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40 lines
575 B
ArmAsm
40 lines
575 B
ArmAsm
; try to get sine table from ROM
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sinetable=$6000
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costable_base = $F5BA
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rom_sine:
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;==========================================
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; create sinetable using ROM cosine table
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ldx #0
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ldy #$f
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sinetable_loop:
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lda costable_base+1,X
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force_zero:
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lsr ; rom value is *256
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lsr ; we want *32
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lsr
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sta sinetable+$10,X
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sta sinetable+$00,Y
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eor #$FF
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sec ; these aren't strictly necessary
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adc #$0 ; depending how accurate you want it
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sta sinetable+$30,X
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sta sinetable+$20,Y
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inx
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dey
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tya ; force a zero at end
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beq force_zero
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bpl sinetable_loop
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end:
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jmp end
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