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541
|
; 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:: ; 283
push af
push bc
push de
push hl
; get vblank type
ld a, [$ff9e]
and $7
; get fn pointer
ld e, a
ld d, $0
ld hl, .VBlanks
add hl, de
add hl, de
ld a, [hli]
ld h, [hl]
ld l, a
; down to business
call _hl_
; since this is called once per frame
call GameTimer
pop hl
pop de
pop bc
pop af
reti
; 2a1
.VBlanks ; 2a1
dw VBlank0 ; 0
dw VBlank1 ; 1
dw VBlank2 ; 2
dw VBlank3 ; 3
dw VBlank4 ; 4
dw VBlank5 ; 5
dw VBlank6 ; 6
dw VBlank0 ; 7
; 2b1
VBlank0:: ; 2b1
; normal operation
; rng
; scx, scy, wy, wx
; bg map buffer
; palettes
; dma transfer
; bg map
; tiles
; oam
; joypad
; sound
; inc frame counter
ld hl, $ff9b
inc [hl]
; advance rng
ld a, [rDIV]
ld b, a
ld a, [hRandomAdd]
adc b
ld [hRandomAdd], a
ld a, [rDIV]
ld b, a
ld a, [hRandomSub]
sbc b
ld [hRandomSub], a
; save bank
ld a, [hROMBank] ; current bank
ld [$ff8a], a
; scroll x
ld a, [hSCX]
ld [rSCX], a
; scroll y
ld a, [hSCY]
ld [rSCY], a
; window y
ld a, [hWY]
ld [rWY], a
; window x + 7
ld a, [hWX]
ld [rWX], a
; some time management is in order
; only have time for one of these during vblank
; bg map buffer has priority
call UpdateBGMapBuffer
jr c, .doneframeaction
; then pals
call UpdatePalsIfCGB
jr c, .doneframeaction
; dma transfer
call DMATransfer
jr c, .doneframeaction
; bg map
call UpdateBGMap
; these have their own timing checks
call Serve2bppRequest
call Serve1bppRequest
call AnimateTileset
.doneframeaction
; oam update off?
ld a, [hOAMUpdate]
and a
jr nz, .vblankoccurred
; update oam by dma transfer
call hPushOAM
; @PushOAM:
; ld a, Sprites >> 8
; ld [rDMA], a
; ld a, $28
; .loop
; dec a
; jr nz, .loop
; ret
; vblank-sensitive operations are done
.vblankoccurred
; tell other fns vblank happened
xor a
ld [VBlankOccurred], a
; dec OverworldDelay until 0
ld a, [OverworldDelay]
and a
jr z, .textdelay
dec a
ld [OverworldDelay], a
.textdelay
; dec text delay counter until 0
ld a, [TextDelayFrames]
and a
jr z, .joypad
dec a
ld [TextDelayFrames], a
.joypad
call Joypad
; update sound
ld a, BANK(_UpdateSound)
rst Bankswitch ; bankswitch
call _UpdateSound
ld a, [$ff8a]
rst Bankswitch ; restore bank
;
ld a, [hSeconds]
ld [$ffe3], a
ret
; 325
VBlank2:: ; 325
; sound only
; save bank
ld a, [hROMBank]
ld [$ff8a], a
; update sound
ld a, BANK(_UpdateSound)
rst Bankswitch ; bankswitch
call _UpdateSound
; restore bank
ld a, [$ff8a]
rst Bankswitch
; tell other fns vblank happened
xor a
ld [VBlankOccurred], a
ret
; 337
VBlank1:: ; 337
; scx, scy
; palettes
; bg map
; tiles
; oam
; sound / lcd stat
; save bank
ld a, [hROMBank]
ld [$ff8a], a
; scroll x
ld a, [hSCX]
ld [rSCX], a
; scroll y
ld a, [hSCY]
ld [rSCY], a
; time-sensitive fns
call UpdatePals
jr c, .vblankoccurred
; these have their own timing checks
call UpdateBGMap
call Serve2bppRequest@VBlank
; update oam by dma transfer
call hPushOAM
; @PushOAM:
; ld a, Sprites >> 8
; ld [rDMA], a
; ld a, $28
; .loop
; dec a
; jr nz, .loop
; ret
.vblankoccurred
; tell other fns vblank happened
xor a
ld [VBlankOccurred], a
; get requested ints
ld a, [rIF]
ld b, a
; discard requested ints
xor a
ld [rIF], a
; enable lcd stat
ld a, %10 ; lcd stat
ld [rIE], a
; rerequest serial int if applicable (still disabled)
; request lcd stat
ld a, b
and %1000 ; serial
or %10 ; lcd stat
ld [rIF], a
ei
; update sound
ld a, BANK(_UpdateSound)
rst Bankswitch ; bankswitch
call _UpdateSound
; restore bank
ld a, [$ff8a]
rst Bankswitch
di
; get requested ints
ld a, [rIF]
ld b, a
; discard requested ints
xor a
ld [rIF], a
; enable ints besides joypad
ld a, %1111 ; serial timer lcdstat vblank
ld [rIE], a
; rerequest ints
ld a, b
ld [rIF], a
ret
; 37f
UpdatePals:: ; 37f
; update pals for either dmg or cgb
; check cgb
ld a, [hCGB]
and a
jp nz, UpdateCGBPals
; update gb pals
ld a, [$cfc7]
ld [rBGP], a
ld a, [$cfc8]
ld [rOBP0], a
ld a, [$cfc9]
ld [rOBP1], a
and a
ret
; 396
VBlank3:: ; 396
; scx, scy
; palettes
; bg map
; tiles
; oam
; sound / lcd stat
; save bank
ld a, [hROMBank]
ld [$ff8a], a
; scroll x
ld a, [hSCX]
ld [rSCX], a
; scroll y
ld a, [hSCY]
ld [rSCY], a
; any pals to update?
ld a, [hCGBPalUpdate]
and a
call nz, ForceUpdateCGBPals
jr c, .vblankoccurred
; else
call UpdateBGMap
call Serve2bppRequest@VBlank
; update oam by dma transfer
call hPushOAM
; @PushOAM:
; ld a, Sprites >> 8
; ld [rDMA], a
; ld a, $28
; .loop
; dec a
; jr nz, .loop
; ret
.vblankoccurred
; tell other fns vblank happened
xor a
ld [VBlankOccurred], a
; save int flag
ld a, [rIF]
push af
; reset ints
xor a
ld [rIF], a
; force lcdstat int during sound update
ld a, %10 ; lcd stat
ld [rIE], a
ld [rIF], a
ei
; update sound
ld a, BANK(_UpdateSound)
rst Bankswitch ; bankswitch
call _UpdateSound
; restore bank
ld a, [$ff8a]
rst Bankswitch
di
; request lcdstat
ld a, [rIF]
ld b, a
; and any other ints
pop af
or b
ld b, a
; reset ints
xor a
ld [rIF], a
; enable ints besides joypad
ld a, %1111 ; serial timer lcdstat vblank
ld [rIE], a
; request ints
ld a, b
ld [rIF], a
ret
; 3df
VBlank4:: ; 3df
; bg map
; tiles
; oam
; joypad
; serial
; sound
; save bank
ld a, [hROMBank]
ld [$ff8a], a
call UpdateBGMap
call Serve2bppRequest
; update oam by dma transfer
call hPushOAM
; @PushOAM:
; ld a, Sprites >> 8
; ld [rDMA], a
; ld a, $28
; .loop
; dec a
; jr nz, .loop
; ret
; update joypad
call Joypad
; tell other fns vblank happened
xor a
ld [VBlankOccurred], a
; handshake
call AskSerial
; update sound
ld a, BANK(_UpdateSound)
rst Bankswitch ; bankswitch
call _UpdateSound
; restore bank
ld a, [$ff8a]
rst Bankswitch
ret
; 400
VBlank5:: ; 400
; scx
; palettes
; bg map
; tiles
; joypad
;
; save bank
ld a, [hROMBank]
ld [$ff8a], a
; scroll x
ld a, [hSCX]
ld [rSCX], a
; if we can update pals, skip this part
call UpdatePalsIfCGB
jr c, .vblankoccurred
call UpdateBGMap
call Serve2bppRequest
.vblankoccurred
; tell other fns vblank happened
xor a
ld [VBlankOccurred], a
; joypad
call Joypad
; discard requested ints
xor a
ld [rIF], a
; enable lcd stat
ld a, %10 ; lcd stat
ld [rIE], a
; request lcd stat
ld [rIF], a
ei
; update sound
ld a, BANK(_UpdateSound)
rst Bankswitch ; bankswitch
call _UpdateSound
; restore bank
ld a, [$ff8a]
rst Bankswitch
di
; discard requested ints
xor a
ld [rIF], a
; enable ints besides joypad
ld a, %1111 ; serial timer lcdstat vblank
ld [rIE], a
ret
; 436
VBlank6:: ; 436
; palettes
; tiles
; dma transfer
; sound
; save bank
ld a, [hROMBank]
ld [$ff8a], a
; inc frame counter
ld hl, $ff9b
inc [hl]
call UpdateCGBPals
jr c, .vblankoccurred
call Serve2bppRequest
call Serve1bppRequest
call DMATransfer
.vblankoccurred
; tell other fns vblank happened
xor a
ld [VBlankOccurred], a
; update sound
ld a, BANK(_UpdateSound)
rst Bankswitch ; bankswitch
call _UpdateSound
; restore bank
ld a, [$ff8a]
rst Bankswitch
ret
; 45a
|
