Implement enough changes to build LR35902

2024-06-02 13:41:33 +00:00 · 2017-06-09 10:23:51 +01:00 · 2017-06-09 10:23:51 +01:00 · f3fe475d44
commit f3fe475d44
parent 1c0fb41027
11 changed files with 567 additions and 64 deletions
--- a/LR35902/inc/Bus.h
+++ b/LR35902/inc/Bus.h
@ -0,0 +1,106 @@
+#pragma once
+
+#include "Memory.h"
+
+class Bus : public EightBit::Memory {
+public:
+
+	enum {
+		TotalLineCount = 154
+	};
+
+	enum {
+		VideoRam = 0x8000
+	};
+
+	enum {
+
+		BASE = 0xFF00,
+
+		// Port/Mode Registers
+		P1 = 0x0,
+		SB = 0x1,
+		SC = 0x2,
+		DIV = 0x4,
+		TIMA = 0x5,
+		TMA = 0x6,
+		TAC = 0x7,
+
+		// Interrupt Flags
+		IF = 0xF,
+		IE = 0xFF,
+
+		// LCD Display Registers
+		LCDC = 0x40,
+		STAT = 0x41,
+		SCY = 0x42,
+		SCX = 0x43,
+		LY = 0x44,
+		LYC = 0x45,
+		DMA = 0x46,
+		BGP = 0x47,
+		OBP0 = 0x48,
+		OBP1 = 0x49,
+		WY = 0x4A,
+		WX = 0x4B,
+
+		// Sound Registers
+		NR10 = 0x10,
+		NR11 = 0x11,
+		NR12 = 0x12,
+		NR13 = 0x13,
+		NR14 = 0x14,
+		NR21 = 0x16,
+		NR22 = 0x17,
+		NR23 = 0x18,
+		NR24 = 0x19,
+		NR30 = 0x1A,
+		NR31 = 0x1B,
+		NR32 = 0x1C,
+		NR33 = 0x1D,
+		NR34 = 0x1E,
+		NR41 = 0x20,
+		NR42 = 0x21,
+		NR43 = 0x22,
+		NR44 = 0x23,
+		NR50 = 0x24,
+		NR51 = 0x25,
+		NR52 = 0x26,
+
+		WPRAM_START = 0x30,
+		WPRAM_END = 0x3F,
+
+		// Boot rom control
+		BOOT_DISABLE = 0x50,
+	};
+
+	Bus();
+
+	void reset();
+
+	uint8_t& REG(int offset) {
+		ADDRESS().word = BASE + offset;
+		return Memory::reference();
+	}
+
+	void incrementLY() {
+		REG(LY) = (REG(LY) + 1) % TotalLineCount;
+	}
+
+	void resetLY() {
+		REG(LY) = 0;
+	}
+
+	void loadBootRom(const std::string& path);
+
+	bool isBootRom(uint16_t address) const {
+		return (address < m_boot.size()) && (peek(BASE + BOOT_DISABLE) == 0);
+	}
+
+	virtual uint8_t peek(uint16_t address) const;
+
+	virtual uint8_t& reference();
+
+private:
+	std::array<uint8_t, 0x100> m_boot;
+};
--- a/LR35902/inc/LR35902.h
+++ b/LR35902/inc/LR35902.h
@ -3,8 +3,9 @@
 #include <cstdint>

 #include "Processor.h"
+#include "Bus.h"

-class LR35902 : public Processor {
+class LR35902 : public EightBit::Processor {
 public:
 	enum StatusBits {
 		ZF = Bit7,
@ -15,7 +16,7 @@ public:

 	LR35902(Bus& memory);

-	Signal<LR35902> ExecutingInstruction;
+	EightBit::Signal<LR35902> ExecutingInstruction;

 	void stop() { m_stopped = true; }
 	void start() { m_stopped = false; }
@ -33,7 +34,7 @@ public:

 	// Mutable access to processor!!

-	register16_t& AF() {
+	EightBit::register16_t& AF() {
 		m_accumulatorFlag.low &= 0xf0;
 		return m_accumulatorFlag;
 	}
@ -41,21 +42,21 @@ public:
 	uint8_t& A() { return AF().high; }
 	uint8_t& F() { return AF().low; }

-	register16_t& BC() {
+	EightBit::register16_t& BC() {
 		return m_registers[BC_IDX];
 	}

 	uint8_t& B() { return BC().high; }
 	uint8_t& C() { return BC().low; }

-	register16_t& DE() {
+	EightBit::register16_t& DE() {
 		return m_registers[DE_IDX];
 	}

 	uint8_t& D() { return DE().high; }
 	uint8_t& E() { return DE().low; }

-	register16_t& HL() {
+	EightBit::register16_t& HL() {
 		return m_registers[HL_IDX];
 	}

@ -68,8 +69,8 @@ public:
 private:
 	enum { BC_IDX, DE_IDX, HL_IDX };

-	std::array<register16_t, 3> m_registers;
-	register16_t m_accumulatorFlag;
+	std::array<EightBit::register16_t, 3> m_registers;
+	EightBit::register16_t m_accumulatorFlag;

 	bool m_ime;

@ -80,6 +81,12 @@ private:
 	std::array<bool, 8> m_halfCarryTableAdd = { { false, false, true, false, true, false, true, true } };
 	std::array<bool, 8> m_halfCarryTableSub = { { false, true, true, true, false, false, false, true } };

+	EightBit::register16_t fetchWord() {
+		EightBit::register16_t returned;
+		Processor::fetchWord(returned);
+		return returned;
+	}
+
 	int fetchExecute() {
 		return execute(fetchByte());
 	}
@ -110,28 +117,29 @@ private:
 		case 5:
 			return L();
 		case 6:
-			return m_memory.reference(HL().word);
+			m_memory.ADDRESS() = HL();
+			return m_memory.reference();
 		case 7:
 			return A();
 		}
 		throw std::logic_error("Unhandled registry mechanism");
 	}

-	uint16_t& RP(int rp) {
+	EightBit::register16_t& RP(int rp) {
 		switch (rp) {
 		case 3:
 			return sp;
 		default:
-			return m_registers[rp].word;
+			return m_registers[rp];
 		}
 	}

-	uint16_t& RP2(int rp) {
+	EightBit::register16_t& RP2(int rp) {
 		switch (rp) {
 		case 3:
-			return AF().word;
+			return AF();
 		default:
-			return m_registers[rp].word;
+			return m_registers[rp];
 		}
 	}

--- a/LR35902/inc/StatusFlags.h
+++ b/LR35902/inc/StatusFlags.h
@ -0,0 +1,83 @@
+#pragma once
+
+#include <string>
+#include <cstdint>
+
+struct StatusFlags {
+
+	bool SF;
+	bool ZF;
+	bool YF;
+	bool HF;
+	bool XF;
+	bool PF;
+	bool NF;
+	bool CF;
+
+	enum StatusBits {
+		Sign = 0x80,				// SF
+		Zero = 0x40,				// ZF
+		YFlag = 0x20,				// YF
+		HalfCarry = 0x10,			// HC
+		XFlag= 0x8,					// XF
+		Parity = 0x4,				// PF
+		Overflow = 0x4,				// PF
+		Subtract = 0x2,				// NF
+		Carry = 0x1,				// CF
+	};
+
+	StatusFlags(uint8_t value = 0) {
+		SF = (value & StatusBits::Sign) != 0;
+		ZF = (value & StatusBits::Zero) != 0;
+		YF = (value & StatusBits::YFlag) != 0;
+		HF = (value & StatusBits::HalfCarry) != 0;
+		XF = (value & StatusBits::XFlag) != 0;
+		PF = (value & StatusBits::Parity) != 0;		// parity/overflow
+		NF = (value & StatusBits::Subtract) != 0;
+		CF = (value & StatusBits::Carry) != 0;
+	}
+
+	operator uint8_t() const {
+
+		uint8_t flags = 0;
+
+		if (SF)
+			flags |= StatusBits::Sign;
+
+		if (ZF)
+			flags |= StatusBits::Zero;
+
+		if (YF)
+			flags |= StatusBits::YFlag;
+
+		if (HF)
+			flags |= StatusBits::HalfCarry;
+
+		if (XF)
+			flags |= StatusBits::XFlag;
+
+		if (PF)
+			flags |= StatusBits::Parity;
+
+		if (NF)
+			flags |= StatusBits::Subtract;
+
+		if (CF)
+			flags |= StatusBits::Carry;
+
+		return flags;
+	}
+
+	operator std::string() const {
+		std::string returned;
+		returned += SF ? "S" : "-";
+		returned += ZF ? "Z" : "-";
+		returned += YF ? "Y" : "-";
+		returned += HF ? "H" : "-";
+		returned += XF ? "X" : "-";
+		returned += PF ? "P" : "-";
+		returned += NF ? "N" : "-";
+		returned += CF ? "C" : "-";
+		return returned;
+	}
+};
--- a/LR35902/src/Bus.cpp
+++ b/LR35902/src/Bus.cpp
@ -0,0 +1,32 @@
+#include "stdafx.h"
+#include "Bus.h"
+
+Bus::Bus()
+: Memory(0xffff) {
+}
+
+void Bus::reset() {
+	REG(NR52) = 0xf1;
+	REG(LCDC) = 0x91;
+}
+
+void Bus::loadBootRom(const std::string& path) {
+	auto size = loadMemory(path, 0);
+	if (size != 0x100)
+		throw std::runtime_error("Incorrectly sized boot ROM");
+	std::copy_n(m_bus.cbegin(), size, m_boot.begin());
+}
+
+uint8_t& Bus::reference() {
+	auto effective = effectiveAddress(ADDRESS().word);
+	if (isBootRom(effective))
+		return placeDATA(m_boot[effective]);
+	return Memory::reference();
+}
+
+uint8_t Bus::peek(uint16_t address) const {
+	auto effective = effectiveAddress(address);
+	if (isBootRom(effective))
+		return m_boot[effective];
+	return m_bus[effective];
+}
--- a/LR35902/src/Disassembler.cpp
+++ b/LR35902/src/Disassembler.cpp
@ -34,9 +34,9 @@ std::string Disassembler::state(LR35902& cpu) {
 	std::ostringstream output;

 	output
-		<< "PC=" << hex(pc)
+		<< "PC=" << hex(pc.word)
 		<< " "
-		<< "SP=" << hex(sp)
+		<< "SP=" << hex(sp.word)
 		<< " " << "A=" << hex(a) << " " << "F=" << flags(f)
 		<< " " << "B=" << hex(b) << " " << "C=" << hex(c)
 		<< " " << "D=" << hex(d) << " " << "E=" << hex(e)
@ -142,7 +142,7 @@ std::string Disassembler::alu(int which) {
 std::string Disassembler::disassemble(LR35902& cpu) {
 	m_prefixCB = false;
 	std::ostringstream output;
-	disassemble(output, cpu, cpu.getProgramCounter());
+	disassemble(output, cpu, cpu.getProgramCounter().word);
 	return output.str();
 }

@ -162,7 +162,7 @@ void Disassembler::disassemble(std::ostringstream& output, LR35902& cpu, uint16_
 	auto q = (y & 1);

 	auto immediate = memory.peek(pc + 1);
-	auto absolute = cpu.getWord(pc + 1);
+	auto absolute = memory.peekWord(pc + 1);
 	auto displacement = (int8_t)immediate;
 	auto relative = pc + displacement + 2;
 	auto indexedImmediate = memory.peek(pc + 1);
@ -517,10 +517,10 @@ std::string Disassembler::flags(uint8_t value) {
 		<< flag(value, LR35902::NF, "N")
 		<< flag(value, LR35902::HC, "H")
 		<< flag(value, LR35902::CF, "C")
-		<< flag(value, Processor::Bit3, "+")
-		<< flag(value, Processor::Bit2, "+")
-		<< flag(value, Processor::Bit1, "+")
-		<< flag(value, Processor::Bit0, "+");
+		<< flag(value, EightBit::Processor::Bit3, "+")
+		<< flag(value, EightBit::Processor::Bit2, "+")
+		<< flag(value, EightBit::Processor::Bit1, "+")
+		<< flag(value, EightBit::Processor::Bit0, "+");
 		return output.str();
 }

--- a/LR35902/src/LR35902.cpp
+++ b/LR35902/src/LR35902.cpp
@ -12,7 +12,7 @@ LR35902::LR35902(Bus& memory)

 void LR35902::reset() {
 	Processor::reset();
-	setStackPointer(0xfffe);
+	sp.word = 0xfffe;
 	di();
 }

@ -60,13 +60,13 @@ void LR35902::postDecrement(uint8_t value) {

 void LR35902::restart(uint8_t address) {
 	pushWord(pc);
-	pc = address;
+	pc.word = address;
 }

 void LR35902::jrConditional(int conditional) {
 	auto offset = (int8_t)fetchByte();
 	if (conditional) {
-		pc += offset;
+		pc.word += offset;
 		cycles++;
 	}
 }
@ -121,22 +121,25 @@ void LR35902::jumpConditionalFlag(int flag) {
 		cycles--; // Giving 8 cycles
 		break;
 	case 5:	// GB: LD (nn),A
-		m_memory.set(fetchWord(), A());
+		m_memory.ADDRESS() = fetchWord();
+		m_memory.reference() = A();
 		cycles++; // Giving 16 cycles
 		break;
 	case 6:	// GB: LD A,(FF00 + C)
-		A() = m_memory.get(0xff00 + C());
+		m_memory.ADDRESS().word = 0xff00 + C();
+		A() = m_memory.reference();
 		cycles--; // 8 cycles
 		break;
 	case 7:	// GB: LD A,(nn)
-		A() = m_memory.get(fetchWord());
+		m_memory.ADDRESS() = fetchWord();
+		A() = m_memory.reference();
 		cycles++; // Giving 16 cycles
 		break;
 	}
 }

 void LR35902::ret() {
-	pc = popWord();
+	popWord(pc);
 }

 void LR35902::reti() {
@ -172,10 +175,10 @@ void LR35902::returnConditionalFlag(int flag) {
 	case 5: { // GB: ADD SP,dd
 			auto before = sp;
 			auto value = fetchByte();
-			sp += (int8_t)value;
+			sp.word += (int8_t)value;
 			clearFlag(ZF | NF);
-			setFlag(CF, sp & Bit16);
-			adjustHalfCarryAdd(Memory::highByte(before), value, Memory::highByte(sp));
+			setFlag(CF, sp.word & Bit16);
+			adjustHalfCarryAdd(before.high, value, sp.high);
 		}
 		cycles += 2;	// 16 cycles
 		break;
@ -186,11 +189,10 @@ void LR35902::returnConditionalFlag(int flag) {
 	case 7: { // GB: LD HL,SP + dd
 			auto before = sp;
 			auto value = fetchByte();
-			uint16_t result = before + (int8_t)value;
-			HL().word = result;
+			HL().word = before.word + (int8_t)value;
 			clearFlag(ZF | NF);
-			setFlag(CF, result & Bit16);
-			adjustHalfCarryAdd(Memory::highByte(before), value, Memory::highByte(result));
+			setFlag(CF, HL().word & Bit16);
+			adjustHalfCarryAdd(before.high, value, HL().high);
 		}
 		cycles++;	// 12 cycles
 		break;
@ -198,16 +200,14 @@ void LR35902::returnConditionalFlag(int flag) {
 }

 void LR35902::call(uint16_t address) {
-	pushWord(pc + 2);
-	pc = address;
+	pushWord(pc);
+	pc.word = address;
 }

 void LR35902::callConditional(uint16_t address, int condition) {
 	if (condition) {
 		call(address);
 		cycles += 3;
-	} else {
-		pc += 2;
 	}
 }

@ -238,14 +238,14 @@ uint16_t LR35902::sbc(uint16_t value) {

 	auto hl = RP(HL_IDX);

-	auto high = Memory::highByte(hl);
-	auto highValue = Memory::highByte(value);
+	auto high = hl.high;
+	auto highValue = EightBit::Memory::highByte(value);
 	auto applyCarry = F() & CF;

-	uint32_t result = (int)hl - (int)value;
+	uint32_t result = (int)hl.word - (int)value;
 	if (applyCarry)
 		--result;
-	auto highResult = Memory::highByte(result);
+	auto highResult = EightBit::Memory::highByte(result);

 	adjustZero(result);
 	adjustHalfCarrySub(high, highValue, highResult);
@ -260,14 +260,14 @@ uint16_t LR35902::adc(uint16_t value) {

 	auto hl = RP(HL_IDX);

-	auto high = Memory::highByte(hl);
-	auto highValue = Memory::highByte(value);
+	auto high = hl.high;
+	auto highValue = EightBit::Memory::highByte(value);
 	auto applyCarry = F() & CF;

-	uint32_t result = (int)hl + (int)value;
+	uint32_t result = (int)hl.word + (int)value;
 	if (applyCarry)
 		++result;
-	auto highResult = Memory::highByte(result);
+	auto highResult = EightBit::Memory::highByte(result);

 	adjustZero(result);
 	adjustHalfCarryAdd(high, highValue, highResult);
@ -282,12 +282,12 @@ uint16_t LR35902::add(uint16_t value) {

 	auto hl = RP(HL_IDX);

-	auto high = Memory::highByte(hl);
-	auto highValue = Memory::highByte(value);
+	auto high = hl.high;
+	auto highValue = EightBit::Memory::highByte(value);

-	uint32_t result = (int)hl + (int)value;
+	uint32_t result = (int)hl.word + (int)value;

-	auto highResult = Memory::highByte(result);
+	auto highResult = EightBit::Memory::highByte(result);

 	clearFlag(NF);
 	setFlag(CF, result & Bit16);
@ -304,7 +304,7 @@ void LR35902::sub(uint8_t& operand, uint8_t value, bool carry) {
 	if (carry && (F() & CF))
 		--result;

-	operand = Memory::lowByte(result);
+	operand = EightBit::Memory::lowByte(result);

 	adjustZero(operand);
 	adjustHalfCarrySub(before, value, result);
@ -328,7 +328,7 @@ void LR35902::add(uint8_t& operand, uint8_t value, bool carry) {
 	if (carry && (F() & CF))
 		++result;

-	operand = Memory::lowByte(result);
+	operand = EightBit::Memory::lowByte(result);

 	adjustZero(operand);
 	adjustHalfCarryAdd(before, value, result);
@ -625,7 +625,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
 				cycles++;
 				break;
 			case 1:	// GB: LD (nn),SP
-				m_memory.setWord(fetchWord(), sp);
+				m_memory.setWord(fetchWord().word, sp);
 				cycles += 5;
 				break;
 			case 2:	// GB: STOP
@ -649,7 +649,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
 				cycles += 3;
 				break;
 			case 1:	// ADD HL,rp
-				RP(HL_IDX) = add(RP(p));
+				RP(HL_IDX).word = add(RP(p).word);
 				cycles += 2;
 				break;
 			}
@ -701,10 +701,10 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
 		case 3:	// 16-bit INC/DEC
 			switch (q) {
 			case 0:	// INC rp
-				++RP(p);
+				++RP(p).word;
 				break;
 			case 1:	// DEC rp
-				--RP(p);
+				--RP(p).word;
 				break;
 			}
 			cycles += 2;
@ -806,7 +806,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
 		case 1:	// POP & various ops
 			switch (q) {
 			case 0:	// POP rp2[p]
-				RP2(p) = popWord();
+				popWord(RP2(p));
 				cycles += 3;
 				break;
 			case 1:
@ -820,11 +820,11 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
 					cycles += 4;
 					break;
 				case 2:	// JP HL
-					pc = HL().word;
+					pc = HL();
 					cycles += 1;
 					break;
 				case 3:	// LD SP,HL
-					sp = HL().word;
+					sp = HL();
 					cycles += 2;
 					break;
 				}
@ -855,7 +855,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
 			}
 			break;
 		case 4:	// Conditional call: CALL cc[y], nn
-			callConditionalFlag(getWord(pc), y);
+			callConditionalFlag(fetchWord().word, y);
 			cycles += 3;
 			break;
 		case 5:	// PUSH & various ops
@ -867,7 +867,7 @@ void LR35902::executeOther(int x, int y, int z, int p, int q) {
 			case 1:
 				switch (p) {
 				case 0:	// CALL nn
-					callConditional(getWord(pc), true);
+					callConditional(fetchWord().word, true);
 					cycles += 3;
 					break;
 				}
--- a/LR35902/src/LR35902.vcxproj
+++ b/LR35902/src/LR35902.vcxproj
@ -0,0 +1,166 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project DefaultTargets="Build" ToolsVersion="14.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup Label="ProjectConfigurations">
+    <ProjectConfiguration Include="Debug|Win32">
+      <Configuration>Debug</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|Win32">
+      <Configuration>Release</Configuration>
+      <Platform>Win32</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Debug|x64">
+      <Configuration>Debug</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+    <ProjectConfiguration Include="Release|x64">
+      <Configuration>Release</Configuration>
+      <Platform>x64</Platform>
+    </ProjectConfiguration>
+  </ItemGroup>
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>{7730ECF5-8206-4ECB-BA6B-6B5CFE50CFB2}</ProjectGuid>
+    <Keyword>Win32Proj</Keyword>
+    <RootNamespace>LR35902</RootNamespace>
+    <WindowsTargetPlatformVersion>8.1</WindowsTargetPlatformVersion>
+  </PropertyGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.Default.props" />
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v140</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|Win32'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>false</UseDebugLibraries>
+    <PlatformToolset>v140</PlatformToolset>
+    <WholeProgramOptimization>true</WholeProgramOptimization>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Debug|x64'" Label="Configuration">
+    <ConfigurationType>StaticLibrary</ConfigurationType>
+    <UseDebugLibraries>true</UseDebugLibraries>
+    <PlatformToolset>v140</PlatformToolset>
+    <CharacterSet>Unicode</CharacterSet>
+  </PropertyGroup>
+  <PropertyGroup Condition="'$(Configuration)|$(Platform)'=='Release|x64'" Label="Configuration">
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+    <IncludePath>..\inc;..\..\inc;C:\local\boost_1_64_0;C:\local\SDL2-2.0.5\include;$(IncludePath)</IncludePath>
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+    <IncludePath>..\inc;..\..\inc;C:\local\boost_1_64_0;C:\local\SDL2-2.0.5\include;$(IncludePath)</IncludePath>
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+    <ClInclude Include="..\inc\Disassembler.h" />
+    <ClInclude Include="..\inc\LR35902.h" />
+    <ClInclude Include="..\inc\Profiler.h" />
+    <ClInclude Include="stdafx.h" />
+    <ClInclude Include="targetver.h" />
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+    <ClCompile Include="Bus.cpp" />
+    <ClCompile Include="Disassembler.cpp" />
+    <ClCompile Include="LR35902.cpp" />
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+    </ClCompile>
+  </ItemGroup>
+  <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />
+  <ImportGroup Label="ExtensionTargets">
+  </ImportGroup>
+</Project>
--- a/LR35902/src/LR35902.vcxproj.filters
+++ b/LR35902/src/LR35902.vcxproj.filters
@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="Source Files">
+      <UniqueIdentifier>{4FC737F1-C7A5-4376-A066-2A32D752A2FF}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+    <Filter Include="Header Files">
+      <UniqueIdentifier>{93995380-89BD-4b04-88EB-625FBE52EBFB}</UniqueIdentifier>
+      <Extensions>h;hh;hpp;hxx;hm;inl;inc;xsd</Extensions>
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+    <Filter Include="Resource Files">
+      <UniqueIdentifier>{67DA6AB6-F800-4c08-8B7A-83BB121AAD01}</UniqueIdentifier>
+      <Extensions>rc;ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe;resx;tiff;tif;png;wav;mfcribbon-ms</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <Text Include="ReadMe.txt" />
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="stdafx.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="targetver.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="..\inc\Disassembler.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="..\inc\LR35902.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="..\inc\Profiler.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="..\inc\Bus.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
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+    <ClCompile Include="stdafx.cpp">
+      <Filter>Source Files</Filter>
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+    <ClCompile Include="Disassembler.cpp">
+      <Filter>Source Files</Filter>
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+    <ClCompile Include="LR35902.cpp">
+      <Filter>Source Files</Filter>
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+    <ClCompile Include="Profiler.cpp">
+      <Filter>Source Files</Filter>
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+    <ClCompile Include="Bus.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+  </ItemGroup>
+</Project>
--- a/LR35902/src/stdafx.cpp
+++ b/LR35902/src/stdafx.cpp
@ -0,0 +1 @@
+#include "stdafx.h"
--- a/LR35902/src/stdafx.h
+++ b/LR35902/src/stdafx.h
@ -0,0 +1,37 @@
+#pragma once
+
+#include <cstdint>
+#include <stdexcept>
+
+#include <functional>
+
+#include <vector>
+#include <array>
+#include <map>
+
+#include <bitset>
+#include <string>
+
+#include <algorithm>
+
+#include <iostream>
+#include <fstream>
+#include <sstream>
+#include <iomanip>
+
+#include <boost/format.hpp>
+
+#include <SDL.h>
+
+#if SDL_BYTEORDER == SDL_LIL_ENDIAN
+#define HOST_LITTLE_ENDIAN
+#endif
+
+#if SDL_BYTEORDER == SDL_BIG_ENDIAN
+#define HOST_BIG_ENDIAN
+#endif
+
+#ifdef _MSC_VER
+#pragma comment(lib, "SDL2.lib")
+#pragma comment(lib, "SDL2main.lib")
+#endif
--- a/inc/Memory.h
+++ b/inc/Memory.h
@ -28,6 +28,15 @@ namespace EightBit {

 	class Memory {
 	public:
+
+		static uint8_t highByte(uint16_t value) {
+			return value >> 8;
+		}
+
+		static uint8_t lowByte(uint16_t value) {
+			return value & 0xff;
+		}
+
 		Memory(uint16_t addressMask);

 		virtual register16_t& ADDRESS() { return m_address; }
@ -62,10 +71,14 @@ namespace EightBit {
 		virtual void setWord(uint16_t address, register16_t value);

 		virtual uint8_t& reference() {
-			uint16_t effective = ADDRESS().word & m_addressMask;
+			auto effective = effectiveAddress(ADDRESS().word);
 			return m_locked[effective] ? placeDATA(m_bus[effective]) : referenceDATA(m_bus[effective]);
 		}

+		virtual uint16_t effectiveAddress(uint16_t address) const {
+			return address & m_addressMask;
+		}
+
 		void clear();
 		void loadRom(const std::string& path, uint16_t offset);
 		void loadRam(const std::string& path, uint16_t offset);