ShuriZma
/
mgba
mirror of https://github.com/mgba-emu/mgba.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

GB Memory: Add GDMAs

This commit is contained in:
Jeffrey Pfau 2016-02-16 23:00:24 -08:00
parent d7d8dacaa8
commit 9d209aa9bb
3 changed files with 76 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
src/gb/io.c
View File

@ -311,6 +311,16 @@ void GBIOWrite(struct GB* gb, unsigned address, uint8_t value) {
case REG_VBK:
GBVideoSwitchBank(&gb->video, value);
break;
case REG_HDMA1:
case REG_HDMA2:
case REG_HDMA3:
case REG_HDMA4:
// Handled transparently by the registers
break;
case REG_HDMA5:
GBMemoryWriteHDMA5(gb, value);
value &= 0x7F;
break;
case REG_BCPS:
gb->video.bcpIndex = value & 0x3F;
gb->video.bcpIncrement = value & 0x80;
@ -436,8 +446,13 @@ uint8_t GBIORead(struct GB* gb, unsigned address) {
default:
if (gb->model >= GB_MODEL_CGB) {
switch (address) {
case REG_SVBK:
case REG_VBK:
case REG_HDMA1:
case REG_HDMA2:
case REG_HDMA3:
case REG_HDMA4:
case REG_HDMA5:
case REG_SVBK:
// Handled transparently by the registers
goto success;
default:

60
src/gb/memory.c
View File

@ -36,7 +36,7 @@ static void GBSetActiveRegion(struct LR35902Core* cpu, uint16_t address) {
}
static void _GBMemoryDMAService(struct GB* gb);
static void _GBMemoryHDMAService(struct GB* gb);
void GBMemoryInit(struct GB* gb) {
struct LR35902Core* cpu = gb->cpu;
@ -56,6 +56,8 @@ void GBMemoryInit(struct GB* gb) {
gb->memory.dmaNext = INT_MAX;
gb->memory.dmaRemaining = 0;
gb->memory.hdmaNext = INT_MAX;
gb->memory.hdmaRemaining = 0;
memset(gb->memory.hram, 0, sizeof(gb->memory.hram));
@ -257,14 +259,24 @@ void GBStore8(struct LR35902Core* cpu, uint16_t address, int8_t value) {
}
int32_t GBMemoryProcessEvents(struct GB* gb, int32_t cycles) {
if (!gb->memory.dmaRemaining) {
return INT_MAX;
int nextEvent = INT_MAX;
if (gb->memory.dmaRemaining) {
gb->memory.dmaNext -= cycles;
if (gb->memory.dmaNext <= 0) {
_GBMemoryDMAService(gb);
}
nextEvent = gb->memory.dmaNext;
}
gb->memory.dmaNext -= cycles;
if (gb->memory.dmaNext <= 0) {
_GBMemoryDMAService(gb);
if (gb->memory.hdmaRemaining) {
gb->memory.hdmaNext -= cycles;
if (gb->memory.hdmaNext <= 0) {
_GBMemoryHDMAService(gb);
}
if (gb->memory.hdmaNext < nextEvent) {
nextEvent = gb->memory.hdmaNext;
}
}
return gb->memory.dmaNext;
return nextEvent;
}
void GBMemoryDMA(struct GB* gb, uint16_t base) {
@ -282,6 +294,26 @@ void GBMemoryDMA(struct GB* gb, uint16_t base) {
gb->memory.dmaRemaining = 0xA0;
}
void GBMemoryWriteHDMA5(struct GB* gb, uint8_t value) {
gb->memory.hdmaSource = gb->memory.io[REG_HDMA1] << 8;
gb->memory.hdmaSource |= gb->memory.io[REG_HDMA2];
gb->memory.hdmaDest = gb->memory.io[REG_HDMA3] << 8;
gb->memory.hdmaDest |= gb->memory.io[REG_HDMA4];
gb->memory.hdmaSource &= 0xFFF0;
if (gb->memory.hdmaSource >= 0x8000 && gb->memory.hdmaSource < 0xA000) {
mLOG(GB_MEM, GAME_ERROR, "Invalid HDMA source: %04X", gb->memory.hdmaSource);
return;
}
gb->memory.hdmaDest &= 0x1FF0;
gb->memory.hdmaDest |= 0x8000;
gb->memory.isHdma = value & 0x80;
if (!gb->memory.isHdma) {
gb->memory.hdmaRemaining = ((value & 0x7F) + 1) * 0x10;
gb->memory.hdmaNext = gb->cpu->cycles;
gb->cpu->nextEvent = gb->cpu->cycles;
}
}
void _GBMemoryDMAService(struct GB* gb) {
uint8_t b = GBLoad8(gb->cpu, gb->memory.dmaSource);
// TODO: Can DMA write OAM during modes 2-3?
@ -298,6 +330,20 @@ void _GBMemoryDMAService(struct GB* gb) {
}
}
void _GBMemoryHDMAService(struct GB* gb) {
uint8_t b = gb->cpu->memory.load8(gb->cpu, gb->memory.hdmaSource);
gb->cpu->memory.store8(gb->cpu, gb->memory.hdmaDest, b);
++gb->memory.hdmaSource;
++gb->memory.hdmaDest;
--gb->memory.hdmaRemaining;
gb->cpu->cycles += 2;
if (gb->memory.hdmaRemaining) {
gb->memory.hdmaNext += 2;
} else {
gb->memory.io[REG_HDMA5] |= 0x80;
}
}
uint8_t GBDMALoad8(struct LR35902Core* cpu, uint16_t address) {
struct GB* gb = (struct GB*) cpu->master;
struct GBMemory* memory = &gb->memory;

7
src/gb/memory.h
View File

@ -97,6 +97,12 @@ struct GBMemory {
uint16_t dmaDest;
int dmaRemaining;
int32_t hdmaNext;
uint16_t hdmaSource;
uint16_t hdmaDest;
int hdmaRemaining;
bool isHdma;
size_t romSize;
bool rtcAccess;
@ -117,6 +123,7 @@ void GBStore8(struct LR35902Core* cpu, uint16_t address, int8_t value);
int32_t GBMemoryProcessEvents(struct GB* gb, int32_t cycles);
void GBMemoryDMA(struct GB* gb, uint16_t base);
void GBMemoryWriteHDMA5(struct GB* gb, uint8_t value);
uint8_t GBDMALoad8(struct LR35902Core* cpu, uint16_t address);
void GBDMAStore8(struct LR35902Core* cpu, uint16_t address, int8_t value);