Start implementing save games

src/gba/gba-memory.c

@@ -40,6 +40,8 @@ void GBAMemoryInit(struct GBAMemory* memory) {
 		memory->p->errstr = GBA_CANNOT_MMAP;
 	}
 
+	GBASavedataInit(&memory->savedata, "test.sav");
+
 	int i;
 	for (i = 0; i < 16; ++i) {
 		memory->waitstates16[i] = GBA_BASE_WAITSTATES[i];
@@ -65,6 +67,7 @@ void GBAMemoryInit(struct GBAMemory* memory) {
 void GBAMemoryDeinit(struct GBAMemory* memory) {
 	munmap(memory->wram, SIZE_WORKING_RAM);
 	munmap(memory->iwram, SIZE_WORKING_IRAM);
+	GBASavedataDeinit(&memory->savedata);
 }
 
 static void GBASetActiveRegion(struct ARMMemory* memory, uint32_t address) {
@@ -230,7 +233,10 @@ int8_t GBALoad8(struct ARMMemory* memory, uint32_t address) {
 	case BASE_CART2_EX:
 		return ((int8_t*) gbaMemory->rom)[address & (SIZE_CART0 - 1)];
 	case BASE_CART_SRAM:
-		break;
+		if (gbaMemory->savedata.type == SAVEDATA_NONE) {
+			GBASavedataInitSRAM(&gbaMemory->savedata);
+		}
+		return gbaMemory->savedata.data[address & (SIZE_CART_SRAM - 1)];
 	default:
 		break;
 	}
@@ -266,7 +272,10 @@ uint8_t GBALoadU8(struct ARMMemory* memory, uint32_t address) {
 	case BASE_CART2_EX:
 		return ((uint8_t*) gbaMemory->rom)[address & (SIZE_CART0 - 1)];
 	case BASE_CART_SRAM:
-		break;
+		if (gbaMemory->savedata.type == SAVEDATA_NONE) {
+			GBASavedataInitSRAM(&gbaMemory->savedata);
+		}
+		return gbaMemory->savedata.data[address & (SIZE_CART_SRAM - 1)];
 	default:
 		break;
 	}
@@ -367,6 +376,18 @@ void GBAStore8(struct ARMMemory* memory, uint32_t address, int8_t value) {
 	case BASE_CART2_EX:
 		break;
 	case BASE_CART_SRAM:
+		if (gbaMemory->savedata.type == SAVEDATA_NONE) {
+			if (address == SAVEDATA_FLASH_BASE) {
+				GBASavedataInitFlash(&gbaMemory->savedata);
+			} else {
+				GBASavedataInitSRAM(&gbaMemory->savedata);
+			}
+		}
+		if (gbaMemory->savedata.type == SAVEDATA_FLASH512 || gbaMemory->savedata.type == SAVEDATA_FLASH1M) {
+			GBASavedataWriteFlash(&gbaMemory->savedata, value);
+		} else if (gbaMemory->savedata.type == SAVEDATA_SRAM) {
+			gbaMemory->savedata.data[address & (SIZE_CART_SRAM - 1)] = value;
+		}
 		break;
 	default:
 		break;

src/gba/gba-memory.h

@@ -3,6 +3,8 @@
 
 #include "arm.h"
 
+#include "gba-savedata.h"
+
 enum GBAMemoryRegion {
 	REGION_BIOS = 0x0,
 	REGION_WORKING_RAM = 0x2,
@@ -108,6 +110,8 @@ struct GBAMemory {
 	uint32_t* rom;
 	uint16_t io[SIZE_IO >> 1];
 
+	struct GBASavedata savedata;
+
 	char waitstates32[256];
 	char waitstates16[256];
 	char waitstatesSeq32[256];

src/gba/gba-savedata.c

@@ -0,0 +1,80 @@
+#include "gba-savedata.h"
+
+#include "gba.h"
+
+#include <fcntl.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <unistd.h>
+
+void GBASavedataInit(struct GBASavedata* savedata, const char* filename) {
+	savedata->type = SAVEDATA_NONE;
+	savedata->data = 0;
+	savedata->fd = -1;
+	savedata->filename = filename;
+}
+
+void GBASavedataDeinit(struct GBASavedata* savedata) {
+	switch (savedata->type) {
+	case SAVEDATA_SRAM:
+		munmap(savedata->data, SIZE_CART_SRAM);
+		break;
+	case SAVEDATA_FLASH512:
+		munmap(savedata->data, SIZE_CART_FLASH512);
+		break;
+	case SAVEDATA_FLASH1M:
+		munmap(savedata->data, SIZE_CART_FLASH1M);
+		break;
+	case SAVEDATA_EEPROM:
+		munmap(savedata->data, SIZE_CART_EEPROM);
+		break;
+	default:
+		break;
+	}
+	close(savedata->fd);
+	savedata->type = SAVEDATA_NONE;
+}
+
+void GBASavedataInitFlash(struct GBASavedata* savedata) {
+	savedata->type = SAVEDATA_FLASH512;
+	savedata->fd = open(savedata->filename, O_RDWR | O_CREAT, 0666);
+	if (savedata->fd < 0) {
+		GBALog(GBA_LOG_WARN, "Cannot open savedata file %s", savedata->filename);
+		return;
+	}
+	// mmap enough so that we can expand the file if we need to
+	savedata->data = mmap(0, SIZE_CART_FLASH1M, PROT_READ | PROT_WRITE, 0, savedata->fd, 0);
+
+	off_t end = lseek(savedata->fd, 0, SEEK_END);
+	if (end < SIZE_CART_FLASH512) {
+		ftruncate(savedata->fd, SIZE_CART_SRAM);
+		memset(&savedata->data[end], 0xFF, SIZE_CART_SRAM - end);
+	}
+}
+
+void GBASavedataInitSRAM(struct GBASavedata* savedata) {
+	savedata->type = SAVEDATA_SRAM;
+	savedata->fd = open(savedata->filename, O_RDWR | O_CREAT, 0666);
+	off_t end;
+	int flags = MAP_SHARED;
+	if (savedata->fd < 0) {
+		GBALog(GBA_LOG_WARN, "Cannot open savedata file %s", savedata->filename);
+		end = 0;
+		flags |= MAP_ANON;
+	} else {
+		end = lseek(savedata->fd, 0, SEEK_END);
+		if (end < SIZE_CART_SRAM) {
+			ftruncate(savedata->fd, SIZE_CART_SRAM);
+		}
+	}
+	savedata->data = mmap(0, SIZE_CART_SRAM, PROT_READ | PROT_WRITE, flags, savedata->fd, 0);
+	if (end < SIZE_CART_SRAM) {
+		memset(&savedata->data[end], 0xFF, SIZE_CART_SRAM - end);
+	}
+}
+
+void GBASavedataWriteFlash(struct GBASavedata* savedata, uint8_t value) {
+	(void)(savedata);
+	(void)(value);
+	GBALog(GBA_LOG_STUB, "Flash memory unimplemented");
+}

src/gba/gba-savedata.h

@@ -0,0 +1,33 @@
+#ifndef GBA_SAVEDATA_H
+#define GBA_SAVEDATA_H
+
+#include <stdint.h>
+
+enum SavedataType {
+	SAVEDATA_NONE = 0,
+	SAVEDATA_SRAM,
+	SAVEDATA_FLASH512,
+	SAVEDATA_FLASH1M,
+	SAVEDATA_EEPROM
+};
+
+enum {
+	SAVEDATA_FLASH_BASE = 0x0E005555
+};
+
+struct GBASavedata {
+	enum SavedataType type;
+	uint8_t* data;
+	const char* filename;
+	int fd;
+};
+
+void GBASavedataInit(struct GBASavedata* savedata, const char* filename);
+void GBASavedataDeinit(struct GBASavedata* savedata);
+
+void GBASavedataInitFlash(struct GBASavedata* savedata);
+void GBASavedataInitSRAM(struct GBASavedata* savedata);
+
+void GBASavedataWriteFlash(struct GBASavedata* savedata, uint8_t value);
+
+#endif