Game Boy >> Assembly

Character RAM(Tile)

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

每個像素使用2bits表示(上下bit)


main.s

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 d, 16
    ld bc, tile
    ld hl, $8000
copy_tile:
    ld a, [bc]
    ld [hl+], a
    inc bc
    dec d
    jr nz, copy_tile

    jp @
 
tile:
    db %11111111
    db %11111111
    db %01111110
    db %01111110
    db %00111100
    db %00111100
    db %00011000
    db %00011000
    db %00011000
    db %00011000
    db %00111100
    db %00111100
    db %01111110
    db %01111110
    db %11111111
    db %11111111

每個像素使用2bits表示(上下bit)，因此，一個8x8的CHR需要複製16Bytes

完成

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