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Although the primary target OS for the Apple II for sure isn't DOS 3.3 but ProDOS 8 the Apple II binary files contained a DOS 3.3 4-byte header. Recently I was made aware of the AppleSingle file format. That format is a much better way to transport Apple II meta data from the cc65 toolchain to the ProDOS 8 file system. Therefore I asked AppleCommander to support the AppleSingle file format. Now that there's an AppleCommander BETA with AppleSingle support it's the right time for this change. I bumped version to 2.17 because of this from the perspective of Apple II users of course incompatible change.
674 lines
22 KiB
Plaintext
674 lines
22 KiB
Plaintext
<!doctype linuxdoc system>
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<article>
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<title>Enhanced Apple //e specific information for cc65
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<author><url url="mailto:ol.sc@web.de" name="Oliver Schmidt">
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<date>2014-04-10
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<abstract>
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An overview over the enhanced Apple //e runtime system as it is
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implemented for the cc65 C compiler.
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</abstract>
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<!-- Table of contents -->
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<toc>
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<!-- Begin the document -->
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<sect>Overview<p>
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This file contains an overview of the enhanced Apple //e runtime system
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as it comes with the cc65 C compiler. It describes the memory layout,
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enhanced Apple //e specific header files, available drivers, and any
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pitfalls specific to that platform.
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Please note that enhanced Apple //e specific functions are just mentioned
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here, they are described in detail in the separate <url url="funcref.html"
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name="function reference">. Even functions marked as "platform dependent" may
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be available on more than one platform. Please see the function reference for
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more information.
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<sect>Binary format<p>
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The standard binary file format generated by the linker for the
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enhanced Apple //e target is an <url name="AppleSingle"
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url="http://kaiser-edv.de/documents/AppleSingle_AppleDouble.pdf"> file.
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The default load address is $803.
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<bf/AppleCommander 1.4.0/ or later (available at <url
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url="https://applecommander.github.io/">) includes the option <tt/-as/ that
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allows to put AppleSingle files onto disk images containing DOS 3.3 as well
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as ProDOS 8.
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<sect>Memory layout<p>
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In the standard setup, cc65 generated programs use the memory from
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$803 to $95FF, so 35.5 KB of RAM are available.
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Special locations:
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<descrip>
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<tag/Stack/
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The C runtime stack is located at HIMEM and grows downwards, regardless of
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how your linker config file is setup.
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<tag/Heap/
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The C heap is located at the end of the program and grows towards the C
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runtime stack.
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</descrip><p>
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While running <tt/main()/ the Language Card bank 2 is enabled for read access.
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However while running module constructors/destructors the Language Card is disabled.
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Enabling the Language Card allows to use it as additional memory for cc65
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generated code. However code is never automatically placed there. Rather code
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needs to be explicitly placed in the Language Card either per file by compiling
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with <tt/--code-name LC/ or per function by enclosing in <tt/#pragma code-name
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(push, "LC")/ and <tt/#pragma code-name (pop)/. In either case the cc65 runtime
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system takes care of actually moving the code into the Language Card.
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The amount of memory available in the Language Card for generated code depends
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on the <ref id="link-configs" name="linker configuration"> parameters. There are
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several usefull settings:
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<descrip>
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<tag>LC address: $D400, LC size: $C00</tag>
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For plain vanilla ProDOS 8 which doesn't actually use the Language Card bank 2
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memory from $D400 to $DFFF. This is the default setting.
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<tag>LC address: $D000, LC size: $1000</tag>
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For ProDOS 8 together with the function <tt/rebootafterexit()/. If a program
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doesn't quit to the ProDOS 8 dispatcher but rather reboots the machine after
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exit then a plain vanilla ProDOS 8 doesn't make use of the Language Card bank
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2 at all.
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<tag>LC address: $D000, LC size: $3000</tag>
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For plain vanilla DOS 3.3 which doesn't make use of the Language Card at all.
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</descrip><p>
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<sect>Linker configurations<label id="link-configs"><p>
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The ld65 linker comes with a default config file for the enhanced Apple //e,
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which is used via <tt/-t apple2enh/.
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The apple2enh package comes with additional secondary linker config files, which
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are used via <tt/-t apple2enh -C <configfile>/.
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<sect1>default config file (<tt/apple2enh.cfg/)<label id="apple-def-cfg"><p>
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Default configuration for a binary program.
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Parameters:
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<descrip>
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<tag><tt/STARTADDRESS:/ Program start address</tag>
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Default: $803. Use <tt/-S <addr>/ to set a different start address.
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<tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
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Default: Yes. Use <tt/-D __EXEHDR__=0/ to omit the AppleSingle header.
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<tag><tt/__STACKSIZE__:/ C runtime stack size</tag>
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Default: $800. Use <tt/-D __STACKSIZE__=<size>/ to set a different
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stack size.
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<tag><tt/__HIMEM__:/ Highest usable memory address presumed at link time</tag>
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Default: $9600. Use <tt/-D __HIMEM__=<addr>/ to set a different
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highest usable address.
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<tag><tt/__LCADDR__:/ Address of code in the Language Card</tag>
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Default: $D400. Use <tt/-D __LCADDR__=<addr>/ to set a different
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code address.
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<tag><tt/__LCSIZE__:/ Size of code in the Language Card</tag>
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Default: $C00. Use <tt/-D __LCSIZE__=<size>/ to set a different
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code size.
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</descrip><p>
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<sect1><tt/apple2enh-system.cfg/<label id="apple-sys-cfg"><p>
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Configuration for a system program running on ProDOS 8 and using the memory from
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$2000 to $BEFF.
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Parameters:
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<descrip>
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<tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
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Default: Yes. Use <tt/-D __EXEHDR__=0/ to omit the AppleSingle header.
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<tag><tt/__STACKSIZE__:/ C runtime stack size</tag>
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Default: $800. Use <tt/-D __STACKSIZE__=<size>/ to set a different
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stack size.
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<tag><tt/__LCADDR__:/ Address of code in the Language Card</tag>
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Default: $D400. Use <tt/-D __LCADDR__=<addr>/ to set a different
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code address.
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<tag><tt/__LCSIZE__:/ Size of code in the Language Card</tag>
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Default: $C00. Use <tt/-D __LCSIZE__=<size>/ to set a different
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code size.
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</descrip><p>
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<sect1><tt/apple2enh-hgr.cfg/<p>
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Configuration for a program including a hires page. See <tt>testcode/lib/apple/hgrtest.c</tt>
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for an example of such a program.
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Parameters:
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<descrip>
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<tag><tt/STARTADDRESS:/ Program start address</tag>
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Default: $803. Use <tt/-S <addr>/ to set a different start address.
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<tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
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Default: Yes. Use <tt/-D __EXEHDR__=0/ to omit the AppleSingle header.
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<tag><tt/__STACKSIZE__:/ C runtime stack size</tag>
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Default: $800. Use <tt/-D __STACKSIZE__=<size>/ to set a different
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stack size.
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<tag><tt/__HIMEM__:/ Highest usable memory address presumed at link time</tag>
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Default: $9600. Use <tt/-D __HIMEM__=<addr>/ to set a different
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highest usable address.
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<tag><tt/__LCADDR__:/ Address of code in the Language Card</tag>
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Default: $D400. Use <tt/-D __LCADDR__=<addr>/ to set a different
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code address.
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<tag><tt/__LCSIZE__:/ Size of code in the Language Card</tag>
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Default: $C00. Use <tt/-D __LCSIZE__=<size>/ to set a different
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code size.
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</descrip><p>
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<sect1><tt/apple2enh-overlay.cfg/<p>
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Configuration for an overlay program with up to nine overlays. The overlay files
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don't include the AppleSingle header. See <tt>samples/overlaydemo.c</tt> for more
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information on overlays.
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Parameters:
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<descrip>
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<tag><tt/STARTADDRESS:/ Program start address</tag>
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Default: $803. Use <tt/-S <addr>/ to set a different start address.
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<tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
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Default: Yes. Use <tt/-D __EXEHDR__=0/ to omit the AppleSingle header.
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<tag><tt/__STACKSIZE__:/ C runtime stack size</tag>
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Default: $800. Use <tt/-D __STACKSIZE__=<size>/ to set a different
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stack size.
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<tag><tt/__HIMEM__:/ Highest usable memory address presumed at link time</tag>
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Default: $9600. Use <tt/-D __HIMEM__=<addr>/ to set a different
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highest usable address.
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<tag><tt/__LCADDR__:/ Address of code in the Language Card</tag>
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Default: $D400. Use <tt/-D __LCADDR__=<addr>/ to set a different
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code address.
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<tag><tt/__LCSIZE__:/ Size of code in the Language Card</tag>
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Default: $C00. Use <tt/-D __LCSIZE__=<size>/ to set a different
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code size.
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<tag><tt/__OVERLAYSIZE__:/ Size of code in the overlays</tag>
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Default: $1000. Use <tt/-D __OVERLAYSIZE__=<size>/ to set a different
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code size.
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</descrip><p>
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<sect1><tt/apple2enh-asm.cfg/<p>
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Configuration for an assembler program that doesn't need a special setup.
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Parameters:
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<descrip>
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<tag><tt/STARTADDRESS:/ Program start address</tag>
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Default: $803. Use <tt/-S <addr>/ to set a different start address.
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<tag><tt/__EXEHDR__:/ AppleSingle executable file header</tag>
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Default: No. Use <tt/-u __EXEHDR__ apple2enh.lib/ to add the AppleSingle header.
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</descrip><p>
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<sect>ProDOS 8 system programs<p>
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ProDOS 8 system programs are always loaded to the start address $2000.
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For cc65 programs this means that the 6 KB from $800 to $2000 are
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by default unused. There are however several options to make use of that memory
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range.
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<sect1>LOADER.SYSTEM<p>
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The easiest (and for really large programs in fact the only) way to have a cc65
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program use the memory from $800 to $2000 is to link it as binary
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(as opposed to system) program using the default linker configuration
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<ref id="apple-def-cfg" name="apple2enh.cfg"> with <tt/__HIMEM__/set to $BF00
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and load it with the LOADER.SYSTEM utility. The program then works like a system
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program (i.e. quits to the ProDOS dispatcher).
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Using LOADER.SYSTEM is as simple as copying it to the ProDOS 8 directory of the
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program to load under name <program>.SYSTEM as a system program. For
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example the program <tt/MYPROG/ is loaded by <tt/MYPROG.SYSTEM/. The right
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AppleCommander option to put LOADER.SYSTEM on a ProDOS 8 disk image is <tt/-p/.
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<sect1>Heap<p>
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If the cc65 program can be successfully linked as system program using the linker
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configuration <ref id="apple-sys-cfg" name="apple2enh-system.cfg">, but
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uses the heap either explicitly or implicitly (i.e. by loading a driver) then
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the memory from $800 to $2000 can be added to the heap by calling
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<tt/_heapadd ((void *) 0x0800, 0x1800);/ at the beginning of <tt/main()/.
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<sect1>ProDOS 8 I/O buffers<p>
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ProDOS 8 requires for every open file a page-aligned 1 KB I/O buffer. By default
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these buffers are allocated by the cc65 runtime system on the heap using
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<tt/posix_memalign()/. While this is generally the best solution it means quite
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some overhead for (especially rather small) cc65 programs which do open files
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but don't make use of the heap otherwise.
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The apple2enh package comes with the alternative ProDOS 8 I/O buffer allocation
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module <tt/apple2enh-iobuf-0800.o/ which uses the memory between $800 and
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the program start address for the 1 KB I/O buffers. For system programs (with
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start address $2000) this results in up to 6 I/O buffers and thus up to 6
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concurrently open files.
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While using <tt/_heapadd()/ as described in the section above together with the
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default I/O buffer allocation basically yields the same placement of I/O buffers
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in memory the primary benefit of <tt/apple2enh-iobuf-0800.o/ is a reduction in code
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size - and thus program file size - of more than 1400 bytes.
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Using <tt/apple2enh-iobuf-0800.o/ is as simple as placing it on the linker command
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line like this:
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<tscreen><verb>
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cl65 -t apple2enh -C apple2enh-system.cfg myprog.c apple2enh-iobuf-0800.o
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</verb></tscreen>
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<sect>Platform specific header files<p>
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Programs containing enhanced Apple //e specific code may use the
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<tt/apple2enh.h/ header file.
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<sect1>Enhanced Apple //e specific functions<p>
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The functions listed below are special for the enhanced Apple //e. See
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the <url url="funcref.html" name="function reference"> for declaration and
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usage.
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<itemize>
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<item>_auxtype
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<item>_dos_type
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<item>_filetype
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<item>get_ostype
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<item>rebootafterexit
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<item>ser_apple2_slot
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<item>textframe
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<item>textframexy
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<item>tgi_apple2_mix
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<item>videomode
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</itemize>
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<sect1>Hardware access<p>
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There's currently no support for direct hardware access. This does not mean
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you cannot do it, it just means that there's no help.
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<sect>Loadable drivers<p>
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The names in the parentheses denote the symbols to be used for static linking of the drivers.
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<sect1>Graphics drivers<p>
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<descrip>
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<tag><tt/a2e.lo.tgi (a2e_lo_tgi)/</tag>
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This driver features a resolution of 40×48 with 16 colors.
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The function <tt/tgi_apple2_mix()/ allows to activate 4 lines of text. The
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function clears the corresponding area at the bottom of the screen.
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<tag><tt/a2e.hi.tgi (a2e_hi_tgi)/</tag>
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This driver features a resolution of 280×192 with 8 colors and two
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hires pages. Note that programs using this driver will have to be linked
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with <tt/-S $4000/ to reserve the first hires page or with <tt/-S $6000/
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to reserve both hires pages.
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Note that the second hires page is only available if the text display is not in
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80 column mode. This can be asserted by calling <tt/videomode (VIDEOMODE_40COL);/
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before installing the driver.
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The function <tt/tgi_apple2_mix()/ allows to activate 4 lines of text. The
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function doesn't clear the corresponding area at the bottom of the screen.
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In memory constrained situations the memory from $803 to $1FFF
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can be made available to a program by calling <tt/_heapadd ((void *) 0x0803, 0x17FD);/
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at the beginning of <tt/main()/. Doing so is beneficial even if the program
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doesn't use the the heap explicitly because loading the driver (and in fact
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already opening the driver file) uses the heap implicitly.
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</descrip><p>
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<sect1>Extended memory drivers<p>
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<descrip>
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<tag><tt/a2e.auxmem.emd (a2e_auxmem_emd)/</tag>
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Gives access to 47.5 KB RAM (190 pages of 256 bytes each) on an Extended
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80-Column Text Card.
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Note that this driver doesn't check for the actual existence of the memory
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and that it doesn't check for ProDOS 8 RAM disk content!
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</descrip><p>
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<sect1>Joystick drivers<p>
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<descrip>
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<tag><tt/a2e.stdjoy.joy (a2e_stdjoy_joy)/</tag>
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Supports up to two standard analog joysticks connected to the game port of
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the enhanced Apple //e.
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</descrip><p>
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<sect1>Mouse drivers<p>
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<descrip>
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<tag><tt/a2e.stdmou.mou (a2e_stdmou_mou)/</tag>
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Driver for the AppleMouse II Card. Searches all Apple II slots
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for an AppleMouse II Card compatible firmware. The default bounding
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box is [0..279,0..191].
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Note that the enhanced Apple //e default mouse callbacks support
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text mode only.
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</descrip><p>
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<sect1>RS232 device drivers<p>
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<descrip>
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<tag><tt/a2e.ssc.ser (a2e_ssc_ser)/</tag>
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Driver for the Apple II Super Serial Card. Supports up to 19200 baud,
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hardware flow control (RTS/CTS) and interrupt driven receives. Note
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that because of the peculiarities of the 6551 chip transmits are not
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interrupt driven, and the transceiver blocks if the receiver asserts
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flow control because of a full buffer.
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The driver defaults to slot 2. Call <tt/ser_apple2_slot()/ prior to
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<tt/ser_open()/ in order to select a different slot. <tt/ser_apple2_slot()/
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succeeds for all Apple II slots, but <tt/ser_open()/ fails with
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<tt/SER_ERR_NO_DEVICE/ if there's no SSC firmware found in the selected slot.
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</descrip><p>
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<sect>Limitations<p>
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<sect1>DOS 3.3<p>
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Although the standard binaries generated by the linker for the enhanced Apple //e
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generally run both on DOS 3.3 (with Applesoft BASIC) and on ProDOS 8 (with
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BASIC.SYSTEM) there are some limitations for DOS 3.3:
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<descrip>
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<tag>Disk File I/O</tag>
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There's no disk file I/O support. Any attempt to use it yields an error with
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<tt/errno/ set to <tt/ENOSYS/. This implicitly means that loadable drivers
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are in general not functional as they depend on disk file I/O. Therefore the statically
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linked drivers have to be used instead.
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<tag/Interrupts/
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There's no <tt/interruptor/ support. Any attempt to use it yields the message
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'Failed to alloc interrupt' on program startup. This implicitly means that
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mouse and RS232 device drivers are not functional as they depend on interrupts.
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</descrip><p>
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<sect1>Direct console I/O<p>
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<descrip>
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<tag/Color/
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The enhanced Apple //e has no color text mode. Therefore the functions
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textcolor(), bgcolor() and bordercolor() have no effect.
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</descrip><p>
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<sect>Other hints<p>
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<sect1>Passing arguments to the program<p>
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Command line arguments can be passed to <tt/main()/ after BLOAD. Since this is not
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supported by BASIC, the following syntax was chosen:
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<tscreen><verb>
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]CALL2051:REM ARG1 " ARG2 IS QUOTED" ARG3 "" ARG5
|
|
</verb></tscreen>
|
|
|
|
<enum>
|
|
<item>Arguments are separated by spaces.
|
|
<item>Arguments may be quoted.
|
|
<item>Leading and trailing spaces around an argument are ignored. Spaces within
|
|
a quoted argument are allowed.
|
|
<item>The first argument passed to <tt/main/ is the program name.
|
|
<item>A maximum number of 10 arguments (including the program name) are
|
|
supported.
|
|
</enum>
|
|
|
|
|
|
<sect1>Function keys<p>
|
|
|
|
These are defined to be OpenApple + number key.
|
|
|
|
|
|
<sect1>Interrupts<p>
|
|
|
|
The runtime for the enhanced Apple //e uses routines marked as
|
|
<tt/.INTERRUPTOR/ for ProDOS 8 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 <url
|
|
url="ca65.html" name="assembler manual">.
|
|
|
|
|
|
<sect1>DIO<p>
|
|
|
|
<descrip>
|
|
|
|
<tag/Drive ID/
|
|
The function <url url="dio.html#s1" name="dio_open()"> has the single
|
|
parameter <tt/device/ to identify the device to be opened. Therefore an
|
|
Apple II slot and drive pair is mapped to that <tt/device/ according
|
|
to the formula
|
|
|
|
<tscreen>
|
|
device = slot + (drive - 1) * 8
|
|
</tscreen>
|
|
|
|
so that for example slot 6 drive 2 is mapped to <tt/device/ 14.
|
|
|
|
<tag/Sector count/
|
|
The function <url url="dio.html#s3" name="dio_query_sectcount()"> returns
|
|
the correct sector count for all ProDOS 8 disks. However for any non-ProDOS 8
|
|
disk it simply always returns 280 (which is only correct for a 140 KB disk).
|
|
This condition is indicated by the <tt/_oserror/ value 82.
|
|
|
|
</descrip><p>
|
|
|
|
|
|
<sect1>Specifying file types for fopen<p>
|
|
|
|
<descrip>
|
|
|
|
<tag>Explanation of File Types</tag>
|
|
|
|
ProDOS associates a file type and an auxiliary type with each file.
|
|
These type specifications are separate from the file's name, unlike
|
|
Windows which uses the file name's suffix (a.k.a.
|
|
extension) to specify the file type. For example, <tt/.exe/,
|
|
<tt/.doc/, or <tt/.bat/.
|
|
The ProDOS low-level
|
|
Machine-Language Interface (MLI) functions for creating and opening
|
|
files require these types to be specified. And if they don't match
|
|
with the file being opened, the operation may fail.
|
|
|
|
In contrast, the ISO C function <tt/fopen()/ and the POSIX function
|
|
<tt/open()/ have no parameter to specify either a file type or an
|
|
auxiliary type. Therefore, some additional mechanism for specifying
|
|
the file types is needed.
|
|
|
|
<tag>Specifying the File Type and Auxiliary Type</tag>
|
|
|
|
There are two global variables provided that allow the file type
|
|
and auxiliary type to be specified before a call to <tt/fopen()/
|
|
or <tt/open()/. They are defined in <tt/apple2_filetype.h/:
|
|
|
|
<tscreen>
|
|
<verb>
|
|
extern unsigned char _filetype; /* Default: PRODOS_T_BIN */
|
|
extern unsigned int _auxtype; /* Default: 0 */
|
|
</verb>
|
|
</tscreen>
|
|
|
|
The header file <tt/apple2_filetype.h/ also defines many values
|
|
that can be used to set these variables. It is included in
|
|
<tt/apple2.h/, which is in turn included in <tt/apple2enh.h/.
|
|
So it isn't necessary to include it directly. Just
|
|
include one of <tt/apple2.h/ or <tt/apple2enh.h/.
|
|
|
|
<tag>Example</tag>
|
|
|
|
A text file cannot be created with just the
|
|
standard C functions because they default to the binary type
|
|
<tt/PRODOS_T_BIN/. The <tt/_filetype/ variable must be set to
|
|
<tt/PRODOS_T_TXT/ to create a text file.
|
|
|
|
For a text file,
|
|
<tt/_auxtype/ specifies the record length. A zero record
|
|
length text file is referred to as a sequential text file.
|
|
This is equivalent to text files on
|
|
other operating systems, except that the line terminator is a
|
|
carriage return instead of a line-feed (Linux/BSD/MacOS) or
|
|
carriage return, line-feed pair (Windows).
|
|
|
|
The "sequential" text file terminology is in contrast to a
|
|
"random-access" text file which would
|
|
have a fixed-length, non-zero record length, so that the
|
|
file position of any individual record can be calculated.
|
|
|
|
For this example, the
|
|
<tt/_auxtype/ does not need to be set because it defaults to
|
|
the desired value, which is zero. To be more explicit,
|
|
<tt/_auxtype/ can also be set to <tt/PRODOS_AUX_T_TXT_SEQ/
|
|
which is defined as zero.
|
|
|
|
<tscreen>
|
|
<verb>
|
|
#include <stdio.h>
|
|
#include <string.h>
|
|
#include <errno.h>
|
|
#include <apple2.h>
|
|
|
|
void main(void)
|
|
{
|
|
FILE *out;
|
|
char *name = "MY.FAVS";
|
|
|
|
/*-----------------------------*/
|
|
|
|
_filetype = PRODOS_T_TXT;
|
|
_auxtype = PRODOS_AUX_T_TXT_SEQ;
|
|
|
|
/*-----------------------------*/
|
|
|
|
if ((out = fopen(name, "w")) != NULL) {
|
|
fputs("Jorah Mormont\r", out);
|
|
fputs("Brienne of Tarth\r", out);
|
|
fputs("Daenerys Targaryen\r", out);
|
|
fputs("Sandor Clegane\r", out);
|
|
if (fclose(out) == EOF) {
|
|
fprintf(stderr, "fclose failed for %s: %s", name, strerror(errno));
|
|
}
|
|
}
|
|
else {
|
|
fprintf(stderr, "fopen failed for %s: %s", name, strerror(errno));
|
|
}
|
|
}
|
|
</verb>
|
|
</tscreen>
|
|
|
|
</descrip><p>
|
|
|
|
|
|
<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>
|