mirror of https://github.com/cc65/cc65.git
250 lines
8.1 KiB
Plaintext
250 lines
8.1 KiB
Plaintext
<!doctype linuxdoc system>
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<article>
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<title>cc65 Library Overview
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<author><url url="mailto:uz@cc65.org" name="Ullrich von Bassewitz">
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<abstract>
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An overview over the runtime and C libraries that come with the cc65 compiler,
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including a discussion of the differences to the ISO standard.
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</abstract>
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<!-- Table of contents -->
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<toc>
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<!-- Begin the document -->
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<sect>Overview<p>
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This file contains a short overview of the libraries available for the cc65 C
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compiler. Please have a look at the <url url="funcref.html" name="function
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reference"> for a function-by-function list. Because the function reference is
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not complete (we're working on that), it may happen that you don't find a
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specific function. In that case, have a look into the header files. All
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functions, that are not defined by the ISO C standard, have a short comment in
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the headers, explaining their use.
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<sect>ISO C compatible library<p>
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The C library contains a large subset of the ISO C library. Functions usually
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are missing in areas where there are no support on typical 6502 systems.
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Wide-character sets are an example for that.
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I will not go into detail about the ISO functions. If a function is not
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mentioned here explicitly, expect it to be available, and to behave as defined
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in the C standard.
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Functions that are <em/not/ available:
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<itemize>
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<item><tt>tmpfile/tmpnam</tt>
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<p>
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<item><tt>system</tt> (cc65 alternative <tt>exec</tt>)
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<p>
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<item>All functions that handle floating point numbers in some manner.
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<p>
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<item>The <tt/ldiv/ function (cc65 currently is not able to return structs,
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by value, with a size not equal to 1, 2, or 4 bytes).
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<p>
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<item>All functions handling wide-character strings.
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<p>
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<item>Signals and all related functions (having <tt/SIGSEGV/ would be
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cool. :-)
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<p>
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<item><tt>setbuf/setvbuf</tt>
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</itemize>
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Functions not available on all supported systems:
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<itemize>
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<item><tt>clock</tt>: Support depends on the capabilities of the target
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machine.
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<p>
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<item><tt>fopen/fread/fwrite/fclose/fputs/fgets/fscanf</tt>: The functions
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are built on open/read/write/close. Those latter functions are not available
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on all systems.
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<p>
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<item><tt>ftell/fseek/fgetpos/fsetpos</tt>: Support depends on the
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capabilities of the target machine.
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<p>
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<item><tt>rename/remove/rewind</tt>: Support depends on the capabilities of
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the target machine.
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<p>
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<item><tt>time</tt>: Many of the supported systems don't have a real-time
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clock, which means that the <tt/time/ function is not available. Please note
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that the other functions from <tt/time.h/ <em/are/ available.
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</itemize>
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Functions that are limited in any way:
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<itemize>
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<item><tt>strcspn/strpbrk/strspn</tt>: Those functions have a length
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limitation of 256 for the second string argument. Since that string gives a
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character set, and there are only 256 distinct characters, that shouldn't be
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a problem.
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<p>
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<item><tt>getenv</tt>: Since there is no such thing as an environment on all
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supported systems, the <tt/getenv/ function always will return a <tt/NULL/
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pointer.
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<p>
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<item><tt>locale</tt>: There is no locale other than the "C" locale. The
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native locale is identical to the "C" locale.
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</itemize>
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In addition to those limitations, some more functions are limited if inlined
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versions are requested by using the <tt/-Os/ command-line option:
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<itemize>
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<item>The <tt/strlen/ function works for only strings with a maximum length
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of 255 characters.
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<p>
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<item>The <tt/isXXX/ character classification functions from
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<tt/<ctype.h>/ will give unpredictable results if the argument is not
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in character range (0..255). That limitation may be removed by #undef'ing
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the function name (when using <tt/-Os/, the functions are actually macros
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that expand to inline assembly code, but the real functions still are
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available if the macro definition is removed).
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</itemize>
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<sect>CPU-specific stuff - 6502.h<p>
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The header file 6502.h contains some functions that make sense only with the
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6502 CPU. Examples are macros to insert more or less useful instructions into
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your C code, or a function to call arbitrary machine language subroutines,
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passing registers in and out.
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<sect>Target-specific stuff<p>
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For each supported system, there's a header file that contains calls or
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defines specific for that system. So, when programming for the C64, include
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<tt/<c64.h>/, for the C128, include <tt/<c128.h>/, and so on.
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To make the task for the Commodore systems easier, there is also a header file
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named <tt/<cbm.h>/ that will define stuff common for all CBM systems,
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and include the header file for the specific target system.
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The header files contain
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<itemize>
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<item>Defines for special keys (such as function keys)
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<item>Defines for special characters (such as the graphics characters)
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<item>Variables with a fixed address in memory that may be used to access
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special hardware. For the C64 and C128, there is a variable struct named
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<tt/SID/. Writing to the fields of that struct will write to the SID device
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instead. Using those variables will make your program more readable and more
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portable. Don't fear ineffective code when using those variables, the
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compiler will translate reads and writes to those structs into direct memory
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accesses.
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<item>Other routines that make sense for only a specific system. One example
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is routines to write memory locations in the system bank for the CBM-II
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family.
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</itemize>
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<sect>Direct console I/O - <tt/conio.h/<p>
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The <tt/conio.h/ header file contains a large set of functions that do screen
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and keyboard I/O. The functions will write directly to the screen or poll the
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keyboard directly with no more help from the operating system than needed.
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This has some disadvantages, but on the other side it's fast and reasonably
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portable. Conio implementations exist for the following targets:
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<itemize>
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<item>apple2
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<item>apple2enh
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<item>atari
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<item>atari5200
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<item>atarixl
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<item>atmos
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<item>c128
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<item>c16 (works also for the c116 with up to 32K memory)
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<item>c64
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<item>cbm510 (40-column video)
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<item>cbm610 (all CBM series-II computers with 80-column video)
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<item>creativision
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<item>cx16
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<item>gamate
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<item>geos-apple
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<item>geos-cbm
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<item>nes
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<item>osic1p
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<item>pce
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<item>pet (all CBM PET systems except the 2001)
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<item>plus4 (or expanded c16/c116)
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<item>telestrat
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<item>vic20
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</itemize>
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The <tt/conio.h/ header file does include the system-specific header files also,
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which define constants for special characters and keys.
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<sect>Using the joystick - <tt/joystick.h/<p>
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For systems that have a joystick, <tt/joystick.h/ will define a subroutine to
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read the current value, including constants to evaluate the result of that
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function.
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<sect>Using a mouse - <tt/mouse.h/<p>
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Some target machines support a mouse. Mouse support currently is available for
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the following targets:
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<itemize>
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<item>apple2
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<item>apple2enh
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<item>atari
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<item>atarixl
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<item>c128
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<item>c64
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<item>cbm510
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<item>cx16
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</itemize>
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The available functions are declared in <tt/mouse.h/.
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<sect>Copyright<p>
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This C runtime library implementation for the cc65 compiler is (C)
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Copyright 1998-2002 Ullrich von Bassewitz. For usage of the binaries
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and/or sources, the following conditions do apply:
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This software is provided 'as-is', without any expressed or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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<enum>
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<item> The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated, but is not required.
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<item> Altered source versions must be marked plainly as such, and must not
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be misrepresented as being the original software.
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<item> This notice may not be removed or altered from any source
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distribution.
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</enum>
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</article>
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