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|
cpu gameboy
option output-file,gb.gb
option output-format,gameboy
;option gameboy-irq,vbl,vbl_code
VRAM equ $8000
SCRN equ $9800
OAM equ $fe00
LCDC equ $ff40
STAT equ $ff41
BGRDPAL equ $ff47
OBJ0PAL equ $ff48
OBJ1PAL equ $ff49
CURLINE equ $ff44
READY equ $ff81
XPOS equ $ff82
VBLANK macro
push af
.wait
ldh a,(CURLINE)
cp 144
jr nz,wait
pop af
endm
;
; **********
; CODE START
; **********
;
org $150
di
xor a
ldh (READY),a
ld sp,$fffe
; Set LCD so only sprites show
;
VBLANK
ld a,$81
ldh (LCDC),a
ld a,$10
ldh (STAT),a
ld a,$e4
ldh (BGRDPAL),a
ldh (OBJ0PAL),a
ldh (OBJ1PAL),a
; Copy to VRAM
;
ld hl,VRAM
ld de,sprite
ld c,16
VBLANK
.copy
ld a,(de)
ld (hl+),a
inc de
dec c
jr nz,copy
ld a,1
ldh (READY),a
ei
VBLANK
; Set sprite numbers
;
xor a
ld (OAM+2),a
ld (OAM+6),a
ld (OAM+10),a
; Set sprite flags
;
ld a,$80
ld (OAM+3),a
ld (OAM+7),a
ld (OAM+11),a
.idle
VBLANK
ldh a,(XPOS)
inc a
ldh (XPOS),a
ld (OAM),a
ld (OAM+1),a
add 20
ld (OAM+4),a
ld (OAM+5),a
add 33
ld (OAM+8),a
ld (OAM+9),a
jr idle
vbl_code:
ldh a,(READY)
or a
jr z,finish
ldh a,(XPOS)
inc a
ldh (XPOS),a
ld (OAM),a
ld (OAM+1),a
xor a
ld (OAM+2),a
ld (OAM+3),a
.finish
reti
sprite:
defb $ff,$ff
defb $00,00
defb $ff,$ff
defb $00,00
defb $ff,$ff
defb $00,00
defb $ff,$ff
defb $00,00
defb $ff,$ff
defb $00,00
|
