Run ahead support (+ improved save/load state performance)

Note: Run ahead currently doesn't work well with netplay, movies and rewind

Core/Console.cpp

@@ -90,6 +90,14 @@ void Console::Release()
 	_movieManager.reset();
 }
 
+void Console::RunFrame()
+{
+	uint32_t frameCount = _ppu->GetFrameCount();
+	while(frameCount == _ppu->GetFrameCount()) {
+		_cpu->Exec();
+	}
+}
+
 void Console::Run()
 {
 	if(!_cpu) {
@@ -98,9 +106,9 @@ void Console::Run()
 	
 	auto emulationLock = _emulationLock.AcquireSafe();
 	auto lock = _runLock.AcquireSafe();
-	uint32_t previousFrameCount = 0;
 
 	_stopFlag = false;
+	_isRunAheadFrame = false;
 
 	PlatformUtilities::EnableHighResolutionTimer();
 
@@ -116,29 +124,25 @@ void Console::Run()
 	_lastFrameTimer.Reset();
 
 	while(!_stopFlag) {
-		_cpu->Exec();
+		bool useRunAhead = _settings->GetEmulationConfig().RunAheadFrames > 0 && !_debugger && !_rewindManager->IsRewinding() && _settings->GetEmulationSpeed() > 0 && _settings->GetEmulationSpeed() <= 100;
-
+		if(useRunAhead) {
-		if(previousFrameCount != _ppu->GetFrameCount()) {
+			RunFrameWithRunAhead();
+		} else {
+			RunFrame();
 			_rewindManager->ProcessEndOfFrame();
-
+			ProcessSystemActions();
-			WaitForLock();
-
-			if(_pauseOnNextFrame) {
-				_pauseOnNextFrame = false;
-				_paused = true;
-			}
-
-			if(_paused && !_stopFlag && !_debugger) {
-				WaitForPauseEnd();
-			}
-			previousFrameCount = _ppu->GetFrameCount();
-
-			if(_controlManager->GetSystemActionManager()->IsResetPressed()) {
-				Reset();
-			} else if(_controlManager->GetSystemActionManager()->IsPowerCyclePressed()) {
-				PowerCycle();
-			}
 		}
+
+		WaitForLock();
+
+		if(_pauseOnNextFrame) {
+			_pauseOnNextFrame = false;
+			_paused = true;
+		}
+
+		if(_paused && !_stopFlag && !_debugger) {
+			WaitForPauseEnd();
+		}		
 	}
 
 	_movieManager->Stop();
@@ -148,6 +152,48 @@ void Console::Run()
 	PlatformUtilities::RestoreTimerResolution();
 }
 
+bool Console::ProcessSystemActions()
+{
+	if(_controlManager->GetSystemActionManager()->IsResetPressed()) {
+		Reset();
+		return true;
+	} else if(_controlManager->GetSystemActionManager()->IsPowerCyclePressed()) {
+		PowerCycle();
+		return true;
+	}
+	return false;
+}
+
+void Console::RunFrameWithRunAhead()
+{
+	stringstream runAheadState;
+	uint32_t frameCount = _settings->GetEmulationConfig().RunAheadFrames;
+
+	//Run a single frame and save the state (no audio/video)
+	_isRunAheadFrame = true;
+	RunFrame();
+	Serialize(runAheadState, 0);
+
+	while(frameCount > 1) {
+		//Run extra frames if the requested run ahead frame count is higher than 1
+		frameCount--;
+		RunFrame();
+	}
+	_isRunAheadFrame = false;
+
+	//Run one frame normally (with audio/video output)
+	RunFrame();
+	_rewindManager->ProcessEndOfFrame();
+	
+	bool wasReset = ProcessSystemActions();
+	if(!wasReset) {
+		//Load the state we saved earlier
+		_isRunAheadFrame = true;
+		Deserialize(runAheadState, SaveStateManager::FileFormatVersion, false);
+		_isRunAheadFrame = false;
+	}
+}
+
 void Console::ProcessEndOfFrame()
 {
 #ifndef LIBRETRO
@@ -156,25 +202,27 @@ void Console::ProcessEndOfFrame()
 		_cart->GetCoprocessor()->ProcessEndOfFrame();
 	}
 
-	_frameLimiter->ProcessFrame();
+	if(!_isRunAheadFrame) {
-	while(_frameLimiter->WaitForNextFrame()) {
+		_frameLimiter->ProcessFrame();
-		if(_stopFlag || _frameDelay != GetFrameDelay() || _paused || _pauseOnNextFrame || _lockCounter > 0) {
+		while(_frameLimiter->WaitForNextFrame()) {
-			//Need to process another event, stop sleeping
+			if(_stopFlag || _frameDelay != GetFrameDelay() || _paused || _pauseOnNextFrame || _lockCounter > 0) {
-			break;
+				//Need to process another event, stop sleeping
+				break;
+			}
 		}
-	}
 
-	double newFrameDelay = GetFrameDelay();
+		double newFrameDelay = GetFrameDelay();
-	if(newFrameDelay != _frameDelay) {
+		if(newFrameDelay != _frameDelay) {
-		_frameDelay = newFrameDelay;
+			_frameDelay = newFrameDelay;
-		_frameLimiter->SetDelay(_frameDelay);
+			_frameLimiter->SetDelay(_frameDelay);
-	}
+		}
 
-	PreferencesConfig cfg = _settings->GetPreferences();
+		PreferencesConfig cfg = _settings->GetPreferences();
-	if(cfg.ShowDebugInfo) {
+		if(cfg.ShowDebugInfo) {
-		double lastFrameTime = _lastFrameTimer.GetElapsedMS();
+			double lastFrameTime = _lastFrameTimer.GetElapsedMS();
-		_lastFrameTimer.Reset();
+			_lastFrameTimer.Reset();
-		_stats->DisplayStats(this, lastFrameTime);
+			_stats->DisplayStats(this, lastFrameTime);
+		}
 	}
 
 	_controlManager->UpdateInputState();
@@ -554,7 +602,7 @@ void Console::WaitForLock()
 	}
 }
 
-void Console::Serialize(ostream &out)
+void Console::Serialize(ostream &out, int compressionLevel)
 {
 	Serializer serializer(SaveStateManager::FileFormatVersion);
 	serializer.Stream(_cpu.get());
@@ -568,12 +616,12 @@ void Console::Serialize(ostream &out)
 	if(_msu1) {
 		serializer.Stream(_msu1.get());
 	}
-	serializer.Save(out);
+	serializer.Save(out, compressionLevel);
 }
 
-void Console::Deserialize(istream &in, uint32_t fileFormatVersion)
+void Console::Deserialize(istream &in, uint32_t fileFormatVersion, bool compressed)
 {
-	Serializer serializer(in, fileFormatVersion);
+	Serializer serializer(in, fileFormatVersion, compressed);
 	serializer.Stream(_cpu.get());
 	serializer.Stream(_memoryManager.get());
 	serializer.Stream(_ppu.get());
@@ -731,6 +779,11 @@ bool Console::IsRunning()
 	return _cpu != nullptr;
 }
 
+bool Console::IsRunAheadFrame()
+{
+	return _isRunAheadFrame;
+}
+
 template<CpuType type>
 void Console::ProcessMemoryRead(uint32_t addr, uint8_t value, MemoryOperationType opType)
 {

Core/Console.h

@@ -82,6 +82,8 @@ private:
 	ConsoleRegion _region;
 	uint32_t _masterClockRate;
 
+	atomic<bool> _isRunAheadFrame;
+
 	unique_ptr<DebugStats> _stats;
 	unique_ptr<FrameLimiter> _frameLimiter;
 	Timer _lastFrameTimer;
@@ -92,6 +94,10 @@ private:
 	void WaitForLock();
 	void WaitForPauseEnd();
 
+	void RunFrame();
+	bool ProcessSystemActions();
+	void RunFrameWithRunAhead();
+
 public:
 	Console();
 	~Console();
@@ -99,6 +105,7 @@ public:
 	void Initialize();
 	void Release();
 
+
 	void Run();
 	void RunSingleFrame();
 	void Stop(bool sendNotification);
@@ -123,8 +130,8 @@ public:
 	void Lock();
 	void Unlock();
 
-	void Serialize(ostream &out);
+	void Serialize(ostream &out, int compressionLevel = 1);
-	void Deserialize(istream &in, uint32_t fileFormatVersion);
+	void Deserialize(istream &in, uint32_t fileFormatVersion, bool compressed = true);
 
 	shared_ptr<SoundMixer> GetSoundMixer();
 	shared_ptr<VideoRenderer> GetVideoRenderer();
@@ -155,6 +162,8 @@ public:
 	thread::id GetEmulationThreadId();
 	
 	bool IsRunning();
+	bool IsInputRecordingEnabled();
+	bool IsRunAheadFrame();
 
 	template<CpuType type> void ProcessMemoryRead(uint32_t addr, uint8_t value, MemoryOperationType opType);
 	template<CpuType type> void ProcessMemoryWrite(uint32_t addr, uint8_t value, MemoryOperationType opType);

Core/ControlManager.cpp

@@ -163,8 +163,10 @@ void ControlManager::UpdateInputState()
 		debugger->ProcessEvent(EventType::InputPolled);
 	}
 
-	for(IInputRecorder* recorder : _inputRecorders) {
+	if(!_console->IsRunAheadFrame()) {
-		recorder->RecordInput(_controlDevices);
+		for(IInputRecorder* recorder : _inputRecorders) {
+			recorder->RecordInput(_controlDevices);
+		}
 	}
 
 	//MessageManager::Log(log);

Core/Ppu.cpp

@@ -476,6 +476,10 @@ bool Ppu::ProcessEndOfScanline(uint16_t hClock)
 				(_settings->GetEmulationSpeed() == 0 || _settings->GetEmulationSpeed() > 150) &&
 				_frameSkipTimer.GetElapsedMS() < 10
 			);
+			
+			if(_console->IsRunAheadFrame()) {
+				_skipRender = true;
+			}
 
 			//Update overclock timings once per frame
 			UpdateNmiScanline();

Core/RewindManager.cpp

@@ -44,6 +44,10 @@ void RewindManager::ClearBuffer()
 
 void RewindManager::ProcessNotification(ConsoleNotificationType type, void * parameter)
 {
+	if(_console->IsRunAheadFrame()) {
+		return;
+	}
+
 	if(type == ConsoleNotificationType::PpuFrameDone) {
 		_hasHistory = _history.size() >= 2;
 		if(_settings->GetRewindBufferSize() > 0) {

Core/SettingTypes.h

@@ -273,6 +273,8 @@ struct EmulationConfig
 
 	ConsoleRegion Region = ConsoleRegion::Auto;
 
+	uint32_t RunAheadFrames = 0;
+
 	bool EnableRandomPowerOnState = false;
 	bool EnableStrictBoardMappings = false;
 

Core/SoundMixer.cpp

@@ -93,7 +93,7 @@ void SoundMixer::PlayAudioBuffer(int16_t* samples, uint32_t sampleCount)
 	}
 
 	shared_ptr<RewindManager> rewindManager = _console->GetRewindManager();
-	if(rewindManager && rewindManager->SendAudio(out, count)) {
+	if(!_console->IsRunAheadFrame() && rewindManager && rewindManager->SendAudio(out, count)) {
 		bool isRecording = _waveRecorder || _console->GetVideoRenderer()->IsRecording();
 		if(isRecording) {
 			if(_waveRecorder) {

Core/SystemActionManager.h

@@ -41,11 +41,9 @@ public:
 	{
 		if(_needReset) {
 			SetBit(SystemActionManager::Buttons::ResetButton);
-			_needReset = false;
 		}
 		if(_needPowerCycle) {
 			SetBit(SystemActionManager::Buttons::PowerButton);
-			_needPowerCycle = false;
 		}
 	}
 
@@ -81,11 +79,13 @@ public:
 
 	bool IsResetPressed()
 	{
+		_needReset = false;
 		return IsPressed(SystemActionManager::Buttons::ResetButton);
 	}
 
 	bool IsPowerCyclePressed()
 	{
+		_needPowerCycle = false;
 		return IsPressed(SystemActionManager::Buttons::PowerButton);
 	}
 };

Core/VideoDecoder.cpp

@@ -158,6 +158,10 @@ uint32_t VideoDecoder::GetFrameCount()
 
 void VideoDecoder::UpdateFrameSync(uint16_t *ppuOutputBuffer, uint16_t width, uint16_t height, uint32_t frameNumber, bool forRewind)
 {
+	if(_console->IsRunAheadFrame()) {
+		return;
+	}
+
 	if(_frameChanged) {
 		//Last frame isn't done decoding yet - sometimes Signal() introduces a 25-30ms delay
 		while(_frameChanged) {
@@ -177,6 +181,10 @@ void VideoDecoder::UpdateFrameSync(uint16_t *ppuOutputBuffer, uint16_t width, ui
 
 void VideoDecoder::UpdateFrame(uint16_t *ppuOutputBuffer, uint16_t width, uint16_t height, uint32_t frameNumber)
 {
+	if(_console->IsRunAheadFrame()) {
+		return;
+	}
+
 	if(_frameChanged) {
 		//Last frame isn't done decoding yet - sometimes Signal() introduces a 25-30ms delay
 		while(_frameChanged) {

UI/Config/EmulationConfig.cs

@@ -15,6 +15,8 @@ namespace Mesen.GUI.Config
 		[MinMax(0, 5000)] public UInt32 RewindSpeed = 100;
 
 		public ConsoleRegion Region = ConsoleRegion.Auto;
+		
+		[MinMax(0, 10)] public UInt32 RunAheadFrames = 0;
 
 		[MarshalAs(UnmanagedType.I1)] public bool EnableRandomPowerOnState = false;
 		[MarshalAs(UnmanagedType.I1)] public bool EnableStrictBoardMappings = false;

UI/Dependencies/resources.en.xml

@@ -282,7 +282,9 @@
 			<Control ID="lblTurboSpeed">Fast Forward Speed:</Control>
 			<Control ID="lblRewindSpeedHint">%  (0 = Maximum speed)</Control>
 			<Control ID="lblRewindSpeed">Rewind Speed:</Control>
-
+			<Control ID="lblRunAhead">Run Ahead:</Control>
+			<Control ID="lblRunAheadFrames">frames (reduces input lag, increases CPU usage)</Control>
+			
 			<Control ID="tpgAdvanced">Advanced</Control>
 			<Control ID="lblDeveloperSettings">Recommended settings for developers (homebrew / ROM hacking)</Control>
 			<Control ID="lblMiscSettings">Miscellaneous Settings</Control>

UI/Forms/Config/frmEmulationConfig.Designer.cs

@@ -31,6 +31,10 @@
 			this.tabMain = new System.Windows.Forms.TabControl();
 			this.tpgGeneral = new System.Windows.Forms.TabPage();
 			this.tableLayoutPanel4 = new System.Windows.Forms.TableLayoutPanel();
+			this.flowLayoutPanel5 = new System.Windows.Forms.FlowLayoutPanel();
+			this.nudRunAheadFrames = new Mesen.GUI.Controls.MesenNumericUpDown();
+			this.lblRunAheadFrames = new System.Windows.Forms.Label();
+			this.lblRunAhead = new System.Windows.Forms.Label();
 			this.label1 = new System.Windows.Forms.Label();
 			this.flowLayoutPanel9 = new System.Windows.Forms.FlowLayoutPanel();
 			this.nudTurboSpeed = new Mesen.GUI.Controls.MesenNumericUpDown();
@@ -50,6 +54,7 @@
 			this.chkEnableRandomPowerOnState = new Mesen.GUI.Controls.ctrlRiskyOption();
 			this.cboRamPowerOnState = new System.Windows.Forms.ComboBox();
 			this.lblRamPowerOnState = new System.Windows.Forms.Label();
+			this.chkEnableStrictBoardMappings = new Mesen.GUI.Controls.ctrlRiskyOption();
 			this.tpgOverclocking = new System.Windows.Forms.TabPage();
 			this.picHint = new System.Windows.Forms.PictureBox();
 			this.tableLayoutPanel3 = new System.Windows.Forms.TableLayoutPanel();
@@ -63,10 +68,10 @@
 			this.tableLayoutPanel1 = new System.Windows.Forms.TableLayoutPanel();
 			this.nudGsuClockSpeed = new Mesen.GUI.Controls.MesenNumericUpDown();
 			this.lblGsuClockSpeed = new System.Windows.Forms.Label();
-			this.chkEnableStrictBoardMappings = new Mesen.GUI.Controls.ctrlRiskyOption();
 			this.tabMain.SuspendLayout();
 			this.tpgGeneral.SuspendLayout();
 			this.tableLayoutPanel4.SuspendLayout();
+			this.flowLayoutPanel5.SuspendLayout();
 			this.flowLayoutPanel9.SuspendLayout();
 			this.flowLayoutPanel6.SuspendLayout();
 			this.flowLayoutPanel10.SuspendLayout();
@@ -83,7 +88,7 @@
 			// baseConfigPanel
 			// 
 			this.baseConfigPanel.Location = new System.Drawing.Point(0, 290);
-			this.baseConfigPanel.Size = new System.Drawing.Size(414, 29);
+			this.baseConfigPanel.Size = new System.Drawing.Size(445, 29);
 			this.baseConfigPanel.TabIndex = 4;
 			// 
 			// tabMain
@@ -95,7 +100,7 @@
 			this.tabMain.Location = new System.Drawing.Point(0, 0);
 			this.tabMain.Name = "tabMain";
 			this.tabMain.SelectedIndex = 0;
-			this.tabMain.Size = new System.Drawing.Size(414, 290);
+			this.tabMain.Size = new System.Drawing.Size(445, 290);
 			this.tabMain.TabIndex = 2;
 			// 
 			// tpgGeneral
@@ -104,7 +109,7 @@
 			this.tpgGeneral.Location = new System.Drawing.Point(4, 22);
 			this.tpgGeneral.Name = "tpgGeneral";
 			this.tpgGeneral.Padding = new System.Windows.Forms.Padding(3);
-			this.tpgGeneral.Size = new System.Drawing.Size(406, 264);
+			this.tpgGeneral.Size = new System.Drawing.Size(437, 264);
 			this.tpgGeneral.TabIndex = 2;
 			this.tpgGeneral.Text = "General";
 			this.tpgGeneral.UseVisualStyleBackColor = true;
@@ -115,6 +120,8 @@
 			this.tableLayoutPanel4.ColumnCount = 2;
 			this.tableLayoutPanel4.ColumnStyles.Add(new System.Windows.Forms.ColumnStyle());
 			this.tableLayoutPanel4.ColumnStyles.Add(new System.Windows.Forms.ColumnStyle(System.Windows.Forms.SizeType.Percent, 100F));
+			this.tableLayoutPanel4.Controls.Add(this.flowLayoutPanel5, 1, 4);
+			this.tableLayoutPanel4.Controls.Add(this.lblRunAhead, 0, 4);
 			this.tableLayoutPanel4.Controls.Add(this.label1, 0, 3);
 			this.tableLayoutPanel4.Controls.Add(this.flowLayoutPanel9, 1, 1);
 			this.tableLayoutPanel4.Controls.Add(this.lblTurboSpeed, 0, 1);
@@ -126,15 +133,79 @@
 			this.tableLayoutPanel4.Dock = System.Windows.Forms.DockStyle.Fill;
 			this.tableLayoutPanel4.Location = new System.Drawing.Point(3, 3);
 			this.tableLayoutPanel4.Name = "tableLayoutPanel4";
-			this.tableLayoutPanel4.RowCount = 5;
+			this.tableLayoutPanel4.RowCount = 6;
+			this.tableLayoutPanel4.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel4.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel4.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel4.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel4.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel4.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Percent, 100F));
-			this.tableLayoutPanel4.Size = new System.Drawing.Size(400, 258);
+			this.tableLayoutPanel4.Size = new System.Drawing.Size(431, 258);
 			this.tableLayoutPanel4.TabIndex = 0;
 			// 
+			// flowLayoutPanel5
+			// 
+			this.flowLayoutPanel5.AutoSize = true;
+			this.flowLayoutPanel5.Controls.Add(this.nudRunAheadFrames);
+			this.flowLayoutPanel5.Controls.Add(this.lblRunAheadFrames);
+			this.flowLayoutPanel5.Dock = System.Windows.Forms.DockStyle.Fill;
+			this.flowLayoutPanel5.Location = new System.Drawing.Point(111, 108);
+			this.flowLayoutPanel5.Margin = new System.Windows.Forms.Padding(0);
+			this.flowLayoutPanel5.Name = "flowLayoutPanel5";
+			this.flowLayoutPanel5.Size = new System.Drawing.Size(320, 27);
+			this.flowLayoutPanel5.TabIndex = 20;
+			// 
+			// nudRunAheadFrames
+			// 
+			this.nudRunAheadFrames.DecimalPlaces = 0;
+			this.nudRunAheadFrames.Increment = new decimal(new int[] {
+            1,
+            0,
+            0,
+            0});
+			this.nudRunAheadFrames.IsHex = false;
+			this.nudRunAheadFrames.Location = new System.Drawing.Point(3, 3);
+			this.nudRunAheadFrames.Maximum = new decimal(new int[] {
+            10,
+            0,
+            0,
+            0});
+			this.nudRunAheadFrames.MaximumSize = new System.Drawing.Size(10000, 20);
+			this.nudRunAheadFrames.Minimum = new decimal(new int[] {
+            0,
+            0,
+            0,
+            0});
+			this.nudRunAheadFrames.MinimumSize = new System.Drawing.Size(0, 21);
+			this.nudRunAheadFrames.Name = "nudRunAheadFrames";
+			this.nudRunAheadFrames.Size = new System.Drawing.Size(48, 21);
+			this.nudRunAheadFrames.TabIndex = 1;
+			this.nudRunAheadFrames.Value = new decimal(new int[] {
+            0,
+            0,
+            0,
+            0});
+			// 
+			// lblRunAheadFrames
+			// 
+			this.lblRunAheadFrames.Anchor = System.Windows.Forms.AnchorStyles.Left;
+			this.lblRunAheadFrames.AutoSize = true;
+			this.lblRunAheadFrames.Location = new System.Drawing.Point(57, 7);
+			this.lblRunAheadFrames.Name = "lblRunAheadFrames";
+			this.lblRunAheadFrames.Size = new System.Drawing.Size(236, 13);
+			this.lblRunAheadFrames.TabIndex = 2;
+			this.lblRunAheadFrames.Text = "frames (reduces input lag, increases CPU usage)";
+			// 
+			// lblRunAhead
+			// 
+			this.lblRunAhead.Anchor = System.Windows.Forms.AnchorStyles.Left;
+			this.lblRunAhead.AutoSize = true;
+			this.lblRunAhead.Location = new System.Drawing.Point(3, 115);
+			this.lblRunAhead.Name = "lblRunAhead";
+			this.lblRunAhead.Size = new System.Drawing.Size(64, 13);
+			this.lblRunAhead.TabIndex = 19;
+			this.lblRunAhead.Text = "Run Ahead:";
+			// 
 			// label1
 			// 
 			this.label1.Anchor = System.Windows.Forms.AnchorStyles.Left;
@@ -154,7 +225,7 @@
 			this.flowLayoutPanel9.Location = new System.Drawing.Point(111, 27);
 			this.flowLayoutPanel9.Margin = new System.Windows.Forms.Padding(0);
 			this.flowLayoutPanel9.Name = "flowLayoutPanel9";
-			this.flowLayoutPanel9.Size = new System.Drawing.Size(289, 27);
+			this.flowLayoutPanel9.Size = new System.Drawing.Size(320, 27);
 			this.flowLayoutPanel9.TabIndex = 14;
 			// 
 			// nudTurboSpeed
@@ -217,7 +288,7 @@
 			this.flowLayoutPanel6.Location = new System.Drawing.Point(111, 0);
 			this.flowLayoutPanel6.Margin = new System.Windows.Forms.Padding(0);
 			this.flowLayoutPanel6.Name = "flowLayoutPanel6";
-			this.flowLayoutPanel6.Size = new System.Drawing.Size(289, 27);
+			this.flowLayoutPanel6.Size = new System.Drawing.Size(320, 27);
 			this.flowLayoutPanel6.TabIndex = 11;
 			// 
 			// nudEmulationSpeed
@@ -290,7 +361,7 @@
 			this.flowLayoutPanel10.Location = new System.Drawing.Point(111, 54);
 			this.flowLayoutPanel10.Margin = new System.Windows.Forms.Padding(0);
 			this.flowLayoutPanel10.Name = "flowLayoutPanel10";
-			this.flowLayoutPanel10.Size = new System.Drawing.Size(289, 27);
+			this.flowLayoutPanel10.Size = new System.Drawing.Size(320, 27);
 			this.flowLayoutPanel10.TabIndex = 16;
 			// 
 			// nudRewindSpeed
@@ -349,7 +420,7 @@
 			this.tpgAdvanced.Location = new System.Drawing.Point(4, 22);
 			this.tpgAdvanced.Name = "tpgAdvanced";
 			this.tpgAdvanced.Padding = new System.Windows.Forms.Padding(3);
-			this.tpgAdvanced.Size = new System.Drawing.Size(406, 264);
+			this.tpgAdvanced.Size = new System.Drawing.Size(437, 264);
 			this.tpgAdvanced.TabIndex = 3;
 			this.tpgAdvanced.Text = "Advanced";
 			this.tpgAdvanced.UseVisualStyleBackColor = true;
@@ -371,7 +442,7 @@
 			this.tableLayoutPanel2.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel2.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel2.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Percent, 100F));
-			this.tableLayoutPanel2.Size = new System.Drawing.Size(400, 258);
+			this.tableLayoutPanel2.Size = new System.Drawing.Size(431, 258);
 			this.tableLayoutPanel2.TabIndex = 5;
 			// 
 			// chkEnableRandomPowerOnState
@@ -403,13 +474,23 @@
 			this.lblRamPowerOnState.TabIndex = 0;
 			this.lblRamPowerOnState.Text = "Default power on state for RAM:";
 			// 
+			// chkEnableStrictBoardMappings
+			// 
+			this.chkEnableStrictBoardMappings.Checked = false;
+			this.tableLayoutPanel2.SetColumnSpan(this.chkEnableStrictBoardMappings, 2);
+			this.chkEnableStrictBoardMappings.Location = new System.Drawing.Point(0, 51);
+			this.chkEnableStrictBoardMappings.Name = "chkEnableStrictBoardMappings";
+			this.chkEnableStrictBoardMappings.Size = new System.Drawing.Size(400, 24);
+			this.chkEnableStrictBoardMappings.TabIndex = 7;
+			this.chkEnableStrictBoardMappings.Text = "Use strict board mappings (breaks some romhacks)";
+			// 
 			// tpgOverclocking
 			// 
 			this.tpgOverclocking.Controls.Add(this.picHint);
 			this.tpgOverclocking.Controls.Add(this.tableLayoutPanel3);
 			this.tpgOverclocking.Location = new System.Drawing.Point(4, 22);
 			this.tpgOverclocking.Name = "tpgOverclocking";
-			this.tpgOverclocking.Size = new System.Drawing.Size(406, 264);
+			this.tpgOverclocking.Size = new System.Drawing.Size(437, 264);
 			this.tpgOverclocking.TabIndex = 4;
 			this.tpgOverclocking.Text = "Overclocking";
 			this.tpgOverclocking.UseVisualStyleBackColor = true;
@@ -442,7 +523,7 @@
 			this.tableLayoutPanel3.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel3.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel3.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Percent, 100F));
-			this.tableLayoutPanel3.Size = new System.Drawing.Size(406, 264);
+			this.tableLayoutPanel3.Size = new System.Drawing.Size(437, 264);
 			this.tableLayoutPanel3.TabIndex = 1;
 			// 
 			// lblOverclockHint
@@ -461,7 +542,7 @@
 			this.grpPpuTiming.Dock = System.Windows.Forms.DockStyle.Fill;
 			this.grpPpuTiming.Location = new System.Drawing.Point(3, 57);
 			this.grpPpuTiming.Name = "grpPpuTiming";
-			this.grpPpuTiming.Size = new System.Drawing.Size(400, 71);
+			this.grpPpuTiming.Size = new System.Drawing.Size(431, 71);
 			this.grpPpuTiming.TabIndex = 7;
 			this.grpPpuTiming.TabStop = false;
 			this.grpPpuTiming.Text = "PPU Vertical Blank Configuration";
@@ -482,7 +563,7 @@
 			this.tableLayoutPanel5.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel5.RowStyles.Add(new System.Windows.Forms.RowStyle());
 			this.tableLayoutPanel5.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Percent, 100F));
-			this.tableLayoutPanel5.Size = new System.Drawing.Size(394, 52);
+			this.tableLayoutPanel5.Size = new System.Drawing.Size(425, 52);
 			this.tableLayoutPanel5.TabIndex = 0;
 			// 
 			// nudExtraScanlinesAfterNmi
@@ -582,7 +663,7 @@
 			this.tableLayoutPanel1.Name = "tableLayoutPanel1";
 			this.tableLayoutPanel1.RowCount = 1;
 			this.tableLayoutPanel1.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Percent, 100F));
-			this.tableLayoutPanel1.Size = new System.Drawing.Size(406, 25);
+			this.tableLayoutPanel1.Size = new System.Drawing.Size(437, 25);
 			this.tableLayoutPanel1.TabIndex = 8;
 			// 
 			// nudGsuClockSpeed
@@ -628,21 +709,11 @@
 			this.lblGsuClockSpeed.TabIndex = 0;
 			this.lblGsuClockSpeed.Text = "Super FX clock speed (%):";
 			// 
-			// chkEnableStrictBoardMappings
-			// 
-			this.chkEnableStrictBoardMappings.Checked = false;
-			this.tableLayoutPanel2.SetColumnSpan(this.chkEnableStrictBoardMappings, 2);
-			this.chkEnableStrictBoardMappings.Location = new System.Drawing.Point(0, 51);
-			this.chkEnableStrictBoardMappings.Name = "chkEnableStrictBoardMappings";
-			this.chkEnableStrictBoardMappings.Size = new System.Drawing.Size(400, 24);
-			this.chkEnableStrictBoardMappings.TabIndex = 7;
-			this.chkEnableStrictBoardMappings.Text = "Use strict board mappings (breaks some romhacks)";
-			// 
 			// frmEmulationConfig
 			// 
 			this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
 			this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
-			this.ClientSize = new System.Drawing.Size(414, 319);
+			this.ClientSize = new System.Drawing.Size(445, 319);
 			this.Controls.Add(this.tabMain);
 			this.FormBorderStyle = System.Windows.Forms.FormBorderStyle.FixedSingle;
 			this.MaximizeBox = false;
@@ -657,6 +728,8 @@
 			this.tpgGeneral.PerformLayout();
 			this.tableLayoutPanel4.ResumeLayout(false);
 			this.tableLayoutPanel4.PerformLayout();
+			this.flowLayoutPanel5.ResumeLayout(false);
+			this.flowLayoutPanel5.PerformLayout();
 			this.flowLayoutPanel9.ResumeLayout(false);
 			this.flowLayoutPanel9.PerformLayout();
 			this.flowLayoutPanel6.ResumeLayout(false);
@@ -718,5 +791,9 @@
 		private System.Windows.Forms.TableLayoutPanel tableLayoutPanel2;
 		private Controls.ctrlRiskyOption chkEnableRandomPowerOnState;
 		private Controls.ctrlRiskyOption chkEnableStrictBoardMappings;
-	}
+	  private System.Windows.Forms.FlowLayoutPanel flowLayoutPanel5;
+	  private Controls.MesenNumericUpDown nudRunAheadFrames;
+	  private System.Windows.Forms.Label lblRunAheadFrames;
+	  private System.Windows.Forms.Label lblRunAhead;
+   }
 }

UI/Forms/Config/frmEmulationConfig.cs

@@ -26,6 +26,7 @@ namespace Mesen.GUI.Forms.Config
 			AddBinding(nameof(EmulationConfig.TurboSpeed), nudTurboSpeed);
 			AddBinding(nameof(EmulationConfig.RewindSpeed), nudRewindSpeed);
 			AddBinding(nameof(EmulationConfig.Region), cboRegion);
+			AddBinding(nameof(EmulationConfig.RunAheadFrames), nudRunAheadFrames);
 
 			AddBinding(nameof(EmulationConfig.RamPowerOnState), cboRamPowerOnState);
 			AddBinding(nameof(EmulationConfig.EnableRandomPowerOnState), chkEnableRandomPowerOnState);

Utilities/Serializer.cpp

@@ -8,49 +8,60 @@ Serializer::Serializer(uint32_t version)
 {
 	_version = version;
 
-	_block.Data = vector<uint8_t>(0x50000);
+	_block.reset(new BlockData());
-	_block.Position = 0;
+	_block->Data = vector<uint8_t>(0x50000);
+	_block->Position = 0;
 	_saving = true;
 }
 
-Serializer::Serializer(istream &file, uint32_t version)
+Serializer::Serializer(istream &file, uint32_t version, bool compressed)
 {
 	_version = version;
 
-	_block.Position = 0;
+	_block.reset(new BlockData());
+	_block->Position = 0;
 	_saving = false;
 
-	uint32_t decompressedSize;
+	if(compressed) {
-	file.read((char*)&decompressedSize, sizeof(decompressedSize));
+		uint32_t decompressedSize;
+		file.read((char*)&decompressedSize, sizeof(decompressedSize));
 
-	uint32_t compressedSize;
+		uint32_t compressedSize;
-	file.read((char*)&compressedSize, sizeof(compressedSize));
+		file.read((char*)&compressedSize, sizeof(compressedSize));
 
-	vector<uint8_t> compressedData(compressedSize, 0);
+		vector<uint8_t> compressedData(compressedSize, 0);
-	file.read((char*)compressedData.data(), compressedSize);
+		file.read((char*)compressedData.data(), compressedSize);
 
-	_block.Data = vector<uint8_t>(decompressedSize, 0);
+		_block->Data = vector<uint8_t>(decompressedSize, 0);
 
-	unsigned long decompSize = decompressedSize;
+		unsigned long decompSize = decompressedSize;
-	uncompress(_block.Data.data(), &decompSize, compressedData.data(), (unsigned long)compressedData.size());
+		uncompress(_block->Data.data(), &decompSize, compressedData.data(), (unsigned long)compressedData.size());
+	} else {
+		file.seekg(0, std::ios::end);
+		uint32_t size = (uint32_t)file.tellg();
+		file.seekg(0, std::ios::beg);
+
+		_block->Data = vector<uint8_t>(size, 0);
+		file.read((char*)_block->Data.data(), size);
+	}
 }
 
 void Serializer::EnsureCapacity(uint32_t typeSize)
 {
 	//Make sure the current block/stream is large enough to fit the next write
-	uint32_t oldSize = (uint32_t)_block.Data.size();
+	uint32_t oldSize = (uint32_t)_block->Data.size();
 	if(oldSize == 0) {
 		oldSize = typeSize * 2;
 	}
 
-	uint32_t sizeRequired = _block.Position + typeSize;
+	uint32_t sizeRequired = _block->Position + typeSize;
 	
 	uint32_t newSize = oldSize;
 	while(newSize < sizeRequired) {
 		newSize *= 2;
 	}
 
-	_block.Data.resize(newSize);
+	_block->Data.resize(newSize);
 }
 
 void Serializer::RecursiveStream()
@@ -59,18 +70,18 @@ void Serializer::RecursiveStream()
 
 void Serializer::StreamStartBlock()
 {
-	BlockData block;
+	unique_ptr<BlockData> block(new BlockData());
-	block.Position = 0;
+	block->Position = 0;
 
 	if(!_saving) {
-		VectorInfo<uint8_t> vectorInfo = { &block.Data };
+		VectorInfo<uint8_t> vectorInfo = { &block->Data };
 		InternalStream(vectorInfo);
 	} else {
-		block.Data = vector<uint8_t>(0x100);
+		block->Data = vector<uint8_t>(0x100);
 	}
 
-	_blocks.push_back(_block);
+	_blocks.push_back(std::move(_block));
-	_block = block;
+	_block = std::move(block);
 }
 
 void Serializer::StreamEndBlock()
@@ -79,28 +90,32 @@ void Serializer::StreamEndBlock()
 		throw std::runtime_error("Invalid call to end block");
 	}
 
-	BlockData block = _block;
+	unique_ptr<BlockData> block = std::move(_block);
 
-	_block = _blocks.back();
+	_block = std::move(_blocks.back());
 	_blocks.pop_back();
 
 	if(_saving) {
-		ArrayInfo<uint8_t> arrayInfo { block.Data.data(), block.Position };
+		ArrayInfo<uint8_t> arrayInfo { block->Data.data(), block->Position };
 		InternalStream(arrayInfo);
 	}
 }
 
 void Serializer::Save(ostream& file, int compressionLevel)
 {
-	unsigned long compressedSize = compressBound((unsigned long)_block.Position);
+	if(compressionLevel == 0) {
-	uint8_t* compressedData = new uint8_t[compressedSize];
+		file.write((char*)_block->Data.data(), _block->Position);
-	compress2(compressedData, &compressedSize, (unsigned char*)_block.Data.data(), (unsigned long)_block.Position, compressionLevel);
+	} else {
+		unsigned long compressedSize = compressBound((unsigned long)_block->Position);
+		uint8_t* compressedData = new uint8_t[compressedSize];
+		compress2(compressedData, &compressedSize, (unsigned char*)_block->Data.data(), (unsigned long)_block->Position, compressionLevel);
 
-	uint32_t size = (uint32_t)compressedSize;
+		uint32_t size = (uint32_t)compressedSize;
-	file.write((char*)&_block.Position, sizeof(uint32_t));
+		file.write((char*)&_block->Position, sizeof(uint32_t));
-	file.write((char*)&size, sizeof(uint32_t));
+		file.write((char*)&size, sizeof(uint32_t));
-	file.write((char*)compressedData, compressedSize);
+		file.write((char*)compressedData, compressedSize);
-	delete[] compressedData;
+		delete[] compressedData;
+	}
 }
 
 void Serializer::WriteEmptyBlock(ostream* file)

Utilities/Serializer.h

@@ -34,9 +34,8 @@ struct BlockData
 class Serializer
 {
 private:
-	vector<BlockData> _blocks;
+	vector<unique_ptr<BlockData>> _blocks;	
-	
+	unique_ptr<BlockData> _block;
-	BlockData _block;
 
 	uint32_t _version = 0;
 	bool _saving = false;
@@ -60,7 +59,7 @@ private:
 
 public:
 	Serializer(uint32_t version);
-	Serializer(istream &file, uint32_t version);
+	Serializer(istream &file, uint32_t version, bool compressed = true);
 
 	uint32_t GetVersion() { return _version; }
 	bool IsSaving() { return _saving; }
@@ -87,15 +86,15 @@ void Serializer::StreamElement(T &value, T defaultValue)
 
 		EnsureCapacity(typeSize);
 		for(int i = 0; i < typeSize; i++) {
-			_block.Data[_block.Position++] = bytes[i];
+			_block->Data[_block->Position++] = bytes[i];
 		}
 	} else {
-		if(_block.Position + sizeof(T) <= _block.Data.size()) {
+		if(_block->Position + sizeof(T) <= _block->Data.size()) {
-			memcpy(&value, _block.Data.data() + _block.Position, sizeof(T));
+			memcpy(&value, _block->Data.data() + _block->Position, sizeof(T));
-			_block.Position += sizeof(T);
+			_block->Position += sizeof(T);
 		} else {
 			value = defaultValue;
-			_block.Position = (uint32_t)_block.Data.size();
+			_block->Position = (uint32_t)_block->Data.size();
 		}
 	}
 }
@@ -115,11 +114,11 @@ void Serializer::InternalStream(ArrayInfo<T> &info)
 	EnsureCapacity(info.ElementCount * sizeof(T));
 
 	if(_saving) {
-		memcpy(_block.Data.data() + _block.Position, info.Array, info.ElementCount * sizeof(T));
+		memcpy(_block->Data.data() + _block->Position, info.Array, info.ElementCount * sizeof(T));
 	} else {
-		memcpy(info.Array, _block.Data.data() + _block.Position, info.ElementCount * sizeof(T));
+		memcpy(info.Array, _block->Data.data() + _block->Position, info.ElementCount * sizeof(T));
 	}
-	_block.Position += info.ElementCount * sizeof(T);
+	_block->Position += info.ElementCount * sizeof(T);
 }
 
 template<typename T>