diff --git a/doc/Makefile b/doc/Makefile index 9f26c13dc..5dba9d86b 100644 --- a/doc/Makefile +++ b/doc/Makefile @@ -26,6 +26,7 @@ SGML = apple2.sgml \ c64.sgml \ ca65.sgml \ ca65html.sgml \ + cbm510.sgml \ cbm610.sgml \ cc65.sgml \ cl65.sgml \ @@ -111,13 +112,13 @@ zap: clean # ------------------------------------------------------------------------------ # Special target rules - + coding.html: coding.sgml sgml2html --split=0 $< # funcref.sgml's third section is huge. # So, funcref.html is split into sub-section files. -# +# funcref.html: funcref.sgml sgml2html --split=2 $(BUTTONS) $< diff --git a/doc/cbm510.sgml b/doc/cbm510.sgml new file mode 100644 index 000000000..97d37a1df --- /dev/null +++ b/doc/cbm510.sgml @@ -0,0 +1,298 @@ + + +
+ +Commodore 510 (aka P500) specific information for cc65 +<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org"> +Stefan A. Haubenthal, <htmlurl url="mailto:polluks@sdf.lonestar.org" name="polluks@sdf.lonestar.org"> +<date>2006-05-22 + +<abstract> +An overview over the Commodore 510 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 CBM 510 runtime system as it comes with +the cc65 C compiler. It describes the memory layout, CBM 510 specific header +files, available drivers, and any pitfalls specific to that platform. + +Please note that CBM 510 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. + +In addition to the Commodore 510 (named P128 in the U.S.), no other +machines are supported by this cc65 target. + + + +<sect>Binary format<p> + +The standard binary output format generated by the linker for the CBM510 +target is a machine language program with a short 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 for the Commodore 510 run in bank 0, the memory bank +reserved for BASIC programs. Since there are no ROMs in this memory bank, the +program has almost full 64K for its own. A disadvantage is that kernal +subroutines cannot be called (at least not in a fast and effective manner), so +the runtime has replace kernal functionality. + +The default memory configuration for the CBM 510 allocates all memory between +$0002 and $FFF0 in bank 0 for the compiled program. Some space +in low memory is lost, because a separate hardware stack is set up in page 1, +and the kernal replacement functions need some more memory locations. A few +more pages are lost in high memory, because the runtime sets up a copy of the +character ROM, a text screen and a CBM compatible jump table at $FF81. +The main startup code is located at $0400, so about 54K of the complete +bank are actually usable for applications. + +Special locations: + +<descrip> + <tag/Stack/ + The C runtime stack is located at $FF81 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 CBM 510 specific code may use the <tt/cbm510.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/cbm510.h/ and declares +several functions common to all CBM platforms. + +<sect1>CBM 510 specific functions<p> + +The functions listed below are special for the CBM 510. See the <htmlurl +url="funcref.html" name="function reference"> for declaration and usage. + +<itemize> +<item>peekbsys +<item>peekwsys +<item>pokebsys +<item>pokewsys +</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/cbm510.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. + +<bf>Note:</bf> All I/O chips are located in the system bank (bank 15) and can +therefore not be accessed like on other platforms. Please use one of the +<tt/peekbsys/, <tt/peekwsys/, <tt/pokebsys/ and <tt/pokewsys/ functions to +access the I/O chips. Direct reads and writes to the structures named below +will <em>not</em> work! + +<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/ACIA/</tag> + Access to the ACIA (the RS232 chip) is available via the <tt/ACIA/ variable. + See the <tt/_6551.h/ header file located in the include directory for the + declaration of the structure. + + <tag><tt/CIA/</tag> + Access to the CIA chip is available via the <tt/CIA/ variable. See the + <tt/_6526.h/ header file located in the include directory for the + declaration of the structure. + + <tag><tt/TPI1, TPI2/</tag> + The two 6525 triport chips may be accessed by using this variable. See the + <tt/_6525.h/ header file located in the include directory for the + declaration of the structure. + +</descrip><p> + + + +<sect>Loadable drivers<p> + + +<sect1>Graphics drivers<p> + +No graphics drivers are currently available for the Commodore 510. + + +<sect1>Extended memory drivers<p> + +<descrip> + <tag><tt/cbm510-ram.emd/</tag> + A driver for the RAM in bank 1. Supports up to 255 pages with 256 bytes + each. +</descrip><p> + + +<sect1>Joystick drivers<p> + +<descrip> + + <tag><tt/cbm510-std.joy/</tag> + Supports up to two standard joysticks connected to the joysticks port of + the Commodore 510. + +</descrip><p> + + +<sect1>Mouse drivers<p> + +No mouse drivers are currently available for the Commodore 510. + + +<sect1>RS232 device drivers<p> + +<descrip> + + <tag><tt/cbm510-std.ser/</tag> + Driver for the 6551 ACIA chip built into the Commodore 510. Supports up to + 19200 baud, hardware flow control (RTS/CTS) and interrupt driven receives. + Note that because of the peculiarities of the 6551 chip transmits are not + interrupt driven, and the transceiver blocks if the receiver asserts flow + control because of a full buffer. + +</descrip><p> + + +<sect>Limitations<label id="limitations"><p> + + +<sect1>Kernal and hardware access<p> + +Since the program runs in bank 0, and the kernal and all I/O chips are located +in bank 15, calling ROM routines or accessing hardware needs special code. The +cc65 runtime implements wrappers for all functions in the kernal jump table. +While this simplifies things, it should be noted that the wrappers do have +quite an impact on performance: A cross bank call has an extra 300µs +penalty added by the wrapper. + +<sect1>Interrupts<p> + +Compiled programs contain an interrupt handler that runs in the program bank. +This has several advantages, one of them being performance (see cross bank +call overhead mentioned above). However, this introduces one problem: +Interrupts are lost while the CPU executes code in the kernal bank. As a +result, the clock may go wrong and (worse) serial interrupts may get lost. + +Since the cc65 runtime does only call the kernal for disk I/O, this means that +a program should not do file I/O while it depends on interrupts. + + +<sect>Other hints<p> + +<sect1>Passing arguments to the program<p> + +Command line argument passing is currently not supported for the Commodore +510. + + +<sect1>Program return code<p> + +The program return code (signed char) is passed back to BASIC by use of the +<tt/ST/ variable. + + +<sect1>Interrupts<p> + +The runtime for the Commodore 510 uses routines marked as <tt/.CONDES/ type 2 +for interrupt handlers. Such routines must be written as simple machine +language subroutines and will be called automatically by the interrupt handler +code when they are linked into a program. See the discussion of the +<tt/.CONDES/ feature in the <htmlurl url="ca65.html" name="assembler manual">. + + + +<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> diff --git a/doc/index.sgml b/doc/index.sgml index f6ef30bee..dbfed2f56 100644 --- a/doc/index.sgml +++ b/doc/index.sgml @@ -120,6 +120,9 @@ Main documentation page, contains links to other available stuff. <tag><htmlurl url="c64.html" name="c64.html"></tag> Topics specific to the Commodore 64. + <tag><htmlurl url="cbm510.html" name="cbm510.html"></tag> + Topics specific to the Commodore 510. + <tag><htmlurl url="cbm610.html" name="cbm610.html"></tag> Topics specific to the Commodore 610.