GB MBC: Add NT (old 1) support

CHANGES

@@ -1,4 +1,6 @@
 0.11.0: (Future)
+Features:
+ - New unlicensed GB mapper: NT (older type 1)
 Other fixes:
  - Qt: Manually split filename to avoid overzealous splitting (fixes mgba.io/i/2681)
  - Qt: Expand criteria for tag branch names (fixes mgba.io/i/2679)

include/mgba/gb/interface.h

@@ -41,6 +41,7 @@ enum GBMemoryBankControllerType {
 	GB_MBC5_RUMBLE = 0x105,
 	GB_UNL_WISDOM_TREE = 0x200,
 	GB_UNL_PKJD = 0x203,
+	GB_UNL_NT_OLD_1 = 0x210,
 	GB_UNL_NT_NEW = 0x212,
 	GB_UNL_BBD = 0x220, // Also used as a mask for MBCs that need special read behavior
 	GB_UNL_HITEK = 0x221,

include/mgba/internal/gb/memory.h

@@ -238,6 +238,12 @@ struct GBPKJDState {
 	uint8_t reg[2];
 };
 
+struct GBNTOld1State {
+	bool swapped;
+	uint8_t baseBank;
+	uint8_t bankCount;
+};
+
 struct GBNTNewState {
 	bool splitMode;
 };
@@ -263,6 +269,7 @@ union GBMBCState {
 	struct GBPocketCamState pocketCam;
 	struct GBTAMA5State tama5;
 	struct GBHuC3State huc3;
+	struct GBNTOld1State ntOld1;
 	struct GBNTNewState ntNew;
 	struct GBPKJDState pkjd;
 	struct GBBBDState bbd;

include/mgba/internal/gb/serialize.h

@@ -416,6 +416,11 @@ struct GBSerializedState {
 				uint8_t value;
 				uint8_t mode;
 			} huc3;
+			struct {
+				uint8_t swapped;
+				uint8_t baseBank;
+				uint8_t bankCount;
+			} ntOld1;
 			struct {
 				uint8_t dataSwapMode;
 				uint8_t bankSwapMode;

src/gb/mbc.c

@@ -45,6 +45,7 @@ static void _GBPocketCam(struct GB* gb, uint16_t address, uint8_t value);
 static void _GBTAMA5(struct GB* gb, uint16_t address, uint8_t value);
 static void _GBWisdomTree(struct GB* gb, uint16_t address, uint8_t value);
 static void _GBPKJD(struct GB* gb, uint16_t address, uint8_t value);
+static void _GBNTOld1(struct GB* gb, uint16_t address, uint8_t value);
 static void _GBNTNew(struct GB* gb, uint16_t address, uint8_t value);
 static void _GBBBD(struct GB* gb, uint16_t address, uint8_t value);
 static void _GBHitek(struct GB* gb, uint16_t address, uint8_t value);
@@ -159,7 +160,7 @@ static struct {
 	{"BBD", GB_UNL_BBD},
 	{"HITK", GB_UNL_HITEK},
 	{"SNTX", GB_MBC_AUTODETECT}, // TODO
-	{"NTO1", GB_MBC_AUTODETECT}, // TODO
+	{"NTO1", GB_UNL_NT_OLD_1},
 	{"NTO2", GB_MBC_AUTODETECT}, // TODO
 	{"NTN", GB_UNL_NT_NEW},
 	{"LICH", GB_MBC_AUTODETECT}, // TODO
@@ -486,6 +487,9 @@ void GBMBCInit(struct GB* gb) {
 	case GB_UNL_WISDOM_TREE:
 		gb->memory.mbcWrite = _GBWisdomTree;
 		break;
+	case GB_UNL_NT_OLD_1:
+		gb->memory.mbcWrite = _GBNTOld1;
+		break;
 	case GB_UNL_NT_NEW:
 		gb->memory.mbcWrite = _GBNTNew;
 		break;
@@ -1963,6 +1967,100 @@ static uint8_t _GBPKJDRead(struct GBMemory* memory, uint16_t address) {
 	}
 }
 
+
+static uint8_t _reorderBits(uint8_t input, const uint8_t* reorder) {
+	uint8_t newbyte = 0;
+	int i;
+	for(i = 0; i < 8; ++i) {
+		int oldbit = reorder[i];
+		int newbit = i;
+		newbyte += ((input >> oldbit) & 1) << newbit;
+	}
+
+	return newbyte;
+}
+
+static const uint8_t _ntOld1Reorder[8] = {
+	0, 2, 1, 4, 3, 5, 6, 7
+};
+
+void _GBNTOld1(struct GB* gb, uint16_t address, uint8_t value) {
+	struct GBMemory* memory = &gb->memory;
+	struct GBNTOld1State* mbcState = &memory->mbcState.ntOld1;
+	int bank = value;
+
+	switch (address >> 12) {
+	case 0x0:
+	case 0x1:
+		_GBMBC3(gb, address, value);
+		break;
+	case 0x2:
+	case 0x3:
+		bank &= 0x1F;
+		if (!bank) {
+			bank = 1;
+		}
+		if (mbcState->swapped) {
+			bank = _reorderBits(bank, _ntOld1Reorder);
+		}
+		if (mbcState->bankCount) {
+			bank &= mbcState->bankCount - 1;
+		}
+		GBMBCSwitchBank(gb, bank + mbcState->baseBank);
+		return;
+	case 0x5:
+		switch (address & 3) {
+		case 0:
+			mLOG(GB_MBC, STUB, "Unimplemented NT Old 1 address 0");
+			break;
+		case 1:
+			value &= 0x3F;
+			mbcState->baseBank = value * 2;
+			if (mbcState->baseBank) {
+				GBMBCSwitchBank0(gb, mbcState->baseBank);
+				GBMBCSwitchBank(gb, mbcState->baseBank + 1);
+			}
+			break;
+		case 2:
+			if ((value & 0xF0) == 0xE0) {
+				gb->sramSize = 0x2000;
+				GBResizeSram(gb, gb->sramSize);
+			}
+			switch (value & 0xF) {
+			case 0x00:
+				mbcState->bankCount = 32;
+				break;
+			case 0x08:
+				mbcState->bankCount = 16;
+				break;
+			case 0xC:
+				mbcState->bankCount = 8;
+				break;
+			case 0xE:
+				mbcState->bankCount = 4;
+				break;
+			case 0xF:
+				mbcState->bankCount = 2;
+				break;
+			default:
+				mbcState->bankCount = 32;
+				break;
+			}
+			break;
+		case 3:
+			mbcState->swapped = !!(value & 0x10);
+
+			bank = memory->currentBank;
+			if (mbcState->swapped) {
+				bank = _reorderBits(bank, _ntOld1Reorder);
+			}
+			GBMBCSwitchBank(gb, bank);
+			break;
+		}
+		return;
+	}
+}
+
 void _GBNTNew(struct GB* gb, uint16_t address, uint8_t value) {
 	struct GBMemory* memory = &gb->memory;
 	if (address >> 8 == 0x14) {
@@ -1986,18 +2084,6 @@ void _GBNTNew(struct GB* gb, uint16_t address, uint8_t value) {
 	_GBMBC5(gb, address, value);
 }
 
-static uint8_t _reorderBits(uint8_t input, const uint8_t* reorder) {
-	uint8_t newbyte = 0;
-	int i;
-	for(i = 0; i < 8; ++i) {
-		int oldbit = reorder[i];
-		int newbit = i;
-		newbyte += ((input >> oldbit) & 1) << newbit;
-	}
-
-	return newbyte;
-}
-
 static const uint8_t _bbdDataReordering[8][8] = {
 	{ 0, 1, 2, 3, 4, 5, 6, 7 }, // 00 - Normal
 	{ 0, 1, 2, 3, 4, 5, 6, 7 }, // 01 - NOT KNOWN YET

src/gb/memory.c

@@ -797,6 +797,11 @@ void GBMemorySerialize(const struct GB* gb, struct GBSerializedState* state) {
 		state->memory.mmm01.locked = memory->mbcState.mmm01.locked;
 		state->memory.mmm01.bank0 = memory->mbcState.mmm01.currentBank0;
 		break;
+	case GB_UNL_NT_OLD_1:
+		state->memory.ntOld1.swapped = memory->mbcState.ntOld1.swapped;
+		state->memory.ntOld1.baseBank = memory->mbcState.ntOld1.baseBank;
+		state->memory.ntOld1.bankCount = memory->mbcState.ntOld1.bankCount;
+		break;
 	case GB_UNL_BBD:
 	case GB_UNL_HITEK:
 		state->memory.bbd.dataSwapMode = memory->mbcState.bbd.dataSwapMode;
@@ -929,6 +934,12 @@ void GBMemoryDeserialize(struct GB* gb, const struct GBSerializedState* state) {
 			GBMBCSwitchBank0(gb, gb->memory.romSize / GB_SIZE_CART_BANK0 - 2);
 		}
 		break;
+	case GB_UNL_NT_OLD_1:
+		memory->mbcState.ntOld1.swapped = state->memory.ntOld1.swapped;
+		memory->mbcState.ntOld1.baseBank = state->memory.ntOld1.baseBank;
+		memory->mbcState.ntOld1.bankCount = state->memory.ntOld1.bankCount;
+		GBMBCSwitchBank0(gb, memory->mbcState.ntOld1.baseBank);
+		break;
 	case GB_UNL_BBD:
 	case GB_UNL_HITEK:
 		memory->mbcState.bbd.dataSwapMode = state->memory.bbd.dataSwapMode & 0x7;

src/gb/overrides.c

@@ -673,6 +673,8 @@ static const struct GBCartridgeOverride _overrides[] = {
 	{ 0x5AFF0038, GB_MODEL_AUTODETECT, GB_MBC3_RTC, { 0 } }, // Silver (debug)
 	{ 0xA61856BD, GB_MODEL_AUTODETECT, GB_MBC3_RTC, { 0 } }, // Silver (non-debug)
 	{ 0x30F8F86C, GB_MODEL_AUTODETECT, GB_UNL_PKJD, { 0 } }, // Pokemon Jade Version (Telefang Speed bootleg)
+	{ 0xE1147E75, GB_MODEL_AUTODETECT, GB_UNL_NT_OLD_1, { 0 } }, // Rockman 8
+	{ 0xEFF88FAA, GB_MODEL_AUTODETECT, GB_UNL_NT_OLD_1, { 0 } }, // True Color 25 in 1 (NT-9920)
 	{ 0xB289D95A, GB_MODEL_AUTODETECT, GB_UNL_NT_NEW, { 0 } }, // Capcom vs SNK - Millennium Fight 2001
 	{ 0x688D6713, GB_MODEL_AUTODETECT, GB_UNL_NT_NEW, { 0 } }, // Digimon 02 4
 	{ 0x8931A272, GB_MODEL_AUTODETECT, GB_UNL_NT_NEW, { 0 } }, // Digimon 2

src/platform/qt/GameBoy.cpp

@@ -35,6 +35,7 @@ static const QList<GBMemoryBankControllerType> s_mbcList{
 	GB_HuC3,
 	GB_UNL_WISDOM_TREE,
 	GB_UNL_PKJD,
+	GB_UNL_NT_OLD_1,
 	GB_UNL_NT_NEW,
 	GB_UNL_BBD,
 	GB_UNL_HITEK,
@@ -87,6 +88,7 @@ QString GameBoy::mbcName(GBMemoryBankControllerType mbc) {
 		s_mbcNames[GB_POCKETCAM] = tr("Pocket Cam");
 		s_mbcNames[GB_TAMA5] = tr("TAMA5");
 		s_mbcNames[GB_UNL_WISDOM_TREE] = tr("Wisdom Tree");
+		s_mbcNames[GB_UNL_NT_OLD_1] = tr("NT (old 1)");
 		s_mbcNames[GB_UNL_NT_NEW] = tr("NT (new)");
 		s_mbcNames[GB_UNL_PKJD] = tr("Pokémon Jade/Diamond");
 		s_mbcNames[GB_UNL_BBD] = tr("BBD");