First Commit

Upload literally everything from the pokecrystal16 expand-move-ID branch

home/vblank.asm

@@ -0,0 +1,421 @@
+; VBlank is the interrupt responsible for updating VRAM.
+
+; In Pokemon Crystal, VBlank has been hijacked to act as the
+; main loop. After time-sensitive graphics operations have been
+; performed, joypad input and sound functions are executed.
+
+; This prevents the display and audio output from lagging.
+
+VBlank::
+	push af
+	push bc
+	push de
+	push hl
+
+	ldh a, [hVBlank]
+	and 7
+
+	ld e, a
+	ld d, 0
+	ld hl, .VBlanks
+	add hl, de
+	add hl, de
+	ld a, [hli]
+	ld h, [hl]
+	ld l, a
+
+	call _hl_
+
+	call GameTimer
+
+	pop hl
+	pop de
+	pop bc
+	pop af
+	reti
+
+.VBlanks:
+	dw VBlank0
+	dw VBlank1
+	dw VBlank2
+	dw VBlank3
+	dw VBlank4
+	dw VBlank5
+	dw VBlank6
+	dw VBlank0 ; just in case
+
+VBlank0::
+; normal operation
+
+; rng
+; scx, scy, wy, wx
+; bg map buffer
+; palettes
+; dma transfer
+; bg map
+; tiles
+; oam
+; joypad
+; sound
+
+	; inc frame counter
+	ld hl, hVBlankCounter
+	inc [hl]
+
+	; advance random variables
+	ldh a, [rDIV]
+	ld b, a
+	ldh a, [hRandomAdd]
+	adc b
+	ldh [hRandomAdd], a
+
+	ldh a, [rDIV]
+	ld b, a
+	ldh a, [hRandomSub]
+	sbc b
+	ldh [hRandomSub], a
+
+	ldh a, [hROMBank]
+	ldh [hROMBankBackup], a
+
+	ldh a, [hSCX]
+	ldh [rSCX], a
+	ldh a, [hSCY]
+	ldh [rSCY], a
+	ldh a, [hWY]
+	ldh [rWY], a
+	ldh a, [hWX]
+	ldh [rWX], a
+
+	; There's only time to call one of these in one vblank.
+	; Calls are in order of priority.
+
+	call UpdateBGMapBuffer
+	jr c, .done
+	call UpdatePalsIfCGB
+	jr c, .done
+	call DMATransfer
+	jr c, .done
+	call UpdateBGMap
+
+	; These have their own timing checks.
+
+	call Serve2bppRequest
+	call Serve1bppRequest
+	call AnimateTileset
+
+.done
+
+	ldh a, [hOAMUpdate]
+	and a
+	jr nz, .done_oam
+	call hTransferShadowOAM
+.done_oam
+
+	; vblank-sensitive operations are done
+
+	xor a
+	ld [wVBlankOccurred], a
+
+	ld a, [wOverworldDelay]
+	and a
+	jr z, .ok
+	dec a
+	ld [wOverworldDelay], a
+.ok
+
+	ld a, [wTextDelayFrames]
+	and a
+	jr z, .ok2
+	dec a
+	ld [wTextDelayFrames], a
+.ok2
+
+	call UpdateJoypad
+
+	ld a, BANK(_UpdateSound)
+	rst Bankswitch
+	call _UpdateSound
+	ldh a, [hROMBankBackup]
+	rst Bankswitch
+
+	ldh a, [hSeconds]
+	ldh [hUnusedBackup], a
+
+	ret
+
+VBlank2::
+; sound only
+
+	ldh a, [hROMBank]
+	ldh [hROMBankBackup], a
+
+	ld a, BANK(_UpdateSound)
+	rst Bankswitch
+	call _UpdateSound
+
+	ldh a, [hROMBankBackup]
+	rst Bankswitch
+
+	xor a
+	ld [wVBlankOccurred], a
+	ret
+
+VBlank1::
+; scx, scy
+; palettes
+; bg map
+; tiles
+; oam
+; sound / lcd stat
+
+	ldh a, [hROMBank]
+	ldh [hROMBankBackup], a
+
+	ldh a, [hSCX]
+	ldh [rSCX], a
+	ldh a, [hSCY]
+	ldh [rSCY], a
+
+	call UpdatePals
+	jr c, .done
+
+	call UpdateBGMap
+	call Serve2bppRequest_VBlank
+
+	call hTransferShadowOAM
+
+.done
+	xor a
+	ld [wVBlankOccurred], a
+
+	; get requested ints
+	ldh a, [rIF]
+	ld b, a
+	; discard requested ints
+	xor a
+	ldh [rIF], a
+	; enable lcd stat
+	ld a, 1 << LCD_STAT
+	ldh [rIE], a
+	; rerequest serial int if applicable (still disabled)
+	; request lcd stat
+	ld a, b
+	and 1 << SERIAL
+	or 1 << LCD_STAT
+	ldh [rIF], a
+
+	ei
+	ld a, BANK(_UpdateSound)
+	rst Bankswitch
+	call _UpdateSound
+	ldh a, [hROMBankBackup]
+	rst Bankswitch
+	di
+
+	; get requested ints
+	ldh a, [rIF]
+	ld b, a
+	; discard requested ints
+	xor a
+	ldh [rIF], a
+	; enable ints besides joypad
+	ld a, IE_DEFAULT
+	ldh [rIE], a
+	; rerequest ints
+	ld a, b
+	ldh [rIF], a
+	ret
+
+UpdatePals::
+; update pals for either dmg or cgb
+
+	ldh a, [hCGB]
+	and a
+	jp nz, UpdateCGBPals
+
+	; update gb pals
+	ld a, [wBGP]
+	ldh [rBGP], a
+	ld a, [wOBP0]
+	ldh [rOBP0], a
+	ld a, [wOBP1]
+	ldh [rOBP1], a
+
+	and a
+	ret
+
+VBlank3::
+; scx, scy
+; palettes
+; bg map
+; tiles
+; oam
+; sound / lcd stat
+
+	ldh a, [hROMBank]
+	ldh [hROMBankBackup], a
+
+	ldh a, [hSCX]
+	ldh [rSCX], a
+	ldh a, [hSCY]
+	ldh [rSCY], a
+
+	ldh a, [hCGBPalUpdate]
+	and a
+	call nz, ForceUpdateCGBPals
+	jr c, .done
+
+	call UpdateBGMap
+	call Serve2bppRequest_VBlank
+
+	call hTransferShadowOAM
+.done
+
+	xor a
+	ld [wVBlankOccurred], a
+
+	ldh a, [rIF]
+	push af
+	xor a
+	ldh [rIF], a
+	ld a, 1 << LCD_STAT
+	ldh [rIE], a
+	ldh [rIF], a
+
+	ei
+	ld a, BANK(_UpdateSound)
+	rst Bankswitch
+	call _UpdateSound
+	ldh a, [hROMBankBackup]
+	rst Bankswitch
+	di
+
+	; request lcdstat
+	ldh a, [rIF]
+	ld b, a
+	; and any other ints
+	pop af
+	or b
+	ld b, a
+	; reset ints
+	xor a
+	ldh [rIF], a
+	; enable ints besides joypad
+	ld a, IE_DEFAULT
+	ldh [rIE], a
+	; request ints
+	ld a, b
+	ldh [rIF], a
+	ret
+
+VBlank4::
+; bg map
+; tiles
+; oam
+; joypad
+; serial
+; sound
+
+	ldh a, [hROMBank]
+	ldh [hROMBankBackup], a
+
+	call UpdateBGMap
+	call Serve2bppRequest
+
+	call hTransferShadowOAM
+
+	call UpdateJoypad
+
+	xor a
+	ld [wVBlankOccurred], a
+
+	call AskSerial
+
+	ld a, BANK(_UpdateSound)
+	rst Bankswitch
+	call _UpdateSound
+
+	ldh a, [hROMBankBackup]
+	rst Bankswitch
+	ret
+
+VBlank5::
+; scx
+; palettes
+; bg map
+; tiles
+; joypad
+;
+
+	ldh a, [hROMBank]
+	ldh [hROMBankBackup], a
+
+	ldh a, [hSCX]
+	ldh [rSCX], a
+
+	call UpdatePalsIfCGB
+	jr c, .done
+
+	call UpdateBGMap
+	call Serve2bppRequest
+.done
+
+	xor a
+	ld [wVBlankOccurred], a
+
+	call UpdateJoypad
+
+	xor a
+	ldh [rIF], a
+	ld a, 1 << LCD_STAT
+	ldh [rIE], a
+	; request lcd stat
+	ldh [rIF], a
+
+	ei
+	ld a, BANK(_UpdateSound)
+	rst Bankswitch
+	call _UpdateSound
+	ldh a, [hROMBankBackup]
+	rst Bankswitch
+	di
+
+	xor a
+	ldh [rIF], a
+	; enable ints besides joypad
+	ld a, IE_DEFAULT
+	ldh [rIE], a
+	ret
+
+VBlank6::
+; palettes
+; tiles
+; dma transfer
+; sound
+
+	ldh a, [hROMBank]
+	ldh [hROMBankBackup], a
+
+	; inc frame counter
+	ld hl, hVBlankCounter
+	inc [hl]
+
+	call UpdateCGBPals
+	jr c, .done
+
+	call Serve2bppRequest
+	call Serve1bppRequest
+	call DMATransfer
+.done
+
+	xor a
+	ld [wVBlankOccurred], a
+
+	ld a, BANK(_UpdateSound)
+	rst Bankswitch
+	call _UpdateSound
+
+	ldh a, [hROMBankBackup]
+	rst Bankswitch
+	ret