- Nik's new decoupled audio code with fixes to minimize overruns.

- VBlank timing: increased to 20% of a frame.

Src/Model3/DSB.cpp

@@ -509,6 +509,10 @@ void CDSB1::SaveState(CBlockFile *StateFile)
 	
 	// Z80 CPU state
 	Z80.SaveState(StateFile, "DSB1 Z80");
+	
+	//DEBUG
+	//printf("usingMPEGStart=%X usingMPEGEnd=%X\n", usingMPEGStart, usingMPEGEnd);
+	//printf("usingLoopStart=%X usingLoopEnd=%X\n", usingLoopStart, usingLoopEnd);
 }
 
 void CDSB1::LoadState(CBlockFile *StateFile)
@@ -554,6 +558,10 @@ void CDSB1::LoadState(CBlockFile *StateFile)
 	}
 	else
 		MPEG_StopPlaying();
+		
+	//DEBUG
+	//printf("usingMPEGStart=%X usingMPEGEnd=%X\n", usingMPEGStart, usingMPEGEnd);
+	//printf("usingLoopStart=%X usingLoopEnd=%X\n", usingLoopStart, usingLoopEnd);
 }
 
 // Offsets of memory regions within DSB1's pool
@@ -1065,6 +1073,11 @@ void CDSB2::SaveState(CBlockFile *StateFile)
 	// 68K CPU state
 	M68KSetContext(&M68K);
 	M68KSaveState(StateFile, "DSB2 68K");
+	
+	//DEBUG
+	//printf("mpegStart=%X, mpegEnd=%X\n", mpegStart, mpegEnd);
+	//printf("usingMPEGStart=%X, usingMPEGEnd=%X\n", usingMPEGStart, usingMPEGEnd);
+	//printf("usingLoopStart=%X, usingLoopEnd=%X\n", usingLoopStart, usingLoopEnd);
 }
 
 void CDSB2::LoadState(CBlockFile *StateFile)

Src/Model3/Model3.cpp

@@ -1917,8 +1917,8 @@ void CModel3::RunFrame(void)
 		if (!StartThreads())
 			goto ThreadError;
 
-		// Wake sound board and drive board threads so they can process a frame
+		// Wake threads for sound board (if sync'd) and drive board (if attached) so they can process a frame
-		if (!sndBrdThreadSync->Post() || DriveBoard.IsAttached() && !drvBrdThreadSync->Post())
+		if (syncSndBrdThread && !sndBrdThreadSync->Post() || DriveBoard.IsAttached() && !drvBrdThreadSync->Post())
 			goto ThreadError;
 
 		// At the same time, process a single frame for main board (PPC) in this thread
@@ -1929,7 +1929,7 @@ void CModel3::RunFrame(void)
 			goto ThreadError;
 
 		// Wait for sound board and drive board threads to finish their work (if they haven't done so already)
-		while (!sndBrdThreadDone || DriveBoard.IsAttached() && !drvBrdThreadDone)
+		while (syncSndBrdThread && !sndBrdThreadDone || DriveBoard.IsAttached() && !drvBrdThreadDone)
 		{
 			if (!notifySync->Wait(notifyLock))
 				goto ThreadError;
@@ -1957,7 +1957,7 @@ ThreadError:
 	g_Config.multiThreaded = false;
 }
 
-bool CModel3::StartThreads()
+bool CModel3::StartThreads(void)
 {
 	if (startedThreads)
 		return true;
@@ -1966,6 +1966,12 @@ bool CModel3::StartThreads()
 	sndBrdThreadSync = CThread::CreateSemaphore(1);
 	if (sndBrdThreadSync == NULL)
 		goto ThreadError;
+	sndBrdNotifyLock = CThread::CreateMutex();
+	if (sndBrdNotifyLock == NULL)
+		goto ThreadError;
+	sndBrdNotifySync = CThread::CreateCondVar();
+	if (sndBrdNotifySync == NULL)
+		goto ThreadError;
 	if (DriveBoard.IsAttached())
 	{
 		drvBrdThreadSync = CThread::CreateSemaphore(1);
@@ -1979,19 +1985,26 @@ bool CModel3::StartThreads()
 	if (notifySync == NULL)
 		goto ThreadError;
 
-	// Create sound board thread
+	// Create sound board thread (sync'd or unsync'd)
+	if (syncSndBrdThread)
+		sndBrdThread = CThread::CreateThread(StartSoundBoardThreadSyncd, this);
+	else
 		sndBrdThread = CThread::CreateThread(StartSoundBoardThread, this);
 	if (sndBrdThread == NULL)
 		goto ThreadError;
 
-	// Create drive board thread, if drive board is attached
+	// Create drive board thread (sync'd), if drive board is attached
 	if (DriveBoard.IsAttached())
 	{
-		drvBrdThread = CThread::CreateThread(StartDriveBoardThread, this);
+		drvBrdThread = CThread::CreateThread(StartDriveBoardThreadSyncd, this);
 		if (drvBrdThread == NULL)
 			goto ThreadError;
 	}
 
+	// Set audio callback if unsync'd
+	if (!syncSndBrdThread)
+		SetAudioCallback(AudioCallback, this);
+	
 	startedThreads = true;
 	return true;
 
@@ -2002,16 +2015,55 @@ ThreadError:
 	return false;
 }
 
-void CModel3::StopThreads()
+bool CModel3::PauseThreads(void)
+{
+	if (!startedThreads)
+		return true;
+	
+	// Enter notify critical section
+	if (!notifyLock->Lock())
+		goto ThreadError;
+
+	// Wait for all threads to finish their processing
+	pausedThreads = true;
+	while (sndBrdThreadRunning || drvBrdThreadRunning)
+	{
+		if (!notifySync->Wait(notifyLock))
+			goto ThreadError;
+	}
+
+	// Leave notify critical section
+	if (!notifyLock->Unlock())
+		goto ThreadError;
+	return true;
+
+ThreadError:
+	ErrorLog("Threading error in CModel3::PauseThreads: %s\nSwitching back to single-threaded mode.\n", CThread::GetLastError());
+	g_Config.multiThreaded = false;
+	return false;
+}
+
+void CModel3::ResumeThreads(void)
+{	
+	// No need to use any locking here
+	pausedThreads = false;
+	return;
+}
+
+void CModel3::StopThreads(void)
 {
 	if (!startedThreads)
 		return;
 
+	// Remove callback
+	if (!syncSndBrdThread)
+		SetAudioCallback(NULL, NULL);
+
 	DeleteThreadObjects();
 	startedThreads = false;
 }
 
-void CModel3::DeleteThreadObjects()
+void CModel3::DeleteThreadObjects(void)
 {
 	// Delete (which in turn kills) sound board and drive board threads
 	// Note that can do so here safely because threads will always be waiting on their semaphores when this method is called
@@ -2037,6 +2089,16 @@ void CModel3::DeleteThreadObjects()
 		delete drvBrdThreadSync;
 		drvBrdThreadSync = NULL;
 	}
+	if (sndBrdNotifyLock != NULL)
+	{
+		delete sndBrdNotifyLock;
+		sndBrdNotifyLock = NULL;
+	}
+	if (sndBrdNotifySync != NULL)
+	{
+		delete sndBrdNotifySync;
+		sndBrdNotifySync = NULL;
+	}
 	if (notifyLock != NULL)
 	{
 		delete notifyLock;
@@ -2051,28 +2113,145 @@ void CModel3::DeleteThreadObjects()
 
 int CModel3::StartSoundBoardThread(void *data)
 {
-	// Call sound board thread method on CModel3
+	// Call method on CModel3 to run unsync'd sound board thread
 	CModel3 *model3 = (CModel3*)data;
 	model3->RunSoundBoardThread();
 	return 0;
 }
 
-int CModel3::StartDriveBoardThread(void *data)
+int CModel3::StartSoundBoardThreadSyncd(void *data)
 {
-	// Call drive board thread method on CModel3
+	// Call method on CModel3 to run sync'd sound board thread
 	CModel3 *model3 = (CModel3*)data;
-	model3->RunDriveBoardThread();
+	model3->RunSoundBoardThreadSyncd();
 	return 0;
 }
 
-void CModel3::RunSoundBoardThread()
+int CModel3::StartDriveBoardThreadSyncd(void *data)
+{
+	// Call method on CModel3 to run sync'd drive board thread
+	CModel3 *model3 = (CModel3*)data;
+	model3->RunDriveBoardThreadSyncd();
+	return 0;
+}
+
+void CModel3::AudioCallback(void *data)
+{
+	// Call method on CModel3 to wake sound board thread
+	CModel3 *model3 = (CModel3*)data;
+	model3->WakeSoundBoardThread();
+}
+
+void CModel3::WakeSoundBoardThread(void)
+{
+	// Enter sound board notify critical section
+	if (!sndBrdNotifyLock->Lock())
+		goto ThreadError;
+
+	// Signal to sound board that it should start processing again
+	if (!sndBrdNotifySync->Signal())
+		goto ThreadError;
+
+	// Exit sound board notify critical section
+	if (!sndBrdNotifyLock->Unlock())
+		goto ThreadError;
+	return;
+
+ThreadError:
+	ErrorLog("Threading error in WakeSoundBoardThread: %s\nSwitching back to single-threaded mode.\n", CThread::GetLastError());
+	g_Config.multiThreaded = false;
+}
+
+void CModel3::RunSoundBoardThread(void)
 {
 	for (;;)
+	{
+		bool wait = true;
+		while (wait)
+		{
+			// Enter sound board notify critical section
+			if (!sndBrdNotifyLock->Lock())
+				goto ThreadError;
+
+			// Wait for notification from audio callback
+			if (!sndBrdNotifySync->Wait(sndBrdNotifyLock))
+				goto ThreadError;
+
+			// Exit sound board notify critical section
+			if (!sndBrdNotifyLock->Unlock())
+				goto ThreadError;
+	
+			// Enter main notify critical section
+			if (!notifyLock->Lock())
+				goto ThreadError;
+
+			// Check threads not paused
+			if (!pausedThreads)
+			{
+				wait = false;
+				sndBrdThreadRunning = true;
+			}
+
+			// Leave main notify critical section
+			if (!notifyLock->Unlock())
+				goto ThreadError;
+		}
+
+		// Keep processing frames until audio buffer is half full
+		bool repeat = true;
+		// NOTE - performs an unlocked read of pausedThreads here, but this is okay
+		while (!pausedThreads && !SoundBoard.RunFrame())
+		{
+			//printf("Rerunning sound board\n");
+		}
+
+		// Enter main notify critical section
+		if (!notifyLock->Lock())
+			goto ThreadError;
+
+		// Let other threads know processing has finished
+		sndBrdThreadRunning = false;
+		sndBrdThreadDone = true;
+		if (!notifySync->SignalAll())
+			goto ThreadError;
+
+		// Leave main notify critical section
+		if (!notifyLock->Unlock())
+			goto ThreadError;
+	}
+
+ThreadError:
+	ErrorLog("Threading error in RunSoundBoardThread: %s\nSwitching back to single-threaded mode.\n", CThread::GetLastError());
+	g_Config.multiThreaded = false;
+}
+
+void CModel3::RunSoundBoardThreadSyncd(void)
+{
+	for (;;)
+	{
+		bool wait = true;
+		while (wait)
 		{
 			// Wait on sound board thread semaphore
 			if (!sndBrdThreadSync->Wait())
 				goto ThreadError;
 	
+			// Enter notify critical section
+			if (!notifyLock->Lock())
+				goto ThreadError;
+
+			// Check threads not paused
+			if (!pausedThreads)
+			{
+				wait = false;
+				sndBrdThreadRunning = true;
+			}
+
+			// Leave notify critical section
+			if (!notifyLock->Unlock())
+				goto ThreadError;
+		}
+
 		// Process a single frame for sound board
 		SoundBoard.RunFrame();
 
@@ -2080,9 +2259,10 @@ void CModel3::RunSoundBoardThread()
 		if (!notifyLock->Lock())
 			goto ThreadError;
 
-		// Let main thread know processing has finished
+		// Let other threads know processing has finished
+		sndBrdThreadRunning = false;
 		sndBrdThreadDone = true;
-		if (!notifySync->Signal())
+		if (!notifySync->SignalAll())
 			goto ThreadError;
 
 		// Leave notify critical section
@@ -2091,18 +2271,37 @@ void CModel3::RunSoundBoardThread()
 	}
 
 ThreadError:
-	ErrorLog("Threading error in sound board thread: %s\nSwitching back to single-threaded mode.\n", CThread::GetLastError());
+	ErrorLog("Threading error in RunSoundBoardThreadSyncd: %s\nSwitching back to single-threaded mode.\n", CThread::GetLastError());
 	g_Config.multiThreaded = false;
 }
 
-void CModel3::RunDriveBoardThread()
+void CModel3::RunDriveBoardThreadSyncd(void)
 {
 	for (;;)
+	{
+		bool wait = true;
+		while (wait)
 		{
 			// Wait on drive board thread semaphore
 			if (!drvBrdThreadSync->Wait())
 				goto ThreadError;
 
+			// Enter notify critical section
+			if (!notifyLock->Lock())
+				goto ThreadError;
+
+			// Check threads not paused
+			if (!pausedThreads)
+			{
+				wait = false;
+				drvBrdThreadRunning = true;
+			}
+	
+			// Leave notify critical section
+			if (!notifyLock->Unlock())
+				goto ThreadError;
+		}
+
 		// Process a single frame for drive board
 		DriveBoard.RunFrame();
 
@@ -2110,9 +2309,10 @@ void CModel3::RunDriveBoardThread()
 		if (!notifyLock->Lock())
 			goto ThreadError;
 
-		// Let main thread know processing has finished
+		// Let other threads know processing has finished
+		drvBrdThreadRunning = false;
 		drvBrdThreadDone = true;
-		if (!notifySync->Signal())
+		if (!notifySync->SignalAll())
 			goto ThreadError;
 
 		// Leave notify critical section
@@ -2121,13 +2321,19 @@ void CModel3::RunDriveBoardThread()
 	}
 
 ThreadError:
-	ErrorLog("Threading error in drive board thread: %s\nSwitching back to single-threaded mode.\n", CThread::GetLastError());
+	ErrorLog("Threading error in RunDriveBoardThreadSyncd: %s\nSwitching back to single-threaded mode.\n", CThread::GetLastError());
 	g_Config.multiThreaded = false;
 }
+
 void CModel3::RunMainBoardFrame(void)
 {
-	// Run the PowerPC for a frame
+	// Compute display and VBlank timings
-	ppc_execute(g_Config.GetPowerPCFrequency()*1000000/60-10000);
+	unsigned	frameCycles = g_Config.GetPowerPCFrequency()*1000000/60;
+	unsigned	vblCycles = (unsigned) ((float) frameCycles * 20.0f/100.0f);	// 20% vblank (just a guess; probably too long)
+	unsigned	dispCycles = frameCycles - vblCycles;
+	
+	// Run the PowerPC for the active display part of the frame
+	ppc_execute(dispCycles);
 	//printf("PC=%08X LR=%08X\n", ppc_get_pc(), ppc_get_lr());
 	
 	// VBlank
@@ -2135,7 +2341,7 @@ void CModel3::RunMainBoardFrame(void)
 	GPU.BeginFrame();
 	GPU.RenderFrame();
 	IRQ.Assert(0x02);
-	ppc_execute(10000);     // TO-DO: Vblank probably needs to be longer. Maybe that's why some games run too fast/slow
+	ppc_execute(vblCycles);
 	//printf("PC=%08X LR=%08X\n", ppc_get_pc(), ppc_get_lr());	
 	
 	/*
@@ -2736,10 +2942,14 @@ CModel3::CModel3(void)
 	securityPtr = 0;
 	
 	startedThreads = false;
+	pausedThreads = false;
 	sndBrdThread = NULL; 
 	drvBrdThread = NULL;
+	sndBrdThreadRunning = false;
 	sndBrdThreadDone = false;
+	drvBrdThreadRunning = false;
 	drvBrdThreadDone = false;
+	syncSndBrdThread = false;
 	sndBrdThreadSync = NULL;
 	drvBrdThreadSync = NULL;
 	notifyLock = NULL;

Src/Model3/Model3.h

@@ -291,6 +291,9 @@ public:
 	CModel3(void);
 	~CModel3(void);
 
+	bool PauseThreads(void);
+	void ResumeThreads(void);
+
 	/*
 	 * Private Property.
 	 * Tresspassers will be shot! ;)
@@ -306,16 +309,21 @@ private:
 	void 	WriteSystemRegister(unsigned reg, UINT8 data);
 	void	Patch(void);
 
-	void    RunMainBoardFrame();    // Runs the main board (PPC) for a frame
+	void    RunMainBoardFrame(void);                   // Runs the main board (PPC) for a frame
-	bool    StartThreads();         // Starts all threads
+	bool    StartThreads(void);                        // Starts all threads
-	void    StopThreads();          // Stops all threads
+	void    StopThreads(void);                         // Stops all threads
-	void    DeleteThreadObjects();  // Deletes all threads and synchronization objects
+	void    DeleteThreadObjects(void);                 // Deletes all threads and synchronization objects
 
-	static int StartSoundBoardThread(void *data);    // Callback to start sound board thread
+	static int StartSoundBoardThread(void *data);      // Callback to start unsync'd sound board thread
-	static int StartDriveBoardThread(void *data);    // Callback to start drive board thread
+	static int StartSoundBoardThreadSyncd(void *data); // Callback to start sync'd sound board thread
+	static int StartDriveBoardThreadSyncd(void *data); // Callback to start sync'd drive board thread
 
-	void    RunSoundBoardThread();                   // Runs sound board thread 
+	static void AudioCallback(void *data);             // Audio buffer callback
-	void    RunDriveBoardThread();                   // Runs drive board thread
+	
+	void    WakeSoundBoardThread(void);	               // Used by audio callback to wake sound board thread when not sync'd with PPC thread
+	void    RunSoundBoardThread(void);                 // Runs sound board thread unsync'd with PPC thread, ie at full speed
+	void    RunSoundBoardThreadSyncd(void);            // Runs sound board thread sync'd in step with PPC thread
+	void    RunDriveBoardThreadSyncd(void);            // Runs drive board thread sync'd in step with PPC thread
 	
 	// Game and hardware information
 	const struct GameInfo	*Game;
@@ -357,13 +365,19 @@ private:
 
 	// Multiple threading
 	bool        startedThreads;      // True if threads have been created and started
+	bool        pausedThreads;       // True if threads are currently paused
 	CThread     *sndBrdThread;       // Sound board thread
 	CThread     *drvBrdThread;       // Drive board thread
-	bool        sndBrdThreadDone;  // Flag to indicate sound board thread has finished processing for current frame
+	bool        sndBrdThreadRunning; // Flag to indicate sound board thread is currently processing
-	bool        drvBrdThreadDone;  // Flag to indicate drive board thread has finished processing for current frame
+	bool        sndBrdThreadDone;    // Flag to indicate sound board thread has finished processing
+	bool        drvBrdThreadRunning; // Flag to indicate drive board thread is currently processing
+	bool        drvBrdThreadDone;    // Flag to indicate drive board thread has finished processing
 
 	// Thread synchronization objects
+	bool        syncSndBrdThread;
 	CSemaphore  *sndBrdThreadSync;
+	CMutex      *sndBrdNotifyLock;
+	CCondVar    *sndBrdNotifySync;
 	CSemaphore  *drvBrdThreadSync;
 	CMutex      *notifyLock;
 	CCondVar    *notifySync;	

Src/Model3/SoundBoard.cpp

@@ -1,4 +1,3 @@
-//TODO: before release, comment out printf()'s
 /**
  ** Supermodel
  ** A Sega Model 3 Arcade Emulator.
@@ -358,7 +357,7 @@ void CSoundBoard::WriteMIDIPort(UINT8 data)
 		DSB->SendCommand(data);
 }
 
-void CSoundBoard::RunFrame(void)
+bool CSoundBoard::RunFrame(void)
 {
 #ifdef SUPERMODEL_SOUND
 	// Run sound board first to generate SCSP audio
@@ -379,7 +378,7 @@ void CSoundBoard::RunFrame(void)
 		DSB->RunFrame(audioL, audioR);
 
 	// Output the audio buffers
-	OutputAudio(44100/60, audioL, audioR);
+	bool bufferFull = OutputAudio(44100/60, audioL, audioR);
 
 #ifdef SUPERMODEL_LOG_AUDIO
 	// Output to binary file
@@ -391,8 +390,10 @@ void CSoundBoard::RunFrame(void)
 		s = audioR[i];
 		fwrite(&s, sizeof(INT16), 1, soundFP);	// right channel
 	}
-#endif
+#endif // SUPERMODEL_LOG_AUDIO
-#endif
+#endif // SUPERMODEL_SOUND
+
+	return bufferFull;
 }
 
 void CSoundBoard::Reset(void)

Src/Model3/SoundBoard.h

@@ -126,7 +126,7 @@ public:
 	 *
 	 * Runs the sound board for one frame, updating sound in the process.
 	 */
-	void RunFrame(void);
+	bool RunFrame(void);
 	
 	/*
 	 * Reset(void):

Src/OSD/Audio.h

@@ -7,6 +7,12 @@
  * Function-based interface for audio output.
  */
 
+typedef void (*AudioCallbackFPtr)(void *data);
+
+extern void SetAudioCallback(AudioCallbackFPtr callback, void *data);
+
+extern void SetAudioEnabled(bool enabled);
+
 /*
  * OpenAudio()
  *
@@ -19,7 +25,7 @@ extern bool OpenAudio();
  *
  * Sends a chunk of two-channel audio with the given number of samples to the audio system.
  */
-extern void OutputAudio(unsigned numSamples, INT16 *leftBuffer, INT16 *rightBuffer);
+extern bool OutputAudio(unsigned numSamples, INT16 *leftBuffer, INT16 *rightBuffer);
 
 /*
  * CloseAudio()

Src/OSD/SDL/Audio.cpp

@@ -38,6 +38,25 @@ static bool writeWrapped = false;   // True if write position has wrapped around
 static unsigned underRuns = 0;      // Number of buffer under-runs that have occured
 static unsigned overRuns = 0;       // Number of buffer over-runs that have occured
 
+static AudioCallbackFPtr callback = NULL;
+static void *callbackData = NULL;
+
+void SetAudioCallback(AudioCallbackFPtr newCallback, void *newData)
+{
+	// Lock audio whilst changing callback pointers
+	SDL_LockAudio();
+
+	callback = newCallback;
+	callbackData = newData;
+
+	SDL_UnlockAudio();
+}
+
+void SetAudioEnabled(bool newEnabled)
+{
+	enabled = newEnabled;
+}
+
 static void PlayCallback(void *data, Uint8 *stream, int len)
 {
 	//printf("PlayCallback(%d) [writePos = %u, writeWrapped = %s, playPos = %u, audioBufferSize = %u]\n", 
@@ -128,6 +147,8 @@ static void PlayCallback(void *data, Uint8 *stream, int len)
 	// Move play position forward for next time
 	playPos += len;
 
+	bool halfEmpty = adjWritePos + audioBufferSize / 2 - BYTES_PER_FRAME / 2 < playPos + audioBufferSize;
+	
 	// Check if play position has moved past end of buffer
 	if (playPos >= audioBufferSize)
 	{
@@ -135,6 +156,10 @@ static void PlayCallback(void *data, Uint8 *stream, int len)
 		playPos -= audioBufferSize;
 		writeWrapped = false;
 	}
+
+	// If buffer is more than half empty then call callback
+	if (callback && halfEmpty)
+		callback(callbackData);
 }
 
 static void MixChannels(unsigned numSamples, INT16 *leftBuffer, INT16 *rightBuffer, void *dest)
@@ -227,11 +252,13 @@ bool OpenAudio()
 	return OKAY;
 }
 
-void OutputAudio(unsigned numSamples, INT16 *leftBuffer, INT16 *rightBuffer)
+bool OutputAudio(unsigned numSamples, INT16 *leftBuffer, INT16 *rightBuffer)
 {
 	//printf("OutputAudio(%u) [writePos = %u, writeWrapped = %s, playPos = %u, audioBufferSize = %u]\n",
 	//	numSamples, writePos, (writeWrapped ? "true" : "false"), playPos, audioBufferSize);
 
+	bool halfFull = false;
+
 	UINT32 bytesRemaining;
 	UINT32 bytesToCopy;
 	INT16 *src;
@@ -296,6 +323,9 @@ void OutputAudio(unsigned numSamples, INT16 *leftBuffer, INT16 *rightBuffer)
 	// Check if write position has caught up with play region and now overlaps it (ie buffer over-run)
 	bool overRun = writePos + numBytes > playPos + audioBufferSize;
 	
+	if (writePos + audioBufferSize / 2 + BYTES_PER_FRAME / 2 > playPos + audioBufferSize)
+		halfFull = true;
+
 	// Move write position back to within buffer
 	if (writePos >= audioBufferSize)
 		writePos -= audioBufferSize;
@@ -308,6 +338,8 @@ void OutputAudio(unsigned numSamples, INT16 *leftBuffer, INT16 *rightBuffer)
 		//printf("Audio buffer over-run #%u in OutputAudio(%u) [writePos = %u, writeWrapped = %s, playPos = %u, audioBufferSize = %u, numBytes = %u]\n",
 		//	overRuns, numSamples, writePos, (writeWrapped ? "true" : "false"), playPos, audioBufferSize, numBytes);
 		
+		halfFull = true;
+
 		// Discard current chunk of data
 		goto Finish;
 	}
@@ -366,6 +398,9 @@ void OutputAudio(unsigned numSamples, INT16 *leftBuffer, INT16 *rightBuffer)
 Finish:
 	// Unlock SDL audio callback
 	SDL_UnlockAudio();
+
+	// Return whether buffer is half full
+	return halfFull;
 }
 
 void CloseAudio()

Src/OSD/SDL/Main.cpp

@@ -762,16 +762,24 @@ int Supermodel(const char *zipFile, CInputs *Inputs, CINIFile *CmdLine)
 			quit = 1;
 		
 #ifdef SUPERMODEL_DEBUGGER
+		bool processUI = true;
 		if (Debugger != NULL)
 		{
 			Debugger->Poll();
 
 			// Check if debugger requests exit or pause
 			if (Debugger->CheckExit())
+			{
 				quit = 1;
+				processUI = false;
+			}
 			else if (Debugger->CheckPause())	
+			{
 				paused = 1;
-			else
+				processUI = false;
+			}
+		}
+		if (processUI)
 		{
 #endif // SUPERMODEL_DEBUGGER
 
@@ -783,6 +791,12 @@ int Supermodel(const char *zipFile, CInputs *Inputs, CINIFile *CmdLine)
 		}
 		else if (Inputs->uiReset->Pressed())
  		{
+			if (!paused)
+			{
+				Model3->PauseThreads();
+				SetAudioEnabled(false);
+			}
+
 			// Reset emulator
 			Model3->Reset();
 			
@@ -792,17 +806,46 @@ int Supermodel(const char *zipFile, CInputs *Inputs, CINIFile *CmdLine)
 				Debugger->Reset();
 #endif // SUPERMODEL_DEBUGGER
 
+			if (!paused)
+			{
+				Model3->ResumeThreads();
+				SetAudioEnabled(true);
+			}
+
 			puts("Model 3 reset.");
 		}
 		else if (Inputs->uiPause->Pressed())
 		{
 			// Toggle emulator paused flag
 			paused = !paused;
+
+			if (paused)
+			{
+				Model3->PauseThreads();
+				SetAudioEnabled(false);
+			}
+			else
+			{
+				Model3->ResumeThreads();
+				SetAudioEnabled(true);
+			}
 		}
 		else if (Inputs->uiSaveState->Pressed())
 		{
+			if (!paused)
+			{
+				Model3->PauseThreads();
+				SetAudioEnabled(false);
+			}
+
 			// Save game state
  			SaveState(Model3);
+
+			if (!paused)
+			{
+				Model3->ResumeThreads();
+				SetAudioEnabled(true);
+			}
 		}
 		else if (Inputs->uiChangeSlot->Pressed())
 		{
@@ -813,6 +856,12 @@ int Supermodel(const char *zipFile, CInputs *Inputs, CINIFile *CmdLine)
 		}
 		else if (Inputs->uiLoadState->Pressed())
 		{
+			if (!paused)
+			{
+				Model3->PauseThreads();
+				SetAudioEnabled(false);
+			}
+
 			// Load game state
 			LoadState(Model3);
 						
@@ -821,6 +870,12 @@ int Supermodel(const char *zipFile, CInputs *Inputs, CINIFile *CmdLine)
 			if (Debugger != NULL)
 				Debugger->Reset();
 #endif // SUPERMODEL_DEBUGGER
+
+			if (!paused)
+			{
+				Model3->ResumeThreads();
+				SetAudioEnabled(true);
+			}
 		}
 		else if (Inputs->uiMusicVolUp->Pressed())
 		{
@@ -904,7 +959,7 @@ int Supermodel(const char *zipFile, CInputs *Inputs, CINIFile *CmdLine)
  			printf("Frame limiting: %s\n", g_Config.throttle?"On":"Off");
  		}
 #ifdef SUPERMODEL_DEBUGGER
-				else if (Inputs->uiEnterDebugger->Pressed())
+			else if (Debugger != NULL && Inputs->uiEnterDebugger->Pressed())
 			{
 				// Break execution and enter debugger
 				Debugger->ForceBreak(true);

Src/OSD/SDL/Thread.cpp

@@ -122,6 +122,11 @@ bool CCondVar::Signal()
 	return SDL_CondSignal((SDL_cond*)m_impl) == 0;
 }
 
+bool CCondVar::SignalAll()
+{
+	return SDL_CondBroadcast((SDL_cond*)m_impl) == 0;
+}
+
 CMutex::CMutex(void *impl) : m_impl(impl)
 {
 	//