diff --git a/Processors/68000/Implementation/68000Implementation.hpp b/Processors/68000/Implementation/68000Implementation.hpp
index 24d597caa..5d9de8a77 100644
--- a/Processors/68000/Implementation/68000Implementation.hpp
+++ b/Processors/68000/Implementation/68000Implementation.hpp
@@ -779,8 +779,10 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 								case Operation::DIVU: {
 									// An attempt to divide by zero schedules an exception.
 									if(!active_program_->source->halves.low.full) {
-										// TODO: schedule an exception.
-										assert(false);
+										// Schedule a divide-by-zero exception.
+										active_program_ = nullptr;
+										active_micro_op_ = exception_micro_ops_;
+										populate_trap_steps(5, get_status());
 										break;
 									}
 
@@ -838,8 +840,10 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 								case Operation::DIVS: {
 									// An attempt to divide by zero schedules an exception.
 									if(!active_program_->source->halves.low.full) {
-										// TODO: schedule an exception.
-										assert(false);
+										// Schedule a divide-by-zero exception.
+										active_program_ = nullptr;
+										active_micro_op_ = exception_micro_ops_;
+										populate_trap_steps(5, get_status());
 										break;
 									}
 
@@ -1073,8 +1077,8 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 								case Operation::TRAP: {
 									// Select the trap steps as next; the initial microcycle should be 4 cycles long.
 									bus_program = trap_steps_;
-									bus_program->microcycle.length = HalfCycles(8);
 									populate_trap_steps((decoded_instruction_ & 15) + 32, get_status());
+									bus_program->microcycle.length = HalfCycles(8);
 
 									// The program counter to push is actually one slot ago.
 									program_counter_.full -= 2;
@@ -1084,8 +1088,8 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 									if(overflow_flag_) {
 										// Select the trap steps as next; the initial microcycle should be 4 cycles long.
 										bus_program = trap_steps_;
-										bus_program->microcycle.length = HalfCycles(0);
 										populate_trap_steps(7, get_status());
+										bus_program->microcycle.length = HalfCycles(0);
 										program_counter_.full -= 4;
 									}
 								} break;
@@ -1100,12 +1104,12 @@ template <class T, bool dtack_is_implicit, bool signal_will_perform> void Proces
 										negative_flag_ = is_under ? 1 : 0;
 
 										bus_program = trap_steps_;
+										populate_trap_steps(6, get_status());
 										if(is_under) {
 											bus_program->microcycle.length = HalfCycles(16);
 										} else {
 											bus_program->microcycle.length = HalfCycles(8);
 										}
-										populate_trap_steps(6, get_status());
 
 										// The program counter to push is two slots ago as whatever was the correct prefetch
 										// to continue without an exception has already happened, just in case.
diff --git a/Processors/68000/Implementation/68000Storage.cpp b/Processors/68000/Implementation/68000Storage.cpp
index 8b2dcaad3..8e88ce25b 100644
--- a/Processors/68000/Implementation/68000Storage.cpp
+++ b/Processors/68000/Implementation/68000Storage.cpp
@@ -10,6 +10,7 @@
 
 #include <algorithm>
 #include <sstream>
+#include <map>
 
 namespace CPU {
 namespace MC68000 {
@@ -364,9 +365,33 @@ struct ProcessorStorageConstructor {
 			return size_t(position - storage_.all_bus_steps_.begin());
 		}
 
+/*
+		// If the new steps already exist, just return the existing index to them;
+		// otherwise insert them. A lookup table of steps to start positions within
+		// all_bus_steps_ is maintained to shorten setup time here
+		auto potential_locations = locations_by_bus_step_[steps.front()];
+		for(auto index: potential_locations) {
+			if(index + steps.size() >= storage_.all_bus_steps_.size()) continue;
+
+			if(std::equal(
+					storage_.all_bus_steps_.begin() + ssize_t(index),
+					storage_.all_bus_steps_.begin() + ssize_t(index + steps.size()),
+					steps.begin())) {
+				return index;
+			}
+		}
+
+		// Copy to the end, and update potential_locations.
 		const auto start = storage_.all_bus_steps_.size();
 		std::copy(steps.begin(), steps.end(), std::back_inserter(storage_.all_bus_steps_));
+		auto index = start;
+		for(const auto &step: steps) {
+			locations_by_bus_step_[step].push_back(index);
+			++index;
+		}
+
 		return start;
+*/
 	}
 
 	/*!
@@ -3466,10 +3491,29 @@ struct ProcessorStorageConstructor {
 				}
 			}
 		}
+
+		printf("%lu total steps\n", storage_.all_bus_steps_.size());
 	}
 
 	private:
 		ProcessorStorage &storage_;
+
+/*		struct BusStepOrderer {
+			bool operator()( BusStep const& lhs, BusStep const& rhs ) const {
+				int action_diff = int(lhs.action) - int(rhs.action);
+				if(action_diff < 0) {
+					return true;
+				}
+				if(action_diff > 0) {
+					return false;
+				}
+
+				return
+					std::make_tuple(lhs.microcycle.value, lhs.microcycle.address, lhs.microcycle.length, lhs.microcycle.operation) <
+					std::make_tuple(rhs.microcycle.value, rhs.microcycle.address, rhs.microcycle.length, rhs.microcycle.operation);
+			}
+		};
+		std::map<BusStep, std::vector<size_t>, BusStepOrderer> locations_by_bus_step_;*/
 };
 
 }
@@ -3514,7 +3558,9 @@ CPU::MC68000::ProcessorStorage::ProcessorStorage()  {
 	all_micro_ops_.emplace_back();
 
 	// Install operations.
+	const std::clock_t start = std::clock();
 	constructor.install_instructions();
+	std::cout << "Construction took " << double(std::clock() - start) / double(CLOCKS_PER_SEC / 1000) << "ms" << std::endl;
 
 	// Realise the special programs as direct pointers.
 	reset_bus_steps_ = &all_bus_steps_[reset_offset];
diff --git a/Processors/68000/Implementation/68000Storage.hpp b/Processors/68000/Implementation/68000Storage.hpp
index 3e598be6a..acebfaf78 100644
--- a/Processors/68000/Implementation/68000Storage.hpp
+++ b/Processors/68000/Implementation/68000Storage.hpp
@@ -421,6 +421,9 @@ class ProcessorStorage {
 			precomputed_addresses_[1] = address_[7].full - 6;
 			precomputed_addresses_[2] = address_[7].full - 4;
 			address_[7].full -= 6;
+
+			// Set the default timing.
+			trap_steps_->microcycle.length = HalfCycles(8);
 		}