Game Boy >> Assembly

Object Attribute Memory(OAM)

---

參考資訊：
1. bgb
2. rgbds
3. gambatte
4. DMGreport

OBJ0~OBJ39，共40個OBJ可以使用


8x8、8x16


main.s

OAMRAM      equ $fe00
LCDC        equ $ff40
LCDCF_OBJ8  equ %00000000
LCDCF_OBJON equ %00000010
IE          equ $ffff
IEF_VBLANK  equ %00000001
 
section "vblank", rom0[$0040]
    reti
  
section "lcdc", rom0[$0048]
    reti
  
section "timer", rom0[$0050]
    reti
  
section "serial", rom0[$0058]
    reti
  
section "joypad", rom0[$0060]
    reti
  
section "entry", rom0[$0100]
    nop
    jp _start
  
section "header", rom0[$0104]
    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
    db "0123456789abcde"
    db 0
    db 0, 0
    db 0
    db 0
    db 0
    db 0
    db 1
    db $33
    db 0
    db 0
    dw 0
  
_start:
    di
    ld sp, $ffff
    ld a, IEF_VBLANK
    ld [IE], a
    ei

    halt
    halt

    ld a, [LCDC]
    or LCDCF_OBJON
    or LCDCF_OBJ8
    ld [LCDC], a

    ld hl, OAMRAM + 0
    ld [hl], 30
    ld hl, OAMRAM + 1
    ld [hl], 30
    ld hl, OAMRAM + 2
    ld [hl], $19
    ld hl, OAMRAM + 3
    ld [hl], 0

    jp @

設定OBJ0的位置(y:30, x:30)、CHR(0x19)、屬性(0)，CHR其實就是一般稱呼的Tile，而Sprite則是由Tile組合而成的圖形

完成


由於OAM並沒有全部被初始化，開機後的內容是隨機，這也是為何有很多雜點的原因

返回上一頁