Game Boy >> Assembly

VBLANK

---

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

暫存器



main.s

SCX        equ $ff43
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

loop:
    halt

    ld a, [SCX]
    inc a
    ld [SCX], a
 
    jp loop

執行halt指令後，CPU進入省電模式，待VBLANK中斷發生後，才繼續往下執行，每發一次VBLANK中斷，移動x捲軸一次

完成

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