118 lines
1.9 KiB
ArmAsm
118 lines
1.9 KiB
ArmAsm
; Zooming Circles, based on the code in Hellmood's Memories
|
|
|
|
; by deater (Vince Weaver) <vince@deater.net>
|
|
|
|
; Zero Page
|
|
COLOR = $30
|
|
TEMP = $FA
|
|
TEMPY = $FB
|
|
FRAME = $FC
|
|
XSAVE = $FD
|
|
|
|
; Soft Switches
|
|
KEYPRESS= $C000
|
|
KEYRESET= $C010
|
|
SET_GR = $C050 ; Enable graphics
|
|
FULLGR = $C052 ; Full screen, no text
|
|
PAGE0 = $C054 ; Page0
|
|
PAGE1 = $C055 ; Page1
|
|
LORES = $C056 ; Enable LORES graphics
|
|
|
|
; ROM routines
|
|
|
|
PLOT = $F800 ; plot, horiz=y, vert=A (A trashed, XY Saved)
|
|
SETCOL = $F864
|
|
TEXT = $FB36 ;; Set text mode
|
|
SETGR = $FB40
|
|
HOME = $FC58 ;; Clear the text screen
|
|
WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us
|
|
|
|
|
|
; 103 bytes
|
|
|
|
.globalzp squares_table_y
|
|
.globalzp color_lookup
|
|
|
|
.zeropage
|
|
|
|
zooming_circles:
|
|
|
|
;===================
|
|
; init screen
|
|
jsr SETGR ; 3
|
|
bit FULLGR ; 3
|
|
;====
|
|
; 6
|
|
circle_forever:
|
|
|
|
inc FRAME ; 2
|
|
ldx #23 ; 2
|
|
;===
|
|
; 4
|
|
yloop:
|
|
ldy #19 ; 2
|
|
xloop:
|
|
|
|
clc ; 1
|
|
lda squares_table_y+4,y ; 3
|
|
asl ; 1
|
|
asl ; 1
|
|
adc squares_table_y,x ; 3
|
|
|
|
lsr ; 1
|
|
adc FRAME ; 2
|
|
and #$1f ; 2
|
|
|
|
lsr ; 1
|
|
lsr ; 1
|
|
lsr ; 1
|
|
stx XSAVE ; 2
|
|
tax ; 1
|
|
lda color_lookup,X ; 3
|
|
sta COLOR ; 2
|
|
ldx XSAVE ; 2
|
|
|
|
txa ; 1
|
|
jsr PLOT ; 3
|
|
|
|
|
|
|
|
dey ; 1
|
|
bpl xloop ; 2
|
|
|
|
dex ; 1
|
|
bpl yloop ; 2
|
|
|
|
bmi circle_forever ; 2
|
|
|
|
|
|
|
|
color_lookup:
|
|
.byte $00,$55,$00,$77
|
|
|
|
|
|
; 48 bytes
|
|
squares_table_y:
|
|
;.byte $24,$21,$1e,$1b,$19,$16,$14,$12
|
|
;.byte $10,$0e,$0c,$0a,$09,$07,$06,$05
|
|
;.byte $04,$03,$02,$01,$01,$00,$00,$00
|
|
|
|
.byte $00,$00,$00,$00,$01,$01,$02,$03
|
|
.byte $04,$05,$06,$07,$09,$0a,$0c,$0e
|
|
.byte $10,$12,$14,$16,$19,$1b,$1e,$21
|
|
|
|
|
|
|
|
|
|
; 40 bytes
|
|
;squares_table_x:
|
|
;.byte $71,$6a,$64,$5d,$57,$51,$4b,$45
|
|
;.byte $40,$3a,$35,$31,
|
|
;.byte $2c,$28,$24,$20
|
|
;.byte $1c,$19,$15,$12,$10,$0d,$0b,$09
|
|
;.byte $07,$05,$04,$02,$01,$01,$00,$00
|
|
;.byte $00,$00,$00,$01,$01,$02,$04,$05
|
|
;.byte $07,$09,$0b,$0d,$10,$12,$15,$19
|
|
;.byte $1c,$20,$24,$28 ;,$2c,$31,$35,$3a
|
|
;;.byte $40,$45,$4b,$51,$57,$5d,$64,$6a
|