From: ol.sc Date: Fri, 9 Oct 2009 22:19:35 +0000 (+0000) Subject: Added quite some info on the stuff in 'cfg' and 'obj'. Apple2enh needs to be adjusted... X-Git-Tag: V2.13.1~170 X-Git-Url: https://git.sur5r.net/?a=commitdiff_plain;h=b7071c05a28ebf4b10fd854a48631404e772cfec;p=cc65 Added quite some info on the stuff in 'cfg' and 'obj'. Apple2enh needs to be adjusted too for sure, but check the result of the nightly build first. git-svn-id: svn://svn.cc65.org/cc65/trunk@4352 b7a2c559-68d2-44c3-8de9-860c34a00d81 --- diff --git a/doc/apple2.sgml b/doc/apple2.sgml index 1abcf3eda..f70a6277a 100644 --- a/doc/apple2.sgml +++ b/doc/apple2.sgml @@ -3,8 +3,8 @@
Apple ][ specific information for cc65 -<author>Ullrich von Bassewitz, <htmlurl url="mailto:uz@cc65.org" name="uz@cc65.org"> -<date>2003-12-16 +<author>Oliver Schmidt, <htmlurl url="mailto:ol.sc@web.de" name="ol.sc@web.de"> +<date>2009-10-07 <abstract> An overview over the Apple ][ runtime system as it is @@ -33,48 +33,31 @@ 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 containing the load address and load size. The standard load address -is $803. - -The DOS 3.3 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 = $0004, file = %O; -</verb> - -to - -<verb> - HEADER: start = $0000, size = $0004, file = ""; -</verb> - -in the linker configuration to have the linker remove it. +The standard binary file format generated by the linker for the +Apple ][ target is a binary program with a 4 byte DOS 3.3 header +containing the load address and load length. The default load address is +$803. <bf/AppleCommander 1.3.5/ or later (available at <url -url="http://applecommander.sourceforge.net/">) includes an option <tt/-cc65/ -that allows to put binary files with the DOS 3.3 header onto disk images -containing either DOS 3.3 or ProDOS 8. - -Please note that there is an <bf/Apple ][ ProDOS 8 system program -for loading binary programs/ available in the cc65 User Contributions section. -It adds all benefits of a ProDOS 8 system program to the standard binary -program generated by the linker for the Apple ][ target. +url="http://applecommander.sourceforge.net/">) includes the option <tt/-cc65/ +that allows to put binary files with a DOS 3.3 header onto disk images +containing DOS 3.3 as well as ProDOS 8. +For ProDOS 8 system programs the load address is fixed to $2000 so there +is no need for a header. Therefore the linker configuration +<htmlurl url="apple2-4.html#ss4.3" name="apple2-system.cfg"> for those programs +omits the DOS 3.3 header. <sect>Memory layout<p> In the standard setup, cc65 generated programs use the memory from -$803 to $95FF, so 35.5KB of RAM are available. While running -<tt/main()/ the Language Card bank 2 is enabled for read access. However while -running module constructors/destructors the Language Card is disabled. +$803 to $95FF, so 35.5 KB of RAM are available. Special locations: <descrip> + <tag/Stack/ The C runtime stack is located at HIMEM and grows downwards, regardless of how your linker config file is setup. @@ -82,33 +65,215 @@ Special locations: <tag/Heap/ The C heap is located at the end of the program and grows towards the C runtime stack. + </descrip><p> -Enabling the Language Card allows to use it as additional memory for executable -code. Actually doing so requires either to compile code with the option -<tt/--code-name HIGHCODE/ or to use <tt/#pragma codeseg ("HIGHCODE")/. +While running <tt/main()/ the Language Card bank 2 is enabled for read access. +However while running module constructors/destructors the Language Card is disabled. -The amount of memory available in the Language Card for executable code depends -on the chosen program environment. A plain vanilla ProDOS 8 doesn't actually -use the Language Card bank 2 memory from $D400 to $DFFF. -Therefore the builtin linker configuration defines these 3KB as <tt/LC/ memory -area for executable code. +Enabling the Language Card allows to use it as additional memory for cc65 +generated code. However code is never automatically placed there. Rather code +needs to be explicitly placed in the Language Card either per file by compiling +with <tt/--code-name HIGHCODE/ or per function by enclosing in <tt/#pragma +codeseg (push, "HIGHCODE")/ and <tt/#pragma codeseg (pop)/. In either case the +cc65 runtime system takes care of actually moving the code into the Language +Card. -A plain vanilla DOS 3.3 doesn't make use of the Language Card at all. So you -can change +The amount of memory available in the Language Card for generated code depends +on the chosen <htmlurl url="apple2-4.html" name="linker configuration">. -<verb> - LC: start = $D400, size = $0C00, define = yes; -</verb> -to -<verb> - LC: start = $D000, size = $3000, define = yes; -</verb> +<sect>Linker configurations<p> + +The ld65 linker comes with a builtin config file for the Apple ][, +which is used via <tt/-t apple2/ (and displayed via <tt/--dump-config apple2/). +The apple2 package comes with additional secondary linker config files, which +are used via <tt/-C <configfile>/. + + +<sect1>builtin config file<p> + +Default configuration optimized for a binary program running on ProDOS 8 with +BASIC.SYSTEM. A plain vanilla ProDOS 8 doesn't actually use the Language Card +bank 2 memory from $D400 to $DFFF. + +<descrip> + + <tag><tt/RAM:/ Main memory area</tag> + From $803 to $95FF (35.5 KB) + + <tag><tt/LC:/ Language Card memory area</tag> + From $D400 to $DFFF (3 KB) + + <tag><tt/STARTADDRESS:/ Program start address</tag> + Variable (default: $803) + + <tag><tt/HEADER:/ Binary file header</tag> + DOS 3.3 header (address and length) + +</descrip><p> + + +<sect1><tt/apple2-dos33.cfg/<p> + +Configuration optimized for a binary program running on DOS 3.3. A plain +vanilla DOS 3.3 doesn't make use of the Language Card at all. + +<descrip> + + <tag><tt/RAM:/ Main memory area</tag> + From $803 to $95FF (35.5 KB) + + <tag><tt/LC:/ Language Card memory area</tag> + From $D000 to $FFFF (12 KB) + + <tag><tt/STARTADDRESS:/ Program start address</tag> + Variable (default: $803) + + <tag><tt/HEADER:/ Binary file header</tag> + DOS 3.3 header (address and length) + +</descrip><p> + + +<sect1><tt/apple2-system.cfg/<p> + +Configuration for a system program running on ProDOS 8. + +<descrip> + + <tag><tt/RAM:/ Main memory area</tag> + From $2000 to $BEFF (39.75 KB) + + <tag><tt/LC:/ Language Card memory area</tag> + From $D400 to $DFFF (3 KB) + + <tag><tt/STARTADDRESS:/ Program start address</tag> + Fixed ($2000) -in the linker configuration to define the whole 12KB Language Card address -space as memory area for executable code. + <tag><tt/HEADER:/ Binary file header</tag> + None + +</descrip><p> + + +<sect1><tt/apple2-loader.cfg/<p> + +Configuration optimized for a binary program running on ProDOS 8 without +BASIC.SYSTEM. Intended to be used with <bf/LOADER.SYSTEM - an +Apple ][ ProDOS 8 loader for cc65 programs/, which is available +in the cc65 User Contributions section. + +A program loaded by LOADER.SYSTEM works like a ProDOS 8 system program but +isn't tied to the start adress $2000. Thus with the default start +address $800 the main memory area is increased by 6 KB. + +<descrip> + + <tag><tt/RAM:/ Main memory area</tag> + From $800 to $BEFF (45.75 KB) + + <tag><tt/LC:/ Language Card memory area</tag> + From $D400 to $DFFF (3 KB) + + <tag><tt/STARTADDRESS:/ Program start address</tag> + Variable (default: $800) + + <tag><tt/HEADER:/ Binary file header</tag> + DOS 3.3 header (address and length) + +</descrip><p> + + +<sect1><tt/apple2-reboot.cfg/<p> + +Configuration optimized for a binary program running on ProDOS 8 without +BASIC.SYSTEM. Intended to be used with <bf/LOADER.SYSTEM - an +Apple ][ ProDOS 8 loader for cc65 programs/ (see above) together +with the function <tt/rebootafterexit()/. + +If a ProDOS 8 system program doesn't quit to the ProDOS 8 dispatcher but rather +reboots the machine after exit then a plain vanilla ProDOS 8 doesn't make use of +the Language Card bank 2 at all. + +This setup makes nearly 50 KB available to a cc65 program - on a 64 KB machine! + +<descrip> + + <tag><tt/RAM:/ Main memory area</tag> + From $800 to $BEFF (45.75 KB) + + <tag><tt/LC:/ Language Card memory area</tag> + From $D000 to $DFFF (4 KB) + + <tag><tt/STARTADDRESS:/ Program start address</tag> + Variable (default: $800) + + <tag><tt/HEADER:/ Binary file header</tag> + DOS 3.3 header (address and length) + +</descrip><p> + + + +<sect>ProDOS 8 system programs<p> + +ProDOS 8 system programs are always loaded to the start adress $2000. +For cc65 programs this means that the 6 KB from $800 to $2000 are +by default unused. There are however several options to make use of that memory +range. + + +<sect1>LOADER.SYSTEM<p> + +The easiest (and for really large programs in fact the only) way to have a cc65 +program use the memory from $800 to $2000 is to link it as binary +(as opposed to system) program using the linker configuration +<htmlurl url="apple2-4.html#ss4.4" name="apple2-loader.cfg"> with start address +$800 and load it with <bf/LOADER.SYSTEM - an Apple ][ +ProDOS 8 loader for cc65 programs/. The program then works like a system program +(i.e. quits to the ProDOS dispatcher). + +Using LOADER.SYSTEM is as simple as copying it to the ProDOS 8 directory of the +program to load under name <program>.SYSTEM as a system program. For +example the program <tt/MYPROG/ is loaded by <tt/MYPROG.SYSTEM/. + + +<sect1>Heap<p> + +If the cc65 program can be successully linked as system program using the linker +configuration <htmlurl url="apple2-4.html#ss4.3" name="apple2-system.cfg"> but +uses the heap either explicitly or implicitly (i.e. by loading a driver) then +the memory from $800 to $2000 can be added to the heap by calling +<tt/_heapadd ((void *) 0x0800, 0x1800);/ at the beginning of <tt/main()/. + + +<sect1>ProDOS 8 I/O buffers<p> + +ProDOS 8 requires for every open file a page-aligned 1 KB I/O buffer. By default +these buffers are allocated by the cc65 runtime system on the heap using +<tt/posix_memalign()/. While in general this is the best solution it means quite +some overhead for (especially rather small) cc65 programs which do open files +but do not make use of the heap otherwise. + +The apple2 package comes with the alternative ProDOS 8 I/O buffer allocation +module <tt/apple2-iobuf-0800.o/ which uses the memory between $800 and +the program start address for the 1 KB I/O buffers. For system programs (with +start address $2000) this results in up to 6 I/O buffers and thus up to 6 +concurrently open files. + +While using <tt/_heapadd()/ as described in the section above together with the +default I/O buffer allocation basically yields the same placement of I/O buffers +the primary benefit of <tt/apple2-iobuf-0800.o/ is a reduction in code size - +and thus program file size - of more than 1400 bytes. + +Using <tt/apple2-iobuf-0800.o/ is as simple as placing it on the linker command +line like this: + +<tscreen><verb> +cl65 -t apple2 -C apple2-system.cfg myprog.c apple2-iobuf-0800.o +</verb></tscreen> @@ -155,7 +320,7 @@ you cannot do it, it just means that there's no help. <tt/--start-addr $6000/ to reserve both hires pages. In memory constrained situations the memory from $803 to $1FFF - can be made available to a program by executing <tt/_heapadd ((void *) 0x0803, 0x17FD);/ + can be made available to a program by calling <tt/_heapadd ((void *) 0x0803, 0x17FD);/ at the beginning of <tt/main()/. Doing so is beneficial even if the program doesn't use the the heap explicitly because loading the driver (and in fact already opening the driver file) uses the heap implicitly. @@ -247,7 +412,7 @@ BASIC.SYSTEM) there are some limitations for DOS 3.3: may be converted to statically linked drivers using the co65 object-file converter. - <tag>Interrupts</tag> + <tag/Interrupts/ There's no <tt/interruptor/ support. Any attempt to use it yields the message 'FAILED TO ALLOC INTERRUPT' on program startup. This implicitly means that <tt/a2.stdmou.mou/ and <tt/a2.ssc.ser/ are not functional as they depend on @@ -260,20 +425,20 @@ BASIC.SYSTEM) there are some limitations for DOS 3.3: Although <htmlurl url="dio.html" name="DIO"> generally works with all ProDOS 8 devices, the function <htmlurl url="dio-3.html" name="dio_query_sectcount()"> -simply always return 280 (which is only correct for a 140KB disk). +simply always return 280 (which is only correct for a 140 KB disk). <sect1>Direct console I/O<p> <descrip> - <tag>Color</tag> + <tag/Color/ The Apple ][ has no color text mode. Therefore the functions <htmlurl url="funcref-205.html" name="textcolor()">, <htmlurl url="funcref-68.html" name="bgcolor()"> and <htmlurl url="funcref-69.html" name="bordercolor()"> have no effect. - <tag>Cursor</tag> + <tag/Cursor/ The Apple ][ has no hardware cursor. Therefore the function <htmlurl url="funcref-88.html" name="cursor()"> has no effect.