PPU, NMI

Core/CPU.cpp

@@ -3,6 +3,7 @@
 #include "Timer.h"
 
 uint64_t CPU::CycleCount = 0;
+bool CPU::NMIFlag = false;
 
 CPU::CPU(MemoryManager *memoryManager) : _memoryManager(memoryManager)
 {
@@ -63,11 +64,17 @@ void CPU::Reset()
 
 void CPU::Exec()
 {
-	uint8_t opCode = ReadByte();
+	if(!CPU::NMIFlag) {
-	if(_opTable[opCode] != nullptr) {
+		uint8_t opCode = ReadByte();
-		(this->*_opTable[opCode])();
+		if(_opTable[opCode] != nullptr) {
-		CPU::CycleCount += this->_cycles[opCode];
+			(this->*_opTable[opCode])();
+			CPU::CycleCount += this->_cycles[opCode];
+		} else {
+			//throw std::exception("Invalid opcode");
+		}
 	} else {
-		//throw std::exception("Invalid opcode");
+		NMI();
+		CPU::CycleCount += 7;
+		CPU::NMIFlag = false;
 	}
 }

Core/CPU.h

@@ -41,6 +41,7 @@ private:
 	MemoryManager *_memoryManager = nullptr;
 
 	static uint64_t CycleCount;
+	static bool NMIFlag;
 
 	uint16_t _currentPC = 0;
 	uint8_t _cyclePenalty = 0;
@@ -592,6 +593,14 @@ private:
 		SetPC(MemoryReadWord(0xFFFE));
 	}
 
+	void NMI() {
+		Push((uint16_t)(PC() + 1));
+		Push((uint8_t)PS());
+		SetFlags(PSFlags::Interrupt);
+		SetPC(MemoryReadWord(0xFFFA));
+	}
+
+
 	void NOP() {}
 	void RTI() {
 		SetPS(Pop());
@@ -601,13 +610,10 @@ private:
 
 public:
 	CPU(MemoryManager *memoryManager);
-	static uint64_t GetCycleCount() {
+	static uint64_t GetCycleCount() { return CPU::CycleCount; }
-		return CPU::CycleCount;
+	static void SetNMIFlag() { CPU::NMIFlag = true; }
-	}
 	void Reset();
 	void Exec();
-	State GetState()
+	State GetState() { return _state; }
-	{
+
-		return _state;
-	}
 };

Core/Console.cpp

@@ -12,7 +12,7 @@ Console::Console(string filename)
 
 Console::~Console()
 {
-
+	_cpu.release();
 }
 
 void Console::Reset()
@@ -46,7 +46,7 @@ void Console::RunTests()
 	console->Run();
 	delete console;*/
 
-	vector<std::string> testROMs = { { "nestest", "01-basics", "02-implied", "03-immediate", "04-zero_page", "05-zp_xy", "06-absolute", "07-abs_xy", "08-ind_x", "09-ind_y", "10-branches", "11-stack", "12-jmp_jsr", "13-rts", "14-rti", "15-brk", "16-special" } };
+	vector<std::string> testROMs = { { "01-basics", "02-implied", "03-immediate", "04-zero_page", "05-zp_xy", "06-absolute", "07-abs_xy", "08-ind_x", "09-ind_y", "10-branches", "11-stack", "12-jmp_jsr", "13-rts", "14-rti", "15-brk", "16-special" } };
 
 	for(string testROM : testROMs) {
 		Console *console = new Console(string("TestSuite/") + testROM + ".nes");
@@ -64,7 +64,7 @@ void Console::RunTests()
 				uint8_t testStatus = console->_memoryManager.Read(0x6000);
 				if(testStatus == 0x81) {
 					//need reset
-					throw std::exception("reset needed");
+					OutputDebugStringA("reset needed");
 				} else if(testStatus == 0x80) {
 					testStarted = true;
 				} else if(testStatus < 0x80 && testStarted) {

Core/PPU.cpp

@@ -5,7 +5,9 @@
 PPU::PPU() 
 {
 	_state = {};
-	
+	_flags = {};
+	_statusFlags = {};
+
 	_outputBuffer = new uint8_t[256 * 240 * 4];
 }
 
@@ -105,7 +107,8 @@ void PPU::UpdateStatusFlag()
 {
 	_state.Status = ((uint8_t)_statusFlags.SpriteOverflow << 5) |
 						 ((uint8_t)_statusFlags.Sprite0Hit << 6) |
-						 ((uint8_t)_statusFlags.VerticalBlank << 7));
+						 ((uint8_t)_statusFlags.VerticalBlank << 7);
+	_statusFlags.VerticalBlank = false;
 }
 
 void PPU::Exec()
@@ -113,14 +116,19 @@ void PPU::Exec()
 	uint64_t equivalentCycleCount = CPU::GetCycleCount() * 3;
 	while(_cycleCount < equivalentCycleCount) {
 		if(_scanline == -1) {
+			//Pre-render scanline
 			if(_cycle == 1) {
 				_statusFlags.SpriteOverflow = false;
 				_statusFlags.Sprite0Hit = false;
+				_statusFlags.VerticalBlank = false;
 			} else if(_cycle == 304) {
 				// Copy scroll latch into VRAMADDR register
-				if(_flags.BackgroundEnabled || _flags.SpritesEnabled) {
+				/*if(_flags.BackgroundEnabled || _flags.SpritesEnabled) {
 					//p->registers.vramAddress = p->registers.vramLatch;
-				}
+				}*/
+			} else if(_cycle == 339 && (_frameCount % 2 == 1)) {
+				//Skip a cycle for odd frames
+				_cycle++;
 			}
 		} else if(_scanline < 240) {
 			if(_cycle == 254) {
@@ -136,38 +144,42 @@ void PPU::Exec()
 					//Ppu_updateEndScanlineRegisters(p);
 				}
 			}
-		} else if(_scanline == 240) {
+		} else if(_scanline == 241) {
+			//Start of VBlank
 			if(_cycle == 1) {
-				if(!_suppressVBlank) {
+				_statusFlags.VerticalBlank = true;
+				/*if(!_suppressVBlank) {
 					// We're in VBlank
 					Ppu_setStatus(p, STATUS_VBLANK_STARTED);
 					p->cycleCount = 0;
+				}*/
+				if(_flags.VBlank) {
+					CPU::SetNMIFlag();
 				}
-				if(_flags.VBlank && !_suppressNMI) {
+				/*if(_flags.VBlank && !_suppressNMI) {
 					VBlankInterrupt();
-				}
+				}*/
 				//Ppu_raster(p);
 			}
 		} else if(_scanline == 260) {
-			// End of vblank
+			//End of VBlank
-			if(_cycle == 1) {
+			if(_cycle == 340) {
-				// Clear VBlank flag
-				Ppu_clearStatus(p, STATUS_VBLANK_STARTED);
-				_cycleCount = 0;
-			} else if(_cycle == 341) {
-				_scanline = -1;
-				_cycle = 1;
 				_frameCount++;
-				return;
 			}
 		}
 
-		if(_cycle == 341) {
+		if(_cycle == 340) {
 			_cycle = 0;
 			_scanline++;
+
+			if(_scanline == 261) {
+				_scanline = -1;
+				_frameCount++;
+			}
+		} else {
+			_cycle++;
 		}
 
-		_cycle++;
 		_cycleCount++;
 	}
 }

Core/PPU.h

@@ -64,9 +64,10 @@ class PPU : public IMemoryHandler
 
 		int16_t _scanline = -1;
 		uint16_t _cycle = 0;
+		uint32_t _frameCount = 0;
 
-		PPUControlFlags _flags = {};
+		PPUControlFlags _flags;
-		PPUStatusFlags _statusFlags = {};
+		PPUStatusFlags _statusFlags;
 
 		void PPU::UpdateStatusFlag();