diff --git a/InstructionSets/x86/Implementation/PerformImplementation.hpp b/InstructionSets/x86/Implementation/PerformImplementation.hpp
index 4ef6cad44..8a1e7a6f7 100644
--- a/InstructionSets/x86/Implementation/PerformImplementation.hpp
+++ b/InstructionSets/x86/Implementation/PerformImplementation.hpp
@@ -524,7 +524,7 @@ template <
 	const uint16_t ip = context.memory.template access<uint16_t, AccessType::PreauthorisedRead>(address);
 	const uint16_t cs = context.memory.template access<uint16_t, AccessType::PreauthorisedRead>(address + 2);
 
-	auto flags = context.flags.get();
+	const auto flags = context.flags.get();
 	Primitive::push<uint16_t, true>(flags, context);
 	context.flags.template set_from<Flag::Interrupt, Flag::Trap>(0);
 
diff --git a/InstructionSets/x86/Implementation/Stack.hpp b/InstructionSets/x86/Implementation/Stack.hpp
index 6568d2040..5f538dcd0 100644
--- a/InstructionSets/x86/Implementation/Stack.hpp
+++ b/InstructionSets/x86/Implementation/Stack.hpp
@@ -18,7 +18,7 @@ namespace InstructionSet::x86::Primitive {
 // which should place the value of SP after the push onto the stack.
 template <typename IntT, bool preauthorised, typename ContextT>
 void push(
-	IntT &value,
+	const IntT &value,
 	ContextT &context
 ) {
 	context.registers.sp() -= sizeof(IntT);
@@ -45,7 +45,7 @@ IntT pop(
 
 template <typename ContextT>
 void sahf(
-	uint8_t &ah,
+	const uint8_t &ah,
 	ContextT &context
 ) {
 	/*
@@ -86,7 +86,7 @@ template <typename ContextT>
 void pushf(
 	ContextT &context
 ) {
-	uint16_t value = context.flags.get();
+	const uint16_t value = context.flags.get();
 	push<uint16_t, false>(value, context);
 }
 
@@ -121,7 +121,7 @@ void pusha(
 	ContextT &context
 ) {
 	context.memory.preauthorise_stack_read(sizeof(IntT) * 8);
-	IntT initial_sp = context.registers.sp();
+	const IntT initial_sp = context.registers.sp();
 	if constexpr (std::is_same_v<IntT, uint32_t>) {
 		push<uint32_t, true>(context.registers.eax(), context);
 		push<uint32_t, true>(context.registers.ecx(), context);
diff --git a/InstructionSets/x86/Perform.hpp b/InstructionSets/x86/Perform.hpp
index 46821aab7..62110f543 100644
--- a/InstructionSets/x86/Perform.hpp
+++ b/InstructionSets/x86/Perform.hpp
@@ -41,6 +41,7 @@ template <
 	ContextT &context
 );
 
+/// Performs an x86 INT operation; also often used by other operations to indicate an error.
 template <
 	typename ContextT
 > void interrupt(
diff --git a/Machines/PCCompatible/Memory.hpp b/Machines/PCCompatible/Memory.hpp
index ce2c5524f..ccb988f4b 100644
--- a/Machines/PCCompatible/Memory.hpp
+++ b/Machines/PCCompatible/Memory.hpp
@@ -111,12 +111,12 @@ struct Memory {
 		//
 		// Helper for instruction fetch.
 		//
-		std::pair<const uint8_t *, size_t> next_code() {
+		std::pair<const uint8_t *, size_t> next_code() const {
 			const uint32_t start = segments_.cs_base_ + registers_.ip();
 			return std::make_pair(&memory[start], 0x10'000 - start);
 		}
 
-		std::pair<const uint8_t *, size_t> all() {
+		std::pair<const uint8_t *, size_t> all() const {
 			return std::make_pair(memory.data(), 0x10'000);
 		}
 
@@ -136,7 +136,7 @@ struct Memory {
 		Registers &registers_;
 		const Segments &segments_;
 
-		uint32_t segment_base(InstructionSet::x86::Source segment) {
+		uint32_t segment_base(const InstructionSet::x86::Source segment) const {
 			using Source = InstructionSet::x86::Source;
 			switch(segment) {
 				default:			return segments_.ds_base_;
@@ -146,13 +146,13 @@ struct Memory {
 			}
 		}
 
-		uint32_t address(InstructionSet::x86::Source segment, uint16_t offset) {
+		uint32_t address(const InstructionSet::x86::Source segment, const uint16_t offset) const {
 			return (segment_base(segment) + offset) & 0xf'ffff;
 		}
 
 		template <AccessType type>
 		typename InstructionSet::x86::Accessor<uint16_t, type>::type
-		split_word(uint32_t low_address, uint32_t high_address) {
+		split_word(const uint32_t low_address, const uint32_t high_address) {
 			if constexpr (is_writeable(type)) {
 				write_back_address_[0] = low_address;
 				write_back_address_[1] = high_address;