GBA Savedata: Support for 64 kiB SRAM saves

CHANGES

@@ -5,6 +5,7 @@ Features:
  - Tool for converting scanned pictures of e-Reader cards to raw dotcode data
  - Cheat code support in homebrew ports
  - Support for combo "Super Game Boy Color" SGB + GBC ROM hacks
+ - Support for 64 kiB SRAM saves used in some bootlegs
 Emulation fixes:
  - GB Video: Clear VRAM on reset (fixes mgba.io/i/2152)
  - GBA SIO: Add missing NORMAL8 implementation bits (fixes mgba.io/i/2172)

include/mgba/internal/gba/memory.h

@@ -68,6 +68,7 @@ enum {
 	SIZE_CART1 = 0x02000000,
 	SIZE_CART2 = 0x02000000,
 	SIZE_CART_SRAM = 0x00008000,
+	SIZE_CART_SRAM512 = 0x00010000,
 	SIZE_CART_FLASH512 = 0x00010000,
 	SIZE_CART_FLASH1M = 0x00020000,
 	SIZE_CART_EEPROM = 0x00002000,

include/mgba/internal/gba/savedata.h

@@ -24,7 +24,8 @@ enum SavedataType {
 	SAVEDATA_FLASH512 = 2,
 	SAVEDATA_FLASH1M = 3,
 	SAVEDATA_EEPROM = 4,
-	SAVEDATA_EEPROM512 = 5
+	SAVEDATA_EEPROM512 = 5,
+	SAVEDATA_SRAM512 = 6,
 };
 
 enum SavedataCommand {
@@ -110,6 +111,7 @@ void GBASavedataForceType(struct GBASavedata* savedata, enum SavedataType type);
 void GBASavedataInitFlash(struct GBASavedata* savedata);
 void GBASavedataInitEEPROM(struct GBASavedata* savedata);
 void GBASavedataInitSRAM(struct GBASavedata* savedata);
+void GBASavedataInitSRAM512(struct GBASavedata* savedata);
 
 uint8_t GBASavedataReadFlash(struct GBASavedata* savedata, uint16_t address);
 void GBASavedataWriteFlash(struct GBASavedata* savedata, uint16_t address, uint8_t value);

src/gba/memory.c

@@ -717,6 +717,8 @@ uint32_t GBALoad8(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
 			value = GBASavedataReadFlash(&memory->savedata, address);
 		} else if (memory->hw.devices & HW_TILT) {
 			value = GBAHardwareTiltRead(&memory->hw, address & OFFSET_MASK);
+		} else if (memory->savedata.type == SAVEDATA_SRAM512) {
+			value = memory->savedata.data[address & (SIZE_CART_SRAM512 - 1)];
 		} else {
 			mLOG(GBA_MEM, GAME_ERROR, "Reading from non-existent SRAM: 0x%08X", address);
 			value = 0xFF;
@@ -1070,6 +1072,9 @@ void GBAStore8(struct ARMCore* cpu, uint32_t address, int8_t value, int* cycleCo
 			memory->savedata.dirty |= SAVEDATA_DIRT_NEW;
 		} else if (memory->hw.devices & HW_TILT) {
 			GBAHardwareTiltWrite(&memory->hw, address & OFFSET_MASK, value);
+		} else if (memory->savedata.type == SAVEDATA_SRAM512) {
+			memory->savedata.data[address & (SIZE_CART_SRAM512 - 1)] = value;
+			memory->savedata.dirty |= SAVEDATA_DIRT_NEW;
 		} else {
 			mLOG(GBA_MEM, GAME_ERROR, "Writing to non-existent SRAM: 0x%08X", address);
 		}

src/gba/overrides.c

@@ -241,6 +241,9 @@ bool GBAOverrideFind(const struct Configuration* config, struct GBACartridgeOver
 			if (strcasecmp(savetype, "SRAM") == 0) {
 				found = true;
 				override->savetype = SAVEDATA_SRAM;
+			} else if (strcasecmp(savetype, "SRAM512") == 0) {
+				found = true;
+				override->savetype = SAVEDATA_SRAM512;
 			} else if (strcasecmp(savetype, "EEPROM") == 0) {
 				found = true;
 				override->savetype = SAVEDATA_EEPROM;
@@ -288,6 +291,9 @@ void GBAOverrideSave(struct Configuration* config, const struct GBACartridgeOver
 	case SAVEDATA_SRAM:
 		savetype = "SRAM";
 		break;
+	case SAVEDATA_SRAM512:
+		savetype = "SRAM512";
+		break;
 	case SAVEDATA_EEPROM:
 		savetype = "EEPROM";
 		break;

src/gba/savedata.c

@@ -68,6 +68,9 @@ void GBASavedataDeinit(struct GBASavedata* savedata) {
 		case SAVEDATA_SRAM:
 			mappedMemoryFree(savedata->data, SIZE_CART_SRAM);
 			break;
+		case SAVEDATA_SRAM512:
+			mappedMemoryFree(savedata->data, SIZE_CART_SRAM512);
+			break;
 		case SAVEDATA_FLASH512:
 			mappedMemoryFree(savedata->data, SIZE_CART_FLASH512);
 			break;
@@ -124,6 +127,8 @@ bool GBASavedataClone(struct GBASavedata* savedata, struct VFile* out) {
 		switch (savedata->type) {
 		case SAVEDATA_SRAM:
 			return out->write(out, savedata->data, SIZE_CART_SRAM) == SIZE_CART_SRAM;
+		case SAVEDATA_SRAM512:
+			return out->write(out, savedata->data, SIZE_CART_SRAM512) == SIZE_CART_SRAM512;
 		case SAVEDATA_FLASH512:
 			return out->write(out, savedata->data, SIZE_CART_FLASH512) == SIZE_CART_FLASH512;
 		case SAVEDATA_FLASH1M:
@@ -153,6 +158,8 @@ size_t GBASavedataSize(const struct GBASavedata* savedata) {
 	switch (savedata->type) {
 	case SAVEDATA_SRAM:
 		return SIZE_CART_SRAM;
+	case SAVEDATA_SRAM512:
+		return SIZE_CART_SRAM512;
 	case SAVEDATA_FLASH512:
 		return SIZE_CART_FLASH512;
 	case SAVEDATA_FLASH1M:
@@ -233,6 +240,9 @@ void GBASavedataForceType(struct GBASavedata* savedata, enum SavedataType type)
 	case SAVEDATA_SRAM:
 		GBASavedataInitSRAM(savedata);
 		break;
+	case SAVEDATA_SRAM512:
+		GBASavedataInitSRAM512(savedata);
+		break;
 	case SAVEDATA_FORCE_NONE:
 		savedata->type = SAVEDATA_FORCE_NONE;
 		break;
@@ -322,6 +332,30 @@ void GBASavedataInitSRAM(struct GBASavedata* savedata) {
 	}
 }
 
+void GBASavedataInitSRAM512(struct GBASavedata* savedata) {
+	if (savedata->type == SAVEDATA_AUTODETECT) {
+		savedata->type = SAVEDATA_SRAM512;
+	} else {
+		mLOG(GBA_SAVE, WARN, "Can't re-initialize savedata");
+		return;
+	}
+	off_t end;
+	if (!savedata->vf) {
+		end = 0;
+		savedata->data = anonymousMemoryMap(SIZE_CART_SRAM512);
+	} else {
+		end = savedata->vf->size(savedata->vf);
+		if (end < SIZE_CART_SRAM512) {
+			savedata->vf->truncate(savedata->vf, SIZE_CART_SRAM512);
+		}
+		savedata->data = savedata->vf->map(savedata->vf, SIZE_CART_SRAM512, savedata->mapMode);
+	}
+
+	if (end < SIZE_CART_SRAM512) {
+		memset(&savedata->data[end], 0xFF, SIZE_CART_SRAM512 - end);
+	}
+}
+
 uint8_t GBASavedataReadFlash(struct GBASavedata* savedata, uint16_t address) {
 	if (savedata->command == FLASH_COMMAND_ID) {
 		if (savedata->type == SAVEDATA_FLASH512) {

src/platform/qt/OverrideView.ui

@@ -151,6 +151,11 @@
                 <string>EEPROM 512 bytes</string>
                </property>
               </item>
+              <item>
+               <property name="text">
+                <string>SRAM 64kB (bootlegs only)</string>
+               </property>
+              </item>
              </widget>
             </item>
             <item row="2" column="0">