-#LyX 1.4.3 created this file. For more info see http://www.lyx.org/
+#LyX 1.4.5 created this file. For more info see http://www.lyx.org/
\lyxformat 245
\begin_document
\begin_header
\begin_body
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
\begin_layout Standard
Two resp.
- three consecutive dashes simply result in a long resp.
+ three consecutive dashes would otherwise result in a long resp.
extra long dash.
\end_layout
\begin_layout Date
\size normal
-SDCC 2.6.4
+SDCC 2.8.4
\size footnotesize
\newline
-$Date$
+$Date:: $
\newline
$Revision$
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
\emph on
C
\emph default
-ompiler) is an open source, retargettable, optimizing ANSI-C compiler by
-
+ompiler) is free open source, retargettable, optimizing ANSI-C compiler
+ by
\series bold
Sandeep Dutta
\series default
\newline
\newline
-SDCC also comes with a companion source level debugger SDCDB, the debugger
- currently uses ucSim a freeware simulator for 8051 and other micro-controllers.<
+SDCC also comes with a companion source level debugger SDCDB.
+ The debugger currently uses ucSim, a free open source simulator for 8051
+ and other micro-controllers.
\newline
\newline
-
-The latest version can be downloaded from
+The latest SDCC version can be downloaded from
+
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
\end_inset
freeware
\emph default
; source code for all the sub-packages (pre-processor, assemblers, linkers
- etc) is distributed with the package.
- This documentation is maintained using a freeware word processor (LyX).
+ etc.) is distributed with the package.
+ This documentation is maintained using a free open source word processor
+ (LyX).
\newline
-This
- program is free software; you can redistribute it and/or modify it under
- the terms of the GNU General Public License
+This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License
\begin_inset LatexCommand \index{GNU General Public License, GPL}
\end_inset
\end_layout
\begin_layout Standard
-This version has numerous bug fixes compared with the previous version.
- But we also introduced some incompatibilities with older versions.
+Newer versions have usually numerous bug fixes compared with the previous
+ version.
+ But we also sometimes introduce some incompatibilities with older versions.
Not just for the fun of it, but to make the compiler more stable, efficient
and ANSI compliant
\begin_inset LatexCommand \index{ANSI-compliance}
for ANSI-Compliance).
+\begin_inset Note Note
+status collapsed
+
+\begin_layout Standard
+It would be fine to add to each item, in which version was it changed.
+\end_layout
+
+\end_inset
+
+
\newline
\end_layout
\begin_layout Itemize
short is now equivalent to int (16 bits), it used to be equivalent to char
(8 bits) which is not ANSI compliant.
+ To maintain compatibility, old programs may be compiled using the -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-short-is-8bits commandline option (see
+\begin_inset LatexCommand \vref{lyx:--short-is-8bits}
+
+\end_inset
+
+).
\end_layout
\begin_layout Itemize
\end_inset
- functions are casted to int unless explicitly casted
+ functions are casted to int unless explicitly casted and
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-std-c89
+\begin_inset LatexCommand \index{-\/-std-c89}
+
+\end_inset
+
+
+\series default
+and
+\series bold
+ -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-std-c99
+\begin_inset LatexCommand \index{-\/-std-c99}
+
+\end_inset
+
+
+\series default
+ command line option are not defined
\begin_inset Marginal
status collapsed
\family default
\newline
- will push a as an int and as a char resp.
+ will push a as an int and as a char resp if
+\series bold
+ -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-std-c89
+\begin_inset LatexCommand \index{-\/-std-c89}
+
+\end_inset
+
+
+\series default
+and
+\series bold
+ -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-std-c99
+\begin_inset LatexCommand \index{-\/-std-c99}
+
+\end_inset
+
+
+\series default
+ command line options are not defined,
+\newline
+ will push a as two ints if
+\series bold
+ -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-std-c89
+\begin_inset LatexCommand \index{-\/-std-c89}
+
+\end_inset
+
+
+\series default
+or
+\series bold
+ -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-std-c99
+\begin_inset LatexCommand \index{-\/-std-c99}
+
+\end_inset
+
+
+\series default
+ command line option is defined.
\end_layout
\begin_layout Itemize
In previous versions, both forms would have toggled the bit.
\end_layout
-\begin_layout Standard
+\begin_layout Itemize
+in older versions, the preprocessor was always called with -std=c99 regardless
+ of the --std-xxx setting.
+ This is no longer true, and can cause compilation failures on code built
+ with --std-c89 but using c99 preprocessor features, such as one-line (//)
+ comments
+\end_layout
-\emph on
-<pending: more incompatibilities?>
+\begin_layout Itemize
+in versions older then 2.8.4 the pic16 *printf() and printf_tiny() library
+ functions supported undocumented and not standard compliant 'b' binary
+ format specifier ("%b", "%hb" and "%lb").
+ The 'b' specifier is now disabled by default.
+ It can be enabled by defining BINARY_SPECIFIER macro in files device/lib/pic16/
+libc/stdio/vfprintf.c and device/lib/pic16/libc/stdio/printf_tiny.c and recompilin
+g the library.
\end_layout
\begin_layout Section
Some of the other tools (simulator and assembler) included with SDCC contain
their own documentation and can be found in the source distribution.
If you want the latest unreleased software, the complete source package
- is available directly from Subversion on https://svn.sourceforge.net/svnroot/sdcc
-/trunk/sdcc.
+ is available directly from Subversion on https://sdcc.svn.sourceforge.net/svnroot/
+sdcc/trunk/sdcc.
\end_layout
\begin_layout Section
\end_inset
--disable-pic-port Excludes the PIC port
+-disable-pic-port Excludes the PIC14 port
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-disable-pic16-port Excludes the PIC16 port
\end_layout
\begin_layout List
Lower runtime footprint.
\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-without-ccache Do not use ccache even if available
+\end_layout
+
\begin_layout Standard
Furthermore the environment variables CC, CFLAGS, ...
the tools and their arguments can be influenced.
\end_inset
--help` and the man/info pages of `configure` for details.
+-help' and the man/info pages of `configure' for details.
\newline
\newline
The names of the
standard libraries STD_LIB, STD_INT_LIB, STD_LONG_LIB, STD_FP_LIB, STD_DS390_LI
B, STD_XA51_LIB and the environment variables SDCC_DIR_NAME, SDCC_INCLUDE_NAME,
- SDCC_LIB_NAME are defined by `configure` too.
+ SDCC_LIB_NAME are defined by `configure' too.
At the moment it's not possible to change the default settings (it was
simply never required).
\newline
\end_layout
\begin_layout Enumerate
-the binaries can be built by cross compiling on Sourceforge's compile farm.
+the binaries can be built by cross compiling on SDCC Distributed Compile
+ Farm.
\end_layout
\begin_layout Standard
\begin_layout Standard
\noindent
-The install paths can still be changed during `make install` with e.g.:
+The install paths can still be changed during `make install' with e.g.:
\end_layout
\begin_layout LyX-Code
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
\series medium
Download the source package
\series default
- either from the SDCC Subversion repository or from the nightly snapshots
+ either from the SDCC Subversion repository or from snapshot builds
\series medium
, it will be named something like sdcc
\series default
-.src
+-src
\series medium
-.t
+-yyyymmdd-rrrr.t
\series default
ar.
\series medium
-gz
+bz2
\series default
\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/snap.php}
Unpack the file using a command like:
\family sans
\series bold
-"tar -xvzf sdcc.src.tar.gz
+"tar -xvzf sdcc-src-yyyymmdd-rrrr.tar.bz2
+\begin_inset Quotes srd
+\end_inset
+
+
\family default
-\series default
-"
\series medium
, this will create a sub-directory called sdcc with all of the sources.
\end_layout
\end_layout
\begin_layout Subsection
-Building SDCC on OSX 2.x
+Building SDCC on Mac OS X
\end_layout
\begin_layout Standard
\newline
\newline
-On OSX 2.x it was reported, that the default
- gcc (version 3.1 20020420 (prerelease)) fails to compile SDCC.
+On Mac OS X 10.2.x it was reported, that the
+ default gcc (version 3.1 20020420 (prerelease)) fails to compile SDCC.
Fortunately there's also gcc 2.9.x installed, which works fine.
This compiler can be selected by running 'configure' with:
\end_layout
./configure CC=gcc2 CXX=g++2
\end_layout
+\begin_layout Standard
+Universal (ppc and i386) binaries can be produced on Mac OS X 10.4.x with
+ Xcode.
+ Run 'configure' with:
+\end_layout
+
+\begin_layout LyX-Code
+./configure
+\backslash
+
+\end_layout
+
+\begin_layout LyX-Code
+LDFLAGS="-Wl,-syslibroot,/Developer/SDKs/MacOSX10.4u.sdk -arch i386 -arch
+ ppc"
+\backslash
+
+\end_layout
+
+\begin_layout LyX-Code
+CXXFLAGS = "-O2 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch i386 -arch
+ ppc"
+\backslash
+
+\end_layout
+
+\begin_layout LyX-Code
+CFLAGS = "-O2 -isysroot /Developer/SDKs/MacOSX10.4u.sdk -arch i386 -arch ppc"
+\end_layout
+
\begin_layout Subsection
Cross compiling SDCC on Linux for Windows
\end_layout
Download the source package
\series default
either from the SDCC Subversion repository or from the
-\begin_inset LatexCommand \url[nightly snapshots]{http://sdcc.sourceforge.net/snap.php}
+\begin_inset LatexCommand \url[snapshot builds]{http://sdcc.sourceforge.net/snap.php}
\end_inset
\series medium
, it will be named something like sdcc
\series default
-.src
+-src
\series medium
-.tgz.
+-yyyymmdd-rrrr.tar.bz2.
\series default
SDCC is distributed with all the projects, workspaces, and files you need
generated files are not scattered between the source files.
And the best thing is: if you want to change a file you can leave the original
file untouched in the source directory.
- Simply copy it to the build directory, edit it, enter `make clean`, `rm
- Makefile.dep` and `make`.
+ Simply copy it to the build directory, edit it, enter `make clean', `rm
+ Makefile.dep' and `make'.
\series bold
make
\end_inset
- is a freeware, opensource simulator developed by Daniel Drotos.
+ is a free open source simulator developed by Daniel Drotos.
The simulator is built as part of the build process.
For more information visit Daniel's web site at:
\begin_inset LatexCommand \url{http://mazsola.iit.uni-miskolc.hu/~drdani/embedded/s51}
\end_inset
+
+\begin_inset Note Note
+status collapsed
+
+\begin_layout Standard
+hyperlinks needed
+\end_layout
+
+\end_inset
+
+ - see also section
+\begin_inset LatexCommand \vref{sub:Postprocessing-the-Intel}
+
+\end_inset
+
).
Both formats are documented in the documentation of srecord
\begin_inset LatexCommand \index{srecord (bin, hex, ... tool)}
\emph on
f
\emph default
-ormat is commonly used by third party tools (debuggers
+ormat is a subformat of the OMF51 format and is commonly used by third party
+ tools (debuggers
\begin_inset LatexCommand \index{Debugger}
\end_inset
-, simulators, emulators)
+, simulators, emulators).
\end_layout
\begin_layout Itemize
\end_inset
file
+\begin_inset LatexCommand \label{sub:Postprocessing-the-Intel}
+
+\end_inset
+
+
\end_layout
\begin_layout Standard
\family sans
\series bold
sdcclib libint.lib _mulint.rel
+\family default
+\series default
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+Or, if you preffer:
+\family sans
+\series bold
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+sdcclib libint.lib _divsint.rel _divuint.rel _modsint.rel _moduint.rel _mulint.rel
+\family default
\series default
\newline
\begin_layout Standard
If the file already exists in the library, it will be replaced.
- To see what modules and symbols are included in the library, options -s
+ If a list of .rel files is available, you can tell sdcclib to add those
+ files to a library.
+ For example, if the file 'myliblist.txt' contains
+\family sans
+\series bold
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+_divsint.rel
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+_divuint.rel
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+_modsint.rel
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+_moduint.rel
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+_mulint.rel
+\family default
+\series default
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+Use
+\family sans
+\series bold
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+sdcclib -l libint.lib myliblist.txt
+\family default
+\series default
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+Additionally, you can instruct sdcclib to compiles the files before adding
+ them to the library.
+ This is achieved using the environment variables SDCCLIB_CC and/or SDCCLIB_AS.
+ For example:
+\family sans
+\series bold
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+set SDCCLIB_CC=sdcc -c
+\end_layout
+
+\begin_layout Standard
+
+\family sans
+\series bold
+sdcclib -l libint.lib myliblist.txt
+\family default
+\series default
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+To see what modules and symbols are included in the library, options -s
and -m are available.
For example:
\newline
\end_inset
+\begin_inset LatexCommand \label{sec:Command-Line-Options}
+
+\end_inset
+
+
\end_layout
\begin_layout Subsection
\end_inset
-.
+, which is based on AVR-port of the gcc compiler.
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
\series default
- The additional location where the pre processor will look for <..h> or
+ The additional location where the preprocessor will look for <..h> or
\begin_inset Quotes eld
\end_inset
\series bold
-pedantic-parse-number
+\begin_inset LatexCommand \index{pedantic}
+
+\end_inset
+
+
\begin_inset LatexCommand \index{-pedantic-parse-number}
\end_inset
\size large
\bar under
+
+\begin_inset LatexCommand \label{lyx:-pedantic-parse-number}
+
+\end_inset
+
\series default
\size default
\bar default
-Pedentic parse numbers so that situations like 0xfe-LO_B(3) are parsed properly
+Pedantic parse numbers so that situations like 0xfe-LO_B(3) are parsed properly
and the macro LO_B(3) gets expanded.
- See also #pragma pedantic_parse_number in section
+ See also #pragma pedantic_parse_number
+\begin_inset LatexCommand \vpageref{ite:pedantic_parse_number}
+
+\end_inset
+
+ in section
\begin_inset LatexCommand \ref{sec:Pragmas}
\end_inset
\emph on
-Note: this functionality is not in conformance with standard!
+Note: this functionality is not in conformance with C99 standard!
\end_layout
\begin_layout List
\end_inset
+
+\begin_inset LatexCommand \label{lyx:-Wl option}
+
+\end_inset
+
...
Pass the linkOption to the linker.
If a bootloader is used an option like
\end_inset
would be typical to set the start of the code segment.
+ Either use the double quotes around this option or use no space (e.g.
+ -Wl-bCSEG=0x1000).
See also #pragma constseg and #pragma codeseg in section
\begin_inset LatexCommand \ref{sec:Pragmas}
Causes the linker to use old style for allocating memory areas.
\end_layout
-\begin_layout Standard
-\begin_inset VSpace bigskip
-\end_inset
-
-
-\end_layout
-
-\begin_layout Subsection
-DS390 / DS400 Options
-\begin_inset LatexCommand \index{Options DS390}
-
-\end_inset
-
-
-\begin_inset LatexCommand \index{DS390}
-
-\end_inset
-
-
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--model-flat24
-\series default
-
-\begin_inset LatexCommand \index{DS390!Options!-\/-model-flat24}
-
-\end_inset
-
-
-\size large
-\emph on
-
-\size default
-\emph default
-Generate 24-bit flat mode code.
- This is the one and only that the ds390 code generator supports right now
- and is default when using
-\emph on
--mds390
-\emph default
-.
- See section Memory Models for more details.
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--protect-sp-update
-\begin_inset LatexCommand \index{DS390!Options!-\/-protect-sp-update}
-
-\end_inset
-
-
-\series default
- disable interrupts during ESP:SP updates.
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--stack-10bit
-\series default
-
-\begin_inset LatexCommand \index{DS390!Options!-\/-stack-10bit}
-
-\end_inset
-
- Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
- This is the one and only that the ds390 code generator supports right now
- and is default when using
-\emph on
--mds390
-\emph default
-.
- In this mode, the stack is located in the lower 1K of the internal RAM,
- which is mapped to 0x400000.
- Note that the support is incomplete, since it still uses a single byte
- as the stack pointer.
- This means that only the lower 256 bytes of the potential 1K stack space
- will actually be used.
- However, this does allow you to reclaim the precious 256 bytes of low RAM
- for use for the DATA and IDATA segments.
- The compiler will not generate any code to put the processor into 10 bit
- stack mode.
- It is important to ensure that the processor is in this mode before calling
- any re-entrant functions compiled with this option.
- In principle, this should work with the
-\emph on
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--stack-auto
-\begin_inset LatexCommand \index{-\/-stack-auto}
-
-\end_inset
-
-
-\emph default
- option, but that has not been tested.
- It is incompatible with the
-\emph on
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--xstack
-\begin_inset LatexCommand \index{-\/-xstack}
-
-\end_inset
-
-
-\emph default
- option.
- It also only makes sense if the processor is in 24 bit contiguous addressing
- mode (see the
-\emph on
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--model-flat24 option
-\emph default
-).
-\end_layout
-
\begin_layout List
\labelwidthstring 00.00.0000
\end_inset
--stack-probe
-\begin_inset LatexCommand \index{DS390!Options!-\/-stack-probe}
-
-\end_inset
-
-
+-acall-ajmp
\series default
- insert call to function __stack_probe at each function prologue.
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--tini-libid
-\begin_inset LatexCommand \index{DS390!Options!-\/-tini-libid}
-
-\end_inset
-
-
-\series default
- <nnnn> LibraryID used in -mTININative.
-
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
+\InsetSpace ~
-\end_inset
-
--use-accelerator
-\begin_inset LatexCommand \index{DS390!Options!-\/-use-accelerator}
+\begin_inset LatexCommand \index{-\/-acall-ajmp}
\end_inset
-
-\series default
- generate code for DS390 Arithmetic Accelerator.
-
+ Replaces the three byte instructions lcall/ljmp with the two byte instructions
+ acall/ajmp.
+ Only use this option if your code is in the same 2k block of memory.
+ You may need to use this option for some 8051 derivatives which lack the
+ lcall/ljmp instructions..
\end_layout
\begin_layout Standard
\end_layout
\begin_layout Subsection
-Z80 Options
-\begin_inset LatexCommand \index{Options Z80}
+DS390 / DS400 Options
+\begin_inset LatexCommand \index{Options DS390}
\end_inset
-\begin_inset LatexCommand \index{Z80}
+\begin_inset LatexCommand \index{DS390}
\end_inset
\end_inset
--callee-saves-bc
+-model-flat24
\series default
-\begin_inset LatexCommand \index{Z80!Options!-\/-callee-saves-bc}
+\begin_inset LatexCommand \index{DS390!Options!-\/-model-flat24}
\end_inset
\size default
\emph default
-Force a called function to always save BC.
+Generate 24-bit flat mode code.
+ This is the one and only that the ds390 code generator supports right now
+ and is default when using
+\emph on
+-mds390
+\emph default
+.
+ See section Memory Models for more details.
\end_layout
\begin_layout List
\end_inset
--no-std-crt0
-\series default
-
-\begin_inset LatexCommand \index{Z80!Options!-\/-no-std-crt0}
-
-\end_inset
-
- When linking, skip the standard crt0.o object file.
- You must provide your own crt0.o for your system when linking.
-
-\end_layout
-
-\begin_layout Standard
-\begin_inset VSpace bigskip
-\end_inset
-
-
-\end_layout
-
-\begin_layout Subsection
-Optimization Options
-\begin_inset LatexCommand \index{Options optimization}
-
-\end_inset
-
-
-\begin_inset LatexCommand \index{Optimization options}
+-protect-sp-update
+\begin_inset LatexCommand \index{DS390!Options!-\/-protect-sp-update}
\end_inset
+\series default
+ disable interrupts during ESP:SP updates.
\end_layout
\begin_layout List
\end_inset
--nogcse
-\begin_inset LatexCommand \index{-\/-nogcse}
+-stack-10bit
+\series default
-\end_inset
+\begin_inset LatexCommand \index{DS390!Options!-\/-stack-10bit}
+\end_inset
-\series default
- Will not do global subexpression elimination, this option may be used when
- the compiler creates undesirably large stack/data spaces to store compiler
- temporaries (
+ Generate code for the 10 bit stack mode of the Dallas DS80C390 part.
+ This is the one and only that the ds390 code generator supports right now
+ and is default when using
\emph on
-s
+-mds390
\emph default
-pill
+.
+ In this mode, the stack is located in the lower 1K of the internal RAM,
+ which is mapped to 0x400000.
+ Note that the support is incomplete, since it still uses a single byte
+ as the stack pointer.
+ This means that only the lower 256 bytes of the potential 1K stack space
+ will actually be used.
+ However, this does allow you to reclaim the precious 256 bytes of low RAM
+ for use for the DATA and IDATA segments.
+ The compiler will not generate any code to put the processor into 10 bit
+ stack mode.
+ It is important to ensure that the processor is in this mode before calling
+ any re-entrant functions compiled with this option.
+ In principle, this should work with the
\emph on
-loc
-\emph default
-ations, sloc
-\begin_inset LatexCommand \index{sloc (spill location)}
+-
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-).
- A warning message will be generated when this happens and the compiler
- will indicate the number of extra bytes it allocated.
- It is recommended that this option NOT be used, #pragma\InsetSpace ~
-nogcse
-\begin_inset LatexCommand \index{\#pragma nogcse}
+
+\backslash
+/
+\end_layout
\end_inset
- can be used to turn off global subexpression elimination
-\begin_inset LatexCommand \index{Subexpression elimination}
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
\end_inset
- for a given function only.
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-\series bold
+\emph default
+ option, but that has not been tested.
+ It is incompatible with the
+\emph on
-
\begin_inset ERT
status collapsed
\end_inset
--noinvariant
-\begin_inset LatexCommand \index{-\/-noinvariant}
+-xstack
+\begin_inset LatexCommand \index{-\/-xstack}
\end_inset
-\series default
- Will not do loop invariant optimizations, this may be turned off for reasons
- explained for the previous option.
- For more details of loop optimizations performed see Loop Invariants in
- section
-\begin_inset LatexCommand \ref{sub:Loop-Optimizations}
+\emph default
+ option.
+ It also only makes sense if the processor is in 24 bit contiguous addressing
+ mode (see the
+\emph on
+-
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-.
- It is recommended that this option NOT be used, #pragma\InsetSpace ~
-noinvariant
-\begin_inset LatexCommand \index{\#pragma noinvariant}
+
+\backslash
+/
+\end_layout
\end_inset
- can be used to turn off invariant optimizations for a given function only.
-\end_layout
+-model-flat24 option
+\emph default
+).
+\series bold
+
+\begin_inset Note Note
+status collapsed
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
-
\begin_inset ERT
-status collapsed
+status open
\begin_layout Standard
\end_inset
--noinduction
-\begin_inset LatexCommand \index{-\/-noinduction}
+-stack-8-bit - switches off the 10-bit mode
+\end_layout
\end_inset
-\series default
- Will not do loop induction optimizations, see section strength reduction
- for more details.
- It is recommended that this option is NOT used, #pragma\InsetSpace ~
-noinduction
-\begin_inset LatexCommand \index{\#pragma noinduction}
-
-\end_inset
-
- can be used to turn off induction optimizations for a given function only.
\end_layout
\begin_layout List
\end_inset
--nojtbound
-\begin_inset LatexCommand \index{-\/-nojtbound}
+-stack-probe
+\begin_inset LatexCommand \index{DS390!Options!-\/-stack-probe}
\end_inset
-\size large
-\bar under
-
\series default
-\size default
-\bar default
- Will not generate boundary condition check when switch statements
-\begin_inset LatexCommand \index{switch statement}
-
-\end_inset
-
- are implemented using jump-tables.
- See section
-\begin_inset LatexCommand \ref{sub:'switch'-Statements}
-
-\end_inset
-
-\InsetSpace ~
-Switch Statements for more details.
- It is recommended that this option is NOT used, #pragma\InsetSpace ~
-nojtbound
-\begin_inset LatexCommand \index{\#pragma nojtbound}
-
-\end_inset
-
- can be used to turn off boundary checking for jump tables for a given function
- only.
+ insert call to function __stack_probe at each function prologue.
\end_layout
\begin_layout List
\series bold
-
\begin_inset ERT
-status collapsed
+status open
\begin_layout Standard
\end_inset
--noloopreverse
-\begin_inset LatexCommand \index{-\/-noloopreverse}
+-tini-libid
+\begin_inset LatexCommand \index{DS390!Options!-\/-tini-libid}
\end_inset
\series default
-\size large
+ <nnnn> LibraryID used in -mTININative.
-\size default
-Will not do loop reversal
-\begin_inset LatexCommand \index{Loop reversing}
-
-\end_inset
-
-optimization.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
+
+\series bold
-
\begin_inset ERT
status collapsed
\end_inset
--
-\series bold
-nolabelopt
-\series default
-
-\begin_inset LatexCommand \index{-\/-nolabelopt }
+-use-accelerator
+\begin_inset LatexCommand \index{DS390!Options!-\/-use-accelerator}
\end_inset
-Will not optimize labels (makes the dumpfiles more readable).
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-\series bold
--
-\begin_inset ERT
-status collapsed
+\series default
+ generate code for DS390 Arithmetic Accelerator.
+
+\end_layout
\begin_layout Standard
+\begin_inset VSpace bigskip
+\end_inset
-\backslash
-/
\end_layout
-\end_inset
-
--no-xinit-opt
-\begin_inset LatexCommand \index{-\/-no-xinit-opt}
+\begin_layout Subsection
+Z80 Options
+\begin_inset LatexCommand \index{Options Z80}
\end_inset
-\series default
- Will not memcpy initialized data from code space into xdata space.
- This saves a few bytes in code space if you don't have initialized data
-\begin_inset LatexCommand \index{Variable initialization}
+\begin_inset LatexCommand \index{Z80}
\end_inset
-.
+
\end_layout
\begin_layout List
\end_inset
--nooverlay
-\begin_inset LatexCommand \index{-\/-nooverlay}
+-callee-saves-bc
+\series default
+
+\begin_inset LatexCommand \index{Z80!Options!-\/-callee-saves-bc}
\end_inset
-\series default
- The compiler will not overlay parameters and local variables of any function,
- see section Parameters and local variables for more details.
+\size large
+\emph on
+
+\size default
+\emph default
+Force a called function to always save BC.
\end_layout
\begin_layout List
\end_inset
--no-peep
-\begin_inset LatexCommand \index{-\/-no-peep}
+-no-std-crt0
+\series default
-\end_inset
+\begin_inset LatexCommand \index{Z80!Options!-\/-no-std-crt0}
+\end_inset
-\series default
- Disable peep-hole optimization with built-in rules.
+ When linking, skip the standard crt0.o object file.
+ You must provide your own crt0.o for your system when linking.
\end_layout
\begin_layout List
\end_inset
--peep-file
+-portmode=
\series default
-
-\begin_inset LatexCommand \index{-\/-peep-file}
-
-\end_inset
-
-\InsetSpace ~
-<filename> This option can be used to use additional rules to be used by
- the peep hole optimizer.
- See section
-\begin_inset LatexCommand \ref{sub:Peephole-Optimizer}
+<Value>
+\begin_inset LatexCommand \index{Z80!Options!-\/-portmode=<Value>}
\end_inset
-\InsetSpace ~
-Peep Hole optimizations for details on how to write these rules.
+ Determinate PORT I/O mode (<Value> is z80 or z180).
\end_layout
\begin_layout List
\end_inset
--peep-asm
-\begin_inset LatexCommand \index{-\/-peep-asm}
-
-\end_inset
-
-
+-asm=
\series default
- Pass the inline assembler code through the peep hole optimizer.
- This can cause unexpected changes to inline assembler code, please go through
- the peephole optimizer
-\begin_inset LatexCommand \index{Peephole optimizer}
+<Value>
+\begin_inset LatexCommand \index{Z80!Options!-\/-asm=<Value>}
\end_inset
- rules defined in the source file tree '<target>/peeph.def' before using
- this option.
+ Define assembler name (<Value> is rgbds, asxxxx, isas or z80asm).
\end_layout
\begin_layout List
\end_inset
--opt-code-speed
-\begin_inset LatexCommand \index{-\/-opt-code-speed}
+-codeseg
+\series default
+\InsetSpace ~
+<Value>
+\begin_inset LatexCommand \index{Z80!Options!-\/-codeseg <Value>}
\end_inset
-
-\series default
- The compiler will optimize code generation towards fast code, possibly
- at the expense of code size.
+ Use <Value> for the code segment name.
\end_layout
\begin_layout List
\end_inset
--opt-code-size
-\begin_inset LatexCommand \index{-\/-opt-code-size}
+-constseg
+\series default
+\InsetSpace ~
+<Value>
+\begin_inset LatexCommand \index{Z80!Options!-\/-constseg <Value>}
\end_inset
-
-\series default
- The compiler will optimize code generation towards compact code, possibly
- at the expense of code speed.
+ Use <Value> for the const segment name.
\end_layout
-\begin_layout Standard
+\begin_layout List
+\labelwidthstring 00.00.0000
\begin_inset VSpace bigskip
\end_inset
\end_layout
\begin_layout Subsection
-Other Options
-\begin_inset LatexCommand \index{Options other}
+GBZ80 Options
+\begin_inset LatexCommand \index{Options GBZ80}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{GBZ80}
\end_inset
\labelwidthstring 00.00.0000
\series bold
--c\InsetSpace ~
-
\begin_inset ERT
status collapsed
\end_inset
--compile-only
-\begin_inset LatexCommand \index{-\/-compile-only}
-
-\end_inset
-
+-callee-saves-bc
+\series default
-\begin_inset LatexCommand \index{-c -\/-compile-only}
+\begin_inset LatexCommand \index{GBZ80!Options!-\/-callee-saves-bc}
\end_inset
-\series default
- will compile and assemble the source, but will not call the linkage editor.
+\size large
+\emph on
+
+\size default
+\emph default
+Force a called function to always save BC.
\end_layout
\begin_layout List
\series bold
-
-\series default
-
\begin_inset ERT
status collapsed
\end_inset
+-no-std-crt0
+\series default
-\series bold
--c1mode
-\begin_inset LatexCommand \index{-\/-c1mode}
+\begin_inset LatexCommand \index{Z80!Options!-\/-no-std-crt0}
\end_inset
-
-\series default
- reads the preprocessed source from standard input and compiles it.
- The file name for the assembler output must be specified using the -o option.
+ When linking, skip the standard crt0.o object file.
+ You must provide your own crt0.o for your system when linking.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
--E
-\begin_inset LatexCommand \index{-E}
+-bo
+\series default
+\InsetSpace ~
+<Num>
+\begin_inset LatexCommand \index{GBZ80!Options!-bo <Num>}
\end_inset
+ Use code bank <Num>.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+\series bold
+-ba
\series default
- Run only the C preprocessor.
- Preprocess all the C source files specified and output the results to standard
- output.
+\InsetSpace ~
+<Num>
+\begin_inset LatexCommand \index{GBZ80!Options!-ba <Num>}
+
+\end_inset
+
+ Use data bank <Num>.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
--o\InsetSpace ~
-<path/file>
-\begin_inset LatexCommand \index{-o <path/file>}
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
\end_inset
-
+-codeseg
\series default
-The output path resp.
- file where everything will be placed.
- If the parameter is a path, it must have a trailing slash (or backslash
- for the Windows binaries) to be recognized as a path.
-
+\InsetSpace ~
+<Value>
+\begin_inset LatexCommand \index{GBZ80!Options!-\/-codeseg <Value>}
+
+\end_inset
+
+ Use <Value> for the code segment name.
\end_layout
\begin_layout List
\end_inset
--stack-auto
-\begin_inset LatexCommand \index{-\/-stack-auto}
+-constseg
+\series default
+\InsetSpace ~
+<Value>
+\begin_inset LatexCommand \index{GBZ80!Options!-\/-constseg <Value>}
\end_inset
+ Use <Value> for the const segment name.
+\end_layout
-\series default
-\size large
-\emph on
-
-\size default
-\emph default
-All functions in the source file will be compiled as
-\emph on
-reentrant
-\emph default
+\begin_layout Standard
+\begin_inset VSpace bigskip
+\end_inset
-\begin_inset LatexCommand \index{reentrant}
-\end_inset
+\end_layout
-, i.e.
- the parameters and local variables will be allocated on the stack
-\begin_inset LatexCommand \index{stack}
+\begin_layout Subsection
+Optimization Options
+\begin_inset LatexCommand \index{Options optimization}
\end_inset
-.
- See section
-\begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
+
+\begin_inset LatexCommand \index{Optimization options}
\end_inset
- Parameters and Local Variables for more details.
- If this option is used all source files in the project should be compiled
- with this option.
- It automatically implies --int-long-reent and --float-reent.
-
+
\end_layout
\begin_layout List
\end_inset
--callee-saves
-\begin_inset LatexCommand \index{-\/-callee-saves}
+-nogcse
+\begin_inset LatexCommand \index{-\/-nogcse}
\end_inset
- function1[,function2][,function3]....
\series default
- The compiler by default uses a caller saves convention for register saving
- across function calls, however this can cause unnecessary register pushing
- & popping when calling small functions from larger functions.
- This option can be used to switch the register saving convention for the
- function names specified.
- The compiler will not save registers when calling these functions, no extra
- code will be generated at the entry & exit (function prologue
-\series bold
-
-\begin_inset LatexCommand \index{function prologue}
+ Will not do global subexpression elimination, this option may be used when
+ the compiler creates undesirably large stack/data spaces to store compiler
+ temporaries (
+\emph on
+s
+\emph default
+pill
+\emph on
+loc
+\emph default
+ations, sloc
+\begin_inset LatexCommand \index{sloc (spill location)}
\end_inset
+).
+ A warning message will be generated when this happens and the compiler
+ will indicate the number of extra bytes it allocated.
+ It is recommended that this option NOT be used, #pragma\InsetSpace ~
+nogcse
+\begin_inset LatexCommand \index{\#pragma nogcse}
-\series default
- & epilogue
-\series bold
+\end_inset
-\begin_inset LatexCommand \index{function epilogue}
+ can be used to turn off global subexpression elimination
+\begin_inset LatexCommand \index{Subexpression elimination}
\end_inset
+ for a given function only.
+\end_layout
-\series default
-) for these functions to save & restore the registers used by these functions,
- this can SUBSTANTIALLY reduce code & improve run time performance of the
- generated code.
- In the future the compiler (with inter procedural analysis) will be able
- to determine the appropriate scheme to use for each function call.
- DO NOT use this option for built-in functions such as _mulint..., if this
- option is used for a library function the appropriate library function
- needs to be recompiled with the same option.
- If the project consists of multiple source files then all the source file
- should be compiled with the same -
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
\begin_inset ERT
status collapsed
\end_inset
--callee-saves option string.
- Also see #pragma\InsetSpace ~
-callee_saves
-\begin_inset LatexCommand \index{\#pragma callee\_saves}
+-noinvariant
+\begin_inset LatexCommand \index{-\/-noinvariant}
+
+\end_inset
+
+
+\series default
+ Will not do loop invariant optimizations, this may be turned off for reasons
+ explained for the previous option.
+ For more details of loop optimizations performed see Loop Invariants in
+ section
+\begin_inset LatexCommand \ref{sub:Loop-Optimizations}
\end_inset
.
+ It is recommended that this option NOT be used, #pragma\InsetSpace ~
+noinvariant
+\begin_inset LatexCommand \index{\#pragma noinvariant}
+
+\end_inset
+
+ can be used to turn off invariant optimizations for a given function only.
\end_layout
\begin_layout List
\end_inset
--debug
-\begin_inset LatexCommand \index{-\/-debug}
+-noinduction
+\begin_inset LatexCommand \index{-\/-noinduction}
\end_inset
-\bar under
-
\series default
-\bar default
-When this option is used the compiler will generate debug information.
- The debug information collected in a file with .cdb extension can be used
- with the SDCDB.
- For more information see documentation for SDCDB.
- Another file with no extension contains debug information in AOMF or AOMF51
-\begin_inset LatexCommand \index{AOMF, AOMF51}
+ Will not do loop induction optimizations, see section strength reduction
+ for more details.
+ It is recommended that this option is NOT used, #pragma\InsetSpace ~
+noinduction
+\begin_inset LatexCommand \index{\#pragma noinduction}
\end_inset
- format which is commonly used by third party tools.
+ can be used to turn off induction optimizations for a given function only.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
--S
-\begin_inset LatexCommand \index{-S}
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-nojtbound
+\begin_inset LatexCommand \index{-\/-nojtbound}
\end_inset
\series default
\size default
\bar default
-Stop after the stage of compilation proper; do not assemble.
- The output is an assembler code file for the input file specified.
+ Will not generate boundary condition check when switch statements
+\begin_inset LatexCommand \index{switch statement}
+
+\end_inset
+
+ are implemented using jump-tables.
+ See section
+\begin_inset LatexCommand \ref{sub:'switch'-Statements}
+
+\end_inset
+
+\InsetSpace ~
+Switch Statements for more details.
+ It is recommended that this option is NOT used, #pragma\InsetSpace ~
+nojtbound
+\begin_inset LatexCommand \index{\#pragma nojtbound}
+
+\end_inset
+
+ can be used to turn off boundary checking for jump tables for a given function
+ only.
\end_layout
\begin_layout List
\end_inset
--int-long-reent
-\begin_inset LatexCommand \index{-\/-int-long-reent}
+-noloopreverse
+\begin_inset LatexCommand \index{-\/-noloopreverse}
\end_inset
\series default
- Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
- Note by default these libraries are compiled as non-reentrant.
- See section Installation for more details.
+\size large
+
+\size default
+Will not do loop reversal
+\begin_inset LatexCommand \index{Loop reversing}
+
+\end_inset
+
+optimization.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
-
-\series bold
-
\begin_inset ERT
status collapsed
\end_inset
--cyclomatic
-\begin_inset LatexCommand \index{-\/-cyclomatic}
-
-\end_inset
-
-
-\bar under
-
+-
+\series bold
+nolabelopt
\series default
-\bar default
-This option will cause the compiler to generate an information message for
- each function in the source file.
- The message contains some
-\emph on
-important
-\emph default
- information about the function.
- The number of edges and nodes the compiler detected in the control flow
- graph of the function, and most importantly the
-\emph on
-cyclomatic complexity
-\begin_inset LatexCommand \index{Cyclomatic complexity}
+
+\begin_inset LatexCommand \index{-\/-nolabelopt }
\end_inset
-
-\emph default
- see section on Cyclomatic Complexity for more details.
+Will not optimize labels (makes the dumpfiles more readable).
\end_layout
\begin_layout List
\end_inset
--float-reent
-\begin_inset LatexCommand \index{-\/-float-reent}
+-no-xinit-opt
+\begin_inset LatexCommand \index{-\/-no-xinit-opt}
\end_inset
\series default
- Floating point library is compiled as reentrant
-\begin_inset LatexCommand \index{reentrant}
+ Will not memcpy initialized data from code space into xdata space.
+ This saves a few bytes in code space if you don't have initialized data
+\begin_inset LatexCommand \index{Variable initialization}
\end_inset
.
- See section Installation for more details.
\end_layout
\begin_layout List
\end_inset
--main-return
-\begin_inset LatexCommand \index{-\/-main-return}
+-nooverlay
+\begin_inset LatexCommand \index{-\/-nooverlay}
\end_inset
\series default
- This option can be used if the code generated is called by a monitor program
- or if the main routine includes an endless loop.
- This option results in slightly smaller code and saves two bytes of stack
- space.
- The return from the 'main'
-\begin_inset LatexCommand \index{main return}
-
-\end_inset
-
- function will return to the function calling main.
- The default setting is to lock up i.e.
- generate a '
-\family typewriter
-sjmp .
-\family default
-'.
+ The compiler will not overlay parameters and local variables of any function,
+ see section Parameters and local variables for more details.
\end_layout
\begin_layout List
\end_inset
--nostdinc
-\begin_inset LatexCommand \index{-\/-nostdinc}
+-no-peep
+\begin_inset LatexCommand \index{-\/-no-peep}
\end_inset
\series default
- This will prevent the compiler from passing on the default include path
- to the preprocessor.
+ Disable peep-hole optimization with built-in rules.
\end_layout
\begin_layout List
\end_inset
--nostdlib
-\begin_inset LatexCommand \index{-\/-nostdlib}
+-peep-file
+\series default
-\end_inset
+\begin_inset LatexCommand \index{-\/-peep-file}
+\end_inset
-\series default
- This will prevent the compiler from passing on the default library
-\begin_inset LatexCommand \index{Libraries}
+\InsetSpace ~
+<filename> This option can be used to use additional rules to be used by
+ the peep hole optimizer.
+ See section
+\begin_inset LatexCommand \ref{sub:Peephole-Optimizer}
\end_inset
- path to the linker.
+\InsetSpace ~
+Peep Hole optimizations for details on how to write these rules.
\end_layout
\begin_layout List
\end_inset
--verbose
-\begin_inset LatexCommand \index{-\/-verbose}
+-peep-asm
+\begin_inset LatexCommand \index{-\/-peep-asm}
\end_inset
\series default
- Shows the various actions the compiler is performing.
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--V
-\begin_inset LatexCommand \index{-V}
+ Pass the inline assembler code through the peep hole optimizer.
+ This can cause unexpected changes to inline assembler code, please go through
+ the peephole optimizer
+\begin_inset LatexCommand \index{Peephole optimizer}
\end_inset
-
-\series default
- Shows the actual commands the compiler is executing.
+ rules defined in the source file tree '<target>/peeph.def' before using
+ this option.
\end_layout
\begin_layout List
\end_inset
--no-c-code-in-asm
-\begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
+-opt-code-speed
+\begin_inset LatexCommand \index{-\/-opt-code-speed}
\end_inset
\series default
- Hides your ugly and inefficient c-code from the asm file, so you can always
- blame the compiler :)
+ The compiler will optimize code generation towards fast code, possibly
+ at the expense of code size.
\end_layout
\begin_layout List
\end_inset
--no-peep-comments
-\begin_inset LatexCommand \index{-\/-no-peep-comments}
+-opt-code-size
+\begin_inset LatexCommand \index{-\/-opt-code-size}
\end_inset
\series default
- Will not include peep-hole comments in the generated files.
+ The compiler will optimize code generation towards compact code, possibly
+ at the expense of code speed.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--
-\begin_inset ERT
-status collapsed
-
\begin_layout Standard
+\begin_inset VSpace bigskip
+\end_inset
-\backslash
-/
\end_layout
-\end_inset
-
--i-code-in-asm
-\begin_inset LatexCommand \index{-\/-i-code-in-asm}
+\begin_layout Subsection
+Other Options
+\begin_inset LatexCommand \index{Options other}
\end_inset
-\series default
- Include i-codes in the asm file.
- Sounds like noise but is most helpful for debugging the compiler itself.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
+-c\InsetSpace ~
-
\begin_inset ERT
status collapsed
\end_inset
--less-pedantic
-\begin_inset LatexCommand \index{-\/-less-pedantic}
+-compile-only
+\begin_inset LatexCommand \index{-\/-compile-only}
\end_inset
-\series default
- Disable some of the more pedantic warnings
-\begin_inset LatexCommand \index{Warnings}
+\begin_inset LatexCommand \index{-c -\/-compile-only}
\end_inset
- (jwk burps: please be more specific here, please!).
+
+\series default
+ will compile and assemble the source, but will not call the linkage editor.
\end_layout
\begin_layout List
\series bold
-
+\series default
+
\begin_inset ERT
status collapsed
\end_inset
--disable-warning\InsetSpace ~
-<nnnn>
-\begin_inset LatexCommand \index{-\/-disable-warning}
+
+\series bold
+-c1mode
+\begin_inset LatexCommand \index{-\/-c1mode}
\end_inset
\series default
- Disable specific warning with number <nnnn>.
+ reads the preprocessed source from standard input and compiles it.
+ The file name for the assembler output must be specified using the -o option.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--print-search-dirs
-\begin_inset LatexCommand \index{-\/-print-search-dirs}
+-E
+\begin_inset LatexCommand \index{-E}
\end_inset
\series default
- Display the directories in the compiler's search path
+ Run only the C preprocessor.
+ Preprocess all the C source files specified and output the results to standard
+ output.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
--
-\begin_inset ERT
-status collapsed
+-o\InsetSpace ~
+<path/file>
+\begin_inset LatexCommand \index{-o <path/file>}
-\begin_layout Standard
+\end_inset
+
+
+\series default
+The output path where everything will be placed or the file name used for
+ all generated output files.
+ If the parameter is a path, it must have a trailing slash (or backslash
+ for the Windows binaries) to be recognized as a path.
+\emph on
+
+\emph default
+Note for Windows users: if the path contains spaces, it should be surrounded
+ by quotes.
+ The trailing backslash should be doubled in order to prevent escaping the
+ final quote, for example:
+\emph on
+-o
+\begin_inset Quotes sld
+\end_inset
+F:
+\backslash
+Projects
+\backslash
+test3
+\backslash
+output 1
\backslash
-/
-\end_layout
+\backslash
+
+\begin_inset Quotes srd
\end_inset
--vc
-\begin_inset LatexCommand \index{-\/-vc}
+\emph default
+ or put after the final quote, for example:
+\emph on
+-o
+\begin_inset Quotes sld
\end_inset
+F:
+\backslash
+Projects
+\backslash
+test3
+\backslash
+output 1
+\begin_inset Quotes srd
+\end_inset
-\series default
- Display errors and warnings using MSVC style, so you can use SDCC with
- the visual studio IDE
-\begin_inset LatexCommand \index{IDE}
-\end_inset
+\backslash
+\emph default
.
- With SDCC both offering a GCC-like (the default) and a MSVC-like
-\begin_inset LatexCommand \index{MSVC output style}
+ The path using slashes for directory delimiters can be used too, for example:
+
+\emph on
+-o
+\begin_inset Quotes sld
+\end_inset
+F:/Projects/test3/output 1/
+\begin_inset Quotes srd
\end_inset
- output style, integration into most programming editors should be straightforwa
-rd.
+
+\emph default
+.
\end_layout
\begin_layout List
\end_inset
--use-stdout
-\begin_inset LatexCommand \index{-\/-use-stdout}
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
\end_inset
\series default
- Send errors and warnings to stdout instead of stderr.
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--Wa\InsetSpace ~
-asmOption[,asmOption]
-\series default
-
-\begin_inset LatexCommand \index{-Wa asmOption[,asmOption]}
-
-\end_inset
+\size large
+\emph on
+
+\size default
+\emph default
+All functions in the source file will be compiled as
+\emph on
+reentrant
+\emph default
-...
- Pass the asmOption to the assembler
-\begin_inset LatexCommand \index{Options assembler}
+\begin_inset LatexCommand \index{reentrant}
\end_inset
-
-\begin_inset LatexCommand \index{Assembler options}
+, i.e.
+ the parameters and local variables will be allocated on the stack
+\begin_inset LatexCommand \index{stack}
\end_inset
.
- See file sdcc/as/doc/asxhtm.html for assembler options.cd
-\end_layout
+ See section
+\begin_inset LatexCommand \ref{sec:Parameters-and-Local-Variables}
-\begin_layout List
-\labelwidthstring 00.00.0000
+\end_inset
+ Parameters and Local Variables for more details.
+ If this option is used all source files in the project should be compiled
+ with this option.
+ It automatically implies -
\series bold
--
+
\begin_inset ERT
-status collapsed
+status open
\begin_layout Standard
\end_inset
--std-sdcc89
-\begin_inset LatexCommand \index{-\/-std-sdcc89}
-
-\end_inset
-
\series default
- Generally follow the C89 standard, but allow SDCC features that conflict
- with the standard (default).
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
+-int-long-reent and -
\series bold
--
+
\begin_inset ERT
-status collapsed
+status open
\begin_layout Standard
\end_inset
--std-c89
-\begin_inset LatexCommand \index{-\/-std-c89}
-
-\end_inset
-
\series default
- Follow the C89 standard and disable SDCC features that conflict with the
- standard.
+-float-reent.
+
\end_layout
\begin_layout List
\end_inset
--std-sdcc99
-\begin_inset LatexCommand \index{-\/-std-sdcc99}
+-callee-saves
+\begin_inset LatexCommand \index{-\/-callee-saves}
\end_inset
+
+\begin_inset LatexCommand \label{lyx:--callee-saves-function1[,function2][,function3]...}
-\series default
- Generally follow the C99 standard, but allow SDCC features that conflict
- with the standard (incomplete support).
-\end_layout
+\end_inset
-\begin_layout List
-\labelwidthstring 00.00.0000
+function1[,function2][,function3]....
+\series default
+ The compiler by default uses a caller saves convention for register saving
+ across function calls, however this can cause unnecessary register pushing
+ and popping when calling small functions from larger functions.
+ This option can be used to switch the register saving convention for the
+ function names specified.
+ The compiler will not save registers when calling these functions, no extra
+ code will be generated at the entry and exit (function prologue
\series bold
--
-\begin_inset ERT
-status collapsed
-\begin_layout Standard
+\begin_inset LatexCommand \index{function prologue}
+\end_inset
-\backslash
-/
-\end_layout
-\end_inset
+\series default
+ and epilogue
+\series bold
--std-c99
-\begin_inset LatexCommand \index{-\/-std-sdcc99}
+\begin_inset LatexCommand \index{function epilogue}
\end_inset
\series default
- Follow the C99 standard and disable SDCC features that conflict with the
- standard (incomplete support).
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
-
-\series bold
--
+) for these functions to save and restore the registers used by these functions,
+ this can SUBSTANTIALLY reduce code and improve run time performance of
+ the generated code.
+ In the future the compiler (with inter procedural analysis) will be able
+ to determine the appropriate scheme to use for each function call.
+ DO NOT use this option for built-in functions such as _mulint..., if this
+ option is used for a library function the appropriate library function
+ needs to be recompiled with the same option.
+ If the project consists of multiple source files then all the source file
+ should be compiled with the same -
\begin_inset ERT
status collapsed
\end_inset
--codeseg
-\series default
-
-\begin_inset LatexCommand \index{-\/-codeseg <Value>}
+-callee-saves option string.
+ Also see #pragma\InsetSpace ~
+callee_saves
+\begin_inset LatexCommand \index{\#pragma callee\_saves}
\end_inset
-\InsetSpace ~
-<Name> The name to be used for the code
-\begin_inset LatexCommand \index{code}
+
+\begin_inset LatexCommand \vpageref{ite:callee_saves-function1[,function2[,function3...]]--}
\end_inset
- segment, default CSEG.
- This is useful if you need to tell the compiler to put the code in a special
- segment so you can later on tell the linker to put this segment in a special
- place in memory.
- Can be used for instance when using bank switching to put the code in a
- bank.
+.
\end_layout
\begin_layout List
\end_inset
--constseg
+-all-callee-saves
+\begin_inset LatexCommand \index{-\/-all-callee-saves}
+
+\end_inset
+
+
\series default
+Function of
+\series bold
+
+\series default
+-
+\begin_inset ERT
+status collapsed
-\begin_inset LatexCommand \index{-\/-constseg <Value>}
+\begin_layout Standard
-\end_inset
-\InsetSpace ~
-<Name> The name to be used for the const
-\begin_inset LatexCommand \index{code}
+\backslash
+/
+\end_layout
\end_inset
- segment, default CONST.
- This is useful if you need to tell the compiler to put the const data in
- a special segment so you can later on tell the linker to put this segment
- in a special place in memory.
- Can be used for instance when using bank switching to put the const data
- in a bank.
+-callee-saves will be applied to all functions by default.
\end_layout
\begin_layout List
\end_inset
--fdollars-in-identifiers
-\begin_inset LatexCommand \index{-\/-fdollars-in-identifiers}
+-debug
+\begin_inset LatexCommand \index{-\/-debug}
\end_inset
+\bar under
+
\series default
- Permit '$' as an identifier character
+\bar default
+When this option is used the compiler will generate debug information.
+ The debug information collected in a file with .cdb extension can be used
+ with the SDCDB.
+ For more information see documentation for SDCDB.
+ Another file with no extension contains debug information in AOMF or AOMF51
+\begin_inset LatexCommand \index{AOMF, AOMF51}
+
+\end_inset
+
+ format which is commonly used by third party tools.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
-more-pedantic
-\series default
- Actually this is
-\series bold
-\emph on
-not
-\series default
-\emph default
- a SDCC compiler option but if you want
-\emph on
-more
-\emph default
- warnings you can use a separate tool dedicated to syntax checking like
- splint
-\begin_inset LatexCommand \label{lyx:more-pedantic-SPLINT}
+-S
+\begin_inset LatexCommand \index{-S}
\end_inset
-\begin_inset LatexCommand \index{lint (syntax checking tool)}
+\size large
+\bar under
+
+\series default
+\size default
+\bar default
+Stop after the stage of compilation proper; do not assemble.
+ The output is an assembler code file for the input file specified.
+\end_layout
-\end_inset
+\begin_layout List
+\labelwidthstring 00.00.0000
-
-\begin_inset LatexCommand \url{http://www.splint.org}
+\series bold
+-
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-.
- To make your source files parseable by splint you will have to include
-
-\family sans
-lint.h
-\family default
-\begin_inset LatexCommand \index{splint (syntax checking tool)}
+\backslash
+/
+\end_layout
\end_inset
- in your source file and add brackets around extended keywords (like
-\family sans
+-int-long-reent
+\begin_inset LatexCommand \index{-\/-int-long-reent}
-\begin_inset Quotes sld
\end_inset
-__at\InsetSpace ~
-\series bold
-(
\series default
-0xab
+ Integer (16 bit) and long (32 bit) libraries have been compiled as reentrant.
+ Note by default these libraries are compiled as non-reentrant.
+ See section Installation for more details.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+
\series bold
-)
-\series default
+-
+\begin_inset ERT
+status collapsed
-\begin_inset Quotes srd
-\end_inset
+\begin_layout Standard
-\family default
- and
-\family sans
+\backslash
+/
+\end_layout
-\begin_inset Quotes sld
\end_inset
-__interrupt\InsetSpace ~
-(2)
-\begin_inset Quotes srd
+-cyclomatic
+\begin_inset LatexCommand \index{-\/-cyclomatic}
+
\end_inset
-\family default
-).
+\bar under
-\newline
-Splint has an excellent on line manual at
-\begin_inset LatexCommand \url{http://www.splint.org/manual/}
+\series default
+\bar default
+This option will cause the compiler to generate an information message for
+ each function in the source file.
+ The message contains some
+\emph on
+important
+\emph default
+ information about the function.
+ The number of edges and nodes the compiler detected in the control flow
+ graph of the function, and most importantly the
+\emph on
+cyclomatic complexity
+\begin_inset LatexCommand \index{Cyclomatic complexity}
\end_inset
- and it's capabilities go beyond pure syntax checking.
- You'll need to tell splint the location of SDCC's include files so a typical
- command line could look like this:
-\newline
-\family sans
-splint\InsetSpace ~
--I\InsetSpace ~
-/usr/local/share/sdcc/include/mcs51/\InsetSpace ~
-\InsetSpace ~
-myprogram.c
+\emph default
+ see section on Cyclomatic Complexity for more details.
\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
\begin_layout Standard
-\begin_inset VSpace bigskip
-\end_inset
+\backslash
+/
\end_layout
-\begin_layout Subsection
-Intermediate Dump Options
-\begin_inset LatexCommand \label{sub:Intermediate-Dump-Options}
-
\end_inset
-
-\begin_inset LatexCommand \index{Options intermediate dump}
+-float-reent
+\begin_inset LatexCommand \index{-\/-float-reent}
\end_inset
-\begin_inset LatexCommand \index{Intermediate dump options}
+\series default
+ Floating point library is compiled as reentrant
+\begin_inset LatexCommand \index{reentrant}
\end_inset
-
+.
+ See section Installation for more details.
\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
\begin_layout Standard
-The following options are provided for the purpose of retargetting and debugging
- the compiler.
- They provide a means to dump the intermediate code (iCode
-\begin_inset LatexCommand \index{iCode}
-\end_inset
-) generated by the compiler in human readable form at various stages of
- the compilation process.
- More on iCodes see chapter
-\begin_inset LatexCommand \ref{sub:The-anatomy-of}
+\backslash
+/
+\end_layout
\end_inset
-
-\begin_inset Quotes srd
-\end_inset
+-funsigned-char
+\begin_inset LatexCommand \index{-\/-funsigned-char}
-The anatomy of the compiler
-\begin_inset Quotes srd
\end_inset
+
+\series default
+ The default signedness for every type is
+\family typewriter
+ signed
+\family default
+.
+ In some embedded environments the default signedness of
+\family typewriter
+ char
+\family default
+ is
+\family typewriter
+ unsigned
+\family default
.
+ To set the signess for characters to unsigned, use the option -
+\series bold
+
+\begin_inset ERT
+status open
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+
+\series default
+-funsigned-char.
+ If this option is set and no signedness keyword (unsigned/signed) is given,
+ a char will be signed.
+ All other types are unaffected.
\end_layout
\begin_layout List
\end_inset
--dumpraw
-\begin_inset LatexCommand \index{-\/-dumpraw}
+-main-return
+\begin_inset LatexCommand \index{-\/-main-return}
\end_inset
\series default
- This option will cause the compiler to dump the intermediate code into
- a file of named
-\emph on
-<source filename>.dumpraw
-\emph default
- just after the intermediate code has been generated for a function, i.e.
- before any optimizations are done.
- The basic blocks
-\begin_inset LatexCommand \index{Basic blocks}
+ This option can be used if the code generated is called by a monitor program
+ or if the main routine includes an endless loop.
+ This option results in slightly smaller code and saves two bytes of stack
+ space.
+ The return from the 'main'
+\begin_inset LatexCommand \index{main return}
\end_inset
- at this stage ordered in the depth first number, so they may not be in
- sequence of execution.
+ function will return to the function calling main.
+ The default setting is to lock up i.e.
+ generate a '
+\family typewriter
+sjmp .
+\family default
+'.
\end_layout
\begin_layout List
\end_inset
--dumpgcse
-\begin_inset LatexCommand \index{-\/-dumpgcse}
+-nostdinc
+\begin_inset LatexCommand \index{-\/-nostdinc}
\end_inset
\series default
- Will create a dump of iCode's, after global subexpression elimination
-\begin_inset LatexCommand \index{Global subexpression elimination}
-
-\end_inset
-
-, into a file named
-\emph on
-<source filename>.dumpgcse.
+ This will prevent the compiler from passing on the default include path
+ to the preprocessor.
\end_layout
\begin_layout List
\end_inset
--dumpdeadcode
-\begin_inset LatexCommand \index{-\/-dumpdeadcode}
+-nostdlib
+\begin_inset LatexCommand \index{-\/-nostdlib}
\end_inset
\series default
- Will create a dump of iCode's, after deadcode elimination
-\begin_inset LatexCommand \index{Dead-code elimination}
+ This will prevent the compiler from passing on the default library
+\begin_inset LatexCommand \index{Libraries}
\end_inset
-, into a file named
-\emph on
-<source filename>.dumpdeadcode.
+ path to the linker.
\end_layout
\begin_layout List
\end_inset
--dumploop
-\begin_inset LatexCommand \index{-\/-dumploop}
+-verbose
+\begin_inset LatexCommand \index{-\/-verbose}
\end_inset
\series default
-\size large
-
-\size default
-Will create a dump of iCode's, after loop optimizations
-\begin_inset LatexCommand \index{Loop optimization}
+ Shows the various actions the compiler is performing.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-V
+\begin_inset LatexCommand \index{-V}
\end_inset
-, into a file named
-\emph on
-<source filename>.dumploop.
+
+\series default
+ Shows the actual commands the compiler is executing.
\end_layout
\begin_layout List
\end_inset
--dumprange
-\begin_inset LatexCommand \index{-\/-dumprange}
+-no-c-code-in-asm
+\begin_inset LatexCommand \index{-\/-no-c-code-in-asm}
\end_inset
\series default
-\size large
-
-\size default
-Will create a dump of iCode's, after live range analysis
-\begin_inset LatexCommand \index{Live range analysis}
-
-\end_inset
-
-, into a file named
-\emph on
-<source filename>.dumprange.
+ Hides your ugly and inefficient c-code from the asm file, so you can always
+ blame the compiler :)
\end_layout
\begin_layout List
\end_inset
--dumlrange
-\begin_inset LatexCommand \index{-\/-dumlrange}
+-fverbose-asm
+\begin_inset LatexCommand \index{-\/-no-gen-comments}
\end_inset
\series default
- Will dump the life ranges
-\begin_inset LatexCommand \index{Live range analysis}
-
-\end_inset
-
- for all symbols.
+ Include code generator and peep-hole comments in the generated asm files.
\end_layout
\begin_layout List
\end_inset
--dumpregassign
-\begin_inset LatexCommand \index{-\/-dumpregassign}
+-no-peep-comments
+\begin_inset LatexCommand \index{-\/-no-peep-comments}
\end_inset
-\bar under
-
\series default
-\bar default
-Will create a dump of iCode's, after register assignment
-\begin_inset LatexCommand \index{Register assignment}
+ Don't include peep-hole comments in the generated asm files even if -
+\series bold
+
+\begin_inset ERT
+status open
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
\end_inset
-, into a file named
-\emph on
-<source filename>.dumprassgn.
+
+\series default
+-fverbose-asm option is specified.
\end_layout
\begin_layout List
\end_inset
--dumplrange
-\begin_inset LatexCommand \index{-\/-dumplrange}
+-i-code-in-asm
+\begin_inset LatexCommand \index{-\/-i-code-in-asm}
\end_inset
\series default
- Will create a dump of the live ranges of iTemp's
+ Include i-codes in the asm file.
+ Sounds like noise but is most helpful for debugging the compiler itself.
\end_layout
\begin_layout List
\end_inset
--dumpall
-\begin_inset LatexCommand \index{-\/-dumpall}
+-less-pedantic
+\begin_inset LatexCommand \index{pedantic}
\end_inset
-\size large
-\bar under
-
-\series default
-\size default
-\bar default
-Will cause all the above mentioned dumps to be created.
-\end_layout
+\begin_inset LatexCommand \index{-\/-less-pedantic}
-\begin_layout Standard
-\begin_inset VSpace bigskip
\end_inset
-\end_layout
+\series default
-\begin_layout Subsection
-Redirecting output on Windows Shells
-\end_layout
+\begin_inset LatexCommand \label{lyx:--less-pedantic}
-\begin_layout Standard
-By default SDCC writes it's error messages to
-\begin_inset Quotes sld
\end_inset
-standard error
-\begin_inset Quotes srd
+ Disable some of the more pedantic warnings
+\begin_inset LatexCommand \index{Warnings}
+
\end_inset
.
- To force all messages to
-\begin_inset Quotes sld
-\end_inset
+ For more details, see the less_pedantic pragma
+\begin_inset LatexCommand \vpageref{ite:less_pedantic}
-standard output
-\begin_inset Quotes srd
\end_inset
- use
+.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+
\series bold
-
-\series default
-\emph on
-
\begin_inset ERT
status collapsed
\end_inset
-
-\series bold
-\emph default
--
-\series default
-use-stdout
-\begin_inset LatexCommand \index{-\/-use-stdout}
+-disable-warning\InsetSpace ~
+<nnnn>
+\begin_inset LatexCommand \index{-\/-disable-warning}
\end_inset
-.
- Additionally, if you happen to have visual studio installed in your windows
- machine, you can use it to compile your sources using a custom build and
- the SDCC -
-\emph on
+\series default
+ Disable specific warning with number <nnnn>.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
\begin_inset ERT
status collapsed
\end_inset
-
-\emph default
--vc
-\begin_inset LatexCommand \index{-\/-vc}
+-Werror
+\begin_inset LatexCommand \index{-\/-Werror}
\end_inset
- option.
- Something like this should work:
-\newline
-
-\newline
-\series bold
-c:
-\backslash
-sdcc
-\backslash
-bin
-\backslash
-sdcc.exe -
\series default
-\emph on
+ Treat all warnings as errors.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+\series bold
+-
\begin_inset ERT
status collapsed
\end_inset
+-print-search-dirs
+\begin_inset LatexCommand \index{-\/-print-search-dirs}
+
+\end_inset
+
-\series bold
-\emph default
--vc -
\series default
-\emph on
+ Display the directories in the compiler's search path
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+\series bold
+-
\begin_inset ERT
status collapsed
\end_inset
+-vc
+\begin_inset LatexCommand \index{-\/-vc}
-\series bold
-\emph default
--model-large -c $(InputPath)
-\series default
-
-\begin_inset VSpace bigskip
\end_inset
-\end_layout
-
-\begin_layout Section
-Environment variables
-\begin_inset LatexCommand \index{Environment variables}
+\series default
+ Display errors and warnings using MSVC style, so you can use SDCC with
+ the visual studio IDE
+\begin_inset LatexCommand \index{IDE}
\end_inset
+.
+ With SDCC both offering a GCC-like (the default) and a MSVC-like
+\begin_inset LatexCommand \index{MSVC output style}
-\end_layout
+\end_inset
-\begin_layout Standard
-SDCC recognizes the following environment variables:
+ output style, integration into most programming editors should be straightforwa
+rd.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
-SDCC_LEAVE_SIGNALS
-\begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
-
-\end_inset
-
+-
+\begin_inset ERT
+status collapsed
-\series default
- SDCC installs a signal handler
-\begin_inset LatexCommand \index{signal handler}
+\begin_layout Standard
-\end_inset
- to be able to delete temporary files after an user break (^C) or an exception.
- If this environment variable is set, SDCC won't install the signal handler
- in order to be able to debug SDCC.
+\backslash
+/
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\end_inset
-\series bold
-TMP,\InsetSpace ~
-TEMP,\InsetSpace ~
-TMPDIR
-\begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}
+-use-stdout
+\begin_inset LatexCommand \index{-\/-use-stdout}
\end_inset
\series default
- Path, where temporary files will be created.
- The order of the variables is the search order.
- In a standard *nix environment these variables are not set, and there's
- no need to set them.
- On Windows it's recommended to set one of them.
+ Send errors and warnings to stdout instead of stderr.
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
-SDCC_HOME
-\begin_inset LatexCommand \index{SDCC\_HOME}
+-Wa\InsetSpace ~
+asmOption[,asmOption]
+\series default
-\end_inset
+\begin_inset LatexCommand \index{-Wa asmOption[,asmOption]}
+\end_inset
-\series default
- Path, see section
-\begin_inset LatexCommand \ref{sub:Install-paths}
+...
+ Pass the asmOption to the assembler
+\begin_inset LatexCommand \index{Options assembler}
\end_inset
-\InsetSpace ~
-\begin_inset Quotes sld
-\end_inset
+\begin_inset LatexCommand \index{Assembler options}
- Install Paths
-\begin_inset Quotes srd
\end_inset
.
+ See file sdcc/as/doc/asxhtm.html for assembler options.cd
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
-SDCC_INCLUDE
-\begin_inset LatexCommand \index{SDCC\_INCLUDE}
-
-\end_inset
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
-\series default
- Path, see section
-\begin_inset LatexCommand \ref{sub:Search-Paths}
+\backslash
+/
+\end_layout
\end_inset
-\InsetSpace ~
+-std-sdcc89
+\begin_inset LatexCommand \index{-\/-std-sdcc89}
-\begin_inset Quotes sld
\end_inset
-Search Paths
-\begin_inset Quotes srd
-\end_inset
-.
+\series default
+ Generally follow the C89 standard, but allow SDCC features that conflict
+ with the standard (default).
\end_layout
\begin_layout List
\labelwidthstring 00.00.0000
\series bold
-SDCC_LIB
-\begin_inset LatexCommand \index{SDCC\_LIB}
+-
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-\series default
- Path, see section
-\begin_inset LatexCommand \ref{sub:Search-Paths}
+\backslash
+/
+\end_layout
\end_inset
-\InsetSpace ~
+-std-c89
+\begin_inset LatexCommand \index{-\/-std-c89}
-\begin_inset Quotes sld
\end_inset
-Search Paths
-\begin_inset Quotes srd
-\end_inset
-..
+\series default
+ Follow the C89 standard and disable SDCC features that conflict with the
+ standard.
\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
\begin_layout Standard
-There are some more environment variables recognized by SDCC, but these
- are solely used for debugging purposes.
- They can change or disappear very quickly, and will never be documented.
-\begin_inset VSpace bigskip
-\end_inset
+\backslash
+/
\end_layout
-\begin_layout Section
-Storage Class Language Extensions
-\end_layout
+\end_inset
-\begin_layout Subsection
-MCS51/DS390 Storage Class
-\begin_inset LatexCommand \index{Storage class}
+-std-sdcc99
+\begin_inset LatexCommand \index{-\/-std-sdcc99}
\end_inset
- Language Extensions
-\end_layout
-\begin_layout Standard
-In addition to the ANSI storage classes SDCC allows the following MCS51
- specific storage classes:
+\series default
+ Generally follow the C99 standard, but allow SDCC features that conflict
+ with the standard (incomplete support).
\end_layout
-\begin_layout Subsubsection
-data
-\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
-
-\end_inset
+\begin_layout List
+\labelwidthstring 00.00.0000
+\series bold
+-
+\begin_inset ERT
+status collapsed
-\begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
+\begin_layout Standard
-\end_inset
- / near
-\begin_inset LatexCommand \index{near (storage class)}
+\backslash
+/
+\end_layout
\end_inset
-
-\begin_inset LatexCommand \index{\_\_near (storage class)}
+-std-c99
+\begin_inset LatexCommand \index{-\/-std-sdcc99}
\end_inset
-\end_layout
-
-\begin_layout Standard
-This is the
-\series bold
-default
\series default
- storage class for the Small Memory model (
-\emph on
-data
-\emph default
- and
-\emph on
-near
-\emph default
- or the more ANSI-C compliant forms
-\emph on
-__data
-\emph default
- and
-\emph on
-__near
-\emph default
- can be used synonymously).
- Variables declared with this storage class will be allocated in the directly
- addressable portion of the internal RAM of a 8051, e.g.:
+ Follow the C99 standard and disable SDCC features that conflict with the
+ standard (incomplete support).
\end_layout
-\begin_layout Verse
+\begin_layout List
+\labelwidthstring 00.00.0000
-\family typewriter
-__data unsigned char test_data;
-\end_layout
+\series bold
+-
+\begin_inset ERT
+status collapsed
\begin_layout Standard
-Writing 0x01 to this variable generates the assembly code:
-\end_layout
-\begin_layout Verse
-\family typewriter
-75*00 01\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov\InsetSpace ~
-\InsetSpace ~
-_test_data,#0x01
+\backslash
+/
\end_layout
-\begin_layout Subsubsection
-xdata
-\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
-
\end_inset
+-codeseg
+\series default
-\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
-
-\end_inset
-
- / far
-\begin_inset LatexCommand \index{far (storage class)}
+\begin_inset LatexCommand \index{-\/-codeseg <Value>}
\end_inset
-\begin_inset LatexCommand \index{\_\_far (storage class)}
+\begin_inset LatexCommand \label{lyx:-codeseg}
\end_inset
+\InsetSpace ~
+<Name> The name to be used for the code
+\begin_inset LatexCommand \index{code}
-\end_layout
+\end_inset
-\begin_layout Standard
-Variables declared with this storage class will be placed in the external
- RAM.
- This is the
-\series bold
-default
-\series default
- storage class for the Large Memory model, e.g.:
+ segment, default CSEG.
+ This is useful if you need to tell the compiler to put the code in a special
+ segment so you can later on tell the linker to put this segment in a special
+ place in memory.
+ Can be used for instance when using bank switching to put the code in a
+ bank.
\end_layout
-\begin_layout Verse
+\begin_layout List
+\labelwidthstring 00.00.0000
-\family typewriter
-__xdata unsigned char test_xdata;
-\end_layout
+\series bold
+-
+\begin_inset ERT
+status collapsed
\begin_layout Standard
-Writing 0x01 to this variable generates the assembly code:
-\end_layout
-\begin_layout Verse
-\family typewriter
-90s00r00\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov\InsetSpace ~
-\InsetSpace ~
-dptr,#_test_xdata
-\newline
-74\InsetSpace ~
-01\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov\InsetSpace ~
-\InsetSpace ~
-a,#0x01
-\newline
-F0\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-movx\InsetSpace ~
-@dptr,a
+\backslash
+/
\end_layout
-\begin_layout Subsubsection
-idata
-\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
-
\end_inset
+-constseg
+\series default
-\begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
+\begin_inset LatexCommand \index{-\/-constseg <Value>}
\end_inset
+\InsetSpace ~
+<Name> The name to be used for the const
+\begin_inset LatexCommand \index{const}
+
+\end_inset
+ segment, default CONST.
+ This is useful if you need to tell the compiler to put the const data in
+ a special segment so you can later on tell the linker to put this segment
+ in a special place in memory.
+ Can be used for instance when using bank switching to put the const data
+ in a bank.
\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
\begin_layout Standard
-Variables declared with this storage class will be allocated into the indirectly
- addressable portion of the internal ram of a 8051, e.g.:
+
+
+\backslash
+/
\end_layout
-\begin_layout Verse
+\end_inset
-\family typewriter
-__idata unsigned char test_idata;
+-fdollars-in-identifiers
+\begin_inset LatexCommand \index{-\/-fdollars-in-identifiers}
+
+\end_inset
+
+
+\series default
+ Permit '$' as an identifier character.
\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
\begin_layout Standard
-Writing 0x01 to this variable generates the assembly code:
-\end_layout
-\begin_layout Verse
-\family typewriter
-78r00\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov\InsetSpace ~
-\InsetSpace ~
-r0,#_test_idata
-\newline
-76\InsetSpace ~
-01\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov\InsetSpace ~
-\InsetSpace ~
-@r0,#0x01
+\backslash
+/
\end_layout
-\begin_layout Standard
-Please note, the first 128 byte of idata physically access the same RAM
- as the data memory.
- The original 8051 had 128 byte idata memory, nowadays most devices have
- 256 byte idata memory.
- The stack
-\begin_inset LatexCommand \index{stack}
+\end_inset
+
+-more-pedantic
+\series default
+
+\begin_inset LatexCommand \index{-\/-more-pedantic}
\end_inset
- is located in idata memory.
-\end_layout
-\begin_layout Subsubsection
-pdata
-\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
+\begin_inset LatexCommand \index{pedantic}
+
+\end_inset
+
+ Actually this is
+\series bold
+\emph on
+not
+\series default
+\emph default
+ a SDCC compiler option but if you want
+\emph on
+more
+\emph default
+ warnings you can use a separate tool dedicated to syntax checking like
+ splint
+\begin_inset LatexCommand \label{lyx:more-pedantic-SPLINT}
\end_inset
-\begin_inset LatexCommand \index{\_\_pdata (mcs51, ds390 storage class)}
+\begin_inset LatexCommand \index{lint (syntax checking tool)}
\end_inset
+
+\begin_inset LatexCommand \url{http://www.splint.org}
-\end_layout
+\end_inset
-\begin_layout Standard
-Paged xdata access is just as straightforward as using the other addressing
- modes of a 8051.
- It is typically located at the start of xdata and has a maximum size of
- 256 bytes.
- The following example writes 0x01 to the pdata variable.
- Please note, pdata access physically accesses xdata memory.
- The high byte of the address is determined by port P2
-\begin_inset LatexCommand \index{P2 (mcs51 sfr)}
+.
+ To make your source files parseable by splint you will have to include
+
+\family sans
+lint.h
+\family default
+
+\begin_inset LatexCommand \index{splint (syntax checking tool)}
\end_inset
-(or in case of some 8051 variants by a separate Special Function Register,
- see section
-\begin_inset LatexCommand \ref{sub:MCS51-variants}
+ in your source file and add brackets around extended keywords (like
+\family sans
+\begin_inset Quotes sld
\end_inset
-).
- This is the
+__at\InsetSpace ~
+
\series bold
-default
+(
+\series default
+0xab
+\series bold
+)
\series default
- storage class for the Medium Memory model, e.g.:
-\end_layout
-\begin_layout Verse
+\begin_inset Quotes srd
+\end_inset
-\family typewriter
-__pdata unsigned char test_pdata;
-\end_layout
-\begin_layout Standard
-Writing 0x01 to this variable generates the assembly code:
-\end_layout
+\family default
+ and
+\family sans
-\begin_layout Verse
+\begin_inset Quotes sld
+\end_inset
-\family typewriter
-78r00\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov r0,#_test_pdata
+__interrupt\InsetSpace ~
+(2)
+\begin_inset Quotes srd
+\end_inset
+
+
+\family default
+).
+
\newline
-74 01\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov a,#0x01
+Splint has an excellent on line manual at
+\begin_inset LatexCommand \url{http://www.splint.org/manual/}
+
+\end_inset
+
+ and it's capabilities go beyond pure syntax checking.
+ You'll need to tell splint the location of SDCC's include files so a typical
+ command line could look like this:
\newline
-F2\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
+
+\family sans
+splint\InsetSpace ~
+-I\InsetSpace ~
+/usr/local/share/sdcc/include/mcs51/\InsetSpace ~
\InsetSpace ~
-movx @r0,a
+myprogram.c
\end_layout
-\begin_layout Standard
-If the -
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
\begin_inset ERT
status collapsed
\end_inset
--xstack
-\begin_inset LatexCommand \index{-\/-xstack}
+-short-is-8bits
+\series default
+
+\begin_inset LatexCommand \index{-\/-short-is-8bits}
\end_inset
- option is used the pdata memory area is followed by the xstack memory area
- and the sum of their sizes is limited to 256 bytes.
-\end_layout
-\begin_layout Subsubsection
-code
-\begin_inset LatexCommand \index{code}
+\begin_inset LatexCommand \label{lyx:--short-is-8bits}
\end_inset
-
-\begin_inset LatexCommand \index{\_\_code}
+ Treat short as 8-bit (for backward compatibility with older versions of
+ compiler - see section
+\begin_inset LatexCommand \ref{sec:Compatibility-with-previous}
\end_inset
-
+)
\end_layout
\begin_layout Standard
-'Variables' declared with this storage class will be placed in the code
- memory:
-\end_layout
+\begin_inset VSpace bigskip
+\end_inset
-\begin_layout Verse
-\family typewriter
-__code unsigned char test_code;
\end_layout
-\begin_layout Standard
-Read access to this variable generates the assembly code:
-\end_layout
+\begin_layout Subsection
+Intermediate Dump Options
+\begin_inset LatexCommand \label{sub:Intermediate-Dump-Options}
-\begin_layout Verse
+\end_inset
-\family typewriter
-90s00r6F\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov dptr,#_test_code
-\newline
-E4\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-clr a
-\newline
-93\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-movc a,@a+dptr
-\end_layout
-\begin_layout Standard
+\begin_inset LatexCommand \index{Options intermediate dump}
-\family typewriter
-char
-\family default
- indexed arrays of characters in code memory can be accessed efficiently:
-\end_layout
+\end_inset
+
+
+\begin_inset LatexCommand \index{Intermediate dump options}
+
+\end_inset
-\begin_layout Verse
-\family typewriter
-__code char test_array[] = {'c','h','e','a','p'};
\end_layout
\begin_layout Standard
-Read access to this array using an 8-bit unsigned index generates the assembly
- code:
-\end_layout
+The following options are provided for the purpose of retargetting and debugging
+ the compiler.
+ They provide a means to dump the intermediate code (iCode
+\begin_inset LatexCommand \index{iCode}
-\begin_layout Verse
+\end_inset
-\family typewriter
-E5*00\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov a,_index
-\end_layout
+) generated by the compiler in human readable form at various stages of
+ the compilation process.
+ More on iCodes see chapter
+\begin_inset LatexCommand \ref{sub:The-anatomy-of}
-\begin_layout Verse
+\end_inset
-\family typewriter
-90s00r41\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-mov dptr,#_test_array
-\end_layout
+
+\begin_inset Quotes srd
+\end_inset
-\begin_layout Verse
+The anatomy of the compiler
+\begin_inset Quotes srd
+\end_inset
-\family typewriter
-93\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-movc a,@a+dptr
+.
\end_layout
-\begin_layout Subsubsection
-bit
-\begin_inset LatexCommand \index{bit}
+\begin_layout List
+\labelwidthstring 00.00.0000
-\end_inset
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
-\begin_inset LatexCommand \index{\_\_bit}
+\backslash
+/
+\end_layout
\end_inset
+-dumpraw
+\begin_inset LatexCommand \index{-\/-dumpraw}
-\end_layout
+\end_inset
-\begin_layout Standard
-This is a data-type and a storage class specifier.
- When a variable is declared as a bit, it is allocated into the bit addressable
- memory of 8051, e.g.:
-\end_layout
-\begin_layout Verse
+\series default
+ This option will cause the compiler to dump the intermediate code into
+ a file of named
+\emph on
+<source filename>.dumpraw
+\emph default
+ just after the intermediate code has been generated for a function, i.e.
+ before any optimizations are done.
+ The basic blocks
+\begin_inset LatexCommand \index{Basic blocks}
-\family typewriter
-__bit test_bit;
-\end_layout
+\end_inset
-\begin_layout Standard
-Writing 1 to this variable generates the assembly code:
+ at this stage ordered in the depth first number, so they may not be in
+ sequence of execution.
\end_layout
-\begin_layout Verse
+\begin_layout List
+\labelwidthstring 00.00.0000
-\family typewriter
-D2*00\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-setb\InsetSpace ~
-_test_bit
-\end_layout
+\series bold
+-
+\begin_inset ERT
+status collapsed
\begin_layout Standard
-The bit addressable memory consists of 128 bits which are located from 0x20
- to 0x2f in data memory.
-
-\newline
-Apart from this 8051 specific storage class most architectures support
- ANSI-C bitfields
-\begin_inset LatexCommand \index{bitfields}
+
+
+\backslash
+/
+\end_layout
\end_inset
+-dumpgcse
+\begin_inset LatexCommand \index{-\/-dumpgcse}
-\begin_inset Foot
-status open
+\end_inset
-\begin_layout Standard
-Not really meant as examples, but nevertheless showing what bitfields are
- about: device/include/mc68hc908qy.h and support/regression/tests/bitfields.c
-\end_layout
+
+\series default
+ Will create a dump of iCodes, after global subexpression elimination
+\begin_inset LatexCommand \index{Global subexpression elimination}
\end_inset
-.
- In accordance with ISO/IEC 9899 bits and bitfields without an explicit
- signed modifier are implemented as unsigned.
+, into a file named
+\emph on
+<source filename>.dumpgcse.
\end_layout
-\begin_layout Subsubsection
-sfr
-\begin_inset LatexCommand \index{sfr}
+\begin_layout List
+\labelwidthstring 00.00.0000
-\end_inset
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
-\begin_inset LatexCommand \index{\_\_sfr}
+\backslash
+/
+\end_layout
\end_inset
- / sfr16
-\begin_inset LatexCommand \index{sfr16}
+-dumpdeadcode
+\begin_inset LatexCommand \index{-\/-dumpdeadcode}
\end_inset
-\begin_inset LatexCommand \index{\_\_sfr16}
+\series default
+ Will create a dump of iCodes, after deadcode elimination
+\begin_inset LatexCommand \index{Dead-code elimination}
\end_inset
- / sfr32
-\begin_inset LatexCommand \index{sfr32}
+, into a file named
+\emph on
+<source filename>.dumpdeadcode.
+\end_layout
-\end_inset
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
+status collapsed
+\begin_layout Standard
-\begin_inset LatexCommand \index{\_\_sfr32}
+
+\backslash
+/
+\end_layout
\end_inset
- / sbit
-\begin_inset LatexCommand \index{\_\_sbit}
+-dumploop
+\begin_inset LatexCommand \index{-\/-dumploop}
\end_inset
-\begin_inset LatexCommand \index{sbit}
+\series default
+\size large
+
+\size default
+Will create a dump of iCodes, after loop optimizations
+\begin_inset LatexCommand \index{Loop optimization}
\end_inset
-
+, into a file named
+\emph on
+<source filename>.dumploop.
\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
\begin_layout Standard
-Like the bit keyword,
-\emph on
-sfr / sfr16 / sfr32 / sbit
-\emph default
-signify both a data-type and storage class, they are used to describe the
-
-\emph on
-s
-\emph default
-pecial
-\emph on
-f
-\emph default
-unction
-\emph on
-r
-\emph default
-egisters and
-\emph on
-s
-\emph default
-pecial
-\emph on
-bit
-\emph default
- variables of a 8051, eg:
+
+
+\backslash
+/
\end_layout
-\begin_layout Verse
+\end_inset
-\family typewriter
-__sfr __at
-\begin_inset LatexCommand \index{at}
+-dumprange
+\begin_inset LatexCommand \index{-\/-dumprange}
\end_inset
-\begin_inset LatexCommand \index{\_\_at}
+\series default
+\size large
+
+\size default
+Will create a dump of iCodes, after live range analysis
+\begin_inset LatexCommand \index{Live range analysis}
\end_inset
- (0x80) P0;\InsetSpace ~
- /* special function register P0 at location 0x80 */
-\newline
+, into a file named
+\emph on
+<source filename>.dumprange.
+\end_layout
-\newline
-/* 16 bit
- special function register combination for timer 0
-\newline
-\InsetSpace ~
-\InsetSpace ~
- with the high byte at
- location 0x8C and the low byte at location 0x8A */
-\newline
-__sfr16 __at (0x8C8A)
- TMR0;
-\newline
+\begin_layout List
+\labelwidthstring 00.00.0000
-\newline
-__sbit __at
-\begin_inset LatexCommand \index{at}
+\series bold
+-
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-\begin_inset LatexCommand \index{\_\_at}
+\backslash
+/
+\end_layout
\end_inset
- (0xd7) CY;\InsetSpace ~
- /* CY (Carry Flag
-\begin_inset LatexCommand \index{Flags}
+-dumlrange
+\begin_inset LatexCommand \index{-\/-dumlrange}
\end_inset
-\begin_inset LatexCommand \index{Carry flag}
+\series default
+ Will dump the life ranges
+\begin_inset LatexCommand \index{Live range analysis}
\end_inset
-) */
+ for all symbols.
\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
+status collapsed
+
\begin_layout Standard
-Special function registers which are located on an address dividable by
- 8 are bit-addressable, an
-\emph on
- sbit
-\emph default
- addresses a specific bit within these sfr.
-\newline
-16 Bit and 32 bit special function
- register combinations which require a certain access order are better not
- declared using
-\emph on
-sfr16
-\emph default
- or
-\emph on
-sfr32.
-\emph default
- Allthough SDCC usually accesses them Least Significant Byte (LSB) first,
- this is not guaranteed.
-\newline
+\backslash
+/
\end_layout
-\begin_layout Standard
-Please note, if you use a header file which was written for another compiler
- then the sfr / sfr16 / sfr32 / sbit Storage Class extensions will most
- likely be
-\emph on
-not
-\emph default
-compatible.
- Specifically the syntax
-\family typewriter
-\InsetSpace ~
-sfr P0 = 0x80;\InsetSpace ~
+\end_inset
-\family default
- is compiled
+-dumpregassign
+\begin_inset LatexCommand \index{-\/-dumpregassign}
+
+\end_inset
+
+
+\bar under
+
+\series default
+\bar default
+Will create a dump of iCodes, after register assignment
+\begin_inset LatexCommand \index{Register assignment}
+
+\end_inset
+
+, into a file named
\emph on
-without warning
-\emph default
- by SDCC to an assignment of 0x80 to a variable called P0
-\family typewriter
+<source filename>.dumprassgn.
+\end_layout
-\begin_inset Marginal
+\begin_layout List
+\labelwidthstring 00.00.0000
+
+\series bold
+-
+\begin_inset ERT
status collapsed
\begin_layout Standard
-\series bold
-\InsetSpace ~
-!
+
+\backslash
+/
\end_layout
\end_inset
-.
-
-\family default
-Nevertheless it is possible to write header files
-\begin_inset LatexCommand \index{Header files}
+-dumplrange
+\begin_inset LatexCommand \index{-\/-dumplrange}
\end_inset
-\begin_inset LatexCommand \index{Include files}
+\series default
+ Will create a dump of the live ranges of iTemp's
+\end_layout
-\end_inset
+\begin_layout List
+\labelwidthstring 00.00.0000
- which can be shared among different compilers (see section
-\begin_inset LatexCommand \ref{sec:Porting-code-to-other-compilers}
+\series bold
+-
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-).
-
+
+\backslash
+/
\end_layout
-\begin_layout Subsubsection
-Pointers
-\begin_inset LatexCommand \index{Pointer}
+\end_inset
+
+-dumpall
+\begin_inset LatexCommand \index{-\/-dumpall}
\end_inset
- to MCS51/DS390 specific memory spaces
+
+\size large
+\bar under
+
+\series default
+\size default
+\bar default
+Will cause all the above mentioned dumps to be created.
\end_layout
\begin_layout Standard
-SDCC allows (via language extensions) pointers to explicitly point to any
- of the memory spaces
-\begin_inset LatexCommand \index{Memory model}
-
+\begin_inset VSpace bigskip
\end_inset
- of the 8051.
- In addition to the explicit pointers, the compiler uses (by default) generic
- pointers which can be used to point to any of the memory spaces.
-\newline
-\newline
-Pointer
- declaration examples:
\end_layout
-\begin_layout Verse
+\begin_layout Subsection
+Redirecting output on Windows Shells
+\end_layout
-\family typewriter
-/* pointer physically in internal ram pointing to object in external ram
- */
-\newline
-__xdata unsigned char * __data p;
-\newline
+\begin_layout Standard
+By default SDCC writes its error messages to
+\begin_inset Quotes sld
+\end_inset
-\newline
-/* pointer physically in external ram
- pointing to object in internal ram */
-\newline
-__data unsigned char * __xdata p;
-\newline
+standard error
+\begin_inset Quotes srd
+\end_inset
-\newline
-/*
- pointer physically in code rom pointing to data in xdata space */
-\newline
-__xdata
- unsigned char * __code p;
-\newline
+.
+ To force all messages to
+\begin_inset Quotes sld
+\end_inset
-\newline
-/* pointer physically in code space pointing to
- data in code space */
-\newline
-__code unsigned char * __code p;
-\newline
+standard output
+\begin_inset Quotes srd
+\end_inset
-\newline
-/* generic pointer
- physically located in xdata space */
-\newline
-unsigned char * __xdata p;
-\newline
+ use
+\series bold
+-
+\series default
+\emph on
-\newline
-/* generic
- pointer physically located in default memory space */
-\newline
-unsigned char * p;
-\newline
+\begin_inset ERT
+status collapsed
-\newline
-/*
- the following is a function pointer
-\begin_inset LatexCommand \index{function pointer}
+\begin_layout Standard
-\end_inset
- physically located in data space */
-\newline
-char (* __data fp)(void);
+\backslash
+/
\end_layout
-\begin_layout Standard
-Well you get the idea.
-
-\newline
-
-\newline
-All unqualified pointers are treated as 3-byte (4-byte for the ds390)
-\emph on
-generic
-\emph default
- pointers.
-
-\size small
-
-\newline
+\end_inset
-\newline
-\size default
-The highest order byte of the
-\emph on
-generic
-\emph default
- pointers contains the data space information.
- Assembler support routines are called whenever data is stored or retrieved
- using
-\emph on
-generic
+\series bold
\emph default
- pointers.
- These are useful for developing reusable library
-\begin_inset LatexCommand \index{Libraries}
+-
+\series default
+use-stdout
+\begin_inset LatexCommand \index{-\/-use-stdout}
\end_inset
- routines.
- Explicitly specifying the pointer
-\begin_inset LatexCommand \index{pointer}
-
-\end_inset
+.
+ Additionally, if you happen to have visual studio installed in your windows
+ machine, you can use it to compile your sources using a custom build and
+ the SDCC -
+\emph on
- type will generate the most efficient code.
-\end_layout
+\begin_inset ERT
+status collapsed
-\begin_layout Subsubsection
-Notes on MCS51 memory
-\begin_inset LatexCommand \index{MCS51 memory}
+\begin_layout Standard
-\end_inset
- layout
+\backslash
+/
\end_layout
-\begin_layout Standard
-The 8051 family of microcontrollers have a minimum of 128 bytes of internal
- RAM memory which is structured as follows:
-\newline
-
-\newline
-- Bytes 00-1F - 32 bytes to hold
- up to 4 banks of the registers R0 to R7,
-\newline
-- Bytes 20-2F - 16 bytes to hold
- 128 bit
-\begin_inset LatexCommand \index{bit}
-
\end_inset
- variables and,
-\newline
-- Bytes 30-7F - 80 bytes for general purpose use.
-\newline
-
-\end_layout
-\begin_layout Standard
-Additionally some members of the MCS51 family may have up to 128 bytes of
- additional, indirectly addressable, internal RAM memory (
-\emph on
-idata
\emph default
-
-\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
+-vc
+\begin_inset LatexCommand \index{-\/-vc}
\end_inset
+ option.
+ Something like this should work:
+\newline
-\begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
-
-\end_inset
+\newline
-).
- Furthermore, some chips may have some built in external memory (
+\series bold
+c:
+\backslash
+sdcc
+\backslash
+bin
+\backslash
+sdcc.exe -
+\series default
\emph on
-xdata
-\emph default
-\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
+\backslash
+/
+\end_layout
\end_inset
-) which should not be confused with the internal, directly addressable RAM
- memory (
-\emph on
-data
+
+\series bold
\emph default
+-vc -
+\series default
+\emph on
-\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-\begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
+\backslash
+/
+\end_layout
\end_inset
-).
- Sometimes this built in
-\emph on
-xdata
+
+\series bold
\emph default
- memory has to be activated before using it (you can probably find this
- information on the datasheet of the microcontroller your are using, see
- also section
-\begin_inset LatexCommand \ref{sub:Startup-Code}
+-model-large -c $(InputPath)
+\series default
+\begin_inset VSpace bigskip
\end_inset
-\InsetSpace ~
-Startup-Code).
+
\end_layout
-\begin_layout Standard
-Normally SDCC will only use the first bank
-\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
+\begin_layout Section
+Environment variables
+\begin_inset LatexCommand \index{Environment variables}
\end_inset
- of registers (register bank 0), but it is possible to specify that other
- banks of registers (keyword
-\emph on
-using
-\emph default
-
-\emph on
-\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
+\end_layout
-\end_inset
+\begin_layout Standard
+SDCC recognizes the following environment variables:
+\end_layout
+\begin_layout List
+\labelwidthstring 00.00.0000
-\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
+\series bold
+SDCC_LEAVE_SIGNALS
+\begin_inset LatexCommand \index{SDCC\_LEAVE\_SIGNALS}
\end_inset
-\emph default
-) should be used in interrupt
-\begin_inset LatexCommand \index{interrupt}
+\series default
+ SDCC installs a signal handler
+\begin_inset LatexCommand \index{signal handler}
\end_inset
+ to be able to delete temporary files after an user break (^C) or an exception.
+ If this environment variable is set, SDCC won't install the signal handler
+ in order to be able to debug SDCC.
+\end_layout
-\begin_inset LatexCommand \index{\_\_interrupt}
-
-\end_inset
+\begin_layout List
+\labelwidthstring 00.00.0000
- routines.
- By default, the compiler will place the stack after the last byte of allocated
- memory for variables.
- For example, if the first 2 banks of registers are used, and only four
- bytes are used for
-\emph on
-data
-\emph default
- variables, it will position the base of the internal stack at address 20
- (0x14).
- This implies that as the stack
-\begin_inset LatexCommand \index{stack}
+\series bold
+TMP,\InsetSpace ~
+TEMP,\InsetSpace ~
+TMPDIR
+\begin_inset LatexCommand \index{TMP, TEMP, TMPDIR}
\end_inset
- grows, it will use up the remaining register banks, and the 16 bytes used
- by the 128 bit variables, and 80 bytes for general purpose use.
- If any bit variables are used, the data variables will be placed in unused
- register banks and after the byte holding the last bit variable.
- For example, if register banks 0 and 1 are used, and there are 9 bit variables
- (two bytes used),
-\emph on
-data
-\emph default
- variables will be placed starting from address 0x10 to 0x20 and continue
- at address 0x22.
- You can also use -
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-\backslash
-/
+\series default
+ Path, where temporary files will be created.
+ The order of the variables is the search order.
+ In a standard *nix environment these variables are not set, and there's
+ no need to set them.
+ On Windows it's recommended to set one of them.
\end_layout
-\end_inset
+\begin_layout List
+\labelwidthstring 00.00.0000
--data-loc
-\begin_inset LatexCommand \index{-\/-data-loc <Value>}
+\series bold
+SDCC_HOME
+\begin_inset LatexCommand \index{SDCC\_HOME}
\end_inset
- to specify the start address of the
-\emph on
-data
-\emph default
- and -
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-\backslash
-/
-\end_layout
+\series default
+ Path, see section
+\begin_inset LatexCommand \ref{sub:Install-paths}
\end_inset
--iram-size
-\begin_inset LatexCommand \index{-\/-iram-size <Value>}
+\InsetSpace ~
+\begin_inset Quotes sld
\end_inset
- to specify the size of the total internal RAM (
-\emph on
-data
-\emph default
-+
-\emph on
-idata
-\emph default
-).
-
-\newline
+ Install Paths
+\begin_inset Quotes srd
+\end_inset
+.
\end_layout
-\begin_layout Standard
-By default the 8051 linker will place the stack after the last byte of (i)data
- variables.
- Option -
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
+\begin_layout List
+\labelwidthstring 00.00.0000
-\backslash
-/
-\end_layout
+\series bold
+SDCC_INCLUDE
+\begin_inset LatexCommand \index{SDCC\_INCLUDE}
\end_inset
--stack-loc
-\begin_inset LatexCommand \index{-\/-stack-loc <Value>}
+
+\series default
+ Path, see section
+\begin_inset LatexCommand \ref{sub:Search-Paths}
\end_inset
- allows you to specify the start of the stack, i.e.
- you could start it after any data in the general purpose area.
- If your microcontroller has additional indirectly addressable internal
- RAM (
-\emph on
-idata
-\emph default
-) you can place the stack on it.
- You may also need to use -
-\begin_inset ERT
-status collapsed
+\InsetSpace ~
-\begin_layout Standard
+\begin_inset Quotes sld
+\end_inset
+Search Paths
+\begin_inset Quotes srd
+\end_inset
-\backslash
-/
+.
\end_layout
-\end_inset
+\begin_layout List
+\labelwidthstring 00.00.0000
--xdata-loc
-\begin_inset LatexCommand \index{-\/-xdata-loc<Value>}
+\series bold
+SDCC_LIB
+\begin_inset LatexCommand \index{SDCC\_LIB}
\end_inset
- to set the start address of the external RAM (
-\emph on
-xdata
-\emph default
-) and -
-\begin_inset ERT
-status collapsed
-\begin_layout Standard
+\series default
+ Path, see section
+\begin_inset LatexCommand \ref{sub:Search-Paths}
+\end_inset
-\backslash
-/
-\end_layout
+\InsetSpace ~
+\begin_inset Quotes sld
\end_inset
--xram-size
-\begin_inset LatexCommand \index{-\/-xram-size <Value>}
-
+Search Paths
+\begin_inset Quotes srd
\end_inset
- to specify its size.
- Same goes for the code memory, using -
-\begin_inset ERT
-status collapsed
+..
+\end_layout
\begin_layout Standard
+There are some more environment variables recognized by SDCC, but these
+ are solely used for debugging purposes.
+ They can change or disappear very quickly, and will never be documented.
+\begin_inset VSpace bigskip
+\end_inset
-\backslash
-/
\end_layout
-\end_inset
+\begin_layout Section
+Storage Class Language Extensions
+\end_layout
--code-loc
-\begin_inset LatexCommand \index{-\/-code-loc <Value>}
+\begin_layout Subsection
+MCS51/DS390 Storage Class
+\begin_inset LatexCommand \index{Storage class}
\end_inset
- and -
-\begin_inset ERT
-status collapsed
+ Language Extensions
+\end_layout
\begin_layout Standard
-
-
-\backslash
-/
+In addition to the ANSI storage classes SDCC allows the following MCS51
+ specific storage classes:
\end_layout
-\end_inset
-
--code-size
-\begin_inset LatexCommand \index{-\/-code-size <Value>}
+\begin_layout Subsubsection
+data
+\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
\end_inset
-.
- If in doubt, don't specify any options and see if the resulting memory
- layout is appropriate, then you can adjust it.
-\end_layout
-\begin_layout Standard
-The linker generates two files with memory allocation information.
- The first, with extension .map
-\begin_inset LatexCommand \index{<file>.map}
+\begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
\end_inset
- shows all the variables and segments.
- The second with extension .mem
-\begin_inset LatexCommand \index{<file>.mem}
+ / near
+\begin_inset LatexCommand \index{near (storage class)}
\end_inset
- shows the final memory layout.
- The linker will complain either if memory segments overlap, there is not
- enough memory, or there is not enough space for stack.
- If you get any linking warnings and/or errors related to stack or segments
- allocation, take a look at either the .map or .mem files to find out what
- the problem is.
- The .mem file may even suggest a solution to the problem.
-\begin_inset VSpace bigskip
+
+\begin_inset LatexCommand \index{\_\_near (storage class)}
+
\end_inset
\end_layout
-\begin_layout Subsection
-Z80/Z180 Storage Class
-\begin_inset LatexCommand \index{Z80!Storage class}
+\begin_layout Standard
+This is the
+\series bold
+default
+\series default
+ storage class for the Small Memory model (
+\emph on
+data
+\emph default
+ and
+\emph on
+near
+\emph default
+ or the more ANSI-C compliant forms
+\emph on
+__data
+\emph default
+ and
+\emph on
+__near
+\emph default
+ can be used synonymously).
+ Variables declared with this storage class will be allocated in the directly
+ addressable portion of the internal RAM of a 8051, e.g.:
+\end_layout
-\end_inset
+\begin_layout Verse
- Language Extensions
+\family typewriter
+__data unsigned char test_data;
\end_layout
-\begin_layout Subsubsection
-sfr
-\begin_inset LatexCommand \index{sfr}
+\begin_layout Standard
+Writing 0x01 to this variable generates the assembly code:
+\end_layout
-\end_inset
+\begin_layout Verse
+\family typewriter
+75*00 01\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov\InsetSpace ~
+\InsetSpace ~
+_test_data,#0x01
+\end_layout
-\begin_inset LatexCommand \index{\_\_sfr}
+\begin_layout Subsubsection
+xdata
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
\end_inset
- (in/out to 8-bit addresses)
-\end_layout
-\begin_layout Standard
-The Z80
-\begin_inset LatexCommand \index{Z80}
+\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
\end_inset
- family has separate address spaces for memory and
-\emph on
-i
-\emph default
-nput/
-\emph on
-o
-\emph default
-utput memory.
- I/O memory
-\begin_inset LatexCommand \index{I/O memory (Z80, Z180)}
+ / far
+\begin_inset LatexCommand \index{far (storage class)}
\end_inset
-\begin_inset LatexCommand \index{Z80!I/O memory}
+\begin_inset LatexCommand \index{\_\_far (storage class)}
\end_inset
-\begin_inset LatexCommand \index{Z180!I/O memory}
-
-\end_inset
+\end_layout
- is accessed with special instructions, e.g.:
+\begin_layout Standard
+Variables declared with this storage class will be placed in the external
+ RAM.
+ This is the
+\series bold
+default
+\series default
+ storage class for the Large Memory model, e.g.:
\end_layout
\begin_layout Verse
\family typewriter
-sfr at 0x78 IoPort;\InsetSpace ~
-\InsetSpace ~
-/* define a var in I/O space at 78h called IoPort */
-
+__xdata unsigned char test_xdata;
\end_layout
\begin_layout Standard
\begin_layout Verse
\family typewriter
-3E 01\InsetSpace ~
+90s00r00\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+mov\InsetSpace ~
+\InsetSpace ~
+dptr,#_test_xdata
+\newline
+74\InsetSpace ~
+01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-ld a,#0x01
-\newline
-D3 78\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+mov\InsetSpace ~
+\InsetSpace ~
+a,#0x01
+\newline
+F0\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-out (_IoPort),a
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+movx\InsetSpace ~
+@dptr,a
\end_layout
\begin_layout Subsubsection
-banked sfr
-\begin_inset LatexCommand \index{sfr}
+idata
+\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
\end_inset
-\begin_inset LatexCommand \index{\_\_sfr}
+\begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
\end_inset
- (in/out to 16-bit addresses)
+
\end_layout
\begin_layout Standard
-The keyword
-\emph on
-banked
-\emph default
- is used to support 16 bit addresses in I/O memory e.g.:
+Variables declared with this storage class will be allocated into the indirectly
+ addressable portion of the internal ram of a 8051, e.g.:
\end_layout
\begin_layout Verse
\family typewriter
-sfr banked at
-\begin_inset LatexCommand \index{at}
-
-\end_inset
-
-
-\begin_inset LatexCommand \index{\_\_at}
-
-\end_inset
-
- 0x123 IoPort;
+__idata unsigned char test_idata;
\end_layout
\begin_layout Standard
\begin_layout Verse
\family typewriter
-01 23 01\InsetSpace ~
+78r00\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-ld bc,#_IoPort
-\newline
-3E 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+mov\InsetSpace ~
\InsetSpace ~
-ld a,#0x01
+r0,#_test_idata
\newline
-ED 79\InsetSpace ~
+76\InsetSpace ~
+01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-out (c),a
+\InsetSpace ~
+mov\InsetSpace ~
+\InsetSpace ~
+@r0,#0x01
\end_layout
-\begin_layout Subsubsection
-sfr
-\begin_inset LatexCommand \index{sfr}
+\begin_layout Standard
+Please note, the first 128 byte of idata physically access the same RAM
+ as the data memory.
+ The original 8051 had 128 byte idata memory, nowadays most devices have
+ 256 byte idata memory.
+ The stack
+\begin_inset LatexCommand \index{stack}
\end_inset
+ is located in idata memory.
+\end_layout
-\begin_inset LatexCommand \index{\_\_sfr}
+\begin_layout Subsubsection
+pdata
+\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
\end_inset
- (in0/out0 to 8 bit addresses on Z180
-\begin_inset LatexCommand \index{Z180}
-
-\end_inset
-/HD64180
-\begin_inset LatexCommand \index{HD64180 (see Z180)}
+\begin_inset LatexCommand \index{\_\_pdata (mcs51, ds390 storage class)}
\end_inset
-)
-\end_layout
-\begin_layout Standard
-The compiler option -
-\begin_inset ERT
-status collapsed
+\end_layout
\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
+Paged xdata access is just as straightforward as using the other addressing
+ modes of a 8051.
+ It is typically located at the start of xdata and has a maximum size of
+ 256 bytes.
+ The following example writes 0x01 to the pdata variable.
+ Please note, pdata access physically accesses xdata memory.
+ The high byte of the address is determined by port P2
+\begin_inset LatexCommand \index{P2 (mcs51 sfr)}
\end_inset
--portmode
-\begin_inset LatexCommand \index{Z180!Options!-\/-portmode}
+(or in case of some 8051 variants by a separate Special Function Register,
+ see section
+\begin_inset LatexCommand \ref{sub:MCS51-variants}
\end_inset
-=180 (80) and a compiler #pragma\InsetSpace ~
-portmode
-\begin_inset LatexCommand \index{Z180!Pragmas!\#pragma portmode}
+).
+ This is the
+\series bold
+default
+\series default
+ storage class for the Medium Memory model, e.g.:
+\end_layout
-\end_inset
+\begin_layout Verse
- z180 (z80) is used to turn on (off) the Z180/HD64180 port addressing instructio
-ns
\family typewriter
-in0/out0
-\family default
- instead of
-\family typewriter
-in/out
-\family default
-.
- If you include the file z180.h this will be set automatically.
-\begin_inset VSpace bigskip
-\end_inset
-
-
+__pdata unsigned char test_pdata;
\end_layout
-\begin_layout Subsection
-HC08 Storage Class
-\begin_inset LatexCommand \index{HC08!Storage class}
+\begin_layout Standard
+Writing 0x01 to this variable generates the assembly code:
+\end_layout
-\end_inset
+\begin_layout Verse
- Language Extensions
+\family typewriter
+78r00\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov r0,#_test_pdata
+\newline
+74 01\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov a,#0x01
+\newline
+F2\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+movx @r0,a
\end_layout
-\begin_layout Subsubsection
-data
-\begin_inset LatexCommand \index{data (hc08 storage class)}
+\begin_layout Standard
+If the -
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-\begin_inset LatexCommand \index{\_\_data (hc08 storage class)}
+\backslash
+/
+\end_layout
\end_inset
-
-\end_layout
-
-\begin_layout Standard
-The data storage class declares a variable that resides in the first 256
- bytes of memory (the direct page).
- The HC08
-\begin_inset LatexCommand \index{HC08}
+-xstack
+\begin_inset LatexCommand \index{-\/-xstack}
\end_inset
- is most efficient at accessing variables (especially pointers) stored here.
+ option is used the pdata memory area is followed by the xstack memory area
+ and the sum of their sizes is limited to 256 bytes.
\end_layout
\begin_layout Subsubsection
-xdata
-\begin_inset LatexCommand \index{xdata (hc08 storage class)}
+code
+\begin_inset LatexCommand \index{code}
\end_inset
-\begin_inset LatexCommand \index{\_\_xdata (hc08 storage class)}
+\begin_inset LatexCommand \index{\_\_code}
\end_inset
-
+
\end_layout
\begin_layout Standard
-The xdata storage class declares a variable that can reside anywhere in
- memory.
- This is the default if no storage class is specified.
-
-\begin_inset VSpace bigskip
-\end_inset
+'Variables' declared with this storage class will be placed in the code
+ memory:
+\end_layout
+\begin_layout Verse
+\family typewriter
+__code unsigned char test_code;
\end_layout
-\begin_layout Section
-Absolute Addressing
-\begin_inset LatexCommand \index{Absolute addressing}
-
-\end_inset
+\begin_layout Standard
+Read access to this variable generates the assembly code:
+\end_layout
+\begin_layout Verse
+\family typewriter
+90s00r6F\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov dptr,#_test_code
+\newline
+E4\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+clr a
+\newline
+93\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+movc a,@a+dptr
\end_layout
\begin_layout Standard
-Data items can be assigned an absolute address with the
-\emph on
-at
-\begin_inset LatexCommand \index{at}
-\end_inset
+\family typewriter
+char
+\family default
+ indexed arrays of characters in code memory can be accessed efficiently:
+\end_layout
+\begin_layout Verse
-\begin_inset LatexCommand \index{\_\_at}
+\family typewriter
+__code char test_array[] = {'c','h','e','a','p'};
+\end_layout
-\end_inset
+\begin_layout Standard
+Read access to this array using an 8-bit unsigned index generates the assembly
+ code:
+\end_layout
- <address>
-\emph default
- keyword, in addition to a storage class, e.g.:
+\begin_layout Verse
+
+\family typewriter
+E5*00\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov a,_index
\end_layout
\begin_layout Verse
\family typewriter
-xdata
-\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
+90s00r41\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov dptr,#_test_array
+\end_layout
-\end_inset
+\begin_layout Verse
+\family typewriter
+93\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+movc a,@a+dptr
+\end_layout
-\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
+\begin_layout Subsubsection
+bit
+\begin_inset LatexCommand \index{bit}
\end_inset
- at
-\begin_inset LatexCommand \index{at}
+
+\begin_inset LatexCommand \index{\_\_bit}
\end_inset
-\begin_inset LatexCommand \index{\_\_at}
+\end_layout
-\end_inset
+\begin_layout Standard
+This is a data-type and a storage class specifier.
+ When a variable is declared as a bit, it is allocated into the bit addressable
+ memory of 8051, e.g.:
+\end_layout
- 0x7ffe unsigned int chksum;
+\begin_layout Verse
+
+\family typewriter
+__bit test_bit;
\end_layout
\begin_layout Standard
-or, better conforming to ISO/IEC 9899 C:
+Writing 1 to this variable generates the assembly code:
\end_layout
\begin_layout Verse
\family typewriter
-__xdata __at (0x7ffe) unsigned int chksum;
+D2*00\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+setb\InsetSpace ~
+_test_bit
\end_layout
\begin_layout Standard
-In the above example the variable chksum will be located at 0x7ffe and 0x7fff
- of the external ram.
- The compiler does
-\emph on
-not
-\emph default
- reserve any space for variables declared in this way
-\begin_inset Marginal
-status collapsed
+The bit addressable memory consists of 128 bits which are located from 0x20
+ to 0x2f in data memory.
+
+\newline
+Apart from this 8051 specific storage class most architectures support
+ ANSI-C bitfields
+\begin_inset LatexCommand \index{bitfields}
+
+\end_inset
+
+
+\begin_inset Foot
+status open
\begin_layout Standard
+Not really meant as examples, but nevertheless showing what bitfields are
+ about: device/include/mc68hc908qy.h and support/regression/tests/bitfields.c
+\end_layout
-\series bold
-\InsetSpace ~
-!
+\end_inset
+
+.
+ In accordance with ISO/IEC 9899 bits and bitfields without an explicit
+ signed modifier are implemented as unsigned.
\end_layout
+\begin_layout Subsubsection
+sfr
+\begin_inset LatexCommand \index{sfr}
+
\end_inset
- (they are implemented with an equate in the assembler).
- Thus it is left to the programmer to make sure there are no overlaps with
- other variables that are declared without the absolute address.
- The assembler listing file (.lst
-\begin_inset LatexCommand \index{<file>.lst}
+
+\begin_inset LatexCommand \index{\_\_sfr}
\end_inset
-) and the linker output files (.rst
-\begin_inset LatexCommand \index{<file>.rst}
+ / sfr16
+\begin_inset LatexCommand \index{sfr16}
\end_inset
-) and (.map
-\begin_inset LatexCommand \index{<file>.map}
+
+\begin_inset LatexCommand \index{\_\_sfr16}
\end_inset
-) are good places to look for such overlaps.
- Variables with an absolute address are
-\emph on
-not
-\begin_inset Marginal
-status collapsed
+ / sfr32
+\begin_inset LatexCommand \index{sfr32}
-\begin_layout Standard
+\end_inset
-\series bold
-\InsetSpace ~
-!
-\end_layout
+
+\begin_inset LatexCommand \index{\_\_sfr32}
\end_inset
+ / sbit
+\begin_inset LatexCommand \index{\_\_sbit}
-\emph default
- initialized
-\begin_inset LatexCommand \index{Variable initialization}
+\end_inset
+
+
+\begin_inset LatexCommand \index{sbit}
\end_inset
-.
+
\end_layout
\begin_layout Standard
-In case of memory mapped I/O devices the keyword
+Like the bit keyword,
\emph on
-volatile
+sfr / sfr16 / sfr32 / sbit
\emph default
- has to be used to tell the compiler that accesses might not be removed:
+signify both a data-type and storage class, they are used to describe the
+
+\emph on
+s
+\emph default
+pecial
+\emph on
+f
+\emph default
+unction
+\emph on
+r
+\emph default
+egisters and
+\emph on
+s
+\emph default
+pecial
+\emph on
+bit
+\emph default
+ variables of a 8051, eg:
\end_layout
\begin_layout Verse
\family typewriter
-volatile
-\begin_inset LatexCommand \index{volatile}
+__sfr __at
+\begin_inset LatexCommand \index{at}
\end_inset
- __xdata
-\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
-
-\end_inset
- __at
-\begin_inset LatexCommand \index{at}
+\begin_inset LatexCommand \index{\_\_at}
\end_inset
- (0x8000) unsigned char PORTA_8255;
-\end_layout
+ (0x80) P0;\InsetSpace ~
+ /* special function register P0 at location 0x80 */
+\newline
-\begin_layout Standard
-For some architectures (mcs51) array accesses are more efficient if an (xdata/fa
-r) array
-\family typewriter
-\size footnotesize
+\newline
+/* 16 bit
+ special function register combination for timer 0
+\newline
+\InsetSpace ~
+\InsetSpace ~
+ with the high byte at
+ location 0x8C and the low byte at location 0x8A */
+\newline
+__sfr16 __at (0x8C8A)
+ TMR0;
+\newline
-\begin_inset LatexCommand \index{Aligned array}
+\newline
+__sbit __at
+\begin_inset LatexCommand \index{at}
\end_inset
-\family default
-\size default
- starts at a block (256 byte) boundary
-\begin_inset LatexCommand \index{block boundary}
+\begin_inset LatexCommand \index{\_\_at}
\end_inset
- (section
-\begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
+ (0xd7) CY;\InsetSpace ~
+ /* CY (Carry Flag
+\begin_inset LatexCommand \index{Flags}
\end_inset
- has an example).
-\newline
-Absolute addresses can be specified for variables in all
- storage classes, e.g.:
-\end_layout
-
-\begin_layout Verse
-
-\family typewriter
-__bit
-\begin_inset LatexCommand \index{bit}
-
-\end_inset
- __at
-\begin_inset LatexCommand \index{at}
+\begin_inset LatexCommand \index{Carry flag}
\end_inset
- (0x02) bvar;
+) */
\end_layout
\begin_layout Standard
-The above example will allocate the variable at offset 0x02 in the bit-addressab
-le space.
- There is no real advantage to assigning absolute addresses to variables
- in this manner, unless you want strict control over all the variables allocated.
- One possible use would be to write hardware portable code.
- For example, if you have a routine that uses one or more of the microcontroller
- I/O pins, and such pins are different for two different hardwares, you
- can declare the I/O pins in your routine using:
+Special function registers which are located on an address dividable by
+ 8 are bit-addressable, an
+\emph on
+ sbit
+\emph default
+ addresses a specific bit within these sfr.
+\newline
+16 Bit and 32 bit special function
+ register combinations which require a certain access order are better not
+ declared using
+\emph on
+sfr16
+\emph default
+ or
+\emph on
+sfr32.
+
+\emph default
+ Allthough SDCC usually accesses them Least Significant Byte (LSB) first,
+ this is not guaranteed.
+\newline
+
\end_layout
-\begin_layout Verse
+\begin_layout Standard
+Please note, if you use a header file which was written for another compiler
+ then the sfr / sfr16 / sfr32 / sbit Storage Class extensions will most
+ likely be
+\emph on
+not
+\emph default
+compatible.
+ Specifically the syntax
+\family typewriter
+\InsetSpace ~
+sfr P0 = 0x80;\InsetSpace ~
+\family default
+ is compiled
+\emph on
+without warning
+\emph default
+ by SDCC to an assignment of 0x80 to a variable called P0
\family typewriter
-extern volatile
-\begin_inset LatexCommand \index{volatile}
-\end_inset
+\begin_inset Marginal
+status collapsed
- __bit MOSI;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
+\begin_layout Standard
+
+\series bold
\InsetSpace ~
-/* master out, slave in */
+!
+\end_layout
+
+\end_inset
+
+.
+
+\family default
+Nevertheless it is possible to write header files
+\begin_inset LatexCommand \index{Header files}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Include files}
+
+\end_inset
+
+ which can be shared among different compilers (see section
+\begin_inset LatexCommand \ref{sec:Porting-code-to-other-compilers}
+
+\end_inset
+
+).
+
+\end_layout
+
+\begin_layout Subsubsection
+Pointers
+\begin_inset LatexCommand \index{Pointer}
+
+\end_inset
+
+ to MCS51/DS390 specific memory spaces
+\end_layout
+
+\begin_layout Standard
+SDCC allows (via language extensions) pointers to explicitly point to any
+ of the memory spaces
+\begin_inset LatexCommand \index{Memory model}
+
+\end_inset
+
+ of the 8051.
+ In addition to the explicit pointers, the compiler uses (by default) generic
+ pointers which can be used to point to any of the memory spaces.
\newline
-extern volatile __bit MISO;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* master
- in, slave out */
+
\newline
-extern volatile __bit MCLK;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* master clock */
+Pointer
+ declaration examples:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+/* pointer physically in internal ram pointing to object in external ram
+ */
+\newline
+__xdata unsigned char * __data p;
\newline
\newline
-/* Input and
- Output of a byte on a 3-wire serial bus.
+/* pointer physically in external ram
+ pointing to object in internal ram */
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-If needed adapt polarity of clock,
- polarity of data and bit order
+__data unsigned char * __xdata p;
\newline
-\InsetSpace ~
-*/
+
\newline
-unsigned char spi_io(unsigned char out_byte)
-
+/*
+ pointer physically in code rom pointing to data in xdata space */
\newline
-{
+__xdata
+ unsigned char * __code p;
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-unsigned char i=8;
+
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-do {
+/* pointer physically in code space pointing to
+ data in code space */
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-MOSI = out_byte & 0x80;
+__code unsigned char * __code p;
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-out_byte <<= 1;
+
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-MCLK =
- 1;
+/* generic pointer
+ physically located in xdata space */
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* _asm nop _endasm; */\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* for slow peripherals */
+unsigned char * __xdata p;
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-if(MISO)
+
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-out_byte +=
- 1;
+/* generic
+ pointer physically located in default memory space */
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-MCLK = 0;
+unsigned char * p;
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-} while(--i);
+
\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-return out_byte;
+/*
+ the following is a function pointer
+\begin_inset LatexCommand \index{function pointer}
+
+\end_inset
+
+ physically located in data space */
\newline
-}
+char (* __data fp)(void);
\end_layout
\begin_layout Standard
-Then, someplace in the code for the first hardware you would use
-\end_layout
+Well you get the idea.
+
+\newline
-\begin_layout Verse
+\newline
+All unqualified pointers are treated as 3-byte (4-byte for the ds390)
+\emph on
+generic
+\emph default
+ pointers.
+
+\size small
-\family typewriter
-__bit __at
-\begin_inset LatexCommand \index{at}
+\newline
-\end_inset
+\newline
+
+\size default
+The highest order byte of the
+\emph on
+generic
+\emph default
+ pointers contains the data space information.
+ Assembler support routines are called whenever data is stored or retrieved
+ using
+\emph on
+generic
+\emph default
+ pointers.
+ These are useful for developing reusable library
+\begin_inset LatexCommand \index{Libraries}
+\end_inset
-\begin_inset LatexCommand \index{\_\_at}
+ routines.
+ Explicitly specifying the pointer
+\begin_inset LatexCommand \index{pointer}
\end_inset
- (0x80) MOSI;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* I/O port 0, bit 0 */
-\newline
-__bit __at (0x81) MISO;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* I/O port 0,
- bit 1 */
-\newline
-__bit __at (0x82) MCLK;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* I/O port 0, bit 2 */
+ type will generate the most efficient code.
\end_layout
-\begin_layout Standard
-Similarly, for the second hardware you would use
+\begin_layout Subsubsection
+Notes on MCS51 memory
+\begin_inset LatexCommand \index{MCS51 memory}
+
+\end_inset
+
+ layout
\end_layout
-\begin_layout Verse
+\begin_layout Standard
+The 8051 family of microcontrollers have a minimum of 128 bytes of internal
+ RAM memory which is structured as follows:
+\newline
-\family typewriter
-__bit __at (0x83) MOSI;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* I/O port 0, bit 3 */
\newline
-__bit __at (0x91) MISO;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/*
- I/O port 1, bit 1 */
+- Bytes 00-1F - 32 bytes to hold
+ up to 4 banks of the registers R0 to R7,
\newline
-__bit
+- Bytes 20-2F - 16 bytes to hold
+ 128 bit
\begin_inset LatexCommand \index{bit}
\end_inset
- __at (0x92) MCLK;\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-/* I/O port 1, bit 2 */
+ variables and,
+\newline
+- Bytes 30-7F - 80 bytes for general purpose use.
+\newline
+
\end_layout
\begin_layout Standard
-and you can use the same hardware dependent routine without changes, as
- for example in a library.
- This is somehow similar to sbit, but only one absolute address has to be
- specified in the whole project.
-\begin_inset VSpace bigskip
+Additionally some members of the MCS51 family may have up to 128 bytes of
+ additional, indirectly addressable, internal RAM memory (
+\emph on
+idata
+\emph default
+
+\begin_inset LatexCommand \index{idata (mcs51, ds390 storage class)}
+
\end_inset
-\end_layout
+\begin_inset LatexCommand \index{\_\_idata (mcs51, ds390 storage class)}
-\begin_layout Section
-Parameters
-\begin_inset LatexCommand \index{Parameters}
+\end_inset
+
+).
+ Furthermore, some chips may have some built in external memory (
+\emph on
+xdata
+\emph default
+
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
\end_inset
-\begin_inset LatexCommand \index{function parameter}
+\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
\end_inset
- & Local Variables
-\begin_inset LatexCommand \index{local variables}
+) which should not be confused with the internal, directly addressable RAM
+ memory (
+\emph on
+data
+\emph default
+
+\begin_inset LatexCommand \index{data (mcs51, ds390 storage class)}
\end_inset
-\begin_inset LatexCommand \label{sec:Parameters-and-Local-Variables}
+\begin_inset LatexCommand \index{\_\_data (mcs51, ds390 storage class)}
\end_inset
+).
+ Sometimes this built in
+\emph on
+xdata
+\emph default
+ memory has to be activated before using it (you can probably find this
+ information on the datasheet of the microcontroller your are using, see
+ also section
+\begin_inset LatexCommand \ref{sub:Startup-Code}
+
+\end_inset
+\InsetSpace ~
+Startup-Code).
\end_layout
\begin_layout Standard
-Automatic (local) variables and parameters to functions can either be placed
- on the stack or in data-space.
- The default action of the compiler is to place these variables in the internal
- RAM (for small model) or external RAM (for large model).
- This in fact makes them similar to
+Normally SDCC will only use the first bank
+\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
+
+\end_inset
+
+ of registers (register bank 0), but it is possible to specify that other
+ banks of registers (keyword
\emph on
-static
-\begin_inset LatexCommand \index{static}
+using
+\emph default
+
+\emph on
+
+\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
\end_inset
\emph default
- so by default functions are non-reentrant
-\begin_inset LatexCommand \index{reentrant}
+) should be used for example in interrupt
+\begin_inset LatexCommand \index{interrupt}
\end_inset
-.
-
-\newline
-\newline
-They can be placed on the stack
+\begin_inset LatexCommand \index{\_\_interrupt}
+
+\end_inset
+
+ routines.
+ By default, the compiler will place the stack after the last byte of allocated
+ memory for variables.
+ For example, if the first 2 banks of registers are used, and only four
+ bytes are used for
+\emph on
+data
+\emph default
+ variables, it will position the base of the internal stack at address 20
+ (0x14).
+ This implies that as the stack
\begin_inset LatexCommand \index{stack}
\end_inset
- by using the
+ grows, it will use up the remaining register banks, and the 16 bytes used
+ by the 128 bit variables, and 80 bytes for general purpose use.
+ If any bit variables are used, the data variables will be placed in unused
+ register banks and after the byte holding the last bit variable.
+ For example, if register banks 0 and 1 are used, and there are 9 bit variables
+ (two bytes used),
\emph on
- -
+data
+\emph default
+ variables will be placed starting from address 0x10 to 0x20 and continue
+ at address 0x22.
+ You can also use -
\begin_inset ERT
status collapsed
\end_inset
--stack-auto
-\begin_inset LatexCommand \index{-\/-stack-auto}
+-data-loc
+\begin_inset LatexCommand \index{-\/-data-loc <Value>}
\end_inset
-
-\emph default
- option, by using
+ to specify the start address of the
\emph on
-#pragma\InsetSpace ~
-stackauto
+data
\emph default
+ and -
+\begin_inset ERT
+status collapsed
-\begin_inset LatexCommand \index{\#pragma stackauto}
+\begin_layout Standard
-\end_inset
- or by using the
-\emph on
-reentrant
-\begin_inset LatexCommand \index{reentrant}
+\backslash
+/
+\end_layout
\end_inset
+-iram-size
+\begin_inset LatexCommand \index{-\/-iram-size <Value>}
-\emph default
- keyword in the function declaration, e.g.:
-\end_layout
-
-\begin_layout Verse
+\end_inset
-\family typewriter
-unsigned char foo(char i) __reentrant
-\newline
-{
-\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-...
+ to specify the size of the total internal RAM (
+\emph on
+data
+\emph default
++
+\emph on
+idata
+\emph default
+).
\newline
-}
+
\end_layout
\begin_layout Standard
-Since stack space on 8051 is limited, the
-\emph on
-reentrant
-\emph default
-keyword or the
-\emph on
- -
+By default the 8051 linker will place the stack after the last byte of (i)data
+ variables.
+ Option -
\begin_inset ERT
status collapsed
\end_inset
--stack-auto
-\emph default
- option should be used sparingly.
- Note that the reentrant keyword just means that the parameters & local
- variables will be allocated to the stack, it
-\emph on
-does not
-\emph default
- mean that the function is register bank
-\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
+-stack-loc
+\begin_inset LatexCommand \index{-\/-stack-loc <Value>}
\end_inset
- independent.
-\newline
-
-\newline
-Local variables
-\begin_inset LatexCommand \index{local variables}
-
-\end_inset
+ allows you to specify the start of the stack, i.e.
+ you could start it after any data in the general purpose area.
+ If your microcontroller has additional indirectly addressable internal
+ RAM (
+\emph on
+idata
+\emph default
+) you can place the stack on it.
+ You may also need to use -
+\begin_inset ERT
+status collapsed
- can be assigned storage classes and absolute
-\begin_inset LatexCommand \index{Absolute addressing}
+\begin_layout Standard
-\end_inset
- addresses, e.g.:
+\backslash
+/
\end_layout
-\begin_layout Verse
+\end_inset
-\family typewriter
-unsigned char foo()
-\newline
-{
-\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-__xdata unsigned char i;
-\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-__bit bvar;
-\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-__data __at
-\begin_inset LatexCommand \index{at}
+-xdata-loc
+\begin_inset LatexCommand \index{-\/-xdata-loc<Value>}
\end_inset
- (0x31) unsigned char j;
-\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-...
-
-\newline
-}
-\end_layout
-
-\begin_layout Standard
-In the above example the variable
-\emph on
-i
-\emph default
- will be allocated in the external ram,
-\emph on
-bvar
-\emph default
- in bit addressable space and
+ to set the start address of the external RAM (
\emph on
- j
+xdata
\emph default
- in internal ram.
- When compiled with
-\emph on
--
+) and -
\begin_inset ERT
status collapsed
\end_inset
--stack-auto
-\emph default
- or when a function is declared as
-\emph on
-reentrant
-\emph default
- this should only be done for static variables.
-\end_layout
+-xram-size
+\begin_inset LatexCommand \index{-\/-xram-size <Value>}
+
+\end_inset
+
+ to specify its size.
+ Same goes for the code memory, using -
+\begin_inset ERT
+status collapsed
\begin_layout Standard
-Parameters
-\begin_inset LatexCommand \index{function parameter}
+
+
+\backslash
+/
+\end_layout
\end_inset
- however are not allowed any storage class
-\begin_inset LatexCommand \index{Storage class}
+-code-loc
+\begin_inset LatexCommand \index{-\/-code-loc <Value>}
\end_inset
-, (storage classes for parameters will be ignored), their allocation is
- governed by the memory model in use, and the reentrancy options.
-\end_layout
+ and -
+\begin_inset ERT
+status collapsed
\begin_layout Standard
-It is however allowed to use bit parameters in reentrant functions and also
- non-static local bit variables are supported.
- Efficient use is limited to 8 semi-bitregisters in bit space.
- They are pushed and popped to stack
-\begin_inset LatexCommand \index{stack}
-\end_inset
- as a single byte just like the normal registers.
+\backslash
+/
\end_layout
-\begin_layout Section
-Overlaying
-\begin_inset LatexCommand \label{sub:Overlaying}
-
\end_inset
-
-\begin_inset LatexCommand \index{Overlaying}
+-code-size
+\begin_inset LatexCommand \index{-\/-code-size <Value>}
\end_inset
-
+.
+ If in doubt, don't specify any options and see if the resulting memory
+ layout is appropriate, then you can adjust it.
\end_layout
\begin_layout Standard
-For non-reentrant
-\begin_inset LatexCommand \index{reentrant}
+The linker generates two files with memory allocation information.
+ The first, with extension .map
+\begin_inset LatexCommand \index{<file>.map}
\end_inset
- functions SDCC will try to reduce internal ram space usage by overlaying
- parameters and local variables of a function (if possible).
- Parameters and local variables
-\begin_inset LatexCommand \index{local variables}
+ shows all the variables and segments.
+ The second with extension .mem
+\begin_inset LatexCommand \index{<file>.mem}
\end_inset
- of a function will be allocated to an overlayable segment if the function
- has
-\emph on
-no other function calls and the function is non-reentrant and the memory
- model
-\begin_inset LatexCommand \index{Memory model}
-
+ shows the final memory layout.
+ The linker will complain either if memory segments overlap, there is not
+ enough memory, or there is not enough space for stack.
+ If you get any linking warnings and/or errors related to stack or segments
+ allocation, take a look at either the .map or .mem files to find out what
+ the problem is.
+ The .mem file may even suggest a solution to the problem.
+\begin_inset VSpace bigskip
\end_inset
- is small.
-
-\emph default
- If an explicit storage class
-\begin_inset LatexCommand \index{Storage class}
-
-\end_inset
- is specified for a local variable, it will NOT be overlayed.
\end_layout
-\begin_layout Standard
-Note that the compiler (not the linkage editor) makes the decision for overlayin
-g the data items.
- Functions that are called from an interrupt service routine
-\begin_inset Marginal
-status collapsed
+\begin_layout Subsection
+Z80/Z180 Storage Class
+\begin_inset LatexCommand \index{Z80!Storage class}
-\begin_layout Standard
+\end_inset
-\series bold
-!
+ Language Extensions
\end_layout
+\begin_layout Subsubsection
+sfr
+\begin_inset LatexCommand \index{sfr}
+
\end_inset
- should be preceded by a #pragma\InsetSpace ~
-nooverlay
-\begin_inset LatexCommand \index{\#pragma nooverlay}
+
+\begin_inset LatexCommand \index{\_\_sfr}
\end_inset
- if they are not reentrant.
+ (in/out to 8-bit addresses)
\end_layout
\begin_layout Standard
-Also note that the compiler does not do any processing of inline assembler
- code, so the compiler might incorrectly assign local variables and parameters
- of a function into the overlay segment if the inline assembler code calls
- other c-functions that might use the overlay.
- In that case the #pragma\InsetSpace ~
-nooverlay should be used.
-\end_layout
+The Z80
+\begin_inset LatexCommand \index{Z80}
-\begin_layout Standard
-Parameters and local variables of functions that contain 16 or 32 bit multiplica
-tion
-\begin_inset LatexCommand \index{Multiplication}
+\end_inset
+
+ family has separate address spaces for memory and
+\emph on
+i
+\emph default
+nput/
+\emph on
+o
+\emph default
+utput memory.
+ I/O memory
+\begin_inset LatexCommand \index{I/O memory (Z80, Z180)}
\end_inset
- or division
-\begin_inset LatexCommand \index{Division}
+
+\begin_inset LatexCommand \index{Z80!I/O memory}
\end_inset
- will NOT be overlayed since these are implemented using external functions,
- e.g.:
+
+\begin_inset LatexCommand \index{Z180!I/O memory}
+
+\end_inset
+
+ is accessed with special instructions, e.g.:
\end_layout
\begin_layout Verse
\family typewriter
-#pragma save
-\newline
-#pragma nooverlay
-\begin_inset LatexCommand \index{\#pragma nooverlay}
-
-\end_inset
-
-
-\newline
-void set_error(unsigned char errcd)
-\newline
-{
-\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
+sfr at 0x78 IoPort;\InsetSpace ~
\InsetSpace ~
-P3 = errcd;
-\newline
-}
-\newline
-#pragma restore
-\newline
+/* define a var in I/O space at 78h called IoPort */
+
+\end_layout
-\newline
-void
- some_isr () __interrupt
-\begin_inset LatexCommand \index{interrupt}
+\begin_layout Standard
+Writing 0x01 to this variable generates the assembly code:
+\end_layout
-\end_inset
+\begin_layout Verse
- (2)
-\newline
-{
-\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
+\family typewriter
+3E 01\InsetSpace ~
\InsetSpace ~
-...
-\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-set_error(10);
+ld a,#0x01
\newline
+D3 78\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-...
-
-\newline
-}
+\InsetSpace ~
+out (_IoPort),a
\end_layout
-\begin_layout Standard
-In the above example the parameter
-\emph on
-errcd
-\emph default
- for the function
-\emph on
-set_error
-\emph default
- would be assigned to the overlayable segment if the #pragma\InsetSpace ~
-nooverlay was
- not present, this could cause unpredictable runtime behavior when called
- from an interrupt service routine.
- The #pragma\InsetSpace ~
-nooverlay ensures that the parameters and local variables for
- the function are NOT overlayed.
-\begin_inset VSpace bigskip
+\begin_layout Subsubsection
+banked sfr
+\begin_inset LatexCommand \index{sfr}
+
\end_inset
+\begin_inset LatexCommand \index{\_\_sfr}
+
+\end_inset
+
+ (in/out to 16-bit addresses)
\end_layout
-\begin_layout Section
-Interrupt Service Routines
-\begin_inset LatexCommand \label{sub:Interrupt-Service-Routines}
+\begin_layout Standard
+The keyword
+\emph on
+banked
+\emph default
+ is used to support 16 bit addresses in I/O memory e.g.:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+sfr banked at
+\begin_inset LatexCommand \index{at}
\end_inset
-\end_layout
+\begin_inset LatexCommand \index{\_\_at}
-\begin_layout Subsection
-General Information
+\end_inset
+
+ 0x123 IoPort;
\end_layout
\begin_layout Standard
-SDCC allows
-\emph on
-i
-\emph default
-nterrupt
-\emph on
-s
-\emph default
-ervice
-\emph on
-r
-\emph default
-outines to be coded in C, with some extended keywords.
+Writing 0x01 to this variable generates the assembly code:
\end_layout
\begin_layout Verse
\family typewriter
-void timer_isr (void) __interrupt (1) __using (1)
-\newline
-{
+01 23 01\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+ld bc,#_IoPort
\newline
+3E 01\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-...
-
+\InsetSpace ~
+ld a,#0x01
\newline
-}
+ED 79\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+out (c),a
\end_layout
-\begin_layout Standard
-The optional number following the
-\emph on
-interrupt
-\begin_inset LatexCommand \index{interrupt}
+\begin_layout Subsubsection
+sfr
+\begin_inset LatexCommand \index{sfr}
\end_inset
-\begin_inset LatexCommand \index{\_\_interrupt}
+\begin_inset LatexCommand \index{\_\_sfr}
\end_inset
-
-\emph default
- keyword is the interrupt number this routine will service.
- When present, the compiler will insert a call to this routine in the interrupt
- vector table
-\begin_inset LatexCommand \index{interrupt vector table}
+ (in0/out0 to 8 bit addresses on Z180
+\begin_inset LatexCommand \index{Z180}
\end_inset
- for the interrupt number specified.
- If you have multiple source files in your project, interrupt service routines
- can be present in any of them, but a prototype of the isr MUST be present
- or included in the file that contains the function
-\emph on
-main
-\emph default
-.
- The optional (8051 specific) keyword
-\emph on
-using
-\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
+/HD64180
+\begin_inset LatexCommand \index{HD64180 (see Z180)}
\end_inset
+)
+\end_layout
-\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
+\begin_layout Standard
+The compiler option -
+\begin_inset ERT
+status collapsed
-\end_inset
+\begin_layout Standard
-\emph default
- can be used to tell the compiler to use the specified register bank when
- generating code for this function.
-
-\newline
-Interrupt service routines open the door for some very interesting bugs:
+\backslash
+/
\end_layout
-\begin_layout Subsubsection
-\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-volatile}
-
\end_inset
-Common interrupt pitfall: variable not declared
-\emph on
-volatile
-\end_layout
+-portmode
+\begin_inset LatexCommand \index{Z180!Options!-\/-portmode}
-\begin_layout Standard
-If an interrupt service routine changes variables which are accessed by
- other functions these variables have to be declared
-\emph on
-volatile
-\emph default
+\end_inset
-\begin_inset LatexCommand \index{volatile}
+=180 (80) and a compiler #pragma\InsetSpace ~
+portmode
+\begin_inset LatexCommand \index{Z180!Pragmas!\#pragma portmode}
\end_inset
+ z180 (z80) is used to turn on (off) the Z180/HD64180 port addressing instructio
+ns
+\family typewriter
+in0/out0
+\family default
+ instead of
+\family typewriter
+in/out
+\family default
.
- See
-\begin_inset LatexCommand \url{http://en.wikipedia.org/wiki/Volatile_variable}
-
+ If you include the file z180.h this will be set automatically.
+\begin_inset VSpace bigskip
\end_inset
- .
+
\end_layout
-\begin_layout Subsubsection
-\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-atomic}
+\begin_layout Subsection
+HC08 Storage Class
+\begin_inset LatexCommand \index{HC08!Storage class}
\end_inset
-Common interrupt pitfall:
-\emph on
-non-atomic access
+ Language Extensions
\end_layout
-\begin_layout Standard
-If the access to these variables is not
-\emph on
-atomic
-\begin_inset LatexCommand \index{atomic}
-
-\end_inset
-
+\begin_layout Subsubsection
+data
+\begin_inset LatexCommand \index{data (hc08 storage class)}
-\emph default
- (i.e.
- the processor needs more than one instruction for the access and could
- be interrupted while accessing the variable) the interrupt must be disabled
- during the access to avoid inconsistent data.
-
-\newline
-Access to 16 or 32 bit variables is obviously not atomic on 8 bit CPUs
- and should be protected by disabling interrupts.
- You're not automatically on the safe side if you use 8 bit variables though.
- We need an example here: f.e.
- on the 8051 the harmless looking
-\begin_inset Quotes srd
\end_inset
-\family typewriter
-flags\InsetSpace ~
-|=\InsetSpace ~
-0x80;
-\family default
-
-\begin_inset Quotes sld
-\end_inset
+\begin_inset LatexCommand \index{\_\_data (hc08 storage class)}
- is not atomic if
-\family typewriter
-flags
-\family default
- resides in xdata.
- Setting
-\begin_inset Quotes srd
\end_inset
+
+\end_layout
-\family typewriter
-flags\InsetSpace ~
-|=\InsetSpace ~
-0x40;
-\family default
-
-\begin_inset Quotes sld
-\end_inset
+\begin_layout Standard
+The data storage class declares a variable that resides in the first 256
+ bytes of memory (the direct page).
+ The HC08
+\begin_inset LatexCommand \index{HC08}
- from within an interrupt routine might get lost if the interrupt occurs
- at the wrong time.
-
-\begin_inset Quotes sld
\end_inset
+ is most efficient at accessing variables (especially pointers) stored here.
+\end_layout
-\family typewriter
-counter\InsetSpace ~
-+=\InsetSpace ~
-8;
-\family default
+\begin_layout Subsubsection
+xdata
+\begin_inset LatexCommand \index{xdata (hc08 storage class)}
-\begin_inset Quotes srd
\end_inset
- is not atomic on the 8051 even if
-\family typewriter
-counter
-\family default
- is located in data memory.
-\newline
-Bugs like these are hard to reproduce and can
- cause a lot of trouble.
-
-\end_layout
-\begin_layout Subsubsection
-\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-stack-overflow}
+\begin_inset LatexCommand \index{\_\_xdata (hc08 storage class)}
\end_inset
-Common interrupt pitfall:
-\emph on
-stack overflow
+
\end_layout
\begin_layout Standard
-The return address and the registers used in the interrupt service routine
- are saved on the stack
-\begin_inset LatexCommand \index{stack}
-
+The xdata storage class declares a variable that can reside anywhere in
+ memory.
+ This is the default if no storage class is specified.
+
+\begin_inset VSpace bigskip
\end_inset
- so there must be sufficient stack space.
- If there isn't variables or registers (or even the return address itself)
- will be corrupted.
- This
-\emph on
-stack overflow
-\emph default
-\begin_inset LatexCommand \index{stack overflow}
+\end_layout
-\end_inset
+\begin_layout Section
+Other SDCC language extensions
+\begin_inset LatexCommand \index{Other SDCC language extensions}
- is most likely to happen if the interrupt occurs during the
-\begin_inset Quotes sld
\end_inset
-deepest
-\begin_inset Quotes srd
-\end_inset
- subroutine when the stack is already in use for f.e.
- many return addresses.
\end_layout
-\begin_layout Subsubsection
-\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-reentrant}
-
-\end_inset
-
-Common interrupt pitfall:
-\emph on
-use of non-reentrant functions
+\begin_layout Subsection
+Binary constants
\end_layout
\begin_layout Standard
-A special note here, int (16 bit) and long (32 bit) integer division
-\begin_inset LatexCommand \index{Division}
-
-\end_inset
-
-, multiplication
-\begin_inset LatexCommand \index{Multiplication}
-
-\end_inset
-
- & modulus
-\begin_inset LatexCommand \index{Modulus}
-
-\end_inset
-
- and floating-point
-\begin_inset LatexCommand \index{Floating point support}
-
-\end_inset
-
- operations are implemented using external support routines.
- If an interrupt service routine needs to do any of these operations then
- the support routines (as mentioned in a following section) will have to
- be recompiled using the
-\emph on
- -
-\begin_inset ERT
-status collapsed
+SDCC supports the use of binary constants, such as 0b01100010.
+ This feature is only enabled when the compiler is invoked using --std-sdccxx.
+\end_layout
\begin_layout Standard
+\begin_inset VSpace bigskip
+\end_inset
-\backslash
-/
\end_layout
-\end_inset
-
--stack-auto
-\begin_inset LatexCommand \index{-\/-stack-auto}
+\begin_layout Section
+Absolute Addressing
+\begin_inset LatexCommand \index{Absolute addressing}
\end_inset
-\emph default
- option and the source file will need to be compiled using the
-\emph on
--
-\begin_inset ERT
-status collapsed
+\end_layout
\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
+Data items can be assigned an absolute address with the
+\emph on
+at
+\begin_inset LatexCommand \index{at}
\end_inset
--int-long-reent
-\emph default
-
-\begin_inset LatexCommand \index{-\/-int-long-reent}
-
-\end_inset
- compiler option.
-
-\newline
-Note, the type promotion
-\begin_inset LatexCommand \index{type promotion}
+\begin_inset LatexCommand \index{\_\_at}
\end_inset
- required by ANSI C can cause 16 bit routines to be used
-\begin_inset Marginal
-status collapsed
-
-\begin_layout Standard
-
-\series bold
-\InsetSpace ~
-!
+ <address>
+\emph default
+ keyword, in addition to a storage class, e.g.:
\end_layout
-\end_inset
+\begin_layout Verse
- without the programmer being aware of it.
- See f.e.
- the cast
\family typewriter
-(unsigned char)(tail-1)
-\family default
- within the if clause in section
-\begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
+xdata
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
\end_inset
-.
-\end_layout
-\begin_layout Standard
-Calling other functions from an interrupt service routine is not recommended,
- avoid it if possible.
- Note that when some function is called from an interrupt service routine
- it should be preceded by a #pragma\InsetSpace ~
-nooverlay
-\begin_inset LatexCommand \index{\#pragma nooverlay}
+\begin_inset LatexCommand \index{\_\_xdata (mcs51, ds390 storage class)}
\end_inset
- if it is not reentrant.
- Furthermore nonreentrant functions should not be called from the main program
- while the interrupt service routine might be active.
- They also must not be called from low priority interrupt service routines
- while a high priority interrupt service routine might be active.
- You could use semaphores or make the function
-\emph on
- critical
-\emph default
- if all parameters are passed in registers.
-\newline
- Also see section
-\begin_inset LatexCommand \ref{sub:Overlaying}
+ at
+\begin_inset LatexCommand \index{at}
\end_inset
-\InsetSpace ~
-about Overlaying and section
-\begin_inset LatexCommand \ref{sub:Functions-using-private-banks}
-\end_inset
+\begin_inset LatexCommand \index{\_\_at}
-\InsetSpace ~
-about Functions using private register banks.
-\begin_inset VSpace bigskip
\end_inset
-
-\end_layout
-
-\begin_layout Subsection
-MCS51/DS390 Interrupt Service Routines
+ 0x7ffe unsigned int chksum;
\end_layout
\begin_layout Standard
-Interrupt
-\begin_inset LatexCommand \index{interrupt}
-
-\end_inset
-
- numbers and the corresponding address & descriptions for the Standard 8051/8052
- are listed below.
- SDCC will automatically adjust the
-\begin_inset LatexCommand \index{interrupt vector table}
-
-\end_inset
+or, better conforming to ISO/IEC 9899 C:
+\end_layout
- to the maximum interrupt number specified.
-\newline
+\begin_layout Verse
+\family typewriter
+__xdata __at (0x7ffe) unsigned int chksum;
\end_layout
\begin_layout Standard
-\align center
-\begin_inset Tabular
-<lyxtabular version="3" rows="9" columns="3">
-<features>
-<column alignment="center" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" width="0in">
-<column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+In the above example the variable chksum will be located at 0x7ffe and 0x7fff
+ of the external ram.
+ The compiler does
+\emph on
+not
+\emph default
+ reserve any space for variables declared in this way
+\begin_inset Marginal
+status collapsed
\begin_layout Standard
-Interrupt #
+
+\series bold
+\InsetSpace ~
+!
\end_layout
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-Description
-\end_layout
+ (they are implemented with an equate in the assembler).
+ Thus it is left to the programmer to make sure there are no overlaps with
+ other variables that are declared without the absolute address.
+ The assembler listing file (.lst
+\begin_inset LatexCommand \index{<file>.lst}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-Vector Address
-\end_layout
+) and the linker output files (.rst
+\begin_inset LatexCommand \index{<file>.rst}
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-0
-\end_layout
+) and (.map
+\begin_inset LatexCommand \index{<file>.map}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-External 0
+) are good places to look for such overlaps.
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-0x0003
-\end_layout
+If however you provide an initializer
+\begin_inset LatexCommand \index{Variable initialization}
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-1
+ actual memory allocation will take place and overlaps will be detected
+ by the linker.
+ E.g.:
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+\begin_layout Verse
-\begin_layout Standard
-Timer 0
-\end_layout
+\family typewriter
+__code __at (0x7ff0) char Id[5] =
+\begin_inset Quotes sld
+\end_inset
+SDCC
+\begin_inset Quotes srd
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-0x000b
+;
\end_layout
-\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-2
+In the above example the variable Id will be located from 0x7ff0 to 0x7ff4
+ in code memory.
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-External 1
+In case of memory mapped I/O devices the keyword
+\emph on
+volatile
+\emph default
+ has to be used to tell the compiler that accesses might not be removed:
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
+\begin_layout Verse
-\begin_layout Standard
-0x0013
-\end_layout
+\family typewriter
+volatile
+\begin_inset LatexCommand \index{volatile}
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-3
-\end_layout
+ __xdata
+\begin_inset LatexCommand \index{xdata (mcs51, ds390 storage class)}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-Timer 1
-\end_layout
+ __at
+\begin_inset LatexCommand \index{at}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-0x001b
+ (0x8000) unsigned char PORTA_8255;
\end_layout
-\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-4
-\end_layout
+For some architectures (mcs51) array accesses are more efficient if an (xdata/fa
+r) array
+\family typewriter
+\size footnotesize
+
+\begin_inset LatexCommand \index{Aligned array}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-Serial
-\end_layout
+
+\family default
+\size default
+ starts at a block (256 byte) boundary
+\begin_inset LatexCommand \index{block boundary}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-0x0023
-\end_layout
+ (section
+\begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-5
+ has an example).
+\newline
+Absolute addresses can be specified for variables in all
+ storage classes, e.g.:
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+\begin_layout Verse
-\begin_layout Standard
-Timer 2 (8052)
-\end_layout
+\family typewriter
+__bit
+\begin_inset LatexCommand \index{bit}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-0x002b
-\end_layout
+ __at
+\begin_inset LatexCommand \index{at}
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-...
+ (0x02) bvar;
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-
+The above example will allocate the variable at offset 0x02 in the bit-addressab
+le space.
+ There is no real advantage to assigning absolute addresses to variables
+ in this manner, unless you want strict control over all the variables allocated.
+ One possible use would be to write hardware portable code.
+ For example, if you have a routine that uses one or more of the microcontroller
+ I/O pins, and such pins are different for two different hardwares, you
+ can declare the I/O pins in your routine using:
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
+\begin_layout Verse
-\begin_layout Standard
-...
-\end_layout
+\family typewriter
+extern volatile
+\begin_inset LatexCommand \index{volatile}
\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
+
+ __bit MOSI;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* master out, slave in */
+\newline
+extern volatile __bit MISO;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* master
+ in, slave out */
+\newline
+extern volatile __bit MCLK;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* master clock */
+\newline
+
+\newline
+/* Input and
+ Output of a byte on a 3-wire serial bus.
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+If needed adapt polarity of clock,
+ polarity of data and bit order
+\newline
+\InsetSpace ~
+*/
+\newline
+unsigned char spi_io(unsigned char out_byte)
+
+\newline
+{
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+unsigned char i=8;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+do {
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+MOSI = out_byte & 0x80;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+out_byte <<= 1;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+MCLK =
+ 1;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* _asm nop _endasm; */\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* for slow peripherals */
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+if(MISO)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+out_byte +=
+ 1;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+MCLK = 0;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+} while(--i);
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+return out_byte;
+\newline
+}
+\end_layout
\begin_layout Standard
-n
+Then, someplace in the code for the first hardware you would use
\end_layout
+\begin_layout Verse
+
+\family typewriter
+__bit __at
+\begin_inset LatexCommand \index{at}
+
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-\end_layout
+\begin_inset LatexCommand \index{\_\_at}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
+
+ (0x80) MOSI;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* I/O port 0, bit 0 */
+\newline
+__bit __at (0x81) MISO;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* I/O port 0,
+ bit 1 */
+\newline
+__bit __at (0x82) MCLK;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* I/O port 0, bit 2 */
+\end_layout
\begin_layout Standard
-0x0003 + 8*n
+Similarly, for the second hardware you would use
\end_layout
-\end_inset
-</cell>
-</row>
-</lyxtabular>
+\begin_layout Verse
+
+\family typewriter
+__bit __at (0x83) MOSI;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* I/O port 0, bit 3 */
+\newline
+__bit __at (0x91) MISO;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/*
+ I/O port 1, bit 1 */
+\newline
+__bit
+\begin_inset LatexCommand \index{bit}
\end_inset
+ __at (0x92) MCLK;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+/* I/O port 1, bit 2 */
+\end_layout
+
+\begin_layout Standard
+and you can use the same hardware dependent routine without changes, as
+ for example in a library.
+ This is somehow similar to sbit, but only one absolute address has to be
+ specified in the whole project.
+\begin_inset VSpace bigskip
+\end_inset
-\newline
\end_layout
-\begin_layout Standard
-If the interrupt service routine is defined without
-\emph on
-using
-\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
+\begin_layout Section
+Parameters
+\begin_inset LatexCommand \index{Parameters}
\end_inset
-\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
+\begin_inset LatexCommand \index{function parameter}
+
+\end_inset
+
+ & Local Variables
+\begin_inset LatexCommand \index{local variables}
+
+\end_inset
+
+
+\begin_inset LatexCommand \label{sec:Parameters-and-Local-Variables}
\end_inset
-\emph default
- a register bank or with register bank 0 (
-\emph on
-using
-\emph default
- 0), the compiler will save the registers used by itself on the stack upon
- entry and restore them at exit, however if such an interrupt service routine
- calls another function then the entire register bank will be saved on the
- stack.
- This scheme may be advantageous for small interrupt service routines which
- have low register usage.
\end_layout
\begin_layout Standard
-If the interrupt service routine is defined to be using a specific register
- bank then only
+Automatic (local) variables and parameters to functions can either be placed
+ on the stack or in data-space.
+ The default action of the compiler is to place these variables in the internal
+ RAM (for small model) or external RAM (for medium or large model).
+ This in fact makes them similar to
\emph on
-a, b, dptr
-\emph default
- & psw are saved and restored, if such an interrupt service routine calls
- another function (using another register bank) then the entire register
- bank of the called function will be saved on the stack
-\begin_inset LatexCommand \index{stack}
+static
+\begin_inset LatexCommand \index{static}
\end_inset
-.
- This scheme is recommended for larger interrupt service routines.
-\begin_inset VSpace bigskip
-\end_inset
+\emph default
+ so by default functions are non-reentrant
+\begin_inset LatexCommand \index{reentrant}
-\end_layout
+\end_inset
-\begin_layout Subsection
-HC08
-\begin_inset LatexCommand \index{HC08}
+.
+
+\newline
+
+\newline
+They can be placed on the stack
+\begin_inset LatexCommand \index{stack}
\end_inset
- Interrupt Service Routines
-\end_layout
+ by using the
+\emph on
+ -
+\begin_inset ERT
+status collapsed
\begin_layout Standard
-Since the number of interrupts
-\begin_inset LatexCommand \index{HC08!interrupt}
-\end_inset
- available is chip specific and the interrupt vector table always ends at
- the last byte of memory, the interrupt numbers corresponds to the interrupt
- vectors in reverse order of address.
- For example, interrupt 1 will use the interrupt vector at 0xfffc, interrupt
- 2 will use the interrupt vector at 0xfffa, and so on.
- However, interrupt 0 (the reset vector at 0xfffe) is not redefinable in
- this way; instead see section
-\begin_inset LatexCommand \ref{sub:Startup-Code}
+\backslash
+/
+\end_layout
\end_inset
- for details on customizing startup.
-\begin_inset VSpace bigskip
-\end_inset
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+\end_inset
-\end_layout
-\begin_layout Subsection
-Z80 Interrupt Service Routines
-\end_layout
+\emph default
+ option, by using
+\emph on
+#pragma\InsetSpace ~
+stackauto
+\emph default
-\begin_layout Standard
-The Z80
-\begin_inset LatexCommand \index{Z80}
+\begin_inset LatexCommand \index{\#pragma stackauto}
\end_inset
- uses several different methods for determining the correct interrupt
-\begin_inset LatexCommand \index{Z80!interrupt}
+ or by using the
+\emph on
+reentrant
+\begin_inset LatexCommand \index{reentrant}
\end_inset
- vector depending on the hardware implementation.
- Therefore, SDCC ignores the optional interrupt number and does not attempt
- to generate an interrupt vector table.
-\end_layout
-\begin_layout Standard
-By default, SDCC generates code for a maskable interrupt, which uses a RETI
- instruction to return from the interrupt.
- To write an interrupt handler for the non-maskable interrupt, which needs
- a RETN instruction instead, add the
-\emph on
-critical
\emph default
- keyword:
+ keyword in the function declaration, e.g.:
\end_layout
\begin_layout Verse
\family typewriter
-void nmi_isr (void) critical interrupt
+unsigned char foo(char i) __reentrant
\newline
{
\newline
\end_layout
\begin_layout Standard
-However if you need to create a non-interruptable interrupt service routine
- you would also require the
+Since stack space on 8051 is limited, the
\emph on
-critical
+reentrant
\emph default
- keyword.
- To distinguish between this and an nmi_isr you must provide an interrupt
- number.
-\begin_inset VSpace bigskip
-\end_inset
+keyword or the
+\emph on
+ -
+\begin_inset ERT
+status collapsed
+\begin_layout Standard
-\end_layout
-\begin_layout Section
-Enabling and Disabling Interrupts
+\backslash
+/
\end_layout
-\begin_layout Subsection
-Critical Functions and Critical Statements
-\end_layout
+\end_inset
-\begin_layout Standard
-A special keyword may be associated with a block or a function declaring
- it as
+-stack-auto
+\emph default
+ option should be used sparingly.
+ Note that the reentrant keyword just means that the parameters & local
+ variables will be allocated to the stack, it
\emph on
-critical
+does not
\emph default
-.
- SDCC will generate code to disable all interrupts
-\begin_inset LatexCommand \index{interrupt}
+ mean that the function is register bank
+\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
\end_inset
- upon entry to a critical function and restore the interrupt enable to the
- previous state before returning.
- Nesting critical functions will need one additional byte on the stack
-\begin_inset LatexCommand \index{stack}
-
-\end_inset
+ independent.
+\newline
- for each call.
-\end_layout
+\newline
+Local variables
+\begin_inset LatexCommand \index{local variables}
-\begin_layout Verse
+\end_inset
-\family typewriter
-int foo () __critical
-\begin_inset LatexCommand \index{critical}
+ can be assigned storage classes and absolute
+\begin_inset LatexCommand \index{Absolute addressing}
\end_inset
+ addresses, e.g.:
+\end_layout
-\begin_inset LatexCommand \index{\_\_critical}
-
-\end_inset
+\begin_layout Verse
-
+\family typewriter
+unsigned char foo()
\newline
-{
+{
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-...
-
+__xdata unsigned char i;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+__bit bvar;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+__data __at
+\begin_inset LatexCommand \index{at}
+
+\end_inset
+
+ (0x31) unsigned char j;
\newline
\InsetSpace ~
\InsetSpace ~
\end_layout
\begin_layout Standard
-The critical attribute maybe used with other attributes like
+In the above example the variable
\emph on
-reentrant.
+i
\emph default
-
-\newline
-The keyword
+ will be allocated in the external ram,
\emph on
-critical
+bvar
\emph default
- may also be used to disable interrupts more locally:
+ in bit addressable space and
+\emph on
+ j
+\emph default
+ in internal ram.
+ When compiled with
+\emph on
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
\end_layout
-\begin_layout Verse
+\end_inset
-\family typewriter
-__critical{ i++; }
+-stack-auto
+\emph default
+ or when a function is declared as
+\emph on
+reentrant
+\emph default
+ this should only be done for static variables.
\end_layout
\begin_layout Standard
-More than one statement could have been included in the block.
-\end_layout
+Parameters
+\begin_inset LatexCommand \index{function parameter}
-\begin_layout Subsection
-Enabling and Disabling Interrupts directly
+\end_inset
+
+ however are not allowed any storage class
+\begin_inset LatexCommand \index{Storage class}
+
+\end_inset
+
+, (storage classes for parameters will be ignored), their allocation is
+ governed by the memory model in use, and the reentrancy options.
\end_layout
\begin_layout Standard
-Interrupts
-\begin_inset LatexCommand \index{interrupt}
+It is however allowed to use bit parameters in reentrant functions and also
+ non-static local bit variables are supported.
+ Efficient use is limited to 8 semi-bitregisters in bit space.
+ They are pushed and popped to stack
+\begin_inset LatexCommand \index{stack}
\end_inset
- can also be disabled and enabled directly (8051):
+ as a single byte just like the normal registers.
\end_layout
-\begin_layout Verse
-
-\family typewriter
+\begin_layout Section
+Overlaying
+\begin_inset LatexCommand \label{sub:Overlaying}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Overlaying}
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+For non-reentrant
+\begin_inset LatexCommand \index{reentrant}
+
+\end_inset
+
+ functions SDCC will try to reduce internal ram space usage by overlaying
+ parameters and local variables of a function (if possible).
+ Parameters and local variables
+\begin_inset LatexCommand \index{local variables}
+
+\end_inset
+
+ of a function will be allocated to an overlayable segment if the function
+ has
+\emph on
+no other function calls and the function is non-reentrant and the memory
+ model
+\begin_inset LatexCommand \index{Memory model}
+
+\end_inset
+
+ is small.
+
+\emph default
+ If an explicit storage class
+\begin_inset LatexCommand \index{Storage class}
+
+\end_inset
+
+ is specified for a local variable, it will NOT be overlayed.
+\end_layout
+
+\begin_layout Standard
+Note that the compiler (not the linkage editor) makes the decision for overlayin
+g the data items.
+ Functions that are called from an interrupt service routine
+\begin_inset Marginal
+status collapsed
+
+\begin_layout Standard
+
+\series bold
+!
+\end_layout
+
+\end_inset
+
+ should be preceded by a #pragma\InsetSpace ~
+nooverlay
+\begin_inset LatexCommand \index{\#pragma nooverlay}
+
+\end_inset
+
+ if they are not reentrant.
+\end_layout
+
+\begin_layout Standard
+Also note that the compiler does not do any processing of inline assembler
+ code, so the compiler might incorrectly assign local variables and parameters
+ of a function into the overlay segment if the inline assembler code calls
+ other c-functions that might use the overlay.
+ In that case the #pragma\InsetSpace ~
+nooverlay should be used.
+\end_layout
+
+\begin_layout Standard
+Parameters and local variables of functions that contain 16 or 32 bit multiplica
+tion
+\begin_inset LatexCommand \index{Multiplication}
+
+\end_inset
+
+ or division
+\begin_inset LatexCommand \index{Division}
+
+\end_inset
+
+ will NOT be overlayed since these are implemented using external functions,
+ e.g.:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+#pragma save
+\newline
+#pragma nooverlay
+\begin_inset LatexCommand \index{\#pragma nooverlay}
+
+\end_inset
+
+
+\newline
+void set_error(unsigned char errcd)
+\newline
+{
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+P3 = errcd;
+\newline
+}
+\newline
+#pragma restore
+\newline
+
+\newline
+void
+ some_isr () __interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ (2)
+\newline
+{
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+...
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+set_error(10);
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+...
+
+\newline
+}
+\end_layout
+
+\begin_layout Standard
+In the above example the parameter
+\emph on
+errcd
+\emph default
+ for the function
+\emph on
+set_error
+\emph default
+ would be assigned to the overlayable segment if the #pragma\InsetSpace ~
+nooverlay was
+ not present, this could cause unpredictable runtime behavior when called
+ from an interrupt service routine.
+ The #pragma\InsetSpace ~
+nooverlay ensures that the parameters and local variables for
+ the function are NOT overlayed.
+\begin_inset VSpace bigskip
+\end_inset
+
+
+\end_layout
+
+\begin_layout Section
+Interrupt Service Routines
+\begin_inset LatexCommand \label{sub:Interrupt-Service-Routines}
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+General Information
+\end_layout
+
+\begin_layout Standard
+SDCC allows
+\emph on
+i
+\emph default
+nterrupt
+\emph on
+s
+\emph default
+ervice
+\emph on
+r
+\emph default
+outines to be coded in C, with some extended keywords.
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+void timer_isr (void) __interrupt (1) __using (1)
+\newline
+{
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+...
+
+\newline
+}
+\end_layout
+
+\begin_layout Standard
+The optional number following the
+\emph on
+interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{\_\_interrupt}
+
+\end_inset
+
+
+\emph default
+ keyword is the interrupt number this routine will service.
+ When present, the compiler will insert a call to this routine in the interrupt
+ vector table
+\begin_inset LatexCommand \index{interrupt vector table}
+
+\end_inset
+
+ for the interrupt number specified.
+ If you have multiple source files in your project, interrupt service routines
+ can be present in any of them, but a prototype of the isr MUST be present
+ or included in the file that contains the function
+\emph on
+main
+\emph default
+.
+ The optional (8051 specific) keyword
+\emph on
+using
+\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
+
+\end_inset
+
+
+\emph default
+ can be used to tell the compiler to use the specified register bank when
+ generating code for this function.
+
+\newline
+Interrupt service routines open the door for some very interesting bugs:
+\end_layout
+
+\begin_layout Subsubsection
+\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-volatile}
+
+\end_inset
+
+Common interrupt pitfall: variable not declared
+\emph on
+volatile
+\end_layout
+
+\begin_layout Standard
+If an interrupt service routine changes variables which are accessed by
+ other functions these variables have to be declared
+\emph on
+volatile
+\emph default
+
+\begin_inset LatexCommand \index{volatile}
+
+\end_inset
+
+.
+ See
+\begin_inset LatexCommand \url{http://en.wikipedia.org/wiki/Volatile_variable}
+
+\end_inset
+
+ .
+\end_layout
+
+\begin_layout Subsubsection
+\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-atomic}
+
+\end_inset
+
+Common interrupt pitfall:
+\emph on
+non-atomic access
+\end_layout
+
+\begin_layout Standard
+If the access to these variables is not
+\emph on
+atomic
+\begin_inset LatexCommand \index{atomic}
+
+\end_inset
+
+
+\emph default
+ (i.e.
+ the processor needs more than one instruction for the access and could
+ be interrupted while accessing the variable) the interrupt must be disabled
+ during the access to avoid inconsistent data.
+
+\newline
+Access to 16 or 32 bit variables is obviously not atomic on 8 bit CPUs
+ and should be protected by disabling interrupts.
+ You're not automatically on the safe side if you use 8 bit variables though.
+ We need an example here: f.e.
+ on the 8051 the harmless looking
+\begin_inset Quotes srd
+\end_inset
+
+
+\family typewriter
+flags\InsetSpace ~
+|=\InsetSpace ~
+0x80;
+\family default
+
+\begin_inset Quotes sld
+\end_inset
+
+ is not atomic if
+\family typewriter
+flags
+\family default
+ resides in xdata.
+ Setting
+\begin_inset Quotes srd
+\end_inset
+
+
+\family typewriter
+flags\InsetSpace ~
+|=\InsetSpace ~
+0x40;
+\family default
+
+\begin_inset Quotes sld
+\end_inset
+
+ from within an interrupt routine might get lost if the interrupt occurs
+ at the wrong time.
+
+\begin_inset Quotes sld
+\end_inset
+
+
+\family typewriter
+counter\InsetSpace ~
++=\InsetSpace ~
+8;
+\family default
+
+\begin_inset Quotes srd
+\end_inset
+
+ is not atomic on the 8051 even if
+\family typewriter
+counter
+\family default
+ is located in data memory.
+\newline
+Bugs like these are hard to reproduce and can
+ cause a lot of trouble.
+
+\end_layout
+
+\begin_layout Subsubsection
+\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-stack-overflow}
+
+\end_inset
+
+Common interrupt pitfall:
+\emph on
+stack overflow
+\end_layout
+
+\begin_layout Standard
+The return address and the registers used in the interrupt service routine
+ are saved on the stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+ so there must be sufficient stack space.
+ If there isn't variables or registers (or even the return address itself)
+ will be corrupted.
+ This
+\emph on
+stack overflow
+\emph default
+
+\begin_inset LatexCommand \index{stack overflow}
+
+\end_inset
+
+ is most likely to happen if the interrupt occurs during the
+\begin_inset Quotes sld
+\end_inset
+
+deepest
+\begin_inset Quotes srd
+\end_inset
+
+ subroutine when the stack is already in use for f.e.
+ many return addresses.
+\end_layout
+
+\begin_layout Subsubsection
+\begin_inset LatexCommand \label{sub:Common-interrupt-pitfall-non-reentrant}
+
+\end_inset
+
+Common interrupt pitfall:
+\emph on
+use of non-reentrant functions
+\end_layout
+
+\begin_layout Standard
+A special note here, int (16 bit) and long (32 bit) integer division
+\begin_inset LatexCommand \index{Division}
+
+\end_inset
+
+, multiplication
+\begin_inset LatexCommand \index{Multiplication}
+
+\end_inset
+
+ & modulus
+\begin_inset LatexCommand \index{Modulus}
+
+\end_inset
+
+ and floating-point
+\begin_inset LatexCommand \index{Floating point support}
+
+\end_inset
+
+ operations are implemented using external support routines.
+ If an interrupt service routine needs to do any of these operations then
+ the support routines (as mentioned in a following section) will have to
+ be recompiled using the
+\emph on
+ -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-stack-auto
+\begin_inset LatexCommand \index{-\/-stack-auto}
+
+\end_inset
+
+
+\emph default
+ option and the source file will need to be compiled using the
+\emph on
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-int-long-reent
+\emph default
+
+\begin_inset LatexCommand \index{-\/-int-long-reent}
+
+\end_inset
+
+ compiler option.
+
+\newline
+Note, the type promotion
+\begin_inset LatexCommand \index{type promotion}
+
+\end_inset
+
+ required by ANSI C can cause 16 bit routines to be used
+\begin_inset Marginal
+status collapsed
+
+\begin_layout Standard
+
+\series bold
+\InsetSpace ~
+!
+\end_layout
+
+\end_inset
+
+ without the programmer being aware of it.
+ See f.e.
+ the cast
+\family typewriter
+(unsigned char)(tail-1)
+\family default
+ within the if clause in section
+\begin_inset LatexCommand \ref{sub:A-Step-by Assembler Introduction}
+
+\end_inset
+
+.
+\end_layout
+
+\begin_layout Standard
+Calling other functions from an interrupt service routine is not recommended,
+ avoid it if possible.
+ Note that when some function is called from an interrupt service routine
+ it should be preceded by a #pragma\InsetSpace ~
+nooverlay
+\begin_inset LatexCommand \index{\#pragma nooverlay}
+
+\end_inset
+
+ if it is not reentrant.
+ Furthermore nonreentrant functions should not be called from the main program
+ while the interrupt service routine might be active.
+ They also must not be called from low priority interrupt service routines
+ while a high priority interrupt service routine might be active.
+ You could use semaphores or make the function
+\emph on
+ critical
+\emph default
+ if all parameters are passed in registers.
+\newline
+ Also see section
+\begin_inset LatexCommand \ref{sub:Overlaying}
+
+\end_inset
+
+\InsetSpace ~
+about Overlaying and section
+\begin_inset LatexCommand \ref{sub:Functions-using-private-banks}
+
+\end_inset
+
+\InsetSpace ~
+about Functions using private register banks.
+\begin_inset VSpace bigskip
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+MCS51/DS390 Interrupt Service Routines
+\end_layout
+
+\begin_layout Standard
+Interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ numbers and the corresponding address & descriptions for the Standard 8051/8052
+ are listed below.
+ SDCC will automatically adjust the
+\begin_inset LatexCommand \index{interrupt vector table}
+
+\end_inset
+
+ to the maximum interrupt number specified.
+\newline
+
+\end_layout
+
+\begin_layout Standard
+\align center
+\begin_inset Tabular
+<lyxtabular version="3" rows="9" columns="3">
+<features>
+<column alignment="center" valignment="top" leftline="true" width="0in">
+<column alignment="left" valignment="top" leftline="true" width="0in">
+<column alignment="left" valignment="top" leftline="true" rightline="true" width="0in">
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Interrupt #
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Description
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Vector Address
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+External 0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x0003
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Timer 0
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x000b
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+2
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+External 1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x0013
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+3
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Timer 1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x001b
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+4
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Serial
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x0023
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell multicolumn="1" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+5
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Timer 2 (8052)
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x002b
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+...
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+...
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+n
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0x0003 + 8*n
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\newline
+
+\end_layout
+
+\begin_layout Standard
+If the interrupt service routine is defined without
+\emph on
+using
+\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
+
+\end_inset
+
+
+\emph default
+ a register bank or with register bank 0 (
+\emph on
+using
+\emph default
+ 0), the compiler will save the registers used by itself on the stack upon
+ entry and restore them at exit, however if such an interrupt service routine
+ calls another function then the entire register bank will be saved on the
+ stack.
+ This scheme may be advantageous for small interrupt service routines which
+ have low register usage.
+\end_layout
+
+\begin_layout Standard
+If the interrupt service routine is defined to be using a specific register
+ bank then only
+\emph on
+a, b, dptr
+\emph default
+ & psw are saved and restored, if such an interrupt service routine calls
+ another function (using another register bank) then the entire register
+ bank of the called function will be saved on the stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+.
+ This scheme is recommended for larger interrupt service routines.
+\begin_inset VSpace bigskip
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+HC08
+\begin_inset LatexCommand \index{HC08}
+
+\end_inset
+
+ Interrupt Service Routines
+\end_layout
+
+\begin_layout Standard
+Since the number of interrupts
+\begin_inset LatexCommand \index{HC08!interrupt}
+
+\end_inset
+
+ available is chip specific and the interrupt vector table always ends at
+ the last byte of memory, the interrupt numbers corresponds to the interrupt
+ vectors in reverse order of address.
+ For example, interrupt 1 will use the interrupt vector at 0xfffc, interrupt
+ 2 will use the interrupt vector at 0xfffa, and so on.
+ However, interrupt 0 (the reset vector at 0xfffe) is not redefinable in
+ this way; instead see section
+\begin_inset LatexCommand \ref{sub:Startup-Code}
+
+\end_inset
+
+ for details on customizing startup.
+\begin_inset VSpace bigskip
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+Z80 Interrupt Service Routines
+\end_layout
+
+\begin_layout Standard
+The Z80
+\begin_inset LatexCommand \index{Z80}
+
+\end_inset
+
+ uses several different methods for determining the correct interrupt
+\begin_inset LatexCommand \index{Z80!interrupt}
+
+\end_inset
+
+ vector depending on the hardware implementation.
+ Therefore, SDCC ignores the optional interrupt number and does not attempt
+ to generate an interrupt vector table.
+\end_layout
+
+\begin_layout Standard
+By default, SDCC generates code for a maskable interrupt, which uses a RETI
+ instruction to return from the interrupt.
+ To write an interrupt handler for the non-maskable interrupt, which needs
+ a RETN instruction instead, add the
+\emph on
+critical
+\emph default
+ keyword:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+void nmi_isr (void) critical interrupt
+\newline
+{
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+...
+
+\newline
+}
+\end_layout
+
+\begin_layout Standard
+However if you need to create a non-interruptable interrupt service routine
+ you would also require the
+\emph on
+critical
+\emph default
+ keyword.
+ To distinguish between this and an nmi_isr you must provide an interrupt
+ number.
+\begin_inset VSpace bigskip
+\end_inset
+
+
+\end_layout
+
+\begin_layout Section
+Enabling and Disabling Interrupts
+\end_layout
+
+\begin_layout Subsection
+Critical Functions and Critical Statements
+\end_layout
+
+\begin_layout Standard
+A special keyword may be associated with a block or a function declaring
+ it as
+\emph on
+critical
+\emph default
+.
+ SDCC will generate code to disable all interrupts
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ upon entry to a critical function and restore the interrupt enable to the
+ previous state before returning.
+ Nesting critical functions will need one additional byte on the stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+ for each call.
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+int foo () __critical
+\begin_inset LatexCommand \index{critical}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{\_\_critical}
+
+\end_inset
+
+
+\newline
+{
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+...
+
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+...
+
+\newline
+}
+\end_layout
+
+\begin_layout Standard
+The critical attribute maybe used with other attributes like
+\emph on
+reentrant.
+\emph default
+
+\newline
+The keyword
+\emph on
+critical
+\emph default
+ may also be used to disable interrupts more locally:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+__critical{ i++; }
+\end_layout
+
+\begin_layout Standard
+More than one statement could have been included in the block.
+\end_layout
+
+\begin_layout Subsection
+Enabling and Disabling Interrupts directly
+\end_layout
+
+\begin_layout Standard
+Interrupts
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ can also be disabled and enabled directly (8051):
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
EA = 0;\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-or:\InsetSpace ~
+or:\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+EA_SAVE = EA;
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+...\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+EA = 0;
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+EA = 1;\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+...
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+EA = EA_SAVE;
+\end_layout
+
+\begin_layout Standard
+On other architectures which have seperate opcodes for enabling and disabling
+ interrupts you might want to make use of defines with inline assembly
+\begin_inset LatexCommand \index{Assembler routines}
+
+\end_inset
+
+ (HC08
+\begin_inset LatexCommand \index{HC08!interrupt}
+
+\end_inset
+
+):
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+#define CLI _asm
+\begin_inset LatexCommand \index{\_asm}
+
+\end_inset
+
+\InsetSpace ~
+\InsetSpace ~
+cli\InsetSpace ~
+\InsetSpace ~
+_endasm
+\begin_inset LatexCommand \index{\_endasm}
+
+\end_inset
+
+;
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+#define SEI _asm\InsetSpace ~
+\InsetSpace ~
+sei\InsetSpace ~
+\InsetSpace ~
+_endasm;
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+...
+\end_layout
+
+\begin_layout Standard
+Note: it is sometimes sufficient to disable only a specific interrupt source
+ like f.e.
+ a timer or serial interrupt by manipulating an
+\emph on
+interrupt mask
+\begin_inset LatexCommand \index{interrupt mask}
+
+\end_inset
+
+
+\emph default
+ register.
+
+\end_layout
+
+\begin_layout Standard
+Usually the time during which interrupts are disabled should be kept as
+ short as possible.
+ This minimizes both
+\emph on
+interrupt latency
+\emph default
+
+\begin_inset LatexCommand \index{interrupt latency}
+
+\end_inset
+
+ (the time between the occurrence of the interrupt and the execution of
+ the first code in the interrupt routine) and
+\emph on
+interrupt jitter
+\emph default
+
+\begin_inset LatexCommand \index{interrupt jitter}
+
+\end_inset
+
+ (the difference between the shortest and the longest interrupt latency).
+ These really are something different, f.e.
+ a serial interrupt has to be served before its buffer overruns so it cares
+ for the maximum interrupt latency, whereas it does not care about jitter.
+ On a loudspeaker driven via a digital to analog converter which is fed
+ by an interrupt a latency of a few milliseconds might be tolerable, whereas
+ a much smaller jitter will be very audible.
+\end_layout
+
+\begin_layout Standard
+You can reenable interrupts within an interrupt routine and on some architecture
+s you can make use of two (or more) levels of
+\emph on
+interrupt priorities
+\emph default
+
+\begin_inset LatexCommand \index{interrupt priority}
+
+\end_inset
+
+.
+ On some architectures which don't support interrupt priorities these can
+ be implemented by manipulating the interrupt mask and reenabling interrupts
+ within the interrupt routine.
+ Check there is sufficient space on the stack
+\begin_inset LatexCommand \index{stack}
+
+\end_inset
+
+ and don't add complexity unless you have to.
+
+\end_layout
+
+\begin_layout Subsection
+Semaphore
+\begin_inset LatexCommand \index{semaphore}
+
+\end_inset
+
+ locking (mcs51/ds390)
+\end_layout
+
+\begin_layout Standard
+Some architectures (mcs51/ds390) have an atomic
+\begin_inset LatexCommand \index{atomic}
+
+\end_inset
+
+ bit test and
+\emph on
+
+\emph default
+clear
+\emph on
+
+\emph default
+instruction.
+ These type of instructions are typically used in preemptive multitasking
+ systems, where a routine f.e.
+ claims the use of a data structure ('acquires a lock
+\begin_inset LatexCommand \index{lock}
+
+\end_inset
+
+ on it'), makes some modifications and then releases the lock when the data
+ structure is consistent again.
+ The instruction may also be used if interrupt and non-interrupt code have
+ to compete for a resource.
+ With the atomic bit test and clear instruction interrupts
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+ don't have to be disabled for the locking operation.
+
+\end_layout
+
+\begin_layout Standard
+SDCC generates this instruction if the source follows this pattern:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+volatile
+\begin_inset LatexCommand \index{volatile}
+
+\end_inset
+
+ bit resource_is_free;
+\newline
+
+\newline
+if (resource_is_free)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+{
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+resource_is_free=0;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+...
+
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+resource_is_free=1;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+}
+\end_layout
+
+\begin_layout Standard
+Note, mcs51 and ds390 support only an atomic
+\begin_inset LatexCommand \index{atomic}
+
+\end_inset
+
+ bit test and
+\emph on
+clear
+\emph default
+ instruction (as opposed to atomic bit test and
+\emph on
+set).
+\end_layout
+
+\begin_layout Section
+Functions using private register banks
+\begin_inset LatexCommand \label{sub:Functions-using-private-banks}
+
+\end_inset
+
+ (mcs51/ds390)
+\end_layout
+
+\begin_layout Standard
+Some architectures have support for quickly changing register sets.
+ SDCC supports this feature with the
+\emph on
+using
+\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
+
+\end_inset
+
+
+\emph default
+ attribute (which tells the compiler to use a register bank
+\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
+
+\end_inset
+
+ other than the default bank zero).
+ It should only be applied to
+\emph on
+interrupt
+\begin_inset LatexCommand \index{interrupt}
+
+\end_inset
+
+
+\emph default
+ functions (see footnote below).
+ This will in most circumstances make the generated ISR code more efficient
+ since it will not have to save registers on the stack.
+\end_layout
+
+\begin_layout Standard
+The
+\emph on
+using
+\emph default
+ attribute will have no effect on the generated code for a
+\emph on
+non-interrupt
+\emph default
+ function (but may occasionally be useful anyway
+\begin_inset Foot
+status open
+
+\begin_layout Standard
+possible exception: if a function is called ONLY from 'interrupt' functions
+ using a particular bank, it can be declared with the same 'using' attribute
+ as the calling 'interrupt' functions.
+ For instance, if you have several ISRs using bank one, and all of them
+ call memcpy(), it might make sense to create a specialized version of memcpy()
+ 'using 1', since this would prevent the ISR from having to save bank zero
+ to the stack on entry and switch to bank zero before calling the function
+\end_layout
+
+\end_inset
+
+).
+\newline
+
+\emph on
+(pending: Note, nowadays the
+\emph default
+using
+\emph on
+ attribute has an effect on
+\emph default
+
+\emph on
+the generated code for a
+\emph default
+non-interrupt
+\emph on
+ function
+\emph default
+.
+\emph on
+)
+\end_layout
+
+\begin_layout Standard
+An
+\emph on
+interrupt
+\emph default
+ function using a non-zero bank will assume that it can trash that register
+ bank, and will not save it.
+ Since high-priority interrupts
+\begin_inset LatexCommand \index{interrupts}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{interrupt priority}
+
+\end_inset
+
+ can interrupt low-priority ones on the 8051 and friends, this means that
+ if a high-priority ISR
+\emph on
+using
+\emph default
+ a particular bank occurs while processing a low-priority ISR
+\emph on
+using
+\emph default
+ the same bank, terrible and bad things can happen.
+ To prevent this, no single register bank should be
+\emph on
+used
+\emph default
+ by both a high priority and a low priority ISR.
+ This is probably most easily done by having all high priority ISRs use
+ one bank and all low priority ISRs use another.
+ If you have an ISR which can change priority at runtime, you're on your
+ own: I suggest using the default bank zero and taking the small performance
+ hit.
+\end_layout
+
+\begin_layout Standard
+It is most efficient if your ISR calls no other functions.
+ If your ISR must call other functions, it is most efficient if those functions
+ use the same bank as the ISR (see note 1 below); the next best is if the
+ called functions use bank zero.
+ It is very inefficient to call a function using a different, non-zero bank
+ from an ISR.
+
+\begin_inset VSpace bigskip
+\end_inset
+
+
+\end_layout
+
+\begin_layout Section
+Startup Code
+\begin_inset LatexCommand \label{sub:Startup-Code}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{Startup code}
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Subsection
+MCS51/DS390 Startup Code
+\end_layout
+
+\begin_layout Standard
+The compiler triggers the linker to link certain initialization modules
+ from the runtime library
+\begin_inset LatexCommand \index{Runtime library}
+
+\end_inset
+
+ called crt<something>.
+ Only the necessary ones are linked, for instance crtxstack.asm (GSINIT1,
+ GSINIT5) is not linked unless the -
+\series bold
+
+\begin_inset ERT
+status open
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+
+\series default
+-xstack option is used.
+ These modules are highly entangled by the use of special segments/areas,
+ but a common layout is shown below:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\series bold
+\size footnotesize
+(main.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+.area HOME (CODE)
+\newline
+__interrupt_vect:
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+ljmp __sdcc_gsinit_startup
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\series bold
+\size footnotesize
+(crtstart.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+.area GSINIT0 (CODE)
+\newline
+__sdcc_gsinit_startup::
+\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-EA_SAVE = EA;
+\InsetSpace ~
+mov sp,#__start__stack - 1
\end_layout
\begin_layout Verse
\family typewriter
-...\InsetSpace ~
+\series bold
+\size footnotesize
+(crtxstack.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+.area GSINIT1 (CODE)
+\newline
+__sdcc_init_xstack::
+\newline
+; Need to initialize in GSINIT1 in
+ case the user's __sdcc_external_startup uses the xstack.
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov __XPAGE,#(__start__x
+stack >> 8)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov _spx,#__start__xstack
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\series bold
+\size footnotesize
+(crtstart.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+.area GSINIT2 (CODE)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+lcall __sdcc_external_startup
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov a,dpl
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+jz __sdcc_init_data
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+ljmp
+ __sdcc_program_startup
+\newline
+__sdcc_init_data:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\series bold
+\size footnotesize
+(crtxinit.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+.area GSINIT3 (CODE)
+\newline
+__mcs51_genXINIT::
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov r1,#l_XINIT
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov a,r1
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+orl a,#(l_XINIT
+ >> 8)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+jz 00003$
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov r2,#((l_XINIT+255) >> 8)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov dptr,#s_XINIT
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov r0,#s_XISEG
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov
+ __XPAGE,#(s_XISEG >> 8)
+\newline
+00001$:\InsetSpace ~
+clr a
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+movc a,@a+dptr
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+movx @r0,a
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+inc dptr
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+inc
+ r0
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+cjne r0,#0,00002$
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+inc __XPAGE
+\newline
+00002$:\InsetSpace ~
+djnz r1,00001$
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+djnz r2,00001$
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov __XPAGE,#0
+xFF
+\newline
+00003$:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\series bold
+\size footnotesize
+(crtclear.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+.area GSINIT4 (CODE)
+\newline
+__mcs51_genRAMCLEAR::
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+clr a
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov r0,#(l_IRAM-1)
+\newline
+00004$:\InsetSpace ~
+mov
+ @r0,a
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+djnz r0,00004$
+\newline
+; _mcs51_genRAMCLEAR() end
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\series bold
+\size footnotesize
+(crtxclear.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+.area GSINIT4 (CODE)
+\newline
+__mcs51_genXRAMCLEAR::
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov r0,#l_PSEG
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov a,r0
+\newline
+\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+orl a,#(l_PSEG
+ >> 8)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+jz 00006$
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov r1,#s_PSEG
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov __XPAGE,#(s_PSEG >> 8)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+clr a
+\newline
+00005$:\InsetSpace ~
+movx
+ @r1,a
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+inc r1
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+djnz r0,00005$
+\newline
+00006$:
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov r0,#l_XSEG
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov a,r0
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+orl a,#(l_XSEG >>
+ 8)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+jz 00008$
+\newline
+\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+mov r1,#((l_XSEG + 255) >> 8)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov dptr,#s_XSEG
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+clr a
+\newline
+00007$:\InsetSpace ~
+movx
+ @dptr,a
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+inc dptr
+\newline
+\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+djnz r0,00007$
+\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-EA = 0;
+djnz r1,00007$
+\newline
+00008$:
\end_layout
\begin_layout Verse
\family typewriter
-EA = 1;\InsetSpace ~
-\InsetSpace ~
+\series bold
+\size footnotesize
+(crtxstack.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+.area GSINIT5 (CODE)
+\newline
+; Need to initialize in GSINIT5 because __mcs51_genXINIT
+ modifies __XPAGE
+\newline
+; and __mcs51_genRAMCLEAR modifies _spx.
+\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+mov __XPAGE,#(__start__x
+stack >> 8)
+\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-...
+mov _spx,#__start__xstack
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\series bold
+\size footnotesize
+(application modules)
\end_layout
\begin_layout Verse
\family typewriter
+\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+.area GSINIT (CODE)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\series bold
+\size footnotesize
+(main.asm)
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+\size footnotesize
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+.area GSFINAL (CODE)
+\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+ljmp __sdcc_program_startup
+\newline
+;---------------------------------
+-----------------------
+\newline
+; Home
+\newline
+;--------------------------------------------------
+------
+\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
+.area HOME (CODE)
+\newline
\InsetSpace ~
-EA = EA_SAVE;
-\end_layout
-
-\begin_layout Standard
-On other architectures which have seperate opcodes for enabling and disabling
- interrupts you might want to make use of defines with inline assembly
-\begin_inset LatexCommand \index{Assembler routines}
-
-\end_inset
-
- (HC08
-\begin_inset LatexCommand \index{HC08!interrupt}
-
-\end_inset
-
-):
-\end_layout
-
-\begin_layout Verse
-
-\family typewriter
-#define CLI _asm
-\begin_inset LatexCommand \index{\_asm}
-
-\end_inset
-
\InsetSpace ~
\InsetSpace ~
-cli\InsetSpace ~
\InsetSpace ~
-_endasm
-\begin_inset LatexCommand \index{\_endasm}
-
-\end_inset
-
-;
-\end_layout
-
-\begin_layout Verse
-
-\family typewriter
-#define SEI _asm\InsetSpace ~
\InsetSpace ~
-sei\InsetSpace ~
\InsetSpace ~
-_endasm;
-\end_layout
-
-\begin_layout Verse
-
-\family typewriter
-...
-\end_layout
-
-\begin_layout Standard
-Note: it is sometimes sufficient to disable only a specific interrupt source
- like f.e.
- a timer or serial interrupt by manipulating an
-\emph on
-interrupt mask
-\begin_inset LatexCommand \index{interrupt mask}
-
-\end_inset
-
-
-\emph default
- register.
-
-\end_layout
-
-\begin_layout Standard
-Usually the time during which interrupts are disabled should be kept as
- short as possible.
- This minimizes both
-\emph on
-interrupt latency
-\emph default
-
-\begin_inset LatexCommand \index{interrupt latency}
-
-\end_inset
-
- (the time between the occurrence of the interrupt and the execution of
- the first code in the interrupt routine) and
-\emph on
-interrupt jitter
-\emph default
-
-\begin_inset LatexCommand \index{interrupt jitter}
-
-\end_inset
-
- (the difference between the shortest and the longest interrupt latency).
- These really are something different, f.e.
- a serial interrupt has to be served before its buffer overruns so it cares
- for the maximum interrupt latency, whereas it does not care about jitter.
- On a loudspeaker driven via a digital to analog converter which is fed
- by an interrupt a latency of a few milliseconds might be tolerable, whereas
- a much smaller jitter will be very audible.
-\end_layout
-
-\begin_layout Standard
-You can reenable interrupts within an interrupt routine and on some architecture
-s you can make use of two (or more) levels of
-\emph on
-interrupt priorities
-\emph default
-
-\begin_inset LatexCommand \index{interrupt priority}
-
-\end_inset
-
-.
- On some architectures which don't support interrupt priorities these can
- be implemented by manipulating the interrupt mask and reenabling interrupts
- within the interrupt routine.
- Check there is sufficient space on the stack
-\begin_inset LatexCommand \index{stack}
-
-\end_inset
-
- and don't add complexity unless you have to.
-
-\end_layout
-
-\begin_layout Subsection
-Semaphore
-\begin_inset LatexCommand \index{semaphore}
-
-\end_inset
-
- locking (mcs51/ds390)
-\end_layout
-
-\begin_layout Standard
-Some architectures (mcs51/ds390) have an atomic
-\begin_inset LatexCommand \index{atomic}
-
-\end_inset
-
- bit test and
-\emph on
-
-\emph default
-clear
-\emph on
-
-\emph default
-instruction.
- These type of instructions are typically used in preemptive multitasking
- systems, where a routine f.e.
- claims the use of a data structure ('acquires a lock
-\begin_inset LatexCommand \index{lock}
-
-\end_inset
-
- on it'), makes some modifications and then releases the lock when the data
- structure is consistent again.
- The instruction may also be used if interrupt and non-interrupt code have
- to compete for a resource.
- With the atomic bit test and clear instruction interrupts
-\begin_inset LatexCommand \index{interrupt}
-
-\end_inset
-
- don't have to be disabled for the locking operation.
-
-\end_layout
-
-\begin_layout Standard
-SDCC generates this instruction if the source follows this pattern:
-\end_layout
-
-\begin_layout Verse
-
-\family typewriter
-volatile
-\begin_inset LatexCommand \index{volatile}
-
-\end_inset
-
- bit resource_is_free;
-\newline
-
-\newline
-if (resource_is_free)
-\newline
\InsetSpace ~
\InsetSpace ~
-{
+.area CSEG (CODE)
+\newline
+__sdcc_program_startup:
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-resource_is_free=0;
-\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-...
-
+lcall _main
+\newline
+;
+ return from main will lock up
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-resource_is_free=1;
-\newline
\InsetSpace ~
\InsetSpace ~
-}
-\end_layout
-
-\begin_layout Standard
-Note, mcs51 and ds390 support only an atomic
-\begin_inset LatexCommand \index{atomic}
-
-\end_inset
-
- bit test and
-\emph on
-clear
-\emph default
- instruction (as opposed to atomic bit test and
-\emph on
-set).
-\end_layout
-
-\begin_layout Section
-Functions using private register banks
-\begin_inset LatexCommand \label{sub:Functions-using-private-banks}
-
-\end_inset
-
- (mcs51/ds390)
-\end_layout
-
-\begin_layout Standard
-Some architectures have support for quickly changing register sets.
- SDCC supports this feature with the
-\emph on
-using
-\begin_inset LatexCommand \index{using (mcs51, ds390 register bank)}
-
-\end_inset
-
-
-\begin_inset LatexCommand \index{\_\_using (mcs51, ds390 register bank)}
-
-\end_inset
-
-
-\emph default
- attribute (which tells the compiler to use a register bank
-\begin_inset LatexCommand \index{register bank (mcs51, ds390)}
-
-\end_inset
-
- other than the default bank zero).
- It should only be applied to
-\emph on
-interrupt
-\begin_inset LatexCommand \index{interrupt}
-
-\end_inset
-
-
-\emph default
- functions (see footnote below).
- This will in most circumstances make the generated ISR code more efficient
- since it will not have to save registers on the stack.
-\end_layout
-
-\begin_layout Standard
-The
-\emph on
-using
-\emph default
- attribute will have no effect on the generated code for a
-\emph on
-non-interrupt
-\emph default
- function (but may occasionally be useful anyway
-\begin_inset Foot
-status open
-
-\begin_layout Standard
-possible exception: if a function is called ONLY from 'interrupt' functions
- using a particular bank, it can be declared with the same 'using' attribute
- as the calling 'interrupt' functions.
- For instance, if you have several ISRs using bank one, and all of them
- call memcpy(), it might make sense to create a specialized version of memcpy()
- 'using 1', since this would prevent the ISR from having to save bank zero
- to the stack on entry and switch to bank zero before calling the function
-\end_layout
-
-\end_inset
-
-).
-\newline
-
-\emph on
-(pending: Note, nowadays the
-\emph default
-using
-\emph on
- attribute has an effect on
-\emph default
-
-\emph on
-the generated code for a
-\emph default
-non-interrupt
-\emph on
- function
-\emph default
-.
-\emph on
-)
-\end_layout
-
-\begin_layout Standard
-An
-\emph on
-interrupt
-\emph default
- function using a non-zero bank will assume that it can trash that register
- bank, and will not save it.
- Since high-priority interrupts
-\begin_inset LatexCommand \index{interrupts}
-
-\end_inset
-
-
-\begin_inset LatexCommand \index{interrupt priority}
-
-\end_inset
-
- can interrupt low-priority ones on the 8051 and friends, this means that
- if a high-priority ISR
-\emph on
-using
-\emph default
- a particular bank occurs while processing a low-priority ISR
-\emph on
-using
-\emph default
- the same bank, terrible and bad things can happen.
- To prevent this, no single register bank should be
-\emph on
-used
-\emph default
- by both a high priority and a low priority ISR.
- This is probably most easily done by having all high priority ISRs use
- one bank and all low priority ISRs use another.
- If you have an ISR which can change priority at runtime, you're on your
- own: I suggest using the default bank zero and taking the small performance
- hit.
-\end_layout
-
-\begin_layout Standard
-It is most efficient if your ISR calls no other functions.
- If your ISR must call other functions, it is most efficient if those functions
- use the same bank as the ISR (see note 1 below); the next best is if the
- called functions use bank zero.
- It is very inefficient to call a function using a different, non-zero bank
- from an ISR.
-
-\begin_inset VSpace bigskip
-\end_inset
-
-
-\end_layout
-
-\begin_layout Section
-Startup Code
-\begin_inset LatexCommand \label{sub:Startup-Code}
-
-\end_inset
-
-
-\begin_inset LatexCommand \index{Startup code}
-
-\end_inset
-
-
-\end_layout
-
-\begin_layout Subsection
-MCS51/DS390 Startup Code
+\InsetSpace ~
+\InsetSpace ~
+sjmp .
\end_layout
\begin_layout Standard
-The compiler inserts a call to the C routine
+One of these modules (crtstart.asm) contains a call to the C routine
\emph on
_sdcc_external_startup()
\begin_inset LatexCommand \index{\_sdcc\_external\_startup()}
\series default
at the start of the CODE area.
- This routine is in the runtime library
+ This routine is also in the runtime library
\begin_inset LatexCommand \index{Runtime library}
\end_inset
-.
- By default this routine returns 0, if this routine returns a non-zero value,
- the static & global variable initialization will be skipped and the function
- main will be invoked.
+ and returns 0 by default.
+ If this routine returns a non-zero value, the static & global variable
+ initialization will be skipped and the function main will be invoked.
Otherwise static & global variables will be initialized before the function
main is invoked.
- You could add a
+ You could add an
\emph on
_sdcc_external_startup()
\emph default
\end_inset
about MCS51-variants.
+\newline
+
+\end_layout
+
+\begin_layout Standard
+While these initialization modules are meant as generic startup code there
+ might be the need for customization.
+ Let's assume the return value of
+\emph on
+_sdcc_external_startup()
+\emph default
+ in
+\emph on
+crtstart.asm
+\emph default
+ should not be checked (or
+\emph on
+_sdcc_external_startup()
+\emph default
+ should not be called at all).
+ The recommended way would be to copy
+\emph on
+crtstart.asm
+\emph default
+ (f.e.
+ from
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/device/lib/mcs51/crtstart.asm}
+
+\end_inset
+
+) into the source directory, adapt it there, then assemble it with
+\emph on
+asx8051 -plosgff
+\begin_inset Foot
+status open
+
+\begin_layout Standard
+\begin_inset Quotes sld
+\end_inset
+
+-plosgff
+\begin_inset Quotes srd
+\end_inset
+
+ are the assembler options used in
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/lib/mcs51/Makefile.in?view=markup }
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+
+ crtstart.asm
+\emph default
+ and when linking your project explicitely specify
+\emph on
+crtstart.rel
+\emph default
+.
+ As a bonus a listing of the relocated object file
+\emph on
+crtstart.rst
+\emph default
+ is generated.
+\end_layout
+
+\begin_layout Standard
\begin_inset VSpace bigskip
\end_inset
\begin_inset Quotes sld
\end_inset
+
+\series bold
_asm
+\series default
+
\begin_inset Quotes srd
\end_inset
\begin_inset Quotes sld
\end_inset
+
+\series bold
_endasm;
+\series default
+
\begin_inset Quotes srd
+\end_inset
+
+
+\begin_inset Foot
+status open
+
+\begin_layout Standard
+Note, that the single underscore form (_asm and _endasm) are not C99-compatible,
+ and for C-99 compatibility, the double-underscore form (__asm and __endasm)
+ has to be used.
+ The latter is also used in the library functions.
+\end_layout
+
\end_inset
to the beginning and the end of the function body:
\end_inset
or online at
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
\end_inset
\begin_layout Standard
SDCC allows the use of in-line assembler with a few restrictions regarding
labels.
- In older versions of the compiler all labels defined within inline assembler
- code
-\emph on
-had to be
-\emph default
- of the form
+ All labels defined within inline assembler code have to be of the form
+
\emph on
nnnnn$
\emph default
- where nnnn is a number less than 100 (which implies a limit of utmost 100
- inline assembler labels
+ where nnnnn is a number less than 100 (which implies a limit of utmost
+ 100 inline assembler labels
\emph on
per function
\emph default
)
\noun default
.
+\begin_inset Foot
+status open
+
+\begin_layout Standard
+This is a slightly more stringent rule than absolutely necessary, but stays
+ always on the safe side.
+ Labels in the form of nnnnn$ are local labels in the assembler, locality
+ of which is confined within two labels of the standard form.
+ The compiler uses the same form for labels within a function (but starting
+ from nnnnn=00100); and places always a standard label at the beginning
+ of a function, thus limiting the locality of labels within the scope of
+ the function.
+ So, if the inline assembler part would be embedded into C-code, an improperly
+ placed non-local label in the assembler would break up the reference space
+ for labels created by the compiler for the C-code, leading to an assembling
+ error.
+\end_layout
+
+\begin_layout Standard
+The numeric part of local labels does not need to have 5 digits (although
+ this is the form of labels output by the compiler), any valid integer will
+ do.
+ Please refer to the assemblers documentation for further details.
+\end_layout
+
+\end_inset
+
\end_layout
\end_layout
\begin_layout Standard
-Inline assembler code cannot reference any C-Labels, however it can reference
+Inline assembler code cannot reference any C-labels, however it can reference
labels
\begin_inset LatexCommand \index{Labels}
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-ljmp $0003
+ljmp 0003$
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
/* inline assembler cannot reference this
label */
+\begin_inset Foot
+status open
+
+\begin_layout Standard
+Here, the C-label
+\family typewriter
+clabel
+\family default
+ is translated by the compiler into a local label, so the locality of labels
+ within the function is not broken.
+\end_layout
+
+\end_inset
+
+
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-$0003: ;label (can be referenced by inline assembler only)
-
+0003$: ;label (can be referenced by inline assembler only)
\newline
\InsetSpace ~
\InsetSpace ~
\emph default
- to pass the first parameter to a routine.
- The second parameter onwards is either allocated on the stack (for reentrant
+ to pass the first (non-bit) parameter to a function, and also to pass the
+ return value
+\begin_inset LatexCommand \index{return value}
+
+\end_inset
+
+of function; according to the following scheme: one byte return value in
+
+\emph on
+DPL
+\emph default
+, two byte value in
+\emph on
+DPL
+\emph default
+ (LSB) and
+\emph on
+DPH
+\emph default
+ (MSB).
+ three byte values (generic pointers) in
+\emph on
+DPH
+\emph default
+,
+\emph on
+DPL
+\emph default
+ and
+\emph on
+B
+\emph default
+, and four byte values in
+\emph on
+DPH
+\emph default
+,
+\emph on
+DPL
+\emph default
+,
+\emph on
+ B
+\emph default
+ and
+\emph on
+ACC
+\emph default
+.
+ Generic pointers
+\begin_inset LatexCommand \index{generic pointer}
+
+\end_inset
+
+ contain type of accessed memory in
+\emph on
+B
+\emph default
+:
+\series bold
+0x00
+\series default
+ -- xdata/far,
+\series bold
+0x40
+\series default
+ -- idata/near -- ,
+\series bold
+0x60
+\series default
+ -- pdata,
+\series bold
+0x80
+\series default
+ -- code
+\begin_inset Note Note
+status collapsed
+
+\begin_layout Standard
+This might not be the case of certain memory models (medium???)
+\end_layout
+
+\end_inset
+
+.
+\end_layout
+
+\begin_layout Standard
+The second parameter onwards is either allocated on the stack (for reentrant
routines or if -
\begin_inset ERT
status collapsed
\end_inset
--stack-auto is used) or in data / xdata memory (depending on the memory
- model).
+-stack-auto is used) or in data/xdata memory (depending on the memory model).
+\end_layout
+
+\begin_layout Standard
+Bit parameters are passed in a virtual register called 'bits' in bit-addressable
+ space for reentrant functions or allocated directly in bit memory otherwise.
+\end_layout
+
+\begin_layout Standard
+Functions (with two or more parameters or bit parameters) that are called
+ through function pointers
+\begin_inset LatexCommand \index{function pointers}
+
+\end_inset
+
+ must therefor be reentrant so the compiler knows how to pass the parameters.
+\end_layout
+
+\begin_layout Subsection
+Registers usage
+\end_layout
+
+\begin_layout Standard
+Unless the called function is declared as
+\family typewriter
+_naked
+\family default
+
+\begin_inset LatexCommand \index{naked}
+
+\end_inset
+
+, or the -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-callee-saves
+\begin_inset LatexCommand \index{-\/-callee-saves}
+
+\end_inset
+
+/-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-all-callee-saves command line option or the corresponding callee_saves
+ pragma are used, the caller will save the registers (
+\emph on
+R0-R7
+\emph default
+) around the call, so the called function can destroy they content freely.
+\end_layout
+
+\begin_layout Standard
+If the called function is not declared as
+\family typewriter
+_naked
+\family default
+, the caller will swap register banks around the call, if caller and callee
+ use different register banks (having them defined by the
+\family typewriter
+_using
+\family default
+ modifier).
\end_layout
+\begin_layout Standard
+The called function can also use
+\emph on
+DPL
+\emph default
+,
+\emph on
+DPH
+\emph default
+,
+\emph on
+B
+\emph default
+ and
+\emph on
+ACC
+\emph default
+ observing that they are used for parameter/return value passing.
+\end_layout
+
\begin_layout Subsection
Assembler Routine (non-reentrant)
\end_layout
ret
\end_layout
-\begin_layout Standard
-Note here that the return values
-\begin_inset LatexCommand \index{return value}
-
-\end_inset
-
- are placed in 'dpl' - One byte return value, 'dpl' LSB & 'dph' MSB for
- two byte values.
- 'dpl', 'dph' and 'b' for three byte values (generic pointers) and 'dpl','dph','
-b' & 'acc' for four byte values.
-\end_layout
-
\begin_layout Standard
The parameter naming convention is _<function_name>_PARM_<n>, where n is
the parameter number starting from 1, and counting from the left.
The first parameter is passed in
-\begin_inset Quotes eld
-\end_inset
-
-dpl
-\begin_inset Quotes erd
-\end_inset
-
- for a one byte parameter,
-\begin_inset Quotes eld
-\end_inset
-
-dptr
-\begin_inset Quotes erd
-\end_inset
-
- for two bytes,
-\begin_inset Quotes eld
-\end_inset
-
-b,dptr
-\begin_inset Quotes erd
-\end_inset
-
- for three bytes and
-\begin_inset Quotes eld
-\end_inset
-
-acc,b,dptr
-\begin_inset Quotes erd
-\end_inset
-
- for a four bytes parameter.
+\emph on
+DPH
+\emph default
+,
+\emph on
+DPL
+\emph default
+,
+\emph on
+B
+\emph default
+ and
+\emph on
+ACC
+\emph default
+ according to the description above.
The variable name for the second parameter will be _<function_name>_PARM_2.
\newline
onwards will be passed on the stack, the parameters are pushed from right
to left i.e.
- after the call the leftmost parameter will be on the top of the stack.
+ before the call the second leftmost parameter will be on the top of the
+ stack (the leftmost parameter is passed in registers).
Here is an example:
\end_layout
\begin_layout Verse
\family typewriter
-extern int asm_func(unsigned char, unsigned char);
+extern int asm_func(unsigned char, unsigned char, unsigned char) reentrant;
\newline
\newline
-int c_func (unsigned char
- i, unsigned char j) reentrant
+int
+ c_func (unsigned char i, unsigned char j, unsigned char k) reentrant
\newline
-{
+{
+
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-return asm_func(i,j);
+return asm_func(i,j,k);
\newline
}
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-return
- c_func(10,9);
+return c_func(10,9,8);
\newline
}
\end_layout
\begin_layout Standard
-The corresponding assembler routine is:
+The corresponding (unoptimized) assembler routine is:
\end_layout
\begin_layout Verse
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-push _bp
+push\InsetSpace ~
+_bp
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov _bp,sp
+mov\InsetSpace ~
+\InsetSpace ~
+_bp,sp\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+;stack contains: _bp, return
+ address, second parameter, third parameter
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov r2,dpl
+mov\InsetSpace ~
+\InsetSpace ~
+r2,dpl
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov a,_bp
+mov\InsetSpace ~
+\InsetSpace ~
+a,_bp
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-add
- a,#0xfd
+add\InsetSpace ~
+\InsetSpace ~
+a,#0xfd\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+;calculate
+ pointer to the second parameter
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov r0,a
+mov\InsetSpace ~
+\InsetSpace ~
+r0,a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-add a,#0xfc ;?
+mov\InsetSpace ~
+\InsetSpace ~
+a,_bp
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov r1,a
+add\InsetSpace ~
+\InsetSpace ~
+a,#0xfc\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+;calculate pointer
+ to the rightmost parameter
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov a,@r0
+mov\InsetSpace ~
+\InsetSpace ~
+r1,a
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-add a,r2 ;?
+mov\InsetSpace ~
+\InsetSpace ~
+a,@r0
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov dpl,a
-
+add\InsetSpace ~
+\InsetSpace ~
+a,@r1
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+add\InsetSpace ~
+\InsetSpace ~
+a,r2\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+;calculate the
+ result (= sum of all three parameters)
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+mov\InsetSpace ~
+\InsetSpace ~
+dpl,a\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+;return value goes into dptr
+ (cast into int)
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov dph,#0x00
+mov\InsetSpace ~
+\InsetSpace ~
+dph,#0x00
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-mov sp,_bp
+mov\InsetSpace ~
+\InsetSpace ~
+sp,_bp
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-pop _bp
+pop\InsetSpace ~
+\InsetSpace ~
+_bp
\newline
\InsetSpace ~
\InsetSpace ~
not
\emph default
support long variables and field widths).
- Be sure to only use only one of these printf options within a project.
+ Be sure to use only one of these printf options within a project.
\newline
\end_layout
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
\end_layout
\begin_layout Standard
-SDCC supports the following #pragma directives:
+Pragmas are used to turn on and/or off certain compiler options.
+ Some of them are closely related to corresponding command-line options
+ (see section
+\begin_inset LatexCommand \vref{sec:Command-Line-Options}
+
+\end_inset
+
+).
+\newline
+Pragmas should be placed before and/or after a function, placing pragmas
+ inside a function body could have unpredictable results.
+\newline
+
+\newline
+SDCC supports the
+ following #pragma directives:
\end_layout
\begin_layout Itemize
\end_inset
- function1[,function2[,function3...]] - The compiler by default uses a caller
- saves convention for register saving across function calls, however this
- can cause unnecessary register pushing & popping
+ function1[,function2[,function3...]]
+\begin_inset LatexCommand \label{ite:callee_saves-function1[,function2[,function3...]]--}
+
+\end_inset
+
+- The compiler by default uses a caller saves convention for register saving
+ across function calls, however this can cause unnecessary register pushing
+ and popping
\begin_inset LatexCommand \index{push/pop}
\end_inset
This option can be used to switch off the register saving convention for
the function names specified.
The compiler will not save registers when calling these functions, extra
- code need to be manually inserted at the entry & exit for these functions
- to save & restore the registers used by these functions, this can SUBSTANTIALLY
- reduce code & improve run time performance of the generated code.
+ code need to be manually inserted at the entry and exit for these functions
+ to save and restore the registers used by these functions, this can SUBSTANTIAL
+LY reduce code and improve run time performance of the generated code.
In the future the compiler (with inter procedural analysis) may be able
to determine the appropriate scheme to use for each function call.
If -
\end_inset
--callee-saves command line option is used, the function names specified
- in #pragma\InsetSpace ~
+-callee-saves command line option is used (see page
+\begin_inset LatexCommand \vpageref{lyx:--callee-saves-function1[,function2][,function3]...}
+
+\end_inset
+
+), the function names specified in #pragma\InsetSpace ~
callee_saves
\begin_inset LatexCommand \index{\#pragma callee\_saves}
less_pedantic
\series default
+\begin_inset LatexCommand \index{pedantic}
+
+\end_inset
+
+
\begin_inset LatexCommand \index{\#pragma less\_pedantic}
\end_inset
- - the compiler will not warn you anymore for obvious mistakes, you'r on
- your own now ;-(
+
+\begin_inset LatexCommand \label{ite:less_pedantic}
+
+\end_inset
+
+- the compiler will not warn you anymore for obvious mistakes, you're on
+ your own now ;-( .
+ See also the command line option -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-less-pedantic
+\begin_inset LatexCommand \vpageref{lyx:--less-pedantic}
+
+\end_inset
+
+.
+
+\newline
+More specifically, the following warnings will be disabled:
+\shape italic
+comparison is always [true/false] due to limited range of data type
+\shape default
+ (94);
+\shape italic
+overflow in implicit constant conversion
+\shape default
+ (158); [the (in)famous]
+\shape italic
+conditional flow changed by optimizer: so said EVELYN the modified DOG
+\shape default
+ (110);
+\shape italic
+function '[function name]' must return value
+\shape default
+ (59).
+
+\newline
+Furthermore, warnings of less importance (of PEDANTIC and INFO warning
+ level) are disabled, too, namely:
+\shape italic
+constant value '[
+\begin_inset Note Note
+status collapsed
+
+\begin_layout Standard
+dunno what comes here - this warning appears to be unused altogether
+\end_layout
+
+\end_inset
+
+]', out of range
+\shape default
+ (81);
+\shape italic
+[left/right] shifting more than size of object changed to zero
+\shape default
+ (116);
+\shape italic
+unreachable code
+\shape default
+ (126);
+\shape italic
+integer overflow in expression
+\shape default
+ (165);
+\shape italic
+unmatched #pragma save and #pragma restore
+\shape default
+ (170);
+\shape italic
+comparison of 'signed char' with 'unsigned char' requires promotion to int
+\shape default
+ (185);
+\shape italic
+ISO C90 does not support flexible array members
+\shape default
+ (187);
+\shape italic
+extended stack by [number] bytes for compiler temp(s) :in function '[function\InsetSpace ~
+nam
+e]':\InsetSpace ~
+[
+\begin_inset Note Note
+status collapsed
+
+\begin_layout Standard
+appears to be always blank - what was supposed to be here?
+\end_layout
+
+\end_inset
+
+]
+\shape default
+ (114);
+\shape italic
+function '[function name]', # edges [number] , # nodes [number] , cyclomatic
+ complexity [number]
+\shape default
+ (121).
\end_layout
\begin_layout Itemize
pedantic_parse_number
\series default
+\begin_inset LatexCommand \index{pedantic}
+
+\end_inset
+
+
\begin_inset LatexCommand \index{\#pragma pedantic\_parse\_number}
\end_inset
- (+ | -) - Pedantic parse numbers so that situations like 0xfe-LO_B(3) are
- parsed properly and the macro LO_B(3) gets expanded.
+ (+ | -)
+\begin_inset LatexCommand \label{ite:pedantic_parse_number}
+
+\end_inset
+
+- Pedantic parse numbers so that situations like 0xfe-LO_B(3) are parsed
+ properly and the macro LO_B(3) gets expanded.
Default is off.
- Below is an example on how to use this pragma.
+ See also the -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-pedantic-parse-number command line option
+\begin_inset LatexCommand \vpageref{lyx:-pedantic-parse-number}
+
+\end_inset
+
+.
+
+\newline
+Below is an example on how to use this pragma.
\emph on
Note: this functionality is not in conformance with standard!
\end_layout
\begin_layout Standard
-The pragma's are intended to be used to turn-on or off certain optimizations
- which might cause the compiler to generate extra stack / data space to
- store compiler generated temporary variables.
+Some of the pragmas are intended to be used to turn-on or off certain optimizati
+ons which might cause the compiler to generate extra stack and/or data space
+ to store compiler generated temporary variables.
This usually happens in large functions.
Pragma directives should be used as shown in the following example, they
- are used to control options & optimizations for a given function; pragmas
- should be placed before and/or after a function, placing pragma's inside
- a function body could have unpredictable results.
+ are used to control options and optimizations for a given function.
+
\end_layout
\begin_layout Verse
\begin_layout Standard
The compiler will generate a warning message when extra space is allocated.
- It is strongly recommended that the save and restore pragma's be used when
+ It is strongly recommended that the save and restore pragmas be used when
changing options for a function.
\newline
\begin_layout Standard
\begin_inset Tabular
-<lyxtabular version="3" rows="11" columns="2">
+<lyxtabular version="3" rows="15" columns="2">
<features>
<column alignment="left" valignment="top" leftline="true" width="3in">
<column alignment="left" valignment="top" leftline="true" rightline="true" width="3in">
\end_inset
</cell>
</row>
-<row topline="true" bottomline="true">
+<row topline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
is used
\end_layout
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SDCC_REVISION
+\begin_inset LatexCommand \index{SDCC\_REVISION}
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Always defined.
+ SDCC svn revision number
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SDCC_PARMS_IN_BANK1
+\begin_inset LatexCommand \index{SDCC\_PARMS\_IN\_BANK1}
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+when
+\emph on
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-parms-in-bank1
+\emph default
+ is used
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SDCC_FLOAT_REENT
+\begin_inset LatexCommand \index{SDCC\_MODEL\_FLAT24}
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+when
+\emph on
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-float-reent
+\emph default
+ is used
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SDCC_INT_LONG_REENT
+\begin_inset LatexCommand \index{SDCC\_INT\_LONG\_REENT}
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+when
+\emph on
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-int-long-reent
+\emph default
+ is used
+\end_layout
+
\end_inset
</cell>
</row>
\end_inset
-\begin_inset LatexCommand \index{MCS51 variants}
-
-\end_inset
-
+\begin_inset LatexCommand \index{MCS51 variants}
+
+\end_inset
+
+
+\end_layout
+
+\begin_layout Standard
+MCS51 processors are available from many vendors and come in many different
+ flavours.
+ While they might differ considerably in respect to Special Function Registers
+ the core MCS51 is usually not modified or is kept compatible.
+
+\end_layout
+
+\begin_layout Subsection
+pdata access by SFR
+\end_layout
+
+\begin_layout Standard
+With the upcome of devices with internal xdata and flash memory devices
+ using port P2
+\begin_inset LatexCommand \index{P2 (mcs51 sfr)}
+
+\end_inset
+
+ as dedicated I/O port is becoming more popular.
+ Switching the high byte for pdata
+\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
+
+\end_inset
+
+ access which was formerly done by port P2 is then achieved by a Special
+ Function Register
+\begin_inset LatexCommand \index{sfr}
+
+\end_inset
+
+.
+ In well-established MCS51 tradition the address of this
+\emph on
+sfr
+\emph default
+ is where the chip designers decided to put it.
+ Needless to say that they didn't agree on a common name either.
+ So that the startup code can correctly initialize xdata variables, you
+ should define an sfr with the name _XPAGE
+\family typewriter
+
+\begin_inset LatexCommand \index{\_XPAGE (mcs51)}
+
+\end_inset
+
+
+\family default
+ at the appropriate location if the default, port P2, is not used for this.
+ Some examples are:
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+__sfr __at (0x85) _XPAGE; /* Ramtron VRS51 family a.k.a.
+ MPAGE */
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+__sfr __at (0x92) _XPAGE; /* Cypress EZ-USB family, Texas Instruments (Chipcon)
+ a.k.a.
+ MPAGE */
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+__sfr __at (0x91) _XPAGE; /* Infineon (Siemens) C500 family a.k.a.
+ XPAGE */
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+__sfr __at (0xaf) _XPAGE; /* some Silicon Labs (Cygnal) chips a.k.a.
+ EMI0CN */
+\end_layout
+
+\begin_layout Verse
+
+\family typewriter
+__sfr __at (0xaa) _XPAGE; /* some Silicon Labs (Cygnal) chips a.k.a.
+ EMI0CN */
+\end_layout
+
+\begin_layout Standard
+For more exotic implementations further customizations may be needed.
+ See section
+\begin_inset LatexCommand \ref{sub:Startup-Code}
+
+\end_inset
+
+ for other possibilities.
+\end_layout
+
+\begin_layout Subsection
+Other Features available by SFR
+\end_layout
+
+\begin_layout Standard
+Some MCS51 variants offer features like Double DPTR
+\begin_inset LatexCommand \index{DPTR}
+
+\end_inset
+
+, multiple DPTR, decrementing DPTR, 16x16 Multiply.
+ These are currently not used for the MCS51 port.
+ If you absolutely need them you can fall back to inline assembly or submit
+ a patch to SDCC.
+\end_layout
+
+\begin_layout Subsection
+Bankswitching
+\end_layout
+
+\begin_layout Standard
+Bankswitching
+\begin_inset LatexCommand \index{Bankswitching}
+
+\end_inset
+
+ (a.k.a.
+ code banking
+\begin_inset LatexCommand \index{code banking}
+
+\end_inset
+
+) is a technique to increase the code space above the 64k limit of the 8051.
+\end_layout
+
+\begin_layout Subsubsection
+Hardware
+\end_layout
+
+\begin_layout Standard
+\begin_inset Tabular
+<lyxtabular version="3" rows="3" columns="4">
+<features>
+<column alignment="center" valignment="top" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" width="0">
+<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
+<row topline="true" bottomline="true">
+<cell multicolumn="1" alignment="center" valignment="top" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+8000-FFFF
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+bank1
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+bank2
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+bank3
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row topline="true" bottomline="true">
+<cell multicolumn="1" alignment="center" valignment="top" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+0000-7FFF
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+common
+\end_layout
+
+\end_inset
+</cell>
+<cell multicolumn="1" alignment="center" valignment="top" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+<cell multicolumn="2" alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row>
+<cell multicolumn="1" alignment="center" valignment="top" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+SiLabs C8051F120 example
+\end_layout
+
+\end_inset
+</cell>
+<cell multicolumn="2" alignment="center" valignment="top" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+<cell multicolumn="2" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+<cell multicolumn="2" alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+
+\end_layout
+
+\end_inset
+</cell>
+</row>
+</lyxtabular>
+
+\end_inset
+
+
+\newline
-\end_layout
+\newline
+Usually the hardware uses some sfr (an output port or an internal sfr) to
+ select a bank and put it in the banked area of the memory map.
+ The selected bank usually becomes active immediately upon assignment to
+ this sfr and when running inside a bank it will switch out this code it
+ is currently running.
+ Therefor you cannot jump or call directly from one bank to another and
+ need to use a so-called trampoline in the common area.
+ For SDCC an example trampoline is in crtbank.asm and you may need to change
+ it to your 8051 derivative or schematic.
+ The presented code is written for the C8051F120.
+\newline
-\begin_layout Standard
-MCS51 processors are available from many vendors and come in many different
- flavours.
- While they might differ considerably in respect to Special Function Registers
- the core MCS51 is usually not modified or is kept compatible.
-
+\newline
+When calling a banked function
+ SDCC will put the LSB of the functions address in register R0, the MSB
+ in R1 and the bank in R2 and then call this trampoline
+\emph on
+__sdcc_banked_call
+\emph default
+.
+ The current selected bank is saved on the stack, the new bank is selected
+ and an indirect jump is made.
+ When the banked function returns it jumps to
+\emph on
+__sdcc_banked_ret
+\emph default
+ which restores the previous bank and returns to the caller.
\end_layout
-\begin_layout Subsection
-pdata access by SFR
+\begin_layout Subsubsection
+Software
\end_layout
\begin_layout Standard
-With the upcome of devices with internal xdata and flash memory devices
- using port P2
-\begin_inset LatexCommand \index{P2 (mcs51 sfr)}
-
-\end_inset
-
- as dedicated I/O port is becoming more popular.
- Switching the high byte for pdata
-\begin_inset LatexCommand \index{pdata (mcs51, ds390 storage class)}
+When writing banked software using SDCC you need to use some special keywords
+ and options.
+ You also need to take over a bit of work from the linker.
+\newline
-\end_inset
+\newline
+To create a function
+ that can be called from another bank it requires the keyword
+\emph on
+banked
+\emph default
- access which was formerly done by port P2 is then achieved by a Special
- Function Register
-\begin_inset LatexCommand \index{sfr}
+\begin_inset LatexCommand \index{banked}
\end_inset
.
- In well-established MCS51 tradition the address of this
+ The caller must see this in the prototype of the callee and the callee
+ needs it for a proper return.
+ Called functions within the same bank as the caller do not need the
\emph on
-sfr
+banked
\emph default
- is where the chip designers decided to put it.
- Needless to say that they didn't agree on a common name either.
- So that the startup code can correctly initialize xdata variables, you
- should define an sfr with the name _XPAGE
-\family typewriter
+ keyword nor do functions in the common area.
+ Beware: SDCC does not know or check if functions are in the same bank.
+ This is your responsibility!
+\newline
-\begin_inset LatexCommand \index{\_XPAGE (mcs51)}
+\newline
+Normally all functions you write end up in
+ the segment CSEG.
+ If you want a function explicitly to reside in the common area put it in
+ segment HOME.
+ This applies for instance to interrupt service routines as they should
+ not be banked.
+\end_layout
-\end_inset
+\begin_layout Standard
+Functions that need to be in a switched bank must be put in a named segment.
+ The name can be mostly anything upto eight characters (e.g.
+ BANK1).
+ To do this you either use -
+\begin_inset ERT
+status collapsed
+\begin_layout Standard
-\family default
- at the appropriate location if the default, port P2, is not used for this.
- Some examples are:
+
+\backslash
+/
\end_layout
-\begin_layout Verse
+\end_inset
-\family typewriter
-__sfr __at (0x92) _XPAGE; /* Cypress EZ-USB family */
-\end_layout
+-codeseg BANK1 (See
+\begin_inset LatexCommand \ref{lyx:-codeseg}
-\begin_layout Verse
+\end_inset
-\family typewriter
-__sfr __at (0xaf) _XPAGE; /* some Silicon Labs (Cygnal) chips */
-\end_layout
+) on the command line when compiling or #pragma codeseg BANK1 (See
+\begin_inset LatexCommand \ref{sec:Pragmas}
-\begin_layout Verse
+\end_inset
-\family typewriter
-__sfr __at (0xaa) _XPAGE; /* some Silicon Labs (Cygnal) chips */
-\end_layout
+) at the top of the C source file.
+ The segment name always applies to the whole source file and generated
+ object so functions for different banks need to be defined in different
+ source files.
+\newline
-\begin_layout Standard
-For more exotic implementations further customizations may be needed.
- See section
-\begin_inset LatexCommand \ref{sub:Startup-Code}
+\newline
+When linking your objects you need to tell the linker where
+ to put your segments.
+ To do this you use the following command line option to SDCC: -Wl-b BANK1=0x180
+00 (See
+\begin_inset LatexCommand \ref{lyx:-Wl option}
\end_inset
- for other possibilities.
-\end_layout
-
-\begin_layout Subsection
-Other Features available by SFR
+).
+ This sets the virtual start address of this segment.
+ It sets the banknumber to 0x01 and maps the bank to 0x8000 and up.
+ The linker will not check for overflows, again this is your responsibility.
\end_layout
\begin_layout Standard
-Some MCS51 variants offer features like Double DPTR
-\begin_inset LatexCommand \index{DPTR}
-
-\end_inset
-
-, multiple DPTR, decrementing DPTR, 16x16 Multiply.
- These are currently not used for the MCS51 port.
- If you absolutely need them you can fall back to inline assembly or submit
- a patch to SDCC.
\begin_inset VSpace bigskip
\end_inset
\end_layout
-\begin_layout Standard
-
-\newpage
+\begin_layout Section
+The PIC14
+\begin_inset LatexCommand \index{PIC14}
-\end_layout
+\end_inset
-\begin_layout Section
-The PIC14 port
+ port
\end_layout
\begin_layout Standard
-The 14bit PIC
+The PIC14 port adds support for Microchip
+\begin_inset LatexCommand \index{Microchip}
+
+\end_inset
+
+
+\begin_inset Formula $^{\text{TM}}$
+\end_inset
+
+ PIC
\begin_inset LatexCommand \index{PIC14}
\end_inset
- port still requires a major effort from the development community.
- However it can work for simple code.
- It passes its (smaller set of) regression tests
-\begin_inset LatexCommand \index{Regression test (PIC14)}
+\begin_inset Formula $^{\text{TM}}$
\end_inset
- in the directory
-\shape italic
-sdcc/src/regression
-\shape default
-.
+ MCUs with 14 bit wide instructions.
+ This port is not yet mature and still lacks many features.
+ However, it can work for simple code.
+\end_layout
+
+\begin_layout Standard
+Currently supported devices include:
+\end_layout
+
+\begin_layout Standard
+12F: 629, 635, 675, 683
+\end_layout
+
+\begin_layout Standard
+16C: 432, 433
+\end_layout
+
+\begin_layout Standard
+16C: 554, 557, 558
+\end_layout
+
+\begin_layout Standard
+16C: 62, 620, 620a, 621, 621a, 622, 622a, 63a, 65b
+\end_layout
+
+\begin_layout Standard
+16C: 71, 710, 711, 715, 717, 72, 73b, 745, 74b, 765, 770, 771, 773, 774,
+ 781, 782
+\end_layout
+
+\begin_layout Standard
+16C: 925, 926
+\end_layout
+
+\begin_layout Standard
+16CR: 620a, 73, 74, 76, 77
+\end_layout
+
+\begin_layout Standard
+16F: 616, 627, 627a, 628, 628a, 630, 636, 639, 648, 648a, 676, 684, 685,
+ 687, 688, 689, 690
+\end_layout
+
+\begin_layout Standard
+16F: 716, 72, 73, 737, 74, 747, 76, 767, 77, 777, 785
+\end_layout
+
+\begin_layout Standard
+16F: 818, 819, 84, 84a, 87, 870, 871, 872, 873, 873a, 874, 874a, 876, 876a,
+ 877, 877a, 88, 886, 887
+\end_layout
+
+\begin_layout Standard
+16F: 913, 914, 916, 917, 946
+\end_layout
+
+\begin_layout Standard
+26HV: 626, 785
+\end_layout
+
+\begin_layout Standard
+An up-to-date list of currently supported devices can be obtained via
+\family typewriter
+sdcc -mpic14 -phelp foo.c
+\family default
+ (foo.c must exist...).
\end_layout
\begin_layout Subsection
-C code and 14bit PIC code page
+PIC Code Pages
\begin_inset LatexCommand \index{code page (pic14)}
\end_inset
- and RAM banks
-\begin_inset LatexCommand \index{RAM bank (pic14)}
+ and Memory Banks
+\begin_inset LatexCommand \index{Memory bank (pic14)}
\end_inset
\begin_layout Standard
The linker organizes allocation for the code page and RAM banks.
It does not have intimate knowledge of the code flow.
- It will put all the code section of a single asm file into a single code
+ It will put all the code section of a single .asm file into a single code
page.
In order to make use of multiple code pages, separate asm files must be
used.
- The compiler treats all functions of a single C file as being in the same
- code page unless it is non static.
+ The compiler assigns all
+\emph on
+static
+\emph default
+ functions of a single .c file into the same code page.
\newline
\newline
-To get the best follow these guide lines:
+To get the best results,
+ follow these guidelines:
\end_layout
\begin_layout Enumerate
Make local functions static, as non static functions require code page selection
overhead.
+\newline
+Due to the way sdcc handles functions, place called functions prior
+ to calling functions in the file wherever possible: Otherwise sdcc will
+ insert unneccessary pagesel directives around the call, believing that
+ the called function is externally defined.
\end_layout
\begin_layout Enumerate
For devices that have multiple code pages it is more efficient to use the
- same number of files as pages, i.e.
- for the 16F877 use 4 separate files and i.e.
- for the 16F874 use 2 separate files.
+ same number of files as pages: Use up to 4 separate .c files for the 16F877,
+ but only 2 files for the 16F874.
This way the linker can put the code for each file into different code
- pages and there's less page selection overhead.
+ pages and there will be less page selection overhead.
\end_layout
\begin_layout Enumerate
- And as for any 8 bit micro (especially for PIC 14 as they have a very simple
- instruction set), use 'unsigned char' whereever possible instead of 'int'.
+And as for any 8 bit micro (especially for PIC14 as they have a very simple
+ instruction set), use `unsigned char' wherever possible instead of `int'.
\end_layout
\begin_layout Subsection
-Creating a device include file
+Adding New Devices to the Port
\end_layout
\begin_layout Standard
-For generating a device include file
-\begin_inset LatexCommand \index{PIC14!Header files}
+Adding support for a new 14
+\begin_inset ERT
+status open
+
+\begin_layout Standard
+
+
+\backslash
+,
+\end_layout
\end_inset
- use the support perl script inc2h.pl kept in directory support/script.
+bit PIC MCU requires the following steps:
+\end_layout
+
+\begin_layout Enumerate
+Create a new device description.
+\newline
+Each device is described in two files: pic16f*.h
+ and pic16f*.c.
+ These files primarily define SFRs, structs to access their bits, and symbolic
+ configuration options.
+ Both files can be generated from gputils' .inc files using the perl script
+
+\family typewriter
+support/scripts/inc2h.pl
+\family default
+.
+ This file also contains further instructions on how to proceed.
+\end_layout
+
+\begin_layout Enumerate
+Copy the .h file into SDCC's include path and either add the .c file to your
+ project or copy it to
+\family typewriter
+device/lib/pic/libdev
+\family default
+.
+ Afterwards, rebuild and install the libraries.
+\end_layout
+
+\begin_layout Enumerate
+Edit pic14devices.txt in SDCC's include path (
+\family typewriter
+device/include/pic/
+\family default
+ in the source tree or
+\family typewriter
+/usr/local/share/sdcc/include/pic
+\family default
+ after installation).
+\newline
+You need to add a device specification here to make
+ the memory layout (code banks, RAM, aliased memory regions, ...) known to
+ the compiler.
+ Probably you can copy and modify an existing entry.
+ The file format is documented at the top of the file.
\end_layout
\begin_layout Subsection
-Interrupt code
+Interrupt Code
\end_layout
\begin_layout Standard
-For the interrupt function, use the keyword '__interrupt'
+For the interrupt function, use the keyword `__interrupt'
\begin_inset LatexCommand \index{PIC14!interrupt}
\end_inset
\end_layout
\begin_layout Subsection
-Linking and assembling
+Linking and Assembling
\end_layout
\begin_layout Standard
\end_inset
gpasm.exe or MPLAB's mpasmwin.exe.
- GPUTILS is available from
+ GPUTILS are available from
\begin_inset LatexCommand \url{http://sourceforge.net/projects/gputils}
\end_inset
.
- For linking you can use either GPUTIL's gplink or MPLAB's mplink.exe.
+ For linking you can use either GPUTILS' gplink or MPLAB's mplink.exe.
If you use MPLAB and an interrupt function then the linker script file
vectors section will need to be enlarged to link with mplink.
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-sdcc -S -V -mpic14 -p16F877 $<
-\newline
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-\InsetSpace ~
-gpasm -c $*.asm
+sdcc -V -mpic14 -p16f877 -c $<
\newline
\newline
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-gplink
- -m -s $(PRJ).lkr -o $(PRJ).hex $(OBJS) libsdcc.lib
+gplink -m -s $(PRJ).lkr
+ -o $(PRJ).hex $(OBJS) libsdcc.lib
\end_layout
\begin_layout Standard
\InsetSpace ~
\InsetSpace ~
\InsetSpace ~
-sdcc -S -V -mpic14 -p16F877 $<
+sdcc -S -V -mpic14 -p16f877 $<
\newline
\InsetSpace ~
\InsetSpace ~
\end_layout
\begin_layout Subsection
-Command-line options
+Command-Line Options
\end_layout
\begin_layout Standard
-help):
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--debug-extra
+-debug-xtra
\begin_inset LatexCommand \index{PIC14!Options!-\/-debug-extra}
\end_inset
emit debug info in assembly output
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
disable (slightly faulty) optimization on pCode
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
large shared databank to reduce BANKSEL overhead)
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_layout
\begin_layout Subsection
-The library
+Environment Variables
\end_layout
-\begin_layout Subsubsection
-error: missing definition for symbol
-\begin_inset Quotes sld
-\end_inset
+\begin_layout Standard
+The PIC14 port recognizes the following environment variables:
+\end_layout
-__gptrget1
-\begin_inset Quotes srd
-\end_inset
+\begin_layout Description
+SDCC_PIC14_SPLIT_LOCALS If set and not empty, sdcc will allocate each temporary
+ register (the ones called r0xNNNN) in a section of its own.
+ By default (if this variable is unset), sdcc tries to cluster registers
+ in sections in order to reduce the BANKSEL overhead when accessing them.
+\end_layout
+
+\begin_layout Subsection
+The Library
+\end_layout
+\begin_layout Standard
+The PIC14 library currently only contains support routines required by the
+ compiler to implement multiplication, division, and floating point support.
+ No libc-like replacement is available at the moment, though many of the
+ common sdcc library sources (in
+\family typewriter
+device/lib
+\family default
+) should also compile with the PIC14 port.
+\end_layout
+\begin_layout Subsubsection
+error: missing definition for symbol ``__gptrget1''
\end_layout
\begin_layout Standard
\end_layout
\begin_layout Subsubsection
-Processor mismatch in file
-\begin_inset Quotes sld
-\end_inset
-
-XXX
-\begin_inset Quotes srd
-\end_inset
-
-.
+Processor mismatch in file ``XXX''.
\end_layout
\begin_layout Standard
This warning can usually be ignored due to the very good compatibility amongst
- 14 bit PIC
+ 14
+\begin_inset ERT
+status open
+
+\begin_layout Standard
+
+
+\backslash
+,
+\end_layout
+
+\end_inset
+
+bit PIC
\begin_inset LatexCommand \index{PIC14}
\end_inset
\family default
to reflect your device.
This might even improve performance for smaller devices as unneccesary
- BANKSELs migth be removed.
+ BANKSELs might be removed.
\end_layout
\begin_layout Subsection
-Known bugs
+Known Bugs
\end_layout
\begin_layout Subsubsection
-initialized data
+Function arguments
\end_layout
\begin_layout Standard
-Currently, data can only be initialized if it resides in the source file
- together with
-\emph on
-main()
-\emph default
-.
- Data in other source files will silently
-\series bold
-not
-\series default
- be initialized.
-\family typewriter
-\size footnotesize
-
-\begin_inset Marginal
-status collapsed
-
-\begin_layout Standard
-
-\series bold
-\InsetSpace ~
-!
+Functions with variable argument lists (like printf) are not yet supported.
+ Similarly, taking the address of the first argument passed into a function
+ does not work: It is currently passed in WREG and has no address...
\end_layout
-\end_inset
-
+\begin_layout Subsubsection
+Regression tests fail
+\end_layout
+\begin_layout Standard
+Though the small subset of regression tests in src/regression passes, SDCC
+ regression test suite does not, indicating that there are still major bugs
+ in the port.
+ However, many smaller projects have successfully used SDCC in the past...
\end_layout
\begin_layout Standard
+\size footnotesize
+
\newpage
\end_layout
\end_layout
\begin_layout Standard
-The PIC16
-\begin_inset LatexCommand \index{PIC16}
-
-\end_inset
-
- port is the portion of SDCC that is responsible to produce code for the
- Microchip
+The PIC16 port adds support for Microchip
\begin_inset LatexCommand \index{Microchip}
\end_inset
-(TM) microcontrollers with 16 bit core.
- Currently this family of microcontrollers contains the PIC18Fxxx and PIC18Fxxxx.
- Currently supported devices are:
-\end_layout
-
-\begin_layout Standard
-\align center
-\begin_inset Tabular
-<lyxtabular version="3" rows="4" columns="6">
-<features>
-<column alignment="center" valignment="top" leftline="true" width="0">
-<column alignment="center" valignment="top" leftline="true" width="0">
-<column alignment="center" valignment="top" leftline="true" width="0">
-<column alignment="center" valignment="top" leftline="true" width="0">
-<column alignment="center" valignment="top" leftline="true" width="0">
-<column alignment="center" valignment="top" leftline="true" rightline="true" width="0">
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F242
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F248
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F252
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F258
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F442
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F448
-\end_layout
-
-\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F452
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F458
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F1220
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F2220
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F2550
-\end_layout
-
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
-\begin_layout Standard
-18F4331
-\end_layout
+\begin_inset Formula $^{\text{TM}}$
\end_inset
-</cell>
-</row>
-<row topline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-18F4455
-\end_layout
+ PIC
+\begin_inset LatexCommand \index{PIC}
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-18F6520
-\end_layout
+\begin_inset Formula $^{\text{TM}}$
\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-\begin_layout Standard
-18F6620
+ MCUs with 16 bit wide instructions.
+ Currently this family of microcontrollers contains the PIC18Fxxx and PIC18Fxxxx
+; devices supported by the port include:
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-18F6680
+18F: 242, 248, 252, 258, 442, 448, 452, 458
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-18F6720
+18F: 1220, 1320
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-18F8520
+18F: 2220, 2221, 2320, 2321, 2331, 2420, 2423, 2431, 2455, 2480, 24j10
\end_layout
-\end_inset
-</cell>
-</row>
-<row topline="true" bottomline="true">
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-18F8620
+18F: 2520, 2523, 2525, 2550, 2580, 2585, 25j10, 2620, 2680, 2682, 2685
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-18F8680
+18F: 4220, 4221, 4320, 4321, 4331, 4420, 4423, 4431, 4455, 4480, 44j10
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-18F8720
+18F: 4520, 4523, 4525, 4550, 4580, 4585, 45j10, 4620, 4680, 4682, 4685
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-
+18F: 6520, 6585, 6620, 6680, 6720
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-
+18F: 8520, 8585, 8620, 8680, 8720
\end_layout
-\end_inset
-</cell>
-<cell alignment="center" valignment="top" topline="true" leftline="true" rightline="true" usebox="none">
-\begin_inset Text
-
\begin_layout Standard
-
-\end_layout
-
-\end_inset
-</cell>
-</row>
-</lyxtabular>
-
-\end_inset
-
-
+A list of supported devices is also available via '
+\family typewriter
+sdcc -mpic16 -plist
+\family default
+'.
\end_layout
\begin_layout Subsection
list:
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
-all-callee-saves
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--all-callee-saves
-\begin_inset LatexCommand \index{PIC16!Options!-\/-all-callee-saves}
-
-\end_inset
-
- All function arguments are passed on stack by default.
-
-\emph on
-There is no need to specify this in the command line.
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_layout
\begin_layout Standard
-The port specific options appear after the global options in the sdcc --help
- output.
+The port specific options appear after the global options in the sdcc -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-help output.
\end_layout
\begin_layout Subsubsection
-General Options
+Code Generation Options
\end_layout
\begin_layout Standard
-General options enable certain port features and optimizations.
+These options influence the generated assembler code.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
-pstack-model=[model] Used in conjuction with the command above.
- Defines the stack model to be used, valid stack models are :
+ Defines the stack model to be used, valid stack models are:
\end_layout
\begin_deeper
\end_layout
\end_deeper
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--preplace-udata-with=[kword] Replaces the default udata keyword for allocating
- unitialized data variables with [kword].
- Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
+-pno-banksel Do not generate BANKSEL assembler directives.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--ivt-loc <nnnn> positions the Interrupt Vector Table at location <nnnn>.
- Useful for bootloaders.
+-extended Enable extended instruction set/literal offset addressing mode.
+ Use with care!
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Subsubsection
+Optimization Options
+\end_layout
+
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--asm= sets the full path and name of an external assembler to call.
+-obanksel=n Set optimization level for inserting BANKSELs.
+\newline
+
\end_layout
+\begin_deeper
\begin_layout List
\labelwidthstring 00.00.0000
+0 no optimization
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+1 checks previous used register and if it is the same then does not emit
+ BANKSEL, accounts only for labels.
+\end_layout
+
+\begin_layout List
+\labelwidthstring 00.00.0000
+2 tries to check the location of (even different) symbols and removes BANKSELs
+ if they are in the same bank.
+
+\newline
+
+\emph on
+Important: There might be problems if the linker script has data sections
+ across bank borders!
+\end_layout
+
+\end_deeper
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--link= sets the full path and name of an external linker to call.
+-denable-peeps Force the usage of peepholes.
+ Use with care.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--mplab-comp MPLAB
-\begin_inset LatexCommand \index{PIC16!MPLAB}
+-no-optimize-goto Do not use (conditional) BRA instead of GOTO.
+\end_layout
-\end_inset
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
- compatibility option.
- Currently only suppresses special gpasm directives.
+\begin_layout Standard
+
+
+\backslash
+/
\end_layout
-\begin_layout Subsubsection
-Optimization Options
+\end_inset
+
+-optimize-cmp Try to optimize some compares.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--optimize-goto Try to use (conditional) BRA instead of GOTO
+-optimize-df Analyze the dataflow of the generated code and improve it.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Subsubsection
+Assembling Options
+\end_layout
+
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--optimize-cmp Try to optimize some compares.
+-asm= Sets the full path and name of an external assembler to call.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--optimize-df Analyze the dataflow of the generated code and improve it.
+-mplab-comp MPLAB
+\begin_inset LatexCommand \index{PIC16!MPLAB}
+
+\end_inset
+
+ compatibility option.
+ Currently only suppresses special gpasm directives.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Subsubsection
+Linking Options
+\end_layout
+
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--obanksel=nn Set optimization level for inserting BANKSELs.
-\newline
-
+-link= Sets the full path and name of an external linker to call.
\end_layout
-\begin_deeper
-\begin_layout List
-\labelwidthstring 00.00.0000
-0 no optimization
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
-1 checks previous used register and if it is the same then does not emit
- BANKSEL, accounts only for labels.
+\end_inset
+
+-preplace-udata-with=[kword] Replaces the default udata keyword for allocating
+ unitialized data variables with [kword].
+ Valid keywords are: "udata_acs", "udata_shr", "udata_ovr".
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
-2 tries to check the location of (even different) symbols and removes BANKSELs
- if they are in the same bank.
-
-\newline
+\begin_layout Description
+-
+\begin_inset ERT
+status collapsed
-\emph on
-Important: There might be problems if the linker script has data sections
- across bank borders!
+\begin_layout Standard
+
+
+\backslash
+/
\end_layout
-\end_deeper
-\begin_layout Subsubsection
-Linking Options
+\end_inset
+
+-ivt-loc=n Place the interrupt vector table at address
+\emph on
+n
+\emph default
+.
+ Useful for bootloaders.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--nodefaultlibs do not link default libraries when linking
+-nodefaultlibs Do not link default libraries when linking.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--no-crt Don't link the default run-time modules
+-use-crt= Use a custom run-time module instead of the defaults.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--use-crt= Use a custom run-time module instead of the defaults.
+-no-crt Don't link the default run-time modules
\end_layout
\begin_layout Subsubsection
Debugging options enable extra debugging information in the output files.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
, but dumps more information.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
-debug-ralloc Force register allocator to dump <source>.d file with debugging
information.
- <source> is the name of the file compiled.
+ <source> is the name of the file being compiled.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
-pcode-verbose Enable pcode debugging information in translation.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--denable-peeps Force the usage of peepholes.
- Use with care.
+-calltree Dump call tree in .calltree file.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
-
\begin_inset ERT
status collapsed
\end_inset
--gstack Trace push/pops for stack pointer overflow
-\end_layout
-
-\begin_layout List
-\labelwidthstring 00.00.0000
--
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-
-\backslash
-/
-\end_layout
-
-\end_inset
-
--call-tree dump call tree in .calltree file
+-gstack Trace push/pops for stack pointer overflow.
\end_layout
\begin_layout Subsection
-Enviromental Variables
+Enviroment Variables
\end_layout
\begin_layout Standard
Currently there is only two such variables available:
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
-OPTIMIZE_BITFIELD_POINTER_GET when this variable exists reading of structure
+\begin_layout Description
+OPTIMIZE_BITFIELD_POINTER_GET When this variable exists, reading of structure
bitfields is optimized by directly loading FSR0 with the address of the
bitfield structure.
Normally SDCC will cast the bitfield structure to a bitfield pointer and
then load FSR0.
- This step saves data ram and code space for functions that perform heavy
- use of bitfields.
- (ie.
- 80 bytes of code space are saved when compiling malloc.c with this option).
+ This step saves data ram and code space for functions that make heavy use
+ of bitfields.
+ (i.e., 80 bytes of code space are saved when compiling malloc.c with this
+ option).
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
-NO_REG_OPT do not perform pCode registers optimization.
+\begin_layout Description
+NO_REG_OPT Do not perform pCode registers optimization.
This should be used for debugging purposes.
- In some where bugs in the pcode optimizer are found, users can benefit
- from temporarily disabling the optimizer until the bug is fixed.
+ If bugs in the pcode optimizer are found, users can benefit from temporarily
+ disabling the optimizer until the bug is fixed.
\end_layout
\begin_layout Subsection
\end_layout
\begin_layout Standard
-PIC16
+The PIC16
\begin_inset LatexCommand \index{PIC16}
\end_inset
port currently supports the following pragmas:
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
stack
\begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma stack}
\end_inset
- pragma stack
-\begin_inset LatexCommand \index{PIC16!stack}
-
-\end_inset
-
- forces the code generator to initialize the stack & frame pointers at a
- specific address.
- This is an adhoc solution for cases where no STACK directive is available
+ This forces the code generator to initialize the stack & frame pointers
+ at a specific address.
+ This is an ad hoc solution for cases where no STACK directive is available
in the linker script or gplink is not instructed to create a stack section.
\newline
The
\newline
The format is as follows:
+\newline
+
\end_layout
\begin_layout LyX-Code
#pragma stack bottom_address [stack_size]
+\newline
+
\end_layout
\begin_layout Standard
with deep function nesting or excessive stack usage.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
code
\begin_inset LatexCommand \index{PIC16!Pragmas!\#pragma code}
\end_inset
- place a function symbol at static FLASH address
+ Force a function to a static FLASH address.
\end_layout
\begin_layout LyX-Code
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
library instructs the linker to use a library module.
\newline
Usage:
keyword will reject all modules specified by the library pragma.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
-udata pragma udata instructs the compiler to emit code so that linker will
- place a variable at a specific memory bank
+\begin_layout Description
+udata The pragma udata instructs the compiler to emit code so that linker
+ will place a variable at a specific memory bank.
\end_layout
\begin_layout LyX-Code
\end_layout
\begin_layout Standard
-The steps to compile the pic16 libraries under Linux are:
+The steps to compile the pic16 libraries under Linux and Mac OS X are:
\end_layout
\begin_layout LyX-Code
make lib-io
\end_layout
+\begin_layout Subsection
+Adding New Devices to the Port
+\end_layout
+
+\begin_layout Standard
+Adding support for a new 16
+\begin_inset ERT
+status open
+
+\begin_layout Standard
+
+
+\backslash
+,
+\end_layout
+
+\end_inset
+
+bit PIC MCU requires the following steps:
+\end_layout
+
+\begin_layout Enumerate
+Create picDEVICE.c and picDEVICE.h from pDEVICE.inc using
+\newline
+
+\family typewriter
+perl /path/to/sdcc/support/scripts/inc2h-pic16.pl /path/to/gputils/header/pDEVICE.
+inc
+\end_layout
+
+\begin_layout Enumerate
+
+\family typewriter
+mv picDEVICE.h /path/to/sdcc/device/include/pic16
+\end_layout
+
+\begin_layout Enumerate
+
+\family typewriter
+mv picDEVICE.c /path/to/sdcc/device/lib/pic16/libdev
+\end_layout
+
+\begin_layout Enumerate
+Add DEVICE to
+\family typewriter
+/path/to/sdcc/device/lib/pic16/pics.all
+\family default
+ (and
+\family typewriter
+.build
+\family default
+).
+\newline
+Note: No 18f prefix here!
+\end_layout
+
+\begin_layout Enumerate
+Set up the I/O library by doing
+\series bold
+one
+\series default
+ of the following:
+\end_layout
+
+\begin_deeper
+\begin_layout Enumerate
+Adjust
+\family typewriter
+/path/to/sdcc/device/lib/pic16/libio/*.ignore
+\family default
+
+\newline
+Add your DEVICE if it does not compile in
+\family typewriter
+adc
+\family default
+,
+\family typewriter
+i2c
+\family default
+, or
+\family typewriter
+usart
+\family default
+.
+\end_layout
+
+\begin_layout Enumerate
+Adjust
+\family typewriter
+/path/to/sdcc/device/include/pic16/adc.h
+\newline
+
+\family default
+Add the new devices to the correct ADC style class.
+\end_layout
+
+\end_deeper
+\begin_layout Enumerate
+Edit
+\family typewriter
+/path/to/sdcc/device/include/pic16/pic18fregs.h
+\family default
+.
+ The file format is self-explanatory, just add
+\newline
+
+\family typewriter
+#elif defined(picDEVICE)
+\newline
+# include <picDEVICE.h>
+\family default
+
+\newline
+at the right place (keep it sorted).
+\end_layout
+
+\begin_layout Enumerate
+Edit
+\family typewriter
+/path/to/sdcc/device/include/pic16devices.txt
+\newline
+
+\family default
+Copy and modify an existing entry or create a new one and insert it at the
+ correct place (keep the file sorted).
+\end_layout
+
+\begin_layout Enumerate
+Recompile the pic16 libraries.
+\end_layout
+
\begin_layout Subsection
Memory Models
\end_layout
FSR2.
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
FSR1 is assigned as stack pointer
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
FSR2 is assigned as frame pointer
\end_layout
port makes available two more:
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
wparam
\begin_inset LatexCommand \index{PIC16!wparam}
}
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
shadowregs
\begin_inset LatexCommand \index{PIC16!shadowregs}
Address of the specific interrupt.
This is not a problem for the LOW priority interrupts, but it is a problem
for the RESET and the HIGH priority interrupts because code may be written
- at the next interrupt´s vector address and cause undeterminate program
+ at the next interrupt's vector address and cause undeterminate program
behaviour if that interrupt is raised.
\begin_inset Foot
status open
\end_layout
\begin_layout Enumerate
-when the ISR is small enough not to reach the next interrupt´s vector address.
+when the ISR is small enough not to reach the next interrupt's vector address.
\end_layout
\end_inset
\emph on
n
\emph default
- is possible to be omitted.
+ may be omitted.
This way a function is generated similar to an ISR, but it is not assigned
to any interrupt.
\end_layout
These are
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
_
\begin_inset ERT
status collapsed
_stream_usart_putchar writes a character at the USART stream
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
_
\begin_inset ERT
status collapsed
_stream_mssp_putchar writes a character at the MSSP stream
\end_layout
-\begin_layout List
-\labelwidthstring 00.00.0000
+\begin_layout Description
putchar dummy function.
This writes a character to a user specified manner.
\end_layout
\end_layout
\begin_layout LyX-Code
- printf (¨This is a printf test
+ printf (
+\begin_inset Quotes sld
+\end_inset
+
+This is a printf test
\backslash
-n¨);
+n
+\begin_inset Quotes srd
+\end_inset
+
+);
\end_layout
\begin_layout LyX-Code
\end_layout
\begin_layout Subsection
-Known bugs
+Known Bugs
\end_layout
\begin_layout Standard
\end_inset
-) and thus the nightly regression tests for the PIC16 target are currently
- disabled for all hosts except for
+) and thus the snapshot build regression tests for the PIC16 target are
+ currently disabled for all hosts
\emph on
-Linux on Opteron.
-
-\emph default
- This means you can see the result of the PIC16 regression tests f.e.
- by checking the log files in
-\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/regression_test_results/amd64-unknown-linux2.3/}
-
-\end_inset
-
- (pick the most up to date file there, scroll down, lend a hand).
+.
\end_layout
\begin_layout Chapter
\end_inset
- ) on howto handle syntax extensions like __xdata, __at(), ...
+) on how to handle syntax extensions like __xdata, __at(), ...
\end_layout
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
raphics File
\size footnotesize
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/doc/figures/ddd_example.png}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/doc/figures/ddd_example.png}
\end_inset
;;
\newline
-\end_layout
-
-\begin_layout Standard
+\family default
\newpage
\end_inset
>
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/compiler.h?view=markup}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/compiler.h?view=markup}
\end_inset
to allow using common header files.
(see f.e.
cc2510fx.h
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/cc2510fx.h?view=markup}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/device/include/mcs51/cc2510fx.h?view=markup}
\end_inset
\newline
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/ChangeLog}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/ChangeLog}
\end_inset
\newline
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/as/doc/asxhtm.html}
\end_inset
\newline
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/doc/}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/sdcc/trunk/sdcc/doc/}
\end_inset
:
\newline
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/debugger/README}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/debugger/README}
\end_inset
\newline
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/sim/ucsim/doc/index.html}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/sim/ucsim/doc/index.html}
\end_inset
\emph default
-\begin_inset LatexCommand \url{http://svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/src/pic16/NOTES}
+\begin_inset LatexCommand \url{http://sdcc.svn.sourceforge.net/viewvc/*checkout*/sdcc/trunk/sdcc/src/pic16/NOTES}
\end_inset
\begin_layout Standard
\align left
\begin_inset Tabular
-<lyxtabular version="3" rows="14" columns="3">
+<lyxtabular version="3" rows="16" columns="3">
<features>
<column alignment="left" valignment="top" leftline="true" width="0pt">
<column alignment="block" valignment="top" leftline="true" width="30line%">
-<column alignment="left" valignment="top" leftline="true" rightline="true" width="0pt">
+<column alignment="left" valignment="top" leftline="true" rightline="true" width="40col%">
<row topline="true" bottomline="true">
<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
\begin_inset Text
\end_inset
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+d52
+\begin_inset LatexCommand \index{d52}
+
+\end_inset
+
+
+\begin_inset LatexCommand \index{d52 (disassembler)}
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Disassembler, can count instruction cycles
+\begin_inset LatexCommand \index{instruction cycles (count)}
+
+\end_inset
+
+, use with options -pnd
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+\begin_inset LatexCommand \url{http://www.8052.com/users/disasm/}
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+</cell>
+</row>
+<row bottomline="true">
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+cmake
+\begin_inset LatexCommand \index{cmake}
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+Cross platform build system, generates Makefiles
+\begin_inset LatexCommand \index{Makefile}
+
+\end_inset
+
+ and project workspaces
+\begin_inset LatexCommand \index{project workspace}
+
+\end_inset
+
+
+\end_layout
+
+\end_inset
+</cell>
+<cell alignment="center" valignment="top" topline="true" leftline="true" usebox="none">
+\begin_inset Text
+
+\begin_layout Standard
+\begin_inset LatexCommand \url{http://www.cmake.org}
+
+\end_inset
+
+ \InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+and a dedicated wiki entry:
+\begin_inset LatexCommand \url{http://www.cmake.org/Wiki/CmakeSdcc}
+
+\end_inset
+
+
\end_layout
\end_inset
in the Subversion repository
\size footnotesize
-\begin_inset LatexCommand \htmlurl{http://svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/ChangeLog}
+\begin_inset LatexCommand \htmlurl{http://sdcc.svn.sourceforge.net/viewcvs.cgi/*checkout*/sdcc/trunk/sdcc/ChangeLog}
\end_inset
The output of
\family sans
\series bold
-sdcc --version
+sdcc -
+\family default
+
+\begin_inset ERT
+status open
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+
+\family sans
+-version
\family default
\series default
or the filenames of the snapshot versions of SDCC include date and its
\end_inset
.
- A release wiki
+ The SDCC Wiki
\begin_inset LatexCommand \index{wiki}
\end_inset
-\begin_inset LatexCommand \index{Release wiki}
+\begin_inset LatexCommand \index{SDCC Wiki}
\end_inset
at
-\begin_inset LatexCommand \url{http://sdcc.sf.net/release_wiki/}
+\begin_inset LatexCommand \url{http://sdcc.wiki.sourceforge.net/}
\end_inset
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
\end_layout
\begin_layout Standard
-The compiler is passed through nightly compile and build checks.
+The compiler is passed through snaphot build compile and build checks.
The so called
\shape italic
regression tests
\end_inset
check that SDCC itself compiles flawlessly on several host platforms (i386,
- Opteron, 64 bit Alpha, ppc64, MacOS X on PPC, Solaris on Sparc) and checks
- the quality of the code generated by SDCC by running the code for several
- target platforms through simulators.
+ Opteron, 64 bit Alpha, ppc64, Mac OS X on ppc and i386, Solaris on Sparc)
+ and checks the quality of the code generated by SDCC by running the code
+ for several target platforms through simulators.
The regression test suite comprises more than 100 files which expand to
more than 500 test cases which include more than 4500 tests.
The results of these tests are published daily on SDCC's snapshot page
\end_layout
\begin_layout Standard
-The 14bit pic port uses a different set of regression tests
+The PIC14 port uses a different set of regression tests
\begin_inset LatexCommand \index{Regression test (PIC14)}
\end_inset
\emph on
their
\emph default
- choice (among them Alpha, i386, i386_64, MacOs, Mips, Sparc, Windows and
- eventually
+ choice (among them Alpha, i386, i386_64, Mac OS X, Mips, Sparc, Windows
+ and eventually
\begin_inset LatexCommand \url[OLPC]{http://www.laptop.org}
\end_inset
\begin_layout Standard
then SDCC is probably among the first choices.
Well, probably SDCC might be the only choice.
-\end_layout
-
-\begin_layout Standard
-
\newpage
\end_layout
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
replace { ljmp %1 } by { ajmp %1 }
\end_layout
+\begin_layout Standard
+(NOTE: from version 2.7.3 on, you can use option -
+\emph on
+
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+
+\emph default
+-acall-ajmp
+\begin_inset LatexCommand \index{-\/-acall-ajmp}
+
+\end_inset
+
+, which also takes care of aligning the interrupt vectors properly.)
+\newline
+
+\end_layout
+
\begin_layout Standard
The
\emph on
\family typewriter
foo(i,j) /* this old style of function declarations */
\newline
-int i,j; /* are valid
+int i,j; /* is valid
in ANSI but not valid in SDCC */
\newline
{
\end_deeper
\begin_layout Itemize
-Most enhancements in C99 are not supported, f.e.:
+Most enhancements in C99 are not supported, e.g.:
+\end_layout
+
+\begin_deeper
+\begin_layout Verse
+
+\family typewriter
+for (
+\series bold
+int
+\series default
+ i=0; i<10; i++) /* is invalid in SDCC although allowed in C99 */
+\end_layout
+
+\end_deeper
+\begin_layout Itemize
+But some have been added recently in SDCC 2.7.0.
+ They must be considered alpha quality however.
\end_layout
\begin_deeper
\series default
- int increment (int a) { return a+1; } /* is invalid in SDCC although allowed
- in C99.
- An empty define
-\emph on
-#define inline
-\emph default
- can be used as a work around */
-\newline
-
+ int increment (int a) { return a+1; } /* inlines the increment without
+ function call overhead */
\newline
-for (
+int *
\series bold
-int
+restrict
+\begin_inset LatexCommand \index{inline (not supported)}
+
+\end_inset
+
+
\series default
- i=0; i<10; i++) /* is invalid in SDCC although allowed in C99 */
+ p; /* accepted but ignored */
\end_layout
\end_deeper
\end_inset
- or -
+
+\series default
+or
+\series bold
+ -
\begin_inset ERT
status collapsed
'__data' instead of 'data'.
\end_layout
+\begin_layout Itemize
+Integer promotion of variable arguments is not performed if the argument
+ is explicitly taypecasted unless the
+\series bold
+ -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-std-c89
+\begin_inset LatexCommand \index{-\/-std-c89}
+
+\end_inset
+
+
+\series default
+or
+\series bold
+ -
+\begin_inset ERT
+status collapsed
+
+\begin_layout Standard
+
+
+\backslash
+/
+\end_layout
+
+\end_inset
+
+-std-c99
+\begin_inset LatexCommand \index{-\/-std-c99}
+
+\end_inset
+
+
+\series default
+ command line options are used.
+\end_layout
+
+\begin_deeper
+\begin_layout Verse
+
+\family typewriter
+void vararg_func (char *str, ...) { str; }
+\newline
+
+\newline
+void main (void)
+\newline
+{
+\newline
+\InsetSpace ~
+\InsetSpace ~
+char c = 10;
+\newline
+
+\newline
+\InsetSpace ~
+\InsetSpace ~
+/* argument
+ u is promoted to int before
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+* passing to function */
+\newline
+\InsetSpace ~
+\InsetSpace ~
+vararg_func ("%c", c);
+\newline
+
+\newline
+\InsetSpace ~
+\InsetSpace ~
+/*
+ argument u is not promoted to int,
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+* it is passed as char to function
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+* if
+ --std-cXX is not defined;
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+* is promoted to int before passing
+\newline
+\InsetSpace ~
+\InsetSpace ~
+\InsetSpace ~
+* to function
+ if --std-cXX is defined */
+\newline
+\InsetSpace ~
+\InsetSpace ~
+vararg_func ("%bc", (char)u);
+\newline
+}
+\end_layout
+
+\end_deeper
\begin_layout Section
Cyclomatic Complexity
\begin_inset LatexCommand \index{Cyclomatic complexity}
\end_layout
\begin_layout Standard
-More information is available in a wiki
+More information is available on SDCC Wiki
\begin_inset LatexCommand \index{wiki}
\end_inset
(preliminary link
-\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/release_wiki/index.php?page=SDCC+internals+and+porting}
+\begin_inset LatexCommand \url{http://sdcc.wiki.sourceforge.net/SDCC+internals+and+porting}
\end_inset
\end_layout
\begin_layout Standard
-\begin_inset Note Comment
+\begin_inset Note Note
status collapsed
\begin_layout Standard
\end_layout
\begin_layout Standard
-\begin_inset LatexCommand \url{http://sdcc.sourceforge.net#Who}
+\begin_inset LatexCommand \url{http://sdcc.sourceforge.net/#Who}
\end_inset
\newline
\emph on
-Also thanks to Sourceforge
+Thanks to Sourceforge
\begin_inset LatexCommand \url{http://www.sf.net}
\end_inset
which has hosted the project since 1999 and donates significant download
- bandwidth and probably more than
-\begin_inset ERT
-status collapsed
-
-\begin_layout Standard
-
-$10^{13}$
-\end_layout
-
-\end_inset
+ bandwidth.
+\emph default
-CPU cycles per day.
\newline
-
-\begin_inset Note Note
-status open
-
-\begin_layout Standard
-more than 10^13 is an estimate: on my Athlon 2800+ it takes about (0.5+6.5+20)
- minutes for (configure+make+regression test), and there is (i386, amd64,
- alpha, ppc64, (mingw32), sparc, macosx).
-
-\end_layout
-\end_inset
+\newline
+\emph on
+Also thanks to all SDCC Distributed Compile Farm members for donating CPU
+ cycles and bandwidth for snapshot builds.
+\newline
\end_layout
projects / fw / sdcc / blobdiff