Merge pull request #971 from TomHarte/ChaseHQ

Flip meaning of INT1 input read.

Analyser/Static/Enterprise/StaticAnalyser.cpp

@@ -67,7 +67,7 @@ Analyser::Static::TargetList Analyser::Static::Enterprise::GetTargets(const Medi
 
 			if(!has_exdos_ini) {
 				if(did_pick_file) {
-					target->loading_command = std::string("run \"") + selected_file->name + "." + selected_file->extension + "\"";
+					target->loading_command = std::string("run \"") + selected_file->name + "." + selected_file->extension + "\"\n";
 				} else {
 					target->loading_command = ":dir\n";
 				}

Analyser/Static/Enterprise/Target.hpp

@@ -24,11 +24,13 @@ struct Target: public Analyser::Static::Target, public Reflection::StructImpl<Ta
 	ReflectableEnum(EXOSVersion, v10, v20, v21, v23, Any);
 	ReflectableEnum(BASICVersion, v10, v11, v21, Any, None);
 	ReflectableEnum(DOS, EXDOS, None);
+	ReflectableEnum(Speed, FourMHz, SixMHz);
 
 	Model model = Model::Enterprise128;
 	EXOSVersion exos_version = EXOSVersion::Any;
 	BASICVersion basic_version = BASICVersion::None;
 	DOS dos = DOS::None;
+	Speed speed = Speed::FourMHz;
 	std::string loading_command;
 
 	Target() : Analyser::Static::Target(Machine::Enterprise) {
@@ -37,11 +39,13 @@ struct Target: public Analyser::Static::Target, public Reflection::StructImpl<Ta
 			AnnounceEnum(EXOSVersion);
 			AnnounceEnum(BASICVersion);
 			AnnounceEnum(DOS);
+			AnnounceEnum(Speed);
 
 			DeclareField(model);
 			DeclareField(exos_version);
 			DeclareField(basic_version);
 			DeclareField(dos);
+			DeclareField(speed);
 		}
 	}
 };

Machines/Enterprise/Dave.cpp

@@ -16,7 +16,7 @@ Audio::Audio(Concurrency::DeferringAsyncTaskQueue &audio_queue) :
 	audio_queue_(audio_queue) {}
 
 void Audio::write(uint16_t address, uint8_t value) {
-	address &= 0xf;
+	address &= 0x1f;
 	audio_queue_.defer([address, value, this] {
 		switch(address) {
 			case 0:	case 2:	case 4:
@@ -54,6 +54,10 @@ void Audio::write(uint16_t address, uint8_t value) {
 			break;
 			case 11:	noise_.amplitude[0] = value & 0x3f;		break;
 			case 15:	noise_.amplitude[1] = value & 0x3f;		break;
+
+			case 31:
+				global_divider_reload_ = 2 + ((value >> 1)&1);
+			break;
 		}
 	});
 }
@@ -65,37 +69,74 @@ void Audio::set_sample_volume_range(int16_t range) {
 }
 
 void Audio::update_channel(int c) {
-	if(channels_[c].sync) {
-		channels_[c].count = channels_[c].reload;
-		channels_[c].output <<= 1;
-		return;
-	}
-
 	auto output = channels_[c].output & 1;
 	channels_[c].output <<= 1;
-	if(!channels_[c].count) {
+	if(channels_[c].sync) {
 		channels_[c].count = channels_[c].reload;
+		output = 0;
+	} else {
+		if(!channels_[c].count) {
+			channels_[c].count = channels_[c].reload;
 
-		if(channels_[c].distortion == Channel::Distortion::None)
-			output ^= 1;
-		else
-			output = poly_state_[int(channels_[c].distortion)];
+			if(channels_[c].distortion == Channel::Distortion::None)
+				output ^= 1;
+			else
+				output = poly_state_[int(channels_[c].distortion)];
+		} else {
+			--channels_[c].count;
+		}
 
 		if(channels_[c].high_pass && (channels_[(c+1)%3].output&3) == 2) {
 			output = 0;
 		}
-		if(channels_[c].ring_modulate) {
-			output = ~(output ^ channels_[(c+2)%3].output) & 1;
-		}
-	} else {
-		--channels_[c].count;
+	}
+
+	// Ring modulation applies even when sync is enabled, per SIDBasic.
+	if(channels_[c].ring_modulate) {
+		output = ~(output ^ channels_[(c+2)%3].output) & 1;
 	}
 
 	channels_[c].output |= output;
 }
 
 void Audio::get_samples(std::size_t number_of_samples, int16_t *target) {
-	for(size_t c = 0; c < number_of_samples; c++) {
+	int16_t output_level[2];
+	size_t c = 0;
+	while(c < number_of_samples) {
+		// I'm unclear on the details of the time division multiplexing so,
+		// for now, just sum the outputs.
+		output_level[0] =
+			volume_ *
+				(use_direct_output_[0] ?
+					channels_[0].amplitude[0]
+					: (
+						channels_[0].amplitude[0] * (channels_[0].output & 1) +
+						channels_[1].amplitude[0] * (channels_[1].output & 1) +
+						channels_[2].amplitude[0] * (channels_[2].output & 1) +
+						noise_.amplitude[0] * noise_.final_output
+				));
+
+		output_level[1] =
+			volume_ *
+				(use_direct_output_[1] ?
+					channels_[0].amplitude[1]
+					: (
+						channels_[0].amplitude[1] * (channels_[0].output & 1) +
+						channels_[1].amplitude[1] * (channels_[1].output & 1) +
+						channels_[2].amplitude[1] * (channels_[2].output & 1) +
+						noise_.amplitude[1] * noise_.final_output
+				));
+
+		while(global_divider_ && c < number_of_samples) {
+			--global_divider_;
+			*reinterpret_cast<uint32_t *>(&target[c << 1]) = *reinterpret_cast<uint32_t *>(output_level);
+			++c;
+		}
+
+		global_divider_ = global_divider_reload_;
+		if(!global_divider_) {
+			global_divider_ = global_divider_reload_;
+		}
 		poly_state_[int(Channel::Distortion::FourBit)] = poly4_.next();
 		poly_state_[int(Channel::Distortion::FiveBit)] = poly5_.next();
 		poly_state_[int(Channel::Distortion::SevenBit)] = poly7_.next();
@@ -162,30 +203,6 @@ void Audio::get_samples(std::size_t number_of_samples, int16_t *target) {
 		} else {
 			noise_.final_output = noise_.output & 1;
 		}
-
-		// I'm unclear on the details of the time division multiplexing so,
-		// for now, just sum the outputs.
-		target[(c << 1) + 0] =
-			volume_ *
-				(use_direct_output_[0] ?
-					channels_[0].amplitude[0]
-					: (
-						channels_[0].amplitude[0] * (channels_[0].output & 1) +
-						channels_[1].amplitude[0] * (channels_[1].output & 1) +
-						channels_[2].amplitude[0] * (channels_[2].output & 1) +
-						noise_.amplitude[0] * noise_.final_output
-				));
-
-		target[(c << 1) + 1] =
-			volume_ *
-				(use_direct_output_[1] ?
-					channels_[0].amplitude[1]
-					: (
-						channels_[0].amplitude[1] * (channels_[0].output & 1) +
-						channels_[1].amplitude[1] * (channels_[1].output & 1) +
-						channels_[2].amplitude[1] * (channels_[2].output & 1) +
-						noise_.amplitude[1] * noise_.final_output
-				));
 	}
 }
 
@@ -198,7 +215,7 @@ uint8_t TimedInterruptSource::get_new_interrupts() {
 }
 
 void TimedInterruptSource::write(uint16_t address, uint8_t value) {
-	address &= 15;
+	address &= 0x1f;
 	switch(address) {
 		default: break;
 
@@ -209,21 +226,15 @@ void TimedInterruptSource::write(uint16_t address, uint8_t value) {
 			channels_[address >> 1].reload = uint16_t((channels_[address >> 1].reload & 0x00ff) | ((value & 0xf) << 8));
 		break;
 
-		case 7: {
+		case 7:
 			channels_[0].sync = value & 0x01;
 			channels_[1].sync = value & 0x02;
+			rate_ = InterruptRate((value >> 5) & 3);
+		break;
 
-			const InterruptRate rate = InterruptRate((value >> 5) & 3);
-			if(rate != rate_) {
-				rate_ = rate;
-
-				if(rate_ >= InterruptRate::ToneGenerator0) {
-					programmable_level_ = channels_[int(rate_) - int(InterruptRate::ToneGenerator0)].level;
-				} else {
-					programmable_offset_ = programmble_reload(rate_);
-				}
-			}
-		} break;
+		case 31:
+			global_divider_ = Cycles(2 + ((value >> 1)&1));
+		break;
 	}
 }
 
@@ -249,6 +260,7 @@ void TimedInterruptSource::update_channel(int c, bool is_linked, int decrement)
 			// from high to low is amongst the included flips.
 			if(is_linked && num_flips + channels_[c].level >= 2) {
 				interrupts_ |= uint8_t(Interrupt::VariableFrequency);
+				programmable_level_ ^= true;
 			}
 			channels_[c].level ^= (num_flips & 1);
 
@@ -259,68 +271,67 @@ void TimedInterruptSource::update_channel(int c, bool is_linked, int decrement)
 	}
 }
 
-void TimedInterruptSource::run_for(Cycles cycles) {
-	// Update the 1Hz interrupt.
-	one_hz_offset_ -= cycles;
-	if(one_hz_offset_ <= Cycles(0)) {
+void TimedInterruptSource::run_for(Cycles duration) {
+	// Determine total number of ticks.
+	run_length_ += duration;
+	const Cycles cycles = run_length_.divide(global_divider_);
+	if(cycles == Cycles(0)) {
+		return;
+	}
+
+	// Update the two-second counter, from which the 1Hz, 50Hz and 1000Hz signals
+	// are derived.
+	const int previous_counter = two_second_counter_;
+	two_second_counter_ = (two_second_counter_ + cycles.as<int>()) % 500'000;
+
+	// Check for a 1Hz rollover.
+	if(previous_counter / 250'000 != two_second_counter_ / 250'000) {
 		interrupts_ |= uint8_t(Interrupt::OneHz);
-		one_hz_offset_ += clock_rate;
+	}
+
+	// Check for 1kHz or 50Hz rollover;
+	switch(rate_) {
+		default: break;
+		case InterruptRate::OnekHz:
+			if(previous_counter / 250 != two_second_counter_ / 250) {
+				interrupts_ |= uint8_t(Interrupt::VariableFrequency);
+				programmable_level_ ^= true;
+			}
+		break;
+		case InterruptRate::FiftyHz:
+			if(previous_counter / 5'000 != two_second_counter_ / 5'000) {
+				interrupts_ |= uint8_t(Interrupt::VariableFrequency);
+				programmable_level_ ^= true;
+			}
+		break;
 	}
 
 	// Update the two tone channels.
 	update_channel(0, rate_ == InterruptRate::ToneGenerator0, cycles.as<int>());
 	update_channel(1, rate_ == InterruptRate::ToneGenerator1, cycles.as<int>());
-
-	// Update the programmable-frequency interrupt.
-	if(rate_ < InterruptRate::ToneGenerator0) {
-		programmable_offset_ -= cycles.as<int>();
-		if(programmable_offset_ <= 0) {
-			if(programmable_level_) {
-				interrupts_ |= uint8_t(Interrupt::VariableFrequency);
-			}
-			programmable_level_ ^= true;
-			programmable_offset_ = programmble_reload(rate_);
-		}
-	}
 }
 
 Cycles TimedInterruptSource::get_next_sequence_point() const {
-	int result = one_hz_offset_.as<int>();
-
+	// Since both the 1kHz and 50Hz timers are integer dividers of the 1Hz timer, there's no need
+	// to factor that one in when determining the next sequence point for either of those.
 	switch(rate_) {
-		case InterruptRate::OnekHz:
-		case InterruptRate::FiftyHz:
-			result = std::min(result, programmable_offset_ + (!programmable_level_) * programmble_reload(rate_));
-		break;
+		default:
+		case InterruptRate::OnekHz:		return Cycles(250 - (two_second_counter_ % 250));
+		case InterruptRate::FiftyHz:	return Cycles(5000 - (two_second_counter_ % 5000));
+
 		case InterruptRate::ToneGenerator0:
 		case InterruptRate::ToneGenerator1: {
 			const auto &channel = channels_[int(rate_) - int(InterruptRate::ToneGenerator0)];
 			const int cycles_until_interrupt = channel.value + 1 + (!channel.level) * (channel.reload + 1);
-			result = std::min(result, cycles_until_interrupt);
-		} break;
-	}
 
-	return Cycles(result);
+			return Cycles(std::min(
+				250'000 - (two_second_counter_ % 250'000),
+				cycles_until_interrupt
+			));
+		}
+	}
 }
 
 uint8_t TimedInterruptSource::get_divider_state() {
-	bool programmable_flag = false;
-	switch(rate_) {
-		case InterruptRate::OnekHz:
-		case InterruptRate::FiftyHz:
-			programmable_flag = programmable_level_;
-		break;
-		case InterruptRate::ToneGenerator0:
-			programmable_flag = channels_[0].level;
-		break;
-		case InterruptRate::ToneGenerator1:
-			programmable_flag = channels_[1].level;
-		break;
-	}
-
-	// one_hz_offset_ counts downwards, so when it crosses the halfway mark
-	// it enters the high part of its wave.
-	return
-		(one_hz_offset_ < half_clock_rate ? 0x4 : 0x0) |
-		(programmable_flag ? 0x1 : 0x0);
+	return uint8_t((two_second_counter_ / 250'000) * 4 | programmable_level_);
 }

Machines/Enterprise/Dave.hpp

@@ -45,6 +45,10 @@ class Audio: public Outputs::Speaker::SampleSource {
 	private:
 		Concurrency::DeferringAsyncTaskQueue &audio_queue_;
 
+		// Global divider (i.e. 8MHz/12Mhz switch).
+		uint8_t global_divider_;
+		uint8_t global_divider_reload_ = 2;
+
 		// Tone channels.
 		struct Channel {
 			// User-set values.
@@ -147,12 +151,16 @@ class TimedInterruptSource {
 		static constexpr Cycles clock_rate{250000};
 		static constexpr Cycles half_clock_rate{125000};
 
+		// Global divider (i.e. 8MHz/12Mhz switch).
+		Cycles global_divider_ = Cycles(2);
+		Cycles run_length_;
+
 		// Interrupts that have fired since get_new_interrupts()
 		// was last called.
 		uint8_t interrupts_ = 0;
 
 		// A counter for the 1Hz interrupt.
-		Cycles one_hz_offset_ = clock_rate;
+		int two_second_counter_ = 0;
 
 		// A counter specific to the 1kHz and 50Hz timers, if in use.
 		enum class InterruptRate {
@@ -161,7 +169,6 @@ class TimedInterruptSource {
 			ToneGenerator0,
 			ToneGenerator1,
 		} rate_ = InterruptRate::OnekHz;
-		int programmable_offset_ = programmble_reload(InterruptRate::OnekHz);
 		bool programmable_level_ = false;
 
 		// A local duplicate of the counting state of the first two audio
@@ -173,13 +180,6 @@ class TimedInterruptSource {
 			bool level = false;
 		} channels_[2];
 		void update_channel(int c, bool is_linked, int decrement);
-		static constexpr int programmble_reload(InterruptRate rate) {
-			switch(rate) {
-				default: return 0;
-				case InterruptRate::OnekHz:		return 125;
-				case InterruptRate::FiftyHz:	return 2500;
-			}
-		}
 };
 
 }

Machines/Enterprise/Enterprise.cpp

@@ -65,7 +65,7 @@ namespace Enterprise {
 
 */
 
-template <bool has_disk_controller> class ConcreteMachine:
+template <bool has_disk_controller, bool is_6mhz> class ConcreteMachine:
 	public Activity::Source,
 	public Configurable::Device,
 	public CPU::Z80::BusHandler,
@@ -88,15 +88,23 @@ template <bool has_disk_controller> class ConcreteMachine:
 			return uint8_t(0x100 - ram_size / 0x4000);
 		}
 
+		static constexpr double clock_rate = is_6mhz ? 6'000'000.0 : 4'000'000.0;
+		using NickType =
+			std::conditional_t<is_6mhz,
+				JustInTimeActor<Nick, HalfCycles, 13478201, 5680000>,
+				JustInTimeActor<Nick, HalfCycles, 40434603, 11360000>>;
+
 	public:
-		ConcreteMachine([[maybe_unused]] const Analyser::Static::Enterprise::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
+		ConcreteMachine(const Analyser::Static::Enterprise::Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
 			min_ram_slot_(min_ram_slot(target)),
 			z80_(*this),
 			nick_(ram_.end() - 65536),
 			dave_audio_(audio_queue_),
 			speaker_(dave_audio_) {
-			// Request a clock of 4Mhz; this'll be mapped upwards for Nick and Dave elsewhere.
-			set_clock_rate(4'000'000);
+
+			// Request a clock of 4Mhz; this'll be mapped upwards for Nick and downwards for Dave elsewhere.
+			set_clock_rate(clock_rate);
+			speaker_.set_input_rate(float(clock_rate) / float(dave_divider));
 
 			ROM::Request request;
 			using Target = Analyser::Static::Enterprise::Target;
@@ -216,9 +224,6 @@ template <bool has_disk_controller> class ConcreteMachine:
 			page<2>(0x00);
 			page<3>(0x00);
 
-			// Set up audio.
-			speaker_.set_input_rate(250000.0f);	// TODO: a bigger number, and respect the programmable divider.
-
 			// Pass on any media.
 			insert_media(target.media);
 			if(!target.loading_command.empty()) {
@@ -270,26 +275,26 @@ template <bool has_disk_controller> class ConcreteMachine:
 				default: break;
 
 				// For non-video pauses, insert during the initial part of the bus cycle.
-				case CPU::Z80::PartialMachineCycle::ReadStart:
-				case CPU::Z80::PartialMachineCycle::WriteStart:
+				case PartialMachineCycle::ReadStart:
+				case PartialMachineCycle::WriteStart:
 					if(!is_video_[address >> 14] && wait_mode_ == WaitMode::OnAllAccesses) {
-						penalty = HalfCycles(2);
+						penalty = dave_delay_;
 					}
 				break;
-				case CPU::Z80::PartialMachineCycle::ReadOpcodeStart:
-					if(!is_video_[address >> 14] && wait_mode_ != WaitMode::None) {
-						penalty = HalfCycles(2);
-					} else {
+				case PartialMachineCycle::ReadOpcodeStart: {
+					if(is_video_[address >> 14]) {
 						// Query Nick for the amount of delay that would occur with one cycle left
 						// in this read opcode.
 						const auto delay_time = nick_.time_since_flush(HalfCycles(2));
 						const auto delay = nick_.last_valid()->get_time_until_z80_slot(delay_time);
 						penalty = nick_.back_map(delay, delay_time);
+					} else if(wait_mode_ != WaitMode::None) {
+						penalty = dave_delay_;
 					}
-				break;
+				} break;
 
 				// Video pauses: insert right at the end of the bus cycle.
-				case CPU::Z80::PartialMachineCycle::Write:
+				case PartialMachineCycle::Write:
 					// Ensure all video that should have been collected prior to
 					// this write has been.
 					if(is_video_[address >> 14]) {
@@ -297,7 +302,7 @@ template <bool has_disk_controller> class ConcreteMachine:
 					}
 					[[fallthrough]];
 
-				case CPU::Z80::PartialMachineCycle::Read:
+				case PartialMachineCycle::Read:
 					if(is_video_[address >> 14]) {
 						// Get delay, in Nick cycles, for a Z80 access that occurs in 0.5
 						// cycles from now (i.e. with one cycle left to run).
@@ -307,8 +312,8 @@ template <bool has_disk_controller> class ConcreteMachine:
 					}
 				break;
 
-				case CPU::Z80::PartialMachineCycle::Input:
-				case CPU::Z80::PartialMachineCycle::Output: {
+				case PartialMachineCycle::Input:
+				case PartialMachineCycle::Output: {
 					if((address & 0xf0) == 0x80) {
 						// Get delay, in Nick cycles, for a Z80 access that occurs in 0.5
 						// cycles from now (i.e. with one cycle left to run).
@@ -334,7 +339,11 @@ template <bool has_disk_controller> class ConcreteMachine:
 			switch(cycle.operation) {
 				default: break;
 
-				case CPU::Z80::PartialMachineCycle::Input:
+				case PartialMachineCycle::Interrupt:
+					*cycle.value = 0xff;
+				break;
+
+				case PartialMachineCycle::Input:
 					switch(address & 0xff) {
 						default:
 							LOG("Unhandled input from " << PADHEX(2) << (address & 0xff));
@@ -372,7 +381,7 @@ template <bool has_disk_controller> class ConcreteMachine:
 
 						case 0xb4:
 							*cycle.value =
-								(nick_->get_interrupt_line() ? 0x00 : 0x10) |
+								(nick_->get_interrupt_line() ? 0x10 : 0x00) |
 								dave_timer_->get_divider_state() |
 								interrupt_state_;
 						break;
@@ -399,7 +408,7 @@ template <bool has_disk_controller> class ConcreteMachine:
 					}
 				break;
 
-				case CPU::Z80::PartialMachineCycle::Output:
+				case PartialMachineCycle::Output:
 					switch(address & 0xff) {
 						default:
 							LOG("Unhandled output: " << PADHEX(2) << *cycle.value << " to " << PADHEX(2) << (address & 0xff));
@@ -430,6 +439,19 @@ template <bool has_disk_controller> class ConcreteMachine:
 						case 0xb2:	page<2>(*cycle.value);	break;
 						case 0xb3:	page<3>(*cycle.value);	break;
 
+						case 0xbf:
+							switch((*cycle.value >> 2)&3) {
+								default:	wait_mode_ = WaitMode::None;			break;
+								case 0:		wait_mode_ = WaitMode::OnAllAccesses;	break;
+								case 1:		wait_mode_ = WaitMode::OnM1;			break;
+							}
+
+							// Dave delays (i.e. those affecting memory areas not associated with Nick)
+							// are one cycle in 8Mhz mode, two cycles in 12Mhz mode.
+							dave_delay_ = HalfCycles(2 + (*cycle.value)&2);
+
+							[[fallthrough]];
+
 						case 0xa0:	case 0xa1:	case 0xa2:	case 0xa3:
 						case 0xa4:	case 0xa5:	case 0xa6:	case 0xa7:
 						case 0xa8:	case 0xa9:	case 0xaa:	case 0xab:
@@ -495,19 +517,11 @@ template <bool has_disk_controller> class ConcreteMachine:
 							// b1 = serial status out
 							LOG("TODO: serial output " << PADHEX(2) << *cycle.value);
 						break;
-						case 0xbf:
-							// TODO: onboard RAM, Dave 8/12Mhz select.
-							switch((*cycle.value >> 2)&3) {
-								default:	wait_mode_ = WaitMode::None;			break;
-								case 0:		wait_mode_ = WaitMode::OnAllAccesses;	break;
-								case 1:		wait_mode_ = WaitMode::OnM1;			break;
-							}
-						break;
 					}
 				break;
 
-				case CPU::Z80::PartialMachineCycle::Read:
-				case CPU::Z80::PartialMachineCycle::ReadOpcode:
+				case PartialMachineCycle::Read:
+				case PartialMachineCycle::ReadOpcode:
 					if(read_pointers_[address >> 14]) {
 						*cycle.value = read_pointers_[address >> 14][address];
 					} else {
@@ -515,7 +529,7 @@ template <bool has_disk_controller> class ConcreteMachine:
 					}
 				break;
 
-				case CPU::Z80::PartialMachineCycle::Write:
+				case PartialMachineCycle::Write:
 					if(write_pointers_[address >> 14]) {
 						write_pointers_[address >> 14][address] = *cycle.value;
 					}
@@ -588,7 +602,7 @@ template <bool has_disk_controller> class ConcreteMachine:
 			None,
 			OnM1,
 			OnAllAccesses
-		} wait_mode_ = WaitMode::None;
+		} wait_mode_ = WaitMode::OnAllAccesses;
 		bool is_video_[4]{};
 
 		// MARK: - ScanProducer
@@ -683,7 +697,7 @@ template <bool has_disk_controller> class ConcreteMachine:
 
 		// MARK: - Chips.
 		CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
-		JustInTimeActor<Nick, HalfCycles, 40434603, 11360000> nick_;
+		NickType nick_;
 		bool previous_nick_interrupt_line_ = false;
 		// Cf. timing guesses above.
 
@@ -692,12 +706,14 @@ template <bool has_disk_controller> class ConcreteMachine:
 		Outputs::Speaker::LowpassSpeaker<Dave::Audio> speaker_;
 		HalfCycles time_since_audio_update_;
 
-		// The following two should both use the same divider.
-		JustInTimeActor<Dave::TimedInterruptSource, HalfCycles, 1, 16> dave_timer_;
+		HalfCycles dave_delay_ = HalfCycles(2);
+
+		// The divider supplied to the JustInTimeActor and the manual divider used in
+		// update_audio() should match.
+		static constexpr int dave_divider = 8;
+		JustInTimeActor<Dave::TimedInterruptSource, HalfCycles, 1, dave_divider> dave_timer_;
 		inline void update_audio() {
-			// TODO: divide by only 8, letting Dave divide itself by a further 2 or 3
-			// as per its own register.
-			speaker_.run_for(audio_queue_, time_since_audio_update_.divide_cycles(Cycles(16)));
+			speaker_.run_for(audio_queue_, time_since_audio_update_.divide_cycles(Cycles(dave_divider)));
 		}
 
 		// MARK: - EXDos card.
@@ -731,10 +747,19 @@ Machine *Machine::Enterprise(const Analyser::Static::Target *target, const ROMMa
 	using Target = Analyser::Static::Enterprise::Target;
 	const Target *const enterprise_target = dynamic_cast<const Target *>(target);
 
-	if(enterprise_target->dos == Target::DOS::None)
-		return new Enterprise::ConcreteMachine<false>(*enterprise_target, rom_fetcher);
-	else
-		return new Enterprise::ConcreteMachine<true>(*enterprise_target, rom_fetcher);
+#define BuildMachine(exdos, sixmhz)																									\
+	if((enterprise_target->dos == Target::DOS::None) != exdos && (enterprise_target->speed == Target::Speed::SixMHz) == sixmhz) {	\
+		return new Enterprise::ConcreteMachine<exdos, sixmhz>(*enterprise_target, rom_fetcher);										\
+	}
+
+	BuildMachine(false, false);
+	BuildMachine(false, true);
+	BuildMachine(true, false);
+	BuildMachine(true, true);
+
+#undef BuildMachine
+
+	return nullptr;
 }
 
 Machine::~Machine() {}

Machines/Enterprise/Nick.hpp

@@ -94,9 +94,6 @@ class Nick {
 		bool vres_ = false;
 		bool reload_line_parameter_pointer_ = false;
 
-		// An accumulator for border output regions.
-		int border_duration_ = 0;
-
 		// The destination for new pixels.
 		static constexpr int allocation_size = 336;
 		static_assert((allocation_size % 16) == 0, "Allocation size must be a multiple of 16");

OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.h

@@ -47,6 +47,11 @@ typedef NS_ENUM(NSInteger, CSMachineEnterpriseModel) {
 	CSMachineEnterpriseModel256,
 };
 
+typedef NS_ENUM(NSInteger, CSMachineEnterpriseSpeed) {
+	CSMachineEnterpriseSpeed4MHz,
+	CSMachineEnterpriseSpeed6MHz
+};
+
 typedef NS_ENUM(NSInteger, CSMachineEnterpriseEXOS) {
 	CSMachineEnterpriseEXOSVersion21,
 	CSMachineEnterpriseEXOSVersion20,
@@ -120,7 +125,7 @@ typedef int Kilobytes;
 - (instancetype)initWithAppleIIgsModel:(CSMachineAppleIIgsModel)model memorySize:(Kilobytes)memorySize;
 - (instancetype)initWithAtariSTModel:(CSMachineAtariSTModel)model;
 - (instancetype)initWithElectronDFS:(BOOL)dfs adfs:(BOOL)adfs ap6:(BOOL)ap6 sidewaysRAM:(BOOL)sidewaysRAM;
-- (instancetype)initWithEnterpriseModel:(CSMachineEnterpriseModel)model exosVersion:(CSMachineEnterpriseEXOS)exosVersion basicVersion:(CSMachineEnterpriseBASIC)basicVersion dos:(CSMachineEnterpriseDOS)dos;
+- (instancetype)initWithEnterpriseModel:(CSMachineEnterpriseModel)model speed:(CSMachineEnterpriseSpeed)speed exosVersion:(CSMachineEnterpriseEXOS)exosVersion basicVersion:(CSMachineEnterpriseBASIC)basicVersion dos:(CSMachineEnterpriseDOS)dos;
 - (instancetype)initWithMacintoshModel:(CSMachineMacintoshModel)model;
 - (instancetype)initWithMSXRegion:(CSMachineMSXRegion)region hasDiskDrive:(BOOL)hasDiskDrive;
 - (instancetype)initWithOricModel:(CSMachineOricModel)model diskInterface:(CSMachineOricDiskInterface)diskInterface;

OSBindings/Mac/Clock Signal/Machine/StaticAnalyser/CSStaticAnalyser.mm

@@ -131,7 +131,7 @@
 	return self;
 }
 
-- (instancetype)initWithEnterpriseModel:(CSMachineEnterpriseModel)model exosVersion:(CSMachineEnterpriseEXOS)exosVersion basicVersion:(CSMachineEnterpriseBASIC)basicVersion dos:(CSMachineEnterpriseDOS)dos {
+- (instancetype)initWithEnterpriseModel:(CSMachineEnterpriseModel)model speed:(CSMachineEnterpriseSpeed)speed exosVersion:(CSMachineEnterpriseEXOS)exosVersion basicVersion:(CSMachineEnterpriseBASIC)basicVersion dos:(CSMachineEnterpriseDOS)dos {
 	self = [super init];
 	if(self) {
 		using Target = Analyser::Static::Enterprise::Target;
@@ -144,6 +144,12 @@
 			case CSMachineEnterpriseModel256:		target->model = Target::Model::Enterprise256;		break;
 		}
 
+		switch(speed) {
+			case CSMachineEnterpriseSpeed6MHz:		target->speed = Target::Speed::SixMHz;				break;
+			default:
+			case CSMachineEnterpriseSpeed4MHz:		target->speed = Target::Speed::FourMHz;				break;
+		}
+
 		switch(exosVersion) {
 			case CSMachineEnterpriseEXOSVersion21:	target->exos_version = Target::EXOSVersion::v21;	break;
 			default:

OSBindings/Mac/Clock Signal/MachinePicker/Base.lproj/MachinePicker.xib

@@ -322,8 +322,21 @@ Gw
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
+                                        <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="Lfl-5c-b8j">
+                                            <rect key="frame" x="67" y="149" width="77" height="25"/>
+                                            <popUpButtonCell key="cell" type="push" title="4 Mhz" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="4" imageScaling="axesIndependently" inset="2" selectedItem="5N6-tD-uN7" id="BU2-NJ-Kii">
+                                                <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
+                                                <font key="font" metaFont="menu"/>
+                                                <menu key="menu" id="ANK-p0-M77">
+                                                    <items>
+                                                        <menuItem title="4 Mhz" state="on" tag="4" id="5N6-tD-uN7"/>
+                                                        <menuItem title="6 Mhz" tag="6" id="bVT-qO-U7n"/>
+                                                    </items>
+                                                </menu>
+                                            </popUpButtonCell>
+                                        </popUpButton>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="nen-Za-7zH">
-                                            <rect key="frame" x="64" y="149" width="107" height="25"/>
+                                            <rect key="frame" x="64" y="119" width="107" height="25"/>
                                             <popUpButtonCell key="cell" type="push" title="Version 2.1" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="21" imageScaling="axesIndependently" inset="2" selectedItem="Qja-xZ-wVM" id="xGG-ri-8Sb">
                                                 <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                 <font key="font" metaFont="menu"/>
@@ -337,7 +350,7 @@ Gw
                                             </popUpButtonCell>
                                         </popUpButton>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="hIr-GH-7xi">
-                                            <rect key="frame" x="67" y="119" width="105" height="25"/>
+                                            <rect key="frame" x="67" y="89" width="105" height="25"/>
                                             <popUpButtonCell key="cell" type="push" title="Version 2.1" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="21" imageScaling="axesIndependently" inset="2" selectedItem="TME-cv-Jh1" id="9mQ-GW-lq9">
                                                 <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                 <font key="font" metaFont="menu"/>
@@ -352,20 +365,20 @@ Gw
                                             </popUpButtonCell>
                                         </popUpButton>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="syE-e7-TjU">
-                                            <rect key="frame" x="57" y="89" width="83" height="25"/>
-                                            <popUpButtonCell key="cell" type="push" title="EXDOS" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" borderStyle="borderAndBezel" tag="1" imageScaling="axesIndependently" inset="2" selectedItem="8rP-2w-PdU" id="NvO-Zm-2Rq">
+                                            <rect key="frame" x="57" y="59" width="83" height="25"/>
+                                            <popUpButtonCell key="cell" type="push" title="EXDOS" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" tag="1" imageScaling="axesIndependently" inset="2" selectedItem="8rP-2w-PdU" id="NvO-Zm-2Rq">
                                                 <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                 <font key="font" metaFont="menu"/>
                                                 <menu key="menu" title="DOS" id="sdr-al-7mi">
                                                     <items>
-                                                        <menuItem title="EXDOS" tag="1" id="8rP-2w-PdU"/>
-                                                        <menuItem title="None" state="on" id="qoS-KO-iEZ"/>
+                                                        <menuItem title="EXDOS" state="on" tag="1" id="8rP-2w-PdU"/>
+                                                        <menuItem title="None" id="qoS-KO-iEZ"/>
                                                     </items>
                                                 </menu>
                                             </popUpButtonCell>
                                         </popUpButton>
                                         <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ykc-W1-YaS">
-                                            <rect key="frame" x="18" y="155" width="43" height="16"/>
+                                            <rect key="frame" x="18" y="125" width="43" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="EXOS:" id="gUC-PN-zVL">
                                                 <font key="font" metaFont="system"/>
                                                 <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@@ -381,7 +394,7 @@ Gw
                                             </textFieldCell>
                                         </textField>
                                         <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="dzd-tH-BjX">
-                                            <rect key="frame" x="18" y="125" width="46" height="16"/>
+                                            <rect key="frame" x="18" y="95" width="46" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="BASIC:" id="ai1-oR-X6Y">
                                                 <font key="font" metaFont="system"/>
                                                 <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@@ -389,13 +402,21 @@ Gw
                                             </textFieldCell>
                                         </textField>
                                         <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="pxr-Bq-yh0">
-                                            <rect key="frame" x="18" y="95" width="36" height="16"/>
+                                            <rect key="frame" x="18" y="65" width="36" height="16"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="DOS:" id="NFk-cp-DfS">
                                                 <font key="font" metaFont="system"/>
                                                 <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
                                                 <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
                                             </textFieldCell>
                                         </textField>
+                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="rHr-bh-QMV">
+                                            <rect key="frame" x="17" y="155" width="47" height="16"/>
+                                            <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Speed:" id="sAw-C9-Sf7">
+                                                <font key="font" metaFont="system"/>
+                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                                                <color key="backgroundColor" name="controlColor" catalog="System" colorSpace="catalog"/>
+                                            </textFieldCell>
+                                        </textField>
                                     </subviews>
                                     <constraints>
                                         <constraint firstItem="dzd-tH-BjX" firstAttribute="centerY" secondItem="hIr-GH-7xi" secondAttribute="centerY" id="3TV-RU-Kgh"/>
@@ -403,11 +424,13 @@ Gw
                                         <constraint firstItem="frx-nk-c3P" firstAttribute="centerY" secondItem="PhH-bu-pb5" secondAttribute="centerY" id="6Wc-aR-wuL"/>
                                         <constraint firstItem="dzd-tH-BjX" firstAttribute="leading" secondItem="1cs-PX-RAH" secondAttribute="leading" constant="20" symbolic="YES" id="7RZ-Om-TAa"/>
                                         <constraint firstItem="ykc-W1-YaS" firstAttribute="centerY" secondItem="nen-Za-7zH" secondAttribute="centerY" id="CLa-6E-8BB"/>
+                                        <constraint firstItem="nen-Za-7zH" firstAttribute="top" secondItem="Lfl-5c-b8j" secondAttribute="bottom" constant="10" symbolic="YES" id="Df8-qv-3dY"/>
                                         <constraint firstItem="PhH-bu-pb5" firstAttribute="leading" secondItem="frx-nk-c3P" secondAttribute="trailing" constant="8" symbolic="YES" id="ENF-TY-TQ7"/>
                                         <constraint firstItem="nen-Za-7zH" firstAttribute="leading" secondItem="ykc-W1-YaS" secondAttribute="trailing" constant="8" symbolic="YES" id="GWR-VI-9PG"/>
                                         <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="syE-e7-TjU" secondAttribute="bottom" constant="20" symbolic="YES" id="K3s-FA-zMB"/>
                                         <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="PhH-bu-pb5" secondAttribute="trailing" constant="20" symbolic="YES" id="LwB-ef-uF4"/>
                                         <constraint firstItem="PhH-bu-pb5" firstAttribute="top" secondItem="1cs-PX-RAH" secondAttribute="top" constant="20" symbolic="YES" id="Myt-i4-jVq"/>
+                                        <constraint firstItem="Lfl-5c-b8j" firstAttribute="top" secondItem="PhH-bu-pb5" secondAttribute="bottom" constant="10" symbolic="YES" id="Nl3-hL-jwg"/>
                                         <constraint firstItem="pxr-Bq-yh0" firstAttribute="leading" secondItem="1cs-PX-RAH" secondAttribute="leading" constant="20" symbolic="YES" id="Qzp-IY-Pa0"/>
                                         <constraint firstItem="PhH-bu-pb5" firstAttribute="leading" secondItem="frx-nk-c3P" secondAttribute="trailing" constant="8" symbolic="YES" id="T3e-u7-fiQ"/>
                                         <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="syE-e7-TjU" secondAttribute="trailing" constant="20" symbolic="YES" id="TEX-Nw-y2K"/>
@@ -415,11 +438,13 @@ Gw
                                         <constraint firstItem="pxr-Bq-yh0" firstAttribute="centerY" secondItem="syE-e7-TjU" secondAttribute="centerY" id="UYw-uz-Am0"/>
                                         <constraint firstItem="hIr-GH-7xi" firstAttribute="top" secondItem="nen-Za-7zH" secondAttribute="bottom" constant="10" symbolic="YES" id="VOc-2v-s3u"/>
                                         <constraint firstItem="syE-e7-TjU" firstAttribute="top" secondItem="hIr-GH-7xi" secondAttribute="bottom" constant="10" symbolic="YES" id="W9S-on-Heq"/>
-                                        <constraint firstItem="nen-Za-7zH" firstAttribute="top" secondItem="PhH-bu-pb5" secondAttribute="bottom" constant="10" symbolic="YES" id="Yes-o3-V0m"/>
+                                        <constraint firstItem="rHr-bh-QMV" firstAttribute="leading" secondItem="1cs-PX-RAH" secondAttribute="leading" constant="19" id="XZf-lB-NnA"/>
                                         <constraint firstItem="ykc-W1-YaS" firstAttribute="leading" secondItem="1cs-PX-RAH" secondAttribute="leading" constant="20" symbolic="YES" id="bAP-lx-pdi"/>
                                         <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="nen-Za-7zH" secondAttribute="trailing" constant="20" symbolic="YES" id="eEI-5Q-TnO"/>
                                         <constraint firstItem="syE-e7-TjU" firstAttribute="leading" secondItem="pxr-Bq-yh0" secondAttribute="trailing" constant="8" symbolic="YES" id="fmM-Ma-Jyu"/>
                                         <constraint firstItem="hIr-GH-7xi" firstAttribute="leading" secondItem="dzd-tH-BjX" secondAttribute="trailing" constant="8" symbolic="YES" id="jDQ-TF-Ogf"/>
+                                        <constraint firstItem="rHr-bh-QMV" firstAttribute="centerY" secondItem="Lfl-5c-b8j" secondAttribute="centerY" id="mnp-JF-dVQ"/>
+                                        <constraint firstItem="Lfl-5c-b8j" firstAttribute="leading" secondItem="rHr-bh-QMV" secondAttribute="trailing" constant="8" symbolic="YES" id="yfb-SL-v1H"/>
                                     </constraints>
                                 </view>
                             </tabViewItem>
@@ -874,6 +899,7 @@ Gw
                 <outlet property="enterpriseDOSButton" destination="syE-e7-TjU" id="sCW-Bj-ZTW"/>
                 <outlet property="enterpriseEXOSButton" destination="nen-Za-7zH" id="NwS-ua-FdA"/>
                 <outlet property="enterpriseModelButton" destination="PhH-bu-pb5" id="8wD-sW-aBw"/>
+                <outlet property="enterpriseSpeedButton" destination="Lfl-5c-b8j" id="ClN-yN-Nbx"/>
                 <outlet property="machineNameTable" destination="3go-Eb-GOy" id="Ppf-S0-IP1"/>
                 <outlet property="machineSelector" destination="VUb-QG-x7c" id="crR-hB-jGd"/>
                 <outlet property="macintoshModelTypeButton" destination="xa6-NA-JY5" id="2jX-PY-v2z"/>

OSBindings/Mac/Clock Signal/MachinePicker/MachinePicker.swift

@@ -38,6 +38,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 
 	// MARK: - Enterprise properties
 	@IBOutlet var enterpriseModelButton: NSPopUpButton!
+	@IBOutlet var enterpriseSpeedButton: NSPopUpButton!
 	@IBOutlet var enterpriseEXOSButton: NSPopUpButton!
 	@IBOutlet var enterpriseBASICButton: NSPopUpButton!
 	@IBOutlet var enterpriseDOSButton: NSPopUpButton!
@@ -110,6 +111,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 
 		// Enterprise settings
 		enterpriseModelButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseModel"))
+		enterpriseSpeedButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseSpeed"))
 		enterpriseEXOSButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseEXOSVersion"))
 		enterpriseBASICButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseBASICVersion"))
 		enterpriseDOSButton.selectItem(withTag: standardUserDefaults.integer(forKey: "new.enterpriseDOS"))
@@ -166,6 +168,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 
 		// Enterprise settings
 		standardUserDefaults.set(enterpriseModelButton.selectedTag(), forKey: "new.enterpriseModel")
+		standardUserDefaults.set(enterpriseSpeedButton.selectedTag(), forKey: "new.enterpriseSpeed")
 		standardUserDefaults.set(enterpriseEXOSButton.selectedTag(), forKey: "new.enterpriseEXOSVersion")
 		standardUserDefaults.set(enterpriseBASICButton.selectedTag(), forKey: "new.enterpriseBASICVersion")
 		standardUserDefaults.set(enterpriseDOSButton.selectedTag(), forKey: "new.enterpriseDOS")
@@ -253,14 +256,14 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 					default:	model = .ROM00
 				}
 
-				let memorySize = Kilobytes(appleIIgsMemorySizeButton.selectedItem!.tag)
+				let memorySize = Kilobytes(appleIIgsMemorySizeButton.selectedTag())
 				return CSStaticAnalyser(appleIIgsModel: model, memorySize: memorySize)
 
 			case "atarist":
 				return CSStaticAnalyser(atariSTModel: .model512k)
 
 			case "cpc":
-				switch cpcModelTypeButton.selectedItem!.tag {
+				switch cpcModelTypeButton.selectedTag() {
 					case 464:	return CSStaticAnalyser(amstradCPCModel: .model464)
 					case 664:	return CSStaticAnalyser(amstradCPCModel: .model664)
 					case 6128:	fallthrough
@@ -276,15 +279,22 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 
 			case "enterprise":
 				var model: CSMachineEnterpriseModel = .model128
-				switch enterpriseModelButton.selectedItem!.tag {
+				switch enterpriseModelButton.selectedTag() {
 					case 64:	model = .model64
 					case 256:	model = .model256
 					case 128:	fallthrough
 					default:	model = .model128
 				}
 
+				var speed: CSMachineEnterpriseSpeed = .speed4MHz
+				switch enterpriseSpeedButton.selectedTag() {
+					case 6:		speed = .speed6MHz
+					case 4:		fallthrough
+					default:	speed = .speed4MHz
+				}
+
 				var exos: CSMachineEnterpriseEXOS = .version21
-				switch enterpriseEXOSButton.selectedItem!.tag {
+				switch enterpriseEXOSButton.selectedTag() {
 					case 10:	exos = .version10
 					case 20:	exos = .version20
 					case 21:	fallthrough
@@ -307,10 +317,10 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 					default:	dos = .dosNone
 				}
 
-				return CSStaticAnalyser(enterpriseModel: model, exosVersion: exos, basicVersion: basic, dos: dos)
+				return CSStaticAnalyser(enterpriseModel: model, speed: speed, exosVersion: exos, basicVersion: basic, dos: dos)
 
 			case "mac":
-				switch macintoshModelTypeButton.selectedItem!.tag {
+				switch macintoshModelTypeButton.selectedTag() {
 					case 0:		return CSStaticAnalyser(macintoshModel: .model128k)
 					case 1:		return CSStaticAnalyser(macintoshModel: .model512k)
 					case 2:		return CSStaticAnalyser(macintoshModel: .model512ke)
@@ -320,7 +330,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 
 			case "msx":
 				let hasDiskDrive = msxHasDiskDriveButton.state == .on
-				switch msxRegionButton.selectedItem!.tag {
+				switch msxRegionButton.selectedTag() {
 					case 2:
 						return CSStaticAnalyser(msxRegion: .japanese, hasDiskDrive: hasDiskDrive)
 					case 1:
@@ -341,7 +351,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 
 				}
 				var model: CSMachineOricModel = .oric1
-				switch oricModelTypeButton.selectedItem!.tag {
+				switch oricModelTypeButton.selectedTag() {
 					case 1:		model = .oricAtmos
 					case 2:		model = .pravetz
 					default:	break
@@ -351,7 +361,7 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 
 			case "spectrum":
 				var model: CSMachineSpectrumModel = .plus2a
-				switch spectrumModelTypeButton.selectedItem!.tag {
+				switch spectrumModelTypeButton.selectedTag() {
 					case 16:	model = .sixteenK
 					case 48:	model = .fortyEightK
 					case 128:	model = .oneTwoEightK
@@ -364,9 +374,9 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 				return CSStaticAnalyser(spectrumModel: model)
 
 			case "vic20":
-				let memorySize = Kilobytes(vic20MemorySizeButton.selectedItem!.tag)
+				let memorySize = Kilobytes(vic20MemorySizeButton.selectedTag())
 				let hasC1540 = vic20HasC1540Button.state == .on
-				switch vic20RegionButton.selectedItem!.tag {
+				switch vic20RegionButton.selectedTag() {
 					case 1:
 						return CSStaticAnalyser(vic20Region: .american, memorySize: memorySize, hasC1540: hasC1540)
 					case 2:
@@ -381,10 +391,10 @@ class MachinePicker: NSObject, NSTableViewDataSource, NSTableViewDelegate {
 				}
 
 			case "zx80":
-				return CSStaticAnalyser(zx80MemorySize: Kilobytes(zx80MemorySizeButton.selectedItem!.tag), useZX81ROM: zx80UsesZX81ROMButton.state == .on)
+				return CSStaticAnalyser(zx80MemorySize: Kilobytes(zx80MemorySizeButton.selectedTag()), useZX81ROM: zx80UsesZX81ROMButton.state == .on)
 
 			case "zx81":
-				return CSStaticAnalyser(zx81MemorySize: Kilobytes(zx81MemorySizeButton.selectedItem!.tag))
+				return CSStaticAnalyser(zx81MemorySize: Kilobytes(zx81MemorySizeButton.selectedTag()))
 
 			default: return CSStaticAnalyser()
 		}

OSBindings/Mac/Clock SignalTests/EnterpriseDaveTests.mm

@@ -23,78 +23,80 @@
 	_interruptSource = std::make_unique<Enterprise::Dave::TimedInterruptSource>();
 }
 
-- (void)performTestExpectedToggles:(int)expectedToggles expectedInterrupts:(int)expectedInterrupts {
-	// Check that the programmable timer flag toggles at a rate
-	// of 2kHz, causing 1000 interrupts, and that sequence points
-	// are properly predicted.
+/// Tests that the programmable timer flag toggles and produces interrupts
+/// at the rate specified, and that the flag toggles when interrupts are signalled.
+- (void)performTestExpectedInterrupts:(double)expectedInterruptsPerSecond mode:(int)mode {
+	// If a programmable timer mode is requested, synchronise both channels.
+	if(mode >= 2) {
+		_interruptSource->write(0xa7, 3);
+		_interruptSource->run_for(Cycles(2));
+	}
+
+	// Set mode (and disable sync, if it was applied).
+	_interruptSource->write(0xa7, mode << 5);
+
 	int toggles = 0;
 	int interrupts = 0;
-	uint8_t dividerState = _interruptSource->get_divider_state();
+	uint8_t dividerState = _interruptSource->get_divider_state() & 1;
 	int nextSequencePoint = _interruptSource->get_next_sequence_point().as<int>();
-	for(int c = 0; c < 250000; c++) {
-		// Advance one cycle. Clock is 250,000 Hz.
-		_interruptSource->run_for(Cycles(1));
-
-		const uint8_t newDividerState = _interruptSource->get_divider_state();
-		if((dividerState^newDividerState)&0x1) {
-			++toggles;
-		}
-		dividerState = newDividerState;
 
+	for(int c = 0; c < 250000 * 5; c++) {
+		// Advance one cycle. Clock is 500,000 Hz.
+		_interruptSource->run_for(Cycles(2));
 		--nextSequencePoint;
 
+		// Check for a status bit change.
+		const uint8_t newDividerState = _interruptSource->get_divider_state();
+		const bool didToggle = (dividerState^newDividerState)&0x1;
+		dividerState = newDividerState;
+		toggles += didToggle;
+
 		// Check for the relevant interrupt.
 		const uint8_t newInterrupts = _interruptSource->get_new_interrupts();
-		if(newInterrupts & 0x02) {
-			++interrupts;
+		if(newInterrupts) {
 			XCTAssertEqual(nextSequencePoint, 0);
-			XCTAssertEqual(dividerState&0x1, 0);
 			nextSequencePoint = _interruptSource->get_next_sequence_point().as<int>();
-		}
 
-		// Failing that, confirm that the other interrupt happend.
-		if(!nextSequencePoint) {
-			XCTAssertTrue(newInterrupts & 0x08);
-			nextSequencePoint = _interruptSource->get_next_sequence_point().as<int>();
+			if(newInterrupts & 0x02) {
+				++interrupts;
+				XCTAssertTrue(didToggle);
+			} else {
+				// Failing that, confirm that the other interrupt happend.
+				XCTAssertTrue(newInterrupts & 0x08);
+			}
 		}
 
 		XCTAssertEqual(nextSequencePoint, _interruptSource->get_next_sequence_point().as<int>(), @"At cycle %d", c);
 	}
 
-	XCTAssertEqual(toggles, expectedToggles);
-	XCTAssertEqual(interrupts, expectedInterrupts);
+	XCTAssertEqual(toggles, int(expectedInterruptsPerSecond * 5.0));
+	XCTAssertEqual(interrupts, int(expectedInterruptsPerSecond * 5.0));
 }
 
 - (void)test1kHzTimer {
-	// Set 1kHz timer.
-	_interruptSource->write(7, 0 << 5);
-	[self performTestExpectedToggles:2000 expectedInterrupts:1000];
+	[self performTestExpectedInterrupts:1000.0 mode:0];
 }
 
 - (void)test50HzTimer {
-	// Set 50Hz timer.
-	_interruptSource->write(7, 1 << 5);
-	[self performTestExpectedToggles:100 expectedInterrupts:50];
+	[self performTestExpectedInterrupts:50.0 mode:1];
 }
 
 - (void)testTone0Timer {
 	// Set tone generator 0 as the interrupt source, with a divider of 137;
 	// apply sync momentarily.
-	_interruptSource->write(7, 2 << 5);
 	_interruptSource->write(0, 137);
 	_interruptSource->write(1, 0);
 
-	[self performTestExpectedToggles:250000/138 expectedInterrupts:250000/(138*2)];
+	[self performTestExpectedInterrupts:250000.0/(138.0 * 2.0) mode:2];
 }
 
 - (void)testTone1Timer {
 	// Set tone generator 1 as the interrupt source, with a divider of 961;
 	// apply sync momentarily.
-	_interruptSource->write(7, 3 << 5);
 	_interruptSource->write(2, 961 & 0xff);
 	_interruptSource->write(3, (961 >> 8) & 0xff);
 
-	[self performTestExpectedToggles:250000/961 expectedInterrupts:250000/(961*2)];
+	[self performTestExpectedInterrupts:250000.0/(962.0 * 2.0) mode:3];
 }
 
 @end

OSBindings/Qt/mainwindow.cpp

@@ -1073,6 +1073,11 @@ void MainWindow::start_enterprise() {
 		case 2:		target->model = Target::Model::Enterprise256;	break;
 	}
 
+	switch(ui->enterpriseSpeedComboBox->currentIndex()) {
+		default:	target->speed = Target::Speed::FourMHz;	break;
+		case 1:		target->speed = Target::Speed::SixMHz;	break;
+	}
+
 	switch(ui->enterpriseEXOSComboBox->currentIndex()) {
 		default:	target->exos_version = Target::EXOSVersion::v10;	break;
 		case 1:		target->exos_version = Target::EXOSVersion::v20;	break;
@@ -1252,6 +1257,7 @@ void MainWindow::launchTarget(std::unique_ptr<Analyser::Static::Target> &&target
 																		\
 	/* Enterprise. */													\
 	ComboBox(enterpriseModelComboBox, "enterprise.model");				\
+	ComboBox(enterpriseSpeedComboBox, "enterprise.speed");				\
 	ComboBox(enterpriseEXOSComboBox, "enterprise.exos");				\
 	ComboBox(enterpriseBASICComboBox, "enterprise.basic");				\
 	ComboBox(enterpriseDOSComboBox, "enterprise.dos");					\
@@ -1309,6 +1315,7 @@ void MainWindow::restoreSelections() {
 // MARK: - Activity observation
 
 void MainWindow::addActivityObserver() {
+	ledStatuses.clear();
 	auto activitySource = machine->activity_source();
 	if(!activitySource) return;
 

OSBindings/Qt/mainwindow.ui

@@ -27,7 +27,7 @@
     <item>
      <widget class="QTabWidget" name="machineSelectionTabs">
       <property name="currentIndex">
-       <number>1</number>
+       <number>5</number>
       </property>
       <widget class="QWidget" name="appleIITab">
        <attribute name="title">
@@ -346,13 +346,34 @@
              </widget>
             </item>
             <item row="1" column="0">
+             <widget class="QLabel" name="enterpriseSpeedLabel">
+              <property name="text">
+               <string>Speed:</string>
+              </property>
+             </widget>
+            </item>
+            <item row="1" column="1">
+             <widget class="QComboBox" name="enterpriseSpeedComboBox">
+              <item>
+               <property name="text">
+                <string>4 MHz</string>
+               </property>
+              </item>
+              <item>
+               <property name="text">
+                <string>6 MHz</string>
+               </property>
+              </item>
+             </widget>
+            </item>
+            <item row="2" column="0">
              <widget class="QLabel" name="enterpriseEXOSLabel">
               <property name="text">
                <string>EXOS:</string>
               </property>
              </widget>
             </item>
-            <item row="1" column="1">
+            <item row="2" column="1">
              <widget class="QComboBox" name="enterpriseEXOSComboBox">
               <item>
                <property name="text">
@@ -371,14 +392,14 @@
               </item>
              </widget>
             </item>
-            <item row="2" column="0">
+            <item row="3" column="0">
              <widget class="QLabel" name="enterpriseBASICLabel">
               <property name="text">
                <string>BASIC:</string>
               </property>
              </widget>
             </item>
-            <item row="2" column="1">
+            <item row="3" column="1">
              <widget class="QComboBox" name="enterpriseBASICComboBox">
               <item>
                <property name="text">
@@ -402,14 +423,14 @@
               </item>
              </widget>
             </item>
-            <item row="3" column="0">
+            <item row="4" column="0">
              <widget class="QLabel" name="enterpriseDOSLabel">
               <property name="text">
                <string>DOS:</string>
               </property>
              </widget>
             </item>
-            <item row="3" column="1">
+            <item row="4" column="1">
              <widget class="QComboBox" name="enterpriseDOSComboBox">
               <item>
                <property name="text">