mirror of
https://github.com/deater/dos33fsprogs.git
synced 2024-06-09 07:29:32 +00:00
109 lines
1.0 KiB
ArmAsm
109 lines
1.0 KiB
ArmAsm
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do_rotozoom:
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;=================================
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; main loop
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lda #0
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sta ANGLE
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sta SCALE_F
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sta FRAMEL
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lda #1
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sta SCALE_I
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main_loop:
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jsr rotozoom
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jsr page_flip
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;============================
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; wait for end
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;============================
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lda #47
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jsr wait_for_pattern
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bcc no_keypress
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rts
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no_keypress:
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clc
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lda FRAMEL
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adc direction
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sta FRAMEL
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cmp #$f8
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beq back_at_zero
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cmp #33
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beq at_far_end
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bne done_reverse
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back_at_zero:
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at_far_end:
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; change bg color
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lda roto_color_even_smc+1
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clc
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adc #$01
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and #$0f
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sta roto_color_even_smc+1
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lda roto_color_odd_smc+1
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clc
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adc #$10
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and #$f0
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sta roto_color_odd_smc+1
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; reverse direction
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lda direction
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eor #$ff
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clc
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adc #1
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sta direction
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lda scaleaddl
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eor #$ff
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clc
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adc #1
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sta scaleaddl
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lda scaleaddh
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eor #$ff
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adc #0
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sta scaleaddh
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done_reverse:
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clc
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lda ANGLE
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adc direction
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and #$1f
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sta ANGLE
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clc
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lda SCALE_F
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adc scaleaddl
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sta SCALE_F
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lda SCALE_I
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adc scaleaddh
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sta SCALE_I
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jmp main_loop
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direction: .byte $01
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scaleaddl: .byte $10
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scaleaddh: .byte $00
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