SameBoy/BootROMs/cgb_boot_fast.asm

785 lines
14 KiB
NASM

; Sameboy CGB bootstrap ROM
; Todo: use friendly names for HW registers instead of magic numbers
; Todo: add support for games that assume DMG boot logo (Such as X), like the
; original boot ROM.
SECTION "BootCode", ROM0[$0]
Start:
; Init stack pointer
ld sp, $fffe
; Select RAM bank
ld a, 2
ldh [$70], a
xor a
; Clear memory VRAM
ld hl, $8000
call ClearMemoryPage
ld h, $d0
call ClearMemoryPage
; Clear OAM
ld hl, $fe00
ld c, $a0
xor a
.clearOAMLoop
ldi [hl], a
dec c
jr nz, .clearOAMLoop
; Init Audio
ld a, $80
ldh [$26], a
ldh [$11], a
ld a, $f3
ldh [$12], a
ldh [$25], a
ld a, $77
ldh [$24], a
ld hl, $FF30
; Init waveform
xor a
ld c, $10
.waveformLoop
ldi [hl], a
cpl
dec c
jr nz, .waveformLoop
; Init BG palette
ld a, $fc
ldh [$47], a
; Load logo from ROM.
; A nibble represents a 4-pixels line, 2 bytes represent a 4x4 tile, scaled to 8x8.
; Tiles are ordered left to right, top to bottom.
; These tiles are not used, but are required for DMG compatibility. This is done
; by the original CGB Boot ROM as well.
ld de, $104 ; Logo start
ld hl, $8010 ; This is where we load the tiles in VRAM
.loadLogoLoop
ld a, [de] ; Read 2 rows
ld b, a
call DoubleBitsAndWriteRow
call DoubleBitsAndWriteRow
inc de
ld a, e
xor $34 ; End of logo
jr nz, .loadLogoLoop
call ReadTrademarkSymbol
; Clear the second VRAM bank
ld a, 1
ldh [$4F], a
xor a
ld hl, $8000
call ClearMemoryPage
; Copy (unresized) ROM logo
ld de, $104
ld c, 6
.CGBROMLogoLoop
push bc
call ReadCGBLogoTile
pop bc
dec c
jr nz, .CGBROMLogoLoop
inc hl
call ReadTrademarkSymbol
; Load Tilemap
ld hl, $98C2
ld b, 3
ld a, 8
.tilemapLoop
ld c, $10
.tilemapRowLoop
ld [hl], a
push af
; Switch to second VRAM Bank
ld a, 1
ldh [$4F], a
ld a, 8
ld [hl], a
; Switch to back first VRAM Bank
xor a
ldh [$4F], a
pop af
ldi [hl], a
inc a
dec c
jr nz, .tilemapRowLoop
ld de, $10
add hl, de
dec b
jr nz, .tilemapLoop
cp $38
jr nz, .doneTilemap
ld hl, $99a7
ld b, 1
ld c, 7
jr .tilemapRowLoop
.doneTilemap
; Clear Palettes
ld c, 64
ld hl, BgPalettes
ld a, $FF
.clearPalettesLoop:
ldi [hl], a
dec c
jr nz, .clearPalettesLoop
ld hl, BgPalettes
ld d, 64 ; Length of write
ld e, 0 ; Index of write
call LoadBGPalettes
; Turn on LCD
ld a, $91
ldh [$40], a
call Preboot
; Will be filled with NOPs
SECTION "BootGame", ROM0[$fe]
BootGame:
ldh [$50], a
SECTION "MoreStuff", ROM0[$200]
; Game Palettes Data
TitleChecksums:
db $00 ; Default
db $88 ; ALLEY WAY
db $16 ; YAKUMAN
db $36 ; BASEBALL, (Game and Watch 2)
db $D1 ; TENNIS
db $DB ; TETRIS
db $F2 ; QIX
db $3C ; DR.MARIO
db $8C ; RADARMISSION
db $92 ; F1RACE
db $3D ; YOSSY NO TAMAGO
db $5C ;
db $58 ; X
db $C9 ; MARIOLAND2
db $3E ; YOSSY NO COOKIE
db $70 ; ZELDA
db $1D ;
db $59 ;
db $69 ; TETRIS FLASH
db $19 ; DONKEY KONG
db $35 ; MARIO'S PICROSS
db $A8 ;
db $14 ; POKEMON RED, (GAMEBOYCAMERA G)
db $AA ; POKEMON GREEN
db $75 ; PICROSS 2
db $95 ; YOSSY NO PANEPON
db $99 ; KIRAKIRA KIDS
db $34 ; GAMEBOY GALLERY
db $6F ; POCKETCAMERA
db $15 ;
db $FF ; BALLOON KID
db $97 ; KINGOFTHEZOO
db $4B ; DMG FOOTBALL
db $90 ; WORLD CUP
db $17 ; OTHELLO
db $10 ; SUPER RC PRO-AM
db $39 ; DYNABLASTER
db $F7 ; BOY AND BLOB GB2
db $F6 ; MEGAMAN
db $A2 ; STAR WARS-NOA
db $49 ;
db $4E ; WAVERACE
db $43 | $80 ;
db $68 ; LOLO2
db $E0 ; YOSHI'S COOKIE
db $8B ; MYSTIC QUEST
db $F0 ;
db $CE ; TOPRANKINGTENNIS
db $0C ; MANSELL
db $29 ; MEGAMAN3
db $E8 ; SPACE INVADERS
db $B7 ; GAME&WATCH
db $86 ; DONKEYKONGLAND95
db $9A ; ASTEROIDS/MISCMD
db $52 ; STREET FIGHTER 2
db $01 ; DEFENDER/JOUST
db $9D ; KILLERINSTINCT95
db $71 ; TETRIS BLAST
db $9C ; PINOCCHIO
db $BD ;
db $5D ; BA.TOSHINDEN
db $6D ; NETTOU KOF 95
db $67 ;
db $3F ; TETRIS PLUS
db $6B ; DONKEYKONGLAND 3
; For these games, the 4th letter is taken into account
FirstChecksumWithDuplicate:
; Let's play hangman!
db $B3 ; ???[B]????????
db $46 ; SUP[E]R MARIOLAND
db $28 ; GOL[F]
db $A5 ; SOL[A]RSTRIKER
db $C6 ; GBW[A]RS
db $D3 ; KAE[R]UNOTAMENI
db $27 ; ???[B]????????
db $61 ; POK[E]MON BLUE
db $18 ; DON[K]EYKONGLAND
db $66 ; GAM[E]BOY GALLERY2
db $6A ; DON[K]EYKONGLAND 2
db $BF ; KID[ ]ICARUS
db $0D ; TET[R]IS2
db $F4 ; ???[-]????????
db $B3 ; MOG[U]RANYA
db $46 ; ???[R]????????
db $28 ; GAL[A]GA&GALAXIAN
db $A5 ; BT2[R]AGNAROKWORLD
db $C6 ; KEN[ ]GRIFFEY JR
db $D3 ; ???[I]????????
db $27 ; MAG[N]ETIC SOCCER
db $61 ; VEG[A]S STAKES
db $18 ; ???[I]????????
db $66 ; MIL[L]I/CENTI/PEDE
db $6A ; MAR[I]O & YOSHI
db $BF ; SOC[C]ER
db $0D ; POK[E]BOM
db $F4 ; G&W[ ]GALLERY
db $B3 ; TET[R]IS ATTACK
ChecksumsEnd:
PalettePerChecksum:
; | $80 means game requires DMG boot tilemap
db 0 ; Default Palette
db 4 ; ALLEY WAY
db 5 ; YAKUMAN
db 35 ; BASEBALL, (Game and Watch 2)
db 34 ; TENNIS
db 3 ; TETRIS
db 31 ; QIX
db 15 ; DR.MARIO
db 10 ; RADARMISSION
db 5 ; F1RACE
db 19 ; YOSSY NO TAMAGO
db 36 ;
db 7 | $80 ; X
db 37 ; MARIOLAND2
db 30 ; YOSSY NO COOKIE
db 44 ; ZELDA
db 21 ;
db 32 ;
db 31 ; TETRIS FLASH
db 20 ; DONKEY KONG
db 5 ; MARIO'S PICROSS
db 33 ;
db 13 ; POKEMON RED, (GAMEBOYCAMERA G)
db 14 ; POKEMON GREEN
db 5 ; PICROSS 2
db 29 ; YOSSY NO PANEPON
db 5 ; KIRAKIRA KIDS
db 18 ; GAMEBOY GALLERY
db 9 ; POCKETCAMERA
db 3 ;
db 2 ; BALLOON KID
db 26 ; KINGOFTHEZOO
db 25 ; DMG FOOTBALL
db 25 ; WORLD CUP
db 41 ; OTHELLO
db 42 ; SUPER RC PRO-AM
db 26 ; DYNABLASTER
db 45 ; BOY AND BLOB GB2
db 42 ; MEGAMAN
db 45 ; STAR WARS-NOA
db 36 ;
db 38 ; WAVERACE
db 26 ;
db 42 ; LOLO2
db 30 ; YOSHI'S COOKIE
db 41 ; MYSTIC QUEST
db 34 ;
db 34 ; TOPRANKINGTENNIS
db 5 ; MANSELL
db 42 ; MEGAMAN3
db 6 ; SPACE INVADERS
db 5 ; GAME&WATCH
db 33 ; DONKEYKONGLAND95
db 25 ; ASTEROIDS/MISCMD
db 42 ; STREET FIGHTER 2
db 42 ; DEFENDER/JOUST
db 40 ; KILLERINSTINCT95
db 2 ; TETRIS BLAST
db 16 ; PINOCCHIO
db 25 ;
db 42 ; BA.TOSHINDEN
db 42 ; NETTOU KOF 95
db 5 ;
db 0 ; TETRIS PLUS
db 39 ; DONKEYKONGLAND 3
db 36 ;
db 22 ; SUPER MARIOLAND
db 25 ; GOLF
db 6 ; SOLARSTRIKER
db 32 ; GBWARS
db 12 ; KAERUNOTAMENI
db 36 ;
db 11 ; POKEMON BLUE
db 39 ; DONKEYKONGLAND
db 18 ; GAMEBOY GALLERY2
db 39 ; DONKEYKONGLAND 2
db 24 ; KID ICARUS
db 31 ; TETRIS2
db 50 ;
db 17 ; MOGURANYA
db 46 ;
db 6 ; GALAGA&GALAXIAN
db 27 ; BT2RAGNAROKWORLD
db 0 ; KEN GRIFFEY JR
db 47 ;
db 41 ; MAGNETIC SOCCER
db 41 ; VEGAS STAKES
db 0 ;
db 0 ; MILLI/CENTI/PEDE
db 19 ; MARIO & YOSHI
db 34 ; SOCCER
db 23 ; POKEBOM
db 18 ; G&W GALLERY
db 29 ; TETRIS ATTACK
Dups4thLetterArray:
db "BEFAARBEKEK R-URAR INAILICE R"
; We assume the last three arrays fit in the same $100 byte page!
PaletteCombinations:
palette_comb: MACRO ; Obj0, Obj1, Bg
db \1 * 8, \2 * 8, \3 *8
ENDM
palette_comb 4, 4, 29
palette_comb 18, 18, 18
palette_comb 20, 20, 20
palette_comb 24, 24, 24
palette_comb 9, 9, 9
palette_comb 0, 0, 0
palette_comb 27, 27, 27
palette_comb 5, 5, 5
palette_comb 12, 12, 12
palette_comb 26, 26, 26
palette_comb 16, 8, 8
palette_comb 4, 28, 28
palette_comb 4, 2, 2
palette_comb 3, 4, 4
palette_comb 4, 29, 29
palette_comb 28, 4, 28
palette_comb 2, 17, 2
palette_comb 16, 16, 8
palette_comb 4, 4, 7
palette_comb 4, 4, 18
palette_comb 4, 4, 20
palette_comb 19, 19, 9
palette_comb 3, 3, 11
palette_comb 17, 17, 2
palette_comb 4, 4, 2
palette_comb 4, 4, 3
palette_comb 28, 28, 0
palette_comb 3, 3, 0
palette_comb 0, 0, 1
palette_comb 18, 22, 18
palette_comb 20, 22, 20
palette_comb 24, 22, 24
palette_comb 16, 22, 8
palette_comb 17, 4, 13
palette_comb 27, 0, 14
palette_comb 27, 4, 15
palette_comb 19, 22, 9
palette_comb 16, 28, 10
palette_comb 4, 23, 28
palette_comb 17, 22, 2
palette_comb 4, 0, 2
palette_comb 4, 28, 3
palette_comb 28, 3, 0
palette_comb 3, 28, 4
palette_comb 21, 28, 4
palette_comb 3, 28, 0
palette_comb 25, 3, 28
palette_comb 0, 28, 8
palette_comb 4, 3, 28
palette_comb 28, 3, 6
palette_comb 4, 28, 29
; Sameboy "Exclusives"
palette_comb 30, 30, 30 ; CGA
palette_comb 31, 31, 31 ; DMG LCD
palette_comb 28, 4, 1
palette_comb 0, 0, 2
Palettes:
dw $7FFF, $32BF, $00D0, $0000
dw $639F, $4279, $15B0, $04CB
dw $7FFF, $6E31, $454A, $0000
dw $7FFF, $1BEF, $0200, $0000
dw $7FFF, $421F, $1CF2, $0000
dw $7FFF, $5294, $294A, $0000
dw $7FFF, $03FF, $012F, $0000
dw $7FFF, $03EF, $01D6, $0000
dw $7FFF, $42B5, $3DC8, $0000
dw $7E74, $03FF, $0180, $0000
dw $67FF, $77AC, $1A13, $2D6B
dw $7ED6, $4BFF, $2175, $0000
dw $53FF, $4A5F, $7E52, $0000
dw $4FFF, $7ED2, $3A4C, $1CE0
dw $03ED, $7FFF, $255F, $0000
dw $036A, $021F, $03FF, $7FFF
dw $7FFF, $01DF, $0112, $0000
dw $231F, $035F, $00F2, $0009
dw $7FFF, $03EA, $011F, $0000
dw $299F, $001A, $000C, $0000
dw $7FFF, $027F, $001F, $0000
dw $7FFF, $03E0, $0206, $0120
dw $7FFF, $7EEB, $001F, $7C00
dw $7FFF, $3FFF, $7E00, $001F
dw $7FFF, $03FF, $001F, $0000
dw $03FF, $001F, $000C, $0000
dw $7FFF, $033F, $0193, $0000
dw $0000, $4200, $037F, $7FFF
dw $7FFF, $7E8C, $7C00, $0000
dw $7FFF, $1BEF, $6180, $0000
; Sameboy "Exclusives"
dw $7FFF, $7FEA, $7D5F, $0000 ; CGA 1
dw $1B77, $0AD2, $25E9, $1545 ; DMG LCD
KeyCombinationPalettes
db 1 ; Right
db 48 ; Left
db 5 ; Up
db 8 ; Down
db 0 ; Right + A
db 40 ; Left + A
db 43 ; Up + A
db 3 ; Down + A
db 6 ; Right + B
db 7 ; Left + B
db 28 ; Up + B
db 49 ; Down + B
; Sameboy "Exclusives"
db 51 ; Right + A + B
db 52 ; Left + A + B
db 53 ; Up + A + B
db 54 ; Down + A + B
TrademarkSymbol:
db $3c,$42,$b9,$a5,$b9,$a5,$42,$3c
DMGPalettes:
dw $7FFF, $32BF, $00D0, $0000
; Helper Functions
DoubleBitsAndWriteRow:
; Double the most significant 4 bits, b is shifted by 4
ld a, 4
ld c, 0
.doubleCurrentBit
sla b
push af
rl c
pop af
rl c
dec a
jr nz, .doubleCurrentBit
ld a, c
; Write as two rows
ldi [hl], a
inc hl
ldi [hl], a
inc hl
ret
WaitFrame:
push hl
ld hl, $FF0F
res 0, [hl]
.wait
bit 0, [hl]
jr z, .wait
pop hl
ret
PlaySound:
ldh [$13], a
ld a, $87
ldh [$14], a
ret
; Clear from HL to HL | 0x2000
ClearMemoryPage:
ldi [hl], a
bit 5, h
jr z, ClearMemoryPage
ret
; c = $f0 for even lines, $f for odd lines.
ReadTileLine:
ld a, [de]
and c
ld b, a
inc e
inc e
ld a, [de]
dec e
dec e
and c
swap a
or b
bit 0, c
jr z, .dontSwap
swap a
.dontSwap
inc hl
ldi [hl], a
ret
ReadCGBLogoHalfTile:
ld c, $f0
call ReadTileLine
ld c, $f
call ReadTileLine
inc e
ld c, $f0
call ReadTileLine
ld c, $f
call ReadTileLine
inc e
ret
ReadCGBLogoTile:
call ReadCGBLogoHalfTile
ld a, e
add a, 22
ld e, a
call ReadCGBLogoHalfTile
ld a, e
sub a, 22
ld e, a
ret
ReadTrademarkSymbol:
ld de, TrademarkSymbol
ld c,$08
.loadTrademarkSymbolLoop:
ld a,[de]
inc de
ldi [hl],a
inc hl
dec c
jr nz, .loadTrademarkSymbolLoop
ret
LoadObjPalettes:
ld c, $6A
jr LoadPalettes
LoadBGPalettes:
ld c, $68
LoadPalettes:
ld a, $80
or e
ld [c], a
inc c
.loop
ld a, [hli]
ld [c], a
dec d
jr nz, .loop
ret
Preboot:
call ClearVRAMViaHDMA
; Select the first bank
xor a
ldh [$4F], a
call ClearVRAMViaHDMA
ld a, [$143]
bit 7, a
jr nz, .cgbGame
call EmulateDMG
.cgbGame
ldh [$4C], a ; One day, I will know what this switch does and how it differs from FF6C
ld a, $11
ret
EmulateDMG:
ld a, 1
ldh [$6C], a ; DMG Emulation
call GetPaletteIndex
bit 7, a
call nz, LoadDMGTilemap
and $7F
call WaitFrame
call LoadPalettesFromIndex
ld a, 4
ret
GetPaletteIndex:
ld a, [$14B] ; Old Licensee
cp $33
jr z, .newLicensee
cp 1 ; Nintendo
jr nz, .notNintendo
jr .doChecksum
.newLicensee
ld a, [$144]
cp "0"
jr nz, .notNintendo
ld a, [$145]
cp "1"
jr nz, .notNintendo
.doChecksum
ld hl, $134
ld c, $10
ld b, 0
.checksumLoop
ld a, [hli]
add b
ld b, a
dec c
jr nz, .checksumLoop
; c = 0
ld hl, TitleChecksums
.searchLoop
ld a, l
cp ChecksumsEnd & $FF
jr z, .notNintendo
ld a, [hli]
cp b
jr nz, .searchLoop
; We might have a match, Do duplicate/4th letter check
ld a, l
sub FirstChecksumWithDuplicate - TitleChecksums
jr c, .match ; Does not have a duplicate, must be a match!
; Has a duplicate; check 4th letter
push hl
ld a, l
add Dups4thLetterArray - FirstChecksumWithDuplicate - 1 ; -1 since hl was incremented
ld l, a
ld a, [hl]
pop hl
ld c, a
ld a, [$134 + 3] ; Get 4th letter
cp c
jr nz, .searchLoop ; Not a match, continue
.match
ld a, l
add PalettePerChecksum - TitleChecksums - 1; -1 since hl was incremented
ld l, a
ld a, [hl]
ret
.notNintendo
xor a
ret
LoadPalettesFromIndex: ; a = index of combination
ld b, a
; Multiply by 3
add b
add b
ld hl, PaletteCombinations
ld b, 0
ld c, a
add hl, bc
; Obj Palettes
ld e, 0
.loadObjPalette
ld a, [hli]
push hl
ld hl, Palettes
ld b, 0
ld c, a
add hl, bc
ld d, 8
call LoadObjPalettes
pop hl
bit 3, e
jr nz, .loadBGPalette
ld e, 8
jr .loadObjPalette
.loadBGPalette
;BG Palette
ld a, [hli]
ld hl, Palettes
ld b, 0
ld c, a
add hl, bc
ld d, 8
ld e, 0
call LoadBGPalettes
ret
ClearVRAMViaHDMA:
ld hl, $FF51
; Src
ld a, $D0
ld [hli], a
xor a
ld [hli], a
; Dest
ld a, $98
ld [hli], a
ld a, $A0
ld [hli], a
; Do it
ld a, $12
ld [hli], a
ret
LoadDMGTilemap:
push af
call WaitFrame
ld a,$19 ; Trademark symbol
ld [$9910], a ; ... put in the superscript position
ld hl,$992f ; Bottom right corner of the logo
ld c,$c ; Tiles in a logo row
.tilemapLoop
dec a
jr z, .tilemapDone
ldd [hl], a
dec c
jr nz, .tilemapLoop
ld l,$0f ; Jump to top row
jr .tilemapLoop
.tilemapDone
pop af
ret
SECTION "ROMMax", ROM0[$900]
; Prevent us from overflowing
ds 1
SECTION "RAM", WRAM0[$C000]
BgPalettes:
ds 8 * 4 * 2