mirror of https://github.com/a2-4am/4cade.git
91 lines
1.8 KiB
Plaintext
91 lines
1.8 KiB
Plaintext
;license:MIT
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;(c) 2019 by 4am
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;
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!cpu 6502
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!to "build/FX.INDEXED/ARROW",plain
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*=$6000
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y = $fc
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row = $fd
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col = $fe
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counter = $ff
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!source "src/fx/macros.a"
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!source "src/constants.a"
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lda #(40+12)
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sta counter
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lda #39
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sta col
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ColLoop
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lda #11
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sta row
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ldy col
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sty y
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jsr WaitForVBL
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RowLoop
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; check if this column is visible
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ldy y
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+IS_Y_OFFSCREEN
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bcs @skip1
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; do top half of arrow
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+SWITCH_TO_MASKS copymasks1
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lda row
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jsr HGRBlockCopyWithMask
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; do bottom half of arrow (opposing row, same col)
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+SWITCH_TO_MASKS copymasks4
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lda #23
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sec
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sbc row
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jsr HGRBlockCopyWithMask
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@skip1
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; now check if *this* column is visible
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iny
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sty y
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+IS_Y_OFFSCREEN
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bcs @nextrow
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; do top half of arrow
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lda row
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jsr HGRBlockCopy
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; do bottom half of arrow
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lda #23
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sec
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sbc row
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jsr HGRBlockCopy
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@nextrow
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dec row
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+LBPL RowLoop
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lda $c000
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bmi @exit
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dec col
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dec counter
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+LBNE ColLoop
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@exit jmp UnwaitForVBL
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copymasks1
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!byte %11111111
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!byte %11111110
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!byte %11111100
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!byte %11111000
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!byte %11110000
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!byte %11100000
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!byte %11000000
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!byte %10000000
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copymasks4
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!byte %10000000
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!byte %11000000
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!byte %11100000
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!byte %11110000
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!byte %11111000
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!byte %11111100
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!byte %11111110
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!byte %11111111
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+HGR_BLOCK_COPY_ROUTINES
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+HGR_COPY_MASK_ROUTINES
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