diff --git a/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme b/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme
index 610481df8..01069c685 100644
--- a/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme	
+++ b/OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme	
@@ -48,11 +48,6 @@
                BlueprintName = "Clock SignalTests"
                ReferencedContainer = "container:Clock Signal.xcodeproj">
             </BuildableReference>
-            <SkippedTests>
-               <Test
-                  Identifier = "ZexallTests">
-               </Test>
-            </SkippedTests>
          </TestableReference>
          <TestableReference
             skipped = "YES">
diff --git a/Processors/65816/Implementation/65816Implementation.hpp b/Processors/65816/Implementation/65816Implementation.hpp
index 157563a20..5e888c359 100644
--- a/Processors/65816/Implementation/65816Implementation.hpp
+++ b/Processors/65816/Implementation/65816Implementation.hpp
@@ -50,8 +50,10 @@ template <typename BusHandler, bool uses_ready_line> void Processor<BusHandler,
 					// The exception program will determine the appropriate way to respond
 					// based on the pending exception if one exists; otherwise just do a
 					// standard fetch-decode-execute.
-					const auto offset = instructions[selected_exceptions_ ? size_t(OperationSlot::Exception) : size_t(OperationSlot::FetchDecodeExecute)].program_offsets[0];
-					next_op_ = &micro_ops_[offset];
+					const size_t slot = size_t(selected_exceptions_ ? OperationSlot::Exception : OperationSlot::FetchDecodeExecute);
+					active_instruction_ = &instructions[slot];
+
+					next_op_ = &micro_ops_[active_instruction_->program_offsets[0]];
 					instruction_buffer_.clear();
 					data_buffer_.clear();
 					last_operation_pc_ = registers_.pc;
@@ -954,6 +956,7 @@ void ProcessorBase::set_power_on(bool active) {
 		pending_exceptions_ |= PowerOn;
 	} else {
 		pending_exceptions_ &= ~PowerOn;
+		selected_exceptions_ &= ~PowerOn;
 	}
 }
 
diff --git a/Processors/65816/Implementation/65816Storage.cpp b/Processors/65816/Implementation/65816Storage.cpp
index 4aa494b50..f254806f9 100644
--- a/Processors/65816/Implementation/65816Storage.cpp
+++ b/Processors/65816/Implementation/65816Storage.cpp
@@ -43,7 +43,8 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
 
 	typedef void (* Generator)(AccessType, bool, const std::function<void(MicroOp)>&);
 	using GeneratorKey = std::tuple<AccessType, Generator>;
-	std::map<GeneratorKey, std::pair<size_t, size_t>> installed_patterns;
+	using PatternTable = std::map<GeneratorKey, std::pair<size_t, size_t>>;
+	PatternTable installed_patterns;
 
 	int opcode = 0;
 	enum class AccessMode {
@@ -51,55 +52,15 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
 		Always8Bit,
 		Always16Bit
 	};
+
 	void install(Generator generator, Operation operation, AccessMode access_mode = AccessMode::Mixed) {
 		// Determine the access type implied by this operation.
 		const AccessType access_type = access_type_for_operation(operation);
 
-		// Check whether this access type + addressing mode generator has already been generated.
-		const auto key = std::make_pair(access_type, generator);
-		const auto map_entry = installed_patterns.find(key);
-		size_t micro_op_location_8, micro_op_location_16;
-
-		// If it wasn't found, generate it now in both 8- and 16-bit variants.
-		// Otherwise, get the location of the existing entries.
-		if(map_entry == installed_patterns.end()) {
-			// Generate 8-bit steps.
-			micro_op_location_8 = storage_.micro_ops_.size();
-			(*generator)(access_type, true, [this] (MicroOp op) {
-				this->storage_.micro_ops_.push_back(op);
-			});
-			storage_.micro_ops_.push_back(OperationMoveToNextProgram);
-
-			// Generate 16-bit steps.
-			micro_op_location_16 = storage_.micro_ops_.size();
-			(*generator)(access_type, false, [this] (MicroOp op) {
-				this->storage_.micro_ops_.push_back(op);
-			});
-			storage_.micro_ops_.push_back(OperationMoveToNextProgram);
-
-			// Minor optimisation: elide the steps if 8- and 16-bit steps are equal.
-			bool are_equal = true;
-			size_t c = 0;
-			while(true) {
-				if(storage_.micro_ops_[micro_op_location_8 + c] != storage_.micro_ops_[micro_op_location_16 + c]) {
-					are_equal = false;
-					break;
-				}
-				if(storage_.micro_ops_[micro_op_location_8 + c] == OperationMoveToNextProgram) break;
-				++c;
-			}
-
-			if(are_equal) {
-				storage_.micro_ops_.resize(micro_op_location_16);
-				micro_op_location_16 = micro_op_location_8;
-			}
-
-			// Insert into the map.
-			installed_patterns[key] = std::make_pair(micro_op_location_8, micro_op_location_16);
-		} else {
-			micro_op_location_8 = map_entry->second.first;
-			micro_op_location_16 = map_entry->second.second;
-		}
+		// Install the bus pattern.
+		const auto map_entry = install(generator, access_type);
+		const size_t micro_op_location_8 = map_entry->second.first;
+		const size_t micro_op_location_16 = map_entry->second.second;
 
 		// Fill in the proper table entries and increment the opcode pointer.
 		storage_.instructions[opcode].program_offsets[0] = (access_mode == AccessMode::Always8Bit) ? uint16_t(micro_op_location_8) : uint16_t(micro_op_location_16);
@@ -110,8 +71,7 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
 	}
 
 	void set_exception_generator(Generator generator) {
-		const auto key = std::make_pair(AccessType::Read, generator);
-		const auto map_entry = installed_patterns.find(key);
+		const auto map_entry = install(generator);
 		storage_.instructions[size_t(ProcessorStorage::OperationSlot::Exception)].program_offsets[0] =
 		storage_.instructions[size_t(ProcessorStorage::OperationSlot::Exception)].program_offsets[1] = uint16_t(map_entry->second.first);
 		storage_.instructions[size_t(ProcessorStorage::OperationSlot::Exception)].operation = JMPind;
@@ -124,6 +84,57 @@ struct CPU::WDC65816::ProcessorStorageConstructor {
 		storage_.micro_ops_.push_back(OperationDecode);
 	}
 
+	private:
+
+	PatternTable::iterator install(Generator generator, AccessType access_type = AccessType::Read) {
+		// Check whether this access type + addressing mode generator has already been generated.
+		const auto key = std::make_pair(access_type, generator);
+		const auto map_entry = installed_patterns.find(key);
+
+		// If it wasn't found, generate it now in both 8- and 16-bit variants.
+		// Otherwise, get the location of the existing entries.
+		if(map_entry != installed_patterns.end()) {
+			return map_entry;
+		}
+
+		// Generate 8-bit steps.
+		const size_t micro_op_location_8 = storage_.micro_ops_.size();
+		(*generator)(access_type, true, [this] (MicroOp op) {
+			this->storage_.micro_ops_.push_back(op);
+		});
+		storage_.micro_ops_.push_back(OperationMoveToNextProgram);
+
+		// Generate 16-bit steps.
+		size_t micro_op_location_16 = storage_.micro_ops_.size();
+		(*generator)(access_type, false, [this] (MicroOp op) {
+			this->storage_.micro_ops_.push_back(op);
+		});
+		storage_.micro_ops_.push_back(OperationMoveToNextProgram);
+
+		// Minor optimisation: elide the steps if 8- and 16-bit steps are equal.
+		bool are_equal = true;
+		size_t c = 0;
+		while(true) {
+			if(storage_.micro_ops_[micro_op_location_8 + c] != storage_.micro_ops_[micro_op_location_16 + c]) {
+				are_equal = false;
+				break;
+			}
+			if(storage_.micro_ops_[micro_op_location_8 + c] == OperationMoveToNextProgram) break;
+			++c;
+		}
+
+		if(are_equal) {
+			storage_.micro_ops_.resize(micro_op_location_16);
+			micro_op_location_16 = micro_op_location_8;
+		}
+
+		// Insert into the map.
+		auto [iterator, _] = installed_patterns.insert(std::make_pair(key, std::make_pair(micro_op_location_8, micro_op_location_16)));
+		return iterator;
+	}
+
+	public:
+
 	/*
 		Code below is structured to ease translation from Table 5-7 of the 2018
 		edition of the WDC 65816 datasheet.
diff --git a/Processors/65816/Implementation/65816Storage.hpp b/Processors/65816/Implementation/65816Storage.hpp
index 4edf9cf76..3dc0c55a4 100644
--- a/Processors/65816/Implementation/65816Storage.hpp
+++ b/Processors/65816/Implementation/65816Storage.hpp
@@ -292,8 +292,10 @@ struct ProcessorStorage {
 	static constexpr int IRQ = Flag::Interrupt;	// This makes masking a lot easier later on; this is 1 << 2.
 	static constexpr int NMI = 1 << 3;
 	static constexpr int Abort = 1 << 4;
-	int pending_exceptions_ = PowerOn;	// By default.
-	int selected_exceptions_ = 0;
+
+	static constexpr int default_exceptions = PowerOn;
+	int pending_exceptions_ = default_exceptions;
+	int selected_exceptions_ = default_exceptions;
 
 	bool ready_line_ = false;
 	bool memory_lock_ = false;