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58 lines
831 B
ArmAsm
58 lines
831 B
ArmAsm
; shimmery blue pattern
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even_lookup=$f000
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odd_lookup=$f100
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staggered:
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; jsr HGR2 ; after, A=0, Y=0
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; tax ; init X to 0
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; set earlier
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; ldx #0
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; stx INDEXL ; set INDEXL to 0
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; pulse loop horizontal
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outer_loop:
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lda #$20 ; reset INDEXH to begin page1
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sta INDEXH
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inner_loop:
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lda even_lookup,X ; get even color
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sta (INDEXL),Y ; store it to memory
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iny
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lda odd_lookup,X ; get odd color
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sta (INDEXL),Y ; store it to memory
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iny
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bne inner_loop ; repeat for 256
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inc INDEXH ; point to next page
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inx ; point to next lookup
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txa ; wrap to 0..7
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and #$7
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tax
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lda #$40 ; see if done
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cmp INDEXH
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bne inner_loop
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; lda #100 ; A is $40 here
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jsr WAIT ; pause a bit
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; A is 0 here
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inx ; offset next FRAME
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; if FRAMEH is 4 then done
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lda FRAMEH
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cmp #4
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bne outer_loop
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