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GBA Memory: Improve Thumb open bus behavior (fixes issue #10)

This commit is contained in:
Jeffrey Pfau 2015-04-17 03:20:09 -07:00
parent 592f6614aa
commit 02ecfa6843
2 changed files with 41 additions and 46 deletions
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1
CHANGES
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@ -25,6 +25,7 @@ Bugfixes:
- Qt: Fix potential crash if a gamepad causes focus to change
- GBA Memory: Allow SRAM to be 64kB
- Qt: Fix controller axis querying
- GBA Memory: Improve Thumb open bus behavior
Misc:
- Qt: Show multiplayer numbers in window title

84
src/gba/memory.c
View File

@ -279,14 +279,31 @@ static void GBASetActiveRegion(struct ARMCore* cpu, uint32_t address) {
}
#define LOAD_BAD \
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load32: 0x%08X", address); \
if (gba->performingDMA) { \
value = gba->bus; \
} else { \
value = cpu->prefetch[1]; \
if (cpu->executionMode == MODE_THUMB) { \
/* http://ngemu.com/threads/gba-open-bus.170809/ */ \
switch (cpu->gprs[ARM_PC] >> BASE_OFFSET) { \
case REGION_BIOS: \
case REGION_OAM: \
/* This isn't right half the time, but we don't have $+6 handy */ \
value <<= 16; \
value |= cpu->prefetch[0]; \
break; \
case REGION_WORKING_IRAM: \
/* This doesn't handle prefetch clobbering */ \
if (cpu->gprs[ARM_PC] & 2) { \
value |= cpu->prefetch[0] << 16; \
} else { \
value <<= 16; \
value |= cpu->prefetch[0]; \
} \
default: \
value |= value << 16; \
} \
} \
}
#define LOAD_BIOS \
@ -298,6 +315,7 @@ static void GBASetActiveRegion(struct ARMCore* cpu, uint32_t address) {
value = memory->biosPrefetch; \
} \
} else { \
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load32: 0x%08X", address); \
LOAD_BAD; \
}
@ -380,6 +398,7 @@ uint32_t GBALoad32(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
LOAD_SRAM;
break;
default:
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load32: 0x%08X", address);
LOAD_BAD;
break;
}
@ -409,15 +428,9 @@ uint32_t GBALoad16(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
}
} else {
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load16: 0x%08X", address);
if (gba->performingDMA) {
LOAD_16(value, address & 2, &gba->bus);
} else {
uint32_t prefetch = cpu->prefetch[1];
if (cpu->executionMode == MODE_THUMB) {
prefetch |= prefetch << 16;
}
LOAD_16(value, address & 2, &prefetch);
}
LOAD_BAD;
uint32_t v2 = value;
LOAD_16(v2, address & 2, &value);
}
break;
case REGION_WORKING_RAM:
@ -475,15 +488,9 @@ uint32_t GBALoad16(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
break;
default:
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load16: 0x%08X", address);
if (gba->performingDMA) {
LOAD_16(value, address & 2, &gba->bus);
} else {
uint32_t prefetch = cpu->prefetch[1];
if (cpu->executionMode == MODE_THUMB) {
prefetch |= prefetch << 16;
}
LOAD_16(value, address & 2, &prefetch);
}
LOAD_BAD;
uint32_t v2 = value;
LOAD_16(v2, address & 2, &value);
break;
}
@ -498,49 +505,42 @@ uint32_t GBALoad16(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
uint32_t GBALoad8(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
struct GBA* gba = (struct GBA*) cpu->master;
struct GBAMemory* memory = &gba->memory;
uint8_t value = 0;
uint32_t value = 0;
int wait = 0;
switch (address >> BASE_OFFSET) {
case REGION_BIOS:
if (address < SIZE_BIOS) {
if (memory->activeRegion == REGION_BIOS) {
value = ((int8_t*) memory->bios)[address];
value = ((uint8_t*) memory->bios)[address];
} else {
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad BIOS Load8: 0x%08X", address);
value = ((uint8_t*) &memory->biosPrefetch)[address & 3];
}
} else {
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load8: 0x%08x", address);
if (gba->performingDMA) {
value = ((uint8_t*) &gba->bus)[address & 3];
} else {
uint32_t prefetch = cpu->prefetch[1];
if (cpu->executionMode == MODE_THUMB) {
prefetch |= prefetch << 16;
}
value = ((uint8_t*) &prefetch)[address & 3];
}
LOAD_BAD;
value = ((uint8_t*) &value)[address & 3];
}
break;
case REGION_WORKING_RAM:
value = ((int8_t*) memory->wram)[address & (SIZE_WORKING_RAM - 1)];
value = ((uint8_t*) memory->wram)[address & (SIZE_WORKING_RAM - 1)];
wait = memory->waitstatesNonseq16[REGION_WORKING_RAM];
break;
case REGION_WORKING_IRAM:
value = ((int8_t*) memory->iwram)[address & (SIZE_WORKING_IRAM - 1)];
value = ((uint8_t*) memory->iwram)[address & (SIZE_WORKING_IRAM - 1)];
break;
case REGION_IO:
value = (GBAIORead(gba, address & 0xFFFE) >> ((address & 0x0001) << 3)) & 0xFF;
break;
case REGION_PALETTE_RAM:
value = ((int8_t*) gba->video.palette)[address & (SIZE_PALETTE_RAM - 1)];
value = ((uint8_t*) gba->video.palette)[address & (SIZE_PALETTE_RAM - 1)];
break;
case REGION_VRAM:
if ((address & 0x0001FFFF) < SIZE_VRAM) {
value = ((int8_t*) gba->video.renderer->vram)[address & 0x0001FFFF];
value = ((uint8_t*) gba->video.renderer->vram)[address & 0x0001FFFF];
} else {
value = ((int8_t*) gba->video.renderer->vram)[address & 0x00017FFF];
value = ((uint8_t*) gba->video.renderer->vram)[address & 0x00017FFF];
}
break;
case REGION_OAM:
@ -554,7 +554,7 @@ uint32_t GBALoad8(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
case REGION_CART2_EX:
wait = memory->waitstatesNonseq16[address >> BASE_OFFSET];
if ((address & (SIZE_CART0 - 1)) < memory->romSize) {
value = ((int8_t*) memory->rom)[address & (SIZE_CART0 - 1)];
value = ((uint8_t*) memory->rom)[address & (SIZE_CART0 - 1)];
} else {
GBALog(gba, GBA_LOG_GAME_ERROR, "Out of bounds ROM Load8: 0x%08X", address);
value = (address >> 1) & 0xFF; \
@ -577,18 +577,12 @@ uint32_t GBALoad8(struct ARMCore* cpu, uint32_t address, int* cycleCounter) {
GBALog(gba, GBA_LOG_GAME_ERROR, "Reading from non-existent SRAM: 0x%08X", address);
value = 0xFF;
}
value &= 0xFF;
break;
default:
GBALog(gba, GBA_LOG_GAME_ERROR, "Bad memory Load8: 0x%08x", address);
if (gba->performingDMA) {
value = ((uint8_t*) &gba->bus)[address & 3];
} else {
uint32_t prefetch = cpu->prefetch[1];
if (cpu->executionMode == MODE_THUMB) {
prefetch |= prefetch << 16;
}
value = ((uint8_t*) &prefetch)[address & 3];
}
LOAD_BAD;
value = ((uint8_t*) &value)[address & 3];
break;
}