mirror of
https://github.com/deater/dos33fsprogs.git
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81 lines
1.3 KiB
ArmAsm
81 lines
1.3 KiB
ArmAsm
;clear_screens:
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; ;===================================
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; ; Clear top/bottom of page 0
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; ;===================================
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;
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; lda #$0
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; sta DRAW_PAGE
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; jsr clear_top
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; jsr clear_bottom
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; ;===================================
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; ; Clear top/bottom of page 1
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; ;===================================
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;
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; lda #$4
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; sta DRAW_PAGE
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; jsr clear_top
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; jsr clear_bottom
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;
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; rts
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;clear_bottoms:
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; lda DRAW_PAGE
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; pha
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;===================================
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; Clear bottom of page 0
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;===================================
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; lda #$0
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; sta DRAW_PAGE
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; jsr clear_bottom
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;===================================
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; Clear bottom of page 1
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;===================================
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; lda #$4
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; sta DRAW_PAGE
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; jsr clear_bottom
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; pla
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; sta DRAW_PAGE
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; rts
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;=========================================================
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; clear_bottom
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;=========================================================
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; clear bottom of draw page
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clear_bottom:
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clc ; 2
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lda DRAW_PAGE ; 3
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adc #6 ; 2
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sta __cbf2+2 ; 3
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sta __cbf2+5 ; 3
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adc #1 ; 2
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sta __cbf2+8 ; 3
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sta __cbf2+11 ; 3
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ldy #120 ; 2
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lda #$a0 ; Normal Space ; 2
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clear_bottom_fast_loop:
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__cbf2:
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sta $600,Y ; 5
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sta $680,Y ; 5
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sta $700,Y ; 5
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sta $780,Y ; 5
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dey ; 2
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cpy #80 ; 2
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bpl clear_bottom_fast_loop ; 2nt/3
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rts ; 6
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