diff --git a/InstructionSets/x86/Implementation/LoadStore.hpp b/InstructionSets/x86/Implementation/LoadStore.hpp
index 4e8132856..398d5fa6e 100644
--- a/InstructionSets/x86/Implementation/LoadStore.hpp
+++ b/InstructionSets/x86/Implementation/LoadStore.hpp
@@ -96,8 +96,6 @@ void lmsw(
 	context.registers.set_msw(source);
 	if(source & MachineStatus::ProtectedModeEnable) {
 		context.cpu_control.set_mode(Mode::Protected286);
-//		context.memory.set_mode(Mode::Protected286);
-//		context.segments.set_mode(Mode::Protected286);
 	}
 }
 
diff --git a/InstructionSets/x86/Model.hpp b/InstructionSets/x86/Model.hpp
index c1b67e69a..faec3c524 100644
--- a/InstructionSets/x86/Model.hpp
+++ b/InstructionSets/x86/Model.hpp
@@ -47,8 +47,16 @@ static constexpr bool has_mode(const Model model, const Mode mode) {
 	}
 	return false;
 }
+
 static constexpr bool uses_8086_exceptions(const Model model) {
 	return model <= Model::i80186;
 }
 
+
+template <Model model>
+concept has_descriptor_tables = model >= Model::i80286;
+
+template <Model model>
+concept has_32bit_instructions = model >= Model::i80386;
+
 }
diff --git a/InstructionSets/x86/Perform.hpp b/InstructionSets/x86/Perform.hpp
index 684b46995..c14f8bc21 100644
--- a/InstructionSets/x86/Perform.hpp
+++ b/InstructionSets/x86/Perform.hpp
@@ -16,12 +16,33 @@
 
 namespace InstructionSet::x86 {
 
+//
+// Register interface requirements.
+//
 template <typename RegistersT, Model model>
 concept is_registers = true;
 
+//
+// Segment/descriptor interface requirements.
+//
 template <typename SegmentsT, Model model>
-concept is_segments = true;
+concept has_segment_update = requires(SegmentsT segments) {
+	segments.did_update(Source{});
+};
 
+template <typename SegmentsT, Model model>
+concept has_descriptor_table_update = requires(SegmentsT segments) {
+	segments.did_update(DescriptorTable{});
+};
+
+template <typename SegmentsT, Model model>
+concept is_segments =
+	has_segment_update<SegmentsT, model> &&
+	(!has_descriptor_tables<model> || has_descriptor_table_update<SegmentsT, model>);
+
+//
+//
+//
 template <typename LinearMemoryT, Model model>
 concept is_linear_memory = true;
 
@@ -29,10 +50,19 @@ template <typename SegmentedMemoryT, Model model>
 concept is_segmented_memory = true;
 
 template <typename FlowControllerT, Model model>
-concept is_flow_controller = true;
+concept is_flow_controller = requires(FlowControllerT controller) {
+	controller.template jump<uint16_t>(uint16_t{});
+	controller.template jump<uint16_t>(uint16_t{}, uint16_t{});
+	controller.halt();
+	controller.wait();
+	controller.repeat_last();
+
+	// TODO: if 32-bit, check for jump<uint32_t>, Somehow?
+};
 
 template <typename CPUControlT, Model model>
 concept is_cpu_control = true;
+// TODO: if 286 or better, cpu_control.set_mode(Mode{});
 
 template <typename ContextT>
 concept is_context = requires(ContextT context) {