1 files changed, 105 insertions, 0 deletions
diff --git a/home/vblank.asm b/home/vblank.asm
new file mode 100644
index 00000000..15f91437
--- /dev/null
+++ b/home/vblank.asm
@@ -0,0 +1,105 @@
+VBlank::
+
+	push af
+	push bc
+	push de
+	push hl
+
+	ld a, [H_LOADEDROMBANK]
+	ld [wd122], a
+
+	ld a, [$ffae]
+	ld [rSCX], a
+	ld a, [$ffaf]
+	ld [rSCY], a
+
+	ld a, [wd0a0]
+	and a
+	jr nz, .ok
+	ld a, [$ffb0]
+	ld [rWY], a
+.ok
+
+	call AutoBgMapTransfer
+	call VBlankCopyBgMap
+	call RedrawExposedScreenEdge
+	call VBlankCopy
+	call VBlankCopyDouble
+	call UpdateMovingBgTiles
+	call $ff80 ; hOAMDMA
+	ld a, Bank(PrepareOAMData)
+	ld [H_LOADEDROMBANK], a
+	ld [MBC3RomBank], a
+	call PrepareOAMData
+
+	; VBlank-sensitive operations end.
+
+	call Random
+
+	ld a, [H_VBLANKOCCURRED]
+	and a
+	jr z, .vblanked
+	xor a
+	ld [H_VBLANKOCCURRED], a
+.vblanked
+
+	ld a, [H_FRAMECOUNTER]
+	and a
+	jr z, .decced
+	dec a
+	ld [H_FRAMECOUNTER], a
+.decced
+
+	call Func_28cb
+
+	ld a, [wc0ef] ; music ROM bank
+	ld [H_LOADEDROMBANK], a
+	ld [MBC3RomBank], a
+
+	cp BANK(Music2_UpdateMusic)
+	jr nz, .notbank2
+.bank2
+	call Music2_UpdateMusic
+	jr .afterMusic
+.notbank2
+	cp BANK(Music8_UpdateMusic)
+	jr nz, .bank1F
+.bank8
+	call Func_2136e
+	call Music8_UpdateMusic
+	jr .afterMusic
+.bank1F
+	call Music1f_UpdateMusic
+.afterMusic
+
+	callba Func_18dee ; keep track of time played
+
+	ld a, [$fff9]
+	and a
+	call z, ReadJoypad
+
+	ld a, [wd122]
+	ld [H_LOADEDROMBANK], a
+	ld [MBC3RomBank], a
+
+	pop hl
+	pop de
+	pop bc
+	pop af
+	reti
+
+
+DelayFrame::
+; Wait for the next vblank interrupt.
+; As a bonus, this saves battery.
+
+NOT_VBLANKED EQU 1
+
+	ld a, NOT_VBLANKED
+	ld [H_VBLANKOCCURRED], a
+.halt
+	halt
+	ld a, [H_VBLANKOCCURRED]
+	and a
+	jr nz, .halt
+	ret