GB MBC: Partial HuC-1 support

CHANGES

@@ -15,6 +15,7 @@ Features:
  - Ability to select GB/GBC/SGB BIOS on console ports
  - Optional automatic state saving/loading
  - Access to ur0 and uma0 partitions on the Vita
+ - Partial support for MBC6, TAMA and HuC-1 GB mappers
 Bugfixes:
  - GB Audio: Make audio unsigned with bias (fixes mgba.io/i/749)
  - GB Serialize: Fix audio state loading

README.md

@@ -52,14 +52,14 @@ The following mappers are fully supported:
 
 The following mappers are partially supported:
 
+- MBC6
 - Pocket Cam
 - TAMA5
+- HuC-1
 - HuC-3
 
 The following mappers are not currently supported:
 
-- MBC6
-- HuC-1
 - MMM01
 
 ### Planned features

src/gb/mbc.c

@@ -27,6 +27,7 @@ static void _GBMBC3(struct GB*, uint16_t address, uint8_t value);
 static void _GBMBC5(struct GB*, uint16_t address, uint8_t value);
 static void _GBMBC6(struct GB*, uint16_t address, uint8_t value);
 static void _GBMBC7(struct GB*, uint16_t address, uint8_t value);
+static void _GBHuC1(struct GB*, uint16_t address, uint8_t value);
 static void _GBHuC3(struct GB*, uint16_t address, uint8_t value);
 static void _GBPocketCam(struct GB* gb, uint16_t address, uint8_t value);
 static void _GBTAMA5(struct GB* gb, uint16_t address, uint8_t value);
@@ -259,8 +260,7 @@ void GBMBCInit(struct GB* gb) {
 		gb->memory.mbcWrite = _GBMBC1;
 		break;
 	case GB_HuC1:
-		mLOG(GB_MBC, WARN, "unimplemented MBC: HuC-1");
-		gb->memory.mbcWrite = _GBMBC1;
+		gb->memory.mbcWrite = _GBHuC1;
 		break;
 	case GB_HuC3:
 		gb->memory.mbcWrite = _GBHuC3;
@@ -821,6 +821,34 @@ static void _GBMBC7Write(struct GBMemory* memory, uint16_t address, uint8_t valu
 	mbc7->eeprom = value;
 }
 
+void _GBHuC1(struct GB* gb, uint16_t address, uint8_t value) {
+	struct GBMemory* memory = &gb->memory;
+	int bank = value & 0x3F;
+	switch (address >> 13) {
+	case 0x0:
+		switch (value) {
+		case 0xE:
+			memory->sramAccess = false;
+			break;
+		default:
+			memory->sramAccess = true;
+			GBMBCSwitchSramBank(gb, memory->sramCurrentBank);
+			break;
+		}
+		break;
+	case 0x1:
+		GBMBCSwitchBank(gb, bank);
+		break;
+	case 0x2:
+		GBMBCSwitchSramBank(gb, value);
+		break;
+	default:
+		// TODO
+		mLOG(GB_MBC, STUB, "HuC-1 unknown address: %04X:%02X", address, value);
+		break;
+	}
+}
+
 void _GBHuC3(struct GB* gb, uint16_t address, uint8_t value) {
 	struct GBMemory* memory = &gb->memory;
 	int bank = value & 0x3F;