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GBA Memory: Optimize DMA

This commit is contained in:
Jeffrey Pfau 2016-10-31 02:37:00 -07:00
parent fa3d263dd9
commit d08a0fef01
1 changed files with 11 additions and 25 deletions
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36
src/gba/memory.c
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@ -1643,9 +1643,7 @@ void GBAMemoryUpdateDMAs(struct GBA* gba, int32_t cycles) {
void GBAMemoryServiceDMA(struct GBA* gba, int number, struct GBADMA* info) {
struct GBAMemory* memory = &gba->memory;
struct ARMCore* cpu = gba->cpu;
uint32_t width = GBADMARegisterGetWidth(info->reg) ? 4 : 2;
int sourceOffset = DMA_OFFSET[GBADMARegisterGetSrcControl(info->reg)] * width;
int destOffset = DMA_OFFSET[GBADMARegisterGetDestControl(info->reg)] * width;
uint32_t width = 2 << GBADMARegisterGetWidth(info->reg);
int32_t wordsRemaining = info->nextCount;
uint32_t source = info->nextSource;
uint32_t dest = info->nextDest;
@ -1660,8 +1658,6 @@ void GBAMemoryServiceDMA(struct GBA* gba, int number, struct GBADMA* info) {
}
if (width == 4) {
cycles += memory->waitstatesNonseq32[sourceRegion] + memory->waitstatesNonseq32[destRegion];
source &= 0xFFFFFFFC;
dest &= 0xFFFFFFFC;
} else {
cycles += memory->waitstatesNonseq16[sourceRegion] + memory->waitstatesNonseq16[destRegion];
}
@ -1672,6 +1668,8 @@ void GBAMemoryServiceDMA(struct GBA* gba, int number, struct GBADMA* info) {
return;
}
info->hasStarted = 2;
source &= -width;
dest &= -width;
} else {
if (width == 4) {
cycles += memory->waitstatesSeq32[sourceRegion] + memory->waitstatesSeq32[destRegion];
@ -1679,44 +1677,36 @@ void GBAMemoryServiceDMA(struct GBA* gba, int number, struct GBADMA* info) {
cycles += memory->waitstatesSeq16[sourceRegion] + memory->waitstatesSeq16[destRegion];
}
}
info->nextEvent += cycles;
gba->performingDMA = 1 | (number << 1);
int32_t word;
uint32_t word;
if (width == 4) {
word = cpu->memory.load32(cpu, source, 0);
gba->bus = word;
cpu->memory.store32(cpu, dest, word, 0);
source += sourceOffset;
dest += destOffset;
--wordsRemaining;
} else {
if (sourceRegion == REGION_CART2_EX && memory->savedata.type == SAVEDATA_EEPROM) {
word = GBASavedataReadEEPROM(&memory->savedata);
gba->bus = word | (word << 16);
cpu->memory.store16(cpu, dest, word, 0);
source += sourceOffset;
dest += destOffset;
--wordsRemaining;
} else if (destRegion == REGION_CART2_EX) {
if (memory->savedata.type == SAVEDATA_AUTODETECT) {
mLOG(GBA_MEM, INFO, "Detected EEPROM savegame");
GBASavedataInitEEPROM(&memory->savedata, gba->realisticTiming);
}
word = cpu->memory.load16(cpu, source, 0);
gba->bus = word | (word << 16);
GBASavedataWriteEEPROM(&memory->savedata, word, wordsRemaining);
source += sourceOffset;
dest += destOffset;
--wordsRemaining;
} else {
word = cpu->memory.load16(cpu, source, 0);
gba->bus = word | (word << 16);
cpu->memory.store16(cpu, dest, word, 0);
source += sourceOffset;
dest += destOffset;
--wordsRemaining;
}
gba->bus = word | (word << 16);
}
int sourceOffset = DMA_OFFSET[GBADMARegisterGetSrcControl(info->reg)] * width;
int destOffset = DMA_OFFSET[GBADMARegisterGetDestControl(info->reg)] * width;
source += sourceOffset;
dest += destOffset;
--wordsRemaining;
gba->performingDMA = 0;
if (!wordsRemaining) {
@ -1741,10 +1731,6 @@ void GBAMemoryServiceDMA(struct GBA* gba, int number, struct GBADMA* info) {
info->nextCount = wordsRemaining;
}
info->nextSource = source;
if (info->nextEvent != INT_MAX) {
info->nextEvent += cycles;
}
GBAMemoryUpdateDMAs(gba, 0);
}