mirror of
https://github.com/cc65/cc65.git
synced 2024-11-18 15:05:14 +00:00
247 lines
6.9 KiB
Plaintext
247 lines
6.9 KiB
Plaintext
<!doctype linuxdoc system>
|
|
|
|
<article>
|
|
<title>PC-Engine (TurboGrafx 16) System-specific information for cc65
|
|
<author><url url="mailto:groepaz@gmx.net" name="Groepaz">,<newline>
|
|
<url url="mailto:greg.king5@verizon.net" name="Greg King">
|
|
|
|
<abstract>
|
|
An overview over the PCE 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 PCE runtime system as it comes
|
|
with the cc65 C compiler. It describes the memory layout, PCE-specific header
|
|
files, available drivers, and any pitfalls specific to that platform.
|
|
|
|
Please note that PCE-specific functions are just mentioned here; they are
|
|
described, in detail, in the separate <url url="funcref.html" name="function
|
|
reference">. Even functions marked as "platform dependent" might be available on
|
|
more than one platform. Please see the function reference for more
|
|
information.
|
|
|
|
|
|
|
|
<sect>Binary format<p>
|
|
|
|
The binary output file generated by the linker, for the PCE target, is an
|
|
image, with no header, that has 8K bytes in the wrong place. That file must be
|
|
post-processed; the 8K at the end must be moved to the front of the image.
|
|
|
|
On POSIX systems, the <tt/dd/ command and the shell give a convenient way to do
|
|
it. Here is an example of their use:
|
|
<tscreen><verb>
|
|
dd if=conio.bin bs=8K skip=3 > conio.pce
|
|
dd if=conio.bin bs=8K count=3 >> conio.pce
|
|
</verb></tscreen>
|
|
The first command grabs the last 8K of a 32K file, and writes it as the first
|
|
part of a new file. The second command reads all but the last part of the old
|
|
file, and appends it to the new file.
|
|
<tscreen><verb>
|
|
+--------+--------+--------+--------+
|
|
| Bank 1 | Bank 2 | Bank 3 | Bank 0 | <-- "conio.bin"
|
|
+--------+--------+--------+--------+
|
|
|
|
+--------+--------+--------+--------+
|
|
| Bank 0 | Bank 1 | Bank 2 | Bank 3 | <-- "conio.pce"
|
|
+--------+--------+--------+--------+
|
|
</verb></tscreen>
|
|
<em/Note/: That <tt/.pce/ file shows the format of the ROM cartridge that is
|
|
plugged into a PC-Engine. But, that <tt/.bin/ file shows what programs
|
|
actually see when they execute the code in that cartridge.
|
|
|
|
|
|
|
|
<sect>Memory layout<p>
|
|
|
|
cc65-generated programs with the default setup run with the memory map that was
|
|
used by many PC-Engine games:
|
|
<itemize>
|
|
<item>The first 8K bytes is the I/O area.
|
|
<item>The second 8K bytes is RAM, which holds
|
|
<itemize>
|
|
<item>the redirected zero-page and the redirected hardware stack page,
|
|
<item>and 7680 bytes of general memory ($2200 - $3FFF).
|
|
</itemize>
|
|
<item>The last 8K bytes in the usual 64K-byte range is the ROM that holds the
|
|
program.
|
|
</itemize>
|
|
|
|
Special locations:
|
|
|
|
<descrip>
|
|
<tag/Text screen and Font/
|
|
The text screen is located at Video RAM (VRAM) address $0000;
|
|
the Font is located at VRAM address $2000.
|
|
|
|
<tag/Stack/
|
|
The C run-time stack is located in system RAM at $3FFF;
|
|
and, grows downwards.
|
|
|
|
<tag/Data and BSS/
|
|
The Data (initialized variables) and BSS (uninitialized variables) sections are
|
|
placed one after the other into system RAM at $2200.
|
|
|
|
<tag/Heap/
|
|
The C heap is located after the end of the BSS section;
|
|
and, extends up to the C run-time stack.
|
|
|
|
<tag/Code/
|
|
In an 8K ROM cartridge, code and read-only data are located between
|
|
$E000 and $FFF5 in the System bank.
|
|
|
|
In a 16K cartridge, code and read-only data are located between $C000
|
|
and $FFF5.
|
|
|
|
In a 32K cartridge, code and read-only data are located between $8000
|
|
and $FFF5.
|
|
</descrip>
|
|
|
|
|
|
|
|
<sect>Platform-specific header files<p>
|
|
|
|
Programs containing PCE-specific code may use the <tt/pce.h/ header file.
|
|
|
|
|
|
<sect1>PCE-specific functions<p>
|
|
|
|
<itemize>
|
|
<item>get_tv (since all PCE systems are NTSC, this always returns TV_NTSC)</item>
|
|
<item>waitvsync</item>
|
|
</itemize>
|
|
|
|
|
|
<sect1>Hardware access<p>
|
|
|
|
The following constants, defined in the <tt/pce.inc/ include file, do
|
|
allow access to hardware that is located in the address space.
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/PSG/</tag>
|
|
The <tt/PSG/ defines allow access to the PSG (Programmable Sound Generator).
|
|
|
|
<tag><tt/VCE/</tag>
|
|
The <tt/VCE/ defines allow access to the VCE chip (Video Color Encoder).
|
|
|
|
<tag><tt/VDC/</tag>
|
|
The <tt/VDC/ defines allow access to the VDC chip (Video Display Controller).<newline>
|
|
32K of 16-bit words of Video RAM can be accessed only through this chip.
|
|
|
|
</descrip>
|
|
|
|
|
|
|
|
<sect>Loadable drivers<p>
|
|
|
|
All drivers must be statically linked because no file I/O is available.
|
|
The names in the parentheses denote the symbols to be used for static linking of the drivers.
|
|
|
|
|
|
<sect1>Graphics drivers<p>
|
|
|
|
No TGI graphics drivers are currently available for the PCE.
|
|
|
|
|
|
<sect1>Extended memory drivers<p>
|
|
|
|
No extended memory drivers are currently available for the PCE.
|
|
|
|
|
|
<sect1>Joystick drivers<p>
|
|
|
|
<descrip>
|
|
|
|
<tag><tt/pce-stdjoy.joy (pce_stdjoy)/</tag>
|
|
A joystick driver for the standard two-button joypad is available.
|
|
|
|
Note that the Japanese 6-button pad currently is not supported.
|
|
|
|
</descrip>
|
|
|
|
|
|
<sect1>Mouse drivers<p>
|
|
|
|
No mouse drivers are currently available for the PCE.
|
|
|
|
|
|
<sect1>RS232 device drivers<p>
|
|
|
|
No serial drivers are currently available for the PCE.
|
|
|
|
|
|
|
|
<sect>Limitations<p>
|
|
|
|
|
|
<sect1>Disk I/O<p>
|
|
|
|
The existing library for the PCE doesn't implement C file
|
|
I/O. There are no hacks for the <tt/read()/ and <tt/write()/ routines.
|
|
|
|
To be more concrete, that limitation means that you cannot use any of the
|
|
following functions (and a few others):
|
|
|
|
<itemize>
|
|
<item>printf
|
|
<item>fclose
|
|
<item>fopen
|
|
<item>fread
|
|
<item>fprintf
|
|
<item>fputc
|
|
<item>fscanf
|
|
<item>fwrite
|
|
<item>...
|
|
</itemize>
|
|
|
|
|
|
|
|
<sect>Other hints<p>
|
|
|
|
Some useful resources on PCE coding:
|
|
|
|
<itemize>
|
|
<item><url url="http://blog.blockos.org/?tag=pc-engine">
|
|
<item><url url="http://pcedev.blockos.org/viewforum.php?f=5">
|
|
<item><url url="http://www.romhacking.net/?page=documents&platform=4">
|
|
<item><url url="http://archaicpixels.com/Main_Page">
|
|
|
|
<item><url url="http://www.magicengine.com/mkit/doc.html">
|
|
|
|
<item><url url="https://github.com/uli/huc">
|
|
<item><url url="http://www.zeograd.com/parse.php?src=hucf">
|
|
</itemize>
|
|
|
|
|
|
|
|
<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 marked plainly 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>
|