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; initialize scroll, window, and lcdc registers, set trampoline functions
; for the lcdc and vblank interrupts, latch clock data, and enable SRAM/RTC
SetupRegisters:
xor a
ldh [rSCY], a
ldh [rSCX], a
ldh [rWY], a
ldh [rWX], a
ld [wcab0], a
ld [wcab1], a
ld [wcab2], a
ldh [hSCX], a
ldh [hSCY], a
ldh [hWX], a
ldh [hWY], a
xor a
ld [wReentrancyFlag], a
ld a, $c3 ; $c3 = jp nn
ld [wLCDCFunctionTrampoline], a
ld [wVBlankFunctionTrampoline], a
ld hl, wVBlankFunctionTrampoline + 1
ld [hl], LOW(NoOp) ;
inc hl ; load `jp NoOp`
ld [hl], HIGH(NoOp) ;
ld a, LCDC_BGON | LCDC_OBJON | LCDC_OBJ16 | LCDC_WIN9C00
ld [wLCDC], a
ld a, $1
ld [MBC3LatchClock], a
ld a, SRAM_ENABLE
ld [MBC3SRamEnable], a
NoOp:
ret
; sets wConsole and, if CGB, selects WRAM bank 1 and switches to double speed mode
DetectConsole:
ld b, CONSOLE_CGB
cp GBC
jr z, .got_console
call DetectSGB
ld b, CONSOLE_DMG
jr nc, .got_console
call InitSGB
ld b, CONSOLE_SGB
.got_console
ld a, b
ld [wConsole], a
cp CONSOLE_CGB
ret nz
ld a, $01
ldh [rSVBK], a
call SwitchToCGBDoubleSpeed
ret
; initialize the palettes (both monochrome and color)
SetupPalettes:
ld hl, wBGP
ld a, %11100100
ldh [rBGP], a
ld [hli], a ; wBGP
ldh [rOBP0], a
ldh [rOBP1], a
ld [hli], a ; wOBP0
ld [hl], a ; wOBP1
xor a
ld [wFlushPaletteFlags], a
ld a, [wConsole]
cp CONSOLE_CGB
ret nz
ld de, wBackgroundPalettesCGB
ld c, 16
.copy_pals_loop
ld hl, InitialPalette
ld b, CGB_PAL_SIZE
.copy_bytes_loop
ld a, [hli]
ld [de], a
inc de
dec b
jr nz, .copy_bytes_loop
dec c
jr nz, .copy_pals_loop
call FlushAllCGBPalettes
ret
InitialPalette:
rgb 28, 28, 24
rgb 21, 21, 16
rgb 10, 10, 08
rgb 00, 00, 00
; clear VRAM tile data ([wTileMapFill] should be an empty tile)
SetupVRAM:
call FillTileMap
call CheckForCGB
jr c, .vram0
call BankswitchVRAM1
call .vram0
call BankswitchVRAM0
.vram0
ld hl, v0Tiles0
ld bc, v0BGMap0 - v0Tiles0
.loop
xor a
ld [hli], a
dec bc
ld a, b
or c
jr nz, .loop
ret
; fill VRAM0 BG map 0 with [wTileMapFill] and VRAM1 BG map 0 with $00
FillTileMap:
call BankswitchVRAM0
ld hl, v0BGMap0
ld bc, v0BGMap1 - v0BGMap0
.vram0_loop
ld a, [wTileMapFill]
ld [hli], a
dec bc
ld a, c
or b
jr nz, .vram0_loop
ld a, [wConsole]
cp CONSOLE_CGB
ret nz
call BankswitchVRAM1
ld hl, v1BGMap0
ld bc, v1BGMap1 - v1BGMap0
.vram1_loop
xor a
ld [hli], a
dec bc
ld a, c
or b
jr nz, .vram1_loop
call BankswitchVRAM0
ret
; zero work RAM, stack area, and high RAM ($C000-$DFFF, $FF80-$FFEF)
ZeroRAM:
ld hl, $c000
ld bc, $e000 - $c000
.zero_wram_loop
xor a
ld [hli], a
dec bc
ld a, c
or b
jr nz, .zero_wram_loop
ld c, LOW($ff80)
ld b, $fff0 - $ff80
xor a
.zero_hram_loop
ld [$ff00+c], a
inc c
dec b
jr nz, .zero_hram_loop
ret
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