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|
SECTION "main",rom0
; set up stack
ld sp,$fffe
; clear vram ($8000–9fff)
xor a
ld hl,$9fff
vloop:
ld [hld],a
bit 7,h
jr nz,vloop
; set up audio
ld hl,$ff26
ld c,$11
ld a,$80
ld [hld],a
ld [$ff00+c],a
inc c
ld a,$f3
ld [$ff00+c],a
ld [hld],a
ld a,$77
ld [hl],a
; set background palette
ld a,%11111100
ld [$ff47],a
; convert and load logo data from cart into vram
ld hl,$0104 ; cart logo
push hl
ld de,logo
lastbranch:
ld a,[de]
inc de
cp [hl] ; compare cart logo to bootrom logo
jr nz,loop98
inc hl
ld a,l
cp $34
jr nz,lastbranch
ld b,$19
ld a,b
cloop:
add [hl]
inc hl
dec b
jr nz,cloop
add [hl]
jr nz,loop98
pop de
ld hl,$8010
loopf3:
ld a,[de]
call funca9
call funcaa
inc de
ld a,e
cp $34
jr nz,loopf3
ld a,$18
ld hl,$992f
loopf1:
ld c,$c
loop56:
ld [hld],a
dec a
jr z,loop09
dec c
jr nz,loop56
ld de,$ffec
add hl,de
jr loopf1
loop09:
ld h,a
ld a,$64
ld d,a
ld [$ff42],a
ld a,$91
ld [$ff40],a
inc b
loop6e:
ld e,2
call funcbc
ld c,$13
inc h
ld a,h
ld e,$83
cp $62
jr z,loop83
ld e,$c1
cp $64
jr nz,loop89
loop83:
ld a,e
ld [$ff00+c],a
inc c
ld a,$87
ld [$ff00+c],a
loop89:
ld a,[$ff42]
sub b
ld [$ff42],a
dec d
jr nz,loop6e
dec b
jr nz,end
ld d,$20
jr loop6e
loop98:
ld a,$91
ld [$ff40],a
loop9c:
ld e,$14
call funcbc
ld a,[$ff47]
xor $ff
ld [$ff47],a
jr loop9c
funca9:
ld c,a
funcaa:
ld b,4
dloop:
push bc
rl c
rla
pop bc
rl c
rla
dec b
jr nz,dloop
ld [hli],a
inc hl
ld [hli],a
inc hl
ret
funcbc:
ld c,$c
loopbe:
ld a,[$ff44]
cp $90
jr nz,loopbe
dec c
jr nz,loopbe
dec e
jr nz,funcbc
ret
logo:
INCLUDE "nintendo.s"
db $ff,$ff
end:
inc a
ld [$ff50],a ; turn off bootrom
|
