1#include "gba-serialize.h"
  2
  3#include "gba-audio.h"
  4#include "gba-io.h"
  5#include "gba-thread.h"
  6
  7#include "util/memory.h"
  8
  9#include <fcntl.h>
 10
 11const uint32_t GBA_SAVESTATE_MAGIC = 0x01000000;
 12
 13void GBASerialize(struct GBA* gba, struct GBASerializedState* state) {
 14	state->versionMagic = GBA_SAVESTATE_MAGIC;
 15	state->biosChecksum = gba->biosChecksum;
 16	state->id = ((struct GBACartridge*) gba->memory.rom)->id;
 17	memcpy(state->title, ((struct GBACartridge*) gba->memory.rom)->title, sizeof(state->title));
 18
 19	memcpy(state->cpu.gprs, gba->cpu->gprs, sizeof(state->cpu.gprs));
 20	state->cpu.cpsr = gba->cpu->cpsr;
 21	state->cpu.spsr = gba->cpu->spsr;
 22	state->cpu.cycles = gba->cpu->cycles;
 23	state->cpu.nextEvent = gba->cpu->nextEvent;
 24	memcpy(state->cpu.bankedRegisters, gba->cpu->bankedRegisters, 6 * 7 * sizeof(int32_t));
 25	memcpy(state->cpu.bankedSPSRs, gba->cpu->bankedSPSRs, 6 * sizeof(int32_t));
 26
 27	GBAMemorySerialize(&gba->memory, state);
 28	GBAIOSerialize(gba, state);
 29	GBAVideoSerialize(&gba->video, state);
 30	GBAAudioSerialize(&gba->audio, state);
 31}
 32
 33void GBADeserialize(struct GBA* gba, struct GBASerializedState* state) {
 34	if (state->versionMagic != GBA_SAVESTATE_MAGIC) {
 35		GBALog(gba, GBA_LOG_WARN, "Invalid or too new savestate");
 36		return;
 37	}
 38	if (state->biosChecksum != gba->biosChecksum) {
 39		GBALog(gba, GBA_LOG_WARN, "Savestate created using a different version of the BIOS");
 40		if (state->cpu.gprs[ARM_PC] < SIZE_BIOS && state->cpu.gprs[ARM_PC] >= 0x20) {
 41			return;
 42		}
 43	}
 44	if (state->id != ((struct GBACartridge*) gba->memory.rom)->id || memcmp(state->title, ((struct GBACartridge*) gba->memory.rom)->title, sizeof(state->title))) {
 45		GBALog(gba, GBA_LOG_WARN, "Savestate is for a different game");
 46		return;
 47	}
 48	memcpy(gba->cpu->gprs, state->cpu.gprs, sizeof(gba->cpu->gprs));
 49	gba->cpu->cpsr = state->cpu.cpsr;
 50	gba->cpu->spsr = state->cpu.spsr;
 51	gba->cpu->cycles = state->cpu.cycles;
 52	gba->cpu->nextEvent = state->cpu.nextEvent;
 53	memcpy(gba->cpu->bankedRegisters, state->cpu.bankedRegisters, 6 * 7 * sizeof(int32_t));
 54	memcpy(gba->cpu->bankedSPSRs, state->cpu.bankedSPSRs, 6 * sizeof(int32_t));
 55	gba->cpu->executionMode = gba->cpu->cpsr.t ? MODE_THUMB : MODE_ARM;
 56	gba->cpu->privilegeMode = gba->cpu->cpsr.priv;
 57	gba->cpu->memory.setActiveRegion(gba->cpu, gba->cpu->gprs[ARM_PC]);
 58
 59	GBAMemoryDeserialize(&gba->memory, state);
 60	GBAIODeserialize(gba, state);
 61	GBAVideoDeserialize(&gba->video, state);
 62	GBAAudioDeserialize(&gba->audio, state);
 63}
 64
 65static int _getStateFd(struct GBA* gba, int slot) {
 66	char path[PATH_MAX];
 67	path[PATH_MAX - 1] = '\0';
 68	snprintf(path, PATH_MAX - 1, "%s.ss%d", gba->activeFile, slot);
 69	int fd = open(path, O_CREAT | O_RDWR, 0777);
 70	if (fd >= 0) {
 71		ftruncate(fd, sizeof(struct GBASerializedState));
 72	}
 73	return fd;
 74}
 75
 76bool GBASaveState(struct GBA* gba, int slot) {
 77	int fd = _getStateFd(gba, slot);
 78	if (fd < 0) {
 79		return false;
 80	}
 81	struct GBASerializedState* state = GBAMapState(fd);
 82	GBASerialize(gba, state);
 83	GBADeallocateState(state);
 84	close(fd);
 85	return true;
 86}
 87
 88bool GBALoadState(struct GBA* gba, int slot) {
 89	int fd = _getStateFd(gba, slot);
 90	if (fd < 0) {
 91		return false;
 92	}
 93	struct GBASerializedState* state = GBAMapState(fd);
 94	GBADeserialize(gba, state);
 95	GBADeallocateState(state);
 96	close(fd);
 97	return true;
 98}
 99
100struct GBASerializedState* GBAMapState(int fd) {
101	return fileMemoryMap(fd, sizeof(struct GBASerializedState), MEMORY_WRITE);
102}
103
104struct GBASerializedState* GBAAllocateState(void) {
105	return anonymousMemoryMap(sizeof(struct GBASerializedState));
106}
107
108void GBADeallocateState(struct GBASerializedState* state) {
109	mappedMemoryFree(state, sizeof(struct GBASerializedState));
110}
111
112void GBARecordFrame(struct GBAThread* thread) {
113	int offset = thread->rewindBufferWriteOffset;
114	struct GBASerializedState* state = thread->rewindBuffer[offset];
115	if (!state) {
116		state = GBAAllocateState();
117		thread->rewindBuffer[offset] = state;
118	}
119	GBASerialize(thread->gba, state);
120	thread->rewindBufferSize = thread->rewindBufferSize == thread->rewindBufferCapacity ? thread->rewindBufferCapacity : thread->rewindBufferSize + 1;
121	thread->rewindBufferWriteOffset = (offset + 1) % thread->rewindBufferCapacity;
122}
123
124void GBARewind(struct GBAThread* thread, int nStates) {
125	if (nStates > thread->rewindBufferSize || nStates < 0) {
126		nStates = thread->rewindBufferSize;
127	}
128	if (nStates == 0) {
129		return;
130	}
131	int offset = thread->rewindBufferWriteOffset - nStates;
132	if (offset < 0) {
133		offset += thread->rewindBufferSize;
134	}
135	struct GBASerializedState* state = thread->rewindBuffer[offset];
136	if (!state) {
137		return;
138	}
139	thread->rewindBufferSize -= nStates;
140	thread->rewindBufferWriteOffset = (offset + thread->rewindBufferCapacity - nStates) % thread->rewindBufferCapacity;
141	GBADeserialize(thread->gba, state);
142}