dos33fsprogs/demos/lovebyte2021/tiny_triangles/tiny_triangles.s
2021-03-14 20:49:24 -04:00

62 lines
899 B
ArmAsm

GBASL = $26
GBASH = $27
HGRPAGE = $E6
HGR_BITS = $1C
HGR_X = $E0
HGR_Y = $E2
HGR_COLOR = $E4
PAGE0 = $C054
PAGE1 = $C055
HGR = $F3E2
HGR2 = $F3D8
HCLR = $F3F2
HPLOT0 = $F457 ;; plot at (Y,X), (A)
WAIT = $FCA8 ;; delay 1/2(26+27A+5A^2) us
.zeropage
.globalzp xx_smc,yy_smc
tiny:
jsr HGR2 ; clear page1
; A is 0 after
tiny_yloop:
; lda #0
; sta XX ; XX doesn't really matter where starts
; sta YY ; start at top of screen
tiny_xloop:
txa
; lda xx_smc+1
and yy_smc+1
beq store_color
lda #$7f
store_color:
sta HGR_COLOR
ldy #0
;xx_smc:
; ldx #0
yy_smc:
lda #0
jsr HPLOT0 ; plot at (Y,X), (A)
; at begin, stores A to HGR_Y
; X to HGR_X and Y to HGR_X+1
; destroys X,Y,A
; Y is XX/7
ldx HGR_X
inx
; inc xx_smc+1
bne tiny_xloop
inc yy_smc+1
bne tiny_xloop
; should we over-write brk handler to restart?