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GBA DMA: Emulate DMA bus

This commit is contained in:
Jeffrey Pfau 2014-11-02 16:54:11 -08:00
parent 2ff5809252
commit 8b6a76142a
3 changed files with 29 additions and 7 deletions
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29
src/gba/gba-memory.c
View File

@ -209,9 +209,13 @@ static void GBASetActiveRegion(struct ARMCore* cpu, uint32_t address) {
#define LOAD_BAD \
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load32: 0x%08X", address); \
value = cpu->prefetch; \
if (cpu->executionMode == MODE_THUMB) { \
value |= value << 16; \
if (cpu->cycles >= cpu->nextEvent) { \
value = gba->bus; \
} else { \
value = cpu->prefetch; \
if (cpu->executionMode == MODE_THUMB) { \
value |= value << 16; \
} \
}
int32_t GBALoad32(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
@ -339,7 +343,11 @@ int16_t GBALoad16(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
break;
default:
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load16: 0x%08X", address);
value = cpu->prefetch;
if (cpu->cycles >= cpu->nextEvent) {
value = gba->bus;
} else {
value = cpu->prefetch;
}
break;
}
@ -424,7 +432,11 @@ int8_t GBALoad8(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
break;
default:
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load8: 0x%08x", address);
value = cpu->prefetch & 0xFF;
if (cpu->cycles >= cpu->nextEvent) {
value = gba->bus;
} else {
value = cpu->prefetch;
}
break;
}
@ -1096,17 +1108,18 @@ void GBAMemoryServiceDMA(struct GBA* gba, int number, struct GBADMA* info) {
}
}
int32_t word;
if (width == 4) {
int32_t word;
word = cpu->memory.load32(cpu, source, 0);
gba->bus = word;
cpu->memory.store32(cpu, dest, word, 0);
source += sourceOffset;
dest += destOffset;
--wordsRemaining;
} else {
uint16_t word;
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;
@ -1117,12 +1130,14 @@ void GBAMemoryServiceDMA(struct GBA* gba, int number, struct GBADMA* info) {
GBASavedataInitEEPROM(&memory->savedata);
}
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;

5
src/gba/gba.c
View File

@ -210,6 +210,11 @@ static void GBAProcessEvents(struct ARMCore* cpu) {
int32_t nextEvent = INT_MAX;
int32_t testEvent;
gba->bus = cpu->prefetch;
if (cpu->executionMode == MODE_THUMB) {
gba->bus |= cpu->prefetch << 16;
}
if (gba->springIRQ) {
ARMRaiseIRQ(cpu);
gba->springIRQ = 0;

2
src/gba/gba.h
View File

@ -94,6 +94,8 @@ struct GBA {
struct ARMDebugger* debugger;
uint32_t bus;
int timersEnabled;
struct GBATimer timers[4];