diff --git a/LR35902/src/IoRegisters.cpp b/LR35902/src/IoRegisters.cpp
index c63e8fd..83d3106 100644
--- a/LR35902/src/IoRegisters.cpp
+++ b/LR35902/src/IoRegisters.cpp
@@ -40,7 +40,7 @@ void EightBit::GameBoy::IoRegisters::Bus_ReadingByte(EightBit::EventArgs) {
 				auto upOrSelect = (live && !m_p12) ? 0 : Chip::Bit2;
 				auto downOrStart = (live && !m_p13) ? 0 : Chip::Bit3;
 				auto lowNibble = rightOrA | leftOrB | upOrSelect | downOrStart;
-				auto highNibble = Chip::promoteNibble(Chip::Mask4);
+				constexpr auto highNibble = Chip::promoteNibble(Chip::Mask4);
 				auto value = lowNibble | highNibble;
 				poke(port, lowNibble | highNibble);
 			}
diff --git a/inc/BigEndianProcessor.h b/inc/BigEndianProcessor.h
index 871a15c..05abf39 100644
--- a/inc/BigEndianProcessor.h
+++ b/inc/BigEndianProcessor.h
@@ -1,13 +1,14 @@
 #pragma once
 
-#include "Bus.h"
-#include "Register.h"
 #include "Processor.h"
 
 namespace EightBit {
+
+	class Bus;
+
 	class BigEndianProcessor : public Processor {
 	public:
-		~BigEndianProcessor() {};
+		~BigEndianProcessor() = default;
 
 		register16_t peekWord(register16_t address) final;
 		void pokeWord(register16_t address, register16_t value) final;
diff --git a/inc/InputOutput.h b/inc/InputOutput.h
index eb2954f..f238278 100644
--- a/inc/InputOutput.h
+++ b/inc/InputOutput.h
@@ -3,7 +3,6 @@
 #include <cstdint>
 #include <array>
 
-#include "Signal.h"
 #include "Memory.h"
 #include "Ram.h"
 
@@ -14,7 +13,7 @@ namespace EightBit {
 
 		InputOutput() = default;
 
-		[[nodiscard]] size_t size() const override;
+		[[nodiscard]] size_t size() const noexcept override;
 		[[nodiscard]] uint8_t peek(uint16_t address) const override;
 
 		[[nodiscard]] uint8_t& reference(uint16_t address) override;
diff --git a/inc/IntelProcessor.h b/inc/IntelProcessor.h
index f25d243..4a71974 100644
--- a/inc/IntelProcessor.h
+++ b/inc/IntelProcessor.h
@@ -3,7 +3,6 @@
 #include <cstdint>
 #include <array>
 
-#include "Bus.h"
 #include "LittleEndianProcessor.h"
 #include "Register.h"
 #include "EventArgs.h"
@@ -11,6 +10,9 @@
 #include "EightBitCompilerDefinitions.h"
 
 namespace EightBit {
+
+	class Bus;
+
 	class IntelProcessor : public LittleEndianProcessor {
 	public:
 		struct opcode_decoded_t {
diff --git a/inc/LittleEndianProcessor.h b/inc/LittleEndianProcessor.h
index edbb46f..73d432f 100644
--- a/inc/LittleEndianProcessor.h
+++ b/inc/LittleEndianProcessor.h
@@ -1,10 +1,11 @@
 #pragma once
 
-#include "Bus.h"
-#include "Register.h"
 #include "Processor.h"
 
 namespace EightBit {
+
+	class Bus;
+
 	class LittleEndianProcessor : public Processor {
 	public:
 		~LittleEndianProcessor() = default;
diff --git a/inc/Processor.h b/inc/Processor.h
index 7d2aa02..5026c52 100644
--- a/inc/Processor.h
+++ b/inc/Processor.h
@@ -5,8 +5,6 @@
 #include "ClockedChip.h"
 #include "Bus.h"
 #include "Register.h"
-#include "EventArgs.h"
-#include "Signal.h"
 
 #include "EightBitCompilerDefinitions.h"
 
@@ -15,9 +13,9 @@ namespace EightBit {
 	public:
 		// b: number of bits representing the number in x
 		// x: sign extend this b-bit number to r
-		[[nodiscard]] static int8_t signExtend(int b, uint8_t x);
+		[[nodiscard]] static int8_t signExtend(int b, uint8_t x) noexcept;
 
-		~Processor() {};
+		~Processor() = default;
 
 		[[nodiscard]] auto& PC() noexcept { return m_pc; }
 
diff --git a/inc/Ram.h b/inc/Ram.h
index d407f8c..18e0830 100644
--- a/inc/Ram.h
+++ b/inc/Ram.h
@@ -1,7 +1,5 @@
 #pragma once
 
-#include <cstdint>
-
 #include "Rom.h"
 
 namespace EightBit {
diff --git a/inc/UnusedMemory.h b/inc/UnusedMemory.h
index 0085126..c6f2bd7 100644
--- a/inc/UnusedMemory.h
+++ b/inc/UnusedMemory.h
@@ -14,7 +14,7 @@ namespace EightBit {
 	class UnusedMemory final : public Memory {
 	public:
 		UnusedMemory(size_t size, uint8_t value);
-		~UnusedMemory() {};
+		~UnusedMemory() = default;
 
 		[[nodiscard]] size_t size() const final;
 		[[nodiscard]] uint8_t peek(uint16_t address) const final;
diff --git a/src/InputOutput.cpp b/src/InputOutput.cpp
index 6ea37ef..75f71fc 100644
--- a/src/InputOutput.cpp
+++ b/src/InputOutput.cpp
@@ -5,7 +5,7 @@
 
 #include "Register.h"
 
-size_t EightBit::InputOutput::size() const {
+size_t EightBit::InputOutput::size() const noexcept {
 	return 0x100;
 }
 
diff --git a/src/IntelProcessor.cpp b/src/IntelProcessor.cpp
index 90f7af9..5a65976 100644
--- a/src/IntelProcessor.cpp
+++ b/src/IntelProcessor.cpp
@@ -4,7 +4,7 @@
 EightBit::IntelProcessor::IntelProcessor(Bus& bus)
 : LittleEndianProcessor(bus) {
 	for (int i = 0; i < 0x100; ++i)
-		m_decodedOpcodes[i] = i;
+		m_decodedOpcodes.at(i) = i;
 
 	LoweredHALT.connect([this](EventArgs) { --PC(); });
 	RaisedHALT.connect([this](EventArgs) { ++PC(); });
diff --git a/src/Processor.cpp b/src/Processor.cpp
index fcce6e9..cbfcd58 100644
--- a/src/Processor.cpp
+++ b/src/Processor.cpp
@@ -60,7 +60,7 @@ int EightBit::Processor::execute(const uint8_t value) {
 }
 
 // http://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend
-int8_t EightBit::Processor::signExtend(const int b, uint8_t x) {
+int8_t EightBit::Processor::signExtend(const int b, uint8_t x) noexcept {
 	const uint8_t m = bit(b - 1); // mask can be pre-computed if b is fixed
 	x = x & (bit(b) - 1);  // (Skip this if bits in x above position b are already zero.)
 	const auto result = (x ^ m) - m;