From dea1a2fd580849087bd627665d47d4458f044801 Mon Sep 17 00:00:00 2001
From: Sour <mesenemu@gmail.com>
Date: Sat, 4 Feb 2023 15:34:16 -0500
Subject: [PATCH] NES: Fixed NSF playback issues due to incorrect state at
 power on/reset

---
 Core/NES/BaseMapper.h              | 1 +
 Core/NES/Mappers/NSF/NsfMapper.cpp | 7 +++++++
 Core/NES/Mappers/NSF/NsfMapper.h   | 1 +
 Core/NES/NesConsole.cpp            | 2 ++
 4 files changed, 11 insertions(+)

diff --git a/Core/NES/BaseMapper.h b/Core/NES/BaseMapper.h
index f1c55294..0daaa82f 100644
--- a/Core/NES/BaseMapper.h
+++ b/Core/NES/BaseMapper.h
@@ -166,6 +166,7 @@ public:
 
 	virtual ~BaseMapper();
 	virtual void Reset(bool softReset);
+	virtual void OnAfterResetPowerOn() {}
 
 	GameSystem GetGameSystem();
 	PpuModel GetPpuModel();
diff --git a/Core/NES/Mappers/NSF/NsfMapper.cpp b/Core/NES/Mappers/NSF/NsfMapper.cpp
index 2352b0e3..04c1318c 100644
--- a/Core/NES/Mappers/NSF/NsfMapper.cpp
+++ b/Core/NES/Mappers/NSF/NsfMapper.cpp
@@ -88,6 +88,11 @@ void NsfMapper::Reset(bool softReset)
 	if(!softReset) {
 		_songNumber = _nsfHeader.StartingSong - 1;
 	}
+}
+
+void NsfMapper::OnAfterResetPowerOn()
+{
+	//Do this after reset/power on sequence is over, otherwise cpu reset will reset all these values
 
 	//INIT logic
 	NesMemoryManager* mm = _console->GetMemoryManager();
@@ -137,7 +142,9 @@ void NsfMapper::Reset(bool softReset)
 	state.A = _songNumber;
 	state.X = (_nsfHeader.Flags & 0x01) ? 1 : 0; //PAL = 1, NTSC = 0
 	state.Y = 0;
+	state.SP = 0xFD;
 
+	//Disable Frame Counter & DMC interrupts
 	_console->GetCpu()->SetIrqMask((uint8_t)IRQSource::External);
 	_irqCounter = 0;
 
diff --git a/Core/NES/Mappers/NSF/NsfMapper.h b/Core/NES/Mappers/NSF/NsfMapper.h
index ce2a047c..4063198b 100644
--- a/Core/NES/Mappers/NSF/NsfMapper.h
+++ b/Core/NES/Mappers/NSF/NsfMapper.h
@@ -82,6 +82,7 @@ protected:
 	void InitMapper() override;
 	void InitMapper(RomData& romData) override;
 	void Reset(bool softReset) override;
+	void OnAfterResetPowerOn() override;
 	void GetMemoryRanges(MemoryRanges &ranges) override;
 
 	uint32_t GetIrqReloadValue();
diff --git a/Core/NES/NesConsole.cpp b/Core/NES/NesConsole.cpp
index 1100fd14..f893aef8 100644
--- a/Core/NES/NesConsole.cpp
+++ b/Core/NES/NesConsole.cpp
@@ -120,6 +120,7 @@ void NesConsole::Reset()
 	if(_vsSubConsole) {
 		_vsSubConsole->Reset();
 	}
+	_mapper->OnAfterResetPowerOn();
 }
 
 LoadRomResult NesConsole::LoadRom(VirtualFile& romFile)
@@ -190,6 +191,7 @@ LoadRomResult NesConsole::LoadRom(VirtualFile& romFile)
 		_memoryManager->Reset(false);
 		_controlManager->Reset(false);
 		_cpu->Reset(false, _region);
+		_mapper->OnAfterResetPowerOn();
 	}
     return result;
 }