2012-06-13 07:17:41 +00:00
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This directory holds files likely to be of use to you in developing your own
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programs. The contents of each file is summarized below.
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c64_0.oph: A Commodore 64 equivalent to a modern compiler's "crt0.s" - it
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contains a .PRG file header, a short BASIC program that launches
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the machine language program, and a prologue and epilogue that
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prepare memory for your use and then clean it up again when you
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2014-05-14 14:03:46 +00:00
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are done. Memory locations $02 through $8F on the zero page are
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2012-06-13 07:17:41 +00:00
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available for your use, and the program lives at the beginning
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2014-05-14 14:03:46 +00:00
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a contiguous block of RAM from $0800 through $CFFF. The BASIC
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2012-06-13 07:17:41 +00:00
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ROM is swapped out of memory (leaving $A000-$BFFF as RAM) for
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2014-05-14 14:03:46 +00:00
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the duration of your program. BASIC's working storage on the
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zero page is backed up in the RAM underneath the KERNAL ROM
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while your program runs.
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2012-06-13 07:17:41 +00:00
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c64kernal.oph: A collection of standard aliases for the KERNAL routines on the
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Commodore 64. Names for these routines have been chosen to match
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the Commodore 64 Programmer's Reference Guide. Additional useful
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constants are defined for the character codes for color changes
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and case-changing.
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2014-05-24 14:21:37 +00:00
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libbasic64.oph:A still-experimental set of macros and routines for exploiting
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the software floating point routines in the Commodore 64
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BASIC ROM.
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c64header.oph: A much simpler Commodore 64 header that does nothing but jump
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directly to your code. Useful for small programs or those that
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intend to interface with BASIC.
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vic20.oph: A simple header for the unexpanded VIC-20. Equivalent in
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behavior to c64header.oph.
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vic20x.oph: A simple header like the two above, but for expanded VIC-20.
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2012-06-13 07:17:41 +00:00
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nes.oph: A somewhat skeletal collection of aliases for the PPU registers
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on the Nintendo Entertainment System. These names were chosen
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to match the constant names given on the NESdev Wiki.
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stella.oph: A collection of aliases for the registers of the Atari 2600.
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These names were taken from the "Stella Programmer's Guide" and
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are in wide use amongst developers and code analysts alike.
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