1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
|
.DB $01, $02, $04, $08, $10, $20, $40, $80
.PADTO 0x0040
VBlank:
CALL =VBLANK_Entrypoint
RETI
.PADTO 0x0100
Start:
JP =Initialize_RAM
.PADTO 0x0104
Nintendo_Logo: ; The Nintendo logo must be stored in bytes 0x104-133
.DB $CE,$ED,$66,$66,$CC,$0D,$00,$0B,$03,$73,$00,$83,$00,$0C,$00,$0D
.DB $00,$08,$11,$1F,$88,$89,$00,$0E,$DC,$CC,$6E,$E6,$DD,$DD,$D9,$99
.DB $BB,$BB,$67,$63,$6E,$0E,$EC,$CC,$DD,$DC,$99,$9F,$BB,$B9,$33,$3E
.PADTO 0x0134
Checksum: ; The bytes 0x134-0x14d need to add up to 0xe7 (= 0xff - 0x19)
.DB $00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00,$00
.DB $00,$00,$00,$00,$00,$00,$00,$00,$00,$e7
Initialize_RAM:
Empty_WRAM:
LD HL, $C000
Empty_WRAM.loop:
XOR A
LD (HL+), a
LD a, $D0
CP h
JR NZ, =Empty_WRAM.loop
Wait_VBlank:
LD A, $reg_lcd_status
AND $03
CP $01
JR NZ, =Wait_VBlank
; LCDC
XOR A
LD $reg_lcd_controller, A
Empty_VRAM: ; (Clear screen)
LD hl, $VRAM_start ; We set the HL register to the start of VRAM
Empty_VRAM.loop:
XOR A
LD (HL+), a ; We set the memory pointed to by HL to 0 and increase HL
LD a, $a0
CP h ; Until h has reached $a0 ($a0000 is the end of VRAM)
JR NZ, =Empty_VRAM.loop
; BG Palette
LD A, $e4
LD $reg_bg_palette, A
; OBJ0 Palette
LD A, $e4
LD $reg_obj0_palette, A
; Interrupts
LD A, $01
LD $reg_interrupt_enable, A
JP =Entrypoint
|
