55 lines
1.8 KiB
NASM
55 lines
1.8 KiB
NASM
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; -------------------------------------------------------------------
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; this file is intended to be assembled with ACME.
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; It has not been tested with any other assemblers or linkers.
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; -------------------------------------------------------------------
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; -------------------------------------------------------------------
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; example usage of the standard decruncher
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; this program decrunches data to memory
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; -------------------------------------------------------------------
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; if decrunching forwards then the following line must be uncommented.
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;DECRUNCH_FORWARDS = 1
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!ifndef DECRUNCH_FORWARDS {
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DECRUNCH_FORWARDS = 0
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}
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; -------------------------------------------------------------------
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* = $0801
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!byte $0b,$08,<2019,>2019,$9e,$32,$30,$36,$31,0,0,0
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; -------------------------------------------------------------------
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; we begin here
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; -------------------------------------------------------------------
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!if DECRUNCH_FORWARDS = 0 {
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lda $04
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sta _byte_lo
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lda $05
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sta _byte_hi
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} else {
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lda $02
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sta _byte_lo
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lda $03
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sta _byte_hi
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}
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jmp exod_decrunch
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; -------------------------------------------------------------------
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exod_get_crunched_byte:
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!if DECRUNCH_FORWARDS = 0 {
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lda _byte_lo
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bne _byte_skip_hi
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dec _byte_hi
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_byte_skip_hi:
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dec _byte_lo
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}
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_byte_lo = * + 1
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_byte_hi = * + 2
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lda $ffff ; needs to be set correctly before
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!if DECRUNCH_FORWARDS != 0 {
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inc _byte_lo
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bne _byte_skip_hi
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inc _byte_hi
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_byte_skip_hi:
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}
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rts ; decrunch_file is called.
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; end_of_data needs to point to the address just after the address
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; of the last byte of crunched data.
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; -------------------------------------------------------------------
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!source "exodecrunch.asm"
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