mirror of
https://github.com/deater/dos33fsprogs.git
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128 lines
1.4 KiB
ArmAsm
128 lines
1.4 KiB
ArmAsm
; do a (hopefully fast) plasma
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; 151 -- original
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; 137 -- optimize generation
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.include "zp.inc"
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.include "hardware.inc"
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CTEMP = $FC
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SAVEOFF = $FD
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SAVEX = $FE
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SAVEY = $FF
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;================================
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; Clear screen and setup graphics
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;================================
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jsr SETGR
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lda #0
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sta DISP_PAGE
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lda #4
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sta DRAW_PAGE
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;col = ( 8.0 + (sintable[xx&0xf])
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; + 8.0 + (sintable[yy&0xf])
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; ) / 2;
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ldy #0
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sty SAVEOFF
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create_yloop:
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ldx #0
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create_xloop:
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; lda SAVEOFF
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; and #$f
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; tax
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clc
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lda #15
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adc sinetable,X
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adc sinetable,Y
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lsr
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lookup_smc:
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stx SAVEX
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ldx SAVEOFF
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sta lookup,X
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ldx SAVEX
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inc SAVEOFF
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inx
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cpx #16
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bne create_xloop
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iny
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cpy #16
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bne create_yloop
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forever_loop:
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; cycle colors
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ldx #0
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cycle_loop:
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inc lookup,X
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inx
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bne cycle_loop
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; plot
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ldx #0 ; YY=0
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plot_yloop:
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ldy #0 ; XX = 0
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plot_xloop:
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stx SAVEX ; SAVE YY
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sty SAVEY ; SAVE XX
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tya
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and #$f
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sta CTEMP
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txa
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and #$f
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asl
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asl
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asl
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asl
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ora CTEMP
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tax
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lda lookup,X
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and #$f
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lsr
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tax
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lda colorlookup,X
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jsr SETCOL
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lda SAVEX
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jsr PLOT ; plot at Y,A
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ldy SAVEY ; restore XX
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ldx SAVEX ; restore YY
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iny
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cpy #40
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bne plot_xloop
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inx
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cpx #40
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bne plot_yloop
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beq forever_loop
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sinetable:
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.byte $00,$03,$05,$07,$08,$07,$05,$03
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.byte $00,$FD,$FB,$F9,$F8,$F9,$FB,$FD
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colorlookup:
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;.byte $00,$00,$05,$05,$07,$07,$0f,$0f
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;.byte $07,$07,$06,$06,$02,$02,$05,$05
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.byte $00,$05,$07,$0f,$07,$06,$02,$05
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lookup:
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