From 7e4a141b7ba7b6890ab03ad647aa9e58a55edddc Mon Sep 17 00:00:00 2001
From: Sour <mesenemu@gmail.com>
Date: Fri, 29 Mar 2019 22:13:22 -0400
Subject: [PATCH] SPC: Fixed potential overflow problem when running for a very
 long time

---
 Core/Console.cpp |  2 +-
 Core/Spc.cpp     | 13 ++++++++-----
 Core/Spc.h       |  3 +++
 3 files changed, 12 insertions(+), 6 deletions(-)

diff --git a/Core/Console.cpp b/Core/Console.cpp
index 602c6d2..345b520 100644
--- a/Core/Console.cpp
+++ b/Core/Console.cpp
@@ -230,10 +230,10 @@ bool Console::LoadRom(VirtualFile romFile, VirtualFile patchFile, bool stopRom)
 
 		_internalRegisters.reset(new InternalRegisters(shared_from_this()));
 		_ppu.reset(new Ppu(shared_from_this()));
-		_spc.reset(new Spc(shared_from_this(), spcRomData));
 		_controlManager.reset(new ControlManager(shared_from_this()));
 		_memoryManager.reset(new MemoryManager());
 		_dmaController.reset(new DmaController(_memoryManager.get()));
+		_spc.reset(new Spc(shared_from_this(), spcRomData));
 
 		_memoryManager->Initialize(shared_from_this());
 
diff --git a/Core/Spc.cpp b/Core/Spc.cpp
index ae91d60..2881925 100644
--- a/Core/Spc.cpp
+++ b/Core/Spc.cpp
@@ -9,6 +9,7 @@
 Spc::Spc(shared_ptr<Console> console, vector<uint8_t> &spcRomData)
 {
 	_console = console;
+	_memoryManager = console->GetMemoryManager();
 	_soundBuffer = new int16_t[Spc::SampleBufferSize];
 	_immediateMode = false;
 	_operandA = 0;
@@ -28,6 +29,8 @@ Spc::Spc(shared_ptr<Console> console, vector<uint8_t> &spcRomData)
 	_state.RomEnabled = true;
 	_state.SP = 0xFF;
 	_state.PC = ReadWord(Spc::ResetVector);
+
+	_clockRatio = (double)2048000 / _console->GetMasterClockRate();
 }
 
 Spc::~Spc()
@@ -202,9 +205,7 @@ void Spc::CpuWriteRegister(uint32_t addr, uint8_t value)
 
 void Spc::Run()
 {
-	int64_t masterClock = _console->GetMemoryManager()->GetMasterClock();
-	//TODO: This will overflow after 100+ hours, needs to be fixed
-	uint64_t targetCycle = (masterClock * (uint64_t)1024000 / (uint64_t)_console->GetMasterClockRate()) * 2;
+	uint64_t targetCycle = (uint64_t)(_memoryManager->GetMasterClock() * _clockRatio);
 	while(_state.Cycle < targetCycle) {
 		Exec();
 	}
@@ -214,6 +215,8 @@ void Spc::ProcessEndFrame()
 {
 	Run();
 
+	_clockRatio = (double)2048000 / _console->GetMasterClockRate();
+
 	int sampleCount = _dsp->sample_count();
 	if(sampleCount != 0) {
 		_console->GetSoundMixer()->PlayAudioBuffer(_soundBuffer, sampleCount / 2);
@@ -233,14 +236,14 @@ void Spc::Serialize(Serializer &s)
 	s.Stream(_state.OutputReg[0], _state.OutputReg[1], _state.OutputReg[2], _state.OutputReg[3]);
 	s.Stream(_state.RamReg[0], _state.RamReg[1]);
 	s.Stream(_state.ExternalSpeed, _state.InternalSpeed, _state.WriteEnabled, _state.TimersEnabled);
-	s.Stream(_state.DspReg, _state.RomEnabled);
+	s.Stream(_state.DspReg, _state.RomEnabled, _clockRatio);
 
 	_state.Timer0.Serialize(s);
 	_state.Timer1.Serialize(s);
 	_state.Timer2.Serialize(s);
 
 	ArrayInfo<uint8_t> ram { _ram, Spc::SpcRamSize };
-	s.Stream(ram, _state.DspReg, _state.RomEnabled);
+	s.Stream(ram);
 
 	uint8_t dspState[SPC_DSP::state_size];
 	memset(dspState, 0, SPC_DSP::state_size);
diff --git a/Core/Spc.h b/Core/Spc.h
index d8adf94..98e5294 100644
--- a/Core/Spc.h
+++ b/Core/Spc.h
@@ -6,6 +6,7 @@
 #include "../Utilities/ISerializable.h"
 
 class Console;
+class MemoryManager;
 class SPC_DSP;
 
 class Spc : public ISerializable
@@ -18,11 +19,13 @@ private:
 	static constexpr uint16_t ResetVector = 0xFFFE;
 
 	shared_ptr<Console> _console;
+	shared_ptr<MemoryManager> _memoryManager;
 	unique_ptr<SPC_DSP> _dsp;
 
 	bool _immediateMode;
 	uint16_t _operandA;
 	uint16_t _operandB;
+	double _clockRatio;
 
 	SpcState _state;
 	uint8_t _ram[Spc::SpcRamSize];