From 0fe4091f27bec2f0fa34b6e679d3239de9adfbd6 Mon Sep 17 00:00:00 2001
From: Souryo <mesenemu@gmail.com>
Date: Wed, 25 Jun 2014 13:30:02 -0400
Subject: [PATCH] Fixed reset state for CPU (to pass test roms)

---
 Core/CPU.cpp     | 26 ++++++++++++++++----------
 Core/CPU.h       |  2 +-
 Core/Console.cpp |  8 ++++----
 Core/Console.h   |  2 +-
 4 files changed, 22 insertions(+), 16 deletions(-)

diff --git a/Core/CPU.cpp b/Core/CPU.cpp
index b4b33a0d..3ba80969 100644
--- a/Core/CPU.cpp
+++ b/Core/CPU.cpp
@@ -71,20 +71,26 @@ CPU::CPU(MemoryManager *memoryManager) : _memoryManager(memoryManager)
 	memcpy(_cyclesPageCrossed, cyclesPageCrossed, sizeof(uint8_t) * 256);
 }
 
-void CPU::Reset()
+void CPU::Reset(bool softReset)
 {
 	CPU::NMIFlag = false;
 	CPU::IRQFlag = 0;
 	CPU::CycleCount = 0;
-	_state.A = 0;
-	_state.PC = MemoryReadWord(0xFFFC);
-	_state.SP = 0xFF;
-	_state.X = 0;
-	_state.Y = 0;
-	_state.PS = PSFlags::Zero | PSFlags::Reserved | PSFlags::Interrupt;
 
-	_runIRQ = false;
-	_runNMI = false;
+	_state.PC = MemoryReadWord(CPU::ResetVector);
+	if(softReset) {
+		SetFlags(PSFlags::Interrupt);
+		_state.SP -= 0x03;
+	} else {
+		_state.A = 0;
+		_state.SP = 0xFD;
+		_state.X = 0;
+		_state.Y = 0;
+		_state.PS = PSFlags::Reserved | PSFlags::Interrupt;
+
+		_runIRQ = false;
+		_runNMI = false;
+	}
 }
 
 uint32_t CPU::Exec()
@@ -111,7 +117,7 @@ uint32_t CPU::Exec()
 
 		if(!_runIRQ && opCode == 0x40 && CPU::IRQFlag > 0 && !CheckFlag(PSFlags::Interrupt)) {
 			//"If an IRQ is pending and an RTI is executed that clears the I flag, the CPU will invoke the IRQ handler immediately after RTI finishes executing."
-			//_runIRQ = true;
+			_runIRQ = true;
 		}
 	} else {
 		if(_runNMI) {
diff --git a/Core/CPU.h b/Core/CPU.h
index 977ae403..611dbf58 100644
--- a/Core/CPU.h
+++ b/Core/CPU.h
@@ -657,7 +657,7 @@ public:
 		CPU::IRQFlag &= ~(int)source;
 	}
 
-	void Reset();
+	void Reset(bool softReset);
 	uint32_t Exec();
 	State GetState() { return _state; }
 
diff --git a/Core/Console.cpp b/Core/Console.cpp
index e9f0c440..8a66619d 100644
--- a/Core/Console.cpp
+++ b/Core/Console.cpp
@@ -23,7 +23,7 @@ Console::Console(wstring filename)
 	_memoryManager->RegisterIODevice(_apu.get());
 	_memoryManager->RegisterIODevice(_controlManager.get());
 
-	ResetComponents();
+	ResetComponents(false);
 }
 
 Console::~Console()
@@ -35,9 +35,9 @@ void Console::Reset()
 	_reset = true;
 }
 
-void Console::ResetComponents()
+void Console::ResetComponents(bool softReset)
 {
-	_cpu->Reset();
+	_cpu->Reset(softReset);
 	_ppu->Reset();
 	_apu->Reset();
 }
@@ -108,7 +108,7 @@ void Console::Run()
 			fpsTimer.Reset();
 			lastFrameCount = 0;
 			elapsedTime = 0;
-			ResetComponents();
+			ResetComponents(true);
 			_reset = false;
 		}
 	}
diff --git a/Core/Console.h b/Core/Console.h
index 8367bb2c..c0feae65 100644
--- a/Core/Console.h
+++ b/Core/Console.h
@@ -31,7 +31,7 @@ class Console
 		bool _stop = false;
 		bool _reset = false;
 
-		void ResetComponents();
+		void ResetComponents(bool softReset);
 
 	public:
 		Console(wstring filename);