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INCLUDE "constants.asm"
SECTION "home/vblank.asm", ROM0
VBlank::
push af
push bc
push de
push hl
ldh a, [hVBlank]
and 3
ld e, a
ld d, 0
ld hl, .blanks
add hl, de
add hl, de
ld a, [hli]
ld h, [hl]
ld l, a
ld de, .return
push de
jp hl
.return
pop hl
pop de
pop bc
pop af
reti
.blanks
dw VBlank0
dw VBlank1
dw VBlank2
dw VBlank3
VBlank0::
; rng
; scx, scy, wy, wx
; bg map
; row/column redraw
; copy 2bpp
; copy 1bpp
; animate tileset
; copy far 2bpp
; enable oam sprites
; oam
; joypad
; sound / serial / lcd_stat
ldh a, [hVBlankCounter]
inc a
ldh [hVBlankCounter], a
bit 0, a
jr nz, .even_frame
ldh a, [hRTCRandom]
ld b, a
ldh a, [rLY]
adc b
.even_frame
; advance random variables
ld b, a
ldh a, [hRandomAdd]
adc b
ldh [hRandomAdd], a
ld b, a
ldh a, [hRandomSub]
sbc b
ldh [hRandomSub], a
ldh a, [hRTCSeconds]
ldh [hRTCRandom], a
ldh a, [hROMBank]
ld [wVBlankSavedROMBank], a
ldh a, [hSCX]
ldh [rSCX], a
ldh a, [hSCY]
ldh [rSCY], a
ld a, [wDisableVBlankWYUpdate]
and a
jr nz, .ok
ldh a, [hWY]
ldh [rWY], a
ldh a, [hWX]
ldh [rWX], a
.ok
call AutoBgMapTransfer
call RedrawRowOrColumn
call VBlankCopy
call VBlankCopyDouble
call AnimateTileset
call VBlankCopyFar
call EnableSprites
call hOAMDMA
xor a
ld [wVBlankOccurred], a
ld a, [wVBlankJoyFrameCounter]
and a
jr z, .skipDec
dec a
ld [wVBlankJoyFrameCounter], a
.skipDec
call Joypad
xor a
ldh [rIF], a
ld a, (1 << SERIAL | 1 << LCD_STAT)
ldh [rIE], a
ld a, (1 << LCD_STAT)
ldh [rIF], a
ei
call UpdateSound
ld a, [wVBlankSavedROMBank]
call Bankswitch
di
xor a
ldh [rIF], a
ld a, (1 << JOYPAD | 1 << SERIAL | 1 << TIMER | 1 << LCD_STAT | 1 << VBLANK)
ldh [rIE], a
ret
VBlank1::
; Simple VBlank
;
; scx, scy
; dmg pals
; bg map
; copy 2bpp
; oam
; sound / lcd_stat
; no counters!
ldh a, [hROMBank]
ld [wVBlankSavedROMBank], a
ldh a, [hSCX]
ldh [rSCX], a
ldh a, [hSCY]
ldh [rSCY], a
ld a, [wBGP]
ldh [rBGP], a
ld a, [wOBP0]
ldh [rOBP0], a
ld a, [wOBP1]
ldh [rOBP1], a
call AutoBgMapTransfer
call VBlankCopy
ld a, [wDisableVBlankOAMUpdate]
and a
jr nz, .skip_oam
call hOAMDMA
.skip_oam
xor a
ld [wVBlankOccurred], a
xor a
ldh [rIF], a
ld a, (1 << LCD_STAT)
ldh [rIE], a
ldh [rIF], a
ei
call UpdateSound
ld a, [wVBlankSavedROMBank]
call Bankswitch
di
xor a
ldh [rIF], a
ld a, (1 << JOYPAD | 1 << SERIAL | 1 << TIMER | 1 << LCD_STAT | 1 << VBLANK)
ldh [rIE], a
ret
VBlank2::
; rng
; scx, scy, wy, wx
; joypad
; bg map
; row/column redraw
; copy 2bpp
; copy 1bpp
; copy far 2bpp
; oam
; sound
ldh a, [hVBlankCounter]
inc a
ldh [hVBlankCounter], a
bit 0, a
jr nz, .even_frame
ldh a, [rLY]
.even_frame
; advance random variables
ld b, a
ldh a, [hRandomAdd]
adc b
ldh [hRandomAdd], a
ld b, a
ldh a, [hRandomSub]
sbc b
ldh [hRandomSub], a
call Joypad
ldh a, [hROMBank]
ld [wVBlankSavedROMBank], a
ldh a, [hSCX]
ldh [rSCX], a
ldh a, [hSCY]
ldh [rSCY], a
ld a, [wDisableVBlankWYUpdate]
and a
jr nz, .ok
ldh a, [hWY]
ldh [rWY], a
ldh a, [hWX]
ldh [rWX], a
.ok
call AutoBgMapTransfer
call RedrawRowOrColumn
call VBlankCopy
call VBlankCopyDouble
call VBlankCopyFar
call hOAMDMA
xor a
ld [wVBlankOccurred], a
ld a, [wVBlankJoyFrameCounter]
and a
jr z, .skipDec
dec a
ld [wVBlankJoyFrameCounter], a
.skipDec
call UpdateSound
ld a, [wVBlankSavedROMBank]
call Bankswitch
ret
VBlank3::
; rng
; joypad
; scx, scy, wy, wx
; bg map
; row/column redraw
; copy 2bpp
; copy 1bpp
; animate tileset
; copy far 2bpp
; enable oam sprites
; oam
; sound / lcd_stat
ldh a, [hVBlankCounter]
inc a
ldh [hVBlankCounter], a
bit 0, a
jr nz, .even_frame
ldh a, [rLY]
.even_frame
ld b, a
ldh a, [hRandomAdd]
adc b
ldh [hRandomAdd], a
ld b, a
ldh a, [hRandomSub]
sbc b
ldh [hRandomSub], a
call Joypad
ldh a, [hROMBank]
ld [wVBlankSavedROMBank], a
ldh a, [hSCX]
ldh [rSCX], a
ldh a, [hSCY]
ldh [rSCY], a
ld a, [wDisableVBlankWYUpdate]
and a
jr nz, .ok
ldh a, [hWY]
ldh [rWY], a
ldh a, [hWX]
ldh [rWX], a
.ok
call AutoBgMapTransfer
call RedrawRowOrColumn
call VBlankCopy
call VBlankCopyDouble
call AnimateTileset
call VBlankCopyFar
call EnableSprites
call hOAMDMA
xor a
ld [wVBlankOccurred], a
ld a, [wVBlankJoyFrameCounter]
and a
jr z, .skipDec
dec a
ld [wVBlankJoyFrameCounter], a
.skipDec
xor a
ldh [rIF], a
ld a, (1 << LCD_STAT)
ldh [rIE], a
ldh [rIF], a
ei
call UpdateSound
ld a, [wVBlankSavedROMBank]
call Bankswitch
di
xor a
ldh [rIF], a
ld a, (1 << JOYPAD | 1 << SERIAL | 1 << TIMER | 1 << LCD_STAT | 1 << VBLANK)
ldh [rIE], a
ret
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