iCode's, after loop optimizations, into a file named
4356 <source filename>.dumploop.
4358 \labelwidthstring 00.00.0000
4367 Will create a dump of iCode's, after live range analysis, into a file named
4370 <source filename>.dumprange.
4372 \labelwidthstring 00.00.0000
4378 Will dump the life ranges for all symbols.
4380 \labelwidthstring 00.00.0000
4389 Will create a dump of iCode's, after register assignment, into a file named
4392 <source filename>.dumprassgn.
4394 \labelwidthstring 00.00.0000
4400 Will create a dump of the live ranges of iTemp's
4402 \labelwidthstring 00.00.0000
4413 Will cause all the above mentioned dumps to be created.
4416 Environment variables
4419 SDCC recognizes the following environment variables:
4421 \labelwidthstring 00.00.0000
4427 SDCC installs a signal handler to be able to delete temporary files after
4428 an user break (^C) or an exception.
4429 If this environment variable is set, SDCC won't install the signal handler
4430 in order to be able to debug SDCC.
4432 \labelwidthstring 00.00.0000
4440 Path, where temporary files will be created.
4441 The order of the variables is the search order.
4442 In a standard *nix environment these variables are not set, and there's
4443 no need to set them.
4444 On Windows it's recommended to set one of them.
4446 \labelwidthstring 00.00.0000
4453 \begin_inset Quotes sld
4456 2.3 Install and search paths
4457 \begin_inset Quotes srd
4462 \labelwidthstring 00.00.0000
4469 \begin_inset Quotes sld
4472 2.3 Install and search paths
4473 \begin_inset Quotes srd
4478 \labelwidthstring 00.00.0000
4485 \begin_inset Quotes sld
4488 2.3 Install and search paths
4489 \begin_inset Quotes srd
4495 There are some more environment variables recognized by SDCC, but these
4496 are solely used for debugging purposes.
4497 They can change or disappear very quickly, and will never be documentated.
4500 MCS51/DS390 Storage Class Language Extensions
4503 In addition to the ANSI storage classes SDCC allows the following MCS51
4504 specific storage classes.
4505 \layout Subsubsection
4510 Variables declared with this storage class will be placed in the extern
4516 storage class for Large Memory model, e.g.:
4522 xdata unsigned char xduc;
4523 \layout Subsubsection
4532 storage class for Small Memory model.
4533 Variables declared with this storage class will be allocated in the internal
4541 \layout Subsubsection
4546 Variables declared with this storage class will be allocated into the indirectly
4547 addressable portion of the internal ram of a 8051, e.g.:
4554 \layout Subsubsection
4559 This is a data-type and a storage class specifier.
4560 When a variable is declared as a bit, it is allocated into the bit addressable
4561 memory of 8051, e.g.:
4568 \layout Subsubsection
4573 Like the bit keyword,
4577 signifies both a data-type and storage class, they are used to describe
4578 the special function registers and special bit variables of a 8051, eg:
4584 sfr at 0x80 P0; /* special function register P0 at location 0x80 */
4586 sbit at 0xd7 CY; /* CY (Carry Flag) */
4592 SDCC allows (via language extensions) pointers to explicitly point to any
4593 of the memory spaces of the 8051.
4594 In addition to the explicit pointers, the compiler uses (by default) generic
4595 pointers which can be used to point to any of the memory spaces.
4599 Pointer declaration examples:
4608 /* pointer physically in xternal ram pointing to object in internal ram
4611 data unsigned char * xdata p;
4615 /* pointer physically in code rom pointing to data in xdata space */
4617 xdata unsigned char * code p;
4621 /* pointer physically in code space pointing to data in code space */
4623 code unsigned char * code p;
4627 /* the folowing is a generic pointer physically located in xdata space */
4638 Well you get the idea.
4643 All unqualified pointers are treated as 3-byte (4-byte for the ds390)
4656 The highest order byte of the
4660 pointers contains the data space information.
4661 Assembler support routines are called whenever data is stored or retrieved
4667 These are useful for developing reusable library routines.
4668 Explicitly specifying the pointer type will generate the most efficient
4672 Parameters & Local Variables
4675 Automatic (local) variables and parameters to functions can either be placed
4676 on the stack or in data-space.
4677 The default action of the compiler is to place these variables in the internal
4678 RAM (for small model) or external RAM (for large model).
4679 This in fact makes them
4683 so by default functions are non-reentrant.
4687 They can be placed on the stack either by using the
4691 option or by using the
4695 keyword in the function declaration, e.g.:
4704 unsigned char foo(char i) reentrant
4717 Since stack space on 8051 is limited, the
4725 option should be used sparingly.
4726 Note that the reentrant keyword just means that the parameters & local
4727 variables will be allocated to the stack, it
4731 mean that the function is register bank independent.
4735 Local variables can be assigned storage classes and absolute addresses,
4742 unsigned char foo() {
4748 xdata unsigned char i;
4760 data at 0x31 unsiged char j;
4775 In the above example the variable
4779 will be allocated in the external ram,
4783 in bit addressable space and
4792 or when a function is declared as
4796 this should only be done for static variables.
4799 Parameters however are not allowed any storage class, (storage classes for
4800 parameters will be ignored), their allocation is governed by the memory
4801 model in use, and the reentrancy options.
4807 For non-reentrant functions SDCC will try to reduce internal ram space usage
4808 by overlaying parameters and local variables of a function (if possible).
4809 Parameters and local variables of a function will be allocated to an overlayabl
4810 e segment if the function has
4812 no other function calls and the function is non-reentrant and the memory
4816 If an explicit storage class is specified for a local variable, it will
4820 Note that the compiler (not the linkage editor) makes the decision for overlayin
4822 Functions that are called from an interrupt service routine should be preceded
4823 by a #pragma\SpecialChar ~
4824 NOOVERLAY if they are not reentrant.
4827 Also note that the compiler does not do any processing of inline assembler
4828 code, so the compiler might incorrectly assign local variables and parameters
4829 of a function into the overlay segment if the inline assembler code calls
4830 other c-functions that might use the overlay.
4831 In that case the #pragma\SpecialChar ~
4832 NOOVERLAY should be used.
4835 Parameters and Local variables of functions that contain 16 or 32 bit multiplica
4836 tion or division will NOT be overlayed since these are implemented using
4837 external functions, e.g.:
4847 void set_error(unsigned char errcd)
4863 void some_isr () interrupt 2 using 1
4892 In the above example the parameter
4900 would be assigned to the overlayable segment if the #pragma\SpecialChar ~
4902 not present, this could cause unpredictable runtime behavior when called
4904 The #pragma\SpecialChar ~
4905 NOOVERLAY ensures that the parameters and local variables for
4906 the function are NOT overlayed.
4909 Interrupt Service Routines
4912 SDCC allows interrupt service routines to be coded in C, with some extended
4919 void timer_isr (void) interrupt 2 using 1
4932 The number following the
4936 keyword is the interrupt number this routine will service.
4937 The compiler will insert a call to this routine in the interrupt vector
4938 table for the interrupt number specified.
4943 keyword is used to tell the compiler to use the specified register bank
4944 (8051 specific) when generating code for this function.
4945 Note that when some function is called from an interrupt service routine
4946 it should be preceded by a #pragma\SpecialChar ~
4947 NOOVERLAY if it is not reentrant.
4948 A special note here, int (16 bit) and long (32 bit) integer division, multiplic
4949 ation & modulus operations are implemented using external support routines
4950 developed in ANSI-C, if an interrupt service routine needs to do any of
4951 these operations then the support routines (as mentioned in a following
4952 section) will have to be recompiled using the
4956 option and the source file will need to be compiled using the
4963 If you have multiple source files in your project, interrupt service routines
4964 can be present in any of them, but a prototype of the isr MUST be present
4965 or included in the file that contains the function
4972 Interrupt Numbers and the corresponding address & descriptions for the Standard
4973 8051 are listed below.
4974 SDCC will automatically adjust the interrupt vector table to the maximum
4975 interrupt number specified.
4981 \begin_inset Tabular
4982 <lyxtabular version="3" rows="6" columns="3">
4984 <column alignment="center" valignment="top" leftline="true" width="0in">
4985 <column alignment="center" valignment="top" leftline="true" width="0in">
4986 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0in">
4987 <row topline="true" bottomline="true">
4988 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
4996 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5004 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
5013 <row topline="true">
5014 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5022 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5030 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
5039 <row topline="true">
5040 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5048 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5056 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
5065 <row topline="true">
5066 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5074 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5082 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
5091 <row topline="true">
5092 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5100 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5108 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
5117 <row topline="true" bottomline="true">
5118 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5126 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
5134 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
5151 If the interrupt service routine is defined without
5155 a register bank or with register bank 0 (using 0), the compiler will save
5156 the registers used by itself on the stack upon entry and restore them at
5157 exit, however if such an interrupt service routine calls another function
5158 then the entire register bank will be saved on the stack.
5159 This scheme may be advantageous for small interrupt service routines which
5160 have low register usage.
5163 If the interrupt service routine is defined to be using a specific register
5168 are save and restored, if such an interrupt service routine calls another
5169 function (using another register bank) then the entire register bank of
5170 the called function will be saved on the stack.
5171 This scheme is recommended for larger interrupt service routines.
5174 Calling other functions from an interrupt service routine is not recommended,
5175 avoid it if possible.
5179 Also see the _naked modifier.
5187 <TODO: this isn't implemented at all!>
5193 A special keyword may be associated with a function declaring it as
5198 SDCC will generate code to disable all interrupts upon entry to a critical
5199 function and enable them back before returning.
5200 Note that nesting critical functions may cause unpredictable results.
5225 The critical attribute maybe used with other attributes like
5233 A special keyword may be associated with a function declaring it as
5242 function modifier attribute prevents the compiler from generating prologue
5243 and epilogue code for that function.
5244 This means that the user is entirely responsible for such things as saving
5245 any registers that may need to be preserved, selecting the proper register
5246 bank, generating the
5250 instruction at the end, etc.
5251 Practically, this means that the contents of the function must be written
5252 in inline assembler.
5253 This is particularly useful for interrupt functions, which can have a large
5254 (and often unnecessary) prologue/epilogue.
5255 For example, compare the code generated by these two functions:
5261 data unsigned char counter;
5263 void simpleInterrupt(void) interrupt 1
5277 void nakedInterrupt(void) interrupt 2 _naked
5310 ; MUST explicitly include ret in _naked function.
5324 For an 8051 target, the generated simpleInterrupt looks like:
5469 whereas nakedInterrupt looks like:
5494 ; MUST explicitly include ret(i) in _naked function.
5500 While there is nothing preventing you from writing C code inside a _naked
5501 function, there are many ways to shoot yourself in the foot doing this,
5502 and it is recommended that you stick to inline assembler.
5505 Functions using private banks
5512 attribute (which tells the compiler to use a register bank other than the
5513 default bank zero) should only be applied to
5517 functions (see note 1 below).
5518 This will in most circumstances make the generated ISR code more efficient
5519 since it will not have to save registers on the stack.
5526 attribute will have no effect on the generated code for a
5530 function (but may occasionally be useful anyway
5536 possible exception: if a function is called ONLY from 'interrupt' functions
5537 using a particular bank, it can be declared with the same 'using' attribute
5538 as the calling 'interrupt' functions.
5539 For instance, if you have several ISRs using bank one, and all of them
5540 call memcpy(), it might make sense to create a specialized version of memcpy()
5541 'using 1', since this would prevent the ISR from having to save bank zero
5542 to the stack on entry and switch to bank zero before calling the function
5549 (pending: I don't think this has been done yet)
5556 function using a non-zero bank will assume that it can trash that register
5557 bank, and will not save it.
5558 Since high-priority interrupts can interrupt low-priority ones on the 8051
5559 and friends, this means that if a high-priority ISR
5563 a particular bank occurs while processing a low-priority ISR
5567 the same bank, terrible and bad things can happen.
5568 To prevent this, no single register bank should be
5572 by both a high priority and a low priority ISR.
5573 This is probably most easily done by having all high priority ISRs use
5574 one bank and all low priority ISRs use another.
5575 If you have an ISR which can change priority at runtime, you're on your
5576 own: I suggest using the default bank zero and taking the small performance
5580 It is most efficient if your ISR calls no other functions.
5581 If your ISR must call other functions, it is most efficient if those functions
5582 use the same bank as the ISR (see note 1 below); the next best is if the
5583 called functions use bank zero.
5584 It is very inefficient to call a function using a different, non-zero bank
5592 Data items can be assigned an absolute address with the
5596 keyword, in addition to a storage class, e.g.:
5602 xdata at 0x8000 unsigned char PORTA_8255 ;
5608 In the above example the PORTA_8255 will be allocated to the location 0x8000
5609 of the external ram.
5610 Note that this feature is provided to give the programmer access to
5614 devices attached to the controller.
5615 The compiler does not actually reserve any space for variables declared
5616 in this way (they are implemented with an equate in the assembler).
5617 Thus it is left to the programmer to make sure there are no overlaps with
5618 other variables that are declared without the absolute address.
5619 The assembler listing file (.lst) and the linker output files (.rst) and
5620 (.map) are a good places to look for such overlaps.
5624 Absolute address can be specified for variables in all storage classes,
5637 The above example will allocate the variable at offset 0x02 in the bit-addressab
5639 There is no real advantage to assigning absolute addresses to variables
5640 in this manner, unless you want strict control over all the variables allocated.
5646 The compiler inserts a call to the C routine
5648 _sdcc__external__startup()
5653 at the start of the CODE area.
5654 This routine is in the runtime library.
5655 By default this routine returns 0, if this routine returns a non-zero value,
5656 the static & global variable initialization will be skipped and the function
5657 main will be invoked Other wise static & global variables will be initialized
5658 before the function main is invoked.
5661 _sdcc__external__startup()
5663 routine to your program to override the default if you need to setup hardware
5664 or perform some other critical operation prior to static & global variable
5668 Inline Assembler Code
5671 SDCC allows the use of in-line assembler with a few restriction as regards
5673 All labels defined within inline assembler code
5681 where nnnn is a number less than 100 (which implies a limit of utmost 100
5682 inline assembler labels
5690 It is strongly recommended that each assembly instruction (including labels)
5691 be placed in a separate line (as the example shows).
5696 command line option is used, the inline assembler code will be passed through
5697 the peephole optimizer.
5698 This might cause some unexpected changes in the inline assembler code.
5699 Please go throught the peephole optimizer rules defined in file
5703 carefully before using this option.
5743 The inline assembler code can contain any valid code understood by the assembler
5744 , this includes any assembler directives and comment lines.
5745 The compiler does not do any validation of the code within the
5755 Inline assembler code cannot reference any C-Labels, however it can reference
5756 labels defined by the inline assembler, e.g.:
5782 ; some assembler code
5802 /* some more c code */
5804 clabel:\SpecialChar ~
5806 /* inline assembler cannot reference this label */
5818 $0003: ;label (can be reference by inline assembler only)
5830 /* some more c code */
5838 In other words inline assembly code can access labels defined in inline
5839 assembly within the scope of the funtion.
5843 The same goes the other way, ie.
5844 labels defines in inline assembly CANNOT be accessed by C statements.
5847 int (16 bit) and long (32 bit) Support
5850 For signed & unsigned int (16 bit) and long (32 bit) variables, division,
5851 multiplication and modulus operations are implemented by support routines.
5852 These support routines are all developed in ANSI-C to facilitate porting
5853 to other MCUs, although some model specific assembler optimations are used.
5854 The following files contain the described routine, all of them can be found
5855 in <installdir>/share/sdcc/lib.
5861 <pending: tabularise this>
5867 _mulsint.c - signed 16 bit multiplication (calls _muluint)
5869 _muluint.c - unsigned 16 bit multiplication
5871 _divsint.c - signed 16 bit division (calls _divuint)
5873 _divuint.c - unsigned 16 bit division
5875 _modsint.c - signed 16 bit modulus (call _moduint)
5877 _moduint.c - unsigned 16 bit modulus
5879 _mulslong.c - signed 32 bit multiplication (calls _mululong)
5881 _mululong.c - unsigned32 bit multiplication
5883 _divslong.c - signed 32 division (calls _divulong)
5885 _divulong.c - unsigned 32 division
5887 _modslong.c - signed 32 bit modulus (calls _modulong)
5889 _modulong.c - unsigned 32 bit modulus
5897 Since they are compiled as
5901 , interrupt service routines should not do any of the above operations.
5902 If this is unavoidable then the above routines will need to be compiled
5907 option, after which the source program will have to be compiled with
5914 Floating Point Support
5917 SDCC supports IEEE (single precision 4bytes) floating point numbers.The floating
5918 point support routines are derived from gcc's floatlib.c and consists of
5919 the following routines:
5925 <pending: tabularise this>
5931 _fsadd.c - add floating point numbers
5933 _fssub.c - subtract floating point numbers
5935 _fsdiv.c - divide floating point numbers
5937 _fsmul.c - multiply floating point numbers
5939 _fs2uchar.c - convert floating point to unsigned char
5941 _fs2char.c - convert floating point to signed char
5943 _fs2uint.c - convert floating point to unsigned int
5945 _fs2int.c - convert floating point to signed int
5947 _fs2ulong.c - convert floating point to unsigned long
5949 _fs2long.c - convert floating point to signed long
5951 _uchar2fs.c - convert unsigned char to floating point
5953 _char2fs.c - convert char to floating point number
5955 _uint2fs.c - convert unsigned int to floating point
5957 _int2fs.c - convert int to floating point numbers
5959 _ulong2fs.c - convert unsigned long to floating point number
5961 _long2fs.c - convert long to floating point number
5969 Note if all these routines are used simultaneously the data space might
5971 For serious floating point usage it is strongly recommended that the large
5978 SDCC allows two memory models for MCS51 code, small and large.
5979 Modules compiled with different memory models should
5983 be combined together or the results would be unpredictable.
5984 The library routines supplied with the compiler are compiled as both small
5986 The compiled library modules are contained in seperate directories as small
5987 and large so that you can link to either set.
5991 When the large model is used all variables declared without a storage class
5992 will be allocated into the external ram, this includes all parameters and
5993 local variables (for non-reentrant functions).
5994 When the small model is used variables without storage class are allocated
5995 in the internal ram.
5998 Judicious usage of the processor specific storage classes and the 'reentrant'
5999 function type will yield much more efficient code, than using the large
6001 Several optimizations are disabled when the program is compiled using the
6002 large model, it is therefore strongly recommdended that the small model
6003 be used unless absolutely required.
6009 The only model supported is Flat 24.
6010 This generates code for the 24 bit contiguous addressing mode of the Dallas
6012 In this mode, up to four meg of external RAM or code space can be directly
6014 See the data sheets at www.dalsemi.com for further information on this part.
6018 In older versions of the compiler, this option was used with the MCS51 code
6024 Now, however, the '390 has it's own code generator, selected by the
6033 Note that the compiler does not generate any code to place the processor
6034 into 24 bitmode (although
6038 in the ds390 libraries will do that for you).
6043 , the boot loader or similar code must ensure that the processor is in 24
6044 bit contiguous addressing mode before calling the SDCC startup code.
6052 option, variables will by default be placed into the XDATA segment.
6057 Segments may be placed anywhere in the 4 meg address space using the usual
6059 Note that if any segments are located above 64K, the -r flag must be passed
6060 to the linker to generate the proper segment relocations, and the Intel
6061 HEX output format must be used.
6062 The -r flag can be passed to the linker by using the option
6066 on the sdcc command line.
6067 However, currently the linker can not handle code segments > 64k.
6070 Defines Created by the Compiler
6073 The compiler creates the following #defines.
6076 SDCC - this Symbol is always defined.
6079 SDCC_mcs51 or SDCC_ds390 or SDCC_z80, etc - depending on the model used
6083 __mcs51 or __ds390 or __z80, etc - depending on the model used (e.g.
6087 SDCC_STACK_AUTO - this symbol is defined when
6094 SDCC_MODEL_SMALL - when
6101 SDCC_MODEL_LARGE - when
6108 SDCC_USE_XSTACK - when
6115 SDCC_STACK_TENBIT - when
6122 SDCC_MODEL_FLAT24 - when
6135 SDCC performs a host of standard optimizations in addition to some MCU specific
6138 \layout Subsubsection
6140 Sub-expression Elimination
6143 The compiler does local and global common subexpression elimination, e.g.:
6158 will be translated to
6174 Some subexpressions are not as obvious as the above example, e.g.:
6188 In this case the address arithmetic a->b[i] will be computed only once;
6189 the equivalent code in C would be.
6205 The compiler will try to keep these temporary variables in registers.
6206 \layout Subsubsection
6208 Dead-Code Elimination
6223 i = 1; \SpecialChar ~
6228 global = 1;\SpecialChar ~
6241 global = 3;\SpecialChar ~
6256 int global; void f ()
6269 \layout Subsubsection
6330 Note: the dead stores created by this copy propagation will be eliminated
6331 by dead-code elimination.
6332 \layout Subsubsection
6337 Two types of loop optimizations are done by SDCC loop invariant lifting
6338 and strength reduction of loop induction variables.
6339 In addition to the strength reduction the optimizer marks the induction
6340 variables and the register allocator tries to keep the induction variables
6341 in registers for the duration of the loop.
6342 Because of this preference of the register allocator, loop induction optimizati
6343 on causes an increase in register pressure, which may cause unwanted spilling
6344 of other temporary variables into the stack / data space.
6345 The compiler will generate a warning message when it is forced to allocate
6346 extra space either on the stack or data space.
6347 If this extra space allocation is undesirable then induction optimization
6348 can be eliminated either for the entire source file (with ---noinduction
6349 option) or for a given function only using #pragma\SpecialChar ~
6360 for (i = 0 ; i < 100 ; i ++)
6378 for (i = 0; i < 100; i++)
6388 As mentioned previously some loop invariants are not as apparent, all static
6389 address computations are also moved out of the loop.
6393 Strength Reduction, this optimization substitutes an expression by a cheaper
6400 for (i=0;i < 100; i++)
6420 for (i=0;i< 100;i++) {
6424 ar[itemp1] = itemp2;
6440 The more expensive multiplication is changed to a less expensive addition.
6441 \layout Subsubsection
6446 This optimization is done to reduce the overhead of checking loop boundaries
6447 for every iteration.
6448 Some simple loops can be reversed and implemented using a
6449 \begin_inset Quotes eld
6452 decrement and jump if not zero
6453 \begin_inset Quotes erd
6457 SDCC checks for the following criterion to determine if a loop is reversible
6458 (note: more sophisticated compilers use data-dependency analysis to make
6459 this determination, SDCC uses a more simple minded analysis).
6462 The 'for' loop is of the form
6468 for (<symbol> = <expression> ; <sym> [< | <=] <expression> ; [<sym>++ |
6478 The <for body> does not contain
6479 \begin_inset Quotes eld
6483 \begin_inset Quotes erd
6487 \begin_inset Quotes erd
6493 All goto's are contained within the loop.
6496 No function calls within the loop.
6499 The loop control variable <sym> is not assigned any value within the loop
6502 The loop control variable does NOT participate in any arithmetic operation
6506 There are NO switch statements in the loop.
6507 \layout Subsubsection
6509 Algebraic Simplifications
6512 SDCC does numerous algebraic simplifications, the following is a small sub-set
6513 of these optimizations.
6519 i = j + 0 ; /* changed to */ i = j;
6521 i /= 2; /* changed to */ i >>= 1;
6523 i = j - j ; /* changed to */ i = 0;
6525 i = j / 1 ; /* changed to */ i = j;
6531 Note the subexpressions given above are generally introduced by macro expansions
6532 or as a result of copy/constant propagation.
6533 \layout Subsubsection
6538 SDCC changes switch statements to jump tables when the following conditions
6543 The case labels are in numerical sequence, the labels need not be in order,
6544 and the starting number need not be one or zero.
6550 switch(i) {\SpecialChar ~
6657 Both the above switch statements will be implemented using a jump-table.
6660 The number of case labels is at least three, since it takes two conditional
6661 statements to handle the boundary conditions.
6664 The number of case labels is less than 84, since each label takes 3 bytes
6665 and a jump-table can be utmost 256 bytes long.
6669 Switch statements which have gaps in the numeric sequence or those that
6670 have more that 84 case labels can be split into more than one switch statement
6671 for efficient code generation, e.g.:
6709 If the above switch statement is broken down into two switch statements
6743 case 9: \SpecialChar ~
6753 case 12:\SpecialChar ~
6763 then both the switch statements will be implemented using jump-tables whereas
6764 the unmodified switch statement will not be.
6765 \layout Subsubsection
6767 Bit-shifting Operations.
6770 Bit shifting is one of the most frequently used operation in embedded programmin
6772 SDCC tries to implement bit-shift operations in the most efficient way
6792 generates the following code:
6810 In general SDCC will never setup a loop if the shift count is known.
6850 Note that SDCC stores numbers in little-endian format (i.e.
6851 lowest order first).
6852 \layout Subsubsection
6857 A special case of the bit-shift operation is bit rotation, SDCC recognizes
6858 the following expression to be a left bit-rotation:
6869 i = ((i << 1) | (i >> 7));
6877 will generate the following code:
6893 SDCC uses pattern matching on the parse tree to determine this operation.Variatio
6894 ns of this case will also be recognized as bit-rotation, i.e.:
6900 i = ((i >> 7) | (i << 1)); /* left-bit rotation */
6901 \layout Subsubsection
6906 It is frequently required to obtain the highest order bit of an integral
6907 type (long, int, short or char types).
6908 SDCC recognizes the following expression to yield the highest order bit
6909 and generates optimized code for it, e.g.:
6930 hob = (gint >> 15) & 1;
6943 will generate the following code:
6982 000A E5*01\SpecialChar ~
7010 000C 33\SpecialChar ~
7041 000D E4\SpecialChar ~
7072 000E 13\SpecialChar ~
7103 000F F5*02\SpecialChar ~
7133 Variations of this case however will
7138 It is a standard C expression, so I heartily recommend this be the only
7139 way to get the highest order bit, (it is portable).
7140 Of course it will be recognized even if it is embedded in other expressions,
7147 xyz = gint + ((gint >> 15) & 1);
7153 will still be recognized.
7154 \layout Subsubsection
7159 The compiler uses a rule based, pattern matching and re-writing mechanism
7160 for peep-hole optimization.
7165 a peep-hole optimizer by Christopher W.
7166 Fraser (cwfraser@microsoft.com).
7167 A default set of rules are compiled into the compiler, additional rules
7168 may be added with the
7170 ---peep-file <filename>
7173 The rule language is best illustrated with examples.
7201 The above rule will change the following assembly sequence:
7231 Note: All occurrences of a
7235 (pattern variable) must denote the same string.
7236 With the above rule, the assembly sequence:
7254 will remain unmodified.
7258 Other special case optimizations may be added by the user (via
7264 some variants of the 8051 MCU allow only
7273 The following two rules will change all
7295 replace { lcall %1 } by { acall %1 }
7297 replace { ljmp %1 } by { ajmp %1 }
7305 inline-assembler code
7307 is also passed through the peep hole optimizer, thus the peephole optimizer
7308 can also be used as an assembly level macro expander.
7309 The rules themselves are MCU dependent whereas the rule language infra-structur
7310 e is MCU independent.
7311 Peephole optimization rules for other MCU can be easily programmed using
7316 The syntax for a rule is as follows:
7322 rule := replace [ restart ] '{' <assembly sequence> '
7360 <assembly sequence> '
7378 '}' [if <functionName> ] '
7386 <assembly sequence> := assembly instruction (each instruction including
7387 labels must be on a separate line).
7391 The optimizer will apply to the rules one by one from the top in the sequence
7392 of their appearance, it will terminate when all rules are exhausted.
7393 If the 'restart' option is specified, then the optimizer will start matching
7394 the rules again from the top, this option for a rule is expensive (performance)
7395 , it is intended to be used in situations where a transformation will trigger
7396 the same rule again.
7397 An example of this (not a good one, it has side effects) is the following
7424 Note that the replace pattern cannot be a blank, but can be a comment line.
7425 Without the 'restart' option only the inner most 'pop' 'push' pair would
7426 be eliminated, i.e.:
7478 the restart option the rule will be applied again to the resulting code
7479 and then all the pop-push pairs will be eliminated to yield:
7497 A conditional function can be attached to a rule.
7498 Attaching rules are somewhat more involved, let me illustrate this with
7529 The optimizer does a look-up of a function name table defined in function
7534 in the source file SDCCpeeph.c, with the name
7539 If it finds a corresponding entry the function is called.
7540 Note there can be no parameters specified for these functions, in this
7545 is crucial, since the function
7549 expects to find the label in that particular variable (the hash table containin
7550 g the variable bindings is passed as a parameter).
7551 If you want to code more such functions, take a close look at the function
7552 labelInRange and the calling mechanism in source file SDCCpeeph.c.
7553 I know this whole thing is a little kludgey, but maybe some day we will
7554 have some better means.
7555 If you are looking at this file, you will also see the default rules that
7556 are compiled into the compiler, you can add your own rules in the default
7557 set there if you get tired of specifying the ---peep-file option.
7563 SDCC supports the following #pragma directives.
7566 SAVE - this will save all current options to the SAVE/RESTORE stack.
7570 RESTORE - will restore saved options from the last save.
7571 SAVEs & RESTOREs can be nested.
7572 SDCC uses a SAVE/RESTORE stack: SAVE pushes current options to the stack,
7573 RESTORE pulls current options from the stack.
7577 NOGCSE - will stop global subexpression elimination.
7580 NOINDUCTION - will stop loop induction optimizations.
7583 NOJTBOUND - will not generate code for boundary value checking, when switch
7584 statements are turned into jump-tables.
7587 NOOVERLAY - the compiler will not overlay the parameters and local variables
7591 LESS_PEDANTIC - the compiler will not warn you anymore for obvious mistakes,
7592 you'r on your own now ;-(
7595 NOLOOPREVERSE - Will not do loop reversal optimization
7598 EXCLUDE NONE | {acc[,b[,dpl[,dph]]] - The exclude pragma disables generation
7599 of pair of push/pop instruction in ISR function (using interrupt keyword).
7600 The directive should be placed immediately before the ISR function definition
7601 and it affects ALL ISR functions following it.
7602 To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
7603 EXCLUDE\SpecialChar ~
7607 NOIV - Do not generate interrupt vector table entries for all ISR functions
7608 defined after the pragma.
7609 This is useful in cases where the interrupt vector table must be defined
7610 manually, or when there is a secondary, manually defined interrupt vector
7612 for the autovector feature of the Cypress EZ-USB FX2).
7615 CALLEE-SAVES function1[,function2[,function3...]] - The compiler by default
7616 uses a caller saves convention for register saving across function calls,
7617 however this can cause unneccessary register pushing & popping when calling
7618 small functions from larger functions.
7619 This option can be used to switch off the register saving convention for
7620 the function names specified.
7621 The compiler will not save registers when calling these functions, extra
7622 code need to be manually inserted at the entry & exit for these functions
7623 to save & restore the registers used by these functions, this can SUBSTANTIALLY
7624 reduce code & improve run time performance of the generated code.
7625 In the future the compiler (with interprocedural analysis) may be able
7626 to determine the appropriate scheme to use for each function call.
7627 If ---callee-saves command line option is used, the function names specified
7628 in #pragma\SpecialChar ~
7629 CALLEE-SAVES is appended to the list of functions specified in
7633 The pragma's are intended to be used to turn-off certain optimizations which
7634 might cause the compiler to generate extra stack / data space to store
7635 compiler generated temporary variables.
7636 This usually happens in large functions.
7637 Pragma directives should be used as shown in the following example, they
7638 are used to control options & optimizations for a given function; pragmas
7639 should be placed before and/or after a function, placing pragma's inside
7640 a function body could have unpredictable results.
7646 #pragma SAVE /* save the current settings */
7648 #pragma NOGCSE /* turnoff global subexpression elimination */
7650 #pragma NOINDUCTION /* turn off induction optimizations */
7672 #pragma RESTORE /* turn the optimizations back on */
7678 The compiler will generate a warning message when extra space is allocated.
7679 It is strongly recommended that the SAVE and RESTORE pragma's be used when
7680 changing options for a function.
7685 <pending: this is messy and incomplete>
7690 Compiler support routines (_gptrget, _mulint etc)
7693 Stdclib functions (puts, printf, strcat etc)
7696 Math functions (sin, pow, sqrt etc)
7699 Interfacing with Assembly Routines
7700 \layout Subsubsection
7702 Global Registers used for Parameter Passing
7705 The compiler always uses the global registers
7713 to pass the first parameter to a routine.
7714 The second parameter onwards is either allocated on the stack (for reentrant
7715 routines or if ---stack-auto is used) or in the internal / external ram
7716 (depending on the memory model).
7718 \layout Subsubsection
7720 Assembler Routine(non-reentrant)
7723 In the following example the function cfunc calls an assembler routine asm_func,
7724 which takes two parameters.
7730 extern int asm_func(unsigned char, unsigned char);
7734 int c_func (unsigned char i, unsigned char j)
7742 return asm_func(i,j);
7756 return c_func(10,9);
7764 The corresponding assembler function is:
7770 .globl _asm_func_PARM_2
7834 add a,_asm_func_PARM_2
7870 Note here that the return values are placed in 'dpl' - One byte return value,
7871 'dpl' LSB & 'dph' MSB for two byte values.
7872 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
7873 b' & 'acc' for four byte values.
7876 The parameter naming convention is _<function_name>_PARM_<n>, where n is
7877 the parameter number starting from 1, and counting from the left.
7878 The first parameter is passed in
7879 \begin_inset Quotes eld
7883 \begin_inset Quotes erd
7886 for One bye parameter,
7887 \begin_inset Quotes eld
7891 \begin_inset Quotes erd
7895 \begin_inset Quotes eld
7899 \begin_inset Quotes erd
7903 \begin_inset Quotes eld
7907 \begin_inset Quotes erd
7910 for four bytes, the varible name for the second parameter will be _<function_na
7915 Assemble the assembler routine with the following command:
7922 asx8051 -losg asmfunc.asm
7929 Then compile and link the assembler routine to the C source file with the
7937 sdcc cfunc.c asmfunc.rel
7938 \layout Subsubsection
7940 Assembler Routine(reentrant)
7943 In this case the second parameter onwards will be passed on the stack, the
7944 parameters are pushed from right to left i.e.
7945 after the call the left most parameter will be on the top of the stack.
7952 extern int asm_func(unsigned char, unsigned char);
7956 int c_func (unsigned char i, unsigned char j) reentrant
7964 return asm_func(i,j);
7978 return c_func(10,9);
7986 The corresponding assembler routine is:
8096 The compiling and linking procedure remains the same, however note the extra
8097 entry & exit linkage required for the assembler code, _bp is the stack
8098 frame pointer and is used to compute the offset into the stack for parameters
8099 and local variables.
8105 The external stack is located at the start of the external ram segment,
8106 and is 256 bytes in size.
8107 When ---xstack option is used to compile the program, the parameters and
8108 local variables of all reentrant functions are allocated in this area.
8109 This option is provided for programs with large stack space requirements.
8110 When used with the ---stack-auto option, all parameters and local variables
8111 are allocated on the external stack (note support libraries will need to
8112 be recompiled with the same options).
8115 The compiler outputs the higher order address byte of the external ram segment
8116 into PORT P2, therefore when using the External Stack option, this port
8117 MAY NOT be used by the application program.
8123 Deviations from the compliancy.
8126 functions are not always reentrant.
8129 structures cannot be assigned values directly, cannot be passed as function
8130 parameters or assigned to each other and cannot be a return value from
8157 s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
8168 struct s foo1 (struct s parms) /* is invalid in SDCC although allowed in
8190 return rets;/* is invalid in SDCC although allowed in ANSI */
8195 'long long' (64 bit integers) not supported.
8198 'double' precision floating point not supported.
8201 No support for setjmp and longjmp (for now).
8204 Old K&R style function declarations are NOT allowed.
8210 foo(i,j) /* this old style of function declarations */
8212 int i,j; /* are valid in ANSI but not valid in SDCC */
8226 functions declared as pointers must be dereferenced during the call.
8237 /* has to be called like this */
8239 (*foo)(); /* ansi standard allows calls to be made like 'foo()' */
8242 Cyclomatic Complexity
8245 Cyclomatic complexity of a function is defined as the number of independent
8246 paths the program can take during execution of the function.
8247 This is an important number since it defines the number test cases you
8248 have to generate to validate the function.
8249 The accepted industry standard for complexity number is 10, if the cyclomatic
8250 complexity reported by SDCC exceeds 10 you should think about simplification
8251 of the function logic.
8252 Note that the complexity level is not related to the number of lines of
8254 Large functions can have low complexity, and small functions can have large
8260 SDCC uses the following formula to compute the complexity:
8265 complexity = (number of edges in control flow graph) - (number of nodes
8266 in control flow graph) + 2;
8270 Having said that the industry standard is 10, you should be aware that in
8271 some cases it be may unavoidable to have a complexity level of less than
8273 For example if you have switch statement with more than 10 case labels,
8274 each case label adds one to the complexity level.
8275 The complexity level is by no means an absolute measure of the algorithmic
8276 complexity of the function, it does however provide a good starting point
8277 for which functions you might look at for further optimization.
8283 Here are a few guidelines that will help the compiler generate more efficient
8284 code, some of the tips are specific to this compiler others are generally
8285 good programming practice.
8288 Use the smallest data type to represent your data-value.
8289 If it is known in advance that the value is going to be less than 256 then
8290 use an 'unsigned char' instead of a 'short' or 'int'.
8293 Use unsigned when it is known in advance that the value is not going to
8295 This helps especially if you are doing division or multiplication.
8298 NEVER jump into a LOOP.
8301 Declare the variables to be local whenever possible, especially loop control
8302 variables (induction).
8305 Since the compiler does not always do implicit integral promotion, the programme
8306 r should do an explicit cast when integral promotion is required.
8309 Reducing the size of division, multiplication & modulus operations can reduce
8310 code size substantially.
8311 Take the following code for example.
8317 foobar(unsigned int p1, unsigned char ch)
8321 unsigned char ch1 = p1 % ch ;
8332 For the modulus operation the variable ch will be promoted to unsigned int
8333 first then the modulus operation will be performed (this will lead to a
8334 call to support routine _moduint()), and the result will be casted to a
8336 If the code is changed to
8342 foobar(unsigned int p1, unsigned char ch)
8346 unsigned char ch1 = (unsigned char)p1 % ch ;
8357 It would substantially reduce the code generated (future versions of the
8358 compiler will be smart enough to detect such optimization oppurtunities).
8361 Notes on MCS51 memory layout
8364 The 8051 family of micro controller have a minimum of 128 bytes of internal
8365 memory which is structured as follows
8369 - Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R7 to R7
8372 - Bytes 20-2F - 16 bytes to hold 128 bit variables and
8374 - Bytes 30-7F - 60 bytes for general purpose use.
8378 Normally the SDCC compiler will only utilise the first bank of registers,
8379 but it is possible to specify that other banks of registers should be used
8380 in interrupt routines.
8381 By default, the compiler will place the stack after the last bank of used
8383 if the first 2 banks of registers are used, it will position the base of
8384 the internal stack at address 16 (0X10).
8385 This implies that as the stack grows, it will use up the remaining register
8386 banks, and the 16 bytes used by the 128 bit variables, and 60 bytes for
8387 general purpose use.
8390 By default, the compiler uses the 60 general purpose bytes to hold "near
8392 The compiler/optimiser may also declare some Local Variables in this area
8397 If any of the 128 bit variables are used, or near data is being used then
8398 care needs to be taken to ensure that the stack does not grow so much that
8399 it starts to over write either your bit variables or "near data".
8400 There is no runtime checking to prevent this from happening.
8403 The amount of stack being used is affected by the use of the "internal stack"
8404 to save registers before a subroutine call is made (---stack-auto will
8405 declare parameters and local variables on the stack) and the number of
8409 If you detect that the stack is over writing you data, then the following
8411 ---xstack will cause an external stack to be used for saving registers
8412 and (if ---stack-auto is being used) storing parameters and local variables.
8413 However this will produce more code which will be slower to execute.
8417 ---stack-loc will allow you specify the start of the stack, i.e.
8418 you could start it after any data in the general purpose area.
8419 However this may waste the memory not used by the register banks and if
8420 the size of the "near data" increases, it may creep into the bottom of
8424 ---stack-after-data, similar to the ---stack-loc, but it automatically places
8425 the stack after the end of the "near data".
8426 Again this could waste any spare register space.
8429 ---data-loc allows you to specify the start address of the near data.
8430 This could be used to move the "near data" further away from the stack
8431 giving it more room to grow.
8432 This will only work if no bit variables are being used and the stack can
8433 grow to use the bit variable space.
8441 If you find that the stack is over writing your bit variables or "near data"
8442 then the approach which best utilised the internal memory is to position
8443 the "near data" after the last bank of used registers or, if you use bit
8444 variables, after the last bit variable by using the ---data-loc, e.g.
8445 if two register banks are being used and no bit variables, ---data-loc
8446 16, and use the ---stack-after-data option.
8449 If bit variables are being used, another method would be to try and squeeze
8450 the data area in the unused register banks if it will fit, and start the
8451 stack after the last bit variable.
8454 Retargetting for other MCUs.
8457 The issues for retargetting the compiler are far too numerous to be covered
8459 What follows is a brief description of each of the seven phases of the
8460 compiler and its MCU dependency.
8463 Parsing the source and building the annotated parse tree.
8464 This phase is largely MCU independent (except for the language extensions).
8465 Syntax & semantic checks are also done in this phase, along with some initial
8466 optimizations like back patching labels and the pattern matching optimizations
8467 like bit-rotation etc.
8470 The second phase involves generating an intermediate code which can be easy
8471 manipulated during the later phases.
8472 This phase is entirely MCU independent.
8473 The intermediate code generation assumes the target machine has unlimited
8474 number of registers, and designates them with the name iTemp.
8475 The compiler can be made to dump a human readable form of the code generated
8476 by using the ---dumpraw option.
8479 This phase does the bulk of the standard optimizations and is also MCU independe
8481 This phase can be broken down into several sub-phases:
8485 Break down intermediate code (iCode) into basic blocks.
8487 Do control flow & data flow analysis on the basic blocks.
8489 Do local common subexpression elimination, then global subexpression elimination
8491 Dead code elimination
8495 If loop optimizations caused any changes then do 'global subexpression eliminati
8496 on' and 'dead code elimination' again.
8499 This phase determines the live-ranges; by live range I mean those iTemp
8500 variables defined by the compiler that still survive after all the optimization
8502 Live range analysis is essential for register allocation, since these computati
8503 on determines which of these iTemps will be assigned to registers, and for
8507 Phase five is register allocation.
8508 There are two parts to this process.
8512 The first part I call 'register packing' (for lack of a better term).
8513 In this case several MCU specific expression folding is done to reduce
8518 The second part is more MCU independent and deals with allocating registers
8519 to the remaining live ranges.
8520 A lot of MCU specific code does creep into this phase because of the limited
8521 number of index registers available in the 8051.
8524 The Code generation phase is (unhappily), entirely MCU dependent and very
8525 little (if any at all) of this code can be reused for other MCU.
8526 However the scheme for allocating a homogenized assembler operand for each
8527 iCode operand may be reused.
8530 As mentioned in the optimization section the peep-hole optimizer is rule
8531 based system, which can reprogrammed for other MCUs.
8534 SDCDB - Source Level Debugger
8537 SDCC is distributed with a source level debugger.
8538 The debugger uses a command line interface, the command repertoire of the
8539 debugger has been kept as close to gdb (the GNU debugger) as possible.
8540 The configuration and build process is part of the standard compiler installati
8541 on, which also builds and installs the debugger in the target directory
8542 specified during configuration.
8543 The debugger allows you debug BOTH at the C source and at the ASM source
8547 Compiling for Debugging
8552 debug option must be specified for all files for which debug information
8554 The complier generates a .cdb file for each of these files.
8555 The linker updates the .cdb file with the address information.
8556 This .cdb is used by the debugger.
8559 How the Debugger Works
8562 When the ---debug option is specified the compiler generates extra symbol
8563 information some of which are put into the the assembler source and some
8564 are put into the .cdb file, the linker updates the .cdb file with the address
8565 information for the symbols.
8566 The debugger reads the symbolic information generated by the compiler &
8567 the address information generated by the linker.
8568 It uses the SIMULATOR (Daniel's S51) to execute the program, the program
8569 execution is controlled by the debugger.
8570 When a command is issued for the debugger, it translates it into appropriate
8571 commands for the simulator.
8574 Starting the Debugger
8577 The debugger can be started using the following command line.
8578 (Assume the file you are debugging has the file name foo).
8592 The debugger will look for the following files.
8595 foo.c - the source file.
8598 foo.cdb - the debugger symbol information file.
8601 foo.ihx - the intel hex format object file.
8604 Command Line Options.
8607 ---directory=<source file directory> this option can used to specify the
8608 directory search list.
8609 The debugger will look into the directory list specified for source, cdb
8611 The items in the directory list must be separated by ':', e.g.
8612 if the source files can be in the directories /home/src1 and /home/src2,
8613 the ---directory option should be ---directory=/home/src1:/home/src2.
8614 Note there can be no spaces in the option.
8618 -cd <directory> - change to the <directory>.
8621 -fullname - used by GUI front ends.
8624 -cpu <cpu-type> - this argument is passed to the simulator please see the
8625 simulator docs for details.
8628 -X <Clock frequency > this options is passed to the simulator please see
8629 the simulator docs for details.
8632 -s <serial port file> passed to simulator see the simulator docs for details.
8635 -S <serial in,out> passed to simulator see the simulator docs for details.
8641 As mention earlier the command interface for the debugger has been deliberately
8642 kept as close the GNU debugger gdb, as possible.
8643 This will help the integration with existing graphical user interfaces
8644 (like ddd, xxgdb or xemacs) existing for the GNU debugger.
8645 \layout Subsubsection
8647 break [line | file:line | function | file:function]
8650 Set breakpoint at specified line or function:
8659 sdcdb>break foo.c:100
8663 sdcdb>break foo.c:funcfoo
8664 \layout Subsubsection
8666 clear [line | file:line | function | file:function ]
8669 Clear breakpoint at specified line or function:
8678 sdcdb>clear foo.c:100
8682 sdcdb>clear foo.c:funcfoo
8683 \layout Subsubsection
8688 Continue program being debugged, after breakpoint.
8689 \layout Subsubsection
8694 Execute till the end of the current function.
8695 \layout Subsubsection
8700 Delete breakpoint number 'n'.
8701 If used without any option clear ALL user defined break points.
8702 \layout Subsubsection
8704 info [break | stack | frame | registers ]
8707 info break - list all breakpoints
8710 info stack - show the function call stack.
8713 info frame - show information about the current execution frame.
8716 info registers - show content of all registers.
8717 \layout Subsubsection
8722 Step program until it reaches a different source line.
8723 \layout Subsubsection
8728 Step program, proceeding through subroutine calls.
8729 \layout Subsubsection
8734 Start debugged program.
8735 \layout Subsubsection
8740 Print type information of the variable.
8741 \layout Subsubsection
8746 print value of variable.
8747 \layout Subsubsection
8752 load the given file name.
8753 Note this is an alternate method of loading file for debugging.
8754 \layout Subsubsection
8759 print information about current frame.
8760 \layout Subsubsection
8765 Toggle between C source & assembly source.
8766 \layout Subsubsection
8771 Send the string following '!' to the simulator, the simulator response is
8773 Note the debugger does not interpret the command being sent to the simulator,
8774 so if a command like 'go' is sent the debugger can loose its execution
8775 context and may display incorrect values.
8776 \layout Subsubsection
8783 My name is Bobby Brown"
8786 Interfacing with XEmacs.
8789 Two files (in emacs lisp) are provided for the interfacing with XEmacs,
8790 sdcdb.el and sdcdbsrc.el.
8791 These two files can be found in the $(prefix)/bin directory after the installat
8793 These files need to be loaded into XEmacs for the interface to work.
8794 This can be done at XEmacs startup time by inserting the following into
8795 your '.xemacs' file (which can be found in your HOME directory):
8801 (load-file sdcdbsrc.el)
8807 .xemacs is a lisp file so the () around the command is REQUIRED.
8808 The files can also be loaded dynamically while XEmacs is running, set the
8809 environment variable 'EMACSLOADPATH' to the installation bin directory
8810 (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
8811 To start the interface enter the following command:
8825 You will prompted to enter the file name to be debugged.
8830 The command line options that are passed to the simulator directly are bound
8831 to default values in the file sdcdbsrc.el.
8832 The variables are listed below, these values maybe changed as required.
8835 sdcdbsrc-cpu-type '51
8838 sdcdbsrc-frequency '11059200
8844 The following is a list of key mapping for the debugger interface.
8852 ;; Current Listing ::
8869 binding\SpecialChar ~
8908 ------\SpecialChar ~
8948 sdcdb-next-from-src\SpecialChar ~
8974 sdcdb-back-from-src\SpecialChar ~
9000 sdcdb-cont-from-src\SpecialChar ~
9010 SDCDB continue command
9026 sdcdb-step-from-src\SpecialChar ~
9052 sdcdb-whatis-c-sexp\SpecialChar ~
9062 SDCDB ptypecommand for data at
9126 sdcdbsrc-delete\SpecialChar ~
9140 SDCDB Delete all breakpoints if no arg
9188 given or delete arg (C-u arg x)
9204 sdcdbsrc-frame\SpecialChar ~
9219 SDCDB Display current frame if no arg,
9268 given or display frame arg
9333 sdcdbsrc-goto-sdcdb\SpecialChar ~
9343 Goto the SDCDB output buffer
9359 sdcdb-print-c-sexp\SpecialChar ~
9370 SDCDB print command for data at
9434 sdcdbsrc-goto-sdcdb\SpecialChar ~
9444 Goto the SDCDB output buffer
9460 sdcdbsrc-mode\SpecialChar ~
9476 Toggles Sdcdbsrc mode (turns it off)
9480 ;; C-c C-f\SpecialChar ~
9488 sdcdb-finish-from-src\SpecialChar ~
9496 SDCDB finish command
9500 ;; C-x SPC\SpecialChar ~
9508 sdcdb-break\SpecialChar ~
9526 Set break for line with point
9528 ;; ESC t\SpecialChar ~
9538 sdcdbsrc-mode\SpecialChar ~
9554 Toggle Sdcdbsrc mode
9556 ;; ESC m\SpecialChar ~
9566 sdcdbsrc-srcmode\SpecialChar ~
9590 The Z80 and gbz80 port
9593 SDCC can target both the Zilog Z80 and the Nintendo Gameboy's Z80-like gbz80.
9594 The port is incomplete - long support is incomplete (mul, div and mod are
9595 unimplimented), and both float and bitfield support is missing.
9596 Apart from that the code generated is correct.
9599 As always, the code is the authoritave reference - see z80/ralloc.c and z80/gen.c.
9600 The stack frame is similar to that generated by the IAR Z80 compiler.
9601 IX is used as the base pointer, HL is used as a temporary register, and
9602 BC and DE are available for holding varibles.
9603 IY is currently unusued.
9604 Return values are stored in HL.
9605 One bad side effect of using IX as the base pointer is that a functions
9606 stack frame is limited to 127 bytes - this will be fixed in a later version.
9612 SDCC has grown to be a large project.
9613 The compiler alone (without the preprocessor, assembler and linker) is
9614 about 40,000 lines of code (blank stripped).
9615 The open source nature of this project is a key to its continued growth
9617 You gain the benefit and support of many active software developers and
9619 Is SDCC perfect? No, that's why we need your help.
9620 The developers take pride in fixing reported bugs.
9621 You can help by reporting the bugs and helping other SDCC users.
9622 There are lots of ways to contribute, and we encourage you to take part
9623 in making SDCC a great software package.
9629 Send an email to the mailing list at 'user-sdcc@sdcc.sourceforge.net' or 'devel-sd
9630 cc@sdcc.sourceforge.net'.
9631 Bugs will be fixed ASAP.
9632 When reporting a bug, it is very useful to include a small test program
9633 which reproduces the problem.
9634 If you can isolate the problem by looking at the generated assembly code,
9635 this can be very helpful.
9636 Compiling your program with the ---dumpall option can sometimes be useful
9637 in locating optimization problems.
9643 The anatomy of the compiler
9648 This is an excerpt from an atricle published in Circuit Cellar MagaZine
9650 It's a little outdated (the compiler is much more efficient now and user/devell
9651 oper friendly), but pretty well exposes the guts of it all.
9657 The current version of SDCC can generate code for Intel 8051 and Z80 MCU.
9658 It is fairly easy to retarget for other 8-bit MCU.
9659 Here we take a look at some of the internals of the compiler.
9666 Parsing the input source file and creating an AST (Annotated Syntax Tree).
9667 This phase also involves propagating types (annotating each node of the
9668 parse tree with type information) and semantic analysis.
9669 There are some MCU specific parsing rules.
9670 For example the storage classes, the extended storage classes are MCU specific
9671 while there may be a xdata storage class for 8051 there is no such storage
9672 class for z80 or Atmel AVR.
9673 SDCC allows MCU specific storage class extensions, i.e.
9674 xdata will be treated as a storage class specifier when parsing 8051 C
9675 code but will be treated as a C identifier when parsing z80 or ATMEL AVR
9682 Intermediate code generation.
9683 In this phase the AST is broken down into three-operand form (iCode).
9684 These three operand forms are represented as doubly linked lists.
9685 ICode is the term given to the intermediate form generated by the compiler.
9686 ICode example section shows some examples of iCode generated for some simple
9693 Bulk of the target independent optimizations is performed in this phase.
9694 The optimizations include constant propagation, common sub-expression eliminati
9695 on, loop invariant code movement, strength reduction of loop induction variables
9696 and dead-code elimination.
9702 During intermediate code generation phase, the compiler assumes the target
9703 machine has infinite number of registers and generates a lot of temporary
9705 The live range computation determines the lifetime of each of these compiler-ge
9706 nerated temporaries.
9707 A picture speaks a thousand words.
9708 ICode example sections show the live range annotations for each of the
9710 It is important to note here, each iCode is assigned a number in the order
9711 of its execution in the function.
9712 The live ranges are computed in terms of these numbers.
9713 The from number is the number of the iCode which first defines the operand
9714 and the to number signifies the iCode which uses this operand last.
9720 The register allocation determines the type and number of registers needed
9722 In most MCUs only a few registers can be used for indirect addressing.
9723 In case of 8051 for example the registers R0 & R1 can be used to indirectly
9724 address the internal ram and DPTR to indirectly address the external ram.
9725 The compiler will try to allocate the appropriate register to pointer variables
9727 ICode example section shows the operands annotated with the registers assigned
9729 The compiler will try to keep operands in registers as much as possible;
9730 there are several schemes the compiler uses to do achieve this.
9731 When the compiler runs out of registers the compiler will check to see
9732 if there are any live operands which is not used or defined in the current
9733 basic block being processed, if there are any found then it will push that
9734 operand and use the registers in this block, the operand will then be popped
9735 at the end of the basic block.
9739 There are other MCU specific considerations in this phase.
9740 Some MCUs have an accumulator; very short-lived operands could be assigned
9741 to the accumulator instead of general-purpose register.
9747 Figure II gives a table of iCode operations supported by the compiler.
9748 The code generation involves translating these operations into corresponding
9749 assembly code for the processor.
9750 This sounds overly simple but that is the essence of code generation.
9751 Some of the iCode operations are generated on a MCU specific manner for
9752 example, the z80 port does not use registers to pass parameters so the
9753 SEND and RECV iCode operations will not be generated, and it also does
9754 not support JUMPTABLES.
9761 <Where is Figure II ?>
9767 This section shows some details of iCode.
9768 The example C code does not do anything useful; it is used as an example
9769 to illustrate the intermediate code generated by the compiler.
9782 /* This function does nothing useful.
9789 for the purpose of explaining iCode */
9792 short function (data int *x)
9800 short i=10; /* dead initialization eliminated */
9805 short sum=10; /* dead initialization eliminated */
9818 while (*x) *x++ = *p++;
9832 /* compiler detects i,j to be induction variables */
9836 for (i = 0, j = 10 ; i < 10 ; i++, j---) {
9848 mul += i * 3; /* this multiplication remains */
9854 gint += j * 3;/* this multiplication changed to addition */
9871 In addition to the operands each iCode contains information about the filename
9872 and line it corresponds to in the source file.
9873 The first field in the listing should be interpreted as follows:
9878 Filename(linenumber: iCode Execution sequence number : ICode hash table
9879 key : loop depth of the iCode).
9884 Then follows the human readable form of the ICode operation.
9885 Each operand of this triplet form can be of three basic types a) compiler
9886 generated temporary b) user defined variable c) a constant value.
9887 Note that local variables and parameters are replaced by compiler generated
9889 Live ranges are computed only for temporaries (i.e.
9890 live ranges are not computed for global variables).
9891 Registers are allocated for temporaries only.
9892 Operands are formatted in the following manner:
9897 Operand Name [lr live-from : live-to ] { type information } [ registers
9903 As mentioned earlier the live ranges are computed in terms of the execution
9904 sequence number of the iCodes, for example
9906 the iTemp0 is live from (i.e.
9907 first defined in iCode with execution sequence number 3, and is last used
9908 in the iCode with sequence number 5).
9909 For induction variables such as iTemp21 the live range computation extends
9910 the lifetime from the start to the end of the loop.
9912 The register allocator used the live range information to allocate registers,
9913 the same registers may be used for different temporaries if their live
9914 ranges do not overlap, for example r0 is allocated to both iTemp6 and to
9915 iTemp17 since their live ranges do not overlap.
9916 In addition the allocator also takes into consideration the type and usage
9917 of a temporary, for example itemp6 is a pointer to near space and is used
9918 as to fetch data from (i.e.
9919 used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer registers (r0).
9920 Some short lived temporaries are allocated to special registers which have
9921 meaning to the code generator e.g.
9922 iTemp13 is allocated to a pseudo register CC which tells the back end that
9923 the temporary is used only for a conditional jump the code generation makes
9924 use of this information to optimize a compare and jump ICode.
9926 There are several loop optimizations performed by the compiler.
9927 It can detect induction variables iTemp21(i) and iTemp23(j).
9928 Also note the compiler does selective strength reduction, i.e.
9929 the multiplication of an induction variable in line 18 (gint = j * 3) is
9930 changed to addition, a new temporary iTemp17 is allocated and assigned
9931 a initial value, a constant 3 is then added for each iteration of the loop.
9932 The compiler does not change the multiplication in line 17 however since
9933 the processor does support an 8 * 8 bit multiplication.
9935 Note the dead code elimination optimization eliminated the dead assignments
9936 in line 7 & 8 to I and sum respectively.
9943 Sample.c (5:1:0:0) _entry($9) :
9948 Sample.c(5:2:1:0) proc _function [lr0:0]{function short}
9953 Sample.c(11:3:2:0) iTemp0 [lr3:5]{_near * int}[r2] = recv
9958 Sample.c(11:4:53:0) preHeaderLbl0($11) :
9963 Sample.c(11:5:55:0) iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near
9969 Sample.c(11:6:5:1) _whilecontinue_0($1) :
9974 Sample.c(11:7:7:1) iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near *
9980 Sample.c(11:8:8:1) if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
9985 Sample.c(11:9:14:1) iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far
9991 Sample.c(11:10:15:1) _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2
9997 Sample.c(11:13:18:1) iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far
10003 Sample.c(11:14:19:1) *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int
10009 Sample.c(11:15:12:1) iTemp6 [lr5:16]{_near * int}[r0] = iTemp6 [lr5:16]{_near
10010 * int}[r0] + 0x2 {short}
10015 Sample.c(11:16:20:1) goto _whilecontinue_0($1)
10020 Sample.c(11:17:21:0)_whilebreak_0($3) :
10025 Sample.c(12:18:22:0) iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
10030 Sample.c(13:19:23:0) iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
10035 Sample.c(15:20:54:0)preHeaderLbl1($13) :
10040 Sample.c(15:21:56:0) iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
10045 Sample.c(15:22:57:0) iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
10050 Sample.c(15:23:58:0) iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
10055 Sample.c(15:24:26:1)_forcond_0($4) :
10060 Sample.c(15:25:27:1) iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4]
10066 Sample.c(15:26:28:1) if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
10071 Sample.c(16:27:31:1) iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2]
10072 + ITemp21 [lr21:38]{short}[r4]
10077 Sample.c(17:29:33:1) iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4]
10083 Sample.c(17:30:34:1) iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3]
10084 + iTemp15 [lr29:30]{short}[r1]
10089 Sample.c(18:32:36:1:1) iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7
10095 Sample.c(18:33:37:1) _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{
10101 Sample.c(15:36:42:1) iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4]
10107 Sample.c(15:37:45:1) iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5
10113 Sample.c(19:38:47:1) goto _forcond_0($4)
10118 Sample.c(19:39:48:0)_forbreak_0($7) :
10123 Sample.c(20:40:49:0) iTemp24 [lr40:41]{short}[DPTR] = iTemp2 [lr18:40]{short}[r2]
10124 + ITemp11 [lr19:40]{short}[r3]
10129 Sample.c(20:41:50:0) ret iTemp24 [lr40:41]{short}
10134 Sample.c(20:42:51:0)_return($8) :
10139 Sample.c(20:43:52:0) eproc _function [lr0:0]{ ia0 re0 rm0}{function short}
10145 Finally the code generated for this function:
10186 ; ----------------------------------------------
10191 ; function function
10196 ; ----------------------------------------------
10206 ; iTemp0 [lr3:5]{_near * int}[r2] = recv
10218 ; iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near * int}[r2]
10230 ;_whilecontinue_0($1) :
10240 ; iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near * int}[r0]]
10245 ; if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
10304 ; iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far * int}
10323 ; _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2 {short}
10370 ; iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far * int}[DPTR]]
10410 ; *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int}[r2 r3]
10436 ; iTemp6 [lr5:16]{_near * int}[r0] =
10441 ; iTemp6 [lr5:16]{_near * int}[r0] +
10458 ; goto _whilecontinue_0($1)
10470 ; _whilebreak_0($3) :
10480 ; iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
10492 ; iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
10504 ; iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
10516 ; iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
10535 ; iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
10564 ; iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4] < 0xa {short}
10569 ; if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
10614 ; iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2] +
10619 ; iTemp21 [lr21:38]{short}[r4]
10645 ; iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4] * 0x3 {short}
10678 ; iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3] +
10683 ; iTemp15 [lr29:30]{short}[r1]
10702 ; iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7 r0]- 0x3 {short}
10749 ; _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{int}[r7 r0]
10796 ; iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4] + 0x1 {short}
10808 ; iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5 r6]- 0x1 {short}
10822 cjne r5,#0xff,00104$
10834 ; goto _forcond_0($4)
10846 ; _forbreak_0($7) :
10856 ; ret iTemp24 [lr40:41]{short}
10899 A few words about basic block successors, predecessors and dominators
10902 Successors are basic blocks that might execute after this basic block.
10904 Predecessors are basic blocks that might execute before reaching this basic
10907 Dominators are basic blocks that WILL execute before reaching this basic
10933 a) succList of [BB2] = [BB4], of [BB3] = [BB4], of [BB1] = [BB2,BB3]
10936 b) predList of [BB2] = [BB1], of [BB3] = [BB1], of [BB4] = [BB2,BB3]
10939 c) domVect of [BB4] = BB1 ...
10940 here we are not sure if BB2 or BB3 was executed but we are SURE that BB1
10948 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net#Who}
10958 Thanks to all the other volunteer developers who have helped with coding,
10959 testing, web-page creation, distribution sets, etc.
10960 You know who you are :-)
10967 This document was initially written by Sandeep Dutta
10970 All product names mentioned herein may be trademarks of their respective
10976 \begin_inset LatexCommand \printindex{}