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|
;
; This example is poor, and leaves lots of junk lymg in memory.
; Still, it works enough to test
;
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
ISWITCH equ $ffff
BGRDPAL equ $ff47
OBJ0PAL equ $ff48
OBJ1PAL equ $ff49
CURLINE equ $ff44
XPOS equ $ff82
VBLANK macro
push af
.wait
ldh a,(CURLINE)
cp 144
jr nz,wait
pop af
endm
;
; **********
; CODE START
; **********
;
org $150
di
ld sp,$fffe
; Switch of display during setup
;
VBLANK
xor a
ld (LCDC),a
ld (XPOS),a
ld a,$e4
ldh (OBJ0PAL),a
ldh (OBJ1PAL),a
swap a
ldh (BGRDPAL),a
; Copy to VRAM and set up
;
ld hl,VRAM
ld de,sprite
ld c,16
.copy
ld a,(de)
ld (hl+),a
inc de
dec c
jr nz,copy
; 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
; Set LCD back on
;
ld a,$83
ldh (LCDC),a
; Activate VBL
;
ld a,1
ldh (ISWITCH),a
ei
.idle
halt
nop
jr idle
vbl_code:
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
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
;
; Assembly checks
;
stop
swap a
swap b
swap c
swap d
swap e
swap h
swap l
swap (hl)
ld a,(hl+)
ld a,(hli)
ldi a,(hl)
ld a,(hl-)
ld a,(hld)
ldd a,(hl)
|
