<article>
<title>cc65 Users Guide
-<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
-<date>03.09.2000, 02.10.2001, 2005-8-1
+<author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">,<newline>
+<url url="mailto:gregdk@users.sf.net" name="Greg King">
<abstract>
cc65 is a C compiler for 6502 targets. It supports several 6502 based home
<!-- Begin the document -->
-
<sect>Overview<p>
cc65 was originally a C compiler for the Atari 8-bit machines written by
up the changes made by me. I have made many more changes in the meantime
(and rewritten major parts of the compiler), so I will no longer do that,
since the list would be too large and of no use to anyone. Instead I will
-describe the compiler in respect to the ANSI/ISO C standard. In fact, I'm
-planning a complete rewrite (that is, a complete new compiler) for the
-next release, since there are too many limitations in the current code,
-and removing these limitations would mean a rewrite of many more parts of
-the compiler.
+describe the compiler in respect to the ANSI/ISO C standard.
There are separate documents named <url url="library.html"> and <url
url="funcref.html"> that cover the library that is available for the compiler.
---------------------------------------------------------------------------
Usage: cc65 [options] file
Short options:
- -Cl Make local variables static
- -Dsym[=defn] Define a symbol
- -I dir Set an include directory search path
- -O Optimize code
- -Oi Optimize code, inline more code
- -Or Enable register variables
- -Os Inline some known functions
- -T Include source as comment
- -V Print the compiler version number
- -W Suppress warnings
- -d Debug mode
- -g Add debug info to object file
- -h Help (this text)
- -j Default characters are signed
- -o name Name the output file
- -r Enable register variables
- -t sys Set the target system
- -v Increase verbosity
+ -Cl Make local variables static
+ -Dsym[=defn] Define a symbol
+ -E Stop after the preprocessing stage
+ -I dir Set an include directory search path
+ -O Optimize code
+ -Oi Optimize code, inline more code
+ -Or Enable register variables
+ -Os Inline some standard functions
+ -T Include source as comment
+ -V Print the compiler version number
+ -W warning[,...] Suppress warnings
+ -d Debug mode
+ -g Add debug info to object file
+ -h Help (this text)
+ -j Default characters are signed
+ -mm model Set the memory model
+ -o name Name the output file
+ -r Enable register variables
+ -t sys Set the target system
+ -v Increase verbosity
Long options:
- --add-source Include source as comment
- --bss-name seg Set the name of the BSS segment
- --check-stack Generate stack overflow checks
- --code-name seg Set the name of the CODE segment
- --codesize x Accept larger code by factor x
- --cpu type Set cpu type
- --create-dep Create a make dependency file
- --data-name seg Set the name of the DATA segment
- --debug Debug mode
- --debug-info Add debug info to object file
- --forget-inc-paths Forget include search paths
- --help Help (this text)
- --include-dir dir Set an include directory search path
- --register-space b Set space available for register variables
- --register-vars Enable register variables
- --rodata-name seg Set the name of the RODATA segment
- --signed-chars Default characters are signed
- --standard std Language standard (c89, c99, cc65)
- --static-locals Make local variables static
- --target sys Set the target system
- --verbose Increase verbosity
- --version Print the compiler version number
- --writable-strings Make string literals writable
+ --add-source Include source as comment
+ --all-cdecl Make functions default to __cdecl__
+ --bss-name seg Set the name of the BSS segment
+ --check-stack Generate stack overflow checks
+ --code-name seg Set the name of the CODE segment
+ --codesize x Accept larger code by factor x
+ --cpu type Set cpu type (6502, 65c02)
+ --create-dep name Create a make dependency file
+ --create-full-dep name Create a full make dependency file
+ --data-name seg Set the name of the DATA segment
+ --debug Debug mode
+ --debug-info Add debug info to object file
+ --debug-opt name Debug optimization steps
+ --dep-target target Use this dependency target
+ --disable-opt name Disable an optimization step
+ --eagerly-inline-funcs Eagerly inline some known functions
+ --enable-opt name Enable an optimization step
+ --help Help (this text)
+ --include-dir dir Set an include directory search path
+ --inline-stdfuncs Inline some standard functions
+ --list-opt-steps List all optimizer steps and exit
+ --list-warnings List available warning types for -W
+ --local-strings Emit string literals immediately
+ --memory-model model Set the memory model
+ --register-space b Set space available for register variables
+ --register-vars Enable register variables
+ --rodata-name seg Set the name of the RODATA segment
+ --signed-chars Default characters are signed
+ --standard std Language standard (c89, c99, cc65)
+ --static-locals Make local variables static
+ --target sys Set the target system
+ --verbose Increase verbosity
+ --version Print the compiler version number
+ --writable-strings Make string literals writable
---------------------------------------------------------------------------
</verb></tscreen>
<descrip>
+ <tag><tt>--all-cdecl</tt></tag>
+
+ Tells the compiler that functions which aren't declared explicitly with
+ either the <tt/__cdecl__/ or <tt/__fastcall__/ calling conventions should
+ have the cdecl convention. (Normally, functions that aren't variadic are
+ fast-called.)
+
+
+ <label id="option-bss-name">
<tag><tt>--bss-name seg</tt></tag>
- Set the name of the bss segment.
+ Set the name of the bss segment. See also <tt/<ref id="pragma-bss-name"
+ name="#pragma bss-name">/.
+ <label id="option-check-stack">
<tag><tt>--check-stack</tt></tag>
Tells the compiler to generate code that checks for stack overflows. See
- <tt><ref id="pragma-checkstack" name="#pragma checkstack"></tt> for an
+ <tt/<ref id="pragma-check-stack" name="#pragma check-stack">/ for an
explanation of this feature.
+ <label id="option-code-name">
<tag><tt>--code-name seg</tt></tag>
- Set the name of the code segment.
+ Set the name of the code segment. See also <tt/<ref id="pragma-code-name"
+ name="#pragma code-name">/
<label id="option-codesize">
This options allows finer control about speed vs. size decisions in the code
generation and optimization phases. It gives the allowed size increase
factor (in percent). The default is 100 when not using <tt/-Oi/ and 200 when
- using <tt/-Oi/ (<tt/-Oi/ is the same as <tt/--codesize 200/).
+ using <tt/-Oi/ (<tt/-Oi/ is the same as <tt/-O --codesize 200/).
+ <label id="option--cpu">
<tag><tt>--cpu CPU</tt></tag>
- A new, still experimental option. You may specify "6502" or "65C02" as
- the CPU. 6502 is the default, so this will not change anything.
- Specifying 65C02 will use a few 65C02 instructions when generating code.
- Don't expect too much from this option: It is still new (and may have
- bugs), and the additional instructions for the 65C02 are not that
- overwhelming.
+ Set the CPU, the compiler generates code for. You may specify "6502" or
+ "65C02" as the CPU. The default depends on the selected target (see option
+ <tt/<ref id="option-t" name="-t">/). It is the 6502 CPU for most targets or
+ if no target has been set. Specifying 65C02 will use a few 65C02
+ instructions when generating code. Don't expect too much from this option:
+ In most cases the difference in size and speed is just 1-2%.
+
+
+ <label id="option-create-dep">
+ <tag><tt>--create-dep name</tt></tag>
+
+ Tells the compiler to generate a file containing the dependency list for the
+ compiled module in makefile syntax. The output is written to a file with the
+ given name. The output does not include system include files (in angle
+ brackets).
+
+ <label id="option-create-full-dep">
+ <tag><tt>--create-full-dep name</tt></tag>
- <tag><tt>--create-dep</tt></tag>
+ Tells the compiler to generate a file containing the dependency list for the
+ compiled module in makefile syntax. The output is written to a file with the
+ given name. The output does include system include files (in angle
+ brackets).
- Tells the compiler to generate a file containing the dependency list for
- the compiled module in makefile syntax. The file is named as the C input
- file with the extension replaced by <tt/.u/.
+
+ <label id="option-data-name">
+ <tag><tt>--data-name seg</tt></tag>
+
+ Set the name of the data segment. See also <tt/<ref id="pragma-data-name"
+ name="#pragma data-name">/
<tag><tt>-d, --debug</tt></tag>
mortals:-)
- <tag><tt>-D sym[=definition]</tt></tag>
+ <label id="option-dep-target">
+ <tag><tt>--dep-target target</tt></tag>
- Define a macro on the command line. If no definition is given, the macro
- is defined to the value "1".
+ When generating a dependency file, don't use the actual output file as the
+ target of the dependency, but the file specified with this option. The
+ option has no effect if neither <tt/<ref id="option-create-dep"
+ name="--create-dep">/ nor <tt/<ref id="option-create-full-dep"
+ name="--create-full-dep">/ is specified.
- <tag><tt>--forget-inc-paths</tt></tag>
+ <tag><tt>-D sym[=definition]</tt></tag>
- Forget the builtin include paths. This is most useful when building
- customized C or runtime libraries, in which case the standard header
- files should be ignored.
+ Define a macro on the command line. If no definition is given, the macro
+ is defined to the value "1".
<tag><tt>-g, --debug-info</tt></tag>
symbols in a special section in the object file.
+ <label id="option-eagerly-inline-funcs">
+ <tag><tt>--eagerly-inline-funcs</tt></tag>
+
+ Have the compiler eagerly inline these functions from the C library:
+ <itemize>
+ <item><tt/memcpy()/
+ <item><tt/memset()/
+ <item><tt/strcmp()/
+ <item><tt/strcpy()/
+ <item><tt/strlen()/
+ <item>most of the functions declared in <tt/<ctype.h>/
+ </itemize>
+
+ Note: This has two consequences:
+ <itemize>
+ <item>You may not use names of standard C functions for your own functions.
+ If you do that, your program is not standard-compliant anyway; but,
+ using <tt/--eagerly-inline-funcs/ actually will break things.
+ <p>
+ <item>The inlined string and memory functions will not handle strings or
+ memory areas larger than 255 bytes. Similarly, the inlined <tt/is..()/
+ functions will not work with values outside the char. range (such as
+ <tt/EOF/).
+ <p>
+ </itemize>
+
+ <tt/--eagerly-inline-funcs/ implies the <tt><ref id="option-inline-stdfuncs"
+ name="--inline-stdfuncs"></tt> command line option.
+
+ See also <tt><ref id="pragma-allow-eager-inline" name="#pragma allow-eager-inline"></tt>.
+
+
<tag><tt>-h, --help</tt></tag>
Print the short option summary shown above.
+ <label id="option-inline-stdfuncs">
+ <tag><tt>--inline-stdfuncs</tt></tag>
+
+ Allow the compiler to inline some standard functions from the C library like
+ strlen. This will not only remove the overhead for a function call, but will
+ make the code visible for the optimizer. See also the <tt><ref id="option-O"
+ name="-Os"></tt> command line option and <tt><ref id="pragma-inline-stdfuncs"
+ name="#pragma inline-stdfuncs"></tt>.
+
+
+ <label id="option-list-warnings">
+ <tag><tt>--list-warnings</tt></tag>
+
+ List the names of warning types available for use with <tt><ref
+ id="option-W" name="-W"></tt>.
+
+
+ <label id="option-local-strings">
+ <tag><tt>--local-strings</tt></tag>
+
+ Emit string literals into the rodata segment as soon as they're encountered
+ in the source (even if you do nothing but get the sizeof those strings). The
+ default is to keep string literals until end of assembly, merge read only
+ literals if possible, and then output the literals into the data or rodata
+ segment that is active at that point. Use of this option prevents merging of
+ duplicate strings, but the options that change the name of one of the data
+ segments will work.
+
+ You can also use <tt><ref id="pragma-local-strings"
+ name="#pragma local-strings"></tt> for fine grained control.
+
+
<tag><tt>-o name</tt></tag>
Specify the name of the output file. If you don't specify a name, the
name of the C input file is used, with the extension replaced by ".s".
+ <label id="option-register-vars">
<tag><tt>-r, --register-vars</tt></tag>
<tt/-r/ will make the compiler honor the <tt/register/ keyword. Local
variables are of limited use without the optimizer, there is also a combined
switch: <tt/-Or/ will enable both, the optimizer and register variables.
- For more information about register variables see <ref id="regvars"
+ For more information about register variables see <ref id="register-vars"
name="register variables">.
The compiler setting can also be changed within the source file by using
- <tt><ref id="pragma-regvars" name="#pragma regvars"></tt>.
+ <tt/<ref id="pragma-register-vars" name="#pragma register-vars">/.
+ <label id="option-register-space">
<tag><tt>--register-space</tt></tag>
This option takes a numeric parameter and is used to specify, how much
If you don't know what all this means, please don't use this option.
+ <label id="option-rodata-name">
<tag><tt>--rodata-name seg</tt></tag>
Set the name of the rodata segment (the segment used for readonly data).
+ See also <tt/<ref id="pragma-rodata-name" name="#pragma rodata-name">/
-
+ <label id="option-signed-chars">
<tag><tt>-j, --signed-chars</tt></tag>
Using this option, you can make the default characters signed. Since the
6502 has no provisions for sign extending characters (which is needed on
almost any load operation), this will make the code larger and slower. A
better way is to declare characters explicitly as "signed" if needed. You
- can also use <tt><ref id="pragma-signedchars"
- name="#pragma signedchars"></tt> for better control of this option.
+ can also use <tt><ref id="pragma-signed-chars"
+ name="#pragma signed-chars"></tt> for better control of this option.
<label id="option--standard">
This option allows to set the language standard supported. The argument is
one of
- <itemize>
- <item>c89
- <item>c99
- <item>cc65
- </itemize>
-
- Please note that the compiler does not support the c99 standard and never
- will. c99 mode is actually c89 mode with a few selected c99 extensions
- (// comments for example).
-
-
+ <descrip>
+ <tag/c89/
+ This disables anything that is illegal in C89/C90. Among those things
+ are <tt>//</tt> comments and the non-standard keywords without
+ underscores. Please note that cc65 is not a fully C89 compliant compiler
+ despite this option. A few more things (like floats) are missing.
+
+ <tag/c99/
+ This enables a few features from the C99 standard. With this option,
+ <tt>//</tt> comments are allowed. It will also cause warnings and even
+ errors in a few situations that are allowed with <tt/--standard c89/.
+ For example, a call to a function without a prototype is an error in
+ this mode.
+
+ <tag/cc65/
+ This is the default mode. It is like c99 mode, but additional features
+ are enabled. Among these are "void data", non-standard keywords without
+ the underlines, unnamed function parameters and the requirement for
+ main() to return an int.
+ </descrip>
+
+ Please note that the compiler does not support the C99 standard and never
+ will. c99 mode is actually c89 mode with a few selected C99 extensions.
+
+
+ <label id="option-t">
<tag><tt>-t target, --target target</tt></tag>
- This option is used to set the target system. The target system
- determines things like the character set that is used for strings and
- character constants. The following target systems are supported:
+ This option is used to set the target system. The target system determines
+ the character set that is used for strings and character constants and the
+ default CPU. The CPU setting can be overriden by use of the <tt/<ref
+ id="option--cpu" name="--cpu">/ option.
+
+ The following target systems are supported:
<itemize>
<item>none
<item>apple2
<item>apple2enh
<item>atari
+ <item>atarixl
<item>atmos
<item>c16 (works also for the c116 with memory up to 32K)
<item>c64
<item>c128
<item>cbm510 (CBM-II series with 40 column video)
<item>cbm610 (all CBM-II II computers with 80 column video)
- <item>geos
+ <item>geos-apple
+ <item>geos-cbm
<item>lunix
<item>lynx
<item>nes
+ <item>osic1p
<item>pet (all CBM PET systems except the 2001)
<item>plus4
+ <item>sim6502
+ <item>sim65c02
<item>supervision
+ <item>telestrat
<item>vic20
</itemize>
or warnings are encountered.
+ <label id="option-writable-strings">
<tag><tt>--writable-strings</tt></tag>
Make string literals writable by placing them into the data segment instead
- of the rodata segment.
+ of the rodata segment. You can also use <tt><ref id="pragma-writable-strings"
+ name="#pragma writable-strings"></tt> to control this option from within
+ the source file.
+ <label id="option-static-locals">
<tag><tt>-Cl, --static-locals</tt></tag>
Use static storage for local variables instead of storage on the stack.
using
<tscreen><verb>
- void f (void)
- {
- unsigned a = 1;
- ...
- }
+ void f (void)
+ {
+ unsigned a = 1;
+ ...
+ }
</verb></tscreen>
the variable <tt/a/ will always have the value <tt/1/ when entering the
function and using <tt/-Cl/, while in
<tscreen><verb>
- void f (void)
- {
- static unsigned a = 1;
- ....
- }
+ void f (void)
+ {
+ static unsigned a = 1;
+ ....
+ }
</verb></tscreen>
the variable <tt/a/ will have the value <tt/1/ only the first time that the
function is entered, and will keep the old value from one call of the
function to the next.
- You may also use <tt><ref id="pragma-staticlocals"
- name="#pragma staticlocals"></tt> to change this setting in your
+ You may also use <tt><ref id="pragma-static-locals"
+ name="#pragma static-locals"></tt> to change this setting in your
sources.
+ <label id="option-include-dir">
<tag><tt>-I dir, --include-dir dir</tt></tag>
Set a directory where the compiler searches for include files. You may
runtime functions would have been called, even if the generated code is
larger. This will not only remove the overhead for a function call, but will
make the code visible for the optimizer. <tt/-Oi/ is an alias for
- <tt/--codesize 200/.
+ <tt/-O --codesize 200/.
<tt/-Or/ will make the compiler honor the <tt/register/ keyword. Local
variables may be placed in registers (which are actually zero page
- locations). There is some overhead involved with register variables, since
- the old contents of the registers must be saved and restored. In addition,
- the current implementation does not make good use of register variables, so
- using <tt/-Or/ may make your program even slower and larger. Use with care!
+ locations). See also the <tt/<ref id="option-register-vars"
+ name="--register-vars">/ command line option, and the <ref
+ id="register-vars" name="discussion of register variables"> below.
+
+ Using <tt/-Os/ will allow the compiler to inline some standard functions
+ from the C library like strlen. This will not only remove the overhead
+ for a function call, but will make the code visible for the optimizer.
+ See also the <tt/<ref id="option-inline-stdfuncs" name="--inline-stdfuncs">/
+ command line option.
- Using <tt/-Os/ will force the compiler to inline some known functions from
- the C library like strlen. Note: This has two consequences:
- <p>
- <itemize>
- <item>You may not use names of standard C functions in your own code. If you
- do that, your program is not standard compliant anyway, but using
- <tt/-Os/ will actually break things.
- <p>
- <item>The inlined string and memory functions will not handle strings or
- memory areas larger than 255 bytes. Similarly, the inlined <tt/is..()/
- functions will not work with values outside the char. range (such as
- <tt/EOF/).
- <p>
- </itemize>
- <p>
It is possible to concatenate the modifiers for <tt/-O/. For example, to
- enable register variables and inlining of known functions, you may use
+ enable register variables and inlining of standard functions, you may use
<tt/-Ors/.
<label id="option-W">
- <tag><tt>-W</tt></tag>
-
- This option will suppress any warnings generated by the compiler. Since
- any source file may be written in a manner that it will not produce
- compiler warnings, using this option is usually not a good idea.
+ <tag><tt>-W name[,name,...]</tt></tag>
+
+ This option allows to control warnings generated by the compiler. It is
+ followed by a comma-separated list of warnings that should be enabled or
+ disabled. To disable a warning, its name is prefixed by a minus sign. If
+ no such prefix exists, or the name is prefixed by a plus sign, the warning
+ is enabled.
+
+ The following warning names currently are recognized:
+ <descrip>
+ <tag><tt/const-comparison/</tag>
+ Warn if the result of a comparison is constant.
+ <tag><tt/error/</tag>
+ Treat all warnings as errors.
+ <tag><tt/no-effect/</tag>
+ Warn about statements that don't have an effect.
+ <tag><tt/remap-zero/</tag>
+ Warn about a <tt/<ref id="pragma-charmap" name="#pragma charmap()">/
+ that changes a character's code number from/to 0x00.
+ <tag><tt/struct-param/</tag>
+ Warn when passing structs by value.
+ <tag><tt/unknown-pragma/</tag>
+ Warn about #pragmas that aren't recognized by cc65.
+ <tag><tt/unused-label/</tag>
+ Warn about unused labels.
+ <tag><tt/unused-param/</tag>
+ Warn about unused function parameters.
+ <tag><tt/unused-var/</tag>
+ Warn about unused variables.
+ </descrip>
+
+ The full list of available warning names can be retrieved by using the
+ option <tt><ref id="option-list-warnings" name="--list-warnings"></tt>.
+
+ You may use also <tt><ref id="pragma-warn" name="#pragma warn"></tt> to
+ control this setting, for smaller pieces of code, from within your sources.
</descrip><p>
+
<sect>Input and output<p>
The compiler will accept one C file per invocation and create a file with
the same base name, but with the extension replaced by ".s". The output
-file contains assembler code suitable for the use with the ca65 macro
+file contains assembler code suitable for use with the ca65 macro
assembler.
-In addition to the paths named in the <tt/-I/ option on the command line, the
-directory named in the environment variable <tt/CC65_INC/ is added to the
-search path for include files on startup.
+Include files in quotes are searched in the following places:
+<enum>
+<item>The current file's directory.
+<item>Any directory added with the <tt/-I/ option on the command line.
+<item>The value of the environment variable <tt/CC65_INC/ if it is defined.
+</enum>
+
+Include files in angle brackets are searched in the following places:
+<enum>
+<item>Any directory added with the <tt/-I/ option on the command line.
+<item>The value of the environment variable <tt/CC65_INC/ if it is defined.
+<item>A subdirectory named <tt/include/ of the directory defined in the
+ environment variable <tt/CC65_HOME/, if it is defined.
+<item>An optionally compiled-in directory.
+</enum>
<itemize>
-<item> The datatypes "float" and "double" are not available.
- <p>
-<item> C Functions may not return structs (or unions), and structs may not
+<item> The datatypes "float" and "double" are not available.
+<item> C Functions may not return structs (or unions), and structs may not
be passed as parameters by value. However, struct assignment *is*
- possible.
- <p>
-<item> Part of the C library is available only with fastcall calling
- conventions (see below). It means that you must not mix pointers to
- those functions with pointers to user-written, not-fastcall functions.
- <p>
+ possible.
+ <p>
+<item> Most of the C library is available with only the fastcall calling
+ convention (<ref id="extension-fastcall" name="see below">). It means
+ that you must not mix pointers to those functions with pointers to
+ user-written, cdecl functions (the calling conventions are incompatible).
+ <p>
+<item> The <tt/volatile/ keyword has almost no effect. That is not as bad
+ as it sounds, since the 6502 has so few registers that it isn't
+ possible to keep values in registers anyway.
+ <p>
</itemize>
There may be some more minor differences I'm currently not aware of. The
<itemize>
-<item> The compiler allows to insert assembler statements into the output
- file. The syntax is
-
- <tscreen><verb>
- asm (<string literal>[, optional parameters]) ;
- </verb></tscreen>
- or
- <tscreen><verb>
- __asm__ (<string literal>[, optional parameters]) ;
- </verb></tscreen>
-
- The first form is in the user namespace and is disabled if the <tt/-A/
- switch is given.
-
- There is a whole section covering inline assembler statements,
- <ref id="inline-asm" name="see there">.
- <p>
-
-<item> There is a special calling convention named "fastcall".
- The syntax for a function declaration using fastcall is
-
- <tscreen><verb>
- <return type> fastcall <function name> (<parameter list>)
- </verb></tscreen>
- or
- <tscreen><verb>
- <return type> __fastcall__ <function name> (<parameter list>)
- </verb></tscreen>
- An example would be
- <tscreen><verb>
- void __fastcall__ f (unsigned char c)
- </verb></tscreen>
- The first form of the fastcall keyword is in the user namespace and can
- therefore be disabled with the <tt><ref id="option--standard"
+<item> The compiler allows to insert assembler statements into the output
+ file. The syntax is
+
+ <tscreen><verb>
+ asm [optional volatile] (<string literal>[, optional parameters]) ;
+ </verb></tscreen>
+ or
+ <tscreen><verb>
+ __asm__ [optional volatile] (<string literal>[, optional parameters]) ;
+ </verb></tscreen>
+
+ The first form is in the user namespace; and, is disabled if the <tt/-A/
+ switch is given.
+
+ There is a whole section covering inline assembler statements,
+ <ref id="inline-asm" name="see there">.
+ <p>
+
+<label id="extension-fastcall">
+<item> The normal calling convention -- for non-variadic functions -- is
+ named "fastcall". The syntax for a function declaration that
+ <em/explicitly/ uses fastcall is
+
+ <tscreen><verb>
+ <return type> fastcall <function name> (<parameter list>)
+ </verb></tscreen>
+ or
+ <tscreen><verb>
+ <return type> __fastcall__ <function name> (<parameter list>)
+ </verb></tscreen>
+ An example is
+ <tscreen><verb>
+ void __fastcall__ f (unsigned char c)
+ </verb></tscreen>
+ The first form of the fastcall keyword is in the user namespace and can
+ therefore be disabled with the <tt><ref id="option--standard"
name="--standard"></tt> command line option.
- For functions declared as <tt/fastcall/, the rightmost parameter is not
- pushed on the stack but left in the primary register when the function
- is called. This will reduce the cost when calling assembler functions
- significantly, especially when the function itself is rather small.
- <p>
-
-<item> There are two pseudo variables named <tt/__AX__/ and <tt/__EAX__/.
- Both refer to the primary register that is used by the compiler to
- evaluate expressions or return function results. <tt/__AX__/ is of
- type <tt/unsigned int/ and <tt/__EAX__/ of type <tt/long unsigned int/
- respectively. The pseudo variables may be used as lvalue and rvalue as
- every other variable. They are most useful together with short
- sequences of assembler code. For example, the macro
-
- <tscreen><verb>
- #define hi(x) \
+ For functions that are <tt/fastcall/, the rightmost parameter is not
+ pushed on the stack but left in the primary register when the function
+ is called. That significantly reduces the cost of calling those functions.
+ <p>
+
+<item> There is another calling convention named "cdecl". Variadic functions
+ (their prototypes have an ellipsis [<tt/.../]) always use that
+ convention. The syntax for a function declaration using cdecl is
+
+ <tscreen><verb>
+ <return type> cdecl <function name> (<parameter list>)
+ </verb></tscreen>
+ or
+ <tscreen><verb>
+ <return type> __cdecl__ <function name> (<parameter list>)
+ </verb></tscreen>
+ An example is
+ <tscreen><verb>
+ int* __cdecl__ f (unsigned char c)
+ </verb></tscreen>
+
+ The first form of the cdecl keyword is in the user namespace;
+ and therefore, can be disabled with the <tt/<ref id="option--standard"
+ name="--standard">/ command-line option.
+
+ For functions that are <tt/cdecl/, the rightmost parameter is pushed
+ onto the stack before the function is called. That increases the cost
+ of calling those functions, especially when they are called from many
+ places.
+ <p>
+
+<item> There are two pseudo variables named <tt/__AX__/ and <tt/__EAX__/.
+ Both refer to the primary register that is used by the compiler to
+ evaluate expressions or return function results. <tt/__AX__/ is of
+ type <tt/unsigned int/ and <tt/__EAX__/ of type <tt/long unsigned int/
+ respectively. The pseudo variables may be used as lvalue and rvalue as
+ every other variable. They are most useful together with short
+ sequences of assembler code. For example, the macro
+
+ <tscreen><verb>
+ #define hi(x) \
(__AX__ = (x), \
asm ("txa"), \
asm ("ldx #$00"), \
__AX__)
- </verb></tscreen>
+ </verb></tscreen>
+
+ will give the high byte of any unsigned value.
+ <p>
+
+<item> Inside a function, the identifier <tt/__func__/ gives the name of the
+ current function as a string. Outside of functions, <tt/__func__/ is
+ undefined.
+ Example:
- will give the high byte of any unsigned value.
- <p>
+ <tscreen><verb>
+ #define PRINT_DEBUG(s) printf ("%s: %s\n", __func__, s);
+ </verb></tscreen>
-<item> Inside a function, the identifier <tt/__func__/ gives the name of the
- current function as a string. Outside of functions, <tt/__func__/ is
- undefined.
- Example:
+ The macro will print the name of the current function plus a given
+ string.
+ <p>
- <tscreen><verb>
- #define PRINT_DEBUG(s) printf ("%s: %s\n", __func__, s);
- </verb></tscreen>
+<item> cc65 allows the initialization of <tt/void/ variables. This may be
+ used to create arbitrary structures that are more compatible with
+ interfaces written for assembler languages. Here is an example:
- The macro will print the name of the current function plus a given
- string.
- <p>
+ <tscreen><verb>
+ void GCmd = { (char)3, (unsigned)0x2000, (unsigned)0x3000 };
+ </verb></tscreen>
-<item> cc65 allows the initialization of <tt/void/ variables. This may be
- used to create variable structures that are more compatible with
- interfaces written for assembler languages. Here is an example:
+ That will be translated as follows:
- <tscreen><verb>
- void GCmd = { (char)3, (unsigned)0x2000, (unsigned)0x3000 };
- </verb></tscreen>
+ <tscreen><verb>
+ _GCmd:
+ .byte 3
+ .word $2000
+ .word $3000
+ </verb></tscreen>
- This will be translated as follows:
+ Since the variable is of type <tt/void/, you may not use it as-is.
+ However, taking the address of the variable results in a <tt/void*/
+ which may be passed to any function expecting a pointer. Also, the
+ <tt/sizeof/ operator will give the length of the initializer:
- <tscreen><verb>
- _GCmd:
- .byte 3
- .word $2000
- .word $3000
- </verb></tscreen>
+ <tscreen><verb>
+ GLen = sizeof GCmd;
+ </verb></tscreen>
- Since the variable is of type <tt/void/ you may not use it as is.
- However, taking the address of the variable results in a <tt/void*/
- which may be passed to any function expecting a pointer.
+ will assign the value 5 to <tt/GLen/.
- See the <url url="geos.html" name="GEOS library document"> for examples
- on how to use this feature.
- <p>
+ See the <url url="geos.html" name="GEOS library document"> for examples
+ on how to use that feature.
<item> cc65 implements flexible array struct members as defined in the C99 ISO
standard. As an extension, these fields may be initialized. There are
size zero, even if it is initialized.
<p>
+<item> Computed gotos, a GCC extension, has limited support. With it you can
+ use fast jump tables from C. You can take the address of a label with
+ a double ampersand, putting them in a static const array of type void *.
+ Then you can jump to one of these labels as follows:
+
+ <tscreen><verb>
+ static const void * const jumptable[] = {
+ &&add,
+ &&sub
+ };
+ goto *jumptable[somevar];
+
+ add:
+ ...code...
+ </verb></tscreen>
+
+ In the jump table, no expressions are supported. The array index
+ used in the goto must be a simple variable or a constant.
+
</itemize>
<p>
+
<sect>Predefined macros<p>
The compiler defines several macros at startup:
<descrip>
-
- <tag><tt>__CC65__</tt></tag>
-
- This macro is always defined. Its value is the version number of the
- compiler in hex. For example, version 2.10.1 of the compiler has this macro
- defined as <tt/0x02A1/.
-
<tag><tt>__APPLE2__</tt></tag>
- This macro is defined if the target is the Apple ][ (-t apple2).
+ This macro is defined if the target is the Apple ][ (-t apple2) or the enhanced Apple //e (-t apple2enh).
<tag><tt>__APPLE2ENH__</tt></tag>
This macro is defined if the target is the enhanced Apple //e (-t apple2enh).
+ <tag><tt>__ATARI2600__</tt></tag>
+
+ This macro is defined if the target is the Atari 2600 game console.
+
+ <tag><tt>__ATARI5200__</tt></tag>
+
+ This macro is defined if the target is the Atari 5200 game console.
+
<tag><tt>__ATARI__</tt></tag>
- This macro is defined if the target is one of the Atari computers
- (400/800/130XL/800XL).
+ This macro is defined if the target is the Atari 400/800 (-t atari) or the Atari 800XL/130XE (-t atarixl).
+
+ <tag><tt>__ATARIXL__</tt></tag>
+
+ This macro is defined if the target is the Atari 800XL/130XE (-t atarixl).
<tag><tt>__ATMOS__</tt></tag>
This macro is defined if the target is the Oric Atmos (-t atmos).
- <tag><tt>__CBM__</tt></tag>
+ <tag><tt>__C128__</tt></tag>
- This macro is defined if the target system is one of the CBM targets.
+ This macro is defined if the target is the Commodore 128 (-t c128).
<tag><tt>__C16__</tt></tag>
- This macro is defined if the target is the c16 (-t c16).
+ This macro is defined if the target is the Commodore 16/116 (-t c16) or the Commodore Plus/4 (-t plus4).
<tag><tt>__C64__</tt></tag>
- This macro is defined if the target is the c64 (-t c64).
+ This macro is defined if the target is the Commodore 64 (-t c64).
- <tag><tt>__C128__</tt></tag>
+ <tag><tt>__CBM__</tt></tag>
- This macro is defined if the target is the c128 (-t c128).
+ This macro is defined if the target system is one of the CBM targets.
<tag><tt>__CBM510__</tt></tag>
This macro is defined if the target is one of the CBM 600/700 family of
computers (called B series in the US).
- <tag><tt>__GEOS__</tt></tag>
-
- This macro is defined if you are compiling for the GEOS system (-t geos).
-
- <tag><tt>__LUNIX__</tt></tag>
+ <tag><tt>__CC65__</tt></tag>
- This macro is defined if you are compiling for the LUnix system (-t lunix).
+ This macro is always defined. Its value is the version number of the
+ compiler in hex. For example, version 2.14 of the compiler has this macro
+ defined as <tt/0x02E0/.
- <tag><tt>__LYNX__</tt></tag>
+ <tag><tt>__CC65_STD__</tt></tag>
- This macro is defined if the target is the Atari Lynx (-t lynx).
+ This macro is defined to one of the following depending on the <tt><ref
+ id="option--standard" name="--standard"></tt> command line option:
+ <itemize>
+ <item><tt/__CC65_STD_C89__/
+ <item><tt/__CC65_STD_C99__/
+ <item><tt/__CC65_STD_CC65__/
+ </itemize>
- <tag><tt>__NES__</tt></tag>
+ <tag><tt>__DATE__</tt></tag>
- This macro is defined if the target is the NES (-t nes).
+ This macro expands to the date of translation of the preprocessing
+ translation unit in the form "Mmm dd yyyy".
- <tag><tt>__PET__</tt></tag>
+ <tag><tt>__EAGERLY_INLINE_FUNCS__</tt></tag>
- This macro is defined if the target is the PET family of computers (-t pet).
+ Is defined if the compiler was called with the <tt><ref id="option-eagerly-inline-funcs"
+ name="--eagerly-inline-funcs"></tt> command line option.
- <tag><tt>__PLUS4__</tt></tag>
+ <tag><tt>__FILE__</tt></tag>
- This macro is defined if the target is the plus/4 (-t plus4).
+ This macro expands to a string containing the name of the C source file.
- <tag><tt>__SUPERVISION__</tt></tag>
+ <tag><tt>__GEOS__</tt></tag>
- This macro is defined if the target is the supervision (-t supervision).
+ This macro is defined if you are compiling for one of the GEOS systems.
- <tag><tt>__VIC20__</tt></tag>
+ <tag><tt>__GEOS_APPLE__</tt></tag>
- This macro is defined if the target is the vic20 (-t vic20).
+ This macro is defined if you are compiling for the Apple GEOS system (-t geos-apple).
- <tag><tt>__FILE__</tt></tag>
+ <tag><tt>__GEOS_CBM__</tt></tag>
- This macro expands to a string containing the name of the C source file.
+ This macro is defined if you are compiling for the GEOS 64/128 system (-t geos-cbm).
<tag><tt>__LINE__</tt></tag>
This macro expands to the current line number.
- <tag><tt>__CC65_STD__</tt></tag>
+ <tag><tt>__LUNIX__</tt></tag>
- This macro is defined to one of the following depending on the <tt><ref
- id="option--standard" name="--standard"></tt> command line option:
- <itemize>
- <item><tt/__CC65_STD_C89__/
- <item><tt/__CC65_STD_C99__/
- <item><tt/__CC65_STD_CC65__/
- </itemize>
+ This macro is defined if you are compiling for the LUnix system (-t lunix).
+
+ <tag><tt>__LYNX__</tt></tag>
+
+ This macro is defined if the target is the Atari Lynx (-t lynx).
+
+ <tag><tt>__NES__</tt></tag>
+
+ This macro is defined if the target is the Nintendo Entertainment System (-t nes).
<tag><tt>__OPT__</tt></tag>
Is defined if the compiler was called with the <tt/-Os/ command line option.
+ <tag><tt>__OSIC1P__</tt></tag>
+
+ This macro is defined if the target is the Ohio Scientific Challenger 1P
+ (-t osic1p).
+
+ <tag><tt>__PET__</tt></tag>
+
+ This macro is defined if the target is the PET family of computers (-t pet).
+
+ <tag><tt>__PLUS4__</tt></tag>
+
+ This macro is defined if the target is the Commodore Plus/4 (-t plus4).
+
+ <tag><tt>__STDC_HOSTED__</tt></tag>
+
+ This macro is expands to the integer constant 1.
+
+ <tag><tt>__SIM6502__</tt></tag>
+
+ This macro is defined if the target is sim65 in 6502 mode (-t sim6502).
+
+ <tag><tt>__SIM65C02__</tt></tag>
+ This macro is defined if the target is sim65 in 65C02 mode (-t sim65c02).
+
+ <tag><tt>__SUPERVISION__</tt></tag>
+
+ This macro is defined if the target is the Supervision (-t supervision).
+
+ <tag><tt>__TELESTRAT__</tt></tag>
+
+ This macro is defined if the target is the Telestrat (-t telestrat).
+
+ <tag><tt>__TIME__</tt></tag>
+
+ This macro expands to the time of translation of the preprocessing
+ translation unit in the form "hh:mm:ss".
+
+ <tag><tt>__VIC20__</tt></tag>
+
+ This macro is defined if the target is the Commodore VIC20 (-t vic20).
</descrip>
+
<sect>#pragmas<label id="pragmas"><p>
The compiler understands some pragmas that may be used to change code
before changing it. The value may later be restored by using the <tt/pop/
parameter with the <tt/#pragma/.
-<sect1><tt>#pragma bssseg ([push,]<name>)</tt><p>
+
+<sect1><tt>#pragma allow-eager-inline ([push,] on|off)</tt><label id="pragma-allow-eager-inline"><p>
+
+ Allow eager inlining of known functions. If the argument is "off", eager
+ inlining is disabled, otherwise it is enabled. Please note that (in contrast
+ to the <tt><ref id="option-eagerly-inline-funcs" name="--eagerly-inline-funcs"></tt>
+ command line option) this pragma does not imply the <tt><ref id="option-inline-stdfuncs"
+ name="--inline-stdfuncs"></tt> command line option. Rather it marks code to be safe for
+ eager inlining of known functions if inlining of standard functions is enabled.
+
+ The <tt/#pragma/ understands the push and pop parameters as explained above.
+
+
+<sect1><tt>#pragma bss-name ([push,] <name>)</tt><label id="pragma-bss-name"><p>
This pragma changes the name used for the BSS segment (the BSS segment
is used to store uninitialized data). The argument is a string enclosed
Example:
<tscreen><verb>
- #pragma bssseg ("MyBSS")
+ #pragma bss-name ("MyBSS")
</verb></tscreen>
-<sect1><tt>#pragma charmap (<index>, <code>)</tt><p>
+<sect1><tt>#pragma charmap (<index>, <code>)</tt><label id="pragma-charmap"><p>
Each literal string and each literal character in the source is translated
- by use of a translation table. This translation table is preset when the
- compiler is started depending on the target system, for example to map
- ISO-8859-1 characters into PETSCII if the target is a commodore machine.
+ by use of a translation table. That translation table is preset when the
+ compiler is started, depending on the target system; for example, to map
+ ISO-8859-1 characters into PETSCII if the target is a Commodore machine.
This pragma allows to change entries in the translation table, so the
translation for individual characters, or even the complete table may be
- adjusted.
+ adjusted. Both arguments are assumed to be unsigned characters with a valid
+ range of 0-255.
- Both arguments are assumed to be unsigned characters with a valid range of
- 1-255.
-
- Beware of two pitfalls:
-
- <itemize>
- <item>The character index is actually the code of the character in the
- C source, so character mappings do always depend on the source
- character set. This means that <tt/#pragma charmap/ is not
- portable -- it depends on the build environment.
- <item>While it is possible to use character literals as indices, the
- result may be somewhat unexpected, since character literals are
- itself translated. For this reason I would suggest to avoid
- character literals and use numeric character codes instead.
- </itemize>
+ Beware of some pitfalls:
+ <itemize>
+ <item>The character index is actually the code of the character in the
+ C source; so, character mappings do always depend on the source
+ character set. That means that <tt/#pragma charmap()/ is not
+ portable -- it depends on the build environment.
+ <item>While it is possible to use character literals as indices, the
+ result may be somewhat unexpected, since character literals are
+ themselves translated. For that reason, I would suggest to avoid
+ character literals, and use numeric character codes instead.
+ <item>It is risky to change index <tt/0x00/, because string functions depend
+ on it. If it is changed, then the <tt/'\0'/ at the end of string
+ literals will become non-zero. Functions that are used on those
+ literals won't stop at the end of them. cc65 will warn you if you do
+ change that code number. You can turn off that <tt/remap-zero/ warning
+ if you are certain that you know what you are doing (see <tt/<ref
+ id="pragma-warn" name="#pragma warn()">/).
+ </itemize>
Example:
<tscreen><verb>
- /* Use a space wherever an 'a' occurs in ISO-8859-1 source */
- #pragma charmap (0x61, 0x20);
+ /* Use a space wherever an 'a' occurs in ISO-8859-1 source */
+ #pragma charmap (0x61, 0x20);
</verb></tscreen>
-<sect1><tt>#pragma check
stack ([push,]on|off)</tt><label id="pragma-checkstack"><p>
+<sect1><tt>#pragma check
-stack ([push,] on|off)</tt><label id="pragma-check-stack"><p>
Tells the compiler to insert calls to a stack checking subroutine to detect
stack overflows. The stack checking code will lead to somewhat larger and
The <tt/#pragma/ understands the push and pop parameters as explained above.
-<sect1><tt>#pragma codeseg ([push,]<name>)</tt><p>
+
+<sect1><tt>#pragma code-name ([push,] <name>)</tt><label id="pragma-code-name"><p>
This pragma changes the name used for the CODE segment (the CODE segment
is used to store executable code). The argument is a string enclosed in
Example:
<tscreen><verb>
- #pragma codeseg ("MyCODE")
+ #pragma code-name ("MyCODE")
</verb></tscreen>
-<sect1><tt>#pragma codesize ([push,]<int>)</tt><label id="pragma-codesize"><p>
+<sect1><tt>#pragma codesize ([push,]
<int>)</tt><label id="pragma-codesize"><p>
This pragma allows finer control about speed vs. size decisions in the code
generation and optimization phase. It gives the allowed size increase factor
The <tt/#pragma/ understands the push and pop parameters as explained above.
-<sect1><tt>#pragma data
seg ([push,]<name>)</tt><p>
+<sect1><tt>#pragma data
-name ([push,] <name>)</tt><label id="pragma-data-name"><p>
This pragma changes the name used for the DATA segment (the DATA segment
is used to store initialized data). The argument is a string enclosed in
Example:
<tscreen><verb>
- #pragma dataseg ("MyDATA")
+ #pragma data-name ("MyDATA")
+ </verb></tscreen>
+
+
+<sect1><tt>#pragma inline-stdfuncs ([push,] on|off)</tt><label id="pragma-inline-stdfuncs"><p>
+
+ Allow the compiler to inline some standard functions from the C library like
+ strlen. If the argument is "off", inlining is disabled, otherwise it is enabled.
+
+ See also the <tt/<ref id="option-inline-stdfuncs" name="--inline-stdfuncs">/
+ command line option.
+
+ The <tt/#pragma/ understands the push and pop parameters as explained above.
+
+
+<sect1><tt>#pragma local-strings ([push,] on|off)</tt><label id="pragma-local-strings"><p>
+
+ When "on", emit string literals to the data segment when they're encountered
+ in the source. The default ("off") is to keep string literals until end of
+ assembly, merge read only literals if possible, and then output the literals
+ into the data or rodata segment that is active at that point.
+
+ Using this <tt/#pragma/ it is possible to control the behaviour from within
+ the source. When <tt/#pragma local-strings/ is active, string literals are
+ output immediately, which means that they go into the currently active data
+ or rodata segment, but cannot be merged. When inactive, string literals are
+ remembered and output as a whole when translation is finished.
+
+
+<sect1><tt>#pragma message (<message>)</tt><label id="pragma-message"><p>
+
+ This pragma is used to display informational messages at compile-time.
+
+ The message intented to be displayed must be a string literal.
+
+ Example:
+ <tscreen><verb>
+ #pragma message ("in a bottle")
+ </verb></tscreen>
+
+ Results in the compiler outputting the following to stderr:
+ <tscreen><verb>
+ example.c(42): Note: in a bottle
</verb></tscreen>
-<sect1><tt>#pragma optimize ([push,]on|off)</tt><label id="pragma-optimize"><p>
+<sect1><tt>#pragma optimize ([push,]
on|off)</tt><label id="pragma-optimize"><p>
Switch optimization on or off. If the argument is "off", optimization is
disabled, otherwise it is enabled. Please note that this pragma only effects
The <tt/#pragma/ understands the push and pop parameters as explained above.
-<sect1><tt>#pragma rodata
seg ([push,]<name>)</tt><p>
+<sect1><tt>#pragma rodata
-name ([push,] <name>)</tt><label id="pragma-rodata-name"><p>
This pragma changes the name used for the RODATA segment (the RODATA
segment is used to store readonly data). The argument is a string
Example:
<tscreen><verb>
- #pragma rodataseg ("MyRODATA")
+ #pragma rodata-name ("MyRODATA")
</verb></tscreen>
-<sect1><tt>#pragma regvaraddr ([push,]
on|off)</tt><p>
+<sect1><tt>#pragma regvaraddr ([push,]
on|off)</tt><label id="pragma-regvaraddr"><p>
The compiler does not allow to take the address of register variables.
The regvaraddr pragma changes this. Taking the address of a register
Example:
<tscreen><verb>
- #pragma regvaraddr(on) /* Allow taking the address
- * of register variables
- */
+ #pragma regvaraddr(on) /* Allow taking the address
+ * of register variables
+ */
</verb></tscreen>
-<sect1><tt>#pragma reg
vars ([push,]on|off)</tt><label id="pragma-regvars"><p>
+<sect1><tt>#pragma reg
ister-vars ([push,] on|off)</tt><label id="pragma-register-vars"><p>
Enables or disables use of register variables. If register variables are
disabled (the default), the <tt/register/ keyword is ignored. Register
- variables are explained in more detail in <ref id="regvars" name="a separate
+ variables are explained in more detail in <ref id="register-vars" name="a separate
chapter">.
The <tt/#pragma/ understands the push and pop parameters as explained above.
-<sect1><tt>#pragma signed
chars ([push,]on|off)</tt><label id="pragma-signedchars"><p>
+<sect1><tt>#pragma signed
-chars ([push,] on|off)</tt><label id="pragma-signed-chars"><p>
Changes the signedness of the default character type. If the argument is
- "on", default characters are signed, otherwise characters are unsigned.
- The compiler default is to make characters unsigned since this creates a
- lot better code. This default may be overridden by the <tt/--signed-chars/
- command line option.
+ "on", default characters are signed, otherwise characters are unsigned. The
+ compiler default is to make characters unsigned since this creates a lot
+ better code. This default may be overridden by the <tt/<ref
+ name="--signed-chars" id="option-signed-chars">/ command line option.
The <tt/#pragma/ understands the push and pop parameters as explained above.
-<sect1><tt>#pragma static
locals ([push,]on|off)</tt><label id="pragma-staticlocals"<p>
+<sect1><tt>#pragma static
-locals ([push,] on|off)</tt><label id="pragma-static-locals"<p>
Use variables in the bss segment instead of variables on the stack. This
- pragma changes the default set by the compiler option <tt/-Cl/. If the
- argument is "on", local variables are allocated in the BSS segment,
- leading to shorter and in most cases faster, but non-reentrant code.
+ pragma changes the default set by the compiler option <tt/<ref
+ name="--static-locals" id="option-static-locals">/. If the argument is "on",
+ local variables are allocated in the BSS segment, leading to shorter and in
+ most cases faster, but non-reentrant code.
The <tt/#pragma/ understands the push and pop parameters as explained above.
-<sect1><tt>#pragma warn ([push,]on|off)</tt><label id="pragma-warn"><p>
+<sect1><tt>#pragma warn (name, [push,] on|off)</tt><label id="pragma-warn"><p>
+
+ Switch compiler warnings on or off. "name" is the name of a warning (see the
+ <tt/<ref name="-W" id="option-W">/ compiler option for a list). The name is
+ followed either by "pop", which restores the last pushed state, or by "on" or
+ "off", optionally preceeded by "push" to push the current state before
+ changing it.
+
+ Example:
+ <tscreen><verb>
+ /* Don't warn about the unused parameter in function func */
+ #pragma warn (unused-param, push, off)
+ static int func (int unused)
+ {
+ return 0;
+ }
+ #pragma warn (unused-param, pop)
+ </verb></tscreen>
+
+
+<sect1><tt>#pragma wrapped-call (push, <name>, <identifier>)</tt><label id="pragma-wrapped-call"><p>
+
+ This pragma sets a wrapper for functions, often used for trampolines.
+
+ The name is a function returning <tt/void/, and taking no parameters.
+ It must preserve the CPU's <tt/A/ and <tt/X/ registers if it wraps any
+ <tt/__fastcall__/ functions that have parameters. It must preserve
+ the <tt/Y/ register if it wraps any variadic functions (they have "<tt/.../"
+ in their prototypes).
- Switch compiler warnings on or off. If the argument is "off", warnings are
- disabled, otherwise they're enabled. The default is "on", but may be changed
- with the <tt/<ref name="-W" id="option-W">/ compiler option.
+ The identifier is an 8-bit number that's set into <tt/tmp4/.
+
+ The address of a wrapped function is passed in <tt/ptr4/. The wrapper can
+ call that function by using "<tt/jsr callptr4/".
+
+ This feature is useful, for example, with banked memory, to switch banks
+ automatically to where a wrapped function resides, and then to restore the
+ previous bank when it returns.
+
+ The <tt/#pragma/ requires the push or pop argument as explained above.
+
+ Example:
+ <tscreen><verb>
+/* Note that this code can be in a header. */
+void mytrampoline(void); /* Doesn't corrupt __AX__ */
+
+#pragma wrapped-call (push, mytrampoline, 5)
+void somefunc1(void);
+void somefunc2(int, char *);
+#pragma wrapped-call (pop)
+ </verb></tscreen>
+
+
+<sect1><tt>#pragma writable-strings ([push,] on|off)</tt><label id="pragma-writable-strings"><p>
+
+ Changes the storage location of string literals. For historical reasons,
+ the C standard defines that string literals are of type "char[]", but
+ writing to such a literal causes undefined behaviour. Most compilers
+ (including cc65) place string literals in the read-only data segment, which
+ may cause problems with old C code that writes to string literals.
+
+ Using this pragma (or the corresponding command line option <tt/<ref
+ name="--writable-strings" id="option-writable-strings">/) causes the
+ literals to be placed in the data segment so they can be written to without
+ worry.
The <tt/#pragma/ understands the push and pop parameters as explained above.
Example:
<tscreen><verb>
- extern int foo;
- #pragma zpsym ("foo"); /* foo is in the zeropage */
+ extern int foo;
+ #pragma zpsym ("foo"); /* foo is in the zeropage */
</verb></tscreen>
-
-<sect>Register variables<label id="regvars"><p>
+<sect>Register variables<label id="register-vars"><p>
The runtime for all supported platforms has 6 bytes of zero page space
available for register variables (this could be increased, but I think it's a
trouble. The only savings you get here are by the use of a zero page variable
instead of one on the stack or in the data segment.
-Register variables must be explicitly enabled by using <tt/-Or/ or <tt/-r/ on
-the command line. Register variables are only accepted on function top level,
-register variables declared in interior blocks are silently converted to
-<tt/auto/. With register variables disabled, all variables declared as
-<tt/register/ are actually auto variables.
+Register variables must be explicitly enabled, either by using <tt/<ref
+name="-Or" id="option-O">/ or <tt/<ref name="--register-vars"
+id="option-register-vars">/ on the command line or by use of <tt/<ref
+name="#pragma register-vars" id="pragma-register-vars">/. Register variables
+are only accepted on function top level, register variables declared in
+interior blocks are silently converted to <tt/auto/. With register variables
+disabled, all variables declared as <tt/register/ are actually auto variables.
Please take care when using register variables: While they are helpful and can
lead to a tremendous speedup when used correctly, improper usage will cause
syntax is
<tscreen><verb>
- asm (<string literal>[, optional parameters]) ;
+ asm [optional volatile] (<string literal>[, optional parameters]) ;
</verb></tscreen>
or
<tscreen><verb>
- __asm__ (<string literal>[, optional parameters]) ;
+ __asm__ [optional volatile] (<string literal>[, optional parameters]) ;
</verb></tscreen>
<p>
-The first form is in the user namespace and is disabled by <tt><ref
+The first form is in the user namespace; and, is disabled by <tt><ref
id="option--standard" name="--standard"></tt> if the argument is not <tt/cc65/.
-The asm statement may be used inside a function and on global file level. An
-inline assembler statement is a primary expression, so it may also be used as
-part of an expression. Please note however that the result of an expression
-containing just an inline assembler statement is always of type <tt/void/.
+The <tt/asm/ statement can be used only inside a function. Please note that
+the result of an inline assembler expression is always of type <tt/void/.
-The contents of the string literal are preparsed by the compiler and inserted
-into the generated assembly output, so that the can be further processed by
-the backend and especially the optimizer. For this reason, the compiler does
-only allow regular 6502 opcodes to be used with the inline assembler. Pseudo
-instructions (like <tt/.import/, <tt/.byte/ and so on) are <em/not/ allowed,
+The contents of the string literal are preparsed by the compiler; and, inserted
+into the generated assembly output, so that it can be processed further by
+the backend -- and, especially the optimizer. For that reason, the compiler does
+allow only regular 6502 opcodes to be used with the inline assembler. Pseudo
+instructions (like <tt/.import/, <tt/.byte/, and so on) are <em/not/ allowed,
even if the ca65 assembler (which is used to translate the generated assembler
-code) would accept them. The builtin inline assembler is not a replacement for
-the full blown macro assembler which comes with the compiler.
+code) would accept them. The built-in inline assembler is not a replacement for
+the full-blown macro assembler which comes with the compiler.
Note: Inline assembler statements are subject to all optimizations done by the
-compiler. There is currently no way to protect an inline assembler statement
-from being moved or removed completely by the optimizer. If in doubt, check
-the generated assembler output, or disable optimizations.
+compiler. There currently is no way to protect an inline assembler statement
+-- alone -- from being moved or removed completely by the optimizer. If in
+doubt, check the generated assembler output; or, disable optimizations (for
+that function).
+
+As a shortcut, you can put the <tt/volatile/ qualifier in your <tt/asm/
+statements. It will disable optimization for the functions in which those
+<tt/asm volatile/ statements sit. The effect is the same as though you put
+<tt/#pragma optimize(push, off)/ above those functions, and <tt/#pragma
+optimize(pop)/ below those functions.
The string literal may contain format specifiers from the following list. For
each format specifier, an argument is expected which is inserted instead of
-the format specifier before passing the assembly code line to the backend.
+the format specifier, before passing the assembly code line to the backend.
<itemize>
<item><tt/%b/ - Numerical 8-bit value
<item><tt/%w/ - Numerical 16-bit value
<item><tt/%l/ - Numerical 32-bit value
- <item><tt/%v/ - Assembler name of a (global) variable or function
- <item><tt/%o/ - Stack offset of a (local) variable
+ <item><tt/%v/ - Assembler name of a global variable or function
+ <item><tt/%o/ - Stack offset of a local variable
<item><tt/%g/ - Assembler name of a C label
<item><tt/%s/ - The argument is converted to a string
<item><tt/%%/ - The % sign itself
</itemize><p>
-Using these format specifiers, you can access C <tt/#defines/, variables or
+Using those format specifiers, you can access C <tt/#defines/, variables, or
similar stuff from the inline assembler. For example, to load the value of
-a C <tt/#define/ into the Y register, one would use
+a C <tt/#define/ into the Y index register, one would use
<tscreen><verb>
- #define OFFS 23
- __asm__ ("ldy #%b", OFFS);
+ #define OFFS 23
+ __asm__ ("ldy #%b", OFFS);
</verb></tscreen>
Or, to access a struct member of a static variable:
<tscreen><verb>
- typedef struct {
- unsigned char x;
- unsigned char y;
- unsigned char color;
- } pixel_t;
- static pixel_t pixel;
- __asm__ ("ldy #%b", offsetof(pixel_t, color));
- __asm__ ("lda %v,y", pixel);
+ typedef struct {
+ unsigned char x;
+ unsigned char y;
+ unsigned char color;
+ } pixel_t;
+ static pixel_t pixel;
+ __asm__ ("ldy #%b", offsetof(pixel_t, color));
+ __asm__ ("lda %v,y", pixel);
+</verb></tscreen>
+<p>
+The next example shows how to use global variables to exchange data between C
+and assembler; and, how to handle assembler jumps:
+
+<tscreen><verb>
+ static unsigned char globalSubA, globalSubB, globalSubResult;
+
+ /* return a-b, return 255 if b>a */
+ unsigned char sub (unsigned char a, unsigned char b)
+ {
+ globalSubA = a;
+ globalSubB = b;
+ __asm__ ("sec");
+ __asm__ ("lda %v", globalSubA);
+ __asm__ ("sbc %v", globalSubB);
+ __asm__ ("bcs %g", jumpSubNoError);
+ __asm__ ("lda #$FF");
+ jumpSubNoError:
+ __asm__ ("sta %v", globalSubResult);
+ return globalSubResult;
+ }
+</verb></tscreen>
+<p>
+
+Arrays also can be accessed:
+
+<tscreen><verb>
+ static const unsigned char globalSquareTable[] = {
+ 0, 1, 4, 9, 16, 25, 36, 49, 64, 81,
+ 100, 121, 144, 169, 196, 225
+ };
+ static unsigned char globalSquareA, globalSquareResult;
+
+ /* return a*a for a<16, else 255 */
+ unsigned char square (unsigned char a)
+ {
+ if (a > 15) {
+ return 255;
+ }
+ globalSquareA = a;
+ __asm__ ("ldx %v", globalSquareA);
+ __asm__ ("lda %v,x", globalSquareTable);
+ __asm__ ("sta %v", globalSquareResult);
+ return globalSquareResult;
+ }
</verb></tscreen>
<p>
Note: Do not embed the assembler labels that are used as names of global
-variables or functions into your asm statements. Code like this
+variables or functions into your <tt/asm/ statements. Code such as this:
<tscreen><verb>
int foo;
- int bar () { return 1; }
- __asm__ ("lda _foo"); /* DON'T DO THAT! */
+ int bar (void) { return 1; }
+ ...
+ __asm__ ("lda _foo"); /* DON'T DO THAT! */
...
__asm__ ("jsr _bar"); /* DON'T DO THAT EITHER! */
</verb></tscreen>
<p>
-may stop working if the way, the compiler generates these names is changed in
-a future version. Instead use the format specifiers from the table above:
+might stop working if the way that the compiler generates those names is changed in
+a future version. Instead, use the format specifiers from the table above:
<tscreen><verb>
- __asm__ ("lda %v", foo); /* OK */
+ __asm__ ("lda %v", foo); /* OK */
...
__asm__ ("jsr %v", bar); /* OK */
</verb></tscreen>
<p>
+
<sect>Implementation-defined behavior<p>
This section describes the behavior of cc65 when the standard describes the
-behavior as implementation-defined.
+behavior as implementation-defined.
(to be done)
-<sect>Bugs/Feedback<p>
-
-If you have problems using the compiler, if you find any bugs, or if you're
-doing something interesting with it, I would be glad to hear from you. Feel
-free to contact me by email (<htmlurl url="mailto:uz@cc65.org"
-name="uz@cc65.org">).
-
-
-
<sect>Copyright<p>
This is the original compiler copyright:
freely, subject to the following restrictions:
<enum>
-<item> The origin of this software must not be misrepresented; you must not
- claim that you wrote the original software. If you use this software
- in a product, an acknowledgment in the product documentation would be
- appreciated but is not required.
-<item> Altered source versions must be plainly marked as such, and must not
- be misrepresented as being the original software.
-<item> This notice may not be removed or altered from any source
- distribution.
+<item> The origin of this software must not be misrepresented; you must not
+ claim that you wrote the original software. If you use this software
+ in a product, an acknowledgment in the product documentation would be
+ appreciated but is not required.
+<item> Altered source versions must be plainly marked as such, and must not
+ be misrepresented as being the original software.
+<item> This notice may not be removed or altered from any source
+ distribution.
</enum>
</article>
-
projects / cc65 / blobdiff