dos33fsprogs/demos/l/fuzzball_32/fuzzball.s
2022-01-23 21:56:02 -05:00

51 lines
776 B
ArmAsm

; Fuzzball -- a 32 byte Intro for Apple II
; this one was an accident, it ends up walking through memory
; a page at a time and using it as a shape table
; by Deater / dSr
; zero page locations
HGR_SCALE = $E7
; softswtich
SPEAKER = $C030
; ROM calls
HGR2 = $F3D8
HPOSN = $F411
XDRAW0 = $F65D
.zeropage
tiny_tiny:
jsr HGR2 ; Hi-res graphics, no text at bottom
; Y=0, A=0 after this call
iny ; #1
sty HGR_SCALE
tiny_loop:
; move back to center of screen
ldy #0 ; Y always 0
ldx #140
lda #96
jsr HPOSN ; X= (y,x) Y=(a)
bit SPEAKER ; click the speaker
rot_smc:
lda #0 ; ROT=0
tay ; ldy #>shape_table
; X is 140 here
jsr XDRAW0 ; XDRAW 1 AT X,Y
; Both A and X are 0 at exit
inc rot_smc+1
jmp tiny_loop ; use BVC to save byte?