Start moving towards reset being just another style of interrupt.

Signed-off-by: Adrian Conlon <Adrian.conlon@gmail.com>

Intel8080/inc/Intel8080.h

@@ -25,6 +25,7 @@ namespace EightBit {
 		Intel8080(Bus& bus, InputOutput& ports);
 
 		Signal<Intel8080> ExecutingInstruction;
+		Signal<Intel8080> ExecutedInstruction;
 
 		virtual int execute(uint8_t opcode) final;
 		virtual int step() final;
@@ -35,7 +36,8 @@ namespace EightBit {
 		virtual register16_t& HL() final;
 
 	protected:
-		virtual void reset() final;
+		virtual void handleRESET() final;
+		virtual void handleINT() final;
 
 	private:
 		bool m_interruptEnable = false;

Intel8080/src/Intel8080.cpp

@@ -23,9 +23,21 @@ EightBit::register16_t& EightBit::Intel8080::HL() {
 	return hl;
 }
 
-void EightBit::Intel8080::reset() {
+void EightBit::Intel8080::handleRESET() {
-	IntelProcessor::reset();
+	Processor::handleRESET();
 	di();
+	addCycles(3);
+}
+
+
+void EightBit::Intel8080::handleINT() {
+	Processor::handleINT();
+	raise(HALT());
+	if (m_interruptEnable) {
+		di();
+		execute(BUS().DATA());
+	}
+	addCycles(3);
 }
 
 void EightBit::Intel8080::di() {
@@ -258,18 +270,17 @@ int EightBit::Intel8080::step() {
 	ExecutingInstruction.fire(*this);
 	resetCycles();
 	if (LIKELY(powered())) {
-		if (UNLIKELY(lowered(INT()))) {
+		if (UNLIKELY(lowered(RESET()))) {
-			raise(HALT());
+			handleRESET();
-			raise(INT());
+		} else if (UNLIKELY(lowered(INT()))) {
-			if (m_interruptEnable) {
+			handleINT();
-				di();
+		} else if (UNLIKELY(lowered(HALT()))) {
-				return execute(BUS().DATA());
+			execute(0);	// NOP
-			}
+		} else {
+			execute(fetchByte());
 		}
-		if (UNLIKELY(lowered(HALT())))
-			return execute(0);	// NOP
-		return execute(fetchByte());
 	}
+	ExecutedInstruction.fire(*this);
 	return cycles();
 }
 

Intel8080/test/Board.cpp

@@ -18,7 +18,6 @@ void Board::initialise() {
 	m_ram.load(romDirectory + "/8080EX1.COM", 0x100);	// Cringle/Bartholomew
 	//m_ram.load(romDirectory + "/CPUTEST.COM", 0x100);	// SuperSoft diagnostics
 
-	poke(5, 0xc9); // ret
 	m_cpu.ExecutingInstruction.connect(std::bind(&Board::Cpu_ExecutingInstruction_Cpm, this, std::placeholders::_1));
 
 	if (m_configuration.isProfileMode()) {
@@ -30,15 +29,23 @@ void Board::initialise() {
 	}
 
 	CPU().powerOn();
-	CPU().PC() = m_configuration.getStartAddress();
+	CPU().reset();
+
+	poke(0, 0xc3);	// JMP
+	poke(1, m_configuration.getStartAddress().low);
+	poke(2, m_configuration.getStartAddress().high);
+
+	poke(5, 0xc9); // ret
 }
 
 void Board::Cpu_ExecutingInstruction_Cpm(EightBit::Intel8080& cpu) {
 	switch (cpu.PC().word) {
 	case 0x0:	// CP/M warm start
-		CPU().powerOff();
+		if (++m_warmstartCount == 3) {
-		if (m_configuration.isProfileMode()) {
+			CPU().powerOff();
-			m_profiler.dump();
+			if (m_configuration.isProfileMode()) {
+				m_profiler.dump();
+			}
 		}
 		break;
 	case 0x5:	// BDOS

Intel8080/test/Board.h

@@ -31,6 +31,7 @@ private:
 	EightBit::Intel8080 m_cpu;
 	EightBit::Disassembler m_disassembler;
 	EightBit::Profiler m_profiler;
+	int m_warmstartCount = 0;
 
 	void Cpu_ExecutingInstruction_Cpm(EightBit::Intel8080& cpu);
 

LR35902/inc/LR35902.h

@@ -39,8 +39,6 @@ namespace EightBit {
 			virtual register16_t& DE() final { return de; }
 			virtual register16_t& HL() final { return hl; }
 
-			int singleStep();
-
 		protected:
 			virtual void reset() final;
 			virtual int execute(uint8_t opcode) final;

LR35902/src/LR35902.cpp

@@ -277,38 +277,30 @@ void EightBit::GameBoy::LR35902::ccf() {
 	clearFlag(F(), CF, F() & CF);
 }
 
-int EightBit::GameBoy::LR35902::singleStep() {
-
-	const auto interruptEnable = BUS().peek(IoRegisters::BASE + IoRegisters::IE);
-	const auto interruptFlags = m_bus.IO().peek(IoRegisters::IF);
-
-	auto masked = interruptEnable & interruptFlags;
-	if (masked) {
-		if (IME()) {
-			m_bus.IO().poke(IoRegisters::IF, 0);
-			lower(INT());
-			const int index = EightBit::findFirstSet(masked);
-			BUS().DATA() = 0x38 + (index << 3);
-		} else {
-			if (halted())
-				proceed();
-		}
-	}
-
-	const auto current = step();
-
-	m_bus.IO().checkTimers(current);
-	m_bus.IO().transferDma();
-
-	return current;
-}
-
 int EightBit::GameBoy::LR35902::step() {
+
 	ExecutingInstruction.fire(*this);
 	m_prefixCB = false;
 	resetCycles();
 	int ran = 0;
 	if (LIKELY(powered())) {
+
+		const auto interruptEnable = BUS().peek(IoRegisters::BASE + IoRegisters::IE);
+		const auto interruptFlags = m_bus.IO().peek(IoRegisters::IF);
+
+		auto masked = interruptEnable & interruptFlags;
+		if (masked) {
+			if (IME()) {
+				m_bus.IO().poke(IoRegisters::IF, 0);
+				lower(INT());
+				const int index = EightBit::findFirstSet(masked);
+				BUS().DATA() = 0x38 + (index << 3);
+			} else {
+				if (halted())
+					proceed();
+			}
+		}
+
 		if (UNLIKELY(lowered(INT()))) {
 			raise(HALT());
 			raise(INT());
@@ -320,6 +312,10 @@ int EightBit::GameBoy::LR35902::step() {
 		} else {
 			ran = execute(fetchByte());
 		}
+
+		m_bus.IO().checkTimers(ran);
+		m_bus.IO().transferDma();
+
 	}
 	ExecutedInstruction.fire(*this);
 	return ran;

M6502/src/mos6502.cpp

@@ -6,6 +6,8 @@ EightBit::MOS6502::MOS6502(Bus& bus)
 
 void EightBit::MOS6502::powerOn() {
 
+	Processor::powerOn();
+
 	X() = Bit7;
 	Y() = 0;
 	A() = 0;
@@ -13,8 +15,6 @@ void EightBit::MOS6502::powerOn() {
 	S() = Mask8;
 
 	raise(SO());
-
-	Processor::powerOn();
 }
 
 int EightBit::MOS6502::step() {

MC6809/inc/mc6809.h

@@ -74,11 +74,17 @@ namespace EightBit {
 		PinLevel& FIRQ() { return m_firq; }
 
 	protected:
-		virtual void reset() final;
+
+		// Default push/pop handlers
 
 		virtual void push(uint8_t value) final { pushS(value);  }
 		virtual uint8_t pop() final { return popS(); }
 
+		// Interrupt (etc.) handlers
+
+		virtual void handleRESET() final;
+		virtual void handleNMI() final;
+
 	private:
 		const uint8_t RESETvector = 0xfe;		// RESET vector
 		const uint8_t NMIvector = 0xfc;			// NMI vector
@@ -113,8 +119,13 @@ namespace EightBit {
 			return register16_t(low, high);
 		}
 
-		register16_t popWordS() { popWord(S()); }
+		register16_t popWordS() { return popWord(S()); }
-		register16_t popWordU() { popWord(U()); }
+		register16_t popWordU() { return popWord(U()); }
+
+		// Interrupt (etc.) handlers
+
+		void handleIRQ();	
+		void handleFIRQ();
 
 		// Execution helpers
 
@@ -122,12 +133,6 @@ namespace EightBit {
 		void execute10(uint8_t opcode);
 		void execute11(uint8_t opcode);
 
-		// Interrupt handlers
-
-		void handleNMI();
-		void handleIRQ();
-		void handleFIRQ();
-
 		// Register selection for "indexed"
 		register16_t& RR(int which);
 

MC6809/src/mc6809.cpp

@@ -12,7 +12,9 @@ int EightBit::mc6809::step() {
 	if (LIKELY(powered())) {
 		m_prefix10 = m_prefix11 = false;
 		ExecutingInstruction.fire(*this);
-		if (lowered(NMI()))
+		if (lowered(RESET()))
+			handleRESET();
+		else if (lowered(NMI()))
 			handleNMI();
 		else if (lowered(FIRQ()) && !(CC() & FF))
 			handleFIRQ();
@@ -27,36 +29,37 @@ int EightBit::mc6809::step() {
 
 // Interrupt (etc.) handlers
 
-void EightBit::mc6809::reset() {
+void EightBit::mc6809::handleRESET() {
-	Processor::reset();
+	Processor::handleRESET();
-	DP() = 0;	// Reestablish zero page
+	raise(NMI());
-	setFlag(CC(), IF | FF);	// Disable IRQ and FIRQ
+	DP() = 0;
+	setFlag(CC(), IF | FF);
 	jump(getWordPaged(0xff, RESETvector));
 }
 
 void EightBit::mc6809::handleNMI() {
-	raise(NMI());
+	Processor::handleNMI();
-	addCycles(21);
 	saveEntireRegisterState();
 	jump(getWordPaged(0xff, NMIvector));
+	addCycles(21);
 }
 
 void EightBit::mc6809::handleIRQ() {
-	raise(IRQ());
+	Processor::handleINT();	// Synonymous
-	addCycles(21);
 	saveEntireRegisterState();
-	setFlag(CC(), IF);	// Disable IRQ
+	setFlag(CC(), IF);
 	jump(getWordPaged(0xff, IRQvector));
+	addCycles(21);
 }
 
 void EightBit::mc6809::handleFIRQ() {
-	addCycles(12);
 	raise(FIRQ());
-	clearFlag(CC(), EF);	// Clear the EF flag. i.e. this only saves PC and CC
+	clearFlag(CC(), EF);
 	pushWordS(PC());
 	pushS(CC());
-	setFlag(CC(), IF | FF);	// Disable IRQ and FIRQ
+	setFlag(CC(), IF | FF);
 	jump(getWordPaged(0xff, FIRQvector));
+	addCycles(12);
 }
 
 //

Z80/inc/Z80.h

@@ -49,11 +49,13 @@ namespace EightBit {
 		Z80(Bus& bus, InputOutput& ports);
 
 		Signal<Z80> ExecutingInstruction;
+		Signal<Z80> ExecutedInstruction;
 
 		PinLevel& M1() { return m_m1Line; }			// Out
 
 		virtual int execute(uint8_t opcode) final;
 		virtual int step() final;
+		virtual void powerOn() final;
 
 		virtual register16_t& AF() final;
 		virtual register16_t& BC() final;
@@ -83,7 +85,9 @@ namespace EightBit {
 		}
 
 	protected:
-		virtual void reset() final;
+		virtual void handleRESET() final;
+		virtual void handleNMI() final;
+		virtual void handleINT() final;
 
 	private:
 		PinLevel m_m1Line = Low;

Z80/src/Z80.cpp

@@ -24,9 +24,9 @@ EightBit::register16_t& EightBit::Z80::HL() {
 	return m_registers[m_registerSet][HL_IDX];
 }
 
-void EightBit::Z80::reset() {
+void EightBit::Z80::powerOn() {
 
-	IntelProcessor::reset();
+	IntelProcessor::powerOn();
 
 	raise(M1());
 
@@ -34,23 +34,53 @@ void EightBit::Z80::reset() {
 	IM() = 0;
 
 	REFRESH() = 0;
-	IV() = 0xff;
+	IV() = Mask8;
 
 	exxAF();
 	exx();
 
-	AF() = 0xffff;
+	IX() = IY() = AF() = BC() = DE() = HL() = Mask16;
-
-	BC() = 0xffff;
-	DE() = 0xffff;
-	HL() = 0xffff;
-
-	IX() = 0xffff;
-	IY() = 0xffff;
 
 	m_prefixCB = m_prefixDD = m_prefixED = m_prefixFD = false;
 }
 
+void EightBit::Z80::handleRESET() {
+	Processor::handleRESET();
+	di();
+	addCycles(3);
+}
+
+void EightBit::Z80::handleNMI() {
+	Processor::handleNMI();
+	raise(HALT());
+	IFF1() = false;
+	restart(0x66);
+	addCycles(13);
+}
+
+void EightBit::Z80::handleINT() {
+	Processor::handleINT();
+	raise(HALT());
+	if (IFF1()) {
+		di();
+		switch (IM()) {
+		case 0:		// i8080 equivalent
+			execute(BUS().DATA());
+			break;
+		case 1:
+			restart(7 << 3);
+			addCycles(13);
+			break;
+		case 2:
+			call(MEMPTR() = register16_t(BUS().DATA(), IV()));
+			addCycles(19);
+			break;
+		default:
+			UNREACHABLE;
+		}
+	}
+}
+
 void EightBit::Z80::di() {
 	IFF1() = IFF2() = false;
 }
@@ -614,39 +644,19 @@ int EightBit::Z80::step() {
 	resetCycles();
 	if (LIKELY(powered())) {
 		lower(M1());
-		if (UNLIKELY(lowered(NMI()))) {
+		if (UNLIKELY(lowered(RESET()))) {
-			raise(HALT());
+			handleRESET();
-			raise(NMI());
+		} else if (UNLIKELY(lowered(NMI()))) {
-			IFF1() = false;
+			handleNMI();
-			restart(0x66);
+		} else if (UNLIKELY(lowered(INT()))) {
-			addCycles(13);
+			handleINT();
-			return cycles();
+		} else if (UNLIKELY(lowered(HALT()))) {
+			execute(0);	// NOP
+		} else {
+			execute(fetchByte());
 		}
-		if (UNLIKELY(lowered(INT()))) {
-			raise(HALT());
-			raise(INT());
-			if (IFF1()) {
-				di();
-				switch (IM()) {
-				case 0:		// i8080 equivalent
-					return execute(BUS().DATA());
-				case 1:
-					restart(7 << 3);
-					addCycles(13);
-					return cycles();
-				case 2:
-					call(MEMPTR() = register16_t(BUS().DATA(), IV()));
-					addCycles(19);
-					return cycles();
-				default:
-					UNREACHABLE;
-				}
-			}
-		}
-		if (UNLIKELY(lowered(HALT())))
-			return execute(0);	// NOP
-		return execute(fetchByte());
 	}
+	ExecutedInstruction.fire(*this);
 	return cycles();
 }
 

Z80/test/Board.cpp

@@ -18,7 +18,6 @@ void Board::initialise() {
 	m_ram.load(romDirectory + "/zexall.com", 0x100);	// Cringle/Bartholomew
 	//m_ram.load(romDirectory + "/CPUTEST.COM", 0x100);	// SuperSoft diagnostics
 
-	poke(5, 0xc9);	// ret
 	m_cpu.ExecutingInstruction.connect(std::bind(&Board::Cpu_ExecutingInstruction_Cpm, this, std::placeholders::_1));
 
 	if (m_configuration.isProfileMode()) {
@@ -30,7 +29,13 @@ void Board::initialise() {
 	}
 
 	CPU().powerOn();
-	CPU().PC() = m_configuration.getStartAddress();
+	CPU().reset();
+
+	poke(0, 0xc3);	// JMP
+	poke(1, m_configuration.getStartAddress().low);
+	poke(2, m_configuration.getStartAddress().high);
+
+	poke(5, 0xc9);	// ret
 }
 
 void Board::Cpu_ExecutingInstruction_Cpm(EightBit::Z80& cpu) {
@@ -38,9 +43,11 @@ void Board::Cpu_ExecutingInstruction_Cpm(EightBit::Z80& cpu) {
 		CPU().powerOff();
 	switch (cpu.PC().word) {
 	case 0x0:	// CP/M warm start
-		CPU().powerOff();
+		if (++m_warmstartCount == 3) {
-		if (m_configuration.isProfileMode()) {
+			CPU().powerOff();
-			m_profiler.dump();
+			if (m_configuration.isProfileMode()) {
+				m_profiler.dump();
+			}
 		}
 		break;
 	case 0x5:	// BDOS

Z80/test/Board.h

@@ -32,6 +32,7 @@ private:
 	EightBit::Z80 m_cpu;
 	EightBit::Disassembler m_disassembler;
 	EightBit::Profiler m_profiler;
+	int m_warmstartCount = 0;
 
 	void Cpu_ExecutingInstruction_Cpm(EightBit::Z80& cpu);
 

inc/IntelProcessor.h

@@ -56,12 +56,12 @@ namespace EightBit {
 		uint8_t& H() { return HL().high; }
 		uint8_t& L() { return HL().low; }
 
+		virtual void powerOn() override;
+
 	protected:
 		IntelProcessor(Bus& bus);
 		virtual ~IntelProcessor() = default;
 
-		virtual void reset() override;
-
 		template<class T> static void adjustSign(uint8_t& f, const uint8_t value) {
 			setFlag(f, T::SF, value & T::SF);
 		}

inc/Processor.h

@@ -78,11 +78,11 @@ namespace EightBit {
 		PinLevel& POWER() { return m_powerLine; }
 
 		bool powered() { return raised(POWER()); }
-		virtual void powerOn() { raise(POWER()); raise(HALT()); reset(); }
+		virtual void powerOn();
 		void powerOff() { lower(POWER()); }
+		void reset() { lower(RESET()); }
 
 		int run(int limit);
-		virtual int singleStep();
 		virtual int step() = 0;
 
 		virtual int execute(uint8_t opcode) = 0;
@@ -102,12 +102,14 @@ namespace EightBit {
 		Processor(Bus& memory);
 		virtual ~Processor() = default;
 
-		virtual void reset();
-
 		bool halted() { return lowered(HALT()); }
 		void halt() { --PC();  lower(HALT()); }
 		void proceed() { ++PC(); raise(HALT()); }
 
+		virtual void handleRESET();
+		virtual void handleNMI();
+		virtual void handleINT();
+
 		uint8_t getBytePaged(uint8_t page, uint8_t offset) {
 			return BUS().read(register16_t(offset, page));
 		}

src/IntelProcessor.cpp

@@ -7,8 +7,8 @@ EightBit::IntelProcessor::IntelProcessor(Bus& bus)
 		m_decodedOpcodes[i] = i;
 }
 
-void EightBit::IntelProcessor::reset() {
+void EightBit::IntelProcessor::powerOn() {
-	Processor::reset();
+	Processor::powerOn();
 	SP() = AF() = BC() = DE() = HL() = Mask16;
 }
 

src/Processor.cpp

@@ -5,24 +5,30 @@ EightBit::Processor::Processor(Bus& bus)
 : m_bus(bus) {
 }
 
-void EightBit::Processor::reset() {
+void EightBit::Processor::powerOn() {
-	if (lowered(POWER()))
+	raise(RESET());
-		throw std::logic_error("POWER cannot be low");
+	raise(HALT());
 	raise(INT());
 	raise(NMI());
+	raise(POWER());
+}
+
+void EightBit::Processor::handleRESET() {
 	raise(RESET());
 	PC() = 0;
 }
 
+void EightBit::Processor::handleNMI() {
+	raise(NMI());
+}
+
+void EightBit::Processor::handleINT() {
+	raise(INT());
+}
+
 int EightBit::Processor::run(const int limit) {
 	int current = 0;
 	while (LIKELY(powered()) && current < limit)
-		current += singleStep();
+		current += step();
 	return current;
 }
-
-int EightBit::Processor::singleStep() {
-	if (UNLIKELY(lowered(RESET())))
-		reset();
-	return step();
-}