--- /dev/null
+<!doctype linuxdoc system>
+
+<article>
+
+<title>c64 specific information for cc65
+<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org">
+<date>2003-09-23
+
+<abstract>
+An overview over the C64 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 C64 runtime system as it comes with the
+cc65 C compiler. It describes the memory layout, C64 specific header files,
+available drivers, and any pitfalls specific to that platform.
+
+Please note that C64 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 C64 target
+is a machine language program with a one line BASIC stub. This means that a
+program can be loaded as BASIC program and started with RUN. It is of course
+possible to change this behaviour by using a modified startup file and linker
+config.
+
+
+<sect>Memory layout<p>
+
+cc65 generated programs with the default setup run with the I/O area and the
+kernal ROM enabled. The BASIC ROM is disabled, which gives a usable memory
+range of $0800 - $CFFF. This means that kernal entry points may
+be called directly, but using the BASIC ROM is not possible without additional
+code.
+
+Special locations:
+
+<descrip>
+ <tag/Text screen/
+ The text screen is located at $400 (as in the standard setup).
+
+ <tag/Stack/
+ The C runtime stack is located at $CFFF and growing downwards.
+</descrip><p>
+
+
+
+<sect>Platform specific header files<p>
+
+Programs containing C64 specific code may use the <tt/c64.h/ or <tt/cbm.h/
+header files. Using the later may be an option when writing code for more than
+one CBM platform, since it includes <tt/c64.h/ and declares several functions
+common to all CBM platforms.
+
+
+<sect1>C64 specific functions<p>
+
+The functions listed below are special for the C64. See the <htmlurl
+url="funcref.html" name="function reference"> for declaration and usage.
+
+<itemize>
+<item>get_ostype
+</itemize>
+
+
+<sect1>CBM specific functions<p>
+
+Some functions are available for all (or at least most) of the Commodore
+machines. See the <htmlurl url="funcref.html" name="function reference"> for
+declaration and usage.
+
+<itemize>
+<item>cbm_close
+<item>cbm_closedir
+<item>cbm_k_setlfs
+<item>cbm_k_setnam
+<item>cbm_k_load
+<item>cbm_k_save
+<item>cbm_k_open
+<item>cbm_k_close
+<item>cbm_k_readst
+<item>cbm_k_chkin
+<item>cbm_k_ckout
+<item>cbm_k_basin
+<item>cbm_k_bsout
+<item>cbm_k_clrch
+<item>cbm_load
+<item>cbm_open
+<item>cbm_opendir
+<item>cbm_read
+<item>cbm_readdir
+<item>cbm_save
+<item>cbm_write
+<item>get_tv
+</itemize>
+
+
+<sect1>Hardware access<p>
+
+The following pseudo variables declared in the <tt/c64.h/ header file do allow
+access to hardware located in the address space. Some variables are
+structures, accessing the struct fields will access the chip registers.
+
+<descrip>
+
+ <tag><tt/VIC/</tag>
+ The <tt/VIC/ structure allows access to the VIC II (the graphics
+ controller). See the <tt/_vic2.h/ header file located in the include
+ directory for the declaration of the structure.
+
+ <tag><tt/SID/</tag>
+ The <tt/SID/ structure allows access to the SID (the sound interface
+ device). See the <tt/_sid.h/ header file located in the include directory
+ for the declaration of the structure.
+
+ <tag><tt/CIA1, CIA2/</tag>
+ Access to the two CIA (complex interface adapater) chips is available via
+ the <tt/CIA1/ and <tt/CIA2/ variables. The structure behind these variables
+ is explained in <tt/_cia.h/.
+
+ <tag><tt/COLOR_RAM/</tag>
+ A character array that mirrors the color RAM of the C64 at $D800.
+
+</descrip><p>
+
+
+
+<sect>Loadable drivers<p>
+
+<sect1>Graphics drivers<p>
+
+All available graphics drivers for the TGI interface will use the space below
+the I/O area and kernal ROM, so you can have hires graphics in the standard
+setup without any memory loss or need for a changed configuration.
+
+<descrip>
+ <tag><tt/c64-hi.tgi/</tag>
+ This driver features a resolution of 320*200 with two colors and an
+ adjustable palette (that means that the two colors can be choosen out of a
+ palette of the 16 C64 colors).
+</descrip><p>
+
+
+<sect1>Extended memory drivers<p>
+
+<descrip>
+
+ <tag><tt/c64-georam.emd/</tag>
+ A driver for the GeoRam cartridge. The driver will always assume 2048 pages
+ of 256 bytes each.
+
+ <tag><tt/c64-ram.emd/</tag>
+ A driver for the hidden RAM below the I/O area and kernal ROM. Supports 48
+ 256 byte pages. Please note that this driver is incompatible with any of the
+ graphics drivers!
+
+ <tag><tt/c64-ramcart.emd/</tag>
+ A driver for the RamCart 64/128. Will test the hardware for the available
+ RAM.
+
+ <tag><tt/c64-reu.emd/</tag>
+ A driver for the CBM REUs. The driver will determine from the connected REU
+ if it supports 128KB of RAM or more. In the latter case, 256KB are assumed,
+ but since there are no range checks, the application can use more memory if
+ it has better knowledge about the hardware than the driver.
+
+ <tag><tt/c64-vdc.emd/</tag>
+ A driver for the VDC memory of the C128. Can be used if the program is
+ running in C64 mode of the C128. Autodetects the amount of memory available
+ (16 or 64K) and offers 64 or 256 pages of 256 bytes each.
+
+</descrip><p>
+
+
+<sect1>Joystick drivers<p>
+
+<descrip>
+
+ <tag><tt/c64-stdjoy.joy/</tag>
+ Supports up to two standard joysticks connected to the joysticks port of
+ the C64.
+
+</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>
+
+<descrip>
+
+ <tag><tt/c64-swlink.ser/</tag>
+ Driver for the SwiftLink cartridge. Supports up to 38400 baud, hardware flow
+ control (RTS/CTS) and interrupt driven receives.
+
+</descrip><p>
+
+
+
+<sect>Other hints<p>
+
+
+
+
+<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>
+
+
+
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