Remove some "tricksy" code from the Z80 emulator chain.

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

src/Bus.cpp

@@ -11,7 +11,7 @@ uint8_t& EightBit::Bus::DATA() {
 	return *m_data;
 }
 
-uint8_t& EightBit::Bus::placeDATA(uint8_t value) {
+uint8_t& EightBit::Bus::placeDATA(const uint8_t value) {
 	m_temporary = value;
 	m_data = &m_temporary;
 	return DATA();
@@ -22,17 +22,17 @@ uint8_t& EightBit::Bus::referenceDATA(uint8_t& value) {
 	return DATA();
 }
 
-uint8_t EightBit::Bus::peek(uint16_t address) {
+uint8_t EightBit::Bus::peek(const uint16_t address) {
 	bool rom;
 	return reference(address, rom);
 }
 
-void EightBit::Bus::poke(uint16_t address, uint8_t value) {
+void EightBit::Bus::poke(const uint16_t address, const uint8_t value) {
 	bool rom;
 	reference(address, rom) = value;
 }
 
-uint16_t EightBit::Bus::peekWord(uint16_t address) {
+uint16_t EightBit::Bus::peekWord(const uint16_t address) {
 	register16_t returned;
 	returned.low = peek(address);
 	returned.high = peek(address + 1);
@@ -46,28 +46,28 @@ uint8_t EightBit::Bus::read() {
 	return returned;
 }
 
-uint8_t EightBit::Bus::read(uint16_t offset) {
+uint8_t EightBit::Bus::read(const uint16_t offset) {
 	ADDRESS().word = offset;
 	return read();
 }
 
-uint8_t EightBit::Bus::read(register16_t address) {
+uint8_t EightBit::Bus::read(const register16_t address) {
 	ADDRESS() = address;
 	return read();
 }
 
-void EightBit::Bus::write(uint8_t value) {
+void EightBit::Bus::write(const uint8_t value) {
 	WritingByte.fire(ADDRESS().word);
 	reference() = value;
 	WrittenByte.fire(ADDRESS().word);
 }
 
-void EightBit::Bus::write(uint16_t offset, uint8_t value) {
+void EightBit::Bus::write(const uint16_t offset, const uint8_t value) {
 	ADDRESS().word = offset;
 	write(value);
 }
 
-void EightBit::Bus::write(register16_t address, uint8_t value) {
+void EightBit::Bus::write(const register16_t address, const uint8_t value) {
 	ADDRESS() = address;
 	write(value);
 }
@@ -75,5 +75,5 @@ void EightBit::Bus::write(register16_t address, uint8_t value) {
 uint8_t& EightBit::Bus::reference() {
 	bool rom;
 	auto& value = reference(ADDRESS().word, rom);
-	return LIKELY(!rom) ? referenceDATA(value) : placeDATA(value);
+	return rom ? placeDATA(value) : referenceDATA(value);
 }

src/InputOutput.cpp

@@ -1,31 +1,31 @@
 #include "stdafx.h"
 #include "InputOutput.h"
 
-uint8_t EightBit::InputOutput::readInputPort(uint8_t port) {
+uint8_t EightBit::InputOutput::readInputPort(const uint8_t port) {
 	OnReadingPort(port);
 	const auto value = m_input[port];
 	OnReadPort(port);
 	return value;
 }
 
-void EightBit::InputOutput::writeOutputPort(uint8_t port, uint8_t value) {
+void EightBit::InputOutput::writeOutputPort(const uint8_t port, const uint8_t value) {
 	OnWritingPort(port);
 	m_output[port] = value;
 	OnWrittenPort(port);
 }
 
-void EightBit::InputOutput::OnReadingPort(uint8_t port) {
+void EightBit::InputOutput::OnReadingPort(const uint8_t port) {
 	ReadingPort.fire(port);
 }
 
-void EightBit::InputOutput::OnReadPort(uint8_t port) {
+void EightBit::InputOutput::OnReadPort(const uint8_t port) {
 	ReadPort.fire(port);
 }
 
-void EightBit::InputOutput::OnWritingPort(uint8_t port) {
+void EightBit::InputOutput::OnWritingPort(const uint8_t port) {
 	WritingPort.fire(port);
 }
 
-void EightBit::InputOutput::OnWrittenPort(uint8_t port) {
+void EightBit::InputOutput::OnWrittenPort(const uint8_t port) {
 	WrittenPort.fire(port);
 }

src/IntelProcessor.cpp

@@ -12,7 +12,7 @@ void EightBit::IntelProcessor::reset() {
 	SP().word = AF().word = BC().word = DE().word = HL().word = Mask16;
 }
 
-void EightBit::IntelProcessor::push(uint8_t value) {
+void EightBit::IntelProcessor::push(const uint8_t value) {
 	BUS().write(--SP().word, value);
 }
 
@@ -27,7 +27,7 @@ EightBit::register16_t EightBit::IntelProcessor::getWord() {
 	return returned;
 }
 
-void EightBit::IntelProcessor::setWord(register16_t value) {
+void EightBit::IntelProcessor::setWord(const register16_t value) {
 	BUS().write(MEMPTR().word++, value.low);
 	BUS().write(++BUS().ADDRESS().word, value.high);
 }

src/Processor.cpp

@@ -14,7 +14,7 @@ void EightBit::Processor::reset() {
 	PC().word = 0;
 }
 
-int EightBit::Processor::run(int limit) {
+int EightBit::Processor::run(const int limit) {
 	int current = 0;
 	while (LIKELY(powered()) && current < limit) {
 		current += singleStep();