158 lines
2.5 KiB
ArmAsm
158 lines
2.5 KiB
ArmAsm
; Zooming Circles, based on the code in Hellmood's Memories
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; by deater (Vince Weaver) <vince@deater.net>
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; Zero Page
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BASL = $28
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BASH = $29
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H2 = $2C
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COLOR = $30
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X1 = $F0
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X2 = $F1
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Y1 = $F2
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Y2 = $F3
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TEMP = $FA
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TEMPY = $FB
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FRAME = $FC
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TEMPX = $FD
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; Soft Switches
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KEYPRESS= $C000
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KEYRESET= $C010
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SET_GR = $C050 ; Enable graphics
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FULLGR = $C052 ; Full screen, no text
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PAGE0 = $C054 ; Page0
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PAGE1 = $C055 ; Page1
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LORES = $C056 ; Enable LORES graphics
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; ROM routines
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PLOT = $F800 ; plot, horiz=y, vert=A (A trashed, XY Saved)
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SETCOL = $F864
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TEXT = $FB36 ;; Set text mode
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BASCALC = $FBC1
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SETGR = $FB40
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HOME = $FC58 ;; Clear the text screen
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WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us
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HLINE = $F819
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; 103 bytes
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; attempted HLINE, not much help (122 bytes, slow)
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; quad plot, also 122
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.globalzp squares_table_y
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.globalzp color_lookup
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.globalzp smc1,smc2,smc3,smc4
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.zeropage
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zooming_circles:
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;===================
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; init screen
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jsr SETGR ; 3
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bit FULLGR ; 3
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;====
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; 6
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circle_forever:
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inc FRAME ; 2
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ldx #24 ; 2
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stx Y2 ; 2
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dex ; 1
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yloop:
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ldy #20 ; 2
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sty X2 ; 2
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dey ; 1
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xloop:
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clc ; 1
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lda squares_table_y+4,y ; 3
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asl ; 1
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asl ; 1
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adc squares_table_y,x ; 2
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lsr ; 1
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adc FRAME ; 2
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and #$1f ; 2
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; and #$18
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; 00, 10 = black
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; 01 = grey 55 or aa
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; 11 = light blue 77
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lsr ; 1
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lsr ; 1
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lsr ; 1
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sty TEMPY ; 2
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tay ; 1
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lda color_lookup,Y ; 3
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sta COLOR ; 2
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ldy X2 ; Y==X2 ; 2
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txa ; A==Y1 ; 1
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jsr PLOT ; (X2,Y1) ; 3
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lda Y2 ; A==Y2 ; 2
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jsr PLOT ; (X2,Y2) ; 3
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ldy TEMPY ; Y==X1 ; 2
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txa ; A==Y1 ; 1
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jsr PLOT ; (X1,Y1) ; 3
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lda Y2 ; A==Y2 ; 2
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jsr PLOT ; (X1,Y2) ; 3
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inc X2 ; 2
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dey ; 1
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bpl xloop ; 2
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inc Y2 ; 2
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dex ; 1
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bpl yloop ; 2
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bmi circle_forever ; 2
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; 24 bytes
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squares_table_y:
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.byte $24,$21,$1e,$1b,$19,$16,$14,$12
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.byte $10,$0e,$0c,$0a,$09,$07,$06,$05
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.byte $04,$03,$02,$01,$01,$00,$00
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color_lookup:
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.byte $00 ; also last byte of squares table
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.byte $55,$00,$77
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;.byte $00,$00,$00,$00,$01,$01,$02,$03
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;.byte $04,$05,$06,$07,$09,$0a,$0c,$0e
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;.byte $10,$12,$14,$16,$19,$1b,$1e,$21
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; 40 bytes
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;squares_table_x:
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;.byte $71,$6a,$64,$5d,$57,$51,$4b,$45
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;.byte $40,$3a,$35,$31,
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;.byte $2c,$28,$24,$20
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;.byte $1c,$19,$15,$12,$10,$0d,$0b,$09
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;.byte $07,$05,$04,$02,$01,$01,$00,$00
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;.byte $00,$00,$00,$01,$01,$02,$04,$05
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;.byte $07,$09,$0b,$0d,$10,$12,$15,$19
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;.byte $1c,$20,$24,$28 ;,$2c,$31,$35,$3a
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;;.byte $40,$45,$4b,$51,$57,$5d,$64,$6a
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