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49 lines
697 B
ArmAsm
49 lines
697 B
ArmAsm
; draws a circle pattern
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opener:
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; A=0 from HGR
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lda #$20
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sta HGR_SCALE
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jsr HGR
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sta HGR_ROTATION
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; A and Y are 0 here.
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; X is left behind by the boot process?
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tiny_loop:
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tay
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; ldy #0
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ldx #140
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lda #96
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jsr HPOSN ; set screen position to X= (y,x) Y=(a)
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; saves X,Y,A to zero page
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; after Y= orig X/7
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; A and X are ??
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ldx #<our_shape ; load $E2 into A, X, and Y
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ldy #>our_shape ; our shape table is in ROM at $E2E2
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inc HGR_ROTATION
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lda HGR_ROTATION
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cmp #$40
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beq done_circle
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jsr XDRAW0 ; XDRAW 1 AT X,Y
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; Both A and X are 0 at exit
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; Z flag set on exit
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; Y varies
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beq tiny_loop ; bra
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done_circle:
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lda #250
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jsr WAIT
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; rts
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our_shape = $E2E2
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