掌機 - Game Boy - Assembly - Palette

參考資訊：
https://bgb.bircd.org/
https://github.com/gbdev/rgbds
https://github.com/sinamas/gambatte
https://github.com/lancekindle/DMGreport

Game Boy支援4種色階並且有3個調色盤(1個Background、2個Object)可以使用，顏色的色階則是由CHR像素資料控制，色階對應的顏色則可以由調色盤控制


main.s

BGP         equ $ff47
OBP0        equ $ff48
OBP1        equ $ff49
LCDC        equ $ff40
LCDCF_OBJ8  equ %00000000
LCDCF_OBJON equ %00000010
LCDCF_ON    equ %10000000
IE          equ $ffff
IEF_VBLANK  equ %00000001
STAT        equ $ff41
STATF_BUSY  equ %00000010

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]
    and ~LCDCF_ON
    ld [LCDC], a

    ld d, 32
    ld bc, tile
    ld hl, $8000
copy_tile:
    ld a, [bc]
    ld [hl+], a
    inc bc
    dec d
    jr nz, copy_tile

    ld hl, $9800
    ld [hl], 1

    ld a, %11100100
    ld [BGP], a

    ld a, [LCDC]
    or LCDCF_ON
    ld [LCDC], a

    jp @

tile:
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %00000000

    db %00000000
    db %00000000
    db %00000000
    db %00000000
    db %11111111
    db %00000000
    db %11111111
    db %00000000
    db %00000000
    db %11111111
    db %00000000
    db %11111111
    db %11111111
    db %11111111
    db %11111111
    db %11111111

每個像素的色階由tile設定，因此，顯示一個8x8 Pixels，需要16 Bytes(1個Pixel由2個bits控制)，色階對應的顏色則由BGP(Background)、OBP0(Object)、OBP1(Object)設定

完成