DMA: Restrict $2080<->WRAM DMA behavior based on tests

Core/DebugTypes.h

@@ -18,6 +18,7 @@ enum class SnesMemoryType
 	VideoRam,
 	SpriteRam,
 	CGRam,
+	Register
 };
 
 struct AddressInfo

Core/DmaController.cpp

@@ -8,6 +8,28 @@ DmaController::DmaController(MemoryManager *memoryManager)
 	_memoryManager = memoryManager;
 }
 
+void DmaController::CopyDmaByte(uint32_t addressBusA, uint16_t addressBusB, bool fromBtoA)
+{
+	if(fromBtoA) {
+		if(addressBusB != 0x2180 || !_memoryManager->IsWorkRam(addressBusA)) {
+			uint8_t valToWrite = _memoryManager->ReadDma(addressBusB);
+			_memoryManager->WriteDma(addressBusA, valToWrite);
+		} else {
+			//$2180->WRAM do cause a write to occur (but no read), but the value written is invalid
+			_memoryManager->IncrementMasterClockValue<4>();
+			_memoryManager->WriteDma(addressBusA, 0xFF);
+		}
+	} else {
+		if(addressBusB != 0x2180 || !_memoryManager->IsWorkRam(addressBusA)) {
+			uint8_t valToWrite = _memoryManager->ReadDma(addressBusA);
+			_memoryManager->WriteDma(addressBusB, valToWrite);
+		} else {
+			//WRAM->$2180 does not cause a write to occur
+			_memoryManager->IncrementMasterClockValue<8>();
+		}
+	}
+}
+
 void DmaController::RunSingleTransfer(DmaChannelConfig &channel)
 {
 	const uint8_t *transferOffsets = _transferOffset[channel.TransferMode];
@@ -15,13 +37,11 @@ void DmaController::RunSingleTransfer(DmaChannelConfig &channel)
 
 	uint8_t i = 0;
 	do {
-		if(channel.InvertDirection) {
+		CopyDmaByte(
-			uint8_t valToWrite = _memoryManager->ReadDma(0x2100 | channel.DestAddress + transferOffsets[i]);
+			(channel.SrcBank << 16) | channel.SrcAddress,
-			_memoryManager->WriteDma((channel.SrcBank << 16) | channel.SrcAddress, valToWrite);
+			0x2100 | channel.DestAddress + transferOffsets[i],
-		} else {
+			channel.InvertDirection
-			uint8_t valToWrite = _memoryManager->ReadDma((channel.SrcBank << 16) | channel.SrcAddress);
+		);
-			_memoryManager->WriteDma(0x2100 | channel.DestAddress + transferOffsets[i], valToWrite);
-		}
 
 		if(!channel.FixedTransfer) {
 			channel.SrcAddress += channel.Decrement ? -1 : 1;
@@ -105,13 +125,11 @@ void DmaController::RunHdmaTransfer(DmaChannelConfig &channel)
 
 	uint8_t i = 0;
 	do {
-		if(channel.InvertDirection) {
+		CopyDmaByte(
-			uint8_t valToWrite = _memoryManager->ReadDma(0x2100 | channel.DestAddress + transferOffsets[i]);
+			srcAddress,
-			_memoryManager->WriteDma(srcAddress, valToWrite);
+			0x2100 | channel.DestAddress + transferOffsets[i],
-		} else {
+			channel.InvertDirection
-			uint8_t valToWrite = _memoryManager->ReadDma(srcAddress);
+		);
-			_memoryManager->WriteDma(0x2100 | channel.DestAddress + transferOffsets[i], valToWrite);
-		}
 
 		srcAddress = (srcAddress + (channel.Decrement ? -1 : 1)) & 0xFFFFFF;
 

Core/DmaController.h

@@ -43,13 +43,15 @@ private:
 	DmaChannelConfig _channel[8] = {};
 	MemoryManager *_memoryManager;
 	
+	void CopyDmaByte(uint32_t addressBusA, uint16_t addressBusB, bool fromBtoA);
+
 	void RunSingleTransfer(DmaChannelConfig &channel);
 	void RunDma(DmaChannelConfig &channel);
 	void RunHdmaTransfer(DmaChannelConfig &channel);
 	
 public:
 	DmaController(MemoryManager *memoryManager);
-	
+
 	void InitHdmaChannels();
 	void ProcessHdmaChannels();
 

Core/IMemoryHandler.h

@@ -4,11 +4,19 @@
 
 class IMemoryHandler
 {
+protected:
+	SnesMemoryType _memoryType;
+
 public:
 	virtual uint8_t Read(uint32_t addr) = 0;
 	virtual uint8_t Peek(uint32_t addr) = 0;
 	virtual void Write(uint32_t addr, uint8_t value) = 0;
 
+	__forceinline SnesMemoryType GetMemoryType()
+	{
+		return _memoryType;
+	}
+
 	virtual AddressInfo GetAbsoluteAddress(uint32_t address) = 0;
 
 	//virtual void GetMemoryRanges(MemoryRanges &ranges) = 0;

Core/MemoryManager.cpp

@@ -248,6 +248,12 @@ bool MemoryManager::IsRegister(uint32_t cpuAddress)
 	return _handlers[cpuAddress >> 12] == _registerHandlerA.get() || _handlers[cpuAddress >> 12] == _registerHandlerB.get();
 }
 
+bool MemoryManager::IsWorkRam(uint32_t cpuAddress)
+{
+	IMemoryHandler* handler = _handlers[cpuAddress >> 12];
+	return handler && handler->GetMemoryType() == SnesMemoryType::WorkRam;
+}
+
 AddressInfo MemoryManager::GetAbsoluteAddress(uint32_t addr)
 {
 	if(_handlers[addr >> 12]) {

Core/MemoryManager.h

@@ -62,6 +62,7 @@ public:
 	uint8_t* DebugGetWorkRam();
 
 	bool IsRegister(uint32_t cpuAddress);
+	bool IsWorkRam(uint32_t cpuAddress);
 	AddressInfo GetAbsoluteAddress(uint32_t addr);
 	int GetRelativeAddress(AddressInfo &address, int32_t cpuAddress = -1);
 };

Core/RamHandler.h

@@ -9,7 +9,6 @@ private:
 	uint8_t * _ram;
 	uint32_t _offset;
 	uint32_t _mask;
-	SnesMemoryType _memoryType;
 
 public:
 	RamHandler(uint8_t *ram, uint32_t offset, uint32_t size, SnesMemoryType memoryType)

Core/RegisterHandlerA.h

@@ -18,6 +18,7 @@ public:
 		_regs = regs;
 		_dmaController = dmaController;
 		_controlManager = controlManager;
+		_memoryType = SnesMemoryType::Register;
 	}
 
 	uint8_t Read(uint32_t addr) override

Core/RegisterHandlerB.h

@@ -22,6 +22,7 @@ public:
 		_spc = spc;
 		_workRam = workRam;
 		_wramPosition = 0;
+		_memoryType = SnesMemoryType::Register;
 	}
 
 	uint8_t Read(uint32_t addr) override