1 #LyX 1.3 created this file. For more info see http://www.lyx.org/
5 \pdfoptionpdfminorversion=3
7 pdftitle={SDCC Compiler User Guide},
8 pdfauthor={SDCC development team},
9 pdfsubject={installation, user manual},
10 pdfkeywords={8032 8051 ansi c compiler CPU DS390
11 embedded GPL HC08 manual mcs51 microcontroller PIC Z80},
13 linkcolor=blue] {hyperref}
17 \emergencystretch=30pt
22 \inputencoding default
25 \paperfontsize default
27 \papersize letterpaper
32 \use_numerical_citations 0
33 \paperorientation portrait
40 \paragraph_separation indent
42 \quotes_language swedish
50 Please note: double dashed longoptions (e.g.
51 --version) are written this way: -
65 three consecutive dashes simply result in a long resp.
69 Architecture specific stuff (like memory models, code examples) should maybe
73 into seperate sections/chapters/appendices (it is hard to document PIC or
77 a 8051 centered document) - for now simply add.
80 SDCC Compiler User Guide
94 The above strings enclosed in $ are automatically updated by cvs
98 \begin_inset LatexCommand \tableofcontents{}
131 ompiler) is an open source, retargettable, optimizing ANSI-C compiler by
136 designed for 8 bit Microprocessors.
137 The current version targets Intel MCS51 based Microprocessors (8031, 8032,
139 \begin_inset LatexCommand \index{8031, 8032, 8051, 8052, mcs51 CPU}
143 , etc.), Dallas DS80C390 variants, Freescale (formerly Motorola) HC08 and
144 Zilog Z80 based MCUs.
145 It can be retargetted for other microprocessors, support for Microchip
146 PIC, Atmel AVR is under development.
147 The entire source code for the compiler is distributed under GPL.
149 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
154 \begin_inset LatexCommand \index{aslink}
158 , an open source retargettable assembler & linker.
159 SDCC has extensive language extensions suitable for utilizing various microcont
160 rollers and underlying hardware effectively.
165 In addition to the MCU specific optimizations SDCC also does a host of standard
169 global sub expression elimination,
172 loop optimizations (loop invariant, strength reduction of induction variables
176 constant folding & propagation,
182 dead code elimination
192 For the back-end SDCC uses a global register allocation scheme which should
193 be well suited for other 8 bit MCUs.
198 The peep hole optimizer uses a rule based substitution mechanism which is
204 Supported data-types are:
207 char (8 bits, 1 byte),
210 short and int (16 bits, 2 bytes),
213 long (32 bit, 4 bytes)
220 The compiler also allows
222 inline assembler code
224 to be embedded anywhere in a function.
225 In addition, routines developed in assembly can also be called.
229 SDCC also provides an option (-
239 -cyclomatic) to report the relative complexity of a function.
240 These functions can then be further optimized, or hand coded in assembly
246 SDCC also comes with a companion source level debugger SDCDB, the debugger
247 currently uses ucSim a freeware simulator for 8051 and other micro-controllers.
248 SDCDB and ucSim are currently not available on Win32 platforms.
253 The latest version can be downloaded from
254 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
264 Please note: the compiler will probably always be some steps ahead of this
269 \begin_inset LatexCommand \index{Status of documentation}
279 Obviously this has pros and cons
288 All packages used in this compiler system are
296 ; source code for all the sub-packages (pre-processor, assemblers, linkers
297 etc) is distributed with the package.
298 This documentation is maintained using a freeware word processor (LyX).
300 This program is free software; you can redistribute it and/or modify it
301 under the terms of the GNU General Public License
302 \begin_inset LatexCommand \index{GNU General Public License, GPL}
306 as published by the Free Software Foundation; either version 2, or (at
307 your option) any later version.
308 This program is distributed in the hope that it will be useful, but WITHOUT
309 ANY WARRANTY; without even the implied warranty
310 \begin_inset LatexCommand \index{warranty}
314 of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
315 See the GNU General Public License for more details.
316 You should have received a copy of the GNU General Public License along
317 with this program; if not, write to the Free Software Foundation, 59 Temple
318 Place - Suite 330, Boston, MA 02111-1307, USA.
319 In other words, you are welcome to use, share and improve this program.
320 You are forbidden to forbid anyone else to use, share and improve what
322 Help stamp out software-hoarding!
325 Typographic conventions
326 \begin_inset LatexCommand \index{Typographic conventions}
333 Throughout this manual, we will use the following convention.
334 Commands you have to type in are printed in
342 Code samples are printed in
347 Interesting items and new terms are printed in
352 Compatibility with previous versions
353 \begin_inset LatexCommand \index{Compatibility with previous versions}
360 This version has numerous bug fixes compared with the previous version.
361 But we also introduced some incompatibilities with older versions.
362 Not just for the fun of it, but to make the compiler more stable, efficient
364 \begin_inset LatexCommand \index{ANSI-compliance}
369 \begin_inset LatexCommand \ref{sub:ANSI-Compliance}
373 for ANSI-Compliance).
379 short is now equivalent to int (16 bits), it used to be equivalent to char
380 (8 bits) which is not ANSI compliant.
383 the default directory for gcc-builds where include, library and documentation
384 files are stored is now in /usr/local/share.
387 char type parameters to vararg functions are casted to int unless explicitly
404 will push a as an int and as a char resp.
417 -regextend has been removed.
430 -noregparms has been removed.
443 -stack-after-data has been removed.
447 \begin_inset LatexCommand \index{bit}
452 \begin_inset LatexCommand \index{sbit}
457 \begin_inset LatexCommand \index{\_\_sbit}
461 types now consistently behave like the C99 _Bool type with respect to type
463 \begin_inset LatexCommand \index{type conversion}
468 \begin_inset LatexCommand \index{type promotion}
473 The most common incompatibility resulting from this change is related to
475 \begin_inset LatexCommand \index{Bit toggling}
489 b = ~b; /* equivalent to b=1 instead of toggling b */
493 b = !b; /* toggles b */
497 In previous versions, both forms would have toggled the bit.
502 <pending: more incompatibilities?>
508 What do you need before you start installation of SDCC? A computer, and
510 The preferred method of installation is to compile SDCC from source using
512 For Windows some pre-compiled binary distributions are available for your
514 You should have some experience with command line tools and compiler use.
520 The SDCC home page at
521 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/}
525 is a great place to find distribution sets.
526 You can also find links to the user mailing lists that offer help or discuss
527 SDCC with other SDCC users.
528 Web links to other SDCC related sites can also be found here.
529 This document can be found in the DOC directory of the source package as
531 A pdf version of this document is available at
532 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/doc/sdccman.pdf}
537 Some of the other tools (simulator and assembler) included with SDCC contain
538 their own documentation and can be found in the source distribution.
539 If you want the latest unreleased software, the complete source package
540 is available directly by anonymous CVS on cvs.sdcc.sourceforge.net.
543 Wishes for the future
546 There are (and always will be) some things that could be done.
547 Here are some I can think of:
554 char KernelFunction3(char p) at 0x340;
562 \begin_inset LatexCommand \index{code banking (limited support)}
572 If you can think of some more, please see the section
573 \begin_inset LatexCommand \ref{sub:Requesting-Features}
577 about filing feature requests
578 \begin_inset LatexCommand \index{Requesting features}
583 \begin_inset LatexCommand \index{Feature request}
593 \begin_inset LatexCommand \index{Installation}
600 For most users it is sufficient to skip to either section
601 \begin_inset LatexCommand \ref{sub:Building-SDCC-on-Linux}
606 \begin_inset LatexCommand \ref{sub:Windows-Install}
611 More detailled instructions follow below.
615 \begin_inset LatexCommand \index{Options SDCC configuration}
622 The install paths, search paths and other options are defined when running
624 The defaults can be overridden by:
626 \labelwidthstring 00.00.0000
638 -prefix see table below
640 \labelwidthstring 00.00.0000
652 -exec_prefix see table below
654 \labelwidthstring 00.00.0000
666 -bindir see table below
668 \labelwidthstring 00.00.0000
680 -datadir see table below
682 \labelwidthstring 00.00.0000
684 docdir environment variable, see table below
686 \labelwidthstring 00.00.0000
688 include_dir_suffix environment variable, see table below
690 \labelwidthstring 00.00.0000
692 lib_dir_suffix environment variable, see table below
694 \labelwidthstring 00.00.0000
696 sdccconf_h_dir_separator environment variable, either / or
701 This character will only be used in sdccconf.h; don't forget it's a C-header,
702 therefore a double-backslash is needed there.
704 \labelwidthstring 00.00.0000
716 -disable-mcs51-port Excludes the Intel mcs51 port
718 \labelwidthstring 00.00.0000
730 -disable-gbz80-port Excludes the Gameboy gbz80 port
732 \labelwidthstring 00.00.0000
744 -disable-z80-port Excludes the z80 port
746 \labelwidthstring 00.00.0000
758 -disable-avr-port Excludes the AVR port
760 \labelwidthstring 00.00.0000
772 -disable-ds390-port Excludes the DS390 port
774 \labelwidthstring 00.00.0000
786 -disable-hc08-port Excludes the HC08 port
788 \labelwidthstring 00.00.0000
800 -disable-pic-port Excludes the PIC port
802 \labelwidthstring 00.00.0000
814 -disable-xa51-port Excludes the XA51 port
816 \labelwidthstring 00.00.0000
828 -disable-ucsim Disables configuring and building of ucsim
830 \labelwidthstring 00.00.0000
842 -disable-device-lib-build Disables automatically building device libraries
844 \labelwidthstring 00.00.0000
856 -disable-packihx Disables building packihx
858 \labelwidthstring 00.00.0000
870 -enable-libgc Use the Bohem memory allocator.
871 Lower runtime footprint.
874 Furthermore the environment variables CC, CFLAGS, ...
875 the tools and their arguments can be influenced.
876 Please see `configure -
886 -help` and the man/info pages of `configure` for details.
890 The names of the standard libraries STD_LIB, STD_INT_LIB, STD_LONG_LIB,
891 STD_FP_LIB, STD_DS390_LIB, STD_XA51_LIB and the environment variables SDCC_DIR_
892 NAME, SDCC_INCLUDE_NAME, SDCC_LIB_NAME are defined by `configure` too.
893 At the moment it's not possible to change the default settings (it was
894 simply never required).
898 These configure options are compiled into the binaries, and can only be
899 changed by rerunning 'configure' and recompiling SDCC.
900 The configure options are written in
904 to distinguish them from run time environment variables (see section search
910 \begin_inset Quotes sld
914 \begin_inset Quotes srd
917 are used by the SDCC team to build the official Win32 binaries.
918 The SDCC team uses Mingw32 to build the official Windows binaries, because
925 a gcc compiler and last but not least
928 the binaries can be built by cross compiling on Sourceforge's compile farm.
931 See the examples, how to pass the Win32 settings to 'configure'.
932 The other Win32 builds using Borland, VC or whatever don't use 'configure',
933 but a header file sdcc_vc_in.h is the same as sdccconf.h built by 'configure'
945 <lyxtabular version="3" rows="8" columns="3">
947 <column alignment="block" valignment="top" leftline="true" width="0in">
948 <column alignment="block" valignment="top" leftline="true" width="0in">
949 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
950 <row topline="true" bottomline="true">
951 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
959 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
967 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
977 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
987 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
995 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1006 <row topline="true">
1007 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1017 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1027 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1038 <row topline="true">
1039 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1049 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1061 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1076 <row topline="true">
1077 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1087 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1099 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1110 <row topline="true">
1111 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1121 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1133 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1148 <row topline="true">
1149 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1159 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1167 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1176 <row topline="true" bottomline="true">
1177 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1187 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1195 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1213 'configure' also computes relative paths.
1214 This is needed for full relocatability of a binary package and to complete
1215 search paths (see section search paths below):
1221 \begin_inset Tabular
1222 <lyxtabular version="3" rows="4" columns="3">
1224 <column alignment="block" valignment="top" leftline="true" width="0in">
1225 <column alignment="block" valignment="top" leftline="true" width="0in">
1226 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
1227 <row topline="true" bottomline="true">
1228 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1236 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1244 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1253 <row topline="true" bottomline="true">
1254 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1264 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1272 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1281 <row bottomline="true">
1282 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1292 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1300 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1309 <row bottomline="true">
1310 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1320 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1328 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1361 \begin_inset Quotes srd
1365 \begin_inset Quotes srd
1379 \begin_inset Quotes srd
1383 \begin_inset Quotes srd
1411 To cross compile on linux for Mingw32 (see also 'sdcc/support/scripts/sdcc_mingw
1420 \begin_inset Quotes srd
1423 i586-mingw32msvc-gcc
1424 \begin_inset Quotes srd
1428 \begin_inset Quotes srd
1431 i586-mingw32msvc-g++
1432 \begin_inset Quotes srd
1440 \begin_inset Quotes srd
1443 i586-mingw32msvc-ranlib
1444 \begin_inset Quotes srd
1452 \begin_inset Quotes srd
1455 i586-mingw32msvc-strip
1456 \begin_inset Quotes srd
1474 \begin_inset Quotes srd
1478 \begin_inset Quotes srd
1496 \begin_inset Quotes srd
1500 \begin_inset Quotes srd
1508 \begin_inset Quotes srd
1512 \begin_inset Quotes srd
1520 \begin_inset Quotes srd
1524 \begin_inset Quotes srd
1532 \begin_inset Quotes srd
1536 \begin_inset Quotes srd
1543 sdccconf_h_dir_separator=
1544 \begin_inset Quotes srd
1556 \begin_inset Quotes srd
1573 -disable-device-lib-build
1601 -host=i586-mingw32msvc -
1611 -build=unknown-unknown-linux-gnu
1615 \begin_inset Quotes sld
1619 \begin_inset Quotes srd
1622 compile on Cygwin for Mingw32 (see also sdcc/support/scripts/sdcc_cygwin_mingw32
1631 \begin_inset Quotes srd
1635 \begin_inset Quotes srd
1643 \begin_inset Quotes srd
1647 \begin_inset Quotes srd
1665 \begin_inset Quotes srd
1669 \begin_inset Quotes srd
1687 \begin_inset Quotes srd
1691 \begin_inset Quotes srd
1699 \begin_inset Quotes srd
1703 \begin_inset Quotes srd
1711 \begin_inset Quotes srd
1715 \begin_inset Quotes srd
1723 \begin_inset Quotes srd
1727 \begin_inset Quotes srd
1734 sdccconf_h_dir_separator=
1735 \begin_inset Quotes srd
1747 \begin_inset Quotes srd
1767 'configure' is quite slow on Cygwin (at least on windows before Win2000/XP).
1778 -C' turns on caching, which gives a little bit extra speed.
1779 However if options are changed, it can be necessary to delete the config.cache
1784 \begin_inset LatexCommand \label{sub:Install-paths}
1789 \begin_inset LatexCommand \index{Install paths}
1795 \added_space_top medskip \align center
1797 \begin_inset Tabular
1798 <lyxtabular version="3" rows="5" columns="4">
1800 <column alignment="center" valignment="top" leftline="true" width="0">
1801 <column alignment="center" valignment="top" leftline="true" width="0">
1802 <column alignment="center" valignment="top" leftline="true" width="0">
1803 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
1804 <row topline="true" bottomline="true">
1805 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1815 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1825 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1835 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1846 <row topline="true">
1847 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1855 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1865 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1873 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1886 <row topline="true">
1887 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1895 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1902 $DATADIR/ $INCLUDE_DIR_SUFFIX
1905 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1910 /usr/local/share/sdcc/include
1913 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1926 <row topline="true">
1927 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1935 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1942 $DATADIR/$LIB_DIR_SUFFIX
1945 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1950 /usr/local/share/sdcc/lib
1953 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
1966 <row topline="true" bottomline="true">
1967 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1975 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1985 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
1990 /usr/local/share/sdcc/doc
1993 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2015 *compiler, preprocessor, assembler, and linker
2021 is auto-appended by the compiler, e.g.
2022 small, large, z80, ds390 etc
2025 The install paths can still be changed during `make install` with e.g.:
2028 make install prefix=$(HOME)/local/sdcc
2031 Of course this doesn't change the search paths compiled into the binaries.
2035 Moreover the install path can be changed by defining DESTDIR
2036 \begin_inset LatexCommand \index{DESTDIR}
2043 make install DESTDIR=$(HOME)/sdcc.rpm/
2046 Please note that DESTDIR must have a trailing slash!
2050 \begin_inset LatexCommand \label{sub:Search-Paths}
2055 \begin_inset LatexCommand \index{Search path}
2062 Some search paths or parts of them are determined by configure variables
2067 , see section above).
2068 Further search paths are determined by environment variables during runtime.
2071 The paths searched when running the compiler are as follows (the first catch
2077 Binary files (preprocessor, assembler and linker)
2083 \begin_inset Tabular
2084 <lyxtabular version="3" rows="4" columns="3">
2086 <column alignment="block" valignment="top" leftline="true" width="0in">
2087 <column alignment="block" valignment="top" leftline="true" width="0in">
2088 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
2089 <row topline="true" bottomline="true">
2090 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2098 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2106 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2115 <row topline="true">
2116 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2126 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2134 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2145 <row topline="true">
2146 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2151 Path of argv[0] (if available)
2154 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2162 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2171 <row topline="true" bottomline="true">
2172 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2180 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2188 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2213 \begin_inset Tabular
2214 <lyxtabular version="3" rows="6" columns="3">
2216 <column alignment="block" valignment="top" leftline="true" width="1.5in">
2217 <column alignment="block" valignment="top" leftline="true" width="1.5in">
2218 <column alignment="block" valignment="top" leftline="true" rightline="true" width="0in">
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2220 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2228 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2236 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2245 <row topline="true">
2246 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2264 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2282 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2301 <row topline="true">
2302 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2310 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2318 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2327 <row topline="true">
2328 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2342 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2354 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2365 <row topline="true">
2366 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2384 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2434 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2447 <row topline="true" bottomline="true">
2448 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2464 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2469 /usr/local/share/sdcc/
2474 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2502 -nostdinc disables the last two search paths.
2512 With the exception of
2513 \begin_inset Quotes sld
2527 \begin_inset Quotes srd
2534 is auto-appended by the compiler (e.g.
2535 small, large, z80, ds390 etc.).
2542 \begin_inset Tabular
2543 <lyxtabular version="3" rows="6" columns="3">
2545 <column alignment="block" valignment="top" leftline="true" width="1.7in">
2546 <column alignment="block" valignment="top" leftline="true" width="1.2in">
2547 <column alignment="block" valignment="top" leftline="true" rightline="true" width="1.2in">
2548 <row topline="true" bottomline="true">
2549 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2557 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2565 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2574 <row topline="true">
2575 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2593 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2611 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2630 <row topline="true">
2631 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2643 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2655 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2670 <row topline="true">
2671 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2682 $LIB_DIR_SUFFIX/<model>
2685 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2699 <cell alignment="left" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2716 <row topline="true">
2717 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2732 $LIB_DIR_SUFFIX/<model>
2735 <cell alignment="left" valignment="top" topline="true" leftline="true" usebox="none">
2788 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2844 <row topline="true" bottomline="true">
2845 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2854 $LIB_DIR_SUFFIX/<model>
2857 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
2862 /usr/local/share/sdcc/
2869 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
2887 Don't delete any of the stray spaces in the table above without checking
2888 the HTML output (last line)!
2904 -nostdlib disables the last two search paths.
2908 \begin_inset LatexCommand \index{Building SDCC}
2915 Building SDCC on Linux
2916 \begin_inset LatexCommand \label{sub:Building-SDCC-on-Linux}
2925 Download the source package
2927 either from the SDCC CVS repository or from the nightly snapshots
2929 , it will be named something like sdcc
2940 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
2949 Bring up a command line terminal, such as xterm.
2954 Unpack the file using a command like:
2957 "tar -xvzf sdcc.src.tar.gz
2962 , this will create a sub-directory called sdcc with all of the sources.
2965 Change directory into the main SDCC directory, for example type:
2982 This configures the package for compilation on your system.
2998 All of the source packages will compile, this can take a while.
3014 This copies the binary executables, the include files, the libraries and
3015 the documentation to the install directories.
3016 Proceed with section
3017 \begin_inset LatexCommand \ref{sec:Testing-the-SDCC}
3024 Building SDCC on OSX 2.x
3027 Follow the instruction for Linux.
3031 On OSX 2.x it was reported, that the default gcc (version 3.1 20020420 (prerelease
3032 )) fails to compile SDCC.
3033 Fortunately there's also gcc 2.9.x installed, which works fine.
3034 This compiler can be selected by running 'configure' with:
3037 ./configure CC=gcc2 CXX=g++2
3040 Cross compiling SDCC on Linux for Windows
3043 With the Mingw32 gcc cross compiler it's easy to compile SDCC for Win32.
3044 See section 'Configure Options'.
3047 Building SDCC on Windows
3050 With the exception of Cygwin the SDCC binaries uCsim and sdcdb can't be
3052 They use Unix-sockets, which are not available on Win32.
3055 Building SDCC using Cygwin and Mingw32
3058 For building and installing a Cygwin executable follow the instructions
3064 \begin_inset Quotes sld
3068 \begin_inset Quotes srd
3071 Win32-binary can be built, which will not need the Cygwin-DLL.
3072 For the necessary 'configure' options see section 'configure options' or
3073 the script 'sdcc/support/scripts/sdcc_cygwin_mingw32'.
3077 In order to install Cygwin on Windows download setup.exe from
3078 \begin_inset LatexCommand \url[www.cygwin.com]{http://www.cygwin.com/}
3084 \begin_inset Quotes sld
3087 default text file type
3088 \begin_inset Quotes srd
3092 \begin_inset Quotes sld
3096 \begin_inset Quotes srd
3099 and download/install at least the following packages.
3100 Some packages are selected by default, others will be automatically selected
3101 because of dependencies with the manually selected packages.
3102 Never deselect these packages!
3111 gcc ; version 3.x is fine, no need to use the old 2.9x
3114 binutils ; selected with gcc
3120 rxvt ; a nice console, which makes life much easier under windoze (see below)
3123 man ; not really needed for building SDCC, but you'll miss it sooner or
3127 less ; not really needed for building SDCC, but you'll miss it sooner or
3131 cvs ; only if you use CVS access
3134 If you want to develop something you'll need:
3137 python ; for the regression tests
3140 gdb ; the gnu debugger, together with the nice GUI
3141 \begin_inset Quotes sld
3145 \begin_inset Quotes srd
3151 openssh ; to access the CF or commit changes
3154 autoconf and autoconf-devel ; if you want to fight with 'configure', don't
3155 use autoconf-stable!
3158 rxvt is a nice console with history.
3159 Replace in your cygwin.bat the line
3178 rxvt -sl 1000 -fn "Lucida Console-12" -sr -cr red
3181 -bg black -fg white -geometry 100x65 -e bash -
3194 Text selected with the mouse is automatically copied to the clipboard, pasting
3195 works with shift-insert.
3199 The other good tip is to make sure you have no //c/-style paths anywhere,
3200 use /cygdrive/c/ instead.
3201 Using // invokes a network lookup which is very slow.
3203 \begin_inset Quotes sld
3207 \begin_inset Quotes srd
3210 is too long, you can change it with e.g.
3216 SDCC sources use the unix line ending LF.
3217 Life is much easier, if you store the source tree on a drive which is mounted
3219 And use an editor which can handle LF-only line endings.
3220 Make sure not to commit files with windows line endings.
3221 The tabulator spacing
3222 \begin_inset LatexCommand \index{tabulator spacing (8 columns)}
3226 used in the project is 8.
3227 Although a tabulator spacing of 8 is a sensible choice for programmers
3228 (it's a power of 2 and allows to display 8/16 bit signed variables without
3229 loosing columns) the plan is to move towards using only spaces in the source.
3232 Building SDCC Using Microsoft Visual C++ 6.0/NET (MSVC)
3237 Download the source package
3239 either from the SDCC CVS repository or from the
3240 \begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
3246 , it will be named something like sdcc
3253 SDCC is distributed with all the projects, workspaces, and files you need
3254 to build it using Visual C++ 6.0/NET (except for sdcdb.exe which currently
3255 doesn't build under MSVC).
3256 The workspace name is 'sdcc.dsw'.
3257 Please note that as it is now, all the executables are created in a folder
3261 Once built you need to copy the executables from sdcc
3265 bin before running SDCC.
3270 WARNING: Visual studio is very picky with line terminations; it expects
3271 the 0x0d, 0x0a DOS style line endings, not the 0x0a Unix style line endings.
3272 When using the CVS repository it's easiest to configure the cvs client
3273 to convert automatically for you.
3274 If however you are getting a message such as "This makefile was not generated
3275 by Developer Studio etc.
3277 \begin_inset Quotes srd
3280 when opening the sdcc.dsw workspace or any of the *.dsp projects, then you
3281 need to convert the Unix style line endings to DOS style line endings.
3282 To do so you can use the
3283 \begin_inset Quotes sld
3287 \begin_inset Quotes srd
3290 utility freely available on the internet.
3291 Doug Hawkins reported in the sdcc-user list that this works:
3299 SDCC> unix2dos sdcc.dsw
3305 SDCC> for /R %I in (*.dsp) do @unix2dos "%I"
3309 In order to build SDCC with MSVC you need win32 executables of bison.exe,
3310 flex.exe, and gawk.exe.
3311 One good place to get them is
3312 \begin_inset LatexCommand \url[here]{http://unxutils.sourceforge.net}
3320 Download the file UnxUtils
3321 \begin_inset LatexCommand \index{UnxUtils}
3326 Now you have to install the utilities and setup MSVC so it can locate the
3328 Here there are two alternatives (choose one!):
3335 a) Extract UnxUtils.zip to your C:
3337 hard disk PRESERVING the original paths, otherwise bison won't work.
3338 (If you are using WinZip make certain that 'Use folder names' is selected)
3342 b) In the Visual C++ IDE click Tools, Options, select the Directory tab,
3343 in 'Show directories for:' select 'Executable files', and in the directories
3344 window add a new path: 'C:
3354 (As a side effect, you get a bunch of Unix utilities that could be useful,
3355 such as diff and patch.)
3362 This one avoids extracting a bunch of files you may not use, but requires
3367 a) Create a directory were to put the tools needed, or use a directory already
3375 b) Extract 'bison.exe', 'bison.hairy', 'bison.simple', 'flex.exe', and gawk.exe
3376 to such directory WITHOUT preserving the original paths.
3377 (If you are using WinZip make certain that 'Use folder names' is not selected)
3381 c) Rename bison.exe to '_bison.exe'.
3385 d) Create a batch file 'bison.bat' in 'C:
3389 ' and add these lines:
3409 _bison %1 %2 %3 %4 %5 %6 %7 %8 %9
3413 Steps 'c' and 'd' are needed because bison requires by default that the
3414 files 'bison.simple' and 'bison.hairy' reside in some weird Unix directory,
3415 '/usr/local/share/' I think.
3416 So it is necessary to tell bison where those files are located if they
3417 are not in such directory.
3418 That is the function of the environment variables BISON_SIMPLE and BISON_HAIRY.
3422 e) In the Visual C++ IDE click Tools, Options, select the Directory tab,
3423 in 'Show directories for:' select 'Executable files', and in the directories
3424 window add a new path: 'c:
3427 Note that you can use any other path instead of 'c:
3429 util', even the path where the Visual C++ tools are, probably: 'C:
3433 Microsoft Visual Studio
3438 So you don't have to execute step 'e' :)
3442 Open 'sdcc.dsw' in Visual Studio, click 'build all', when it finishes copy
3443 the executables from sdcc
3447 bin, and you can compile using SDCC.
3450 Building SDCC Using Borland
3453 From the sdcc directory, run the command "make -f Makefile.bcc".
3454 This should regenerate all the .exe files in the bin directory except for
3455 sdcdb.exe (which currently doesn't build under Borland C++).
3458 If you modify any source files and need to rebuild, be aware that the dependenci
3459 es may not be correctly calculated.
3460 The safest option is to delete all .obj files and run the build again.
3461 From a Cygwin BASH prompt, this can easily be done with the command (be
3462 sure you are in the sdcc directory):
3472 ( -name '*.obj' -o -name '*.lib' -o -name '*.rul'
3474 ) -print -exec rm {}
3483 or on Windows NT/2000/XP from the command prompt with the command:
3490 del /s *.obj *.lib *.rul
3493 from the sdcc directory.
3496 Windows Install Using a ZIP Package
3499 Download the binary zip package from
3500 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
3504 and unpack it using your favorite unpacking tool (gunzip, WinZip, etc).
3505 This should unpack to a group of sub-directories.
3506 An example directory structure after unpacking the mingw32 package is:
3511 bin for the executables, c:
3519 lib for the include and libraries.
3522 Adjust your environment variable PATH to include the location of the bin
3523 directory or start sdcc using the full path.
3526 Windows Install Using the Setup Program
3527 \begin_inset LatexCommand \label{sub:Windows-Install}
3534 Download the setup program
3536 sdcc-x.y.z-setup.exe
3538 for an official release from
3541 \begin_inset LatexCommand \url{http://sf.net/project/showfiles.php?group_id=599}
3545 or a setup program for one of the snapshots
3547 sdcc_yyyymmdd_setup.exe
3550 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
3555 A windows typical installer will guide you through the installation process.
3558 Building the Documentation
3561 If the necessary tools (LyX, LaTeX, LaTeX2HTML) are installed it is as easy
3562 as changing into the doc directory and typing
3566 \begin_inset Quotes srd
3570 \begin_inset Quotes srd
3577 You're invited to make changes and additions to this manual (sdcc/doc/sdccman.ly
3580 \begin_inset LatexCommand \url{http://www.lyx.org}
3584 as editor this is straightforward.
3585 Prebuilt documentation in html and pdf format is available from
3586 \begin_inset LatexCommand \url{http://sdcc.sf.net/snap.php}
3593 Reading the Documentation
3596 Currently reading the document in pdf format is recommended, as for unknown
3597 reason the hyperlinks are working there whereas in the html version they
3604 If you should know why please drop us a note
3610 You'll find the pdf version
3611 \begin_inset LatexCommand \index{PDF version of this document}
3616 \begin_inset LatexCommand \url{http://sdcc.sf.net/doc/sdccman.pdf}
3624 \begin_inset LatexCommand \index{HTML version of this document}
3629 \begin_inset LatexCommand \url{http://sdcc.sf.net/doc/sdccman.html/index.html}
3635 This documentation is in some aspects different from a commercial documentation:
3639 It tries to document SDCC for several processor architectures in one document
3640 (commercially these probably would be separate documents/products).
3642 \begin_inset LatexCommand \index{Status of documentation}
3646 currently matches SDCC for mcs51 and DS390 best and does give too few informati
3648 Z80, PIC14, PIC16 and HC08.
3651 There are many references pointing away from this documentation.
3652 Don't let this distract you.
3654 was a reference like
3655 \begin_inset LatexCommand \url{http://www.opencores.org}
3659 together with a statement
3660 \begin_inset Quotes sld
3663 some processors which are targetted by SDCC can be implemented in a
3680 \begin_inset LatexCommand \index{fpga (field programmable gate array)}
3685 \begin_inset Quotes srd
3688 we expect you to have a quick look there and come back.
3689 If you read this you are on the right track.
3692 Some sections attribute more space to problems, restrictions and warnings
3693 than to the solution.
3696 The installation section and the section about the debugger is intimidating.
3699 There are still lots of typos and there are more different writing styles
3703 Testing the SDCC Compiler
3704 \begin_inset LatexCommand \label{sec:Testing-the-SDCC}
3711 The first thing you should do after installing your SDCC compiler is to
3727 \begin_inset LatexCommand \index{version}
3734 at the prompt, and the program should run and tell you the version.
3735 If it doesn't run, or gives a message about not finding sdcc program, then
3736 you need to check over your installation.
3737 Make sure that the sdcc bin directory is in your executable search path
3738 defined by the PATH environment setting (
3743 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
3750 Install trouble-shooting for suggestions
3753 Make sure that the sdcc program is in the bin folder, if not perhaps something
3754 did not install correctly.
3762 is commonly installed as described in section
3763 \begin_inset Quotes sld
3766 Install and search paths
3767 \begin_inset Quotes srd
3776 Make sure the compiler works on a very simple example.
3777 Type in the following test.c program using your favorite
3803 Compile this using the following command:
3812 If all goes well, the compiler will generate a test.asm and test.rel file.
3813 Congratulations, you've just compiled your first program with SDCC.
3814 We used the -c option to tell SDCC not to link the generated code, just
3815 to keep things simple for this step.
3823 The next step is to try it with the linker.
3833 If all goes well the compiler will link with the libraries and produce
3834 a test.ihx output file.
3839 (no test.ihx, and the linker generates warnings), then the problem is most
3848 usr/local/share/sdcc/lib directory
3855 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
3862 Install trouble-shooting for suggestions).
3870 The final test is to ensure
3878 header files and libraries.
3879 Edit test.c and change it to the following:
3896 strcpy(str1, "testing");
3903 Compile this by typing
3910 This should generate a test.ihx output file, and it should give no warnings
3911 such as not finding the string.h file.
3912 If it cannot find the string.h file, then the problem is that
3916 cannot find the /usr/local/share/sdcc/include directory
3923 \begin_inset LatexCommand \ref{sub:Install-Trouble-shooting}
3930 Install trouble-shooting section for suggestions).
3948 \begin_inset LatexCommand \index{-\/-print-search-dirs}
3952 to find exactly where SDCC is looking for the include and lib files.
3955 Install Trouble-shooting
3956 \begin_inset LatexCommand \label{sub:Install-Trouble-shooting}
3961 \begin_inset LatexCommand \index{Install trouble-shooting}
3968 If SDCC does not build correctly
3971 A thing to try is starting from scratch by unpacking the .tgz source package
3972 again in an empty directory.
3980 ./configure 2>&1 | tee configure.log
3994 make 2>&1 | tee make.log
4001 If anything goes wrong, you can review the log files to locate the problem.
4002 Or a relevant part of this can be attached to an email that could be helpful
4003 when requesting help from the mailing list.
4007 \begin_inset Quotes sld
4011 \begin_inset Quotes srd
4018 \begin_inset Quotes sld
4022 \begin_inset Quotes srd
4025 command is a script that analyzes your system and performs some configuration
4026 to ensure the source package compiles on your system.
4027 It will take a few minutes to run, and will compile a few tests to determine
4028 what compiler features are installed.
4032 \begin_inset Quotes sld
4036 \begin_inset Quotes srd
4042 This runs the GNU make tool, which automatically compiles all the source
4043 packages into the final installed binary executables.
4047 \begin_inset Quotes sld
4051 \begin_inset Quotes erd
4057 This will install the compiler, other executables libraries and include
4058 files into the appropriate directories.
4060 \begin_inset LatexCommand \ref{sub:Install-paths}
4066 \begin_inset LatexCommand \ref{sub:Search-Paths}
4071 about install and search paths.
4073 On most systems you will need super-user privileges to do this.
4079 SDCC is not just a compiler, but a collection of tools by various developers.
4080 These include linkers, assemblers, simulators and other components.
4081 Here is a summary of some of the components.
4082 Note that the included simulator and assembler have separate documentation
4083 which you can find in the source package in their respective directories.
4084 As SDCC grows to include support for other processors, other packages from
4085 various developers are included and may have their own sets of documentation.
4089 You might want to look at the files which are installed in <installdir>.
4090 At the time of this writing, we find the following programs for gcc-builds:
4094 In <installdir>/bin:
4097 sdcc - The compiler.
4100 sdcpp - The C preprocessor.
4103 asx8051 - The assembler for 8051 type processors.
4110 as-gbz80 - The Z80 and GameBoy Z80 assemblers.
4113 aslink -The linker for 8051 type processors.
4120 link-gbz80 - The Z80 and GameBoy Z80 linkers.
4123 s51 - The ucSim 8051 simulator.
4124 Not available on Win32 platforms.
4127 sdcdb - The source debugger.
4128 Not available on Win32 platforms.
4131 packihx - A tool to pack (compress) Intel hex files.
4134 In <installdir>/share/sdcc/include
4140 In <installdir>/share/sdcc/lib
4143 the subdirs src and small, large, z80, gbz80 and ds390 with the precompiled
4147 In <installdir>/share/sdcc/doc
4153 As development for other processors proceeds, this list will expand to include
4154 executables to support processors like AVR, PIC, etc.
4160 This is the actual compiler, it in turn uses the c-preprocessor and invokes
4161 the assembler and linkage editor.
4164 sdcpp - The C-Preprocessor
4168 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
4172 is a modified version of the GNU preprocessor.
4173 The C preprocessor is used to pull in #include sources, process #ifdef
4174 statements, #defines and so on.
4185 - The Assemblers and Linkage Editors
4188 This is retargettable assembler & linkage editor, it was developed by Alan
4190 John Hartman created the version for 8051, and I (Sandeep) have made some
4191 enhancements and bug fixes for it to work properly with SDCC.
4198 \begin_inset LatexCommand \index{s51}
4202 is a freeware, opensource simulator developed by Daniel Drotos.
4203 The simulator is built as part of the build process.
4204 For more information visit Daniel's web site at:
4205 \begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
4210 It currently supports the core mcs51, the Dallas DS80C390 and the Phillips
4212 S51 is currently not available on Win32 platfors.
4215 sdcdb - Source Level Debugger
4219 \begin_inset LatexCommand \index{sdcdb (debugger)}
4223 is the companion source level debugger.
4224 More about sdcdb in section
4225 \begin_inset LatexCommand \ref{cha:Debugging-with-SDCDB}
4230 The current version of the debugger uses Daniel's Simulator S51
4231 \begin_inset LatexCommand \index{s51}
4235 , but can be easily changed to use other simulators.
4236 Sdcdb is currently not available on Win32 platfors.
4245 Single Source File Projects
4248 For single source file 8051 projects the process is very simple.
4249 Compile your programs with the following command
4252 "sdcc sourcefile.c".
4256 This will compile, assemble and link your source file.
4257 Output files are as follows:
4261 \begin_inset LatexCommand \index{<file>.asm}
4266 \begin_inset LatexCommand \index{Assembler source}
4270 file created by the compiler
4274 \begin_inset LatexCommand \index{<file>.lst}
4279 \begin_inset LatexCommand \index{Assembler listing}
4283 file created by the Assembler
4287 \begin_inset LatexCommand \index{<file>.rst}
4292 \begin_inset LatexCommand \index{Assembler listing}
4296 file updated with linkedit information, created by linkage editor
4300 \begin_inset LatexCommand \index{<file>.sym}
4305 \begin_inset LatexCommand \index{Symbol listing}
4309 for the sourcefile, created by the assembler
4313 \begin_inset LatexCommand \index{<file>.rel}
4318 \begin_inset LatexCommand \index{<file>.o}
4323 \begin_inset LatexCommand \index{Object file}
4327 created by the assembler, input to Linkage editor
4331 \begin_inset LatexCommand \index{<file>.map}
4336 \begin_inset LatexCommand \index{Memory map}
4340 for the load module, created by the Linker
4344 \begin_inset LatexCommand \index{<file>.mem}
4348 - A file with a summary of the memory usage
4352 \begin_inset LatexCommand \index{<file>.ihx}
4356 - The load module in Intel hex format
4357 \begin_inset LatexCommand \index{Intel hex format}
4361 (you can select the Motorola S19 format
4362 \begin_inset LatexCommand \index{Motorola S19 format}
4377 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
4382 If you need another format you might want to use
4389 \begin_inset LatexCommand \index{objdump (tool)}
4400 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
4405 Both formats are documented in the documentation of srecord
4406 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
4414 \begin_inset LatexCommand \index{<file>.adb}
4418 - An intermediate file containing debug information needed to create the
4430 \begin_inset LatexCommand \index{-\/-debug}
4438 \begin_inset LatexCommand \index{<file>.cdb}
4442 - An optional file (with -
4452 -debug) containing debug information.
4453 The format is documented in cdbfileformat.pdf
4458 \begin_inset LatexCommand \index{<file> (no extension)}
4462 An optional AOMF or AOMF51
4463 \begin_inset LatexCommand \index{AOMF, AOMF51}
4467 file containing debug information (generated with option -
4494 ormat is commonly used by third party tools (debuggers
4495 \begin_inset LatexCommand \index{Debugger}
4499 , simulators, emulators)
4503 \begin_inset LatexCommand \index{<file>.dump*}
4507 - Dump file to debug the compiler it self (generated with option -
4517 -dumpall) (see section
4518 \begin_inset LatexCommand \ref{sub:Intermediate-Dump-Options}
4524 \begin_inset LatexCommand \ref{sub:The-anatomy-of}
4530 \begin_inset Quotes sld
4533 Anatomy of the compiler
4534 \begin_inset Quotes srd
4540 Projects with Multiple Source Files
4543 SDCC can compile only ONE file at a time.
4544 Let us for example assume that you have a project containing the following
4549 foo1.c (contains some functions)
4551 foo2.c (contains some more functions)
4553 foomain.c (contains more functions and the function main)
4561 The first two files will need to be compiled separately with the commands:
4593 Then compile the source file containing the
4598 \begin_inset LatexCommand \index{Linker}
4602 the files together with the following command:
4610 foomain.c\SpecialChar ~
4611 foo1.rel\SpecialChar ~
4616 \begin_inset LatexCommand \index{<file>.rel}
4628 can be separately compiled as well:
4639 sdcc foomain.rel foo1.rel foo2.rel
4646 The file containing the
4661 file specified in the command line, since the linkage editor processes
4662 file in the order they are presented to it.
4663 The linker is invoked from SDCC using a script file with extension .lnk
4664 \begin_inset LatexCommand \index{<file>.lnk}
4669 You can view this file to troubleshoot linking problems such as those arising
4670 from missing libraries.
4673 Projects with Additional Libraries
4674 \begin_inset LatexCommand \index{Libraries}
4681 Some reusable routines may be compiled into a library, see the documentation
4682 for the assembler and linkage editor (which are in <installdir>/share/sdcc/doc)
4686 \begin_inset LatexCommand \index{<file>.lib}
4693 Libraries created in this manner can be included in the command line.
4694 Make sure you include the -L <library-path> option to tell the linker where
4695 to look for these files if they are not in the current directory.
4696 Here is an example, assuming you have the source file
4708 (if that is not the same as your current project):
4715 sdcc foomain.c foolib.lib -L mylib
4726 must be an absolute path name.
4730 The most efficient way to use libraries is to keep separate modules in separate
4732 The lib file now should name all the modules.rel
4733 \begin_inset LatexCommand \index{<file>.rel}
4738 For an example see the standard library file
4742 in the directory <installdir>/share/lib/small.
4745 Using sdcclib to Create and Manage Libraries
4746 \begin_inset LatexCommand \index{sdcclib}
4753 Alternatively, instead of having a .rel file for each entry on the library
4754 file as described in the preceding section, sdcclib can be used to embed
4755 all the modules belonging to such library in the library file itself.
4756 This results in a larger library file, but it greatly reduces the number
4757 of disk files accessed by the linker.
4758 Additionally, the packed library file contains an index of all include
4759 modules and symbols that significantly speeds up the linking process.
4760 To display a list of options supported by sdcclib type:
4769 \begin_inset LatexCommand \index{sdcclib}
4780 To create a new library file, start by compiling all the required modules.
4818 This will create files _divsint.rel, _divuint.rel, _modsint.rel, _moduint.rel,
4820 The next step is to add the .rel files to the library file:
4828 sdcclib libint.lib _divsint.rel
4831 \begin_inset LatexCommand \index{sdcclib}
4841 sdcclib libint.lib _divuint.rel
4847 sdcclib libint.lib _modsint.rel
4853 sdcclib libint.lib _moduint.rel
4859 sdcclib libint.lib _mulint.rel
4866 If the file already exists in the library, it will be replaced.
4867 To see what modules and symbols are included in the library, options -s
4868 and -m are available.
4876 sdcclib -s libint.lib
4879 \begin_inset LatexCommand \index{sdcclib}
4989 If the source files are compiled using -
5000 \begin_inset LatexCommand \index{-\/-debug}
5004 , the corresponding debug information file .adb will be include in the library
5006 The library files created with sdcclib are plain text files, so they can
5007 be viewed with a text editor.
5008 It is not recomended to modify a library file created with sdcclib using
5009 a text editor, as there are file indexes numbers located accross the file
5010 used by the linker to quickly locate the required module to link.
5011 Once a .rel file (as well as a .adb file) is added to a library using sdcclib,
5012 it can be safely deleted, since all the information required for linking
5013 is embedded in the library file itself.
5014 Library files created using sdcclib are used as described in the preceding
5018 Command Line Options
5019 \begin_inset LatexCommand \index{Command Line Options}
5026 Processor Selection Options
5027 \begin_inset LatexCommand \index{Options processor selection}
5032 \begin_inset LatexCommand \index{Processor selection options}
5038 \labelwidthstring 00.00.0000
5043 \begin_inset LatexCommand \index{-mmcs51}
5049 Generate code for the Intel MCS51
5050 \begin_inset LatexCommand \index{MCS51}
5054 family of processors.
5055 This is the default processor target.
5057 \labelwidthstring 00.00.0000
5062 \begin_inset LatexCommand \index{-mds390}
5068 Generate code for the Dallas DS80C390
5069 \begin_inset LatexCommand \index{DS80C390}
5075 \labelwidthstring 00.00.0000
5080 \begin_inset LatexCommand \index{-mds400}
5086 Generate code for the Dallas DS80C400
5087 \begin_inset LatexCommand \index{DS80C400}
5093 \labelwidthstring 00.00.0000
5098 \begin_inset LatexCommand \index{-mhc08}
5104 Generate code for the Freescale/Motorola HC08
5105 \begin_inset LatexCommand \index{HC08}
5109 family of processors.
5111 \labelwidthstring 00.00.0000
5116 \begin_inset LatexCommand \index{-mz80}
5122 Generate code for the Zilog Z80
5123 \begin_inset LatexCommand \index{Z80}
5127 family of processors.
5129 \labelwidthstring 00.00.0000
5134 \begin_inset LatexCommand \index{-mgbz80}
5140 Generate code for the GameBoy Z80
5141 \begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
5145 processor (Not actively maintained).
5147 \labelwidthstring 00.00.0000
5152 \begin_inset LatexCommand \index{-mavr}
5158 Generate code for the Atmel AVR
5159 \begin_inset LatexCommand \index{AVR}
5163 processor (In development, not complete).
5164 AVR users should probably have a look at winavr
5165 \begin_inset LatexCommand \url{http://sourceforge.net/projects/winavr}
5170 \begin_inset LatexCommand \url{http://www.avrfreaks.net/index.php?name=PNphpBB2&file=index}
5177 I think it is fair to direct users there for now.
5178 Open source is also about avoiding unnecessary work .
5179 But I didn't find the 'official' link.
5181 \labelwidthstring 00.00.0000
5186 \begin_inset LatexCommand \index{-mpic14}
5192 Generate code for the Microchip PIC 14
5193 \begin_inset LatexCommand \index{PIC14}
5197 -bit processors (p16f84 and variants.
5198 In development, not complete).
5201 p16f627 p16f628 p16f84 p16f873 p16f877?
5203 \labelwidthstring 00.00.0000
5208 \begin_inset LatexCommand \index{-mpic16}
5214 Generate code for the Microchip PIC 16
5215 \begin_inset LatexCommand \index{PIC16}
5219 -bit processors (p18f452 and variants.
5220 In development, not complete).
5222 \labelwidthstring 00.00.0000
5228 Generate code for the Toshiba TLCS-900H
5229 \begin_inset LatexCommand \index{TLCS-900H}
5233 processor (Not maintained, not complete).
5235 \labelwidthstring 00.00.0000
5240 \begin_inset LatexCommand \index{-mxa51}
5246 Generate code for the Phillips XA51
5247 \begin_inset LatexCommand \index{XA51}
5251 processor (Not maintained, not complete).
5254 Preprocessor Options
5255 \begin_inset LatexCommand \index{Options preprocessor}
5260 \begin_inset LatexCommand \index{Preprocessor options}
5265 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
5271 \labelwidthstring 00.00.0000
5276 \begin_inset LatexCommand \index{-I<path>}
5282 The additional location where the pre processor will look for <..h> or
5283 \begin_inset Quotes eld
5287 \begin_inset Quotes erd
5292 \labelwidthstring 00.00.0000
5297 \begin_inset LatexCommand \index{-D<macro[=value]>}
5303 Command line definition of macros.
5304 Passed to the preprocessor.
5306 \labelwidthstring 00.00.0000
5311 \begin_inset LatexCommand \index{-M}
5317 Tell the preprocessor to output a rule suitable for make describing the
5318 dependencies of each object file.
5319 For each source file, the preprocessor outputs one make-rule whose target
5320 is the object file name for that source file and whose dependencies are
5321 all the files `#include'd in it.
5322 This rule may be a single line or may be continued with `
5324 '-newline if it is long.
5325 The list of rules is printed on standard output instead of the preprocessed
5328 \begin_inset LatexCommand \index{-E}
5334 \labelwidthstring 00.00.0000
5339 \begin_inset LatexCommand \index{-C}
5345 Tell the preprocessor not to discard comments.
5346 Used with the `-E' option.
5348 \labelwidthstring 00.00.0000
5353 \begin_inset LatexCommand \index{-MM}
5364 Like `-M' but the output mentions only the user header files included with
5366 \begin_inset Quotes eld
5370 System header files included with `#include <file>' are omitted.
5372 \labelwidthstring 00.00.0000
5377 \begin_inset LatexCommand \index{-Aquestion(answer)}
5383 Assert the answer answer for question, in case it is tested with a preprocessor
5384 conditional such as `#if #question(answer)'.
5385 `-A-' disables the standard assertions that normally describe the target
5388 \labelwidthstring 00.00.0000
5393 \begin_inset LatexCommand \index{-Umacro}
5399 Undefine macro macro.
5400 `-U' options are evaluated after all `-D' options, but before any `-include'
5401 and `-imacros' options.
5403 \labelwidthstring 00.00.0000
5408 \begin_inset LatexCommand \index{-dM}
5414 Tell the preprocessor to output only a list of the macro definitions that
5415 are in effect at the end of preprocessing.
5416 Used with the `-E' option.
5418 \labelwidthstring 00.00.0000
5423 \begin_inset LatexCommand \index{-dD}
5429 Tell the preprocessor to pass all macro definitions into the output, in
5430 their proper sequence in the rest of the output.
5432 \labelwidthstring 00.00.0000
5437 \begin_inset LatexCommand \index{-dN}
5448 Like `-dD' except that the macro arguments and contents are omitted.
5449 Only `#define name' is included in the output.
5451 \labelwidthstring 00.00.0000
5456 preprocessorOption[,preprocessorOption]
5459 \begin_inset LatexCommand \index{-Wp preprocessorOption[,preprocessorOption]}
5464 Pass the preprocessorOption to the preprocessor
5469 \begin_inset LatexCommand \index{sdcpp (preprocessor)}
5474 SDCC uses an adapted version of the preprocessor cpp of the GNU Compiler
5475 Collection (gcc), if you need more dedicated options please refer to the
5477 \begin_inset LatexCommand \htmlurl{http://www.gnu.org/software/gcc/onlinedocs/}
5485 \begin_inset LatexCommand \index{Options linker}
5490 \begin_inset LatexCommand \index{Linker options}
5496 \labelwidthstring 00.00.0000
5516 \begin_inset LatexCommand \index{-\/-lib-path <path>}
5521 \begin_inset LatexCommand \index{-L -\/-lib-path}
5528 <absolute path to additional libraries> This option is passed to the linkage
5529 editor's additional libraries
5530 \begin_inset LatexCommand \index{Libraries}
5535 The path name must be absolute.
5536 Additional library files may be specified in the command line.
5537 See section Compiling programs for more details.
5539 \labelwidthstring 00.00.0000
5556 \begin_inset LatexCommand \index{-\/-xram-loc <Value>}
5561 <Value> The start location of the external ram
5562 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
5566 , default value is 0.
5567 The value entered can be in Hexadecimal or Decimal format, e.g.: -
5577 -xram-loc 0x8000 or -
5589 \labelwidthstring 00.00.0000
5606 \begin_inset LatexCommand \index{-\/-code-loc <Value>}
5611 <Value> The start location of the code
5612 \begin_inset LatexCommand \index{code}
5616 segment, default value 0.
5617 Note when this option is used the interrupt vector table is also relocated
5618 to the given address.
5619 The value entered can be in Hexadecimal or Decimal format, e.g.: -
5629 -code-loc 0x8000 or -
5641 \labelwidthstring 00.00.0000
5658 \begin_inset LatexCommand \index{-\/-stack-loc <Value>}
5663 <Value> By default the stack
5664 \begin_inset LatexCommand \index{stack}
5668 is placed after the data segment.
5669 Using this option the stack can be placed anywhere in the internal memory
5671 The value entered can be in Hexadecimal or Decimal format, e.g.
5682 -stack-loc 0x20 or -
5693 Since the sp register is incremented before a push or call, the initial
5694 sp will be set to one byte prior the provided value.
5695 The provided value should not overlap any other memory areas such as used
5696 register banks or the data segment and with enough space for the current
5714 \begin_inset LatexCommand \index{-\/-pack-iram}
5718 option (which is now a default setting) will override this setting, so
5719 you should also specify the
5735 \begin_inset LatexCommand \index{-\/-no-pack-iram}
5739 option if you need to manually place the stack.
5741 \labelwidthstring 00.00.0000
5758 \begin_inset LatexCommand \index{-\/-data-loc <Value>}
5763 <Value> The start location of the internal ram data
5764 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
5769 The value entered can be in Hexadecimal or Decimal format, eg.
5791 (By default, the start location of the internal ram data segment is set
5792 as low as possible in memory, taking into account the used register banks
5793 and the bit segment at address 0x20.
5794 For example if register banks 0 and 1 are used without bit variables, the
5795 data segment will be set, if -
5805 -data-loc is not used, to location 0x10.)
5807 \labelwidthstring 00.00.0000
5824 \begin_inset LatexCommand \index{-\/-idata-loc <Value>}
5829 <Value> The start location of the indirectly addressable internal ram
5830 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
5834 of the 8051, default value is 0x80.
5835 The value entered can be in Hexadecimal or Decimal format, eg.
5846 -idata-loc 0x88 or -
5858 \labelwidthstring 00.00.0000
5875 <Value> The start location of the bit
5876 \begin_inset LatexCommand \index{bit}
5880 addressable internal ram of the 8051.
5886 Instead an option can be passed directly to the linker: -Wl\SpecialChar ~
5889 \labelwidthstring 00.00.0000
5904 \begin_inset LatexCommand \index{-\/-out-fmt-ihx}
5913 The linker output (final object code) is in Intel Hex format.
5914 \begin_inset LatexCommand \index{Intel hex format}
5918 This is the default option.
5919 The format itself is documented in the documentation of srecord
5920 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
5926 \labelwidthstring 00.00.0000
5941 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
5950 The linker output (final object code) is in Motorola S19 format
5951 \begin_inset LatexCommand \index{Motorola S19 format}
5956 The format itself is documented in the documentation of srecord.
5958 \labelwidthstring 00.00.0000
5973 \begin_inset LatexCommand \index{-\/-out-fmt-s19}
5982 The linker output (final object code) is in ELF format
5983 \begin_inset LatexCommand \index{ELF format}
5988 (Currently only supported for the HC08 processors)
5990 \labelwidthstring 00.00.0000
5995 linkOption[,linkOption]
5998 \begin_inset LatexCommand \index{-Wl linkOption[,linkOption]}
6003 Pass the linkOption to the linker.
6004 See file sdcc/as/doc/asxhtm.html for more on linker options.
6008 \begin_inset LatexCommand \index{Options MCS51}
6013 \begin_inset LatexCommand \index{MCS51 options}
6019 \labelwidthstring 00.00.0000
6034 \begin_inset LatexCommand \index{-\/-model-small}
6045 Generate code for Small Model programs, see section Memory Models for more
6047 This is the default model.
6049 \labelwidthstring 00.00.0000
6064 \begin_inset LatexCommand \index{-\/-model-medium}
6070 Generate code for Medium model programs, see section Memory Models for
6072 If this option is used all source files in the project have to be compiled
6074 It must also be used when invoking the linker.
6076 \labelwidthstring 00.00.0000
6091 \begin_inset LatexCommand \index{-\/-model-large}
6097 Generate code for Large model programs, see section Memory Models for more
6099 If this option is used all source files in the project have to be compiled
6101 It must also be used when invoking the linker.
6103 \labelwidthstring 00.00.0000
6118 \begin_inset LatexCommand \index{-\/-xstack}
6124 Uses a pseudo stack in the first 256 bytes in the external ram for allocating
6125 variables and passing parameters.
6127 \begin_inset LatexCommand \ref{sub:External-Stack}
6132 External Stack for more details.
6134 \labelwidthstring 00.00.0000
6152 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
6156 Causes the linker to check if the internal ram usage is within limits of
6159 \labelwidthstring 00.00.0000
6177 \begin_inset LatexCommand \index{-\/-xram-size <Value>}
6181 Causes the linker to check if the external ram usage is within limits of
6184 \labelwidthstring 00.00.0000
6202 \begin_inset LatexCommand \index{-\/-code-size <Value>}
6206 Causes the linker to check if the code memory usage is within limits of
6209 \labelwidthstring 00.00.0000
6227 \begin_inset LatexCommand \index{-\/-stack-size <Value>}
6231 Causes the linker to check if there is at minimum <Value> bytes for stack.
6233 \labelwidthstring 00.00.0000
6251 \begin_inset LatexCommand \index{-\/-pack-iram}
6255 Causes the linker to use unused register banks for data variables and pack
6256 data, idata and stack together.
6257 This is the default now.
6259 \labelwidthstring 00.00.0000
6277 \begin_inset LatexCommand \index{-\/-no-pack-iram}
6281 Causes the linker to use old style for allocating memory areas.
6284 DS390 / DS400 Options
6285 \begin_inset LatexCommand \index{Options DS390}
6290 \begin_inset LatexCommand \index{DS390 options}
6296 \labelwidthstring 00.00.0000
6313 \begin_inset LatexCommand \index{-\/-model-flat24}
6323 Generate 24-bit flat mode code.
6324 This is the one and only that the ds390 code generator supports right now
6325 and is default when using
6330 See section Memory Models for more details.
6332 \labelwidthstring 00.00.0000
6347 \begin_inset LatexCommand \index{-\/-protect-sp-update}
6353 disable interrupts during ESP:SP updates.
6355 \labelwidthstring 00.00.0000
6372 \begin_inset LatexCommand \index{-\/-stack-10bit}
6376 Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
6377 This is the one and only that the ds390 code generator supports right now
6378 and is default when using
6383 In this mode, the stack is located in the lower 1K of the internal RAM,
6384 which is mapped to 0x400000.
6385 Note that the support is incomplete, since it still uses a single byte
6386 as the stack pointer.
6387 This means that only the lower 256 bytes of the potential 1K stack space
6388 will actually be used.
6389 However, this does allow you to reclaim the precious 256 bytes of low RAM
6390 for use for the DATA and IDATA segments.
6391 The compiler will not generate any code to put the processor into 10 bit
6393 It is important to ensure that the processor is in this mode before calling
6394 any re-entrant functions compiled with this option.
6395 In principle, this should work with the
6408 \begin_inset LatexCommand \index{-\/-stack-auto}
6414 option, but that has not been tested.
6415 It is incompatible with the
6428 \begin_inset LatexCommand \index{-\/-xstack}
6435 It also only makes sense if the processor is in 24 bit contiguous addressing
6448 -model-flat24 option
6452 \labelwidthstring 00.00.0000
6467 \begin_inset LatexCommand \index{-\/-stack-probe}
6473 insert call to function __stack_probe at each function prologue.
6475 \labelwidthstring 00.00.0000
6490 \begin_inset LatexCommand \index{-\/-tini-libid}
6496 <nnnn> LibraryID used in -mTININative.
6499 \labelwidthstring 00.00.0000
6514 \begin_inset LatexCommand \index{-\/-use-accelerator}
6520 generate code for DS390 Arithmetic Accelerator.
6525 \begin_inset LatexCommand \index{Options Z80}
6530 \begin_inset LatexCommand \index{Z80 options}
6536 \labelwidthstring 00.00.0000
6553 \begin_inset LatexCommand \index{-\/-callee-saves-bc}
6563 Force a called function to always save BC.
6565 \labelwidthstring 00.00.0000
6582 \begin_inset LatexCommand \index{-\/-no-std-crt0}
6586 When linking, skip the standard crt0.o object file.
6587 You must provide your own crt0.o for your system when linking.
6591 Optimization Options
6592 \begin_inset LatexCommand \index{Options optimization}
6597 \begin_inset LatexCommand \index{Optimization options}
6603 \labelwidthstring 00.00.0000
6618 \begin_inset LatexCommand \index{-\/-nogcse}
6624 Will not do global subexpression elimination, this option may be used when
6625 the compiler creates undesirably large stack/data spaces to store compiler
6635 \begin_inset LatexCommand \index{sloc (spill location)}
6640 A warning message will be generated when this happens and the compiler
6641 will indicate the number of extra bytes it allocated.
6642 It is recommended that this option NOT be used, #pragma\SpecialChar ~
6644 \begin_inset LatexCommand \index{\#pragma nogcse}
6648 can be used to turn off global subexpression elimination
6649 \begin_inset LatexCommand \index{Subexpression elimination}
6653 for a given function only.
6655 \labelwidthstring 00.00.0000
6670 \begin_inset LatexCommand \index{-\/-noinvariant}
6676 Will not do loop invariant optimizations, this may be turned off for reasons
6677 explained for the previous option.
6678 For more details of loop optimizations performed see Loop Invariants in
6680 \begin_inset LatexCommand \ref{sub:Loop-Optimizations}
6685 It is recommended that this option NOT be used, #pragma\SpecialChar ~
6687 \begin_inset LatexCommand \index{\#pragma noinvariant}
6691 can be used to turn off invariant optimizations for a given function only.
6693 \labelwidthstring 00.00.0000
6708 \begin_inset LatexCommand \index{-\/-noinduction}
6714 Will not do loop induction optimizations, see section strength reduction
6716 It is recommended that this option is NOT used, #pragma\SpecialChar ~
6718 \begin_inset LatexCommand \index{\#pragma noinduction}
6722 can be used to turn off induction optimizations for a given function only.
6724 \labelwidthstring 00.00.0000
6739 \begin_inset LatexCommand \index{-\/-nojtbound}
6750 Will not generate boundary condition check when switch statements
6751 \begin_inset LatexCommand \index{switch statement}
6755 are implemented using jump-tables.
6757 \begin_inset LatexCommand \ref{sub:'switch'-Statements}
6762 Switch Statements for more details.
6763 It is recommended that this option is NOT used, #pragma\SpecialChar ~
6765 \begin_inset LatexCommand \index{\#pragma nojtbound}
6769 can be used to turn off boundary checking for jump tables for a given function
6772 \labelwidthstring 00.00.0000
6787 \begin_inset LatexCommand \index{-\/-noloopreverse}
6796 Will not do loop reversal
6797 \begin_inset LatexCommand \index{Loop reversing}
6803 \labelwidthstring 00.00.0000
6820 \begin_inset LatexCommand \index{-\/-nolabelopt }
6824 Will not optimize labels (makes the dumpfiles more readable).
6826 \labelwidthstring 00.00.0000
6841 \begin_inset LatexCommand \index{-\/-no-xinit-opt}
6847 Will not memcpy initialized data from code space into xdata space.
6848 This saves a few bytes in code space if you don't have initialized data
6849 \begin_inset LatexCommand \index{Variable initialization}
6855 \labelwidthstring 00.00.0000
6870 \begin_inset LatexCommand \index{-\/-nooverlay}
6876 The compiler will not overlay parameters and local variables of any function,
6877 see section Parameters and local variables for more details.
6879 \labelwidthstring 00.00.0000
6894 \begin_inset LatexCommand \index{-\/-no-peep}
6900 Disable peep-hole optimization.
6902 \labelwidthstring 00.00.0000
6919 \begin_inset LatexCommand \index{-\/-peep-file}
6924 <filename> This option can be used to use additional rules to be used by
6925 the peep hole optimizer.
6927 \begin_inset LatexCommand \ref{sub:Peephole-Optimizer}
6932 Peep Hole optimizations for details on how to write these rules.
6934 \labelwidthstring 00.00.0000
6949 \begin_inset LatexCommand \index{-\/-peep-asm}
6955 Pass the inline assembler code through the peep hole optimizer.
6956 This can cause unexpected changes to inline assembler code, please go through
6957 the peephole optimizer
6958 \begin_inset LatexCommand \index{Peephole optimizer}
6962 rules defined in the source file tree '<target>/peeph.def' before using
6965 \labelwidthstring 00.00.0000
6980 \begin_inset LatexCommand \index{-\/-opt-code-speed}
6986 The compiler will optimize code generation towards fast code, possibly
6987 at the expense of code size.
6989 \labelwidthstring 00.00.0000
7004 \begin_inset LatexCommand \index{-\/-opt-code-size}
7010 The compiler will optimize code generation towards compact code, possibly
7011 at the expense of code speed.
7015 \begin_inset LatexCommand \index{Options other}
7021 \labelwidthstring 00.00.0000
7037 \begin_inset LatexCommand \index{-\/-compile-only}
7042 \begin_inset LatexCommand \index{-c -\/-compile-only}
7048 will compile and assemble the source, but will not call the linkage editor.
7050 \labelwidthstring 00.00.0000
7069 \begin_inset LatexCommand \index{-\/-c1mode}
7075 reads the preprocessed source from standard input and compiles it.
7076 The file name for the assembler output must be specified using the -o option.
7078 \labelwidthstring 00.00.0000
7083 \begin_inset LatexCommand \index{-E}
7089 Run only the C preprocessor.
7090 Preprocess all the C source files specified and output the results to standard
7093 \labelwidthstring 00.00.0000
7099 \begin_inset LatexCommand \index{-o <path/file>}
7105 The output path resp.
7106 file where everything will be placed.
7107 If the parameter is a path, it must have a trailing slash (or backslash
7108 for the Windows binaries) to be recognized as a path.
7111 \labelwidthstring 00.00.0000
7126 \begin_inset LatexCommand \index{-\/-stack-auto}
7137 All functions in the source file will be compiled as
7142 \begin_inset LatexCommand \index{reentrant}
7147 the parameters and local variables will be allocated on the stack
7148 \begin_inset LatexCommand \index{stack}
7154 \begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
7158 Parameters and Local Variables for more details.
7159 If this option is used all source files in the project should be compiled
7161 It automatically implies --int-long-reent and --float-reent.
7164 \labelwidthstring 00.00.0000
7179 \begin_inset LatexCommand \index{-\/-callee-saves}
7183 function1[,function2][,function3]....
7186 The compiler by default uses a caller saves convention for register saving
7187 across function calls, however this can cause unnecessary register pushing
7188 & popping when calling small functions from larger functions.
7189 This option can be used to switch the register saving convention for the
7190 function names specified.
7191 The compiler will not save registers when calling these functions, no extra
7192 code will be generated at the entry & exit (function prologue
7195 \begin_inset LatexCommand \index{function prologue}
7204 \begin_inset LatexCommand \index{function epilogue}
7210 ) for these functions to save & restore the registers used by these functions,
7211 this can SUBSTANTIALLY reduce code & improve run time performance of the
7213 In the future the compiler (with inter procedural analysis) will be able
7214 to determine the appropriate scheme to use for each function call.
7215 DO NOT use this option for built-in functions such as _mulint..., if this
7216 option is used for a library function the appropriate library function
7217 needs to be recompiled with the same option.
7218 If the project consists of multiple source files then all the source file
7219 should be compiled with the same -
7229 -callee-saves option string.
7230 Also see #pragma\SpecialChar ~
7232 \begin_inset LatexCommand \index{\#pragma callee\_saves}
7238 \labelwidthstring 00.00.0000
7253 \begin_inset LatexCommand \index{-\/-debug}
7262 When this option is used the compiler will generate debug information.
7263 The debug information collected in a file with .cdb extension can be used
7265 For more information see documentation for SDCDB.
7266 Another file with no extension contains debug information in AOMF or AOMF51
7267 \begin_inset LatexCommand \index{AOMF, AOMF51}
7271 format which is commonly used by third party tools.
7273 \labelwidthstring 00.00.0000
7278 \begin_inset LatexCommand \index{-S}
7289 Stop after the stage of compilation proper; do not assemble.
7290 The output is an assembler code file for the input file specified.
7292 \labelwidthstring 00.00.0000
7307 \begin_inset LatexCommand \index{-\/-int-long-reent}
7313 Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
7314 Note by default these libraries are compiled as non-reentrant.
7315 See section Installation for more details.
7317 \labelwidthstring 00.00.0000
7332 \begin_inset LatexCommand \index{-\/-cyclomatic}
7341 This option will cause the compiler to generate an information message for
7342 each function in the source file.
7343 The message contains some
7347 information about the function.
7348 The number of edges and nodes the compiler detected in the control flow
7349 graph of the function, and most importantly the
7351 cyclomatic complexity
7352 \begin_inset LatexCommand \index{Cyclomatic complexity}
7358 see section on Cyclomatic Complexity for more details.
7360 \labelwidthstring 00.00.0000
7375 \begin_inset LatexCommand \index{-\/-float-reent}
7381 Floating point library is compiled as reentrant
7382 \begin_inset LatexCommand \index{reentrant}
7387 See section Installation for more details.
7389 \labelwidthstring 00.00.0000
7404 \begin_inset LatexCommand \index{-\/-main-return}
7410 This option can be used if the code generated is called by a monitor program
7411 or if the main routine includes an endless loop.
7412 This option might result in slightly smaller code and save two bytes of
7414 The return from the 'main'
7415 \begin_inset LatexCommand \index{main return}
7419 function will return to the function calling main.
7420 The default setting is to lock up i.e.
7427 \labelwidthstring 00.00.0000
7442 \begin_inset LatexCommand \index{-\/-nostdinc}
7448 This will prevent the compiler from passing on the default include path
7449 to the preprocessor.
7451 \labelwidthstring 00.00.0000
7466 \begin_inset LatexCommand \index{-\/-nostdlib}
7472 This will prevent the compiler from passing on the default library
7473 \begin_inset LatexCommand \index{Libraries}
7479 \labelwidthstring 00.00.0000
7494 \begin_inset LatexCommand \index{-\/-verbose}
7500 Shows the various actions the compiler is performing.
7502 \labelwidthstring 00.00.0000
7507 \begin_inset LatexCommand \index{-V}
7513 Shows the actual commands the compiler is executing.
7515 \labelwidthstring 00.00.0000
7530 \begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
7536 Hides your ugly and inefficient c-code from the asm file, so you can always
7537 blame the compiler :)
7539 \labelwidthstring 00.00.0000
7554 \begin_inset LatexCommand \index{-\/-no-peep-comments}
7560 Will not include peep-hole comments in the generated files.
7562 \labelwidthstring 00.00.0000
7577 \begin_inset LatexCommand \index{-\/-i-code-in-asm}
7583 Include i-codes in the asm file.
7584 Sounds like noise but is most helpful for debugging the compiler itself.
7586 \labelwidthstring 00.00.0000
7601 \begin_inset LatexCommand \index{-\/-less-pedantic}
7607 Disable some of the more pedantic warnings
7608 \begin_inset LatexCommand \index{Warnings}
7612 (jwk burps: please be more specific here, please!).
7614 \labelwidthstring 00.00.0000
7628 -disable-warning\SpecialChar ~
7630 \begin_inset LatexCommand \index{-\/-disable-warning}
7636 Disable specific warning with number <nnnn>.
7638 \labelwidthstring 00.00.0000
7653 \begin_inset LatexCommand \index{-\/-print-search-dirs}
7659 Display the directories in the compiler's search path
7661 \labelwidthstring 00.00.0000
7676 \begin_inset LatexCommand \index{-\/-vc}
7682 Display errors and warnings using MSVC style, so you can use SDCC with
7685 \labelwidthstring 00.00.0000
7700 \begin_inset LatexCommand \index{-\/-use-stdout}
7706 Send errors and warnings to stdout instead of stderr.
7708 \labelwidthstring 00.00.0000
7713 asmOption[,asmOption]
7716 \begin_inset LatexCommand \index{-Wa asmOption[,asmOption]}
7721 Pass the asmOption to the assembler
7722 \begin_inset LatexCommand \index{Options assembler}
7727 \begin_inset LatexCommand \index{Assembler options}
7732 See file sdcc/as/doc/asxhtm.html for assembler options.cd
7734 \labelwidthstring 00.00.0000
7749 \begin_inset LatexCommand \index{-\/-std-sdcc89}
7755 Generally follow the C89 standard, but allow SDCC features that conflict
7756 with the standard (default).
7758 \labelwidthstring 00.00.0000
7773 \begin_inset LatexCommand \index{-\/-std-c89}
7779 Follow the C89 standard and disable SDCC features that conflict with the
7782 \labelwidthstring 00.00.0000
7797 \begin_inset LatexCommand \index{-\/-std-sdcc99}
7803 Generally follow the C99 standard, but allow SDCC features that conflict
7804 with the standard (incomplete support).
7806 \labelwidthstring 00.00.0000
7821 \begin_inset LatexCommand \index{-\/-std-sdcc99}
7827 Follow the C99 standard and disable SDCC features that conflict with the
7828 standard (incomplete support).
7830 \labelwidthstring 00.00.0000
7847 \begin_inset LatexCommand \index{-\/-codeseg <Value>}
7852 <Name> The name to be used for the code
7853 \begin_inset LatexCommand \index{code}
7857 segment, default CSEG.
7858 This is useful if you need to tell the compiler to put the code in a special
7859 segment so you can later on tell the linker to put this segment in a special
7861 Can be used for instance when using bank switching to put the code in a
7864 \labelwidthstring 00.00.0000
7881 \begin_inset LatexCommand \index{-\/-constseg <Value>}
7886 <Name> The name to be used for the const
7887 \begin_inset LatexCommand \index{code}
7891 segment, default CONST.
7892 This is useful if you need to tell the compiler to put the const data in
7893 a special segment so you can later on tell the linker to put this segment
7894 in a special place in memory.
7895 Can be used for instance when using bank switching to put the const data
7898 \labelwidthstring 00.00.0000
7910 a SDCC compiler option but if you want
7914 warnings you can use a separate tool dedicated to syntax checking like
7916 \begin_inset LatexCommand \label{lyx:more-pedantic-SPLINT}
7921 \begin_inset LatexCommand \index{lint (syntax checking tool)}
7926 \begin_inset LatexCommand \url{http://www.splint.org}
7931 To make your source files parseable by splint you will have to include
7937 \begin_inset LatexCommand \index{splint (syntax checking tool)}
7941 in your source file and add brackets around extended keywords (like
7944 \begin_inset Quotes sld
7957 \begin_inset Quotes srd
7965 \begin_inset Quotes sld
7968 __interrupt\SpecialChar ~
7970 \begin_inset Quotes srd
7978 Splint has an excellent on line manual at
7979 \begin_inset LatexCommand \url{http://www.splint.org/manual/}
7983 and it's capabilities go beyond pure syntax checking.
7984 You'll need to tell splint the location of SDCC's include files so a typical
7985 command line could look like this:
7989 splint\SpecialChar ~
7991 /usr/local/share/sdcc/include/mcs51/\SpecialChar ~
7996 Intermediate Dump Options
7997 \begin_inset LatexCommand \label{sub:Intermediate-Dump-Options}
8002 \begin_inset LatexCommand \index{Options intermediate dump}
8007 \begin_inset LatexCommand \index{Intermediate dump options}
8014 The following options are provided for the purpose of retargetting and debugging
8016 They provide a means to dump the intermediate code (iCode
8017 \begin_inset LatexCommand \index{iCode}
8021 ) generated by the compiler in human readable form at various stages of
8022 the compilation process.
8023 More on iCodes see chapter
8024 \begin_inset LatexCommand \ref{sub:The-anatomy-of}
8029 \begin_inset Quotes srd
8032 The anatomy of the compiler
8033 \begin_inset Quotes srd
8038 \labelwidthstring 00.00.0000
8053 \begin_inset LatexCommand \index{-\/-dumpraw}
8059 This option will cause the compiler to dump the intermediate code into
8062 <source filename>.dumpraw
8064 just after the intermediate code has been generated for a function, i.e.
8065 before any optimizations are done.
8067 \begin_inset LatexCommand \index{Basic blocks}
8071 at this stage ordered in the depth first number, so they may not be in
8072 sequence of execution.
8074 \labelwidthstring 00.00.0000
8089 \begin_inset LatexCommand \index{-\/-dumpgcse}
8095 Will create a dump of iCode's, after global subexpression elimination
8096 \begin_inset LatexCommand \index{Global subexpression elimination}
8102 <source filename>.dumpgcse.
8104 \labelwidthstring 00.00.0000
8119 \begin_inset LatexCommand \index{-\/-dumpdeadcode}
8125 Will create a dump of iCode's, after deadcode elimination
8126 \begin_inset LatexCommand \index{Dead-code elimination}
8132 <source filename>.dumpdeadcode.
8134 \labelwidthstring 00.00.0000
8149 \begin_inset LatexCommand \index{-\/-dumploop}
8158 Will create a dump of iCode's, after loop optimizations
8159 \begin_inset LatexCommand \index{Loop optimization}
8165 <source filename>.dumploop.
8167 \labelwidthstring 00.00.0000
8182 \begin_inset LatexCommand \index{-\/-dumprange}
8191 Will create a dump of iCode's, after live range analysis
8192 \begin_inset LatexCommand \index{Live range analysis}
8198 <source filename>.dumprange.
8200 \labelwidthstring 00.00.0000
8215 \begin_inset LatexCommand \index{-\/-dumlrange}
8221 Will dump the life ranges
8222 \begin_inset LatexCommand \index{Live range analysis}
8228 \labelwidthstring 00.00.0000
8243 \begin_inset LatexCommand \index{-\/-dumpregassign}
8252 Will create a dump of iCode's, after register assignment
8253 \begin_inset LatexCommand \index{Register assignment}
8259 <source filename>.dumprassgn.
8261 \labelwidthstring 00.00.0000
8276 \begin_inset LatexCommand \index{-\/-dumplrange}
8282 Will create a dump of the live ranges of iTemp's
8284 \labelwidthstring 00.00.0000
8299 \begin_inset LatexCommand \index{-\/-dumpall}
8310 Will cause all the above mentioned dumps to be created.
8313 Redirecting output on Windows Shells
8316 By default SDCC writes it's error messages to
8317 \begin_inset Quotes sld
8321 \begin_inset Quotes srd
8325 To force all messages to
8326 \begin_inset Quotes sld
8330 \begin_inset Quotes srd
8354 \begin_inset LatexCommand \index{-\/-use-stdout}
8359 Additionally, if you happen to have visual studio installed in your windows
8360 machine, you can use it to compile your sources using a custom build and
8376 \begin_inset LatexCommand \index{-\/-vc}
8381 Something like this should work:
8425 -model-large -c $(InputPath)
8428 Environment variables
8429 \begin_inset LatexCommand \index{Environment variables}
8436 SDCC recognizes the following environment variables:
8438 \labelwidthstring 00.00.0000
8443 \begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
8449 SDCC installs a signal handler
8450 \begin_inset LatexCommand \index{signal handler}
8454 to be able to delete temporary files after an user break (^C) or an exception.
8455 If this environment variable is set, SDCC won't install the signal handler
8456 in order to be able to debug SDCC.
8458 \labelwidthstring 00.00.0000
8465 \begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}
8471 Path, where temporary files will be created.
8472 The order of the variables is the search order.
8473 In a standard *nix environment these variables are not set, and there's
8474 no need to set them.
8475 On Windows it's recommended to set one of them.
8477 \labelwidthstring 00.00.0000
8482 \begin_inset LatexCommand \index{SDCC\_HOME}
8489 \begin_inset LatexCommand \ref{sub:Install-paths}
8495 \begin_inset Quotes sld
8499 \begin_inset Quotes srd
8504 \labelwidthstring 00.00.0000
8509 \begin_inset LatexCommand \index{SDCC\_INCLUDE}
8516 \begin_inset LatexCommand \ref{sub:Search-Paths}
8522 \begin_inset Quotes sld
8526 \begin_inset Quotes srd
8531 \labelwidthstring 00.00.0000
8536 \begin_inset LatexCommand \index{SDCC\_LIB}
8543 \begin_inset LatexCommand \ref{sub:Search-Paths}
8549 \begin_inset Quotes sld
8553 \begin_inset Quotes srd
8559 There are some more environment variables recognized by SDCC, but these
8560 are solely used for debugging purposes.
8561 They can change or disappear very quickly, and will never be documented.
8564 Storage Class Language Extensions
8567 MCS51/DS390 Storage Class
8568 \begin_inset LatexCommand \index{Storage class}
8575 In addition to the ANSI storage classes SDCC allows the following MCS51
8576 specific storage classes:
8577 \layout Subsubsection
8580 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
8585 \begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
8590 \begin_inset LatexCommand \index{near (storage class)}
8595 \begin_inset LatexCommand \index{\_\_near (storage class)}
8606 storage class for the Small Memory model (
8614 can be used synonymously).
8615 Variables declared with this storage class will be allocated in the directly
8616 addressable portion of the internal RAM of a 8051, e.g.:
8621 data unsigned char test_data;
8624 Writing 0x01 to this variable generates the assembly code:
8629 75*00 01\SpecialChar ~
8635 \layout Subsubsection
8638 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
8643 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
8648 \begin_inset LatexCommand \index{far (storage class)}
8653 \begin_inset LatexCommand \index{\_\_far (storage class)}
8660 Variables declared with this storage class will be placed in the external
8666 storage class for the Large Memory model, e.g.:
8671 xdata unsigned char test_xdata;
8674 Writing 0x01 to this variable generates the assembly code:
8679 90s00r00\SpecialChar ~
8708 \layout Subsubsection
8711 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
8716 \begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
8723 Variables declared with this storage class will be allocated into the indirectly
8724 addressable portion of the internal ram of a 8051, e.g.:
8729 idata unsigned char test_idata;
8732 Writing 0x01 to this variable generates the assembly code:
8761 Please note, the first 128 byte of idata physically access the same RAM
8763 The original 8051 had 128 byte idata memory, nowadays most devices have
8764 256 byte idata memory.
8766 \begin_inset LatexCommand \index{stack}
8770 is located in idata memory.
8771 \layout Subsubsection
8774 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
8779 \begin_inset LatexCommand \index{\_\_pdata (mcs51, ds390 storage class)}
8786 Paged xdata access is just as straightforward as using the other addressing
8788 It is typically located at the start of xdata and has a maximum size of
8790 The following example writes 0x01 to the pdata variable.
8791 Please note, pdata access physically accesses xdata memory.
8792 The high byte of the address is determined by port P2
8793 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
8797 (or in case of some 8051 variants by a separate Special Function Register,
8799 \begin_inset LatexCommand \ref{sub:MCS51-variants}
8808 storage class for the Medium Memory model, e.g.:
8813 pdata unsigned char test_pdata;
8816 Writing 0x01 to this variable generates the assembly code:
8860 \begin_inset LatexCommand \index{-\/-xstack}
8864 option is used the pdata memory area is followed by the xstack memory area
8865 and the sum of their sizes is limited to 256 bytes.
8866 \layout Subsubsection
8869 \begin_inset LatexCommand \index{code}
8874 \begin_inset LatexCommand \index{\_\_code}
8881 'Variables' declared with this storage class will be placed in the code
8887 code unsigned char test_code;
8890 Read access to this variable generates the assembly code:
8895 90s00r6F\SpecialChar ~
8898 mov dptr,#_test_code
8927 indexed arrays of characters in code memory can be accessed efficiently:
8932 code char test_array[] = {'c','h','e','a','p'};
8935 Read access to this array using an 8-bit unsigned index generates the assembly
8952 90s00r41\SpecialChar ~
8955 mov dptr,#_test_array
8970 \layout Subsubsection
8973 \begin_inset LatexCommand \index{bit}
8978 \begin_inset LatexCommand \index{\_\_bit}
8985 This is a data-type and a storage class specifier.
8986 When a variable is declared as a bit, it is allocated into the bit addressable
8987 memory of 8051, e.g.:
8995 Writing 1 to this variable generates the assembly code:
9011 The bit addressable memory consists of 128 bits which are located from 0x20
9012 to 0x2f in data memory.
9015 Apart from this 8051 specific storage class most architectures support ANSI-C
9017 \begin_inset LatexCommand \index{bitfields}
9027 Not really meant as examples, but nevertheless showing what bitfields are
9028 about: device/include/mc68hc908qy.h and support/regression/tests/bitfields.c
9032 In accordance with ISO/IEC 9899 bits and bitfields without an explicit
9033 signed modifier are implemented as unsigned.
9034 \layout Subsubsection
9037 \begin_inset LatexCommand \index{sfr}
9042 \begin_inset LatexCommand \index{\_\_sfr}
9047 \begin_inset LatexCommand \index{sfr16}
9052 \begin_inset LatexCommand \index{\_\_sfr16}
9057 \begin_inset LatexCommand \index{sfr32}
9062 \begin_inset LatexCommand \index{\_\_sfr32}
9067 \begin_inset LatexCommand \index{\_\_sbit}
9074 Like the bit keyword,
9076 sfr / sfr16 / sfr32 / sbit
9078 signify both a data-type and storage class, they are used to describe the
9099 variables of a 8051, eg:
9105 \begin_inset LatexCommand \index{at}
9110 \begin_inset LatexCommand \index{\_\_at}
9114 0x80 P0;\SpecialChar ~
9115 /* special function register P0 at location 0x80 */
9117 /* 16 bit special function register combination for timer 0 */
9119 /* with the high byte at location 0x8C and the low byte at location 0x8A
9123 \begin_inset LatexCommand \index{at}
9128 \begin_inset LatexCommand \index{\_\_at}
9134 sbit at 0xd7 CY; /* CY (Carry Flag
9135 \begin_inset LatexCommand \index{Flags}
9140 \begin_inset LatexCommand \index{Carry flag}
9147 Special function registers which are located on an address dividable by
9148 8 are bit-addressable, an
9152 addresses a specific bit within these sfr.
9154 16 Bit and 32 bit special function register combinations which require a
9155 certain access order are better not declared using
9164 Allthough SDCC usually accesses them Least Significant Byte (LSB) first,
9165 this is not guaranteed.
9166 \layout Subsubsection
9169 \begin_inset LatexCommand \index{Pointer}
9173 to MCS51/DS390 specific memory spaces
9176 SDCC allows (via language extensions) pointers to explicitly point to any
9177 of the memory spaces
9178 \begin_inset LatexCommand \index{Memory model}
9183 In addition to the explicit pointers, the compiler uses (by default) generic
9184 pointers which can be used to point to any of the memory spaces.
9188 Pointer declaration examples:
9193 /* pointer physically in internal ram pointing to object in external ram
9196 xdata unsigned char * data p;
9200 /* pointer physically in external ram pointing to object in internal ram
9203 data unsigned char * xdata p;
9207 /* pointer physically in code rom pointing to data in xdata space */
9209 xdata unsigned char * code p;
9213 /* pointer physically in code space pointing to data in code space */
9215 code unsigned char * code p;
9219 /* the following is a generic pointer physically located in xdata space
9226 /* the following is a function pointer physically located in data space
9229 char (* data fp)(void);
9232 Well you get the idea.
9237 All unqualified pointers are treated as 3-byte (4-byte for the ds390)
9250 The highest order byte of the
9254 pointers contains the data space information.
9255 Assembler support routines are called whenever data is stored or retrieved
9261 These are useful for developing reusable library
9262 \begin_inset LatexCommand \index{Libraries}
9267 Explicitly specifying the pointer type will generate the most efficient
9269 \layout Subsubsection
9271 Notes on MCS51 memory
9272 \begin_inset LatexCommand \index{MCS51 memory}
9279 The 8051 family of microcontrollers have a minimum of 128 bytes of internal
9280 RAM memory which is structured as follows:
9284 - Bytes 00-1F - 32 bytes to hold up to 4 banks of the registers R0 to R7,
9287 - Bytes 20-2F - 16 bytes to hold 128 bit
9288 \begin_inset LatexCommand \index{bit}
9294 - Bytes 30-7F - 80 bytes for general purpose use.
9299 Additionally some members of the MCS51 family may have up to 128 bytes of
9300 additional, indirectly addressable, internal RAM memory (
9305 \begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
9310 \begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
9315 Furthermore, some chips may have some built in external memory (
9320 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
9325 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
9329 ) which should not be confused with the internal, directly addressable RAM
9335 \begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
9340 \begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
9345 Sometimes this built in
9349 memory has to be activated before using it (you can probably find this
9350 information on the datasheet of the microcontroller your are using, see
9352 \begin_inset LatexCommand \ref{sub:Startup-Code}
9360 Normally SDCC will only use the first bank
9361 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
9365 of registers (register bank 0), but it is possible to specify that other
9366 banks of registers (keyword
9373 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
9378 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
9384 ) should be used in interrupt
9385 \begin_inset LatexCommand \index{interrupt}
9390 \begin_inset LatexCommand \index{\_\_interrupt}
9395 By default, the compiler will place the stack after the last byte of allocated
9396 memory for variables.
9397 For example, if the first 2 banks of registers are used, and only four
9402 variables, it will position the base of the internal stack at address 20
9404 This implies that as the stack
9405 \begin_inset LatexCommand \index{stack}
9409 grows, it will use up the remaining register banks, and the 16 bytes used
9410 by the 128 bit variables, and 80 bytes for general purpose use.
9411 If any bit variables are used, the data variables will be placed in unused
9412 register banks and after the byte holding the last bit variable.
9413 For example, if register banks 0 and 1 are used, and there are 9 bit variables
9418 variables will be placed starting from address 0x10 to 0x20 and continue
9431 \begin_inset LatexCommand \index{-\/-data-loc <Value>}
9435 to specify the start address of the
9450 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
9454 to specify the size of the total internal RAM (
9466 By default the 8051 linker will place the stack after the last byte of (i)data
9479 \begin_inset LatexCommand \index{-\/-stack-loc <Value>}
9483 allows you to specify the start of the stack, i.e.
9484 you could start it after any data in the general purpose area.
9485 If your microcontroller has additional indirectly addressable internal
9490 ) you can place the stack on it.
9491 You may also need to use -
9502 \begin_inset LatexCommand \index{-\/-xdata-loc<Value>}
9506 to set the start address of the external RAM (
9521 \begin_inset LatexCommand \index{-\/-xram-size <Value>}
9525 to specify its size.
9526 Same goes for the code memory, using -
9537 \begin_inset LatexCommand \index{-\/-code-loc <Value>}
9552 \begin_inset LatexCommand \index{-\/-code-size <Value>}
9557 If in doubt, don't specify any options and see if the resulting memory
9558 layout is appropriate, then you can adjust it.
9561 The linker generates two files with memory allocation information.
9562 The first, with extension .map
9563 \begin_inset LatexCommand \index{<file>.map}
9567 shows all the variables and segments.
9568 The second with extension .mem
9569 \begin_inset LatexCommand \index{<file>.mem}
9573 shows the final memory layout.
9574 The linker will complain either if memory segments overlap, there is not
9575 enough memory, or there is not enough space for stack.
9576 If you get any linking warnings and/or errors related to stack or segments
9577 allocation, take a look at either the .map or .mem files to find out what
9579 The .mem file may even suggest a solution to the problem.
9582 Z80/Z180 Storage Class
9583 \begin_inset LatexCommand \index{Storage class}
9588 \layout Subsubsection
9591 \begin_inset LatexCommand \index{sfr}
9596 \begin_inset LatexCommand \index{\_\_sfr}
9600 (in/out to 8-bit addresses)
9604 \begin_inset LatexCommand \index{Z80}
9608 family has separate address spaces for memory and
9618 \begin_inset LatexCommand \index{I/O memory (Z80, Z180)}
9622 is accessed with special instructions, e.g.:
9627 sfr at 0x78 IoPort;\SpecialChar ~
9629 /* define a var in I/O space at 78h called IoPort */
9633 Writing 0x01 to this variable generates the assembly code:
9653 \layout Subsubsection
9656 \begin_inset LatexCommand \index{sfr}
9661 \begin_inset LatexCommand \index{\_\_sfr}
9665 (in/out to 16-bit addresses)
9672 is used to support 16 bit addresses in I/O memory e.g.:
9678 \begin_inset LatexCommand \index{at}
9683 \begin_inset LatexCommand \index{\_\_at}
9690 Writing 0x01 to this variable generates the assembly code:
9695 01 23 01\SpecialChar ~
9715 \layout Subsubsection
9718 \begin_inset LatexCommand \index{sfr}
9723 \begin_inset LatexCommand \index{\_\_sfr}
9727 (in0/out0 to 8 bit addresses on Z180
9728 \begin_inset LatexCommand \index{Z180}
9733 \begin_inset LatexCommand \index{HD64180}
9740 The compiler option -
9750 -portmode=180 (80) and a compiler #pragma\SpecialChar ~
9752 \begin_inset LatexCommand \index{\#pragma portmode}
9756 =z180 (z80) is used to turn on (off) the Z180/HD64180 port addressing instructio
9766 If you include the file z180.h this will be set automatically.
9770 \begin_inset LatexCommand \index{Storage class}
9775 \layout Subsubsection
9778 \begin_inset LatexCommand \index{data (hc08 storage class)}
9783 \begin_inset LatexCommand \index{\_\_data (hc08 storage class)}
9790 The data storage class declares a variable that resides in the first 256
9791 bytes of memory (the direct page).
9792 The HC08 is most efficient at accessing variables (especially pointers)
9794 \layout Subsubsection
9797 \begin_inset LatexCommand \index{xdata (hc08 storage class)}
9802 \begin_inset LatexCommand \index{\_\_xdata (hc08 storage class)}
9809 The xdata storage class declares a variable that can reside anywhere in
9811 This is the default if no storage class is specified.
9816 \begin_inset LatexCommand \index{Absolute addressing}
9823 Data items can be assigned an absolute address with the
9826 \begin_inset LatexCommand \index{at}
9831 \begin_inset LatexCommand \index{\_\_at}
9837 keyword, in addition to a storage class, e.g.:
9843 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
9848 \begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
9853 \begin_inset LatexCommand \index{at}
9858 \begin_inset LatexCommand \index{\_\_at}
9862 0x7ffe unsigned int chksum;
9865 In the above example the variable chksum will be located at 0x7ffe and 0x7fff
9866 of the external ram.
9871 reserve any space for variables declared in this way (they are implemented
9872 with an equate in the assembler).
9873 Thus it is left to the programmer to make sure there are no overlaps with
9874 other variables that are declared without the absolute address.
9875 The assembler listing file (.lst
9876 \begin_inset LatexCommand \index{<file>.lst}
9880 ) and the linker output files (.rst
9881 \begin_inset LatexCommand \index{<file>.rst}
9886 \begin_inset LatexCommand \index{<file>.map}
9890 ) are good places to look for such overlaps.
9891 Variables with an absolute address are
9896 \begin_inset LatexCommand \index{Variable initialization}
9903 In case of memory mapped I/O devices the keyword
9907 has to be used to tell the compiler that accesses might not be removed:
9913 \begin_inset LatexCommand \index{volatile}
9918 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
9923 \begin_inset LatexCommand \index{at}
9927 0x8000 unsigned char PORTA_8255;
9930 For some architectures (mcs51) array accesses are more efficient if an (xdata/fa
9935 \begin_inset LatexCommand \index{Aligned array}
9942 starts at a block (256 byte) boundary
9943 \begin_inset LatexCommand \index{block boundary}
9948 \begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
9954 Absolute addresses can be specified for variables in all storage classes,
9961 \begin_inset LatexCommand \index{bit}
9966 \begin_inset LatexCommand \index{at}
9973 The above example will allocate the variable at offset 0x02 in the bit-addressab
9975 There is no real advantage to assigning absolute addresses to variables
9976 in this manner, unless you want strict control over all the variables allocated.
9977 One possible use would be to write hardware portable code.
9978 For example, if you have a routine that uses one or more of the microcontroller
9979 I/O pins, and such pins are different for two different hardwares, you
9980 can declare the I/O pins in your routine using:
9986 \begin_inset LatexCommand \index{volatile}
9990 bit MOSI;\SpecialChar ~
9994 /* master out, slave in */
9996 extern volatile bit MISO;\SpecialChar ~
10000 /* master in, slave out */
10002 extern volatile bit MCLK;\SpecialChar ~
10010 /* Input and Output of a byte on a 3-wire serial bus.
10015 If needed adapt polarity of clock, polarity of data and bit order
10020 unsigned char spi_io(unsigned char out_byte)
10044 MOSI = out_byte & 0x80;
10074 /* _asm nop _endasm; */\SpecialChar ~
10082 /* for slow peripherals */
10133 Then, someplace in the code for the first hardware you would use
10139 \begin_inset LatexCommand \index{at}
10144 \begin_inset LatexCommand \index{\_\_at}
10148 0x80 MOSI;\SpecialChar ~
10152 /* I/O port 0, bit 0 */
10154 bit at 0x81 MISO;\SpecialChar ~
10158 /* I/O port 0, bit 1 */
10160 bit at 0x82 MCLK;\SpecialChar ~
10164 /* I/O port 0, bit 2 */
10167 Similarly, for the second hardware you would use
10172 bit at 0x83 MOSI;\SpecialChar ~
10176 /* I/O port 0, bit 3 */
10178 bit at 0x91 MISO;\SpecialChar ~
10182 /* I/O port 1, bit 1 */
10185 \begin_inset LatexCommand \index{bit}
10189 at 0x92 MCLK;\SpecialChar ~
10193 /* I/O port 1, bit 2 */
10196 and you can use the same hardware dependent routine without changes, as
10197 for example in a library.
10198 This is somehow similar to sbit, but only one absolute address has to be
10199 specified in the whole project.
10203 \begin_inset LatexCommand \index{Parameters}
10208 \begin_inset LatexCommand \index{function parameter}
10213 \begin_inset LatexCommand \index{local variables}
10218 \begin_inset LatexCommand \label{sec:Parameters-and-Local-Variables}
10225 Automatic (local) variables and parameters to functions can either be placed
10226 on the stack or in data-space.
10227 The default action of the compiler is to place these variables in the internal
10228 RAM (for small model) or external RAM (for large model).
10229 This in fact makes them similar to
10232 \begin_inset LatexCommand \index{static}
10238 so by default functions are non-reentrant
10239 \begin_inset LatexCommand \index{reentrant}
10248 They can be placed on the stack
10249 \begin_inset LatexCommand \index{stack}
10266 \begin_inset LatexCommand \index{-\/-stack-auto}
10274 #pragma\SpecialChar ~
10278 \begin_inset LatexCommand \index{\#pragma stackauto}
10285 \begin_inset LatexCommand \index{reentrant}
10291 keyword in the function declaration, e.g.:
10296 unsigned char foo(char i) reentrant
10310 Since stack space on 8051 is limited, the
10328 option should be used sparingly.
10329 Note that the reentrant keyword just means that the parameters & local
10330 variables will be allocated to the stack, it
10334 mean that the function is register bank
10335 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
10344 \begin_inset LatexCommand \index{local variables}
10348 can be assigned storage classes and absolute
10349 \begin_inset LatexCommand \index{Absolute addressing}
10358 unsigned char foo()
10366 xdata unsigned char i;
10379 \begin_inset LatexCommand \index{at}
10383 0x31 unsigned char j;
10395 In the above example the variable
10399 will be allocated in the external ram,
10403 in bit addressable space and
10422 or when a function is declared as
10426 this should only be done for static variables.
10430 \begin_inset LatexCommand \index{function parameter}
10434 however are not allowed any storage class
10435 \begin_inset LatexCommand \index{Storage class}
10439 , (storage classes for parameters will be ignored), their allocation is
10440 governed by the memory model in use, and the reentrancy options.
10443 It is however allowed to use bit parameters in reentrant functions and also
10444 non-static local bit variables are supported.
10445 Efficient use is limited to 8 semi-bitregisters in bit space.
10446 They are pushed and popped to stack as a single byte just like the normal
10451 \begin_inset LatexCommand \label{sub:Overlaying}
10456 \begin_inset LatexCommand \index{Overlaying}
10464 \begin_inset LatexCommand \index{reentrant}
10468 functions SDCC will try to reduce internal ram space usage by overlaying
10469 parameters and local variables of a function (if possible).
10470 Parameters and local variables
10471 \begin_inset LatexCommand \index{local variables}
10475 of a function will be allocated to an overlayable segment if the function
10478 no other function calls and the function is non-reentrant and the memory
10480 \begin_inset LatexCommand \index{Memory model}
10487 If an explicit storage class
10488 \begin_inset LatexCommand \index{Storage class}
10492 is specified for a local variable, it will NOT be overlayed.
10495 Note that the compiler (not the linkage editor) makes the decision for overlayin
10497 Functions that are called from an interrupt service routine should be preceded
10498 by a #pragma\SpecialChar ~
10500 \begin_inset LatexCommand \index{\#pragma nooverlay}
10504 if they are not reentrant.
10507 Also note that the compiler does not do any processing of inline assembler
10508 code, so the compiler might incorrectly assign local variables and parameters
10509 of a function into the overlay segment if the inline assembler code calls
10510 other c-functions that might use the overlay.
10511 In that case the #pragma\SpecialChar ~
10512 nooverlay should be used.
10515 Parameters and local variables of functions that contain 16 or 32 bit multiplica
10517 \begin_inset LatexCommand \index{Multiplication}
10522 \begin_inset LatexCommand \index{Division}
10526 will NOT be overlayed since these are implemented using external functions,
10535 \begin_inset LatexCommand \index{\#pragma nooverlay}
10541 void set_error(unsigned char errcd)
10557 void some_isr () interrupt
10558 \begin_inset LatexCommand \index{interrupt}
10588 In the above example the parameter
10596 would be assigned to the overlayable segment if the #pragma\SpecialChar ~
10598 not present, this could cause unpredictable runtime behavior when called
10599 from an interrupt service routine.
10600 The #pragma\SpecialChar ~
10601 nooverlay ensures that the parameters and local variables for
10602 the function are NOT overlayed.
10605 Interrupt Service Routines
10606 \begin_inset LatexCommand \label{sub:Interrupt-Service-Routines}
10613 General Information
10628 outines to be coded in C, with some extended keywords.
10633 void timer_isr (void) interrupt 1 using 1
10647 The optional number following the
10650 \begin_inset LatexCommand \index{interrupt}
10655 \begin_inset LatexCommand \index{\_\_interrupt}
10661 keyword is the interrupt number this routine will service.
10662 When present, the compiler will insert a call to this routine in the interrupt
10663 vector table for the interrupt number specified.
10664 If you have multiple source files in your project, interrupt service routines
10665 can be present in any of them, but a prototype of the isr MUST be present
10666 or included in the file that contains the function
10674 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
10679 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
10685 keyword can be used to tell the compiler to use the specified register
10686 bank (8051 specific) when generating code for this function.
10692 Interrupt service routines open the door for some very interesting bugs:
10694 If an interrupt service routine changes variables which are accessed by
10695 other functions these variables have to be declared
10700 \begin_inset LatexCommand \index{volatile}
10708 If the access to these variables is not
10711 \begin_inset LatexCommand \index{atomic}
10718 the processor needs more than one instruction for the access and could
10719 be interrupted while accessing the variable) the interrupt must be disabled
10720 during the access to avoid inconsistent data.
10721 Access to 16 or 32 bit variables is obviously not atomic on 8 bit CPUs
10722 and should be protected by disabling interrupts.
10723 You're not automatically on the safe side if you use 8 bit variables though.
10724 We need an example here: f.e.
10725 on the 8051 the harmless looking
10726 \begin_inset Quotes srd
10731 flags\SpecialChar ~
10736 \begin_inset Quotes sld
10745 \begin_inset Quotes srd
10750 flags\SpecialChar ~
10755 \begin_inset Quotes sld
10758 from within an interrupt routine might get lost if the interrupt occurs
10761 \begin_inset Quotes sld
10766 counter\SpecialChar ~
10771 \begin_inset Quotes srd
10774 is not atomic on the 8051 even if
10778 is located in data memory.
10779 Bugs like these are hard to reproduce and can cause a lot of trouble.
10783 The return address and the registers used in the interrupt service routine
10784 are saved on the stack
10785 \begin_inset LatexCommand \index{stack}
10789 so there must be sufficient stack space.
10790 If there isn't variables or registers (or even the return address itself)
10797 \begin_inset LatexCommand \index{stack overflow}
10801 is most likely to happen if the interrupt occurs during the
10802 \begin_inset Quotes sld
10806 \begin_inset Quotes srd
10809 subroutine when the stack is already in use for f.e.
10810 many return addresses.
10813 A special note here, int (16 bit) and long (32 bit) integer division
10814 \begin_inset LatexCommand \index{Division}
10819 \begin_inset LatexCommand \index{Multiplication}
10824 \begin_inset LatexCommand \index{Modulus}
10829 \begin_inset LatexCommand \index{Floating point support}
10833 operations are implemented using external support routines developed in
10835 If an interrupt service routine needs to do any of these operations then
10836 the support routines (as mentioned in a following section) will have to
10837 be recompiled using the
10850 \begin_inset LatexCommand \index{-\/-stack-auto}
10856 option and the source file will need to be compiled using the
10871 \begin_inset LatexCommand \index{-\/-int-long-reent}
10878 Calling other functions from an interrupt service routine is not recommended,
10879 avoid it if possible.
10880 Note that when some function is called from an interrupt service routine
10881 it should be preceded by a #pragma\SpecialChar ~
10883 \begin_inset LatexCommand \index{\#pragma nooverlay}
10887 if it is not reentrant.
10888 Furthermore nonreentrant functions should not be called from the main program
10889 while the interrupt service routine might be active.
10895 \begin_inset LatexCommand \ref{sub:Overlaying}
10900 about Overlaying and section
10901 \begin_inset LatexCommand \ref{sub:Functions-using-private-banks}
10906 about Functions using private register banks.
10909 MCS51/DS390 Interrupt Service Routines
10912 Interrupt numbers and the corresponding address & descriptions for the Standard
10913 8051/8052 are listed below.
10914 SDCC will automatically adjust the interrupt vector table to the maximum
10915 interrupt number specified.
10921 \begin_inset Tabular
10922 <lyxtabular version="3" rows="7" columns="3">
10924 <column alignment="center" valignment="top" leftline="true" width="0in">
10925 <column alignment="center" valignment="top" leftline="true" width="0in">
10926 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0in">
10927 <row topline="true" bottomline="true">
10928 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
10936 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
10944 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
10953 <row topline="true">
10954 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
10962 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
10970 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
10979 <row topline="true">
10980 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
10988 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
10996 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
11005 <row topline="true">
11006 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11014 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11022 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
11031 <row topline="true">
11032 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11040 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11048 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
11057 <row topline="true">
11058 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11066 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11074 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
11083 <row topline="true" bottomline="true">
11084 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11092 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
11100 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
11118 If the interrupt service routine is defined without
11121 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
11126 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
11132 a register bank or with register bank 0 (
11136 0), the compiler will save the registers used by itself on the stack upon
11137 entry and restore them at exit, however if such an interrupt service routine
11138 calls another function then the entire register bank will be saved on the
11140 This scheme may be advantageous for small interrupt service routines which
11141 have low register usage.
11144 If the interrupt service routine is defined to be using a specific register
11149 & psw are saved and restored, if such an interrupt service routine calls
11150 another function (using another register bank) then the entire register
11151 bank of the called function will be saved on the stack.
11152 This scheme is recommended for larger interrupt service routines.
11155 HC08 Interrupt Service Routines
11158 Since the number of interrupts available is chip specific and the interrupt
11159 vector table always ends at the last byte of memory, the interrupt numbers
11160 corresponds to the interrupt vectors in reverse order of address.
11161 For example, interrupt 1 will use the interrupt vector at 0xfffc, interrupt
11162 2 will use the interrupt vector at 0xfffa, and so on.
11163 However, interrupt 0 (the reset vector at 0xfffe) is not redefinable in
11164 this way; instead see section
11165 \begin_inset LatexCommand \ref{sub:Startup-Code}
11169 for details on customizing startup.
11172 Z80 Interrupt Service Routines
11175 The Z80 uses several different methods for determining the correct interrupt
11176 vector depending on the hardware implementation.
11177 Therefore, SDCC ignores the optional interrupt number and does not attempt
11178 to generate an interrupt vector table.
11181 By default, SDCC generates code for a maskable interrupt, which uses an
11182 RETI instruction to return from the interrupt.
11183 To write an interrupt handler for the non-maskable interrupt, which needs
11184 an RETN instruction instead, add the
11193 void nmi_isr (void) critical interrupt
11207 Enabling and Disabling Interrupts
11210 Critical Functions and Critical Statements
11213 A special keyword may be associated with a block or a function declaring
11219 SDCC will generate code to disable all interrupts
11220 \begin_inset LatexCommand \index{interrupt}
11224 upon entry to a critical function and restore the interrupt enable to the
11225 previous state before returning.
11226 Nesting critical functions will need one additional byte on the stack
11227 \begin_inset LatexCommand \index{stack}
11236 int foo () critical
11237 \begin_inset LatexCommand \index{critical}
11242 \begin_inset LatexCommand \index{\_\_critical}
11267 The critical attribute maybe used with other attributes like
11277 may also be used to disable interrupts more locally:
11285 More than one statement could have been included in the block.
11288 Enabling and Disabling Interrupts directly
11292 \begin_inset LatexCommand \index{interrupt}
11296 can also be disabled and enabled directly (8051):
11301 EA = 0;\SpecialChar ~
11364 EA = 1;\SpecialChar ~
11431 On other architectures which have seperate opcodes for enabling and disabling
11432 interrupts you might want to make use of defines with inline assembly
11433 \begin_inset LatexCommand \index{Assembler routines}
11443 \begin_inset LatexCommand \index{\_asm}
11452 \begin_inset LatexCommand \index{\_endasm}
11461 #define SEI _asm\SpecialChar ~
11473 Note: it is sometimes sufficient to disable only a specific interrupt source
11475 a timer or serial interrupt by manipulating an
11478 \begin_inset LatexCommand \index{interrupt mask}
11488 Usually the time during which interrupts are disabled should be kept as
11490 This minimizes both
11495 \begin_inset LatexCommand \index{interrupt latency}
11499 (the time between the occurrence of the interrupt and the execution of
11500 the first code in the interrupt routine) and
11505 \begin_inset LatexCommand \index{interrupt jitter}
11509 (the difference between the shortest and the longest interrupt latency).
11510 These really are something different, f.e.
11511 a serial interrupt has to be served before its buffer overruns so it cares
11512 for the maximum interrupt latency, whereas it does not care about jitter.
11513 On a loudspeaker driven via a digital to analog converter which is fed
11514 by an interrupt a latency of a few milliseconds might be tolerable, whereas
11515 a much smaller jitter will be very audible.
11518 You can reenable interrupts within an interrupt routine and on some architecture
11519 s you can make use of two (or more) levels of
11521 interrupt priorities
11524 \begin_inset LatexCommand \index{interrupt priority}
11529 On some architectures which don't support interrupt priorities these can
11530 be implemented by manipulating the interrupt mask and reenabling interrupts
11531 within the interrupt routine.
11532 Check there is sufficient space on the stack
11533 \begin_inset LatexCommand \index{stack}
11537 and don't add complexity unless you have to.
11542 \begin_inset LatexCommand \index{semaphore}
11546 locking (mcs51/ds390)
11549 Some architectures (mcs51/ds390) have an atomic
11550 \begin_inset LatexCommand \index{atomic}
11563 These type of instructions are typically used in preemptive multitasking
11564 systems, where a routine f.e.
11565 claims the use of a data structure ('acquires a lock
11566 \begin_inset LatexCommand \index{lock}
11570 on it'), makes some modifications and then releases the lock when the data
11571 structure is consistent again.
11572 The instruction may also be used if interrupt and non-interrupt code have
11573 to compete for a resource.
11574 With the atomic bit test and clear instruction interrupts
11575 \begin_inset LatexCommand \index{interrupt}
11579 don't have to be disabled for the locking operation.
11583 SDCC generates this instruction if the source follows this pattern:
11589 \begin_inset LatexCommand \index{volatile}
11593 bit resource_is_free;
11597 if (resource_is_free)
11607 resource_is_free=0;
11620 resource_is_free=1;
11627 Note, mcs51 and ds390 support only an atomic
11628 \begin_inset LatexCommand \index{atomic}
11636 instruction (as opposed to atomic bit test and
11641 Functions using private register banks
11642 \begin_inset LatexCommand \label{sub:Functions-using-private-banks}
11649 Some architectures have support for quickly changing register sets.
11650 SDCC supports this feature with the
11653 \begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
11658 \begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
11664 attribute (which tells the compiler to use a register bank
11665 \begin_inset LatexCommand \index{register bank (mcs51, ds390)}
11669 other than the default bank zero).
11670 It should only be applied to
11673 \begin_inset LatexCommand \index{interrupt}
11679 functions (see footnote below).
11680 This will in most circumstances make the generated ISR code more efficient
11681 since it will not have to save registers on the stack.
11688 attribute will have no effect on the generated code for a
11692 function (but may occasionally be useful anyway
11698 possible exception: if a function is called ONLY from 'interrupt' functions
11699 using a particular bank, it can be declared with the same 'using' attribute
11700 as the calling 'interrupt' functions.
11701 For instance, if you have several ISRs using bank one, and all of them
11702 call memcpy(), it might make sense to create a specialized version of memcpy()
11703 'using 1', since this would prevent the ISR from having to save bank zero
11704 to the stack on entry and switch to bank zero before calling the function
11711 (pending: I don't think this has been done yet)
11718 function using a non-zero bank will assume that it can trash that register
11719 bank, and will not save it.
11720 Since high-priority interrupts
11721 \begin_inset LatexCommand \index{interrupts}
11726 \begin_inset LatexCommand \index{interrupt priority}
11730 can interrupt low-priority ones on the 8051 and friends, this means that
11731 if a high-priority ISR
11735 a particular bank occurs while processing a low-priority ISR
11739 the same bank, terrible and bad things can happen.
11740 To prevent this, no single register bank should be
11744 by both a high priority and a low priority ISR.
11745 This is probably most easily done by having all high priority ISRs use
11746 one bank and all low priority ISRs use another.
11747 If you have an ISR which can change priority at runtime, you're on your
11748 own: I suggest using the default bank zero and taking the small performance
11752 It is most efficient if your ISR calls no other functions.
11753 If your ISR must call other functions, it is most efficient if those functions
11754 use the same bank as the ISR (see note 1 below); the next best is if the
11755 called functions use bank zero.
11756 It is very inefficient to call a function using a different, non-zero bank
11762 \begin_inset LatexCommand \label{sub:Startup-Code}
11767 \begin_inset LatexCommand \index{Startup code}
11774 MCS51/DS390 Startup Code
11777 The compiler inserts a call to the C routine
11779 _sdcc_external_startup()
11780 \begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
11789 at the start of the CODE area.
11790 This routine is in the runtime library
11791 \begin_inset LatexCommand \index{Runtime library}
11796 By default this routine returns 0, if this routine returns a non-zero value,
11797 the static & global variable initialization will be skipped and the function
11798 main will be invoked.
11799 Otherwise static & global variables will be initialized before the function
11803 _sdcc_external_startup()
11805 routine to your program to override the default if you need to setup hardware
11806 or perform some other critical operation prior to static & global variable
11808 \begin_inset LatexCommand \index{Variable initialization}
11813 On some mcs51 variants xdata
11814 \begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
11818 memory has to be explicitly enabled before it can be accessed or if the
11819 watchdog needs to be disabled, this is the place to do it.
11820 The startup code clears all internal data memory, 256 bytes by default,
11821 but from 0 to n-1 if
11834 \begin_inset LatexCommand \index{-\/-iram-size <Value>}
11841 (recommended for Chipcon CC1010).
11844 See also the compiler option
11863 \begin_inset LatexCommand \index{-\/-no-xinit-opt}
11868 \begin_inset LatexCommand \ref{sub:MCS51-variants}
11873 about MCS51-variants.
11879 The HC08 startup code follows the same scheme as the MCS51 startup code.
11885 On the Z80 the startup code is inserted by linking with crt0.o which is generated
11886 from sdcc/device/lib/z80/crt0.s.
11887 If you need a different startup code you can use the compiler option
11908 \begin_inset LatexCommand \index{-\/-no-std-crt0}
11912 and provide your own crt0.o.
11916 Inline Assembler Code
11917 \begin_inset LatexCommand \index{Assembler routines}
11924 A Step by Step Introduction
11925 \begin_inset LatexCommand \label{sub:A-Step-by Assembler Introduction}
11932 Starting from a small snippet of c-code this example shows for the MCS51
11933 how to use inline assembly, access variables, a function parameter and
11934 an array in xdata memory.
11935 The example uses an MCS51 here but is easily adapted for other architectures.
11936 This is a buffer routine which should be optimized:
11943 \begin_inset LatexCommand \index{far (storage class)}
11948 \begin_inset LatexCommand \index{\_\_far (storage class)}
11953 \begin_inset LatexCommand \index{at}
11958 \begin_inset LatexCommand \index{\_\_at}
11963 \begin_inset LatexCommand \index{Aligned array}
11969 unsigned char head,tail;
11973 void to_buffer( unsigned char c )
11981 if( head != tail-1 )
11991 buf[ head++ ] = c;\SpecialChar ~
11995 /* access to a 256 byte aligned array */
12000 If the code snippet (assume it is saved in buffer.c) is compiled with SDCC
12001 then a corresponding buffer.asm file is generated.
12002 We define a new function
12006 in file buffer.c in which we cut and paste the generated code, removing
12007 unwanted comments and some ':'.
12009 \begin_inset Quotes sld
12013 \begin_inset Quotes srd
12017 \begin_inset Quotes sld
12021 \begin_inset Quotes srd
12024 to the beginning and the end of the function body:
12030 /* With a cut and paste from the .asm file, we have something to start with.
12035 The function is not yet OK! (registers aren't saved) */
12037 void to_buffer_asm( unsigned char c )
12046 \begin_inset LatexCommand \index{\_asm}
12051 \begin_inset LatexCommand \index{\_\_asm}
12065 ;buffer.c if( head != tail-1 )
12113 ;buffer.c buf[ head++ ] = c; /* access to a 256 byte aligned array */
12114 \begin_inset LatexCommand \index{Aligned array}
12179 \begin_inset LatexCommand \index{\_endasm}
12184 \begin_inset LatexCommand \index{\_\_endasm}
12193 The new file buffer.c should compile with only one warning about the unreferenced
12194 function argument 'c'.
12195 Now we hand-optimize the assembly code and insert an #define USE_ASSEMBLY
12196 (1) and finally have:
12202 unsigned char far at 0x7f00 buf[0x100];
12204 unsigned char head,tail;
12206 #define USE_ASSEMBLY (1)
12214 void to_buffer( unsigned char c )
12222 if( head != tail-1 )
12242 void to_buffer( unsigned char c )
12250 c; // to avoid warning: unreferenced function argument
12257 \begin_inset LatexCommand \index{\_asm}
12262 \begin_inset LatexCommand \index{\_\_asm}
12276 ; save used registers here.
12287 ; If we were still using r2,r3 we would have to push them here.
12290 ; if( head != tail-1 )
12333 ; we could do an ANL a,#0x0f here to use a smaller buffer (see below)
12357 ; buf[ head++ ] = c;
12368 a,dpl \SpecialChar ~
12375 ; dpl holds lower byte of function argument
12386 dpl,_head \SpecialChar ~
12389 ; buf is 0x100 byte aligned so head can be used directly
12431 ; we could do an ANL _head,#0x0f here to use a smaller buffer (see above)
12443 ; restore used registers here
12450 \begin_inset LatexCommand \index{\_endasm}
12455 \begin_inset LatexCommand \index{\_\_endasm}
12466 The inline assembler code can contain any valid code understood by the assembler
12467 , this includes any assembler directives and comment lines
12473 The assembler does not like some characters like ':' or ''' in comments.
12474 You'll find an 100+ pages assembler manual in sdcc/as/doc/asxhtm.html
12475 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
12480 \begin_inset LatexCommand \index{Assembler documentation}
12488 The compiler does not do any validation of the code within the
12491 \begin_inset LatexCommand \index{\_asm}
12496 \begin_inset LatexCommand \index{\_\_asm}
12504 \begin_inset LatexCommand \index{\_endasm}
12509 \begin_inset LatexCommand \index{\_\_endasm}
12518 Specifically it will not know which registers are used and thus register
12520 \begin_inset LatexCommand \index{push/pop}
12524 has to be done manually.
12528 It is recommended that each assembly instruction (including labels) be placed
12529 in a separate line (as the example shows).
12543 \begin_inset LatexCommand \index{-\/-peep-asm}
12549 command line option is used, the inline assembler code will be passed through
12550 the peephole optimizer
12551 \begin_inset LatexCommand \index{Peephole optimizer}
12556 There are only a few (if any) cases where this option makes sense, it might
12557 cause some unexpected changes in the inline assembler code.
12558 Please go through the peephole optimizer rules defined in file
12562 before using this option.
12566 \begin_inset LatexCommand \label{sub:Naked-Functions}
12571 \begin_inset LatexCommand \index{Naked functions}
12578 A special keyword may be associated with a function declaring it as
12581 \begin_inset LatexCommand \index{\_naked}
12586 \begin_inset LatexCommand \index{\_\_naked}
12597 function modifier attribute prevents the compiler from generating prologue
12598 \begin_inset LatexCommand \index{function prologue}
12603 \begin_inset LatexCommand \index{function epilogue}
12607 code for that function.
12608 This means that the user is entirely responsible for such things as saving
12609 any registers that may need to be preserved, selecting the proper register
12610 bank, generating the
12614 instruction at the end, etc.
12615 Practically, this means that the contents of the function must be written
12616 in inline assembler.
12617 This is particularly useful for interrupt functions, which can have a large
12618 (and often unnecessary) prologue/epilogue.
12619 For example, compare the code generated by these two functions:
12625 \begin_inset LatexCommand \index{volatile}
12629 data unsigned char counter;
12633 void simpleInterrupt(void) interrupt
12634 \begin_inset LatexCommand \index{interrupt}
12639 \begin_inset LatexCommand \index{\_\_interrupt}
12657 void nakedInterrupt(void) interrupt 2 _naked
12666 \begin_inset LatexCommand \index{\_asm}
12671 \begin_inset LatexCommand \index{\_\_asm}
12688 _counter ; does not change flags, no need to save psw
12700 ; MUST explicitly include ret or reti in _naked function.
12707 \begin_inset LatexCommand \index{\_endasm}
12712 \begin_inset LatexCommand \index{\_\_endasm}
12721 For an 8051 target, the generated simpleInterrupt looks like:
12862 whereas nakedInterrupt looks like:
12877 _counter ; does not change flags, no need to save psw
12895 ; MUST explicitly include ret or reti in _naked function
12898 The related directive #pragma exclude
12899 \begin_inset LatexCommand \index{\#pragma exclude}
12903 allows a more fine grained control over pushing & popping
12904 \begin_inset LatexCommand \index{push/pop}
12911 While there is nothing preventing you from writing C code inside a
12915 function, there are many ways to shoot yourself in the foot doing this,
12916 and it is recommended that you stick to inline assembler.
12919 Use of Labels within Inline Assembler
12922 SDCC allows the use of in-line assembler with a few restrictions regarding
12924 In older versions of the compiler all labels defined within inline assembler
12933 where nnnn is a number less than 100 (which implies a limit of utmost 100
12934 inline assembler labels
12948 \begin_inset LatexCommand \index{\_asm}
12953 \begin_inset LatexCommand \index{\_\_asm}
12983 \begin_inset LatexCommand \index{\_endasm}
12988 \begin_inset LatexCommand \index{\_\_endasm}
12995 Inline assembler code cannot reference any C-Labels, however it can reference
12997 \begin_inset LatexCommand \index{Labels}
13001 defined by the inline assembler, e.g.:
13026 ; some assembler code
13046 /* some more c code */
13048 clabel:\SpecialChar ~
13050 /* inline assembler cannot reference this label */
13062 $0003: ;label (can be referenced by inline assembler only)
13069 \begin_inset LatexCommand \index{\_endasm}
13074 \begin_inset LatexCommand \index{\_\_endasm}
13084 /* some more c code */
13089 In other words inline assembly code can access labels defined in inline
13090 assembly within the scope of the function.
13091 The same goes the other way, i.e.
13092 labels defines in inline assembly can not be accessed by C statements.
13095 Interfacing with Assembler Code
13096 \begin_inset LatexCommand \index{Assembler routines}
13103 Global Registers used for Parameter Passing
13104 \begin_inset LatexCommand \index{Parameter passing}
13111 The compiler always uses the global registers
13114 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
13119 \begin_inset LatexCommand \index{DPTR}
13124 \begin_inset LatexCommand \index{B (mcs51, ds390 register)}
13133 \begin_inset LatexCommand \index{ACC (mcs51, ds390 register)}
13139 to pass the first parameter to a routine.
13140 The second parameter onwards is either allocated on the stack (for reentrant
13151 -stack-auto is used) or in data / xdata memory (depending on the memory
13156 Assembler Routine (non-reentrant)
13159 In the following example
13160 \begin_inset LatexCommand \index{reentrant}
13165 \begin_inset LatexCommand \index{Assembler routines (non-reentrant)}
13169 the function c_func calls an assembler routine asm_func, which takes two
13171 \begin_inset LatexCommand \index{function parameter}
13180 extern int asm_func(unsigned char, unsigned char);
13184 int c_func (unsigned char i, unsigned char j)
13192 return asm_func(i,j);
13206 return c_func(10,9);
13211 The corresponding assembler function is:
13216 .globl _asm_func_PARM_2
13317 \begin_inset LatexCommand \index{DPTR, DPH, DPL}
13334 Note here that the return values
13335 \begin_inset LatexCommand \index{return value}
13339 are placed in 'dpl' - One byte return value, 'dpl' LSB & 'dph' MSB for
13341 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
13342 b' & 'acc' for four byte values.
13345 The parameter naming convention is _<function_name>_PARM_<n>, where n is
13346 the parameter number starting from 1, and counting from the left.
13347 The first parameter is passed in
13348 \begin_inset Quotes eld
13352 \begin_inset Quotes erd
13355 for a one byte parameter,
13356 \begin_inset Quotes eld
13360 \begin_inset Quotes erd
13364 \begin_inset Quotes eld
13368 \begin_inset Quotes erd
13371 for three bytes and
13372 \begin_inset Quotes eld
13376 \begin_inset Quotes erd
13379 for a four bytes parameter.
13380 The variable name for the second parameter will be _<function_name>_PARM_2.
13384 Assemble the assembler routine with the following command:
13391 asx8051 -losg asmfunc.asm
13398 Then compile and link the assembler routine to the C source file with the
13406 sdcc cfunc.c asmfunc.rel
13409 Assembler Routine (reentrant)
13413 \begin_inset LatexCommand \index{reentrant}
13418 \begin_inset LatexCommand \index{Assembler routines (reentrant)}
13422 the second parameter
13423 \begin_inset LatexCommand \index{function parameter}
13427 onwards will be passed on the stack, the parameters are pushed from right
13429 after the call the leftmost parameter will be on the top of the stack.
13430 Here is an example:
13435 extern int asm_func(unsigned char, unsigned char);
13439 int c_func (unsigned char i, unsigned char j) reentrant
13447 return asm_func(i,j);
13461 return c_func(10,9);
13466 The corresponding assembler routine is:
13566 The compiling and linking procedure remains the same, however note the extra
13567 entry & exit linkage required for the assembler code, _bp is the stack
13568 frame pointer and is used to compute the offset into the stack for parameters
13569 and local variables.
13573 \begin_inset LatexCommand \index{int (16 bit)}
13578 \begin_inset LatexCommand \index{long (32 bit)}
13585 For signed & unsigned int (16 bit) and long (32 bit) variables, division,
13586 multiplication and modulus operations are implemented by support routines.
13587 These support routines are all developed in ANSI-C to facilitate porting
13588 to other MCUs, although some model specific assembler optimizations are
13590 The following files contain the described routines, all of them can be
13591 found in <installdir>/share/sdcc/lib.
13597 \begin_inset Tabular
13598 <lyxtabular version="3" rows="11" columns="2">
13600 <column alignment="center" valignment="top" leftline="true" width="0">
13601 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
13602 <row topline="true" bottomline="true">
13603 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13613 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13624 <row topline="true">
13625 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13633 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13638 16 bit multiplication
13642 <row topline="true">
13643 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13651 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13656 signed 16 bit division (calls _divuint)
13660 <row topline="true">
13661 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13669 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13674 unsigned 16 bit division
13678 <row topline="true">
13679 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13687 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13692 signed 16 bit modulus (calls _moduint)
13696 <row topline="true">
13697 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13705 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13710 unsigned 16 bit modulus
13714 <row topline="true">
13715 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13723 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13728 32 bit multiplication
13732 <row topline="true">
13733 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13741 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13746 signed 32 division (calls _divulong)
13750 <row topline="true">
13751 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13759 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13764 unsigned 32 division
13768 <row topline="true">
13769 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13777 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13782 signed 32 bit modulus (calls _modulong)
13786 <row topline="true" bottomline="true">
13787 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13795 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13800 unsigned 32 bit modulus
13813 Since they are compiled as
13818 \begin_inset LatexCommand \index{reentrant}
13823 \begin_inset LatexCommand \index{interrupt}
13827 service routines should not do any of the above operations.
13828 If this is unavoidable then the above routines will need to be compiled
13842 \begin_inset LatexCommand \index{-\/-stack-auto}
13848 option, after which the source program will have to be compiled with
13861 \begin_inset LatexCommand \index{-\/-int-long-reent}
13868 Notice that you don't have to call these routines directly.
13869 The compiler will use them automatically every time an integer operation
13873 Floating Point Support
13874 \begin_inset LatexCommand \index{Floating point support}
13881 SDCC supports IEEE (single precision 4 bytes) floating point numbers.The
13882 floating point support routines are derived from gcc's floatlib.c and consist
13883 of the following routines:
13891 \begin_inset Tabular
13892 <lyxtabular version="3" rows="17" columns="2">
13894 <column alignment="center" valignment="top" leftline="true" width="0">
13895 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
13896 <row topline="true" bottomline="true">
13897 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13914 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13923 <row topline="true">
13924 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13941 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13955 add floating point numbers
13959 <row topline="true">
13960 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
13977 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
13991 subtract floating point numbers
13995 <row topline="true">
13996 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14013 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14027 divide floating point numbers
14031 <row topline="true">
14032 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14049 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14063 multiply floating point numbers
14067 <row topline="true">
14068 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14085 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14099 convert floating point to unsigned char
14103 <row topline="true">
14104 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14121 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14135 convert floating point to signed char
14139 <row topline="true">
14140 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14157 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14171 convert floating point to unsigned int
14175 <row topline="true">
14176 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14193 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14207 convert floating point to signed int
14211 <row topline="true">
14212 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14238 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14252 convert floating point to unsigned long
14256 <row topline="true">
14257 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14274 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14288 convert floating point to signed long
14292 <row topline="true">
14293 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14310 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14324 convert unsigned char to floating point
14328 <row topline="true">
14329 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14346 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14360 convert char to floating point number
14364 <row topline="true">
14365 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14382 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14396 convert unsigned int to floating point
14400 <row topline="true">
14401 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14418 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14432 convert int to floating point numbers
14436 <row topline="true">
14437 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14454 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14468 convert unsigned long to floating point number
14472 <row topline="true" bottomline="true">
14473 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
14490 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
14504 convert long to floating point number
14517 These support routines are developed in ANSI-C so there is room for space
14518 and speed improvement
14524 The floating point routines for the mcs51 are implemented in assembler
14528 Note if all these routines are used simultaneously the data space might
14530 For serious floating point usage the large model might be needed.
14531 Also notice that you don't have to call this routines directly.
14532 The compiler will use them automatically every time a floating point operation
14537 \begin_inset LatexCommand \index{Libraries}
14546 <pending: this is messy and incomplete - a little more information is in
14547 sdcc/doc/libdoc.txt
14552 Compiler support routines (_gptrget, _mulint etc.)
14555 Stdclib functions (puts, printf, strcat etc.)
14556 \layout Subsubsection
14562 \begin_inset LatexCommand \index{<stdio.h>}
14566 As usual on embedded systems you have to provide your own
14569 \begin_inset LatexCommand \index{getchar()}
14578 \begin_inset LatexCommand \index{putchar()}
14585 SDCC does not know whether the system connects to a serial line with or
14586 without handshake, LCD, keyboard or other device.
14587 You'll find examples for serial routines f.e.
14588 in sdcc/device/lib.
14594 \begin_inset LatexCommand \index{printf()}
14604 does not support float (except on ds390).
14605 To enable this recompile it with the option
14618 \begin_inset LatexCommand \index{USE\_FLOATS}
14624 on the command line.
14638 \begin_inset LatexCommand \index{-\/-model-large}
14644 for the mcs51 port, since this uses a lot of memory.
14647 If you're short on memory you might want to use
14650 \begin_inset LatexCommand \index{printf\_small()}
14665 For the mcs51 there additionally are assembly versions
14668 \begin_inset LatexCommand \index{printf\_tiny() (mcs51)}
14677 \begin_inset LatexCommand \index{printf\_fast() (mcs51)}
14686 \begin_inset LatexCommand \index{printf\_fast\_f() (mcs51)}
14692 which should fit the requirements of many embedded systems (printf_fast()
14693 can be customized by unsetting #defines to
14697 support long variables and field widths).
14700 Math functions (sin, pow, sqrt etc.)
14707 \begin_inset LatexCommand \index{Libraries}
14711 included in SDCC should have a license at least as liberal as the GNU Lesser
14712 General Public License
14713 \begin_inset LatexCommand \index{GNU Lesser General Public License, LGPL}
14724 license statements for the libraries are missing.
14725 sdcc/device/lib/ser_ir.c
14729 come with a GPL (as opposed to LGPL) License - this will not be liberal
14730 enough for many embedded programmers.
14733 If you have ported some library or want to share experience about some code
14735 falls into any of these categories Busses (I
14736 \begin_inset Formula $^{\textrm{2}}$
14739 C, CAN, Ethernet, Profibus, Modbus, USB, SPI, JTAG ...), Media (IDE, Memory
14740 cards, eeprom, flash...), En-/Decryption, Remote debugging, Realtime kernel,
14741 Keyboard, LCD, RTC, FPGA, PID then the sdcc-user mailing list
14742 \begin_inset LatexCommand \url{http://sourceforge.net/mail/?group_id=599}
14747 would certainly like to hear about it.
14748 Programmers coding for embedded systems are not especially famous for being
14749 enthusiastic, so don't expect a big hurray but as the mailing list is searchabl
14750 e these references are very valuable.
14751 Let's help to create a climate where information is shared.
14757 MCS51 Memory Models
14758 \begin_inset LatexCommand \index{Memory model}
14763 \begin_inset LatexCommand \index{MCS51 memory model}
14768 \layout Subsubsection
14770 Small, Medium and Large
14773 SDCC allows three memory models for MCS51 code,
14782 Modules compiled with different memory models should
14786 be combined together or the results would be unpredictable.
14787 The library routines supplied with the compiler are compiled as small,
14789 The compiled library modules are contained in separate directories as small,
14790 medium and large so that you can link to the appropriate set.
14793 When the medium or large model is used all variables declared without a
14794 storage class will be allocated into the external ram, this includes all
14795 parameters and local variables (for non-reentrant
14796 \begin_inset LatexCommand \index{reentrant}
14801 When the small model is used variables without storage class are allocated
14802 in the internal ram.
14805 Judicious usage of the processor specific storage classes
14806 \begin_inset LatexCommand \index{Storage class}
14810 and the 'reentrant' function type will yield much more efficient code,
14811 than using the large model.
14812 Several optimizations are disabled when the program is compiled using the
14813 large model, it is therefore recommended that the small model be used unless
14814 absolutely required.
14815 \layout Subsubsection
14818 \begin_inset LatexCommand \label{sub:External-Stack}
14823 \begin_inset LatexCommand \index{stack}
14828 \begin_inset LatexCommand \index{External stack (mcs51)}
14835 The external stack (-
14846 \begin_inset LatexCommand \index{-\/-xstack}
14850 ) is located in pdata
14851 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
14855 memory (usually at the start of the external ram segment) and uses all
14856 unused space in pdata (max.
14868 -xstack option is used to compile the program, the parameters and local
14870 \begin_inset LatexCommand \index{local variables}
14874 of all reentrant functions are allocated in this area.
14875 This option is provided for programs with large stack space requirements.
14876 When used with the -
14887 \begin_inset LatexCommand \index{-\/-stack-auto}
14891 option, all parameters and local variables are allocated on the external
14892 stack (note: support libraries will need to be recompiled with the same
14894 There is a predefined target in the library makefile).
14897 The compiler outputs the higher order address byte of the external ram segment
14899 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
14904 \begin_inset LatexCommand \ref{sub:MCS51-variants}
14908 ), therefore when using the External Stack option, this port
14912 be used by the application program.
14916 \begin_inset LatexCommand \index{Memory model}
14921 \begin_inset LatexCommand \index{DS390 memory model}
14928 The only model supported is Flat 24
14929 \begin_inset LatexCommand \index{Flat 24 (DS390 memory model)}
14934 This generates code for the 24 bit contiguous addressing mode of the Dallas
14936 In this mode, up to four meg of external RAM or code space can be directly
14938 See the data sheets at www.dalsemi.com for further information on this part.
14942 Note that the compiler does not generate any code to place the processor
14943 into 24 bitmode (although
14947 in the ds390 libraries will do that for you).
14953 \begin_inset LatexCommand \index{Tinibios (DS390)}
14957 , the boot loader or similar code must ensure that the processor is in 24
14958 bit contiguous addressing mode before calling the SDCC startup code.
14976 option, variables will by default be placed into the XDATA segment.
14981 Segments may be placed anywhere in the 4 meg address space using the usual
14993 Note that if any segments are located above 64K, the -r flag must be passed
14994 to the linker to generate the proper segment relocations, and the Intel
14995 HEX output format must be used.
14996 The -r flag can be passed to the linker by using the option
15000 on the SDCC command line.
15001 However, currently the linker can not handle code segments > 64k.
15005 \begin_inset LatexCommand \index{Pragmas}
15012 SDCC supports the following #pragma directives:
15016 \begin_inset LatexCommand \index{\#pragma save}
15020 - this will save all current options to the save/restore stack.
15021 See #pragma\SpecialChar ~
15026 \begin_inset LatexCommand \index{\#pragma restore}
15030 - will restore saved options from the last save.
15031 saves & restores can be nested.
15032 SDCC uses a save/restore stack: save pushes current options to the stack,
15033 restore pulls current options from the stack.
15034 See #pragma\SpecialChar ~
15041 \begin_inset LatexCommand \index{\#pragma callee\_saves}
15046 \begin_inset LatexCommand \index{function prologue}
15050 function1[,function2[,function3...]] - The compiler by default uses a caller
15051 saves convention for register saving across function calls, however this
15052 can cause unnecessary register pushing & popping
15053 \begin_inset LatexCommand \index{push/pop}
15057 when calling small functions from larger functions.
15058 This option can be used to switch off the register saving convention for
15059 the function names specified.
15060 The compiler will not save registers when calling these functions, extra
15061 code need to be manually inserted at the entry & exit for these functions
15062 to save & restore the registers used by these functions, this can SUBSTANTIALLY
15063 reduce code & improve run time performance of the generated code.
15064 In the future the compiler (with inter procedural analysis) may be able
15065 to determine the appropriate scheme to use for each function call.
15076 -callee-saves command line option is used, the function names specified
15077 in #pragma\SpecialChar ~
15079 \begin_inset LatexCommand \index{\#pragma callee\_saves}
15083 is appended to the list of functions specified in the command line.
15087 \begin_inset LatexCommand \index{\#pragma exclude}
15091 none | {acc[,b[,dpl[,dph]]] - The exclude pragma disables the generation
15092 of pairs of push/pop
15093 \begin_inset LatexCommand \index{push/pop}
15102 \begin_inset LatexCommand \index{interrupt}
15115 The directive should be placed immediately before the ISR function definition
15116 and it affects ALL ISR functions following it.
15117 To enable the normal register saving for ISR functions use #pragma\SpecialChar ~
15118 exclude\SpecialChar ~
15120 \begin_inset LatexCommand \index{\#pragma exclude}
15125 See also the related keyword _naked
15126 \begin_inset LatexCommand \index{\_naked}
15131 \begin_inset LatexCommand \index{\_\_naked}
15139 \begin_inset LatexCommand \index{\#pragma less\_pedantic}
15143 - the compiler will not warn you anymore for obvious mistakes, you'r on
15147 disable_warning <nnnn>
15148 \begin_inset LatexCommand \index{\#pragma disable\_warning}
15152 - the compiler will not warn you anymore about warning number <nnnn>.
15156 \begin_inset LatexCommand \index{\#pragma nogcse}
15160 - will stop global common subexpression elimination.
15164 \begin_inset LatexCommand \index{\#pragma noinduction}
15168 - will stop loop induction optimizations.
15172 \begin_inset LatexCommand \index{\#pragma noinvariant}
15176 - will not do loop invariant optimizations.
15177 For more details see Loop Invariants in section
15178 \begin_inset LatexCommand \ref{sub:Loop-Optimizations}
15186 \begin_inset LatexCommand \index{\#pragma noiv}
15190 - Do not generate interrupt
15191 \begin_inset LatexCommand \index{interrupt}
15195 vector table entries for all ISR functions defined after the pragma.
15196 This is useful in cases where the interrupt vector table must be defined
15197 manually, or when there is a secondary, manually defined interrupt vector
15199 for the autovector feature of the Cypress EZ-USB FX2).
15200 More elegantly this can be achieved by obmitting the optional interrupt
15201 number after the interrupt keyword, see section
15202 \begin_inset LatexCommand \ref{sub:Interrupt-Service-Routines}
15211 \begin_inset LatexCommand \index{\#pragma nojtbound}
15215 - will not generate code for boundary value checking, when switch statements
15216 are turned into jump-tables (dangerous).
15217 For more details see section
15218 \begin_inset LatexCommand \ref{sub:'switch'-Statements}
15226 \begin_inset LatexCommand \index{\#pragma noloopreverse}
15230 - Will not do loop reversal optimization
15234 \begin_inset LatexCommand \index{\#pragma nooverlay}
15238 - the compiler will not overlay the parameters and local variables of a
15243 \begin_inset LatexCommand \index{\#pragma stackauto}
15258 \begin_inset LatexCommand \index{-\/-stack-auto}
15263 \begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
15267 Parameters and Local Variables.
15271 \begin_inset LatexCommand \index{\#pragma opt\_code\_speed}
15275 - The compiler will optimize code generation towards fast code, possibly
15276 at the expense of code size.
15280 \begin_inset LatexCommand \index{\#pragma opt\_code\_size}
15284 - The compiler will optimize code generation towards compact code, possibly
15285 at the expense of code speed.
15289 \begin_inset LatexCommand \index{\#pragma opt\_code\_balanced}
15293 - The compiler will attempt to generate code that is both compact and fast,
15294 as long as meeting one goal is not a detriment to the other (this is the
15300 \begin_inset LatexCommand \index{\#pragma std\_sdcc89}
15304 - Generally follow the C89 standard, but allow SDCC features that conflict
15305 with the standard (default).
15309 \begin_inset LatexCommand \index{\#pragma std\_c89}
15313 - Follow the C89 standard and disable SDCC features that conflict with the
15318 \begin_inset LatexCommand \index{\#pragma std\_sdcc99}
15322 - Generally follow the C99 standard, but allow SDCC features that conflict
15323 with the standard (incomplete support).
15327 \begin_inset LatexCommand \index{\#pragma std\_c99}
15331 - Follow the C99 standard and disable SDCC features that conflict with the
15332 standard (incomplete support).
15336 \begin_inset LatexCommand \index{\#pragma codeseg}
15340 - Use this name (max.
15341 8 characters) for the code segment.
15345 \begin_inset LatexCommand \index{\#pragma constseg}
15349 - Use this name (max.
15350 8 characters) for the const segment.
15353 SDCPP supports the following #pragma directives:
15357 \begin_inset LatexCommand \index{\#pragma preproc\_asm}
15361 (+ | -) - switch _asm _endasm block preprocessing on / off.
15365 The pragma's are intended to be used to turn-on or off certain optimizations
15366 which might cause the compiler to generate extra stack / data space to
15367 store compiler generated temporary variables.
15368 This usually happens in large functions.
15369 Pragma directives should be used as shown in the following example, they
15370 are used to control options & optimizations for a given function; pragmas
15371 should be placed before and/or after a function, placing pragma's inside
15372 a function body could have unpredictable results.
15378 \begin_inset LatexCommand \index{\#pragma save}
15389 /* save the current settings */
15392 \begin_inset LatexCommand \index{\#pragma nogcse}
15401 /* turnoff global subexpression elimination */
15403 #pragma noinduction
15404 \begin_inset LatexCommand \index{\#pragma noinduction}
15408 /* turn off induction optimizations */
15431 \begin_inset LatexCommand \index{\#pragma restore}
15435 /* turn the optimizations back on */
15438 The compiler will generate a warning message when extra space is allocated.
15439 It is strongly recommended that the save and restore pragma's be used when
15440 changing options for a function.
15443 Defines Created by the Compiler
15446 The compiler creates the following #defines
15447 \begin_inset LatexCommand \index{\#defines}
15452 \begin_inset LatexCommand \index{Defines created by the compiler}
15462 \begin_inset Tabular
15463 <lyxtabular version="3" rows="11" columns="2">
15465 <column alignment="center" valignment="top" leftline="true" width="0">
15466 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
15467 <row topline="true" bottomline="true">
15468 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15478 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15489 <row topline="true">
15490 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15496 \begin_inset LatexCommand \index{SDCC}
15503 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15508 this Symbol is always defined
15512 <row topline="true">
15513 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15519 \begin_inset LatexCommand \index{SDCC\_mcs51}
15524 \begin_inset LatexCommand \index{SDCC\_ds390}
15529 \begin_inset LatexCommand \index{SDCC\_z80}
15536 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15541 depending on the model used (e.g.: -mds390
15545 <row topline="true">
15546 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15552 \begin_inset LatexCommand \index{\_\_mcs51}
15557 \begin_inset LatexCommand \index{\_\_ds390}
15562 \begin_inset LatexCommand \index{\_\_hc08}
15567 \begin_inset LatexCommand \index{\_\_z80}
15574 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15579 depending on the model used (e.g.
15584 <row topline="true">
15585 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15591 \begin_inset LatexCommand \index{SDCC\_STACK\_AUTO}
15598 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15621 <row topline="true">
15622 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15628 \begin_inset LatexCommand \index{SDCC\_MODEL\_SMALL}
15635 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15658 <row topline="true">
15659 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15665 \begin_inset LatexCommand \index{SDCC\_MODEL\_MEDIUM}
15672 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15695 <row topline="true">
15696 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15702 \begin_inset LatexCommand \index{SDCC\_MODEL\_LARGE}
15709 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15732 <row topline="true">
15733 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15739 \begin_inset LatexCommand \index{SDCC\_USE\_XSTACK}
15746 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15769 <row topline="true">
15770 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15776 \begin_inset LatexCommand \index{SDCC\_STACK\_TENBIT}
15783 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15796 <row topline="true" bottomline="true">
15797 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
15803 \begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
15810 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
15830 Notes on supported Processors
15834 \begin_inset LatexCommand \label{sub:MCS51-variants}
15839 \begin_inset LatexCommand \index{MCS51 variants}
15846 MCS51 processors are available from many vendors and come in many different
15848 While they might differ considerably in respect to Special Function Registers
15849 the core MCS51 is usually not modified or is kept compatible.
15853 pdata access by SFR
15856 With the upcome of devices with internal xdata and flash memory devices
15858 \begin_inset LatexCommand \index{P2 (mcs51 sfr)}
15862 as dedicated I/O port is becoming more popular.
15863 Switching the high byte for pdata
15864 \begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
15868 access which was formerly done by port P2 is then achieved by a Special
15870 \begin_inset LatexCommand \index{sfr}
15875 In well-established MCS51 tradition the address of this
15879 is where the chip designers decided to put it.
15880 Needless to say that they didn't agree on a common name either.
15881 So that the startup code can correctly initialize xdata variables, you
15882 should define an sfr with the name _XPAGE
15885 \begin_inset LatexCommand \index{\_XPAGE (mcs51)}
15891 at the appropriate location if the default, port P2, is not used for this.
15897 sfr at 0x92 _XPAGE; /* Cypress EZ-USB family */
15902 sfr at 0xaf _XPAGE; /* some Silicon Labs (Cygnal) chips */
15907 sfr at 0xaa _XPAGE; /* some Silicon Labs (Cygnal) chips */
15910 For more exotic implementations further customizations may be needed.
15912 \begin_inset LatexCommand \ref{sub:Startup-Code}
15916 for other possibilities.
15919 Other Features available by SFR
15922 Some MCS51 variants offer features like Double DPTR
15923 \begin_inset LatexCommand \index{DPTR}
15927 , multiple DPTR, decrementing DPTR, 16x16 Multiply.
15928 These are currently not used for the MCS51 port.
15929 If you absolutely need them you can fall back to inline assembly or submit
15936 The DS80C400 microcontroller has a rich set of peripherals.
15937 In its built-in ROM library it includes functions to access some of the
15938 features, among them is a TCP stack with IP4 and IP6 support.
15939 Library headers (currently in beta status) and other files are provided
15943 \begin_inset LatexCommand \url{ftp://ftp.dalsemi.com/pub/tini/ds80c400/c_libraries/sdcc/index.html}
15951 The Z80 and gbz80 port
15954 SDCC can target both the Zilog
15955 \begin_inset LatexCommand \index{Z80}
15959 and the Nintendo Gameboy's Z80-like gbz80
15960 \begin_inset LatexCommand \index{gbz80 (GameBoy Z80)}
15965 The Z80 port is passed through the same
15968 \begin_inset LatexCommand \index{Regression test}
15974 as the MCS51 and DS390 ports, so floating point support, support for long
15975 variables and bitfield support is fine.
15976 See mailing lists and forums about interrupt routines.
15979 As always, the code is the authoritative reference - see z80/ralloc.c and
15982 \begin_inset LatexCommand \index{stack}
15986 frame is similar to that generated by the IAR Z80 compiler.
15987 IX is used as the base pointer, HL and IY are used as a temporary registers,
15988 and BC and DE are available for holding variables.
15990 \begin_inset LatexCommand \index{return value}
15994 for the Z80 port are stored in L (one byte), HL (two bytes), or DEHL (four
15996 The gbz80 port use the same set of registers for the return values, but
15997 in a different order of significance: E (one byte), DE (two bytes), or
16004 The port to the Motorola HC08
16005 \begin_inset LatexCommand \index{HC08}
16009 family has been added in October 2003, and is still undergoing some basic
16011 The code generator is complete, but the register allocation is still quite
16013 Some of the SDCC's standard C library functions have embedded non-HC08
16014 inline assembly and so are not yet usable.
16025 \begin_inset LatexCommand \index{PIC14}
16029 port still requires a major effort from the development community.
16030 However it can work for very simple code.
16033 C code and 14bit PIC code page
16034 \begin_inset LatexCommand \index{code page (pic14)}
16039 \begin_inset LatexCommand \index{RAM bank (pic14)}
16046 The linker organizes allocation for the code page and RAM banks.
16047 It does not have intimate knowledge of the code flow.
16048 It will put all the code section of a single asm file into a single code
16050 In order to make use of multiple code pages, separate asm files must be
16052 The compiler treats all functions of a single C file as being in the same
16053 code page unless it is non static.
16054 The compiler treats all local variables of a single C file as being in
16055 the same RAM bank unless it is an extern.
16059 To get the best follow these guide lines:
16062 make local functions static, as non static functions require code page selection
16066 Make local variables static as extern variables require RAM bank selection
16070 For devices that have multiple code pages it is more efficient to use the
16071 same number of files as pages, i.e.
16072 for the 16F877 use 4 separate files and i.e.
16073 for the 16F874 use 2 separate files.
16074 This way the linker can put the code for each file into different code
16075 pages and the compiler can allocate reusable variables more efficiently
16076 and there's less page selection overhead.
16077 And as for any 8 bit micro (especially for PIC 14 as they have a very simple
16078 instruction set) use 'unsigned char' whereever possible instead of 'int'.
16081 Creating a device include file
16084 For generating a device include file use the support perl script inc2h.pl
16085 kept in directory support/script.
16091 For the interrupt function, use the keyword 'interrupt'
16092 \begin_inset LatexCommand \index{interrupt}
16096 with level number of 0 (PIC14 only has 1 interrupt so this number is only
16097 there to avoid a syntax error - it ought to be fixed).
16103 void Intr(void) interrupt 0
16109 T0IF = 0; /* Clear timer interrupt */
16114 Linking and assembling
16117 For assembling you can use either GPUTILS'
16118 \begin_inset LatexCommand \index{gputils (pic tools)}
16122 gpasm.exe or MPLAB's mpasmwin.exe.
16123 GPUTILS is available from
16124 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
16129 For linking you can use either GPUTIL's gplink or MPLAB's mplink.exe.
16130 If you use MPLAB and an interrupt function then the linker script file
16131 vectors section will need to be enlarged to link with mplink.
16154 sdcc -S -V -mpic14 -p16F877 $<
16168 $(PRJ).hex: $(OBJS)
16178 gplink -m -s $(PRJ).lkr -o $(PRJ).hex $(OBJS) libsdcc.lib
16200 sdcc -S -V -mpic14 -p16F877 $<
16210 mpasmwin /q /o $*.asm
16214 $(PRJ).hex: $(OBJS)
16224 mplink /v $(PRJ).lkr /m $(PRJ).map /o $(PRJ).hex $(OBJS) libsdcc.lib
16227 Please note that indentations within a
16231 have to be done with a tabulator character.
16234 Command-line options
16237 Besides the switches common to all SDCC backends, the PIC14 port accepts
16238 the following options (for an updated list see sdcc -
16250 \labelwidthstring 00.00.0000
16262 -debug-extra emit debug info in assembly output
16264 \labelwidthstring 00.00.0000
16276 -no-pcode-opt disable (slightly faulty) optimization on pCode
16280 \layout Subsubsection
16282 error: missing definition for symbol
16283 \begin_inset Quotes sld
16287 \begin_inset Quotes srd
16293 The PIC14 port uses library routines to provide more complex operations
16294 like multiplication, division/modulus and (generic) pointer dereferencing.
16295 In order to add these routines to your project, you must link with PIC14's
16301 For single source file projects this is done automatically, more complex
16306 to the linker's arguments.
16307 Make sure you also add an include path for the library (using the -I switch
16309 \layout Subsubsection
16311 Processor mismatch in file
16312 \begin_inset Quotes sld
16316 \begin_inset Quotes srd
16322 This warning can usually be ignored due to the very good compatibility amongst
16323 14 bit PIC devices.
16326 You might also consider recompiling the library for your specific device
16327 by changing the ARCH=p16f877 (default target) entry in
16329 device/lib/pic/Makefile.in
16333 device/lib/pic/Makefile
16335 to reflect your device.
16336 This might even improve performance for smaller devices as unneccesary
16337 BANKSELs migth be removed.
16341 \layout Subsubsection
16346 Currently, data can only be initialized if it resides in the source file
16352 Data in other source files will silently
16360 \begin_inset LatexCommand \index{PIC16}
16368 \begin_inset LatexCommand \index{PIC16}
16372 port is the portion of SDCC that is responsible to produce code for the
16374 \begin_inset LatexCommand \index{Microchip}
16378 (TM) microcontrollers with 16 bit core.
16379 Currently this family of microcontrollers contains the PIC18Fxxx and PIC18Fxxxx.
16380 Currently supported devices are:
16384 \begin_inset Tabular
16385 <lyxtabular version="3" rows="4" columns="6">
16387 <column alignment="center" valignment="top" leftline="true" width="0">
16388 <column alignment="center" valignment="top" leftline="true" width="0">
16389 <column alignment="center" valignment="top" leftline="true" width="0">
16390 <column alignment="center" valignment="top" leftline="true" width="0">
16391 <column alignment="center" valignment="top" leftline="true" width="0">
16392 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
16393 <row topline="true">
16394 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16402 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16410 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16418 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16426 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16434 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16443 <row topline="true">
16444 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16452 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16460 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16468 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16476 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16484 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16493 <row topline="true">
16494 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16502 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16510 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16518 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16526 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16534 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16543 <row topline="true" bottomline="true">
16544 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16552 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16560 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
16568 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16575 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16582 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
16600 PIC16 port supports the standard command line arguments as supposed, with
16601 the exception of certain cases that will be mentioned in the following
16604 \labelwidthstring 00.00.0000
16616 -callee-saves See -
16628 \labelwidthstring 00.00.0000
16640 -all-callee-saves All function arguments are passed on stack by default.
16643 There is no need to specify this in the command line.
16645 \labelwidthstring 00.00.0000
16657 -fommit-frame-pointer Frame pointer will be omitted when the function uses
16658 no local variables.
16661 Port Specific Options
16662 \begin_inset LatexCommand \index{Options PIC16}
16669 The port specific options appear after the global options in the sdcc --help
16671 \layout Subsubsection
16676 General options enable certain port features and optimizations.
16678 \labelwidthstring 00.00.0000
16690 -stack-model=[model] Used in conjuction with the command above.
16691 Defines the stack model to be used, valid stack models are :
16694 \labelwidthstring 00.00.0000
16700 Selects small stack model.
16701 8 bit stack and frame pointers.
16702 Supports 256 bytes stack size.
16704 \labelwidthstring 00.00.0000
16710 Selects large stack model.
16711 16 bit stack and frame pointers.
16712 Supports 65536 bytes stack size.
16715 \labelwidthstring 00.00.0000
16727 -preplace-udata-with=[kword] Replaces the default udata keyword for allocating
16728 unitialized data variables with [kword].
16729 Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
16731 \labelwidthstring 00.00.0000
16743 -ivt-loc <nnnn> positions the Interrupt Vector Table at location <nnnn>.
16744 Useful for bootloaders.
16746 \labelwidthstring 00.00.0000
16758 -asm= sets the full path and name of an external assembler to call.
16760 \labelwidthstring 00.00.0000
16772 -link= sets the full path and name of an external linker to call.
16774 \labelwidthstring 00.00.0000
16786 -mplab-comp MPLAB compatibility option.
16787 Currently only suppresses special gpasm directives.
16788 \layout Subsubsection
16790 Optimization Options
16792 \labelwidthstring 00.00.0000
16804 -optimize-goto Try to use (conditional) BRA instead of GOTO
16806 \labelwidthstring 00.00.0000
16818 -optimize-cmp Try to optimize some compares.
16820 \labelwidthstring 00.00.0000
16832 -optimize-df Analyze the dataflow of the generated code and improve it.
16834 \labelwidthstring 00.00.0000
16846 -obanksel=nn Set optimization level for inserting BANKSELs.
16851 \labelwidthstring 00.00.0000
16855 \labelwidthstring 00.00.0000
16857 1 checks previous used register and if it is the same then does not emit
16858 BANKSEL, accounts only for labels.
16860 \labelwidthstring 00.00.0000
16862 2 tries to check the location of (even different) symbols and removes BANKSELs
16863 if they are in the same bank.
16868 Important: There might be problems if the linker script has data sections
16869 across bank borders!
16871 \layout Subsubsection
16875 \labelwidthstring 00.00.0000
16887 -nodefaultlibs do not link default libraries when linking
16889 \labelwidthstring 00.00.0000
16901 -no-crt Don't link the default run-time modules
16903 \labelwidthstring 00.00.0000
16915 -use-crt= Use a custom run-time module instead of the defaults.
16916 \layout Subsubsection
16921 Debugging options enable extra debugging information in the output files.
16923 \labelwidthstring 00.00.0000
16935 -debug-xtra Similar to -
16946 \begin_inset LatexCommand \index{-\/-debug}
16950 , but dumps more information.
16952 \labelwidthstring 00.00.0000
16964 -debug-ralloc Force register allocator to dump <source>.d file with debugging
16966 <source> is the name of the file compiled.
16968 \labelwidthstring 00.00.0000
16980 -pcode-verbose Enable pcode debugging information in translation.
16982 \labelwidthstring 00.00.0000
16994 -denable-peeps Force the usage of peepholes.
16997 \labelwidthstring 00.00.0000
17009 -gstack Trace push/pops for stack pointer overflow
17011 \labelwidthstring 00.00.0000
17023 -call-tree dump call tree in .calltree file
17026 Enviromental Variables
17029 There is a number of enviromental variables that can be used when running
17030 SDCC to enable certain optimizations or force a specific program behaviour.
17031 these variables are primarily for debugging purposes so they can be enabled/dis
17035 Currently there is only two such variables available:
17037 \labelwidthstring 00.00.0000
17039 OPTIMIZE_BITFIELD_POINTER_GET when this variable exists reading of structure
17040 bitfields is optimized by directly loading FSR0 with the address of the
17041 bitfield structure.
17042 Normally SDCC will cast the bitfield structure to a bitfield pointer and
17044 This step saves data ram and code space for functions that perform heavy
17047 80 bytes of code space are saved when compiling malloc.c with this option).
17050 \labelwidthstring 00.00.0000
17052 NO_REG_OPT do not perform pCode registers optimization.
17053 This should be used for debugging purposes.
17054 In some where bugs in the pcode optimizer are found, users can benefit
17055 from temporarily disabling the optimizer until the bug is fixed.
17058 Preprocessor Macros
17061 PIC16 port defines the following preprocessor macros while translating a
17066 \begin_inset Tabular
17067 <lyxtabular version="3" rows="6" columns="2">
17069 <column alignment="center" valignment="top" leftline="true" width="0">
17070 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
17071 <row topline="true" bottomline="true">
17072 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17080 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17089 <row topline="true">
17090 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17098 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17103 Port identification
17107 <row topline="true">
17108 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17126 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17131 Port identification (same as above)
17135 <row topline="true">
17136 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17144 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17149 MCU Identification.
17154 is the microcontrol identification number, i.e.
17159 <row topline="true">
17160 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17178 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17183 MCU Identification (same as above)
17187 <row topline="true" bottomline="true">
17188 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17196 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17201 nnn = SMALL or LARGE respectively according to the stack model used
17212 In addition the following macros are defined when calling assembler:
17216 \begin_inset Tabular
17217 <lyxtabular version="3" rows="4" columns="2">
17219 <column alignment="center" valignment="top" leftline="true" width="0">
17220 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
17221 <row topline="true" bottomline="true">
17222 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17230 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17239 <row topline="true">
17240 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17248 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17253 MCU Identification.
17258 is the microcontrol identification number, i.e.
17263 <row topline="true">
17264 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17272 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17277 nnn = SMALL or LARGE respectively according to the memory model used for
17282 <row topline="true" bottomline="true">
17283 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17291 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17296 nnn = SMALL or LARGE respectively according to the stack model used
17311 \begin_inset LatexCommand \index{PIC16}
17315 port uses the following directories for searching header files and libraries.
17319 \begin_inset Tabular
17320 <lyxtabular version="3" rows="3" columns="4">
17322 <column alignment="center" valignment="top" leftline="true" width="0">
17323 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
17324 <column alignment="center" valignment="top" width="0">
17325 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
17326 <row topline="true" bottomline="true">
17327 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17335 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17343 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17351 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17360 <row topline="true">
17361 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17366 PREFIX/sdcc/include/pic16
17369 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17374 PIC16 specific headers
17377 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17385 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17394 <row topline="true" bottomline="true">
17395 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17400 PREFIX/sdcc/lib/pic16
17403 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17408 PIC16 specific libraries
17411 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17419 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17436 \begin_inset LatexCommand \label{sub:PIC16_Pragmas}
17443 PIC16 port currently supports the following pragmas:
17445 \labelwidthstring 00.00.0000
17447 stack pragma stack forces the code generator to initialize the stack & frame
17448 pointers at a specific address.
17449 This is an adhoc solution for cases where no STACK directive is available
17450 in the linker script or gplink is not instructed to create a stack section.
17452 The stack pragma should be used only once in a project.
17453 Multiple pragmas may result in indeterminate behaviour of the program.
17459 The old format (ie.
17460 #pragma stack 0x5ff) is deprecated and will cause the stack pointer to
17461 cross page boundaries (or even exceed the available data RAM) and crash
17463 Make sure that stack does not cross page boundaries when using the SMALL
17469 The format is as follows:
17472 #pragma stack bottom_address [stack_size]
17479 is the lower bound of the stack section.
17480 The stack pointer initially will point at address (bottom_address+stack_size-1).
17488 /* initializes stack of 100 bytes at RAM address 0x200 */
17491 #pragma stack 0x200 100
17494 If the stack_size field is omitted then a stack is created with the default
17496 This size might be enough for most programs, but its not enough for operations
17497 with deep function nesting or excessive stack usage.
17499 \labelwidthstring 00.00.0000
17503 This pragma is deprecated.
17504 Its use will cause a warning message to be issued.
17510 \labelwidthstring 00.00.0000
17512 code place a function symbol at static FLASH address
17520 /* place function test_func at 0x4000 */
17523 #pragma code test_func 0x4000
17527 \labelwidthstring 00.00.0000
17529 library instructs the linker to use a library module.
17534 #pragma library module_name
17541 can be any library or object file (including its path).
17542 Note that there are four reserved keywords which have special meaning.
17547 \begin_inset Tabular
17548 <lyxtabular version="3" rows="6" columns="3">
17550 <column alignment="center" valignment="top" leftline="true" width="0">
17551 <column alignment="block" valignment="top" leftline="true" width="20page%">
17552 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0">
17553 <row topline="true" bottomline="true">
17554 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17562 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17570 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17579 <row topline="true">
17580 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17590 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17595 ignore all library pragmas
17598 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17609 <row topline="true">
17610 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17620 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17628 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17641 <row topline="true">
17642 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17652 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17657 link the Math libarary
17660 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17673 <row topline="true">
17674 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17684 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17689 link the I/O library
17692 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17705 <row topline="true" bottomline="true">
17706 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17716 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
17721 link the debug library
17724 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
17743 * is the device number, i.e.
17744 452 for PIC18F452 MCU.
17747 This feature allows for linking with specific libraries withoug having to
17748 explicit name them in the command line.
17753 keyword will reject all modules specified by the library pragma.
17755 \labelwidthstring 00.00.0000
17757 udata pragma udata instructs the compiler to emit code so that linker will
17758 place a variable at a specific memory bank
17766 /* places variable foo at bank2 */
17769 #pragma udata bank2 foo
17775 In order for this pragma to work extra SECTION directives should be added
17776 in the .lkr script.
17777 In the following example a sample .lkr file is shown:
17782 // Sample linker script for the PIC18F452 processor
17788 CODEPAGE NAME=vectors START=0x0 END=0x29 PROTECTED
17791 CODEPAGE NAME=page START=0x2A END=0x7FFF
17794 CODEPAGE NAME=idlocs START=0x200000 END=0x200007 PROTECTED
17797 CODEPAGE NAME=config START=0x300000 END=0x30000D PROTECTED
17800 CODEPAGE NAME=devid START=0x3FFFFE END=0x3FFFFF PROTECTED
17803 CODEPAGE NAME=eedata START=0xF00000 END=0xF000FF PROTECTED
17806 ACCESSBANK NAME=accessram START=0x0 END=0x7F
17811 DATABANK NAME=gpr0 START=0x80 END=0xFF
17814 DATABANK NAME=gpr1 START=0x100 END=0x1FF
17817 DATABANK NAME=gpr2 START=0x200 END=0x2FF
17820 DATABANK NAME=gpr3 START=0x300 END=0x3FF
17823 DATABANK NAME=gpr4 START=0x400 END=0x4FF
17826 DATABANK NAME=gpr5 START=0x500 END=0x5FF
17829 ACCESSBANK NAME=accesssfr START=0xF80 END=0xFFF PROTECTED
17834 SECTION NAME=CONFIG ROM=config
17839 SECTION NAME=bank0 RAM=gpr0 # these SECTION directives
17842 SECTION NAME=bank1 RAM=gpr1 # should be added to link
17845 SECTION NAME=bank2 RAM=gpr2 # section name 'bank?' with
17848 SECTION NAME=bank3 RAM=gpr3 # a specific DATABANK name
17851 SECTION NAME=bank4 RAM=gpr4
17854 SECTION NAME=bank5 RAM=gpr5
17857 The linker will recognise the section name set in the pragma statement and
17858 will position the variable at the memory bank set with the RAM field at
17859 the SECTION line in the linker script file.
17863 \begin_inset LatexCommand \label{sub:PIC16_Header-Files}
17870 There is one main header file that can be included to the source files using
17877 This header file contains the definitions for the processor special registers,
17878 so it is necessary if the source accesses them.
17879 It can be included by adding the following line in the beginning of the
17883 #include <pic18fregs.h>
17886 The specific microcontroller is selected within the pic18fregs.h automatically,
17887 so the same source can be used with a variety of devices.
17893 The libraries that PIC16
17894 \begin_inset LatexCommand \index{PIC16}
17898 port depends on are the microcontroller device libraries which contain
17899 the symbol definitions for the microcontroller special function registers.
17900 These libraries have the format pic18fxxxx.lib, where
17904 is the microcontroller identification number.
17905 The specific library is selected automatically by the compiler at link
17906 stage according to the selected device.
17909 Libraries are created with gplib which is part of the gputils package
17910 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
17915 \layout Subsubsection*
17917 Building the libraries
17920 Before using SDCC/pic16 there are some libraries that need to be compiled.
17921 This process is not done automatically by SDCC since not all users use
17922 SDCC for pic16 projects.
17923 So each user should compile the libraries separately.
17926 The steps to compile the pic16 libraries under Linux are:
17929 cd device/lib/pic16
17944 su -c 'make install' # install the libraries, you need the root password
17947 If you need to install the headers too, do:
17953 su -c 'make install' # install the headers, you need the root password
17956 There exist a special target to build the I/O libraries.
17957 This target is not automatically build because it will build the I/O library
17963 This way building will take quite a lot of time.
17964 Users are advised to edit the
17966 device/lib/pic16/pics.build
17968 file and then execute:
17977 The following memory models are supported by the PIC16 port:
17986 Memory model affects the default size of pointers within the source.
17987 The sizes are shown in the next table:
17991 \begin_inset Tabular
17992 <lyxtabular version="3" rows="3" columns="3">
17994 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
17995 <column alignment="center" valignment="top" leftline="true" width="0">
17996 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
17997 <row topline="true" bottomline="true">
17998 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18003 Pointer sizes according to memory model
18006 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18014 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18023 <row topline="true" bottomline="true">
18024 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18032 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18040 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18049 <row topline="true" bottomline="true">
18050 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18058 <cell multicolumn="1" alignment="center" valignment="top" topline="true" bottomline="true" leftline="true" usebox="none">
18066 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18082 It is advisable that all sources within a project are compiled with the
18084 If one wants to override the default memory model, this can be done by
18085 declaring a pointer as
18094 Far selects large memory model's pointers, while near selects small memory
18098 The standard device libraries (see
18099 \begin_inset LatexCommand \ref{sub:PIC16_Header-Files}
18103 ) contain no reference to pointers, so they can be used with both memory
18110 The stack implementation for the PIC16 port uses two indirect registers,
18113 \labelwidthstring 00.00.0000
18115 FSR1 is assigned as stack pointer
18117 \labelwidthstring 00.00.0000
18119 FSR2 is assigned as frame pointer
18122 The following stack models are supported by the PIC16 port
18143 model means that only the FSRxL byte is used to access stack and frame,
18150 uses both FSRxL and FSRxH registers.
18151 The following table shows the stack/frame pointers sizes according to stack
18152 model and the maximum space they can address:
18156 \begin_inset Tabular
18157 <lyxtabular version="3" rows="3" columns="3">
18159 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18160 <column alignment="center" valignment="top" leftline="true" width="0">
18161 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18162 <row topline="true" bottomline="true">
18163 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18168 Stack & Frame pointer sizes according to stack model
18171 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18179 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18188 <row topline="true">
18189 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18197 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18205 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18214 <row topline="true" bottomline="true">
18215 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18223 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18231 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18251 stack model is currently not working properly throughout the code generator.
18252 So its use is not advised.
18253 Also there are some other points that need special care:
18258 Do not create stack sections with size more than one physical bank (that
18262 Stack sections should no cross physical bank limits (i.e.
18263 #pragma stack 0x50 0x100)
18266 These limitations are caused by the fact that only FSRxL is modified when
18267 using SMALL stack model, so no more than 256 bytes of stack can be used.
18268 This problem will disappear after LARGE model is fully implemented.
18274 In addition to the standard SDCC function keywords, PIC16 port makes available
18277 \labelwidthstring 00.00.0000
18279 wparam Use the WREG to pass one byte of the first function argument.
18280 This improves speed but you may not use this for functions with arguments
18281 that are called via function pointers, otherwise the first byte of the
18282 first parameter will get lost.
18286 void func_wparam(int a) wparam
18292 /* WREG hold the lower part of a */
18295 /* the high part of a is stored in FSR2+2 (or +3 for large stack model)
18305 This keyword replaces the deprecated wparam pragma.
18307 \labelwidthstring 00.00.0000
18309 shadowregs When entering/exiting an ISR, it is possible to take advantage
18310 of the PIC18F hardware shadow registers which hold the values of WREG,
18311 STATUS and BSR registers.
18312 This can be done by adding the keyword
18320 keyword in the function's header.
18323 void isr_shadow(void) shadowregs interrupt 1
18339 instructs the code generator not to store/restore WREG, STATUS, BSR when
18340 entering/exiting the ISR.
18343 Function return values
18346 Return values from functions are placed to the appropriate registers following
18347 a modified Microchip policy optimized for SDCC.
18348 The following table shows these registers:
18352 \begin_inset Tabular
18353 <lyxtabular version="3" rows="6" columns="2">
18355 <column alignment="center" valignment="top" leftline="true" width="0">
18356 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18357 <row topline="true" bottomline="true">
18358 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18366 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18371 destination register
18375 <row topline="true">
18376 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18384 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18393 <row topline="true">
18394 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18402 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18411 <row topline="true">
18412 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18420 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18429 <row topline="true">
18430 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18438 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18443 FSR0L:PRODH:PRODL:WREG
18447 <row topline="true" bottomline="true">
18448 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18456 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18461 on stack, FSR0 points to the beginning
18475 An interrupt servive routine (ISR) is declared using the
18482 void isr(void) interrupt
18500 is the interrupt number, which for PIC18F devices can be:
18504 \begin_inset Tabular
18505 <lyxtabular version="3" rows="4" columns="3">
18507 <column alignment="center" valignment="top" leftline="true" width="0">
18508 <column alignment="center" valignment="top" leftline="true" width="0">
18509 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18510 <row topline="true" bottomline="true">
18511 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18521 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18529 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18534 Interrupt Vector Address
18538 <row topline="true">
18539 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18547 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18555 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18564 <row topline="true">
18565 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18582 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18596 HIGH priority interrupts
18599 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18608 <row topline="true" bottomline="true">
18609 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18617 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18622 LOW priority interrupts
18625 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18641 When generating assembly code for ISR the code generator places a
18647 Interrupt Vector Address
18649 which points at the genetated ISR.
18650 This single GOTO instruction is part of an automatically generated
18652 interrupt entry point
18655 The actuall ISR code is placed as normally would in the code space.
18656 Upon interrupt request, the GOTO instruction is executed which jumps to
18658 When declaring interrupt functions as _naked this GOTO instruction is
18663 The whole interrupt functions is therefore placed at the Interrupt Vector
18664 Address of the specific interrupt.
18665 This is not a problem for the LOW priority interrupts, but it is a problem
18666 for the RESET and the HIGH priority interrupts because code may be written
18667 at the next interrupt´s vector address and cause undeterminate program
18668 behaviour if that interrupt is raised.
18674 This is not a problem when
18677 this is a HIGH interrupt ISR and LOW interrupts are
18684 when the ISR is small enough not to reach the next interrupt´s vector address.
18694 is possible to be omitted.
18695 This way a function is generated similar to an ISR, but it is not assigned
18699 When entering an interrupt, currently the PIC16
18700 \begin_inset LatexCommand \index{PIC16}
18704 port automatically saves the following registers:
18716 PROD (PRODL and PRODH)
18719 FSR0 (FSR0L and FSR0H)
18722 These registers are restored upon return from the interrupt routine.
18728 NOTE that when the _naked attribute is specified for an interrupt routine,
18729 then NO registers are stored or restored.
18738 Generic pointers are implemented in PIC16 port as 3-byte (24-bit) types.
18739 There are 3 types of generic pointers currently implemented data, code
18740 and eeprom pointers.
18741 They are differentiated by the value of the 7th and 6th bits of the upper
18746 \begin_inset Tabular
18747 <lyxtabular version="3" rows="5" columns="5">
18749 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18750 <column alignment="center" valignment="top" width="0">
18751 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
18752 <column alignment="center" valignment="top" width="0">
18753 <column alignment="left" valignment="top" rightline="true" width="0">
18754 <row topline="true" bottomline="true">
18755 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18763 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18771 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18779 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18784 rest of the pointer
18787 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18796 <row topline="true" bottomline="true">
18797 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18805 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18813 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18821 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18830 uuuuuu uuuuxxxx xxxxxxxx
18833 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18838 a 12-bit data pointer in data RAM memory
18842 <row bottomline="true">
18843 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18851 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18859 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18867 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18876 uxxxxx xxxxxxxx xxxxxxxx
18879 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18884 a 21-bit code pointer in FLASH memory
18888 <row bottomline="true">
18889 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18897 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18905 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18913 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18922 uuuuuu uuuuuuxx xxxxxxxx
18925 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18930 a 10-bit eeprom pointer in EEPROM memory
18934 <row bottomline="true">
18935 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18943 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
18951 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18959 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18968 xxxxxx xxxxxxxx xxxxxxxx
18971 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
18976 unimplemented pointer type
18987 Generic pointer are read and written with a set of library functions which
18988 read/write 1, 2, 3, 4 bytes.
18992 \layout Subsubsection
18994 Standard I/O Streams
19001 the type FILE is defined as:
19004 typedef char * FILE;
19007 This type is the stream type implemented I/O in the PIC18F devices.
19008 Also the standard input and output streams are declared in stdio.h:
19011 extern FILE * stdin;
19014 extern FILE * stdout;
19017 The FILE type is actually a generic pointer which defines one more type
19018 of generic pointers, the
19023 This new type has the format:
19027 \begin_inset Tabular
19028 <lyxtabular version="3" rows="2" columns="7">
19030 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19031 <column alignment="center" valignment="top" width="0">
19032 <column alignment="center" valignment="top" leftline="true" width="0">
19033 <column alignment="center" valignment="top" leftline="true" width="0">
19034 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19035 <column alignment="center" valignment="top" width="0">
19036 <column alignment="left" valignment="top" rightline="true" width="0">
19037 <row topline="true" bottomline="true">
19038 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19046 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19054 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19062 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19070 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19078 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19083 rest of the pointer
19086 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19095 <row topline="true" bottomline="true">
19096 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19104 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19112 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19120 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19128 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19136 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19148 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19153 upper byte high nubble is 0x2n, the rest are zeroes
19164 Currently implemented there are 3 types of streams defined:
19168 \begin_inset Tabular
19169 <lyxtabular version="3" rows="4" columns="4">
19171 <column alignment="center" valignment="top" leftline="true" width="0">
19172 <column alignment="center" valignment="top" leftline="true" width="0">
19173 <column alignment="center" valignment="top" leftline="true" width="0">
19174 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19175 <row topline="true" bottomline="true">
19176 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19184 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19192 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19200 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19209 <row topline="true">
19210 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19218 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19228 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19236 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19241 Writes/Reads characters via the USART peripheral
19245 <row topline="true">
19246 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19254 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19264 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19272 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19277 Writes/Reads characters via the MSSP peripheral
19281 <row topline="true" bottomline="true">
19282 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19290 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19300 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19308 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19313 Writes/Reads characters via used defined functions
19324 The stream identifiers are declared as macros in the stdio.h header.
19327 In the libc library there exist the functions that are used to write to
19328 each of the above streams.
19331 \labelwidthstring 00.00.0000
19343 _stream_usart_putchar writes a character at the USART stream
19345 \labelwidthstring 00.00.0000
19357 _stream_mssp_putchar writes a character at the MSSP stream
19359 \labelwidthstring 00.00.0000
19361 putchar dummy function.
19362 This writes a character to a user specified manner.
19365 In order to increase performance
19369 is declared in stdio.h as having its parameter in WREG (it has the wparam
19371 In stdio.h exists the macro PUTCHAR(arg) that defines the putchar function
19372 in a user-friendly way.
19377 is the name of the variable that holds the character to print.
19378 An example follows:
19381 #include <pic18fregs.h>
19393 PORTA = c; /* dump character c to PORTA */
19406 stdout = STREAM_USER; /* this is not necessery, since stdout points
19409 * by default to STREAM_USER */
19412 printf (¨This is a printf test
19420 \layout Subsubsection
19425 PIC16 contains an implementation of the printf-family of functions.
19426 There exist the following functions:
19429 extern unsigned int sprintf(char *buf, char *fmt, ...);
19432 extern unsigned int vsprintf(char *buf, char *fmt, va_list ap);
19437 extern unsigned int printf(char *fmt, ...);
19440 extern unsigned int vprintf(char *fmt, va_lista ap);
19445 extern unsigned int fprintf(FILE *fp, char *fmt, ...);
19448 extern unsigned int vfprintf(FILE *fp, char *fmt, va_list ap);
19451 For sprintf and vsprintf
19455 should normally be a data pointer where the resulting string will be placed.
19456 No range checking is done so the user should allocate the necessery buffer.
19457 For fprintf and vfprintf
19461 should be a stream pointer (i.e.
19462 stdout, STREAM_MSSP, etc...).
19463 \layout Subsubsection
19468 The PIC18F family of microcontrollers supports a number of interrupt sources.
19469 A list of these interrupts is shown in the following table:
19473 \begin_inset Tabular
19474 <lyxtabular version="3" rows="11" columns="4">
19476 <column alignment="left" valignment="top" leftline="true" width="0">
19477 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19478 <column alignment="left" valignment="top" leftline="true" width="0">
19479 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
19480 <row topline="true" bottomline="true">
19481 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19489 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19497 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19505 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19514 <row topline="true">
19515 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19523 <cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19528 PORTB change interrupt
19531 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19539 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19544 EEPROM/FLASH write complete interrupt
19548 <row topline="true">
19549 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19557 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19562 INT0 external interrupt
19565 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19573 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19578 Bus collision interrupt
19582 <row topline="true">
19583 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19591 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19596 INT1 external interrupt
19599 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19607 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19612 Low voltage detect interrupt
19616 <row topline="true">
19617 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19625 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19630 INT2 external interrupt
19633 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19641 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19646 Parallel slave port interrupt
19650 <row topline="true">
19651 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19659 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19664 CCP1 module interrupt
19667 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19675 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19680 AD convertion complete interrupt
19684 <row topline="true">
19685 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19693 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19698 CCP2 module interrupt
19701 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19709 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19714 USART receive interrupt
19718 <row topline="true">
19719 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19727 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19732 TMR0 overflow interrupt
19735 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19743 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19748 USART transmit interrupt
19752 <row topline="true">
19753 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19761 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19766 TMR1 overflow interrupt
19769 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19777 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19782 SSP receive/transmit interrupt
19786 <row topline="true">
19787 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19795 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19800 TMR2 matches PR2 interrupt
19803 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19810 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19818 <row topline="true" bottomline="true">
19819 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
19827 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19832 TMR3 overflow interrupt
19835 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19842 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
19857 The prototypes for these names are defined in the header file
19864 In order to simplify signal handling, a number of macros is provided:
19866 \labelwidthstring 00.00.0000
19868 DEF_INTHIGH(name) begin the definition of the interrupt dispatch table for
19869 high priority interrupts.
19874 is the function name to use.
19876 \labelwidthstring 00.00.0000
19878 DEF_INTLOW(name) begin the definition of the interrupt dispatch table fo
19879 low priority interrupt.
19884 is the function name to use.
19886 \labelwidthstring 00.00.0000
19888 DEF_HANDLER(sig,handler) define a handler for signal
19892 \labelwidthstring 00.00.0000
19894 END_DEF end the declaration of the dispatch table.
19897 Additionally there are two more macros to simplify the declaration of the
19900 \labelwidthstring 00.00.0000
19904 SIGHANDLER(handler)
19906 this declares the function prototype for the
19912 \labelwidthstring 00.00.0000
19914 SIGHANDLERNAKED(handler) same as SIGHANDLER() but declares a naked function.
19917 An example of using the macros above is shown below:
19920 #include <pic18fregs.h>
19923 #include <signal.h>
19927 DEF_INTHIGH(high_int)
19930 DEF_HANDLER(SIG_TMR0, _tmr0_handler)
19933 DEF_HANDLER(SIG_BCOL, _bcol_handler)
19940 SIGHANDLER(_tmr0_handler)
19946 /* action to be taken when timer 0 overflows */
19953 SIGHANDLERNAKED(_bcol_handler)
19962 /* action to be taken when bus collision occurs */
19978 Special care should be taken when using the above scheme:
19981 do not place a colon (;) at the end of the DEF_* and END_DEF macros.
19984 when declaring SIGHANDLERNAKED handler never forget to use
19988 for proper returning.
19994 Here you can find some general tips for compiling programs with SDCC/pic16.
19995 \layout Subsubsection
20000 The default stack size (that is 64 bytes) probably is enough for many programs.
20001 One must take care that when there are many levels of function nesting,
20002 or there is excessive usage of stack, its size should be extended.
20003 An example of such a case is the printf/sprintf family of functions.
20004 If you encounter problems like not being able to print integers, then you
20005 need to set the stack size around the maximum (256 for small stack model).
20006 The following diagram shows what happens when calling printf to print an
20010 printf () --> ltoa () --> ultoa () --> divschar ()
20013 It is should be understood that stack is easily consumed when calling complicate
20015 Using command line arguments like -
20025 -fommit-frame-pointer might reduce stack usage by not creating unnecessery
20027 Other ways to reduce stack usage may exist.
20030 Debugging with SDCDB
20031 \begin_inset LatexCommand \label{cha:Debugging-with-SDCDB}
20036 \begin_inset LatexCommand \index{sdcdb (debugger)}
20043 SDCC is distributed with a source level debugger
20044 \begin_inset LatexCommand \index{Debugger}
20049 The debugger uses a command line interface, the command repertoire of the
20050 debugger has been kept as close to gdb
20051 \begin_inset LatexCommand \index{gdb}
20055 (the GNU debugger) as possible.
20056 The configuration and build process is part of the standard compiler installati
20057 on, which also builds and installs the debugger in the target directory
20058 specified during configuration.
20059 The debugger allows you debug BOTH at the C source and at the ASM source
20061 Sdcdb is currently not available on Win32 platforms.
20064 Compiling for Debugging
20078 \begin_inset LatexCommand \index{-\/-debug}
20082 option must be specified for all files for which debug information is to
20084 The complier generates a .adb file for each of these files.
20085 The linker creates the .cdb
20086 \begin_inset LatexCommand \index{<file>.cdb}
20091 \begin_inset LatexCommand \index{<file>.adb}
20095 files and the address information.
20096 This .cdb is used by the debugger.
20099 How the Debugger Works
20112 -debug option is specified the compiler generates extra symbol information
20113 some of which are put into the assembler source and some are put into the
20115 Then the linker creates the .cdb file from the individual .adb files with
20116 the address information for the symbols.
20117 The debugger reads the symbolic information generated by the compiler &
20118 the address information generated by the linker.
20119 It uses the SIMULATOR (Daniel's S51) to execute the program, the program
20120 execution is controlled by the debugger.
20121 When a command is issued for the debugger, it translates it into appropriate
20122 commands for the simulator.
20125 Starting the Debugger
20128 The debugger can be started using the following command line.
20129 (Assume the file you are debugging has the file name foo).
20143 The debugger will look for the following files.
20146 foo.c - the source file.
20149 foo.cdb - the debugger symbol information file.
20152 foo.ihx - the Intel hex format
20153 \begin_inset LatexCommand \index{Intel hex format}
20160 Command Line Options
20173 -directory=<source file directory> this option can used to specify the directory
20175 The debugger will look into the directory list specified for source, cdb
20177 The items in the directory list must be separated by ':', e.g.
20178 if the source files can be in the directories /home/src1 and /home/src2,
20189 -directory option should be -
20199 -directory=/home/src1:/home/src2.
20200 Note there can be no spaces in the option.
20204 -cd <directory> - change to the <directory>.
20207 -fullname - used by GUI front ends.
20210 -cpu <cpu-type> - this argument is passed to the simulator please see the
20211 simulator docs for details.
20214 -X <Clock frequency > this options is passed to the simulator please see
20215 the simulator docs for details.
20218 -s <serial port file> passed to simulator see the simulator docs for details.
20221 -S <serial in,out> passed to simulator see the simulator docs for details.
20224 -k <port number> passed to simulator see the simulator docs for details.
20230 As mentioned earlier the command interface for the debugger has been deliberatel
20231 y kept as close the GNU debugger gdb, as possible.
20232 This will help the integration with existing graphical user interfaces
20233 (like ddd, xxgdb or xemacs) existing for the GNU debugger.
20234 If you use a graphical user interface for the debugger you can skip this
20236 \layout Subsubsection*
20238 break [line | file:line | function | file:function]
20241 Set breakpoint at specified line or function:
20250 sdcdb>break foo.c:100
20252 sdcdb>break funcfoo
20254 sdcdb>break foo.c:funcfoo
20255 \layout Subsubsection*
20257 clear [line | file:line | function | file:function ]
20260 Clear breakpoint at specified line or function:
20269 sdcdb>clear foo.c:100
20271 sdcdb>clear funcfoo
20273 sdcdb>clear foo.c:funcfoo
20274 \layout Subsubsection*
20279 Continue program being debugged, after breakpoint.
20280 \layout Subsubsection*
20285 Execute till the end of the current function.
20286 \layout Subsubsection*
20291 Delete breakpoint number 'n'.
20292 If used without any option clear ALL user defined break points.
20293 \layout Subsubsection*
20295 info [break | stack | frame | registers ]
20298 info break - list all breakpoints
20301 info stack - show the function call stack.
20304 info frame - show information about the current execution frame.
20307 info registers - show content of all registers.
20308 \layout Subsubsection*
20313 Step program until it reaches a different source line.
20314 Note: pressing <return> repeats the last command.
20315 \layout Subsubsection*
20320 Step program, proceeding through subroutine calls.
20321 \layout Subsubsection*
20326 Start debugged program.
20327 \layout Subsubsection*
20332 Print type information of the variable.
20333 \layout Subsubsection*
20338 print value of variable.
20339 \layout Subsubsection*
20344 load the given file name.
20345 Note this is an alternate method of loading file for debugging.
20346 \layout Subsubsection*
20351 print information about current frame.
20352 \layout Subsubsection*
20357 Toggle between C source & assembly source.
20358 \layout Subsubsection*
20360 ! simulator command
20363 Send the string following '!' to the simulator, the simulator response is
20365 Note the debugger does not interpret the command being sent to the simulator,
20366 so if a command like 'go' is sent the debugger can loose its execution
20367 context and may display incorrect values.
20368 \layout Subsubsection*
20375 My name is Bobby Brown"
20378 Interfacing with DDD
20381 The screenshot was converted from png to eps with:
20382 \begin_inset Quotes sld
20385 bmeps -c -e8f -p3 ddd_example.png >ddd_example.eps
20386 \begin_inset Quotes srd
20389 which produces a pretty compact eps file which is free from compression
20393 The screenshot was included in sdccman.lyx cvs version 1.120 but later removed
20394 as this broke the build system on Sourceforge (pdf-file was broken).
20400 \begin_inset LatexCommand \url{http://cvs.sourceforge.net/viewcvs.py/*checkout*/sdcc/sdcc/doc/figures/ddd_example.eps}
20406 shows a screenshot of a debugging session with DDD
20407 \begin_inset LatexCommand \index{DDD (debugger)}
20411 (Unix only) on a simulated 8032.
20412 The debugging session might not run as smoothly as the screenshot suggests.
20413 The debugger allows setting of breakpoints, displaying and changing variables,
20414 single stepping through C and assembler code.
20417 The source was compiled with
20440 -debug ddd_example.c
20453 and DDD was invoked with
20460 ddd -debugger 'sdcdb -cpu 8032 ddd_example'
20463 Interfacing with XEmacs
20464 \begin_inset LatexCommand \index{XEmacs}
20469 \begin_inset LatexCommand \index{Emacs}
20476 Two files (in emacs lisp) are provided for the interfacing with XEmacs,
20477 sdcdb.el and sdcdbsrc.el.
20478 These two files can be found in the $(prefix)/bin directory after the installat
20480 These files need to be loaded into XEmacs for the interface to work.
20481 This can be done at XEmacs startup time by inserting the following into
20482 your '.xemacs' file (which can be found in your HOME directory):
20488 (load-file sdcdbsrc.el)
20494 .xemacs is a lisp file so the () around the command is REQUIRED.
20495 The files can also be loaded dynamically while XEmacs is running, set the
20496 environment variable 'EMACSLOADPATH' to the installation bin directory
20497 (<installdir>/bin), then enter the following command ESC-x load-file sdcdbsrc.
20498 To start the interface enter the following command:
20512 You will prompted to enter the file name to be debugged.
20517 The command line options that are passed to the simulator directly are bound
20518 to default values in the file sdcdbsrc.el.
20519 The variables are listed below, these values maybe changed as required.
20522 sdcdbsrc-cpu-type '51
20525 sdcdbsrc-frequency '11059200
20528 sdcdbsrc-serial nil
20531 The following is a list of key mapping for the debugger interface.
20542 ;;key\SpecialChar ~
20556 binding\SpecialChar ~
20580 ;;---\SpecialChar ~
20594 -------\SpecialChar ~
20636 sdcdb-next-from-src\SpecialChar ~
20664 sdcdb-back-from-src\SpecialChar ~
20692 sdcdb-cont-from-src\SpecialChar ~
20702 SDCDB continue command
20720 sdcdb-step-from-src\SpecialChar ~
20748 sdcdb-whatis-c-sexp\SpecialChar ~
20758 SDCDB ptypecommand for data at
20825 sdcdbsrc-delete\SpecialChar ~
20839 SDCDB Delete all breakpoints if no arg
20888 given or delete arg (C-u arg x)
20906 sdcdbsrc-frame\SpecialChar ~
20921 SDCDB Display current frame if no arg,
20970 given or display frame arg
21037 sdcdbsrc-goto-sdcdb\SpecialChar ~
21047 Goto the SDCDB output buffer
21065 sdcdb-print-c-sexp\SpecialChar ~
21076 SDCDB print command for data at
21143 sdcdbsrc-goto-sdcdb\SpecialChar ~
21153 Goto the SDCDB output buffer
21171 sdcdbsrc-mode\SpecialChar ~
21187 Toggles Sdcdbsrc mode (turns it off)
21202 sdcdb-finish-from-src\SpecialChar ~
21210 SDCDB finish command
21225 sdcdb-break\SpecialChar ~
21243 Set break for line with point
21258 sdcdbsrc-mode\SpecialChar ~
21274 Toggle Sdcdbsrc mode
21289 sdcdbsrc-srcmode\SpecialChar ~
21312 Here are a few guidelines that will help the compiler generate more efficient
21313 code, some of the tips are specific to this compiler others are generally
21314 good programming practice.
21317 Use the smallest data type to represent your data-value.
21318 If it is known in advance that the value is going to be less than 256 then
21319 use an 'unsigned char' instead of a 'short' or 'int'.
21320 Please note, that ANSI C requires both signed and unsigned chars to be
21321 promoted to 'signed int' before doing any operation.
21323 \begin_inset LatexCommand \index{type promotion}
21327 can be omitted, if the result is the same.
21328 The effect of the promotion rules together with the sign-extension is often
21335 unsigned char uc = 0xfe;
21337 if (uc * uc < 0) /* this is true! */
21356 (int) uc * (int) uc = (int) 0xfe * (int) 0xfe = (int) 0xfc04 = -1024
21366 (unsigned char) -12 / (signed char) -3 = ...
21369 No, the result is not 4:
21374 (int) (unsigned char) -12 / (int) (signed char) -3 =
21376 (int) (unsigned char) 0xf4 / (int) (signed char) 0xfd =
21378 (int) 0x00f4 / (int) 0xfffd =
21380 (int) 0x00f4 / (int) 0xfffd =
21382 (int) 244 / (int) -3 =
21384 (int) -81 = (int) 0xffaf;
21387 Don't complain, that gcc gives you a different result.
21388 gcc uses 32 bit ints, while SDCC uses 16 bit ints.
21389 Therefore the results are different.
21392 \begin_inset Quotes sld
21396 \begin_inset Quotes srd
21402 If well-defined overflow characteristics are important and negative values
21403 are not, or if you want to steer clear of sign-extension problems when
21404 manipulating bits or bytes, use one of the corresponding unsigned types.
21405 (Beware when mixing signed and unsigned values in expressions, though.)
21407 Although character types (especially unsigned char) can be used as "tiny"
21408 integers, doing so is sometimes more trouble than it's worth, due to unpredicta
21409 ble sign extension and increased code size.
21413 Use unsigned when it is known in advance that the value is not going to
21415 This helps especially if you are doing division or multiplication, bit-shifting
21416 or are using an array index.
21419 NEVER jump into a LOOP.
21422 Declare the variables to be local
21423 \begin_inset LatexCommand \index{local variables}
21427 whenever possible, especially loop control variables (induction).
21430 Since the compiler does not always do implicit integral promotion, the programme
21431 r should do an explicit cast when integral promotion is required.
21434 Reducing the size of division, multiplication & modulus operations can reduce
21435 code size substantially.
21436 Take the following code for example.
21442 foobar(unsigned int p1, unsigned char ch)
21450 unsigned char ch1 = p1 % ch ;
21461 For the modulus operation the variable ch will be promoted to unsigned int
21462 first then the modulus operation will be performed (this will lead to a
21463 call to support routine _moduint()), and the result will be casted to a
21465 If the code is changed to
21470 foobar(unsigned int p1, unsigned char ch)
21478 unsigned char ch1 = (unsigned char)p1 % ch ;
21489 It would substantially reduce the code generated (future versions of the
21490 compiler will be smart enough to detect such optimization opportunities).
21494 Have a look at the assembly listing to get a
21495 \begin_inset Quotes sld
21499 \begin_inset Quotes srd
21502 for the code generation.
21506 \begin_inset LatexCommand \index{Tools}
21510 included in the distribution
21514 \begin_inset Tabular
21515 <lyxtabular version="3" rows="12" columns="3">
21517 <column alignment="center" valignment="top" leftline="true" width="0pt">
21518 <column alignment="center" valignment="top" leftline="true" width="0pt">
21519 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
21520 <row topline="true" bottomline="true">
21521 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21529 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21537 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21546 <row topline="true">
21547 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21555 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21560 Simulator for various architectures
21563 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21572 <row topline="true">
21573 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21581 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21586 header file conversion
21589 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21594 sdcc/support/scripts
21598 <row topline="true">
21599 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21607 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21612 header file conversion
21615 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21620 sdcc/support/scripts
21624 <row topline="true">
21625 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21633 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21641 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21659 <row topline="true">
21660 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21668 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21676 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21694 <row topline="true">
21695 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21703 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21711 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21729 <row topline="true">
21730 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21738 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21746 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21764 <row topline="true">
21765 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21773 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21781 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21799 <row topline="true">
21800 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21808 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21816 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21834 <row topline="true">
21835 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21843 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21851 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21869 <row topline="true" bottomline="true">
21870 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21878 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21886 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21914 \begin_inset LatexCommand \index{Documentation}
21918 included in the distribution
21922 \begin_inset Tabular
21923 <lyxtabular version="3" rows="10" columns="2">
21925 <column alignment="left" valignment="top" leftline="true" width="0">
21926 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
21927 <row topline="true" bottomline="true">
21928 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21936 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21941 Where to get / filename
21945 <row topline="true">
21946 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21951 SDCC Compiler User Guide
21954 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21959 You're reading it right now
21963 <row topline="true">
21964 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21972 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
21981 <row topline="true">
21982 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
21988 \begin_inset LatexCommand \index{asXXXX (as-gbz80, as-hc08, asx8051, as-z80)}
21993 \begin_inset LatexCommand \index{Assembler documentation}
21997 Assemblers and ASLINK
21998 \begin_inset LatexCommand \index{aslink}
22003 \begin_inset LatexCommand \index{Linker documentation}
22010 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22015 sdcc/as/doc/asxhtm.html
22019 <row topline="true">
22020 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22025 SDCC regression test
22026 \begin_inset LatexCommand \index{Regression test}
22033 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22038 sdcc/doc/test_suite_spec.pdf
22042 <row topline="true">
22043 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22051 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22060 <row topline="true">
22061 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22066 Notes on debugging with sdcdb
22067 \begin_inset LatexCommand \index{sdcdb (debugger)}
22074 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22079 sdcc/debugger/README
22083 <row topline="true">
22084 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22089 Software simulator for microcontrollers
22092 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22119 <row topline="true">
22120 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22125 Temporary notes on the pic16
22126 \begin_inset LatexCommand \index{PIC16}
22133 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22138 sdcc/src/pic16/NOTES
22142 <row topline="true" bottomline="true">
22143 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22148 SDCC internal documentation (debugging file format)
22151 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22187 Related open source tools
22188 \begin_inset LatexCommand \index{Related tools}
22196 \begin_inset Tabular
22197 <lyxtabular version="3" rows="11" columns="3">
22199 <column alignment="center" valignment="top" leftline="true" width="0pt">
22200 <column alignment="block" valignment="top" leftline="true" width="30line%">
22201 <column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
22202 <row topline="true" bottomline="true">
22203 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22211 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22219 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22228 <row topline="true">
22229 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22235 \begin_inset LatexCommand \index{gpsim (pic simulator)}
22242 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22250 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22256 \begin_inset LatexCommand \url{http://www.dattalo.com/gnupic/gpsim.html}
22264 <row topline="true">
22265 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22271 \begin_inset LatexCommand \index{gputils (pic tools)}
22278 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22286 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22292 \begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
22300 <row topline="true">
22301 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22309 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22317 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22323 \begin_inset LatexCommand \url{http://freshmeat.net/projects/flp5/}
22331 <row topline="true">
22332 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22338 \begin_inset LatexCommand \index{indent (source formatting tool)}
22345 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22350 Formats C source - Master of the white spaces
22353 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22359 \begin_inset LatexCommand \url{http://directory.fsf.org/GNU/indent.html}
22367 <row topline="true">
22368 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22374 \begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
22381 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22386 Object file conversion, checksumming, ...
22389 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22395 \begin_inset LatexCommand \url{http://sourceforge.net/projects/srecord}
22403 <row topline="true">
22404 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22410 \begin_inset LatexCommand \index{objdump (tool)}
22417 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22422 Object file conversion, ...
22425 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22430 Part of binutils (should be there anyway)
22434 <row topline="true">
22435 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22441 \begin_inset LatexCommand \index{doxygen (source documentation tool)}
22448 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22453 Source code documentation system
22456 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22462 \begin_inset LatexCommand \url{http://www.doxygen.org}
22470 <row topline="true">
22471 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22479 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22484 IDE (has anyone tried integrating SDCC & sdcdb? Unix only)
22487 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22493 \begin_inset LatexCommand \url{http://www.kdevelop.org}
22501 <row topline="true">
22502 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22508 \begin_inset LatexCommand \index{splint (syntax checking tool)}
22515 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22520 Statically checks c sources (see
22521 \begin_inset LatexCommand \ref{lyx:more-pedantic-SPLINT}
22528 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22534 \begin_inset LatexCommand \url{http://www.splint.org}
22542 <row topline="true" bottomline="true">
22543 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22549 \begin_inset LatexCommand \index{ddd (debugger)}
22556 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22561 Debugger, serves nicely as GUI to sdcdb
22562 \begin_inset LatexCommand \index{sdcdb (debugger)}
22569 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22575 \begin_inset LatexCommand \url{http://www.gnu.org/software/ddd/}
22592 Related documentation / recommended reading
22596 \begin_inset Tabular
22597 <lyxtabular version="3" rows="6" columns="3">
22599 <column alignment="center" valignment="top" leftline="true" width="0pt">
22600 <column alignment="block" valignment="top" leftline="true" width="30line%">
22601 <column alignment="center" valignment="top" leftline="true" rightline="true" width="0pt">
22602 <row topline="true" bottomline="true">
22603 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22611 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22619 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22628 <row topline="true">
22629 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22646 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22652 \begin_inset LatexCommand \index{C Reference card}
22659 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22665 \begin_inset LatexCommand \url{http://refcards.com/refcards/c/index.html}
22673 <row topline="true">
22674 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22682 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22690 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22696 \begin_inset LatexCommand \url{http://www.eskimo.com/~scs/C-faq/top.html}
22704 <row topline="true">
22705 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22712 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22717 Latest datasheet of the target CPU
22720 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22729 <row topline="true">
22730 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22737 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22742 Revision history of datasheet
22745 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22754 <row topline="true" bottomline="true">
22755 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22765 <cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
22770 Advanced Compiler Design and Implementation
22773 <cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
22778 bookstore (very dedicated, probably read other books first)
22794 Some questions answered, some pointers given - it might be time to in turn
22802 can you solve your project with the selected microcontroller? Would you
22803 find out early or rather late that your target is too small/slow/whatever?
22804 Can you switch to a slightly better device if it doesn't fit?
22807 should you solve the problem with an 8 bit CPU? Or would a 16/32 bit CPU
22808 and/or another programming language be more adequate? Would an operating
22809 system on the target device help?
22812 if you solved the problem, will the marketing department be happy?
22815 if the marketing department is happy, will customers be happy?
22818 if you're the project manager, marketing department and maybe even the customer
22819 in one person, have you tried to see the project from the outside?
22822 is the project done if you think it is done? Or is just that other interface/pro
22823 tocol/feature/configuration/option missing? How about website, manual(s),
22824 internationali(z|s)ation, packaging, labels, 2nd source for components,
22825 electromagnetic compatability/interference, documentation for production,
22826 production test software, update mechanism, patent issues?
22829 is your project adequately positioned in that magic triangle: fame, fortune,
22833 Maybe not all answers to these questions are known and some answers may
22838 , nevertheless knowing these questions may help you to avoid burnout
22844 burnout is bad for electronic devices, programmers and motorcycle tyres
22848 Chances are you didn't want to hear some of them...
22852 \begin_inset LatexCommand \index{Support}
22859 SDCC has grown to be a large project.
22860 The compiler alone (without the preprocessor, assembler and linker) is
22861 well over 100,000 lines of code (blank stripped).
22862 The open source nature of this project is a key to its continued growth
22864 You gain the benefit and support of many active software developers and
22866 Is SDCC perfect? No, that's why we need your help.
22867 The developers take pride in fixing reported bugs.
22868 You can help by reporting the bugs and helping other SDCC users.
22869 There are lots of ways to contribute, and we encourage you to take part
22870 in making SDCC a great software package.
22874 The SDCC project is hosted on the SDCC sourceforge site at
22875 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/projects/sdcc}
22880 You'll find the complete set of mailing lists
22881 \begin_inset LatexCommand \index{Mailing list(s)}
22885 , forums, bug reporting system, patch submission
22886 \begin_inset LatexCommand \index{Patch submission}
22891 \begin_inset LatexCommand \index{download}
22895 area and cvs code repository
22896 \begin_inset LatexCommand \index{cvs code repository}
22904 \begin_inset LatexCommand \index{Bug reporting}
22909 \begin_inset LatexCommand \index{Reporting bugs}
22916 The recommended way of reporting bugs is using the infrastructure of the
22918 You can follow the status of bug reports there and have an overview about
22922 Bug reports are automatically forwarded to the developer mailing list and
22923 will be fixed ASAP.
22924 When reporting a bug, it is very useful to include a small test program
22925 (the smaller the better) which reproduces the problem.
22926 If you can isolate the problem by looking at the generated assembly code,
22927 this can be very helpful.
22928 Compiling your program with the -
22939 \begin_inset LatexCommand \index{-\/-dumpall}
22943 option can sometimes be useful in locating optimization problems.
22944 When reporting a bug please maker sure you:
22947 Attach the code you are compiling with SDCC.
22951 Specify the exact command you use to run SDCC, or attach your Makefile.
22955 Specify the SDCC version (type "
22961 "), your platform, and operating system.
22965 Provide an exact copy of any error message or incorrect output.
22969 Put something meaningful in the subject of your message.
22972 Please attempt to include these 5 important parts, as applicable, in all
22973 requests for support or when reporting any problems or bugs with SDCC.
22974 Though this will make your message lengthy, it will greatly improve your
22975 chance that SDCC users and developers will be able to help you.
22976 Some SDCC developers are frustrated by bug reports without code provided
22977 that they can use to reproduce and ultimately fix the problem, so please
22978 be sure to provide sample code if you are reporting a bug!
22981 Please have a short check that you are using a recent version of SDCC and
22982 the bug is not yet known.
22983 This is the link for reporting bugs:
22984 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=100599}
22991 Requesting Features
22992 \begin_inset LatexCommand \label{sub:Requesting-Features}
22997 \begin_inset LatexCommand \index{Feature request}
23002 \begin_inset LatexCommand \index{Requesting features}
23009 Like bug reports feature requests are forwarded to the developer mailing
23011 This is the link for requesting features:
23012 \begin_inset LatexCommand \htmlurl{http://sourceforge.net/tracker/?group_id=599&atid=350599}
23022 Like bug reports contributed patches are forwarded to the developer mailing
23024 This is the link for submitting patches
23025 \begin_inset LatexCommand \index{Patch submission}
23030 \begin_inset LatexCommand \url{http://sourceforge.net/tracker/?group_id=599&atid=300599}
23037 You need to specify some parameters to the
23041 command for the patches to be useful.
23042 If you modified more than one file a patch created f.e.
23047 \begin_inset Quotes sld
23050 diff -Naur unmodified_directory modified_directory >my_changes.patch
23051 \begin_inset Quotes srd
23057 will be fine, otherwise
23061 \begin_inset Quotes sld
23064 diff -u sourcefile.c.orig sourcefile.c >my_changes.patch
23065 \begin_inset Quotes srd
23078 These links should take you directly to the
23079 \begin_inset LatexCommand \url[Mailing lists]{http://sourceforge.net/mail/?group_id=599}
23089 Traffic on sdcc-devel and sdcc-user is about 100 mails/month each not counting
23090 automated messages (mid 2003)
23094 \begin_inset LatexCommand \url[Forums]{http://sourceforge.net/forum/?group_id=599}
23099 \begin_inset LatexCommand \index{Mailing list(s)}
23103 and forums are archived and searchable so if you are lucky someone already
23104 had a similar problem.
23105 While mails to the lists themselves are delivered promptly their web front
23106 end on sourceforge sometimes shows a severe time lag (up to several weeks),
23107 if you're seriously using SDCC please consider subscribing to the lists.
23113 You can follow the status of the cvs version
23114 \begin_inset LatexCommand \index{version}
23118 of SDCC by watching the Changelog
23119 \begin_inset LatexCommand \index{Changelog}
23123 in the cvs-repository
23128 \begin_inset LatexCommand \htmlurl{http://cvs.sf.net/cgi-bin/viewcvs.cgi/*checkout*/sdcc/sdcc/ChangeLog?rev=HEAD&content-type=text/plain}
23136 \begin_inset LatexCommand \index{Release policy}
23143 Historically there often were long delays between official releases and
23144 the sourceforge download area tends to get not updated at all.
23145 Excuses in the past might have referred to problems with live range analysis,
23146 but as this was fixed a while ago, the current problem is that another
23147 excuse has to be found.
23148 Kidding aside, we have to get better there! On the other hand there are
23149 daily snapshots available at
23150 \begin_inset LatexCommand \htmlurl[snap]{http://sdcc.sourceforge.net/snap.php}
23154 , and you can always build the very last version (hopefully with many bugs
23155 fixed, and features added) from the source code available at
23156 \begin_inset LatexCommand \htmlurl[Source]{http://sdcc.sourceforge.net/snap.php#Source}
23164 \begin_inset LatexCommand \index{Examples}
23171 You'll find some small examples in the directory
23173 sdcc/device/examples/.
23176 More examples and libraries are available at
23178 The SDCC Open Knowledge Resource
23179 \begin_inset LatexCommand \url{http://sdccokr.dl9sec.de/}
23186 \begin_inset LatexCommand \url{http://www.pjrc.com/tech/8051/}
23193 I did insert a reference to Paul's web site here although it seems rather
23194 dedicated to a specific 8032 board (I think it's okay because it f.e.
23195 shows LCD/Harddisc interface and has a free 8051 monitor.
23196 Independent 8032 board vendors face hard competition of heavily subsidized
23197 development boards anyway).
23200 Maybe we should include some links to real world applications.
23201 Preferably pointer to pointers (one for each architecture) so this stays
23206 \begin_inset LatexCommand \index{Quality control}
23213 The compiler is passed through nightly compile and build checks.
23219 \begin_inset LatexCommand \index{Regression test}
23223 check that SDCC itself compiles flawlessly on several platforms and checks
23224 the quality of the code generated by SDCC by running the code through simulator
23226 There is a separate document
23229 \begin_inset LatexCommand \index{Test suite}
23238 You'll find the test code in the directory
23240 sdcc/support/regression
23243 You can run these tests manually by running
23247 in this directory (or f.e.
23252 \begin_inset Quotes sld
23256 \begin_inset Quotes srd
23262 if you don't want to run the complete tests).
23263 The test code might also be interesting if you want to look for examples
23264 \begin_inset LatexCommand \index{Examples}
23268 checking corner cases of SDCC or if you plan to submit patches
23269 \begin_inset LatexCommand \index{Patch submission}
23276 The pic port uses a different set of regression tests, you'll find them
23279 sdcc/src/regression
23284 SDCC Technical Data
23288 \begin_inset LatexCommand \index{Optimizations}
23295 SDCC performs a host of standard optimizations in addition to some MCU specific
23300 Sub-expression Elimination
23301 \begin_inset LatexCommand \index{Subexpression elimination}
23308 The compiler does local and
23334 will be translated to
23346 Some subexpressions are not as obvious as the above example, e.g.:
23356 In this case the address arithmetic a->b[i] will be computed only once;
23357 the equivalent code in C would be.
23369 The compiler will try to keep these temporary variables in registers.
23372 Dead-Code Elimination
23373 \begin_inset LatexCommand \index{Dead-code elimination}
23394 i = 1; \SpecialChar ~
23403 global = 1;\SpecialChar ~
23416 global = 3;\SpecialChar ~
23441 \begin_inset LatexCommand \index{Copy propagation}
23497 Note: the dead stores created by this copy propagation will be eliminated
23498 by dead-code elimination.
23502 \begin_inset LatexCommand \index{Loop optimization}
23507 \begin_inset LatexCommand \label{sub:Loop-Optimizations}
23514 Two types of loop optimizations are done by SDCC
23522 of loop induction variables.
23523 In addition to the strength reduction the optimizer marks the induction
23524 variables and the register allocator tries to keep the induction variables
23525 in registers for the duration of the loop.
23526 Because of this preference of the register allocator
23527 \begin_inset LatexCommand \index{Register allocation}
23531 , loop induction optimization causes an increase in register pressure, which
23532 may cause unwanted spilling of other temporary variables into the stack
23533 \begin_inset LatexCommand \index{stack}
23538 The compiler will generate a warning message when it is forced to allocate
23539 extra space either on the stack or data space.
23540 If this extra space allocation is undesirable then induction optimization
23541 can be eliminated either for the entire source file (with -
23551 -noinduction option) or for a given function only using #pragma\SpecialChar ~
23553 \begin_inset LatexCommand \index{\#pragma noinduction}
23566 for (i = 0 ; i < 100 ; i ++)
23582 for (i = 0; i < 100; i++)
23591 As mentioned previously some loop invariants are not as apparent, all static
23592 address computations are also moved out of the loop.
23597 \begin_inset LatexCommand \index{Strength reduction}
23601 , this optimization substitutes an expression by a cheaper expression:
23606 for (i=0;i < 100; i++)
23624 for (i=0;i< 100;i++) {
23630 ar[itemp1] = itemp2;
23647 The more expensive multiplication
23648 \begin_inset LatexCommand \index{Multiplication}
23652 is changed to a less expensive addition.
23656 \begin_inset LatexCommand \index{Loop reversing}
23663 This optimization is done to reduce the overhead of checking loop boundaries
23664 for every iteration.
23665 Some simple loops can be reversed and implemented using a
23666 \begin_inset Quotes eld
23669 decrement and jump if not zero
23670 \begin_inset Quotes erd
23674 SDCC checks for the following criterion to determine if a loop is reversible
23675 (note: more sophisticated compilers use data-dependency analysis to make
23676 this determination, SDCC uses a more simple minded analysis).
23679 The 'for' loop is of the form
23685 for(<symbol> = <expression>; <sym> [< | <=] <expression>; [<sym>++ | <sym>
23695 The <for body> does not contain
23696 \begin_inset Quotes eld
23700 \begin_inset Quotes erd
23704 \begin_inset Quotes erd
23710 All goto's are contained within the loop.
23713 No function calls within the loop.
23716 The loop control variable <sym> is not assigned any value within the loop
23719 The loop control variable does NOT participate in any arithmetic operation
23723 There are NO switch statements in the loop.
23726 Algebraic Simplifications
23729 SDCC does numerous algebraic simplifications, the following is a small sub-set
23730 of these optimizations.
23735 i = j + 0;\SpecialChar ~
23739 /* changed to: */\SpecialChar ~
23745 i /= 2;\SpecialChar ~
23752 /* changed to: */\SpecialChar ~
23758 i = j - j;\SpecialChar ~
23762 /* changed to: */\SpecialChar ~
23768 i = j / 1;\SpecialChar ~
23772 /* changed to: */\SpecialChar ~
23779 Note the subexpressions
23780 \begin_inset LatexCommand \index{Subexpression}
23784 given above are generally introduced by macro expansions or as a result
23785 of copy/constant propagation.
23788 'switch' Statements
23789 \begin_inset LatexCommand \label{sub:'switch'-Statements}
23794 \begin_inset LatexCommand \index{switch statement}
23801 SDCC can optimize switch statements to jump tables
23802 \begin_inset LatexCommand \index{jump tables}
23807 It makes the decision based on an estimate of the generated code size.
23808 SDCC is quite liberal in the requirements for jump table generation:
23811 The labels need not be in order, and the starting number need not be one
23812 or zero, the case labels are in numerical sequence or not too many case
23813 labels are missing.
23819 switch(i) {\SpecialChar ~
23850 case 4: ...\SpecialChar ~
23882 case 5: ...\SpecialChar ~
23914 case 3: ...\SpecialChar ~
23945 case 6: ...\SpecialChar ~
23977 case 7: ...\SpecialChar ~
24009 case 8: ...\SpecialChar ~
24041 case 9: ...\SpecialChar ~
24073 case 10: ...\SpecialChar ~
24104 case 11: ...\SpecialChar ~
24171 Both the above switch statements will be implemented using a jump-table.
24172 The example to the right side is slightly more efficient as the check for
24173 the lower boundary of the jump-table is not needed.
24177 The number of case labels is not larger than supported by the target architectur
24181 If the case labels are not in numerical sequence ('gaps' between cases)
24182 SDCC checks whether a jump table with additionally inserted dummy cases
24183 is still attractive.
24187 If the starting number is not zero and a check for the lower boundary of
24188 the jump-table can thus be eliminated SDCC might insert dummy cases 0,
24193 Switch statements which have large gaps in the numeric sequence or those
24194 that have too many case labels can be split into more than one switch statement
24195 for efficient code generation, e.g.:
24275 If the above switch statement is broken down into two switch statements
24365 then both the switch statements will be implemented using jump-tables whereas
24366 the unmodified switch statement will not be.
24369 There might be reasons which SDCC cannot know about to either favour or
24370 not favour jump tables.
24371 If the target system has to be as quick for the last switch case as for
24372 the first (pro jump table), or if the switch argument is known to be zero
24373 in the majority of the cases (contra jump table).
24376 The pragma nojtbound
24377 \begin_inset LatexCommand \index{\#pragma nojtbound}
24381 can be used to turn off checking the
24394 It has no effect if a default label is supplied.
24395 Use of this pragma is dangerous: if the switch
24396 \begin_inset LatexCommand \index{switch statement}
24400 argument is not matched by a case statement the processor will happily
24404 Bit-shifting Operations
24405 \begin_inset LatexCommand \index{Bit shifting}
24412 Bit shifting is one of the most frequently used operation in embedded programmin
24414 SDCC tries to implement bit-shift operations in the most efficient way
24430 generates the following code:
24447 In general SDCC will never setup a loop if the shift count is known.
24490 \begin_inset LatexCommand \index{Bit rotation}
24497 A special case of the bit-shift operation is bit rotation
24498 \begin_inset LatexCommand \index{rotating bits}
24502 , SDCC recognizes the following expression to be a left bit-rotation:
24512 char i;\SpecialChar ~
24523 /* unsigned is needed for rotation */
24528 i = ((i << 1) | (i >> 7));
24537 will generate the following code:
24556 SDCC uses pattern matching on the parse tree to determine this operation.Variatio
24557 ns of this case will also be recognized as bit-rotation, i.e.:
24562 i = ((i >> 7) | (i << 1)); /* left-bit rotation */
24565 Nibble and Byte Swapping
24568 Other special cases of the bit-shift operations are nibble or byte swapping
24569 \begin_inset LatexCommand \index{swapping nibbles/bytes}
24573 , SDCC recognizes the following expressions:
24596 i = ((i << 4) | (i >> 4));
24602 j = ((j << 8) | (j >> 8));
24605 and generates a swap instruction for the nibble swapping
24606 \begin_inset LatexCommand \index{Nibble swapping}
24610 or move instructions for the byte swapping
24611 \begin_inset LatexCommand \index{Byte swapping}
24617 \begin_inset Quotes sld
24621 \begin_inset Quotes srd
24624 example can be used to convert from little to big-endian or vice versa.
24625 If you want to change the endianness of a
24629 integer you have to cast to
24636 Note that SDCC stores numbers in little-endian
24642 Usually 8-bit processors don't care much about endianness.
24643 This is not the case for the standard 8051 which only has an instruction
24649 \begin_inset LatexCommand \index{DPTR}
24657 so little-endian is the more efficient byte order.
24661 \begin_inset LatexCommand \index{little-endian}
24666 \begin_inset LatexCommand \index{Endianness}
24671 lowest order first).
24675 \begin_inset LatexCommand \index{Highest Order Bit}
24680 \begin_inset LatexCommand \index{Any Order Bit}
24687 It is frequently required to obtain the highest order bit of an integral
24688 type (long, int, short or char types).
24689 Also obtaining any other order bit is not uncommon.
24690 SDCC recognizes the following expressions to yield the highest order bit
24691 and generates optimized code for it, e.g.:
24704 unsigned char hob1, aob1;
24708 bit hob2, hob3, aob2, aob3;
24717 hob1 = (gint >> 15) & 1;
24721 hob2 = (gint >> 15) & 1;
24725 hob3 = gint & 0x8000;
24729 aob1 = (gint >> 9) & 1;
24733 aob2 = (gint >> 8) & 1;
24737 aob3 = gint & 0x0800;
24747 will generate the following code:
24780 000A E5*01\SpecialChar ~
24807 000C 23\SpecialChar ~
24838 000D 54 01\SpecialChar ~
24865 000F F5*02\SpecialChar ~
24920 0011 E5*01\SpecialChar ~
24947 0013 33\SpecialChar ~
24977 0014 92*00\SpecialChar ~
25032 0016 E5*01\SpecialChar ~
25059 0018 33\SpecialChar ~
25089 0019 92*01\SpecialChar ~
25144 001B E5*01\SpecialChar ~
25171 001D 03\SpecialChar ~
25202 001E 54 01\SpecialChar ~
25229 0020 F5*03\SpecialChar ~
25284 0022 E5*01\SpecialChar ~
25311 0024 13\SpecialChar ~
25341 0025 92*02\SpecialChar ~
25396 0027 E5*01\SpecialChar ~
25423 0029 A2 E3\SpecialChar ~
25450 002B 92*03\SpecialChar ~
25478 Other variations of these cases however will
25483 They are standard C expressions, so I heartily recommend these be the only
25484 way to get the highest order bit, (it is portable).
25485 Of course it will be recognized even if it is embedded in other expressions,
25491 xyz = gint + ((gint >> 15) & 1);
25494 will still be recognized.
25498 \begin_inset LatexCommand \index{Higher Order Byte}
25502 / Higher Order Word
25503 \begin_inset LatexCommand \index{Higher Order Word}
25510 It is also frequently required to obtain a higher order byte or word of
25511 a larger integral type (long, int or short types).
25512 SDCC recognizes the following expressions to yield the higher order byte
25513 or word and generates optimized code for it, e.g.:
25520 unsigned long int glong;
25528 unsigned char hob1, hob2;
25532 unsigned int how1, how2;
25541 hob1 = (gint >> 8) & 0xFF;
25545 hob2 = glong >> 24;
25549 how1 = (glong >> 16) & 0xFFFF;
25563 will generate the following code:
25596 0037 85*01*06\SpecialChar ~
25618 _foo_hob1_1_1,(_gint + 1)
25648 003A 85*05*07\SpecialChar ~
25670 _foo_hob2_1_1,(_glong + 3)
25700 003D 85*04*08\SpecialChar ~
25722 _foo_how1_1_1,(_glong + 2)
25724 0040 85*05*09\SpecialChar ~
25746 (_foo_how1_1_1 + 1),(_glong + 3)
25748 0043 85*03*0A\SpecialChar ~
25770 _foo_how2_1_1,(_glong + 1)
25772 0046 85*04*0B\SpecialChar ~
25794 (_foo_how2_1_1 + 1),(_glong + 2)
25797 Again, variations of these cases may
25802 They are standard C expressions, so I heartily recommend these be the only
25803 way to get the higher order byte/word, (it is portable).
25804 Of course it will be recognized even if it is embedded in other expressions,
25810 xyz = gint + ((gint >> 8) & 0xFF);
25813 will still be recognized.
25817 \begin_inset LatexCommand \label{sub:Peephole-Optimizer}
25822 \begin_inset LatexCommand \index{Peephole optimizer}
25829 The compiler uses a rule based, pattern matching and re-writing mechanism
25830 for peep-hole optimization.
25835 a peep-hole optimizer by Christopher W.
25836 Fraser (cwfraser\SpecialChar ~
25839 A default set of rules are compiled into the compiler, additional rules
25840 may be added with the
25853 \begin_inset LatexCommand \index{-\/-peep-file}
25860 The rule language is best illustrated with examples.
25884 The above rule will change the following assembly
25885 \begin_inset LatexCommand \index{Assembler routines}
25907 Note: All occurrences of a
25911 (pattern variable) must denote the same string.
25912 With the above rule, the assembly sequence:
25922 will remain unmodified.
25926 Other special case optimizations may be added by the user (via
25942 some variants of the 8051 MCU
25943 \begin_inset LatexCommand \index{MCS51 variants}
25956 The following two rules will change all
25975 replace { lcall %1 } by { acall %1 }
25977 replace { ljmp %1 } by { ajmp %1 }
25982 inline-assembler code
25984 is also passed through the peep hole optimizer, thus the peephole optimizer
25985 can also be used as an assembly level macro expander.
25986 The rules themselves are MCU dependent whereas the rule language infra-structur
25987 e is MCU independent.
25988 Peephole optimization rules for other MCU can be easily programmed using
25993 The syntax for a rule is as follows:
25998 rule := replace [ restart ] '{' <assembly sequence> '
26036 <assembly sequence> '
26054 '}' [if <functionName> ] '
26059 <assembly sequence> := assembly instruction (each instruction including
26060 labels must be on a separate line).
26064 The optimizer will apply to the rules one by one from the top in the sequence
26065 of their appearance, it will terminate when all rules are exhausted.
26066 If the 'restart' option is specified, then the optimizer will start matching
26067 the rules again from the top, this option for a rule is expensive (performance)
26068 , it is intended to be used in situations where a transformation will trigger
26069 the same rule again.
26070 An example of this (not a good one, it has side effects) is the following
26093 Note that the replace pattern cannot be a blank, but can be a comment line.
26094 Without the 'restart' option only the innermost 'pop' 'push' pair would
26095 be eliminated, i.e.:
26125 the restart option the rule will be applied again to the resulting code
26126 and then all the pop-push pairs will be eliminated to yield:
26136 A conditional function can be attached to a rule.
26137 Attaching rules are somewhat more involved, let me illustrate this with
26164 The optimizer does a look-up of a function name table defined in function
26169 in the source file SDCCpeeph.c, with the name
26174 If it finds a corresponding entry the function is called.
26175 Note there can be no parameters specified for these functions, in this
26180 is crucial, since the function
26184 expects to find the label in that particular variable (the hash table containin
26185 g the variable bindings is passed as a parameter).
26186 If you want to code more such functions, take a close look at the function
26187 labelInRange and the calling mechanism in source file SDCCpeeph.c.
26188 Currently implemented are
26190 labelInRange, labelRefCount, labelIsReturnOnly, operandsNotSame, xramMovcOption,
26191 24bitMode, portIsDS390, 24bitModeAndPortDS390
26200 I know this whole thing is a little kludgey, but maybe some day we will
26201 have some better means.
26202 If you are looking at this file, you will see the default rules that are
26203 compiled into the compiler, you can add your own rules in the default set
26204 there if you get tired of specifying the -
26218 \begin_inset LatexCommand \index{ANSI-compliance}
26223 \begin_inset LatexCommand \label{sub:ANSI-Compliance}
26230 Deviations from the compliance:
26233 functions are not reentrant
26234 \begin_inset LatexCommand \index{reentrant}
26238 unless explicitly declared as such or the
26251 \begin_inset LatexCommand \index{-\/-stack-auto}
26257 command line option is specified.
26260 structures and unions cannot be assigned values directly, cannot be passed
26261 as function parameters or assigned to each other and cannot be a return
26262 value from a function, e.g.:
26288 s1 = s2 ; /* is invalid in SDCC although allowed in ANSI */
26299 struct s foo1 (struct s parms) /* invalid in SDCC although allowed in ANSI
26321 return rets;/* is invalid in SDCC although allowed in ANSI */
26327 initialization of structure arrays must be fully braced.
26333 struct s { char x } a[] = {1, 2}; /* invalid in SDCC */
26335 struct s { char x } a[] = {{1}, {2}}; /* OK */
26340 \begin_inset LatexCommand \index{long long (not supported)}
26345 \begin_inset LatexCommand \index{int (64 bit) (not supported)}
26353 \begin_inset LatexCommand \index{double (not supported)}
26357 ' precision floating point
26358 \begin_inset LatexCommand \index{Floating point support}
26365 No support for setjmp
26366 \begin_inset LatexCommand \index{setjmp (not supported)}
26371 \begin_inset LatexCommand \index{longjmp (not supported)}
26379 \begin_inset LatexCommand \index{K\&R style}
26383 function declarations are NOT allowed.
26389 foo(i,j) /* this old style of function declarations */
26391 int i,j; /* are valid in ANSI but not valid in SDCC */
26406 Certain words that are valid identifiers in the standard may be reserved
26407 words in SDCC unless the
26420 \begin_inset LatexCommand \index{-\/-std-c89}
26435 \begin_inset LatexCommand \index{-\/-std-c99}
26441 command line options are used.
26442 These may include (depending on the selected processor): 'at', 'banked',
26443 'bit', 'code', 'critical', 'data', 'eeprom', 'far', 'flash', 'idata', 'interrup
26444 t', 'near', 'nonbanked', 'pdata', 'reentrant', 'sbit', 'sfr', 'shadowregs',
26445 'sram', 'using', 'wparam', 'xdata', '_overlay', '_asm', '_endasm', and
26447 Compliant equivalents of these keywords are always available in a form
26448 that begin with two underscores
26449 \begin_inset LatexCommand \index{\_\_ (prefix for extended keywords)}
26454 '__data' instead of 'data'.
26457 Cyclomatic Complexity
26458 \begin_inset LatexCommand \index{Cyclomatic complexity}
26465 Cyclomatic complexity of a function is defined as the number of independent
26466 paths the program can take during execution of the function.
26467 This is an important number since it defines the number test cases you
26468 have to generate to validate the function.
26469 The accepted industry standard for complexity number is 10, if the cyclomatic
26470 complexity reported by SDCC exceeds 10 you should think about simplification
26471 of the function logic.
26472 Note that the complexity level is not related to the number of lines of
26473 code in a function.
26474 Large functions can have low complexity, and small functions can have large
26480 SDCC uses the following formula to compute the complexity:
26485 complexity = (number of edges in control flow graph) - (number of nodes
26486 in control flow graph) + 2;
26490 Having said that the industry standard is 10, you should be aware that in
26491 some cases it be may unavoidable to have a complexity level of less than
26493 For example if you have switch statement with more than 10 case labels,
26494 each case label adds one to the complexity level.
26495 The complexity level is by no means an absolute measure of the algorithmic
26496 complexity of the function, it does however provide a good starting point
26497 for which functions you might look at for further optimization.
26500 Retargetting for other Processors
26503 The issues for retargetting the compiler are far too numerous to be covered
26505 What follows is a brief description of each of the seven phases of the
26506 compiler and its MCU dependency.
26509 Parsing the source and building the annotated parse tree.
26510 This phase is largely MCU independent (except for the language extensions).
26511 Syntax & semantic checks are also done in this phase, along with some initial
26512 optimizations like back patching labels and the pattern matching optimizations
26513 like bit-rotation etc.
26516 The second phase involves generating an intermediate code which can be easy
26517 manipulated during the later phases.
26518 This phase is entirely MCU independent.
26519 The intermediate code generation assumes the target machine has unlimited
26520 number of registers, and designates them with the name iTemp.
26521 The compiler can be made to dump a human readable form of the code generated
26535 This phase does the bulk of the standard optimizations and is also MCU independe
26537 This phase can be broken down into several sub-phases:
26541 Break down intermediate code (iCode) into basic blocks.
26543 Do control flow & data flow analysis on the basic blocks.
26545 Do local common subexpression elimination, then global subexpression elimination
26547 Dead code elimination
26551 If loop optimizations caused any changes then do 'global subexpression eliminati
26552 on' and 'dead code elimination' again.
26555 This phase determines the live-ranges; by live range I mean those iTemp
26556 variables defined by the compiler that still survive after all the optimization
26558 Live range analysis
26559 \begin_inset LatexCommand \index{Live range analysis}
26563 is essential for register allocation, since these computation determines
26564 which of these iTemps will be assigned to registers, and for how long.
26567 Phase five is register allocation.
26568 There are two parts to this process.
26572 The first part I call 'register packing' (for lack of a better term).
26573 In this case several MCU specific expression folding is done to reduce
26578 The second part is more MCU independent and deals with allocating registers
26579 to the remaining live ranges.
26580 A lot of MCU specific code does creep into this phase because of the limited
26581 number of index registers available in the 8051.
26584 The Code generation phase is (unhappily), entirely MCU dependent and very
26585 little (if any at all) of this code can be reused for other MCU.
26586 However the scheme for allocating a homogenized assembler operand for each
26587 iCode operand may be reused.
26590 As mentioned in the optimization section the peep-hole optimizer is rule
26591 based system, which can reprogrammed for other MCUs.
26595 \begin_inset LatexCommand \index{Compiler internals}
26602 The anatomy of the compiler
26603 \begin_inset LatexCommand \label{sub:The-anatomy-of}
26612 This is an excerpt from an article published in Circuit Cellar Magazine
26618 It's a little outdated (the compiler is much more efficient now and user/develo
26619 per friendly), but pretty well exposes the guts of it all.
26625 The current version of SDCC can generate code for Intel 8051 and Z80 MCU.
26626 It is fairly easy to retarget for other 8-bit MCU.
26627 Here we take a look at some of the internals of the compiler.
26632 \begin_inset LatexCommand \index{Parsing}
26639 Parsing the input source file and creating an AST (Annotated Syntax Tree
26640 \begin_inset LatexCommand \index{Annotated syntax tree}
26645 This phase also involves propagating types (annotating each node of the
26646 parse tree with type information) and semantic analysis.
26647 There are some MCU specific parsing rules.
26648 For example the storage classes, the extended storage classes are MCU specific
26649 while there may be a xdata storage class for 8051 there is no such storage
26650 class for z80 or Atmel AVR.
26651 SDCC allows MCU specific storage class extensions, i.e.
26652 xdata will be treated as a storage class specifier when parsing 8051 C
26653 code but will be treated as a C identifier when parsing z80 or ATMEL AVR
26658 \begin_inset LatexCommand \index{iCode}
26665 Intermediate code generation.
26666 In this phase the AST is broken down into three-operand form (iCode).
26667 These three operand forms are represented as doubly linked lists.
26668 ICode is the term given to the intermediate form generated by the compiler.
26669 ICode example section shows some examples of iCode generated for some simple
26670 C source functions.
26674 \begin_inset LatexCommand \index{Optimizations}
26681 Bulk of the target independent optimizations is performed in this phase.
26682 The optimizations include constant propagation, common sub-expression eliminati
26683 on, loop invariant code movement, strength reduction of loop induction variables
26684 and dead-code elimination.
26687 Live range analysis
26688 \begin_inset LatexCommand \index{Live range analysis}
26695 During intermediate code generation phase, the compiler assumes the target
26696 machine has infinite number of registers and generates a lot of temporary
26698 The live range computation determines the lifetime of each of these compiler-ge
26699 nerated temporaries.
26700 A picture speaks a thousand words.
26701 ICode example sections show the live range annotations for each of the
26703 It is important to note here, each iCode is assigned a number in the order
26704 of its execution in the function.
26705 The live ranges are computed in terms of these numbers.
26706 The from number is the number of the iCode which first defines the operand
26707 and the to number signifies the iCode which uses this operand last.
26710 Register Allocation
26711 \begin_inset LatexCommand \index{Register allocation}
26718 The register allocation determines the type and number of registers needed
26720 In most MCUs only a few registers can be used for indirect addressing.
26721 In case of 8051 for example the registers R0 & R1 can be used to indirectly
26722 address the internal ram and DPTR to indirectly address the external ram.
26723 The compiler will try to allocate the appropriate register to pointer variables
26725 ICode example section shows the operands annotated with the registers assigned
26727 The compiler will try to keep operands in registers as much as possible;
26728 there are several schemes the compiler uses to do achieve this.
26729 When the compiler runs out of registers the compiler will check to see
26730 if there are any live operands which is not used or defined in the current
26731 basic block being processed, if there are any found then it will push that
26732 operand and use the registers in this block, the operand will then be popped
26733 at the end of the basic block.
26737 There are other MCU specific considerations in this phase.
26738 Some MCUs have an accumulator; very short-lived operands could be assigned
26739 to the accumulator instead of a general-purpose register.
26745 Figure II gives a table of iCode operations supported by the compiler.
26746 The code generation involves translating these operations into corresponding
26747 assembly code for the processor.
26748 This sounds overly simple but that is the essence of code generation.
26749 Some of the iCode operations are generated on a MCU specific manner for
26750 example, the z80 port does not use registers to pass parameters so the
26751 SEND and RECV iCode operations will not be generated, and it also does
26752 not support JUMPTABLES.
26759 <Where is Figure II?>
26762 In the original article Figure II was announced to be downloadable on
26767 Unfortunately it never seemed to have shown up there, so: where is Figure
26772 \begin_inset LatexCommand \index{iCode}
26779 This section shows some details of iCode.
26780 The example C code does not do anything useful; it is used as an example
26781 to illustrate the intermediate code generated by the compiler.
26793 /* This function does nothing useful.
26800 for the purpose of explaining iCode */
26803 short function (data int *x)
26811 short i=10; \SpecialChar ~
26813 /* dead initialization eliminated */
26818 short sum=10; /* dead initialization eliminated */
26831 while (*x) *x++ = *p++;
26845 /* compiler detects i,j to be induction variables */
26849 for (i = 0, j = 10 ; i < 10 ; i++, j
26875 mul += i * 3; \SpecialChar ~
26877 /* this multiplication remains */
26883 gint += j * 3;\SpecialChar ~
26885 /* this multiplication changed to addition */
26899 In addition to the operands each iCode contains information about the filename
26900 and line it corresponds to in the source file.
26901 The first field in the listing should be interpreted as follows:
26906 Filename(linenumber: iCode Execution sequence number : ICode hash table
26907 key : loop depth of the iCode).
26912 Then follows the human readable form of the ICode operation.
26913 Each operand of this triplet form can be of three basic types a) compiler
26914 generated temporary b) user defined variable c) a constant value.
26915 Note that local variables and parameters are replaced by compiler generated
26918 \begin_inset LatexCommand \index{Live range analysis}
26922 are computed only for temporaries (i.e.
26923 live ranges are not computed for global variables).
26925 \begin_inset LatexCommand \index{Register allocation}
26929 are allocated for temporaries only.
26930 Operands are formatted in the following manner:
26935 Operand Name [lr live-from : live-to ] { type information } [ registers
26941 As mentioned earlier the live ranges are computed in terms of the execution
26942 sequence number of the iCodes, for example
26944 the iTemp0 is live from (i.e.
26945 first defined in iCode with execution sequence number 3, and is last used
26946 in the iCode with sequence number 5).
26947 For induction variables such as iTemp21 the live range computation extends
26948 the lifetime from the start to the end of the loop.
26950 The register allocator used the live range information to allocate registers,
26951 the same registers may be used for different temporaries if their live
26952 ranges do not overlap, for example r0 is allocated to both iTemp6 and to
26953 iTemp17 since their live ranges do not overlap.
26954 In addition the allocator also takes into consideration the type and usage
26955 of a temporary, for example itemp6 is a pointer to near space and is used
26956 as to fetch data from (i.e.
26957 used in GET_VALUE_AT_ADDRESS) so it is allocated a pointer register (r0).
26958 Some short lived temporaries are allocated to special registers which have
26959 meaning to the code generator e.g.
26960 iTemp13 is allocated to a pseudo register CC which tells the back end that
26961 the temporary is used only for a conditional jump the code generation makes
26962 use of this information to optimize a compare and jump ICode.
26964 There are several loop optimizations
26965 \begin_inset LatexCommand \index{Loop optimization}
26969 performed by the compiler.
26970 It can detect induction variables iTemp21(i) and iTemp23(j).
26971 Also note the compiler does selective strength reduction
26972 \begin_inset LatexCommand \index{Strength reduction}
26977 the multiplication of an induction variable in line 18 (gint = j * 3) is
26978 changed to addition, a new temporary iTemp17 is allocated and assigned
26979 a initial value, a constant 3 is then added for each iteration of the loop.
26980 The compiler does not change the multiplication
26981 \begin_inset LatexCommand \index{Multiplication}
26985 in line 17 however since the processor does support an 8 * 8 bit multiplication.
26987 Note the dead code elimination
26988 \begin_inset LatexCommand \index{Dead-code elimination}
26992 optimization eliminated the dead assignments in line 7 & 8 to I and sum
27000 Sample.c (5:1:0:0) _entry($9) :
27005 Sample.c(5:2:1:0) proc _function [lr0:0]{function short}
27010 Sample.c(11:3:2:0) iTemp0 [lr3:5]{_near * int}[r2] = recv
27015 Sample.c(11:4:53:0) preHeaderLbl0($11) :
27020 Sample.c(11:5:55:0) iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near
27026 Sample.c(11:6:5:1) _whilecontinue_0($1) :
27031 Sample.c(11:7:7:1) iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near *
27037 Sample.c(11:8:8:1) if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
27042 Sample.c(11:9:14:1) iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far
27048 Sample.c(11:10:15:1) _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2
27054 Sample.c(11:13:18:1) iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far
27060 Sample.c(11:14:19:1) *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int
27066 Sample.c(11:15:12:1) iTemp6 [lr5:16]{_near * int}[r0] = iTemp6 [lr5:16]{_near
27067 * int}[r0] + 0x2 {short}
27072 Sample.c(11:16:20:1) goto _whilecontinue_0($1)
27077 Sample.c(11:17:21:0)_whilebreak_0($3) :
27082 Sample.c(12:18:22:0) iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
27087 Sample.c(13:19:23:0) iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
27092 Sample.c(15:20:54:0)preHeaderLbl1($13) :
27097 Sample.c(15:21:56:0) iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
27102 Sample.c(15:22:57:0) iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
27107 Sample.c(15:23:58:0) iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
27112 Sample.c(15:24:26:1)_forcond_0($4) :
27117 Sample.c(15:25:27:1) iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4]
27123 Sample.c(15:26:28:1) if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
27128 Sample.c(16:27:31:1) iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2]
27129 + ITemp21 [lr21:38]{short}[r4]
27134 Sample.c(17:29:33:1) iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4]
27140 Sample.c(17:30:34:1) iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3]
27141 + iTemp15 [lr29:30]{short}[r1]
27146 Sample.c(18:32:36:1:1) iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7
27152 Sample.c(18:33:37:1) _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{
27158 Sample.c(15:36:42:1) iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4]
27164 Sample.c(15:37:45:1) iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5
27170 Sample.c(19:38:47:1) goto _forcond_0($4)
27175 Sample.c(19:39:48:0)_forbreak_0($7) :
27180 Sample.c(20:40:49:0) iTemp24 [lr40:41]{short}[DPTR] = iTemp2 [lr18:40]{short}[r2]
27181 + ITemp11 [lr19:40]{short}[r3]
27186 Sample.c(20:41:50:0) ret iTemp24 [lr40:41]{short}
27191 Sample.c(20:42:51:0)_return($8) :
27196 Sample.c(20:43:52:0) eproc _function [lr0:0]{ ia0 re0 rm0}{function short}
27202 Finally the code generated for this function:
27243 ; ----------------------------------------------
27248 ; function function
27253 ; ----------------------------------------------
27263 ; iTemp0 [lr3:5]{_near * int}[r2] = recv
27275 ; iTemp6 [lr5:16]{_near * int}[r0] := iTemp0 [lr3:5]{_near * int}[r2]
27287 ;_whilecontinue_0($1) :
27297 ; iTemp4 [lr7:8]{int}[r2 r3] = @[iTemp6 [lr5:16]{_near * int}[r0]]
27302 ; if iTemp4 [lr7:8]{int}[r2 r3] == 0 goto _whilebreak_0($3)
27361 ; iTemp7 [lr9:13]{_far * int}[DPTR] := _p [lr0:0]{_far * int}
27380 ; _p [lr0:0]{_far * int} = _p [lr0:0]{_far * int} + 0x2 {short}
27427 ; iTemp10 [lr13:14]{int}[r2 r3] = @[iTemp7 [lr9:13]{_far * int}[DPTR]]
27467 ; *(iTemp6 [lr5:16]{_near * int}[r0]) := iTemp10 [lr13:14]{int}[r2 r3]
27493 ; iTemp6 [lr5:16]{_near * int}[r0] =
27498 ; iTemp6 [lr5:16]{_near * int}[r0] +
27515 ; goto _whilecontinue_0($1)
27527 ; _whilebreak_0($3) :
27537 ; iTemp2 [lr18:40]{short}[r2] := 0x0 {short}
27549 ; iTemp11 [lr19:40]{short}[r3] := 0x0 {short}
27561 ; iTemp21 [lr21:38]{short}[r4] := 0x0 {short}
27573 ; iTemp23 [lr22:38]{int}[r5 r6] := 0xa {int}
27592 ; iTemp17 [lr23:38]{int}[r7 r0] := 0x1e {int}
27621 ; iTemp13 [lr25:26]{char}[CC] = iTemp21 [lr21:38]{short}[r4] < 0xa {short}
27626 ; if iTemp13 [lr25:26]{char}[CC] == 0 goto _forbreak_0($7)
27671 ; iTemp2 [lr18:40]{short}[r2] = iTemp2 [lr18:40]{short}[r2] +
27676 ; iTemp21 [lr21:38]{short}[r4]
27702 ; iTemp15 [lr29:30]{short}[r1] = iTemp21 [lr21:38]{short}[r4] * 0x3 {short}
27735 ; iTemp11 [lr19:40]{short}[r3] = iTemp11 [lr19:40]{short}[r3] +
27740 ; iTemp15 [lr29:30]{short}[r1]
27759 ; iTemp17 [lr23:38]{int}[r7 r0]= iTemp17 [lr23:38]{int}[r7 r0]- 0x3 {short}
27806 ; _gint [lr0:0]{int} = _gint [lr0:0]{int} + iTemp17 [lr23:38]{int}[r7 r0]
27853 ; iTemp21 [lr21:38]{short}[r4] = iTemp21 [lr21:38]{short}[r4] + 0x1 {short}
27865 ; iTemp23 [lr22:38]{int}[r5 r6]= iTemp23 [lr22:38]{int}[r5 r6]- 0x1 {short}
27879 cjne r5,#0xff,00104$
27891 ; goto _forcond_0($4)
27903 ; _forbreak_0($7) :
27913 ; ret iTemp24 [lr40:41]{short}
27956 A few words about basic block successors, predecessors and dominators
27959 Successors are basic blocks
27960 \begin_inset LatexCommand \index{Basic blocks}
27964 that might execute after this basic block.
27966 Predecessors are basic blocks that might execute before reaching this basic
27969 Dominators are basic blocks that WILL execute before reaching this basic
28003 a) succList of [BB2] = [BB4], of [BB3] = [BB4], of [BB1] = [BB2,BB3]
28006 b) predList of [BB2] = [BB1], of [BB3] = [BB1], of [BB4] = [BB2,BB3]
28009 c) domVect of [BB4] = BB1 ...
28010 here we are not sure if BB2 or BB3 was executed but we are SURE that BB1
28018 \begin_inset LatexCommand \url{http://sdcc.sourceforge.net#Who}
28028 Thanks to all the other volunteer developers who have helped with coding,
28029 testing, web-page creation, distribution sets, etc.
28030 You know who you are :-)
28037 This document was initially written by Sandeep Dutta
28040 All product names mentioned herein may be trademarks
28041 \begin_inset LatexCommand \index{Trademarks}
28045 of their respective companies.
28052 To avoid confusion, the installation and building options for SDCC itself
28053 (chapter 2) are not part of the index.
28057 \begin_inset LatexCommand \printindex{}