Support overclocking and underclocking the Gamecube CPU

Won't work with all games, but provides a nice way to spend extra CPU to make
a variable framerate game faster (e.g. Spyro or The Last Story), or to make
a game use less CPU at the cost of a lower framerate (e.g. Rogue Leader).

Source/Core/Common/StringUtil.h

@@ -64,6 +64,8 @@ template <typename N>
 static bool TryParse(const std::string &str, N *const output)
 {
 	std::istringstream iss(str);
+	// is this right? not doing this breaks reading floats on locales that use different decimal separators
+	iss.imbue(std::locale(".1252"));
 
 	N tmp = 0;
 	if (iss >> tmp)

Source/Core/Core/BootManager.cpp

@@ -250,6 +250,8 @@ bool BootCore(const std::string& _rFilename)
 		StartUp.bEnableMemcardSaving = g_NetPlaySettings.m_WriteToMemcard;
 		StartUp.iCPUCore = g_NetPlaySettings.m_CPUcore;
 		SConfig::GetInstance().m_DSPEnableJIT = g_NetPlaySettings.m_DSPEnableJIT;
+		SConfig::GetInstance().m_OCEnable = g_NetPlaySettings.m_OCEnable;
+		SConfig::GetInstance().m_OCFactor = g_NetPlaySettings.m_OCFactor;
 		SConfig::GetInstance().m_EXIDevice[0] = g_NetPlaySettings.m_EXIDevice[0];
 		SConfig::GetInstance().m_EXIDevice[1] = g_NetPlaySettings.m_EXIDevice[1];
 		config_cache.bSetEXIDevice[0] = true;

Source/Core/Core/ConfigManager.cpp

@@ -345,6 +345,8 @@ void SConfig::SaveCoreSettings(IniFile& ini)
 	core->Set("RunCompareClient", m_LocalCoreStartupParameter.bRunCompareClient);
 	core->Set("FrameLimit", m_Framelimit);
 	core->Set("FrameSkip", m_FrameSkip);
+	core->Set("Overclock", m_OCFactor);
+	core->Set("OverclockEnable", m_OCEnable);
 	core->Set("GFXBackend", m_LocalCoreStartupParameter.m_strVideoBackend);
 	core->Set("GPUDeterminismMode", m_LocalCoreStartupParameter.m_strGPUDeterminismMode);
 	core->Set("GameCubeAdapter", m_GameCubeAdapter);
@@ -580,6 +582,8 @@ void SConfig::LoadCoreSettings(IniFile& ini)
 	core->Get("FastDiscSpeed",             &m_LocalCoreStartupParameter.bFastDiscSpeed,    false);
 	core->Get("DCBZ",                      &m_LocalCoreStartupParameter.bDCBZOFF,          false);
 	core->Get("FrameLimit",                &m_Framelimit,                                  1); // auto frame limit by default
+	core->Get("Overclock",                 &m_OCFactor,                                    1.0f);
+	core->Get("OverclockEnable",           &m_OCEnable,                                    false);
 	core->Get("FrameSkip",                 &m_FrameSkip,                                   0);
 	core->Get("GFXBackend",                &m_LocalCoreStartupParameter.m_strVideoBackend, "");
 	core->Get("GPUDeterminismMode",        &m_LocalCoreStartupParameter.m_strGPUDeterminismMode, "auto");

Source/Core/Core/ConfigManager.h

@@ -49,6 +49,8 @@ struct SConfig : NonCopyable
 	int m_InterfaceLanguage;
 	// framelimit choose
 	unsigned int m_Framelimit;
+	bool m_OCEnable;
+	float m_OCFactor;
 	// other interface settings
 	bool m_InterfaceToolbar;
 	bool m_InterfaceStatusbar;

Source/Core/Core/Core.cpp

@@ -327,6 +327,8 @@ void EmuThread()
 
 	Common::SetCurrentThreadName("Emuthread - Starting");
 
+	if (SConfig::GetInstance().m_OCEnable)
+		DisplayMessage("WARNING: running at non-native CPU clock! Game may not be stable.", 8000);
 	DisplayMessage(cpu_info.brand_string, 8000);
 	DisplayMessage(cpu_info.Summarize(), 8000);
 	DisplayMessage(core_parameter.m_strFilename, 3000);

Source/Core/Core/CoreTiming.cpp

@@ -48,6 +48,7 @@ static Common::FifoQueue<BaseEvent, false> tsQueue;
 // event pools
 static Event *eventPool = nullptr;
 
+float lastOCFactor;
 int slicelength;
 static int maxSliceLength = MAX_SLICE_LENGTH;
 
@@ -82,6 +83,23 @@ static void FreeEvent(Event* ev)
 
 static void EmptyTimedCallback(u64 userdata, int cyclesLate) {}
 
+// Changing the CPU speed in Dolphin isn't actually done by changing the physical clock rate,
+// but by changing the amount of work done in a particular amount of time. This tends to be more
+// compatible because it stops the games from actually knowing directly that the clock rate has
+// changed, and ensures that anything based on waiting a specific number of cycles still works.
+//
+// Technically it might be more accurate to call this changing the IPC instead of the CPU speed,
+// but the effect is largely the same.
+static int DowncountToCycles(int downcount)
+{
+	return (int)(downcount / lastOCFactor);
+}
+
+static int CyclesToDowncount(int cycles)
+{
+	return (int)(cycles * lastOCFactor);
+}
+
 int RegisterEvent(const std::string& name, TimedCallback callback)
 {
 	EventType type;
@@ -115,7 +133,8 @@ void UnregisterAllEvents()
 
 void Init()
 {
-	PowerPC::ppcState.downcount = maxSliceLength;
+	lastOCFactor = SConfig::GetInstance().m_OCEnable ? SConfig::GetInstance().m_OCFactor : 1.0f;
+	PowerPC::ppcState.downcount = CyclesToDowncount(maxSliceLength);
 	slicelength = maxSliceLength;
 	globalTimer = 0;
 	idledCycles = 0;
@@ -182,6 +201,7 @@ void DoState(PointerWrap &p)
 	p.Do(fakeDecStartTicks);
 	p.Do(fakeTBStartValue);
 	p.Do(fakeTBStartTicks);
+	p.Do(lastOCFactor);
 	p.DoMarker("CoreTimingData");
 
 	MoveEvents();
@@ -338,10 +358,10 @@ void SetMaximumSlice(int maximumSliceLength)
 
 void ForceExceptionCheck(int cycles)
 {
-	if (PowerPC::ppcState.downcount > cycles)
+	if (DowncountToCycles(PowerPC::ppcState.downcount) > cycles)
 	{
-		slicelength -= (PowerPC::ppcState.downcount - cycles); // Account for cycles already executed by adjusting the slicelength
+		slicelength -= (DowncountToCycles(PowerPC::ppcState.downcount) - cycles); // Account for cycles already executed by adjusting the slicelength
-		PowerPC::ppcState.downcount = cycles;
+		PowerPC::ppcState.downcount = CyclesToDowncount(cycles);
 	}
 }
 
@@ -392,9 +412,10 @@ void Advance()
 {
 	MoveEvents();
 
-	int cyclesExecuted = slicelength - PowerPC::ppcState.downcount;
+	int cyclesExecuted = slicelength - DowncountToCycles(PowerPC::ppcState.downcount);
 	globalTimer += cyclesExecuted;
-	PowerPC::ppcState.downcount = slicelength;
+	lastOCFactor = SConfig::GetInstance().m_OCEnable ? SConfig::GetInstance().m_OCFactor : 1.0f;
+	PowerPC::ppcState.downcount = CyclesToDowncount(slicelength);
 
 	while (first)
 	{
@@ -416,14 +437,14 @@ void Advance()
 	if (!first)
 	{
 		WARN_LOG(POWERPC, "WARNING - no events in queue. Setting downcount to 10000");
-		PowerPC::ppcState.downcount += 10000;
+		PowerPC::ppcState.downcount += CyclesToDowncount(10000);
 	}
 	else
 	{
 		slicelength = (int)(first->time - globalTimer);
 		if (slicelength > maxSliceLength)
 			slicelength = maxSliceLength;
-		PowerPC::ppcState.downcount = slicelength;
+		PowerPC::ppcState.downcount = CyclesToDowncount(slicelength);
 	}
 
 	if (advanceCallback)
@@ -456,7 +477,7 @@ void Idle()
 		}
 	}
 
-	idledCycles += PowerPC::ppcState.downcount;
+	idledCycles += DowncountToCycles(PowerPC::ppcState.downcount);
 	PowerPC::ppcState.downcount = 0;
 
 	Advance();

Source/Core/Core/NetPlayClient.cpp

@@ -250,6 +250,8 @@ unsigned int NetPlayClient::OnData(sf::Packet& packet)
 			packet >> g_NetPlaySettings.m_DSPEnableJIT;
 			packet >> g_NetPlaySettings.m_DSPHLE;
 			packet >> g_NetPlaySettings.m_WriteToMemcard;
+			packet >> g_NetPlaySettings.m_OCEnable;
+			packet >> g_NetPlaySettings.m_OCFactor;
 			int tmp;
 			packet >> tmp;
 			g_NetPlaySettings.m_EXIDevice[0] = (TEXIDevices) tmp;

Source/Core/Core/NetPlayProto.h

@@ -16,6 +16,8 @@ struct NetSettings
 	bool m_DSPHLE;
 	bool m_DSPEnableJIT;
 	bool m_WriteToMemcard;
+	bool m_OCEnable;
+	float m_OCFactor;
 	TEXIDevices m_EXIDevice[2];
 };
 

Source/Core/Core/NetPlayServer.cpp

@@ -554,6 +554,8 @@ bool NetPlayServer::StartGame()
 	spac << m_settings.m_DSPEnableJIT;
 	spac << m_settings.m_DSPHLE;
 	spac << m_settings.m_WriteToMemcard;
+	spac << m_settings.m_OCEnable;
+	spac << m_settings.m_OCFactor;
 	spac << m_settings.m_EXIDevice[0];
 	spac << m_settings.m_EXIDevice[1];
 

Source/Core/DolphinWX/ConfigMain.cpp

@@ -134,7 +134,8 @@ EVT_CHOICE(ID_FRAMELIMIT, CConfigMain::CoreSettingsChanged)
 
 EVT_RADIOBOX(ID_CPUENGINE, CConfigMain::CoreSettingsChanged)
 EVT_CHECKBOX(ID_NTSCJ, CConfigMain::CoreSettingsChanged)
-
+EVT_SLIDER(ID_OVERCLOCK, CConfigMain::CoreSettingsChanged)
+EVT_CHECKBOX(ID_ENABLEOVERCLOCK, CConfigMain::CoreSettingsChanged)
 
 EVT_RADIOBOX(ID_DSPENGINE, CConfigMain::AudioSettingsChanged)
 EVT_CHECKBOX(ID_ENABLE_THROTTLE, CConfigMain::AudioSettingsChanged)
@@ -327,6 +328,10 @@ void CConfigMain::InitializeGUIValues()
 	SkipIdle->SetValue(startup_params.bSkipIdle);
 	EnableCheats->SetValue(startup_params.bEnableCheats);
 	Framelimit->SetSelection(SConfig::GetInstance().m_Framelimit);
+	int ocFactor = (int)(log2f(SConfig::GetInstance().m_OCFactor) * 25.f + 100.f + 0.5f);
+	EnableOC->SetValue(SConfig::GetInstance().m_OCEnable);
+	OCSlider->SetValue(ocFactor);
+	UpdateCPUClock();
 
 	// General - Advanced
 	for (unsigned int a = 0; a < (sizeof(CPUCores) / sizeof(CPUCore)); ++a)
@@ -497,6 +502,7 @@ void CConfigMain::CreateGUIControls()
 	wxPanel* const AudioPage = new wxPanel(Notebook, ID_AUDIOPAGE);
 	wxPanel* const GamecubePage = new wxPanel(Notebook, ID_GAMECUBEPAGE);
 	wxPanel* const WiiPage = new wxPanel(Notebook, ID_WIIPAGE);
+	wxPanel* const AdvancedPage = new wxPanel(Notebook, ID_ADVANCEDPAGE);
 	PathsPage = new wxPanel(Notebook, ID_PATHSPAGE);
 
 	Notebook->AddPage(GeneralPage, _("General"));
@@ -505,6 +511,7 @@ void CConfigMain::CreateGUIControls()
 	Notebook->AddPage(GamecubePage, _("GameCube"));
 	Notebook->AddPage(WiiPage, _("Wii"));
 	Notebook->AddPage(PathsPage, _("Paths"));
+	Notebook->AddPage(AdvancedPage, _("Advanced"));
 
 	// General page
 	// Core Settings - Basic
@@ -521,6 +528,7 @@ void CConfigMain::CreateGUIControls()
 	wxBoxSizer* sFramelimit = new wxBoxSizer(wxHORIZONTAL);
 	sFramelimit->Add(TEXT_BOX(GeneralPage, _("Framelimit:")), 0, wxALIGN_CENTER_VERTICAL | wxLEFT | wxRIGHT | wxBOTTOM, 5);
 	sFramelimit->Add(Framelimit, 0, wxLEFT | wxRIGHT | wxBOTTOM | wxEXPAND, 5);
+
 	wxStaticBoxSizer* const sbBasic = new wxStaticBoxSizer(wxVERTICAL, GeneralPage, _("Basic Settings"));
 	sbBasic->Add(CPUThread, 0, wxALL, 5);
 	sbBasic->Add(SkipIdle, 0, wxALL, 5);
@@ -782,6 +790,33 @@ void CConfigMain::CreateGUIControls()
 	sMain->Add(Notebook, 1, wxEXPAND|wxALL, 5);
 	sMain->Add(CreateButtonSizer(wxOK), 0, wxEXPAND | wxLEFT | wxRIGHT | wxBOTTOM, 5);
 
+	wxStaticBoxSizer* sbCPUOptions = new wxStaticBoxSizer(wxVERTICAL, AdvancedPage, _("CPU Options"));
+	wxBoxSizer* bOverclockEnable = new wxBoxSizer(wxHORIZONTAL);
+	wxBoxSizer* bOverclock = new wxBoxSizer(wxHORIZONTAL);
+	wxBoxSizer* bOverclockDesc = new wxBoxSizer(wxHORIZONTAL);
+	EnableOC = new wxCheckBox(AdvancedPage, ID_ENABLEOVERCLOCK, _("Enable CPU Clock Override"));
+	OCSlider = new wxSlider(AdvancedPage, ID_OVERCLOCK, 100, 0, 150, wxDefaultPosition, wxDefaultSize, wxSL_HORIZONTAL);
+	wxStaticText* OCDescription = new wxStaticText(AdvancedPage, wxID_ANY,
+	  _("Higher values can make variable-framerate games\n"
+	    "run at a higher framerate, at the expense of CPU.\n"
+	    "Lower values can make variable-framerate games\n"
+	    "run at a lower framerate, saving CPU.\n\n"
+	    "WARNING: Changing this from the default (100%)\n"
+	    "can and will break games and cause glitches.\n"
+	    "Do so at your own risk. Please do not report\n"
+	    "bugs that occur with a non-default clock.\n"));
+	OCText = new wxStaticText(AdvancedPage, wxID_ANY, "");
+	bOverclockEnable->Add(EnableOC);
+	bOverclock->Add(OCSlider, 1, wxALL, 5);
+	bOverclock->Add(OCText, 1, wxALL, 5);
+	bOverclockDesc->Add(OCDescription, 1, wxALL, 5);
+	sbCPUOptions->Add(bOverclockEnable);
+	sbCPUOptions->Add(bOverclock);
+	sbCPUOptions->Add(bOverclockDesc);
+	wxBoxSizer* const sAdvancedPage = new wxBoxSizer(wxVERTICAL);
+	sAdvancedPage->Add(sbCPUOptions, 0, wxEXPAND | wxALL, 5);
+	AdvancedPage->SetSizer(sAdvancedPage);
+
 	InitializeGUIValues();
 	InitializeGUITooltips();
 
@@ -805,6 +840,14 @@ void CConfigMain::OnOk(wxCommandEvent& WXUNUSED (event))
 	SConfig::GetInstance().SaveSettings();
 }
 
+void CConfigMain::UpdateCPUClock()
+{
+	bool wii = SConfig::GetInstance().m_LocalCoreStartupParameter.bWii;
+	int percent = (int)(roundf(SConfig::GetInstance().m_OCFactor * 100.f));
+	int clock = (int)(roundf(SConfig::GetInstance().m_OCFactor * (wii ? 729.f : 486.f)));
+	OCText->SetLabel(SConfig::GetInstance().m_OCEnable ? wxString::Format("%d %% (%d mhz)", percent, clock) : "");
+}
+
 // Core settings
 void CConfigMain::CoreSettingsChanged(wxCommandEvent& event)
 {
@@ -839,6 +882,16 @@ void CConfigMain::CoreSettingsChanged(wxCommandEvent& event)
 	case ID_NTSCJ:
 		startup_params.bForceNTSCJ = _NTSCJ->IsChecked();
 		break;
+	case ID_ENABLEOVERCLOCK:
+		SConfig::GetInstance().m_OCEnable = EnableOC->IsChecked();
+		OCSlider->Enable(SConfig::GetInstance().m_OCEnable);
+		UpdateCPUClock();
+		break;
+	case ID_OVERCLOCK:
+		// Vaguely exponential scaling?
+		SConfig::GetInstance().m_OCFactor = exp2f((OCSlider->GetValue() - 100.f) / 25.f);
+		UpdateCPUClock();
+		break;
 	}
 }
 

Source/Core/DolphinWX/ConfigMain.h

@@ -69,6 +69,7 @@ public:
 		ID_GAMECUBEPAGE,
 		ID_WIIPAGE,
 		ID_PATHSPAGE,
+		ID_ADVANCEDPAGE,
 	};
 
 private:
@@ -77,7 +78,9 @@ private:
 		ID_CPUTHREAD = 1010,
 		ID_IDLESKIP,
 		ID_ENABLECHEATS,
+		ID_ENABLEOVERCLOCK,
 		ID_FRAMELIMIT,
+		ID_OVERCLOCK,
 
 		ID_CPUENGINE,
 
@@ -144,6 +147,9 @@ private:
 	// Advanced
 	wxRadioBox* CPUEngine;
 	wxCheckBox* _NTSCJ;
+	wxSlider* OCSlider;
+	wxStaticText* OCText;
+	wxCheckBox* EnableOC;
 
 
 	wxBoxSizer* sDisplayPage; // Display settings
@@ -238,6 +244,7 @@ private:
 	void UpdateGUI();
 	void OnClose(wxCloseEvent& event);
 
+	void UpdateCPUClock();
 	void CoreSettingsChanged(wxCommandEvent& event);
 
 	void DisplaySettingsChanged(wxCommandEvent& event);

Source/Core/DolphinWX/NetWindow.cpp

@@ -438,6 +438,8 @@ void NetPlayDiag::GetNetSettings(NetSettings &settings)
 	settings.m_DSPHLE = instance.m_LocalCoreStartupParameter.bDSPHLE;
 	settings.m_DSPEnableJIT = instance.m_DSPEnableJIT;
 	settings.m_WriteToMemcard = m_memcard_write->GetValue();
+	settings.m_OCEnable = instance.m_OCEnable;
+	settings.m_OCFactor = instance.m_OCFactor;
 	settings.m_EXIDevice[0] = instance.m_EXIDevice[0];
 	settings.m_EXIDevice[1] = instance.m_EXIDevice[1];
 }