mirror of
https://github.com/cc65/cc65.git
synced 2024-12-30 20:29:25 +00:00
263 lines
7.0 KiB
Plaintext
263 lines
7.0 KiB
Plaintext
<!doctype linuxdoc system>
|
|
|
|
<article>
|
|
|
|
<title>Apple ][ specific information for cc65
|
|
<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
|
|
<date>2003-12-16
|
|
|
|
<abstract>
|
|
An overview over the Apple ][ runtime system as it is
|
|
implemented for the cc65 C compiler.
|
|
</abstract>
|
|
|
|
<!-- Table of contents -->
|
|
<toc>
|
|
|
|
<!-- Begin the document -->
|
|
|
|
<sect>Overview<p>
|
|
|
|
This file contains an overview of the Apple ][ runtime system
|
|
as it comes with the cc65 C compiler. It describes the memory layout,
|
|
Apple ][ specific header files, available drivers, and any
|
|
pitfalls specific to that platform.
|
|
|
|
Please note that Apple ][ specific functions are just mentioned
|
|
here, they are described in detail in the separate <htmlurl url="funcref.html"
|
|
name="function reference">. Even functions marked as "platform dependent" may
|
|
be available on more than one platform. Please see the function reference for
|
|
more information.
|
|
|
|
|
|
<sect>Binary format<p>
|
|
|
|
The standard binary output format generated by the linker for the
|
|
Apple ][ target is a machine language program with a 4 byte DOS
|
|
3.3 header. The standard load address is $800.
|
|
|
|
The DOS header is in its own segment named <tt/EXEHDR/. If you don't want the
|
|
header for some reason, you can change
|
|
|
|
<verb>
|
|
HEADER: start = $0000, size = $4, file = %O;
|
|
</verb>
|
|
|
|
to
|
|
|
|
<verb>
|
|
HEADER: start = $0000, size = $4, file = "";
|
|
</verb>
|
|
|
|
in the linker configuration to have the linker remove it.
|
|
|
|
|
|
|
|
<sect>Memory layout<p>
|
|
|
|
In the standard setup, cc65 generated programs use the memory from
|
|
$800 to $8E00, so 33.5K of memory (including the stack) is
|
|
available. ROM calls are possible without further precautions.
|
|
|
|
Special locations:
|
|
|
|
<descrip>
|
|
<tag/Stack/
|
|
The C runtime stack is located at $8DFF and growing downwards.
|
|
|
|
<tag/Heap/
|
|
The C heap is located at the end of the program and grows towards the C
|
|
runtime stack.
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect>Platform specific header files<p>
|
|
|
|
Programs containing Apple ][ specific code may use the
|
|
<tt/apple2.h/ header file.
|
|
|
|
|
|
<sect1>Apple ][ specific functions<p>
|
|
|
|
The functions listed below are special for the Apple ][. See
|
|
the <htmlurl url="funcref.html" name="function reference"> for declaration and
|
|
usage.
|
|
|
|
<itemize>
|
|
<item>get_ostype
|
|
</itemize>
|
|
|
|
|
|
|
|
<sect1>Hardware access<p>
|
|
|
|
There's currently no support for direct hardware access. This does not mean
|
|
you cannot do it, it just means that there's no help.
|
|
|
|
|
|
|
|
<sect>Loadable drivers<p>
|
|
|
|
<em>Note:</em> Since the Apple ][ doesn't have working disk I/O
|
|
(see <ref id="limitations" name="section "Limitations"">), the
|
|
available drivers cannot be loaded at runtime (so the term "loadable drivers"
|
|
is somewhat misleading). Instead, the drivers have to be converted using the
|
|
<htmlurl url="co65.html" name="co65 utility"> and statically linked. While
|
|
this may seem overhead, it has two advantages:
|
|
|
|
<enum>
|
|
<item>The interface is identical to the one used for other platforms
|
|
and to the one for the Apple ][ once it has disk I/O.
|
|
<item>Once disk I/O is available, existing code can be changed to load drivers
|
|
at runtime with almost no effort.
|
|
</enum>
|
|
|
|
|
|
|
|
<sect1>Graphics drivers<p>
|
|
|
|
<em>Note:</em> Since memory for the high resolution graphics has to be allocated,
|
|
programs using graphics drivers will have to be linked using a special linker
|
|
configuration. See the <tt/apple2-tgi.cfg/ file in the documentation
|
|
directory, and the <htmlurl url="ld65.html" name="linker documentation"> on
|
|
how to use it.
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/a2.lo.tgi/</tag>
|
|
This driver was written by Stefan Haubenthal. It features a resolution of
|
|
40×40 with 16 colors. At the bottom of the screen, 4 additional text lines
|
|
are available.
|
|
|
|
<tag><tt/a2.hi.tgi/</tag>
|
|
This driver was written by Stefan Haubenthal. It features a resolution of
|
|
280×192 with 6 colors.
|
|
|
|
</descrip><p>
|
|
|
|
|
|
<sect1>Extended memory drivers<p>
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/a2.lc.emd/</tag>
|
|
Gives access to 12KB RAM (48 pages of 256 bytes each) on the
|
|
Apple ][ language card. The driver was contributed by
|
|
Stefan Haubenthal. Note: This driver is incompatible with any DOS using
|
|
the language card memory!
|
|
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect1>Joystick drivers<p>
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/a2.stdjoy.joy/</tag>
|
|
Supports up to two standard analog joysticks connected to the game port of
|
|
the Apple ][.
|
|
|
|
</descrip><p>
|
|
|
|
|
|
|
|
<sect1>Mouse drivers<p>
|
|
|
|
Currently no drivers available (in fact, the API for loadable mouse drivers
|
|
does not exist).
|
|
|
|
|
|
<sect1>RS232 device drivers<p>
|
|
|
|
No serial drivers are currently available for the Apple ][.
|
|
|
|
|
|
|
|
<sect>Limitations<label id="limitations"><p>
|
|
|
|
<sect1>Disk I/O<p>
|
|
|
|
The existing library for the Apple ][ doesn't implement C file
|
|
I/O. There are two hacks for the <tt/read()/ and <tt/write()/ routines in
|
|
place, which will make functions work that read from or write to <tt/stdout/
|
|
(like <tt/printf()/). However, these functions have some shortcomings which
|
|
won't be fixed, because they're going to be replaced anyway.
|
|
|
|
To be more concrete, this limitation means that you cannot use any of the
|
|
following functions (and a few others):
|
|
|
|
<itemize>
|
|
<item>fclose
|
|
<item>fopen
|
|
<item>fread
|
|
<item>fprintf
|
|
<item>fputc
|
|
<item>fscanf
|
|
<item>fwrite
|
|
<item>...
|
|
</itemize>
|
|
|
|
|
|
<sect>Other hints<p>
|
|
|
|
<sect1>Passing arguments to the program<p>
|
|
|
|
Command line arguments can be passed to <tt/main()/. Since this is not
|
|
supported by BASIC, the following syntax was choosen:
|
|
|
|
<tscreen><verb>
|
|
CALL2048:REM,ARG1," ARG2", ARG 3,, ARG5, ...
|
|
</verb></tscreen>
|
|
|
|
<enum>
|
|
<item>Arguments are separated by commas.
|
|
<item>There must be a comma after the first <tt/REM/.
|
|
<item>Leading spaces are ignored; trailing spaces are included unless the
|
|
argument was quoted.
|
|
<item>The first argument passed to <tt/main/ is the program name.
|
|
</enum>
|
|
|
|
|
|
<sect1>Function keys<p>
|
|
|
|
These are defined to be OpenApple + number key.
|
|
|
|
|
|
|
|
<sect>Bugs/Feedback<p>
|
|
|
|
If you have problems using the library, 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>License<p>
|
|
|
|
This software is provided 'as-is', without any expressed or implied
|
|
warranty. In no event will the authors be held liable for any damages
|
|
arising from the use of this software.
|
|
|
|
Permission is granted to anyone to use this software for any purpose,
|
|
including commercial applications, and to alter it and redistribute it
|
|
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.
|
|
</enum>
|
|
|
|
</article>
|
|
|
|
|
|
|