From: cpg Date: Thu, 16 Oct 2003 18:04:46 +0000 (+0000) Subject: first version, most text by Shawn X-Git-Tag: V2.12.0~1256 X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=8bdabba50ff28c4055ebbe90a6323127e54dbbb4;p=cc65 first version, most text by Shawn git-svn-id: svn://svn.cc65.org/cc65/trunk@2536 b7a2c559-68d2-44c3-8de9-860c34a00d81 --- diff --git a/doc/atari.sgml b/doc/atari.sgml new file mode 100644 index 000000000..a564cf86a --- /dev/null +++ b/doc/atari.sgml @@ -0,0 +1,203 @@ + + +
+ +Atari specific information for cc65 +<author>Shawn Jefferson, <htmlurl url="mailto:shawnjefferson@24fightingchickens.com" name="shawnjefferson@24fightingchickens.com"> +Christian Groessler, <htmlurl url="cpg@aladdin.de" name="cpg@aladdin.de"> +<date>16-Oct-2003 + +<abstract> +An overview over the Atari 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 Atari runtime system as it comes +with the cc65 C compiler. It describes the memory layout, Atari specific +header files, available drivers, and any pitfalls specific to that +platform. + +Please note that Atari 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 +Atari target is a machine language program with a standard executable +header (FF FF <start address> <end address>). These values are +calculated in the crt0.s file from the __CODE_LOAD__ and __BSS_LOAD__ +values, so keep this in mind if you create a custom linker config file +and start moving segments around. You can override this behaviour by +creating your own crt0.s file and linking it into your program. A run +vector is added to the end of the file ($02E0 <run vector>) +and is calculated using __CODE_LOAD__ in crt0.s also. + + +<sect>Memory layout<p> + +The default linker script assumes that the BASIC ROM is disabled (or +the BASIC cartridge unplugged). This gives a unsable memory range from +$2E00 - $BC1F. The library startup code examines the +current memory configuration, which depends on the size of the +installed memory and cartridges present, by inspecting the value in +the MEMTOP ($2E5) variable. Then the initial stack pointer, +which indicates the upper bound of memory used, is adjusted. The load +address of $2E00 was chosen to accommodate having a DOS loaded +and a driver that resides in low memory such as the 850 R: handler. +You can override this behaviour by creating a custom linker config +file. + +Special locations: + +<descrip> + <tag/Text screen/ + The text screen depends on the installed memory size and cartridges + and can be obtained from the SAVMSC variable ($58). + + <tag/Stack/ + The C runtime stack is located at MEMTOP and grows downwards, + regardless of how your linker config file is setup. This + accomodates the different memory configurations of the Atari + machines, as well as having a cartridge installed. You can override + this behaviour by writing your own crt0.s file and linking it to + your program. + + <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 Atari specific code may use the <tt/atari.h/ +header file. + + +<sect1>Atari specific functions<p> + +The functions listed below are special for the Atari. See the <htmlurl +url="funcref.html" name="function reference"> for declaration and usage. + +<!-- TODO: the other functions --> +<itemize> +<item>get_ostype +<item>graphics +</itemize> + + +<sect1>Hardware access<p> + +The following pseudo variables declared in the <tt/atari.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/GTIA_READ/ and <tt/GTIA_WRITE/</tag> + The <tt/GTIA_READ/ structure allows read access to the GTIA. The + <tt/GTIA_WRITE/ structure allows write access to the GTIA. + See the <tt/_gtia.h/ header file located in the include directory + for the declaration of the structure. + + <tag><tt/POKEY_READ/ and <tt/POKEY_WRITE/</tag> + The <tt/POKEY_READ/ structure allows read access to the POKEY. The + <tt/POKEY_WRITE/ structure allows write access to the POKEY. + See the <tt/_pokey.h/ header file located in the include directory + for the declaration of the structure. + + <tag><tt/ANTIC/</tag> + The <tt/ANTIC/ structure allows read access to the ANTIC. + See the <tt/_antic.h/ header file located in the include directory + for the declaration of the structure. + +<!-- TODO: the other things from atari.h --> + +</descrip><p> + + + +<sect>Loadable drivers<p> + +<sect1>Graphics drivers<p> + +Currently there are no graphics drivers available for the Atari platform. + +<sect1>Extended memory drivers<p> + +Currently there are no extended memory drivers available for the Atari +platform. + +<sect1>Joystick drivers<p> + +<descrip> + + <tag><tt/atari-stdjoy.joy/</tag> + Supports up to four standard joysticks connected to the joystick ports of + the Atari. + +</descrip><p> + + + +<sect1>Mouse drivers<p> + +Currently no drivers available (in fact, the API for loadable mouse drivers +does not exist). There is a static driver you can use. + + +<sect1>RS232 device drivers<p> + +Currently there are no RS232 loadable drivers available for the Atari +platform. There is a static driver you can use. + + +<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>