Merge pull request #635 from TomHarte/Cleanup

Improves code quality, particularly the NSDocument subclass.

Analyser/Dynamic/MultiMachine/MultiMachine.cpp

@@ -59,6 +59,11 @@ KeyboardMachine::Machine *MultiMachine::keyboard_machine() {
 	}
 }
 
+MouseMachine::Machine *MultiMachine::mouse_machine() {
+	// TODO.
+	return nullptr;
+}
+
 Configurable::Device *MultiMachine::configurable_device() {
 	if(has_picked_) {
 		return machines_.front()->configurable_device();

Analyser/Dynamic/MultiMachine/MultiMachine.hpp

@@ -54,6 +54,7 @@ class MultiMachine: public ::Machine::DynamicMachine, public MultiCRTMachine::De
 		Configurable::Device *configurable_device() override;
 		CRTMachine::Machine *crt_machine() override;
 		JoystickMachine::Machine *joystick_machine() override;
+		MouseMachine::Machine *mouse_machine() override;
 		KeyboardMachine::Machine *keyboard_machine() override;
 		MediaTarget::Machine *media_target() override;
 		void *raw_pointer() override;

Analyser/Machines.hpp

@@ -17,6 +17,7 @@ enum class Machine {
 	Atari2600,
 	ColecoVision,
 	Electron,
+	Macintosh,
 	MasterSystem,
 	MSX,
 	Oric,

Analyser/Static/MSX/StaticAnalyser.cpp

@@ -290,6 +290,7 @@ Analyser::Static::TargetList Analyser::Static::MSX::GetTargets(const Media &medi
 	target->region = target->media.tapes.empty() ? Target::Region::USA : Target::Region::Europe;
 
 	// Blindly accept disks for now.
+	// TODO: how to spot an MSX disk?
 	target->media.disks = media.disks;
 	target->has_disk_drive = !media.disks.empty();
 

Analyser/Static/Macintosh/StaticAnalyser.cpp

@@ -0,0 +1,26 @@
+//
+//  StaticAnalyser.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 02/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "StaticAnalyser.hpp"
+#include "Target.hpp"
+
+Analyser::Static::TargetList Analyser::Static::Macintosh::GetTargets(const Media &media, const std::string &file_name, TargetPlatform::IntType potential_platforms) {
+	// This analyser can comprehend disks only.
+	if(media.disks.empty()) return {};
+
+	// If there is at least one disk, wave it through.
+	Analyser::Static::TargetList targets;
+
+	using Target = Analyser::Static::Macintosh::Target;
+	auto *target = new Target;
+	target->machine = Analyser::Machine::Macintosh;
+	target->media = media;
+	targets.push_back(std::unique_ptr<Analyser::Static::Target>(target));
+
+	return targets;
+}

Analyser/Static/Macintosh/StaticAnalyser.hpp

@@ -0,0 +1,27 @@
+//
+//  StaticAnalyser.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 02/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef Analyser_Static_Macintosh_StaticAnalyser_hpp
+#define Analyser_Static_Macintosh_StaticAnalyser_hpp
+
+#include "../StaticAnalyser.hpp"
+#include "../../../Storage/TargetPlatforms.hpp"
+#include <string>
+
+namespace Analyser {
+namespace Static {
+namespace Macintosh {
+
+TargetList GetTargets(const Media &media, const std::string &file_name, TargetPlatform::IntType potential_platforms);
+
+}
+}
+}
+
+
+#endif /* Analyser_Static_Macintosh_StaticAnalyser_hpp */

Analyser/Static/Macintosh/Target.hpp

@@ -0,0 +1,31 @@
+//
+//  Target.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 03/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef Analyser_Static_Macintosh_Target_h
+#define Analyser_Static_Macintosh_Target_h
+
+namespace Analyser {
+namespace Static {
+namespace Macintosh {
+
+struct Target: public ::Analyser::Static::Target {
+	enum class Model {
+		Mac128k,
+		Mac512k,
+		Mac512ke,
+		MacPlus
+	};
+
+	Model model = Model::Mac512ke;
+};
+
+}
+}
+}
+
+#endif /* Analyser_Static_Macintosh_Target_h */

Analyser/Static/StaticAnalyser.cpp

@@ -21,6 +21,7 @@
 #include "Coleco/StaticAnalyser.hpp"
 #include "Commodore/StaticAnalyser.hpp"
 #include "DiskII/StaticAnalyser.hpp"
+#include "Macintosh/StaticAnalyser.hpp"
 #include "MSX/StaticAnalyser.hpp"
 #include "Oric/StaticAnalyser.hpp"
 #include "Sega/StaticAnalyser.hpp"
@@ -35,6 +36,7 @@
 #include "../../Storage/Disk/DiskImage/Formats/AppleDSK.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/CPCDSK.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/D64.hpp"
+#include "../../Storage/Disk/DiskImage/Formats/MacintoshIMG.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/G64.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/DMK.hpp"
 #include "../../Storage/Disk/DiskImage/Formats/HFE.hpp"
@@ -85,34 +87,37 @@ static Media GetMediaAndPlatforms(const std::string &file_name, TargetPlatform::
 		TryInsert(list, class, platforms)	\
 	}
 
-	Format("80", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)										// 80
-	Format("81", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)										// 81
-	Format("a26", result.cartridges, Cartridge::BinaryDump, TargetPlatform::Atari2600)						// A26
-	Format("adf", result.disks, Disk::DiskImageHolder<Storage::Disk::AcornADF>, TargetPlatform::Acorn)		// ADF
-	Format("bin", result.cartridges, Cartridge::BinaryDump, TargetPlatform::AllCartridge)					// BIN
-	Format("cas", result.tapes, Tape::CAS, TargetPlatform::MSX)												// CAS
-	Format("cdt", result.tapes, Tape::TZX, TargetPlatform::AmstradCPC)										// CDT
-	Format("col", result.cartridges, Cartridge::BinaryDump, TargetPlatform::ColecoVision)					// COL
-	Format("csw", result.tapes, Tape::CSW, TargetPlatform::AllTape)											// CSW
-	Format("d64", result.disks, Disk::DiskImageHolder<Storage::Disk::D64>, TargetPlatform::Commodore)		// D64
-	Format("dmk", result.disks, Disk::DiskImageHolder<Storage::Disk::DMK>, TargetPlatform::MSX)				// DMK
-	Format("do", result.disks, Disk::DiskImageHolder<Storage::Disk::AppleDSK>, TargetPlatform::DiskII)		// DO
-	Format("dsd", result.disks, Disk::DiskImageHolder<Storage::Disk::SSD>, TargetPlatform::Acorn)			// DSD
-	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::CPCDSK>, TargetPlatform::AmstradCPC)	// DSK (Amstrad CPC)
-	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::AppleDSK>, TargetPlatform::DiskII)		// DSK (Apple)
-	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::MSXDSK>, TargetPlatform::MSX)			// DSK (MSX)
-	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::OricMFMDSK>, TargetPlatform::Oric)		// DSK (Oric)
-	Format("g64", result.disks, Disk::DiskImageHolder<Storage::Disk::G64>, TargetPlatform::Commodore)		// G64
+	Format("80", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)											// 80
+	Format("81", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)											// 81
+	Format("a26", result.cartridges, Cartridge::BinaryDump, TargetPlatform::Atari2600)							// A26
+	Format("adf", result.disks, Disk::DiskImageHolder<Storage::Disk::AcornADF>, TargetPlatform::Acorn)			// ADF
+	Format("bin", result.cartridges, Cartridge::BinaryDump, TargetPlatform::AllCartridge)						// BIN (cartridge dump)
+	Format("cas", result.tapes, Tape::CAS, TargetPlatform::MSX)													// CAS
+	Format("cdt", result.tapes, Tape::TZX, TargetPlatform::AmstradCPC)											// CDT
+	Format("col", result.cartridges, Cartridge::BinaryDump, TargetPlatform::ColecoVision)						// COL
+	Format("csw", result.tapes, Tape::CSW, TargetPlatform::AllTape)												// CSW
+	Format("d64", result.disks, Disk::DiskImageHolder<Storage::Disk::D64>, TargetPlatform::Commodore)			// D64
+	Format("dmk", result.disks, Disk::DiskImageHolder<Storage::Disk::DMK>, TargetPlatform::MSX)					// DMK
+	Format("do", result.disks, Disk::DiskImageHolder<Storage::Disk::AppleDSK>, TargetPlatform::DiskII)			// DO
+	Format("dsd", result.disks, Disk::DiskImageHolder<Storage::Disk::SSD>, TargetPlatform::Acorn)				// DSD
+	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::CPCDSK>, TargetPlatform::AmstradCPC)		// DSK (Amstrad CPC)
+	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::AppleDSK>, TargetPlatform::DiskII)			// DSK (Apple II)
+	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::MacintoshIMG>, TargetPlatform::Macintosh)	// DSK (Macintosh)
+	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::MSXDSK>, TargetPlatform::MSX)				// DSK (MSX)
+	Format("dsk", result.disks, Disk::DiskImageHolder<Storage::Disk::OricMFMDSK>, TargetPlatform::Oric)			// DSK (Oric)
+	Format("g64", result.disks, Disk::DiskImageHolder<Storage::Disk::G64>, TargetPlatform::Commodore)			// G64
 	Format(	"hfe",
 			result.disks,
 			Disk::DiskImageHolder<Storage::Disk::HFE>,
 			TargetPlatform::Acorn | TargetPlatform::AmstradCPC | TargetPlatform::Commodore | TargetPlatform::Oric)
 			// HFE (TODO: switch to AllDisk once the MSX stops being so greedy)
-	Format("nib", result.disks, Disk::DiskImageHolder<Storage::Disk::NIB>, TargetPlatform::DiskII)			// NIB
-	Format("o", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)										// O
-	Format("p", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)										// P
-	Format("po", result.disks, Disk::DiskImageHolder<Storage::Disk::AppleDSK>, TargetPlatform::DiskII)		// PO
-	Format("p81", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)										// P81
+	Format("img", result.disks, Disk::DiskImageHolder<Storage::Disk::MacintoshIMG>, TargetPlatform::Macintosh)		// IMG (DiskCopy 4.2)
+	Format("image", result.disks, Disk::DiskImageHolder<Storage::Disk::MacintoshIMG>, TargetPlatform::Macintosh)	// IMG (DiskCopy 4.2)
+	Format("nib", result.disks, Disk::DiskImageHolder<Storage::Disk::NIB>, TargetPlatform::DiskII)				// NIB
+	Format("o", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)											// O
+	Format("p", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)											// P
+	Format("po", result.disks, Disk::DiskImageHolder<Storage::Disk::AppleDSK>, TargetPlatform::DiskII)			// PO
+	Format("p81", result.tapes, Tape::ZX80O81P, TargetPlatform::ZX8081)											// P81
 
 	// PRG
 	if(extension == "prg") {
@@ -129,16 +134,16 @@ static Media GetMediaAndPlatforms(const std::string &file_name, TargetPlatform::
 	Format(	"rom",
 			result.cartridges,
 			Cartridge::BinaryDump,
-			TargetPlatform::AcornElectron | TargetPlatform::ColecoVision | TargetPlatform::MSX)				// ROM
-	Format("sg", result.cartridges, Cartridge::BinaryDump, TargetPlatform::Sega)							// SG
-	Format("sms", result.cartridges, Cartridge::BinaryDump, TargetPlatform::Sega)							// SMS
-	Format("ssd", result.disks, Disk::DiskImageHolder<Storage::Disk::SSD>, TargetPlatform::Acorn)			// SSD
-	Format("tap", result.tapes, Tape::CommodoreTAP, TargetPlatform::Commodore)								// TAP (Commodore)
-	Format("tap", result.tapes, Tape::OricTAP, TargetPlatform::Oric)										// TAP (Oric)
-	Format("tsx", result.tapes, Tape::TZX, TargetPlatform::MSX)												// TSX
-	Format("tzx", result.tapes, Tape::TZX, TargetPlatform::ZX8081)											// TZX
-	Format("uef", result.tapes, Tape::UEF, TargetPlatform::Acorn)											// UEF (tape)
-	Format("woz", result.disks, Disk::DiskImageHolder<Storage::Disk::WOZ>, TargetPlatform::DiskII)			// WOZ
+			TargetPlatform::AcornElectron | TargetPlatform::ColecoVision | TargetPlatform::MSX)					// ROM
+	Format("sg", result.cartridges, Cartridge::BinaryDump, TargetPlatform::Sega)								// SG
+	Format("sms", result.cartridges, Cartridge::BinaryDump, TargetPlatform::Sega)								// SMS
+	Format("ssd", result.disks, Disk::DiskImageHolder<Storage::Disk::SSD>, TargetPlatform::Acorn)				// SSD
+	Format("tap", result.tapes, Tape::CommodoreTAP, TargetPlatform::Commodore)									// TAP (Commodore)
+	Format("tap", result.tapes, Tape::OricTAP, TargetPlatform::Oric)											// TAP (Oric)
+	Format("tsx", result.tapes, Tape::TZX, TargetPlatform::MSX)													// TSX
+	Format("tzx", result.tapes, Tape::TZX, TargetPlatform::ZX8081)												// TZX
+	Format("uef", result.tapes, Tape::UEF, TargetPlatform::Acorn)												// UEF (tape)
+	Format("woz", result.disks, Disk::DiskImageHolder<Storage::Disk::WOZ>, TargetPlatform::DiskII)				// WOZ
 
 #undef Format
 #undef Insert
@@ -173,9 +178,10 @@ TargetList Analyser::Static::GetTargets(const std::string &file_name) {
 	if(potential_platforms & TargetPlatform::ColecoVision)	Append(Coleco);
 	if(potential_platforms & TargetPlatform::Commodore)		Append(Commodore);
 	if(potential_platforms & TargetPlatform::DiskII)		Append(DiskII);
-	if(potential_platforms & TargetPlatform::Sega)			Append(Sega);
+	if(potential_platforms & TargetPlatform::Macintosh)		Append(Macintosh);
 	if(potential_platforms & TargetPlatform::MSX)			Append(MSX);
 	if(potential_platforms & TargetPlatform::Oric)			Append(Oric);
+	if(potential_platforms & TargetPlatform::Sega)			Append(Sega);
 	if(potential_platforms & TargetPlatform::ZX8081)		Append(ZX8081);
 	#undef Append
 

ClockReceiver/ClockReceiver.hpp

@@ -9,6 +9,8 @@
 #ifndef ClockReceiver_hpp
 #define ClockReceiver_hpp
 
+#include "ForceInline.hpp"
+
 /*
 	Informal pattern for all classes that run from a clock cycle:
 
@@ -52,79 +54,92 @@
 */
 template <class T> class WrappedInt {
 	public:
-		constexpr WrappedInt(int l) : length_(l) {}
-		constexpr WrappedInt() : length_(0) {}
+		forceinline constexpr WrappedInt(int l) noexcept : length_(l) {}
+		forceinline constexpr WrappedInt() noexcept : length_(0) {}
 
-		T &operator =(const T &rhs) {
+		forceinline T &operator =(const T &rhs) {
 			length_ = rhs.length_;
 			return *this;
 		}
 
-		T &operator +=(const T &rhs) {
+		forceinline T &operator +=(const T &rhs) {
 			length_ += rhs.length_;
 			return *static_cast<T *>(this);
 		}
 
-		T &operator -=(const T &rhs) {
+		forceinline T &operator -=(const T &rhs) {
 			length_ -= rhs.length_;
 			return *static_cast<T *>(this);
 		}
 
-		T &operator ++() {
+		forceinline T &operator ++() {
 			++ length_;
 			return *static_cast<T *>(this);
 		}
 
-		T &operator ++(int) {
+		forceinline T &operator ++(int) {
 			length_ ++;
 			return *static_cast<T *>(this);
 		}
 
-		T &operator --() {
+		forceinline T &operator --() {
 			-- length_;
 			return *static_cast<T *>(this);
 		}
 
-		T &operator --(int) {
+		forceinline T &operator --(int) {
 			length_ --;
 			return *static_cast<T *>(this);
 		}
 
-		T &operator %=(const T &rhs) {
+		forceinline T &operator *=(const T &rhs) {
+			length_ *= rhs.length_;
+			return *static_cast<T *>(this);
+		}
+
+		forceinline T &operator /=(const T &rhs) {
+			length_ /= rhs.length_;
+			return *static_cast<T *>(this);
+		}
+
+		forceinline T &operator %=(const T &rhs) {
 			length_ %= rhs.length_;
 			return *static_cast<T *>(this);
 		}
 
-		T &operator &=(const T &rhs) {
+		forceinline T &operator &=(const T &rhs) {
 			length_ &= rhs.length_;
 			return *static_cast<T *>(this);
 		}
 
-		constexpr T operator +(const T &rhs) const			{	return T(length_ + rhs.length_);	}
-		constexpr T operator -(const T &rhs) const			{	return T(length_ - rhs.length_);	}
+		forceinline constexpr T operator +(const T &rhs) const			{	return T(length_ + rhs.length_);	}
+		forceinline constexpr T operator -(const T &rhs) const			{	return T(length_ - rhs.length_);	}
 
-		constexpr T operator %(const T &rhs) const			{	return T(length_ % rhs.length_);	}
-		constexpr T operator &(const T &rhs) const			{	return T(length_ & rhs.length_);	}
+		forceinline constexpr T operator *(const T &rhs) const			{	return T(length_ * rhs.length_);	}
+		forceinline constexpr T operator /(const T &rhs) const			{	return T(length_ / rhs.length_);	}
 
-		constexpr T operator -() const						{	return T(- length_);				}
+		forceinline constexpr T operator %(const T &rhs) const			{	return T(length_ % rhs.length_);	}
+		forceinline constexpr T operator &(const T &rhs) const			{	return T(length_ & rhs.length_);	}
 
-		constexpr bool operator <(const T &rhs) const		{	return length_ < rhs.length_;		}
-		constexpr bool operator >(const T &rhs) const		{	return length_ > rhs.length_;		}
-		constexpr bool operator <=(const T &rhs) const		{	return length_ <= rhs.length_;		}
-		constexpr bool operator >=(const T &rhs) const		{	return length_ >= rhs.length_;		}
-		constexpr bool operator ==(const T &rhs) const		{	return length_ == rhs.length_;		}
-		constexpr bool operator !=(const T &rhs) const		{	return length_ != rhs.length_;		}
+		forceinline constexpr T operator -() const						{	return T(- length_);				}
 
-		constexpr bool operator !() const					{	return !length_;					}
+		forceinline constexpr bool operator <(const T &rhs) const		{	return length_ < rhs.length_;		}
+		forceinline constexpr bool operator >(const T &rhs) const		{	return length_ > rhs.length_;		}
+		forceinline constexpr bool operator <=(const T &rhs) const		{	return length_ <= rhs.length_;		}
+		forceinline constexpr bool operator >=(const T &rhs) const		{	return length_ >= rhs.length_;		}
+		forceinline constexpr bool operator ==(const T &rhs) const		{	return length_ == rhs.length_;		}
+		forceinline constexpr bool operator !=(const T &rhs) const		{	return length_ != rhs.length_;		}
+
+		forceinline constexpr bool operator !() const					{	return !length_;					}
 		// bool operator () is not supported because it offers an implicit cast to int, which is prone silently to permit misuse
 
-		constexpr int as_int() const { return length_; }
+		forceinline constexpr int as_int() const { return length_; }
 
 		/*!
 			Severs from @c this the effect of dividing by @c divisor; @c this will end up with
 			the value of @c this modulo @c divisor and @c divided by @c divisor is returned.
 		*/
-		T divide(const T &divisor) {
+		forceinline T divide(const T &divisor) {
 			T result(length_ / divisor.length_);
 			length_ %= divisor.length_;
 			return result;
@@ -134,10 +149,12 @@ template <class T> class WrappedInt {
 			Flushes the value in @c this. The current value is returned, and the internal value
 			is reset to zero.
 		*/
-		T flush() {
-			T result(length_);
-			length_ = 0;
-			return result;
+		template <typename Result> Result flush() {
+			// Jiggery pokery here; switching to function overloading avoids
+			// the namespace-level requirement for template specialisation.
+			Result r;
+			static_cast<T *>(this)->fill(r);
+			return r;
 		}
 
 		// operator int() is deliberately not provided, to avoid accidental subtitution of
@@ -150,51 +167,59 @@ template <class T> class WrappedInt {
 /// Describes an integer number of whole cycles: pairs of clock signal transitions.
 class Cycles: public WrappedInt<Cycles> {
 	public:
-		constexpr Cycles(int l) : WrappedInt<Cycles>(l) {}
-		constexpr Cycles() : WrappedInt<Cycles>() {}
-		constexpr Cycles(const Cycles &cycles) : WrappedInt<Cycles>(cycles.length_) {}
+		forceinline constexpr Cycles(int l) noexcept : WrappedInt<Cycles>(l) {}
+		forceinline constexpr Cycles() noexcept : WrappedInt<Cycles>() {}
+		forceinline constexpr Cycles(const Cycles &cycles) noexcept : WrappedInt<Cycles>(cycles.length_) {}
+
+	private:
+		friend WrappedInt;
+		void fill(Cycles &result) {
+			result.length_ = length_;
+			length_ = 0;
+		}
 };
 
 /// Describes an integer number of half cycles: single clock signal transitions.
 class HalfCycles: public WrappedInt<HalfCycles> {
 	public:
-		constexpr HalfCycles(int l) : WrappedInt<HalfCycles>(l) {}
-		constexpr HalfCycles() : WrappedInt<HalfCycles>() {}
+		forceinline constexpr HalfCycles(int l) noexcept : WrappedInt<HalfCycles>(l) {}
+		forceinline constexpr HalfCycles() noexcept : WrappedInt<HalfCycles>() {}
 
-		constexpr HalfCycles(const Cycles cycles) : WrappedInt<HalfCycles>(cycles.as_int() * 2) {}
-		constexpr HalfCycles(const HalfCycles &half_cycles) : WrappedInt<HalfCycles>(half_cycles.length_) {}
+		forceinline constexpr HalfCycles(const Cycles &cycles) noexcept : WrappedInt<HalfCycles>(cycles.as_int() * 2) {}
+		forceinline constexpr HalfCycles(const HalfCycles &half_cycles) noexcept : WrappedInt<HalfCycles>(half_cycles.length_) {}
 
 		/// @returns The number of whole cycles completely covered by this span of half cycles.
-		constexpr Cycles cycles() const {
+		forceinline constexpr Cycles cycles() const {
 			return Cycles(length_ >> 1);
 		}
 
-		/// Flushes the whole cycles in @c this, subtracting that many from the total stored here.
-		Cycles flush_cycles() {
-			Cycles result(length_ >> 1);
-			length_ &= 1;
-			return result;
-		}
-
-		/// Flushes the half cycles in @c this, returning the number stored and setting this total to zero.
-		HalfCycles flush() {
-			HalfCycles result(length_);
-			length_ = 0;
-			return result;
-		}
-
 		/*!
 			Severs from @c this the effect of dividing by @c divisor; @c this will end up with
 			the value of @c this modulo @c divisor and @c divided by @c divisor is returned.
 		*/
-		Cycles divide_cycles(const Cycles &divisor) {
-			HalfCycles half_divisor = HalfCycles(divisor);
-			Cycles result(length_ / half_divisor.length_);
+		forceinline Cycles divide_cycles(const Cycles &divisor) {
+			const HalfCycles half_divisor = HalfCycles(divisor);
+			const Cycles result(length_ / half_divisor.length_);
 			length_ %= half_divisor.length_;
 			return result;
 		}
+
+	private:
+		friend WrappedInt;
+		void fill(Cycles &result) {
+			result = Cycles(length_ >> 1);
+			length_ &= 1;
+		}
+
+		void fill(HalfCycles &result) {
+			result.length_ = length_;
+			length_ = 0;
+		}
 };
 
+// Create a specialisation of WrappedInt::flush for converting HalfCycles to Cycles
+// without losing the fractional part.
+
 /*!
 	If a component implements only run_for(Cycles), an owner can wrap it in HalfClockReceiver
 	automatically to gain run_for(HalfCycles).
@@ -203,9 +228,9 @@ template <class T> class HalfClockReceiver: public T {
 	public:
 		using T::T;
 
-		inline void run_for(const HalfCycles half_cycles) {
+		forceinline void run_for(const HalfCycles half_cycles) {
 			half_cycles_ += half_cycles;
-			T::run_for(half_cycles_.flush_cycles());
+			T::run_for(half_cycles_.flush<Cycles>());
 		}
 
 	private:

ClockReceiver/DeferredQueue.hpp

@@ -1,26 +1,26 @@
 //
-//  ClockDeferrer.hpp
+//  DeferredQueue.hpp
 //  Clock Signal
 //
 //  Created by Thomas Harte on 23/08/2018.
 //  Copyright © 2018 Thomas Harte. All rights reserved.
 //
 
-#ifndef ClockDeferrer_h
-#define ClockDeferrer_h
+#ifndef DeferredQueue_h
+#define DeferredQueue_h
 
 #include <functional>
 #include <vector>
 
 /*!
-	A ClockDeferrer maintains a list of ordered actions and the times at which
+	A DeferredQueue maintains a list of ordered actions and the times at which
 	they should happen, and divides a total execution period up into the portions
 	that occur between those actions, triggering each action when it is reached.
 */
-template <typename TimeUnit> class ClockDeferrer {
+template <typename TimeUnit> class DeferredQueue {
 	public:
-		/// Constructs a ClockDeferrer that will call target(period) in between deferred actions.
-		ClockDeferrer(std::function<void(TimeUnit)> &&target) : target_(std::move(target)) {}
+		/// Constructs a DeferredQueue that will call target(period) in between deferred actions.
+		DeferredQueue(std::function<void(TimeUnit)> &&target) : target_(std::move(target)) {}
 
 		/*!
 			Schedules @c action to occur in @c delay units of time.
@@ -79,4 +79,4 @@ template <typename TimeUnit> class ClockDeferrer {
 		std::vector<DeferredAction> pending_actions_;
 };
 
-#endif /* ClockDeferrer_h */
+#endif /* DeferredQueue_h */

ClockReceiver/JustInTime.hpp

@@ -0,0 +1,110 @@
+//
+//  JustInTime.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 28/07/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef JustInTime_h
+#define JustInTime_h
+
+#include "../Concurrency/AsyncTaskQueue.hpp"
+
+/*!
+	A JustInTimeActor holds (i) an embedded object with a run_for method; and (ii) an amount
+	of time since run_for was last called.
+
+	Time can be added using the += operator. The -> operator can be used to access the
+	embedded object. All time accumulated will be pushed to object before the pointer is returned.
+
+	Machines that accumulate HalfCycle time but supply to a Cycle-counted device may supply a
+	separate @c TargetTimeScale at template declaration.
+*/
+template <class T, class LocalTimeScale, class TargetTimeScale = LocalTimeScale> class JustInTimeActor {
+	public:
+		/// Constructs a new JustInTimeActor using the same construction arguments as the included object.
+		template<typename... Args> JustInTimeActor(Args&&... args) : object_(std::forward<Args>(args)...) {}
+
+		/// Adds time to the actor.
+		inline void operator += (const LocalTimeScale &rhs) {
+			time_since_update_ += rhs;
+			is_flushed_ = false;
+		}
+
+		/// Flushes all accumulated time and returns a pointer to the included object.
+		inline T *operator->() {
+			flush();
+			return &object_;
+		}
+
+		/// Returns a pointer to the included object without flushing time.
+		inline T *last_valid() {
+			return &object_;
+		}
+
+		/// Flushes all accumulated time.
+		inline void flush() {
+			if(!is_flushed_) object_.run_for(time_since_update_.template flush<TargetTimeScale>());
+			is_flushed_ = true;
+		}
+
+	private:
+		T object_;
+		LocalTimeScale time_since_update_;
+		bool is_flushed_ = true;
+};
+
+/*!
+	A AsyncJustInTimeActor acts like a JustInTimeActor but additionally contains an AsyncTaskQueue.
+	Any time the amount of accumulated time crosses a threshold provided at construction time,
+	the object will be updated on the AsyncTaskQueue.
+*/
+template <class T, class LocalTimeScale, class TargetTimeScale = LocalTimeScale> class AsyncJustInTimeActor {
+	public:
+		/// Constructs a new AsyncJustInTimeActor using the same construction arguments as the included object.
+		template<typename... Args> AsyncJustInTimeActor(TargetTimeScale threshold, Args&&... args) :
+			object_(std::forward<Args>(args)...),
+		 	threshold_(threshold) {}
+
+		/// Adds time to the actor.
+		inline void operator += (const LocalTimeScale &rhs) {
+			time_since_update_ += rhs;
+			if(time_since_update_ >= threshold_) {
+				time_since_update_ -= threshold_;
+				task_queue_.enqueue([this] () {
+					object_.run_for(threshold_);
+				});
+			}
+			is_flushed_ = false;
+		}
+
+		/// Flushes all accumulated time and returns a pointer to the included object.
+		inline T *operator->() {
+			flush();
+			return &object_;
+		}
+
+		/// Returns a pointer to the included object without flushing time.
+		inline T *last_valid() {
+			return &object_;
+		}
+
+		/// Flushes all accumulated time.
+		inline void flush() {
+			if(!is_flushed_) {
+				task_queue_.flush();
+				object_.run_for(time_since_update_.template flush<TargetTimeScale>());
+				is_flushed_ = true;
+			}
+		}
+
+	private:
+		T object_;
+		LocalTimeScale time_since_update_;
+		TargetTimeScale threshold_;
+		bool is_flushed_ = true;
+		Concurrency::AsyncTaskQueue task_queue_;
+};
+
+#endif /* JustInTime_h */

Components/6522/6522.hpp

@@ -47,6 +47,12 @@ class PortHandler {
 
 		/// Sets the current logical value of the interrupt line.
 		void set_interrupt_status(bool status)									{}
+
+		/// Provides a measure of time elapsed between other calls.
+		void run_for(HalfCycles duration)										{}
+
+		/// Receives passed-on flush() calls from the 6522.
+		void flush()															{}
 };
 
 /*!
@@ -71,26 +77,6 @@ class IRQDelegatePortHandler: public PortHandler {
 		Delegate *delegate_ = nullptr;
 };
 
-class MOS6522Base: public MOS6522Storage {
-	public:
-		/// Sets the input value of line @c line on port @c port.
-		void set_control_line_input(Port port, Line line, bool value);
-
-		/// Runs for a specified number of half cycles.
-		void run_for(const HalfCycles half_cycles);
-
-		/// Runs for a specified number of cycles.
-		void run_for(const Cycles cycles);
-
-		/// @returns @c true if the IRQ line is currently active; @c false otherwise.
-		bool get_interrupt_line();
-
-	private:
-		inline void do_phase1();
-		inline void do_phase2();
-		virtual void reevaluate_interrupts() = 0;
-};
-
 /*!
 	Implements a template for emulation of the MOS 6522 Versatile Interface Adaptor ('VIA').
 
@@ -102,7 +88,7 @@ class MOS6522Base: public MOS6522Storage {
 	Consumers should derive their own curiously-recurring-template-pattern subclass,
 	implementing bus communications as required.
 */
-template <class T> class MOS6522: public MOS6522Base {
+template <class T> class MOS6522: public MOS6522Storage {
 	public:
 		MOS6522(T &bus_handler) noexcept : bus_handler_(bus_handler) {}
 		MOS6522(const MOS6522 &) = delete;
@@ -116,11 +102,39 @@ template <class T> class MOS6522: public MOS6522Base {
 		/*! @returns the bus handler. */
 		T &bus_handler();
 
+		/// Sets the input value of line @c line on port @c port.
+		void set_control_line_input(Port port, Line line, bool value);
+
+		/// Runs for a specified number of half cycles.
+		void run_for(const HalfCycles half_cycles);
+
+		/// Runs for a specified number of cycles.
+		void run_for(const Cycles cycles);
+
+		/// @returns @c true if the IRQ line is currently active; @c false otherwise.
+		bool get_interrupt_line();
+
+		/// Updates the port handler to the current time and then requests that it flush.
+		void flush();
+
 	private:
+		void do_phase1();
+		void do_phase2();
+		void shift_in();
+		void shift_out();
+
 		T &bus_handler_;
+		HalfCycles time_since_bus_handler_call_;
+
+		void access(int address);
 
 		uint8_t get_port_input(Port port, uint8_t output_mask, uint8_t output);
 		inline void reevaluate_interrupts();
+
+		/// Sets the current intended output value for the port and line;
+		/// if this affects the visible output, it will be passed to the handler.
+		void set_control_line_output(Port port, Line line, LineState value);
+		void evaluate_cb2_output();
 };
 
 }

Components/6522/Implementation/6522Base.cpp

@@ -1,116 +0,0 @@
-//
-//  6522Base.cpp
-//  Clock Signal
-//
-//  Created by Thomas Harte on 04/09/2017.
-//  Copyright 2017 Thomas Harte. All rights reserved.
-//
-
-#include "../6522.hpp"
-
-using namespace MOS::MOS6522;
-
-void MOS6522Base::set_control_line_input(Port port, Line line, bool value) {
-	switch(line) {
-		case Line::One:
-			if(	value != control_inputs_[port].line_one &&
-				value == !!(registers_.peripheral_control & (port ? 0x10 : 0x01))
-			) {
-				registers_.interrupt_flags |= port ? InterruptFlag::CB1ActiveEdge : InterruptFlag::CA1ActiveEdge;
-				reevaluate_interrupts();
-			}
-			control_inputs_[port].line_one = value;
-		break;
-
-		case Line::Two:
-			// TODO: output modes, but probably elsewhere?
-			if(	value != control_inputs_[port].line_two &&							// i.e. value has changed ...
-				!(registers_.peripheral_control & (port ? 0x80 : 0x08)) &&			// ... and line is input ...
-				value == !!(registers_.peripheral_control & (port ? 0x40 : 0x04))	// ... and it's either high or low, as required
-			) {
-				registers_.interrupt_flags |= port ? InterruptFlag::CB2ActiveEdge : InterruptFlag::CA2ActiveEdge;
-				reevaluate_interrupts();
-			}
-			control_inputs_[port].line_two = value;
-		break;
-	}
-}
-
-void MOS6522Base::do_phase2() {
-	registers_.last_timer[0] = registers_.timer[0];
-	registers_.last_timer[1] = registers_.timer[1];
-
-	if(registers_.timer_needs_reload) {
-		registers_.timer_needs_reload = false;
-		registers_.timer[0] = registers_.timer_latch[0];
-	} else {
-		registers_.timer[0] --;
-	}
-
-	registers_.timer[1] --;
-	if(registers_.next_timer[0] >= 0) {
-		registers_.timer[0] = static_cast<uint16_t>(registers_.next_timer[0]);
-		registers_.next_timer[0] = -1;
-	}
-	if(registers_.next_timer[1] >= 0) {
-		registers_.timer[1] = static_cast<uint16_t>(registers_.next_timer[1]);
-		registers_.next_timer[1] = -1;
-	}
-}
-
-void MOS6522Base::do_phase1() {
-	// IRQ is raised on the half cycle after overflow
-	if((registers_.timer[1] == 0xffff) && !registers_.last_timer[1] && timer_is_running_[1]) {
-		timer_is_running_[1] = false;
-		registers_.interrupt_flags |= InterruptFlag::Timer2;
-		reevaluate_interrupts();
-	}
-
-	if((registers_.timer[0] == 0xffff) && !registers_.last_timer[0] && timer_is_running_[0]) {
-		registers_.interrupt_flags |= InterruptFlag::Timer1;
-		reevaluate_interrupts();
-
-		if(registers_.auxiliary_control&0x40)
-			registers_.timer_needs_reload = true;
-		else
-			timer_is_running_[0] = false;
-	}
-}
-
-/*! Runs for a specified number of half cycles. */
-void MOS6522Base::run_for(const HalfCycles half_cycles) {
-	int number_of_half_cycles = half_cycles.as_int();
-
-	if(is_phase2_) {
-		do_phase2();
-		number_of_half_cycles--;
-	}
-
-	while(number_of_half_cycles >= 2) {
-		do_phase1();
-		do_phase2();
-		number_of_half_cycles -= 2;
-	}
-
-	if(number_of_half_cycles) {
-		do_phase1();
-		is_phase2_ = true;
-	} else {
-		is_phase2_ = false;
-	}
-}
-
-/*! Runs for a specified number of cycles. */
-void MOS6522Base::run_for(const Cycles cycles) {
-	int number_of_cycles = cycles.as_int();
-	while(number_of_cycles--) {
-		do_phase1();
-		do_phase2();
-	}
-}
-
-/*! @returns @c true if the IRQ line is currently active; @c false otherwise. */
-bool MOS6522Base::get_interrupt_line() {
-	uint8_t interrupt_status = registers_.interrupt_flags & registers_.interrupt_enable & 0x7f;
-	return !!interrupt_status;
-}

Components/6522/Implementation/6522Implementation.hpp

@@ -11,29 +11,58 @@
 namespace MOS {
 namespace MOS6522 {
 
-template <typename T> void MOS6522<T>::set_register(int address, uint8_t value) {
-	address &= 0xf;
+template <typename T> void MOS6522<T>::access(int address) {
 	switch(address) {
 		case 0x0:
+			// In both handshake and pulse modes, CB2 goes low on any read or write of Port B.
+			if(handshake_modes_[1] != HandshakeMode::None) {
+				set_control_line_output(Port::B, Line::Two, LineState::Off);
+			}
+		break;
+
+		case 0xf:
+		case 0x1:
+			// In both handshake and pulse modes, CA2 goes low on any read or write of Port A.
+			if(handshake_modes_[0] != HandshakeMode::None) {
+				set_control_line_output(Port::A, Line::Two, LineState::Off);
+			}
+		break;
+	}
+}
+
+template <typename T> void MOS6522<T>::set_register(int address, uint8_t value) {
+	address &= 0xf;
+	access(address);
+	switch(address) {
+		case 0x0:	// Write Port B.
+			// Store locally and communicate outwards.
 			registers_.output[1] = value;
-			bus_handler_.set_port_output(Port::B, value, registers_.data_direction[1]);	// TODO: handshake
+
+			bus_handler_.run_for(time_since_bus_handler_call_.flush<HalfCycles>());
+			bus_handler_.set_port_output(Port::B, value, registers_.data_direction[1]);
 
 			registers_.interrupt_flags &= ~(InterruptFlag::CB1ActiveEdge | ((registers_.peripheral_control&0x20) ? 0 : InterruptFlag::CB2ActiveEdge));
 			reevaluate_interrupts();
 		break;
 		case 0xf:
-		case 0x1:
+		case 0x1:	// Write Port A.
 			registers_.output[0] = value;
-			bus_handler_.set_port_output(Port::A, value, registers_.data_direction[0]);	// TODO: handshake
+
+			bus_handler_.run_for(time_since_bus_handler_call_.flush<HalfCycles>());
+			bus_handler_.set_port_output(Port::A, value, registers_.data_direction[0]);
+
+			if(handshake_modes_[1] != HandshakeMode::None) {
+				set_control_line_output(Port::A, Line::Two, LineState::Off);
+			}
 
 			registers_.interrupt_flags &= ~(InterruptFlag::CA1ActiveEdge | ((registers_.peripheral_control&0x02) ? 0 : InterruptFlag::CB2ActiveEdge));
 			reevaluate_interrupts();
 		break;
 
-		case 0x2:
+		case 0x2:	// Port B direction.
 			registers_.data_direction[1] = value;
 		break;
-		case 0x3:
+		case 0x3:	// Port A direction.
 			registers_.data_direction[0] = value;
 		break;
 
@@ -59,31 +88,57 @@ template <typename T> void MOS6522<T>::set_register(int address, uint8_t value)
 		break;
 
 		// Shift
-		case 0xa:	registers_.shift = value;				break;
+		case 0xa:
+			registers_.shift = value;
+			shift_bits_remaining_ = 8;
+			registers_.interrupt_flags &= ~InterruptFlag::ShiftRegister;
+			reevaluate_interrupts();
+		break;
 
 		// Control
 		case 0xb:
 			registers_.auxiliary_control = value;
+			evaluate_cb2_output();
 		break;
-		case 0xc:
+		case 0xc: {
+//			const auto old_peripheral_control = registers_.peripheral_control;
 			registers_.peripheral_control = value;
 
-			// TODO: simplify below; trying to avoid improper logging of unimplemented warnings in input mode
-			if(value & 0x08) {
-				switch(value & 0x0e) {
-					default: 	LOG("Unimplemented control line mode " << int((value >> 1)&7));		break;
-					case 0x0c:	bus_handler_.set_control_line_output(Port::A, Line::Two, false);	break;
-					case 0x0e:	bus_handler_.set_control_line_output(Port::A, Line::Two, true);		break;
+			int shift = 0;
+			for(int port = 0; port < 2; ++port) {
+				handshake_modes_[port] = HandshakeMode::None;
+				switch((value >> shift) & 0x0e) {
+					default: break;
+
+					case 0x00:	// Negative interrupt input; set Cx2 interrupt on negative Cx2 transition, clear on access to Port x register.
+					case 0x02:	// Independent negative interrupt input; set Cx2 interrupt on negative transition, don't clear automatically.
+					case 0x04:	// Positive interrupt input; set Cx2 interrupt on positive Cx2 transition, clear on access to Port x register.
+					case 0x06:	// Independent positive interrupt input; set Cx2 interrupt on positive transition, don't clear automatically.
+						set_control_line_output(Port(port), Line::Two, LineState::Input);
+					break;
+
+					case 0x08:	// Handshake: set Cx2 to low on any read or write of Port x; set to high on an active transition of Cx1.
+						handshake_modes_[port] = HandshakeMode::Handshake;
+						set_control_line_output(Port(port), Line::Two, LineState::Off);	// At a guess.
+					break;
+
+					case 0x0a:	// Pulse output: Cx2 is low for one cycle following a read or write of Port x.
+						handshake_modes_[port] = HandshakeMode::Pulse;
+						set_control_line_output(Port(port), Line::Two, LineState::On);
+					break;
+
+					case 0x0c:	// Manual output: Cx2 low.
+						set_control_line_output(Port(port), Line::Two, LineState::Off);
+					break;
+
+					case 0x0e:	// Manual output: Cx2 high.
+						set_control_line_output(Port(port), Line::Two, LineState::On);
+					break;
 				}
+
+				shift += 4;
 			}
-			if(value & 0x80) {
-				switch(value & 0xe0) {
-					default: 	LOG("Unimplemented control line mode " << int((value >> 5)&7));		break;
-					case 0xc0:	bus_handler_.set_control_line_output(Port::B, Line::Two, false);	break;
-					case 0xe0:	bus_handler_.set_control_line_output(Port::B, Line::Two, true);		break;
-				}
-			}
-		break;
+		} break;
 
 		// Interrupt control
 		case 0xd:
@@ -102,12 +157,13 @@ template <typename T> void MOS6522<T>::set_register(int address, uint8_t value)
 
 template <typename T> uint8_t MOS6522<T>::get_register(int address) {
 	address &= 0xf;
+	access(address);
 	switch(address) {
 		case 0x0:
 			registers_.interrupt_flags &= ~(InterruptFlag::CB1ActiveEdge | InterruptFlag::CB2ActiveEdge);
 			reevaluate_interrupts();
 		return get_port_input(Port::B, registers_.data_direction[1], registers_.output[1]);
-		case 0xf:	// TODO: handshake, latching
+		case 0xf:
 		case 0x1:
 			registers_.interrupt_flags &= ~(InterruptFlag::CA1ActiveEdge | InterruptFlag::CA2ActiveEdge);
 			reevaluate_interrupts();
@@ -132,7 +188,11 @@ template <typename T> uint8_t MOS6522<T>::get_register(int address) {
 		return registers_.timer[1] & 0x00ff;
 		case 0x9:	return registers_.timer[1] >> 8;
 
-		case 0xa:	return registers_.shift;
+		case 0xa:
+			shift_bits_remaining_ = 8;
+			registers_.interrupt_flags &= ~InterruptFlag::ShiftRegister;
+			reevaluate_interrupts();
+		return registers_.shift;
 
 		case 0xb:	return registers_.auxiliary_control;
 		case 0xc:	return registers_.peripheral_control;
@@ -145,7 +205,8 @@ template <typename T> uint8_t MOS6522<T>::get_register(int address) {
 }
 
 template <typename T> uint8_t MOS6522<T>::get_port_input(Port port, uint8_t output_mask, uint8_t output) {
-	uint8_t input = bus_handler_.get_port_input(port);
+	bus_handler_.run_for(time_since_bus_handler_call_.flush<HalfCycles>());
+	const uint8_t input = bus_handler_.get_port_input(port);
 	return (input & ~output_mask) | (output & output_mask);
 }
 
@@ -158,9 +219,238 @@ template <typename T> void MOS6522<T>::reevaluate_interrupts() {
 	bool new_interrupt_status = get_interrupt_line();
 	if(new_interrupt_status != last_posted_interrupt_status_) {
 		last_posted_interrupt_status_ = new_interrupt_status;
+
+		bus_handler_.run_for(time_since_bus_handler_call_.flush<HalfCycles>());
 		bus_handler_.set_interrupt_status(new_interrupt_status);
 	}
 }
 
+template <typename T> void MOS6522<T>::set_control_line_input(Port port, Line line, bool value) {
+	switch(line) {
+		case Line::One:
+			if(value != control_inputs_[port].lines[line]) {
+				// In handshake mode, any transition on C[A/B]1 sets output high on C[A/B]2.
+				if(handshake_modes_[port] == HandshakeMode::Handshake) {
+					set_control_line_output(port, Line::Two, LineState::On);
+				}
+
+				// Set the proper transition interrupt bit if enabled.
+				if(value == !!(registers_.peripheral_control & (port ? 0x10 : 0x01))) {
+					registers_.interrupt_flags |= port ? InterruptFlag::CB1ActiveEdge : InterruptFlag::CA1ActiveEdge;
+					reevaluate_interrupts();
+				}
+
+				// If this is a transition on CB1, consider updating the shift register.
+				// TODO: and at least one full clock since the shift register was written?
+				if(port == Port::B) {
+					switch(shift_mode()) {
+						default: 													break;
+						case ShiftMode::InUnderCB1:		if(value)	shift_in();		break;	// Shifts in are captured on a low-to-high transition.
+						case ShiftMode::OutUnderCB1:	if(!value)	shift_out();	break;	// Shifts out are updated on a high-to-low transition.
+					}
+				}
+			}
+			control_inputs_[port].lines[line] = value;
+		break;
+
+		case Line::Two:
+			if(	value != control_inputs_[port].lines[line] &&						// i.e. value has changed ...
+				!(registers_.peripheral_control & (port ? 0x80 : 0x08)) &&			// ... and line is input ...
+				value == !!(registers_.peripheral_control & (port ? 0x40 : 0x04))	// ... and it's either high or low, as required
+			) {
+				registers_.interrupt_flags |= port ? InterruptFlag::CB2ActiveEdge : InterruptFlag::CA2ActiveEdge;
+				reevaluate_interrupts();
+			}
+			control_inputs_[port].lines[line] = value;
+		break;
+	}
+}
+
+template <typename T> void MOS6522<T>::do_phase2() {
+	++ time_since_bus_handler_call_;
+
+	registers_.last_timer[0] = registers_.timer[0];
+	registers_.last_timer[1] = registers_.timer[1];
+
+	if(registers_.timer_needs_reload) {
+		registers_.timer_needs_reload = false;
+		registers_.timer[0] = registers_.timer_latch[0];
+	} else {
+		registers_.timer[0] --;
+	}
+
+	registers_.timer[1] --;
+	if(registers_.next_timer[0] >= 0) {
+		registers_.timer[0] = static_cast<uint16_t>(registers_.next_timer[0]);
+		registers_.next_timer[0] = -1;
+	}
+	if(registers_.next_timer[1] >= 0) {
+		registers_.timer[1] = static_cast<uint16_t>(registers_.next_timer[1]);
+		registers_.next_timer[1] = -1;
+	}
+
+	// In pulse modes, CA2 and CB2 go high again on the next clock edge.
+	if(handshake_modes_[1] == HandshakeMode::Pulse) {
+		set_control_line_output(Port::B, Line::Two, LineState::On);
+	}
+	if(handshake_modes_[0] == HandshakeMode::Pulse) {
+		set_control_line_output(Port::A, Line::Two, LineState::On);
+	}
+
+	// If the shift register is shifting according to the input clock, do a shift.
+	switch(shift_mode()) {
+		default: 											break;
+		case ShiftMode::InUnderPhase2:		shift_in();		break;
+		case ShiftMode::OutUnderPhase2:		shift_out();	break;
+	}
+}
+
+template <typename T> void MOS6522<T>::do_phase1() {
+	++ time_since_bus_handler_call_;
+
+	// IRQ is raised on the half cycle after overflow
+	if((registers_.timer[1] == 0xffff) && !registers_.last_timer[1] && timer_is_running_[1]) {
+		timer_is_running_[1] = false;
+
+		// If the shift register is shifting according to this timer, do a shift.
+		// TODO: "shift register is driven by only the low order 8 bits of timer 2"?
+		switch(shift_mode()) {
+			default: 												break;
+			case ShiftMode::InUnderT2:				shift_in();		break;
+			case ShiftMode::OutUnderT2FreeRunning: 	shift_out();	break;
+			case ShiftMode::OutUnderT2:				shift_out();	break;	// TODO: present a clock on CB1.
+		}
+
+		registers_.interrupt_flags |= InterruptFlag::Timer2;
+		reevaluate_interrupts();
+	}
+
+	if((registers_.timer[0] == 0xffff) && !registers_.last_timer[0] && timer_is_running_[0]) {
+		registers_.interrupt_flags |= InterruptFlag::Timer1;
+		reevaluate_interrupts();
+
+		// Determine whether to reload.
+		if(registers_.auxiliary_control&0x40)
+			registers_.timer_needs_reload = true;
+		else
+			timer_is_running_[0] = false;
+
+		// Determine whether to toggle PB7.
+		if(registers_.auxiliary_control&0x80) {
+			registers_.output[1] ^= 0x80;
+			bus_handler_.run_for(time_since_bus_handler_call_.flush<HalfCycles>());
+			bus_handler_.set_port_output(Port::B, registers_.output[1], registers_.data_direction[1]);
+		}
+	}
+}
+
+/*! Runs for a specified number of half cycles. */
+template <typename T> void MOS6522<T>::run_for(const HalfCycles half_cycles) {
+	int number_of_half_cycles = half_cycles.as_int();
+	if(!number_of_half_cycles) return;
+
+	if(is_phase2_) {
+		do_phase2();
+		number_of_half_cycles--;
+	}
+
+	while(number_of_half_cycles >= 2) {
+		do_phase1();
+		do_phase2();
+		number_of_half_cycles -= 2;
+	}
+
+	if(number_of_half_cycles) {
+		do_phase1();
+		is_phase2_ = true;
+	} else {
+		is_phase2_ = false;
+	}
+}
+
+template <typename T> void MOS6522<T>::flush() {
+	bus_handler_.run_for(time_since_bus_handler_call_.flush<HalfCycles>());
+	bus_handler_.flush();
+}
+
+/*! Runs for a specified number of cycles. */
+template <typename T> void MOS6522<T>::run_for(const Cycles cycles) {
+	int number_of_cycles = cycles.as_int();
+	while(number_of_cycles--) {
+		do_phase1();
+		do_phase2();
+	}
+}
+
+/*! @returns @c true if the IRQ line is currently active; @c false otherwise. */
+template <typename T> bool MOS6522<T>::get_interrupt_line() {
+	uint8_t interrupt_status = registers_.interrupt_flags & registers_.interrupt_enable & 0x7f;
+	return !!interrupt_status;
+}
+
+template <typename T> void MOS6522<T>::evaluate_cb2_output() {
+	// CB2 is a special case, being both the line the shift register can output to,
+	// and one that can be used as an input or handshaking output according to the
+	// peripheral control register.
+
+	// My guess: other CB2 functions work only if the shift register is disabled (?).
+	if(shift_mode() != ShiftMode::Disabled) {
+		// Shift register is enabled, one way or the other; but announce only output.
+		if(is_shifting_out()) {
+			// Output mode; set the level according to the current top of the shift register.
+			bus_handler_.set_control_line_output(Port::B, Line::Two, !!(registers_.shift & 0x80));
+		} else {
+			// Input mode.
+			bus_handler_.set_control_line_output(Port::B, Line::Two, true);
+		}
+	} else {
+		// Shift register is disabled.
+		bus_handler_.set_control_line_output(Port::B, Line::Two, control_outputs_[1].lines[1] != LineState::Off);
+	}
+}
+
+template <typename T> void MOS6522<T>::set_control_line_output(Port port, Line line, LineState value) {
+	if(port == Port::B && line == Line::Two) {
+		control_outputs_[port].lines[line] = value;
+		evaluate_cb2_output();
+	} else {
+		// Do nothing if unchanged.
+		if(value == control_outputs_[port].lines[line]) {
+			return;
+		}
+
+		control_outputs_[port].lines[line] = value;
+
+		if(value != LineState::Input) {
+			bus_handler_.run_for(time_since_bus_handler_call_.flush<HalfCycles>());
+			bus_handler_.set_control_line_output(port, line, value != LineState::Off);
+		}
+	}
+}
+
+template <typename T> void MOS6522<T>::shift_in() {
+	registers_.shift = uint8_t((registers_.shift << 1) | (control_inputs_[1].lines[1] ? 1 : 0));
+	--shift_bits_remaining_;
+	if(!shift_bits_remaining_) {
+		registers_.interrupt_flags |= InterruptFlag::ShiftRegister;
+		reevaluate_interrupts();
+	}
+}
+
+template <typename T> void MOS6522<T>::shift_out() {
+	// When shifting out, the shift register rotates rather than strictly shifts.
+	// TODO: is that true for all modes?
+	if(shift_mode() == ShiftMode::OutUnderT2FreeRunning || shift_bits_remaining_) {
+		registers_.shift = uint8_t((registers_.shift << 1) | (registers_.shift >> 7));
+		evaluate_cb2_output();
+
+		--shift_bits_remaining_;
+		if(!shift_bits_remaining_) {
+			registers_.interrupt_flags |= InterruptFlag::ShiftRegister;
+			reevaluate_interrupts();
+		}
+	}
+}
+
 }
 }

Components/6522/Implementation/6522Storage.hpp

@@ -21,7 +21,7 @@ class MOS6522Storage {
 
 		// The registers
 		struct Registers {
-			// "A  low  reset  (RES)  input  clears  all  R6522  internal registers to logic 0"
+			// "A low reset (RES) input clears all R6522 internal registers to logic 0"
 			uint8_t output[2] = {0, 0};
 			uint8_t input[2] = {0, 0};
 			uint8_t data_direction[2] = {0, 0};
@@ -37,14 +37,27 @@ class MOS6522Storage {
 			bool timer_needs_reload = false;
 		} registers_;
 
-		// control state
+		// Control state.
 		struct {
-			bool line_one = false;
-			bool line_two = false;
+			bool lines[2] = {false, false};
 		} control_inputs_[2];
 
+		enum class LineState {
+			On, Off, Input
+		};
+		struct {
+			LineState lines[2] = {LineState::Input, LineState::Input};
+		} control_outputs_[2];
+
+		enum class HandshakeMode {
+			None,
+			Handshake,
+			Pulse
+		} handshake_modes_[2] = { HandshakeMode::None, HandshakeMode::None };
+
 		bool timer_is_running_[2] = {false, false};
 		bool last_posted_interrupt_status_ = false;
+		int shift_bits_remaining_ = 8;
 
 		enum InterruptFlag: uint8_t {
 			CA2ActiveEdge	= 1 << 0,
@@ -55,6 +68,23 @@ class MOS6522Storage {
 			Timer2			= 1 << 5,
 			Timer1			= 1 << 6,
 		};
+
+		enum class ShiftMode {
+			Disabled = 0,
+			InUnderT2 = 1,
+			InUnderPhase2 = 2,
+			InUnderCB1 = 3,
+			OutUnderT2FreeRunning = 4,
+			OutUnderT2 = 5,
+			OutUnderPhase2 = 6,
+			OutUnderCB1 = 7
+		};
+		ShiftMode shift_mode() const {
+			return ShiftMode((registers_.auxiliary_control >> 2) & 7);
+		}
+		bool is_shifting_out() const {
+			return registers_.auxiliary_control & 0x10;
+		}
 };
 
 }

Components/8530/z8530.cpp

@@ -0,0 +1,268 @@
+//
+//  8530.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "z8530.hpp"
+
+#include "../../Outputs/Log.hpp"
+
+using namespace Zilog::SCC;
+
+void z8530::reset() {
+	// TODO.
+}
+
+bool z8530::get_interrupt_line() {
+	return
+		(master_interrupt_control_ & 0x8) &&
+		(
+			channels_[0].get_interrupt_line() ||
+			channels_[1].get_interrupt_line()
+		);
+}
+
+std::uint8_t z8530::read(int address) {
+	if(address & 2) {
+		// Read data register for channel
+		return 0x00;
+	} else {
+		// Read control register for channel.
+		uint8_t result = 0;
+
+		switch(pointer_) {
+			default:
+				result = channels_[address & 1].read(address & 2, pointer_);
+			break;
+
+			case 2:		// Handled non-symmetrically between channels.
+				if(address & 1) {
+					LOG("[SCC] Unimplemented: register 2 status bits");
+				} else {
+					result = interrupt_vector_;
+
+					// Modify the vector if permitted.
+//					if(master_interrupt_control_ & 1) {
+						for(int port = 0; port < 2; ++port) {
+							// TODO: the logic below assumes that DCD is the only implemented interrupt. Fix.
+							if(channels_[port].get_interrupt_line()) {
+								const uint8_t shift = 1 + 3*((master_interrupt_control_ & 0x10) >> 4);
+								const uint8_t mask = uint8_t(~(7 << shift));
+								result = uint8_t(
+									(result & mask) |
+									((1 | ((port == 1) ? 4 : 0)) << shift)
+								);
+								break;
+							}
+						}
+//					}
+				}
+			break;
+		}
+
+		pointer_ = 0;
+		update_delegate();
+		return result;
+	}
+
+	return 0x00;
+}
+
+void z8530::write(int address, std::uint8_t value) {
+	if(address & 2) {
+		// Write data register for channel.
+	} else {
+		// Write control register for channel.
+
+		// Most registers are per channel, but a couple are shared; sever
+		// them here.
+		switch(pointer_) {
+			default:
+				channels_[address & 1].write(address & 2, pointer_, value);
+			break;
+
+			case 2:	// Interrupt vector register; shared between both channels.
+				interrupt_vector_ = value;
+				LOG("[SCC] Interrupt vector set to " << PADHEX(2) << int(value));
+			break;
+
+			case 9:	// Master interrupt and reset register; also shared between both channels.
+				LOG("[SCC] Master interrupt and reset register: " << PADHEX(2) << int(value));
+				master_interrupt_control_ = value;
+			break;
+		}
+
+		// The pointer number resets to 0 after every access, but if it is zero
+		// then crib at least the next set of pointer bits (which, similarly, are shared
+		// between the two channels).
+		if(pointer_) {
+			pointer_ = 0;
+		} else {
+			// The lowest three bits are the lowest three bits of the pointer.
+			pointer_ = value & 7;
+
+			// If the command part of the byte is a 'point high', also set the
+			// top bit of the pointer.
+			if(((value >> 3)&7) == 1) {
+				pointer_ |= 8;
+			}
+		}
+	}
+	update_delegate();
+}
+
+void z8530::set_dcd(int port, bool level) {
+	channels_[port].set_dcd(level);
+	update_delegate();
+}
+
+// MARK: - Channel implementations
+
+uint8_t z8530::Channel::read(bool data, uint8_t pointer) {
+	// If this is a data read, just return it.
+	if(data) {
+		return data_;
+	} else {
+		// Otherwise, this is a control read...
+		switch(pointer) {
+			default:
+				LOG("[SCC] Unrecognised control read from register " << int(pointer));
+			return 0x00;
+
+			case 0:
+			return dcd_ ? 0x8 : 0x0;
+
+			case 0xf:
+			return external_interrupt_status_;
+		}
+	}
+
+	return 0x00;
+}
+
+void z8530::Channel::write(bool data, uint8_t pointer, uint8_t value) {
+	if(data) {
+		data_ = value;
+		return;
+	} else {
+		switch(pointer) {
+			default:
+				LOG("[SCC] Unrecognised control write: " << PADHEX(2) << int(value) << " to register " << int(pointer));
+			break;
+
+			case 0x0:	// Write register 0 — CRC reset and other functions.
+				// Decode CRC reset instructions.
+				switch(value >> 6) {
+					default:	/* Do nothing. */		break;
+					case 1:
+						LOG("[SCC] TODO: reset Rx CRC checker.");
+					break;
+					case 2:
+						LOG("[SCC] TODO: reset Tx CRC checker.");
+					break;
+					case 3:
+						LOG("[SCC] TODO: reset Tx underrun/EOM latch.");
+					break;
+				}
+
+				// Decode command code.
+				switch((value >> 3)&7) {
+					default:	/* Do nothing. */		break;
+					case 2:
+//						LOG("[SCC] reset ext/status interrupts.");
+						external_status_interrupt_ = false;
+						external_interrupt_status_ = 0;
+					break;
+					case 3:
+						LOG("[SCC] TODO: send abort (SDLC).");
+					break;
+					case 4:
+						LOG("[SCC] TODO: enable interrupt on next Rx character.");
+					break;
+					case 5:
+						LOG("[SCC] TODO: reset Tx interrupt pending.");
+					break;
+					case 6:
+						LOG("[SCC] TODO: reset error.");
+					break;
+					case 7:
+						LOG("[SCC] TODO: reset highest IUS.");
+					break;
+				}
+			break;
+
+			case 0x1:	// Write register 1 — Transmit/Receive Interrupt and Data Transfer Mode Definition.
+				interrupt_mask_ = value;
+			break;
+
+			case 0x4:	// Write register 4 — Transmit/Receive Miscellaneous Parameters and Modes.
+				// Bits 0 and 1 select parity mode.
+				if(!(value&1)) {
+					parity_ = Parity::Off;
+				} else {
+					parity_ = (value&2) ? Parity::Even : Parity::Odd;
+				}
+
+				// Bits 2 and 3 select stop bits.
+				switch((value >> 2)&3) {
+					default:	stop_bits_ = StopBits::Synchronous;			break;
+					case 1:		stop_bits_ = StopBits::OneBit;				break;
+					case 2:		stop_bits_ = StopBits::OneAndAHalfBits;		break;
+					case 3:		stop_bits_ = StopBits::TwoBits;				break;
+				}
+
+				// Bits 4 and 5 pick a sync mode.
+				switch((value >> 4)&3) {
+					default:	sync_mode_ = Sync::Monosync;	break;
+					case 1:		sync_mode_ = Sync::Bisync;		break;
+					case 2:		sync_mode_ = Sync::SDLC;		break;
+					case 3:		sync_mode_ = Sync::External;	break;
+				}
+
+				// Bits 6 and 7 select a clock rate multiplier, unless synchronous
+				// mode is enabled (and this is ignored if sync mode is external).
+				if(stop_bits_ == StopBits::Synchronous) {
+					clock_rate_multiplier_ = 1;
+				} else {
+					switch((value >> 6)&3) {
+						default:	clock_rate_multiplier_ = 1;		break;
+						case 1:		clock_rate_multiplier_ = 16;	break;
+						case 2:		clock_rate_multiplier_ = 32;	break;
+						case 3:		clock_rate_multiplier_ = 64;	break;
+					}
+				}
+			break;
+
+			case 0xf:	// Write register 15 — External/Status Interrupt Control.
+				external_interrupt_mask_ = value;
+			break;
+		}
+	}
+}
+
+void z8530::Channel::set_dcd(bool level) {
+	if(dcd_ == level) return;
+	dcd_ = level;
+
+	if(external_interrupt_mask_ & 0x8) {
+		external_status_interrupt_ = true;
+		external_interrupt_status_ |= 0x8;
+	}
+}
+
+bool z8530::Channel::get_interrupt_line() {
+	return
+		(interrupt_mask_ & 1) && external_status_interrupt_;
+	// TODO: other potential causes of an interrupt.
+}
+
+void z8530::update_delegate() {
+	const bool interrupt_line = get_interrupt_line();
+	if(interrupt_line != previous_interrupt_line_) {
+		previous_interrupt_line_ = interrupt_line;
+		if(delegate_) delegate_->did_change_interrupt_status(this, interrupt_line);
+	}
+}

Components/8530/z8530.hpp

@@ -0,0 +1,99 @@
+//
+//  z8530.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef z8530_hpp
+#define z8530_hpp
+
+#include <cstdint>
+
+namespace Zilog {
+namespace SCC {
+
+/*!
+	Models the Zilog 8530 SCC, a serial adaptor.
+*/
+class z8530 {
+	public:
+		/*
+			**Interface for emulated machine.**
+
+			Notes on addressing below:
+
+			There's no inherent ordering of the two 'address' lines,
+			A/B and C/D, but the methods below assume:
+
+				A/B = A0
+				C/D = A1
+		*/
+		std::uint8_t read(int address);
+		void write(int address, std::uint8_t value);
+		void reset();
+		bool get_interrupt_line();
+
+		struct Delegate {
+			virtual void did_change_interrupt_status(z8530 *, bool new_status) = 0;
+		};
+		void set_delegate(Delegate *delegate) {
+			delegate_ = delegate;
+		}
+
+		/*
+			**Interface for serial port input.**
+		*/
+		void set_dcd(int port, bool level);
+
+	private:
+		class Channel {
+			public:
+				uint8_t read(bool data, uint8_t pointer);
+				void write(bool data, uint8_t pointer, uint8_t value);
+				void set_dcd(bool level);
+				bool get_interrupt_line();
+
+			private:
+				uint8_t data_ = 0xff;
+
+				enum class Parity {
+					Even, Odd, Off
+				} parity_ = Parity::Off;
+
+				enum class StopBits {
+					Synchronous, OneBit, OneAndAHalfBits, TwoBits
+				} stop_bits_ = StopBits::Synchronous;
+
+				enum class Sync {
+					Monosync, Bisync, SDLC, External
+				} sync_mode_ = Sync::Monosync;
+
+				int clock_rate_multiplier_ = 1;
+
+				uint8_t interrupt_mask_ = 0;			// i.e. Write Register 0x1.
+
+				uint8_t external_interrupt_mask_ = 0;	// i.e. Write Register 0xf.
+				bool external_status_interrupt_ = false;
+				uint8_t external_interrupt_status_ = 0;
+
+				bool dcd_ = false;
+		} channels_[2];
+
+		uint8_t pointer_ = 0;
+
+		uint8_t interrupt_vector_ = 0;
+
+		uint8_t master_interrupt_control_ = 0;
+
+		bool previous_interrupt_line_ = false;
+		void update_delegate();
+		Delegate *delegate_ = nullptr;
+};
+
+}
+}
+
+
+#endif /* z8530_hpp */

Components/AY38910/AY38910.cpp

@@ -173,11 +173,15 @@ void AY38910::select_register(uint8_t r) {
 }
 
 void AY38910::set_register_value(uint8_t value) {
+	// There are only 16 registers.
 	if(selected_register_ > 15) return;
-	registers_[selected_register_] = value;
+
+	// If this is a register that affects audio output, enqueue a mutation onto the
+	// audio generation thread.
 	if(selected_register_ < 14) {
-		int selected_register = selected_register_;
+		const int selected_register = selected_register_;
 		task_queue_.defer([=] () {
+			// Perform any register-specific mutation to output generation.
 			uint8_t masked_value = value;
 			switch(selected_register) {
 				case 0: case 2: case 4:
@@ -208,12 +212,34 @@ void AY38910::set_register_value(uint8_t value) {
 					envelope_position_ = 0;
 				break;
 			}
+
+			// Store a copy of the current register within the storage used by the audio generation
+			// thread, and apply any changes to output volume.
 			output_registers_[selected_register] = masked_value;
 			evaluate_output_volume();
 		});
-	} else {
-		if(port_handler_) port_handler_->set_port_output(selected_register_ == 15, value);
 	}
+
+	// Decide which outputs are going to need updating (if any).
+	bool update_port_a = false;
+	bool update_port_b = true;
+	if(port_handler_) {
+		if(selected_register_ == 7) {
+			const uint8_t io_change = registers_[7] ^ value;
+			update_port_b = !!(io_change&0x80);
+			update_port_a = !!(io_change&0x40);
+		} else {
+			update_port_b = selected_register_ == 15;
+			update_port_a = selected_register_ != 15;
+		}
+	}
+
+	// Keep a copy of the new value that is usable from the emulation thread.
+	registers_[selected_register_] = value;
+
+	// Update ports as required.
+	if(update_port_b) set_port_output(true);
+	if(update_port_a) set_port_output(false);
 }
 
 uint8_t AY38910::get_register_value() {
@@ -238,6 +264,8 @@ uint8_t AY38910::get_port_output(bool port_b) {
 
 void AY38910::set_port_handler(PortHandler *handler) {
 	port_handler_ = handler;
+	set_port_output(true);
+	set_port_output(false);
 }
 
 void AY38910::set_data_input(uint8_t r) {
@@ -245,6 +273,16 @@ void AY38910::set_data_input(uint8_t r) {
 	update_bus();
 }
 
+void AY38910::set_port_output(bool port_b) {
+	// Per the data sheet: "each [IO] pin is provided with an on-chip pull-up resistor,
+	// so that when in the "input" mode, all pins will read normally high". Therefore,
+	// report programmer selection of input mode as creating an output of 0xff.
+	if(port_handler_) {
+		const bool is_output = !!(registers_[7] & (port_b ? 0x80 : 0x40));
+		port_handler_->set_port_output(port_b, is_output ? registers_[port_b ? 15 : 14] : 0xff);
+	}
+}
+
 uint8_t AY38910::get_data_output() {
 	if(control_state_ == Read && selected_register_ >= 14 && selected_register_ < 16) {
 		// Per http://cpctech.cpc-live.com/docs/psgnotes.htm if a port is defined as output then the

Components/AY38910/AY38910.hpp

@@ -83,7 +83,7 @@ class AY38910: public ::Outputs::Speaker::SampleSource {
 		*/
 		void set_port_handler(PortHandler *);
 
-		// to satisfy ::Outputs::Speaker (included via ::Outputs::Filter; not for public consumption
+		// to satisfy ::Outputs::Speaker (included via ::Outputs::Filter.
 		void get_samples(std::size_t number_of_samples, int16_t *target);
 		bool is_zero_level();
 		void set_sample_volume_range(std::int16_t range);
@@ -128,10 +128,11 @@ class AY38910: public ::Outputs::Speaker::SampleSource {
 		uint8_t data_input_, data_output_;
 
 		int16_t output_volume_;
-		inline void evaluate_output_volume();
+		void evaluate_output_volume();
 
-		inline void update_bus();
+		void update_bus();
 		PortHandler *port_handler_ = nullptr;
+		void set_port_output(bool port_b);
 };
 
 }

Components/DiskII/DiskII.cpp

@@ -22,7 +22,7 @@ namespace  {
 DiskII::DiskII(int clock_rate) :
 	clock_rate_(clock_rate),
 	inputs_(input_command),
-	drives_{{static_cast<unsigned int>(clock_rate), 300, 1}, {static_cast<unsigned int>(clock_rate), 300, 1}}
+	drives_{{clock_rate, 300, 1}, {clock_rate, 300, 1}}
 {
 	drives_[0].set_clocking_hint_observer(this);
 	drives_[1].set_clocking_hint_observer(this);
@@ -211,7 +211,7 @@ void DiskII::set_disk(const std::shared_ptr<Storage::Disk::Disk> &disk, int driv
 	drives_[drive].set_disk(disk);
 }
 
-void DiskII::process_event(const Storage::Disk::Track::Event &event) {
+void DiskII::process_event(const Storage::Disk::Drive::Event &event) {
 	if(event.type == Storage::Disk::Track::Event::FluxTransition) {
 		inputs_ &= ~input_flux;
 		flux_duration_ = 2;	// Upon detection of a flux transition, the flux flag should stay set for 1us. Emulate that as two cycles.

Components/DiskII/DiskII.hpp

@@ -98,7 +98,7 @@ class DiskII:
 		void select_drive(int drive);
 
 		uint8_t trigger_address(int address, uint8_t value);
-		void process_event(const Storage::Disk::Track::Event &event) override;
+		void process_event(const Storage::Disk::Drive::Event &event) override;
 		void set_component_prefers_clocking(ClockingHint::Source *component, ClockingHint::Preference preference) override;
 
 		const int clock_rate_ = 0;

Components/DiskII/IWM.cpp

@@ -0,0 +1,376 @@
+//
+//  IWM.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 05/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "IWM.hpp"
+
+#include "../../Outputs/Log.hpp"
+
+using namespace Apple;
+
+namespace  {
+	const int CA0		= 1 << 0;
+	const int CA1		= 1 << 1;
+	const int CA2		= 1 << 2;
+	const int LSTRB		= 1 << 3;
+	const int ENABLE	= 1 << 4;
+	const int DRIVESEL	= 1 << 5;	/* This means drive select, like on the original Disk II. */
+	const int Q6		= 1 << 6;
+	const int Q7		= 1 << 7;
+	const int SEL		= 1 << 8;	/* This is an additional input, not available on a Disk II, with a confusingly-similar name to SELECT but a distinct purpose. */
+}
+
+IWM::IWM(int clock_rate) :
+	clock_rate_(clock_rate) {}
+
+// MARK: - Bus accessors
+
+uint8_t IWM::read(int address) {
+	access(address);
+
+	// Per Inside Macintosh:
+	//
+	// "Before you can read from any of the disk registers you must set up the state of the IWM so that it
+	// can pass the data through to the MC68000's address space where you'll be able to read it. To do that,
+	// you must first turn off Q7 by reading or writing dBase+q7L. Then turn on Q6 by accessing dBase+q6H.
+	// After that, the IWM will be able to pass data from the disk's RD/SENSE line through to you."
+	//
+	// My understanding:
+	//
+	//	Q6 = 1, Q7 = 0 reads the status register. The meaning of the top 'SENSE' bit is then determined by
+	//	the CA0,1,2 and SEL switches as described in Inside Macintosh, summarised above as RD/SENSE.
+
+	if(address&1) {
+		return 0xff;
+	}
+
+	switch(state_ & (Q6 | Q7 | ENABLE)) {
+		default:
+			LOG("[IWM] Invalid read\n");
+		return 0xff;
+
+		// "Read all 1s".
+//			printf("Reading all 1s\n");
+//		return 0xff;
+
+		case 0:
+		case ENABLE: {				/* Read data register. Zeroing afterwards is a guess. */
+			const auto result = data_register_;
+
+			if(data_register_ & 0x80) {
+//				printf("\n\nIWM:%02x\n\n", data_register_);
+//				printf(".");
+				data_register_ = 0;
+			}
+//			LOG("Reading data register: " << PADHEX(2) << int(result));
+
+			return result;
+		}
+
+		case Q6: case Q6|ENABLE: {
+			/*
+				[If A = 0], Read status register:
+
+				bits 0-4: same as mode register.
+				bit 5: 1 = either /ENBL1 or /ENBL2 is currently low.
+				bit 6: 1 = MZ (reserved for future compatibility; should always be read as 0).
+				bit 7: 1 = SENSE input high; 0 = SENSE input low.
+
+				(/ENBL1 is low when the first drive's motor is on; /ENBL2 is low when the second drive's motor is on.
+				If the 1-second timer is enabled, motors remain on for one second after being programmatically disabled.)
+			*/
+
+			return uint8_t(
+				(mode_&0x1f) |
+				((state_ & ENABLE) ? 0x20 : 0x00) |
+				(sense() & 0x80)
+			);
+		} break;
+
+		case Q7: case Q7|ENABLE:
+			/*
+				Read write-handshake register:
+
+				bits 0-5: reserved for future use (currently read as 1).
+				bit 6: 1 = write state (0 = underrun has occurred; 1 = no underrun so far).
+				bit 7: 1 = write data buffer ready for data (1 = ready; 0 = busy).
+			*/
+//			LOG("Reading write handshake: " << PADHEX(2) << (0x3f | write_handshake_));
+		return 0x3f | write_handshake_;
+	}
+
+	return 0xff;
+}
+
+void IWM::write(int address, uint8_t input) {
+	access(address);
+
+	switch(state_ & (Q6 | Q7 | ENABLE)) {
+		default: break;
+
+		case Q7|Q6:
+			/*
+				Write mode register:
+
+				bit 0: 1 = latch mode (should be set in asynchronous mode).
+				bit 1: 0 = synchronous handshake protocol; 1 = asynchronous.
+				bit 2: 0 = 1-second on-board timer enable; 1 = timer disable.
+				bit 3: 0 = slow mode; 1 = fast mode.
+				bit 4: 0 = 7Mhz; 1 = 8Mhz (7 or 8 mHz clock descriptor).
+				bit 5: 1 = test mode; 0 = normal operation.
+				bit 6: 1 = MZ-reset.
+				bit 7: reserved for future expansion.
+			*/
+
+			mode_ = input;
+
+			switch(mode_ & 0x18) {
+				case 0x00:		bit_length_ = Cycles(24);		break;	// slow mode, 7Mhz
+				case 0x08:		bit_length_ = Cycles(12);		break;	// fast mode, 7Mhz
+				case 0x10:		bit_length_ = Cycles(32);		break;	// slow mode, 8Mhz
+				case 0x18:		bit_length_ = Cycles(16);		break;	// fast mode, 8Mhz
+			}
+			LOG("IWM mode is now " << PADHEX(2) << int(mode_));
+		break;
+
+		case Q7|Q6|ENABLE:	// Write data register.
+			next_output_ = input;
+			write_handshake_ &= ~0x80;
+		break;
+	}
+}
+
+// MARK: - Switch access
+
+void IWM::access(int address) {
+	// Keep a record of switch state; bits in state_
+	// should correlate with the anonymous namespace constants
+	// defined at the top of this file — CA0, CA1, etc.
+	address &= 0xf;
+	const auto mask = 1 << (address >> 1);
+	const auto old_state = state_;
+
+	if(address & 1) {
+		state_ |= mask;
+	} else {
+		state_ &= ~mask;
+	}
+
+	// React appropriately to ENABLE and DRIVESEL changes, and changes into/out of write mode.
+	if(old_state != state_) {
+		push_drive_state();
+
+		switch(mask) {
+			default: break;
+
+			case ENABLE:
+				if(address & 1) {
+					if(drives_[active_drive_]) drives_[active_drive_]->set_enabled(true);
+				} else {
+					// If the 1-second delay is enabled, set up a timer for that.
+					if(!(mode_ & 4)) {
+						cycles_until_disable_ = Cycles(clock_rate_);
+					} else {
+						if(drives_[active_drive_]) drives_[active_drive_]->set_enabled(false);
+					}
+				}
+			break;
+
+			case DRIVESEL: {
+				const int new_drive = address & 1;
+				if(new_drive != active_drive_) {
+					if(drives_[active_drive_]) drives_[active_drive_]->set_enabled(false);
+					active_drive_ = new_drive;
+					if(drives_[active_drive_]) {
+						drives_[active_drive_]->set_enabled(state_ & ENABLE || (cycles_until_disable_ > Cycles(0)));
+						push_drive_state();
+					}
+				}
+			} break;
+
+			case Q6:
+			case Q7:
+				select_shift_mode();
+			break;
+		}
+	}
+}
+
+void IWM::set_select(bool enabled) {
+	// Store SEL as an extra state bit.
+	if(enabled) state_ |= SEL;
+	else state_ &= ~SEL;
+	push_drive_state();
+}
+
+void IWM::push_drive_state() {
+	if(drives_[active_drive_])  {
+		const uint8_t drive_control_lines =
+			((state_ & CA0) ? IWMDrive::CA0 : 0) |
+			((state_ & CA1) ? IWMDrive::CA1 : 0) |
+			((state_ & CA2) ? IWMDrive::CA2 : 0) |
+			((state_ & SEL) ? IWMDrive::SEL : 0) |
+			((state_ & LSTRB) ? IWMDrive::LSTRB : 0);
+		drives_[active_drive_]->set_control_lines(drive_control_lines);
+	}
+}
+
+// MARK: - Active logic
+
+void IWM::run_for(const Cycles cycles) {
+	// Check for a timeout of the motor-off timer.
+	if(cycles_until_disable_ > Cycles(0)) {
+		cycles_until_disable_ -= cycles;
+		if(cycles_until_disable_ <= Cycles(0)) {
+			cycles_until_disable_ = Cycles(0);
+			if(drives_[active_drive_])
+				drives_[active_drive_]->set_enabled(false);
+		}
+	}
+
+	// Activity otherwise depends on mode and motor state.
+	int integer_cycles = cycles.as_int();
+	switch(shift_mode_) {
+		case ShiftMode::Reading:
+			if(drive_is_rotating_[active_drive_]) {
+				while(integer_cycles--) {
+					drives_[active_drive_]->run_for(Cycles(1));
+					++cycles_since_shift_;
+					if(cycles_since_shift_ == bit_length_ + Cycles(2)) {
+						propose_shift(0);
+					}
+				}
+			} else {
+				while(cycles_since_shift_ + integer_cycles >= bit_length_ + Cycles(2)) {
+					propose_shift(0);
+					integer_cycles -= bit_length_.as_int() + 2 - cycles_since_shift_.as_int();
+				}
+				cycles_since_shift_ += Cycles(integer_cycles);
+			}
+		break;
+
+		case ShiftMode::Writing:
+			if(drives_[active_drive_]->is_writing()) {
+				while(cycles_since_shift_ + integer_cycles >= bit_length_) {
+					const auto cycles_until_write = bit_length_ - cycles_since_shift_;
+					drives_[active_drive_]->run_for(cycles_until_write);
+
+					// Output a flux transition if the top bit is set.
+					drives_[active_drive_]->write_bit(shift_register_ & 0x80);
+					shift_register_ <<= 1;
+
+					integer_cycles -= cycles_until_write.as_int();
+					cycles_since_shift_ = Cycles(0);
+
+					--output_bits_remaining_;
+					if(!output_bits_remaining_) {
+						if(!(write_handshake_ & 0x80)) {
+							write_handshake_ |= 0x80;
+							shift_register_ = next_output_;
+							output_bits_remaining_ = 8;
+//							LOG("Next byte: " << PADHEX(2) << int(shift_register_));
+						} else {
+							write_handshake_ &= ~0x40;
+							drives_[active_drive_]->end_writing();
+//							printf("\n");
+							LOG("Overrun; done.");
+							select_shift_mode();
+						}
+					}
+				}
+
+				cycles_since_shift_ = integer_cycles;
+				if(integer_cycles) {
+					drives_[active_drive_]->run_for(cycles_since_shift_);
+				}
+			} else {
+				drives_[active_drive_]->run_for(cycles);
+			}
+		break;
+
+		case ShiftMode::CheckingWriteProtect:
+			if(integer_cycles < 8) {
+				shift_register_ = (shift_register_ >> integer_cycles) | (sense() & (0xff << (8 - integer_cycles)));
+			} else {
+				shift_register_ = sense();
+			}
+
+		/* Deliberate fallthrough. */
+		default:
+			if(drive_is_rotating_[active_drive_]) drives_[active_drive_]->run_for(cycles);
+		break;
+	}
+}
+
+void IWM::select_shift_mode() {
+	// Don't allow an ongoing write to be interrupted.
+	if(shift_mode_ == ShiftMode::Writing && drives_[active_drive_] && drives_[active_drive_]->is_writing()) return;
+
+	const auto old_shift_mode = shift_mode_;
+
+	switch(state_ & (Q6|Q7)) {
+		default:	shift_mode_ = ShiftMode::CheckingWriteProtect;		break;
+		case 0:		shift_mode_ = ShiftMode::Reading;					break;
+		case Q7:
+			// "The IWM is put into the write state by a transition from the write protect sense state to the
+			// write load state".
+			if(shift_mode_ == ShiftMode::CheckingWriteProtect) shift_mode_ = ShiftMode::Writing;
+		break;
+	}
+
+	// If writing mode just began, set the drive into write mode and cue up the first output byte.
+	if(drives_[active_drive_] && old_shift_mode != ShiftMode::Writing && shift_mode_ == ShiftMode::Writing) {
+		drives_[active_drive_]->begin_writing(Storage::Time(1, clock_rate_ / bit_length_.as_int()), false);
+		shift_register_ = next_output_;
+		write_handshake_ |= 0x80 | 0x40;
+		output_bits_remaining_ = 8;
+		LOG("Seeding output with " << PADHEX(2) << shift_register_);
+	}
+}
+
+uint8_t IWM::sense() {
+	return drives_[active_drive_] ? (drives_[active_drive_]->read() ? 0xff : 0x00) : 0xff;
+}
+
+void IWM::process_event(const Storage::Disk::Drive::Event &event) {
+	if(shift_mode_ != ShiftMode::Reading) return;
+
+	switch(event.type) {
+		case Storage::Disk::Track::Event::IndexHole: return;
+		case Storage::Disk::Track::Event::FluxTransition:
+			propose_shift(1);
+		break;
+	}
+}
+
+void IWM::propose_shift(uint8_t bit) {
+	// TODO: synchronous mode.
+
+//	LOG("Shifting input");
+	shift_register_ = uint8_t((shift_register_ << 1) | bit);
+	if(shift_register_ & 0x80) {
+		data_register_ = shift_register_;
+		shift_register_ = 0;
+	}
+	cycles_since_shift_ = Cycles(0);
+}
+
+void IWM::set_drive(int slot, IWMDrive *drive) {
+	drives_[slot] = drive;
+	drive->set_event_delegate(this);
+	drive->set_clocking_hint_observer(this);
+}
+
+void IWM::set_component_prefers_clocking(ClockingHint::Source *component, ClockingHint::Preference clocking) {
+	const bool is_rotating = clocking != ClockingHint::Preference::None;
+
+	if(component == static_cast<ClockingHint::Source *>(drives_[0])) {
+		drive_is_rotating_[0] = is_rotating;
+	} else {
+		drive_is_rotating_[1] = is_rotating;
+	}
+}

Components/DiskII/IWM.hpp

@@ -0,0 +1,117 @@
+//
+//  IWM.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 05/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef IWM_hpp
+#define IWM_hpp
+
+#include "../../ClockReceiver/ClockReceiver.hpp"
+#include "../../ClockReceiver/ClockingHintSource.hpp"
+#include "../../Storage/Disk/Drive.hpp"
+
+#include <cstdint>
+
+namespace Apple {
+
+/*!
+	Defines the drive interface used by the IWM, derived from the external pinout as
+	per e.g. https://old.pinouts.ru/HD/MacExtDrive_pinout.shtml
+
+	These are subclassed of Storage::Disk::Drive, so accept any disk the emulator supports,
+	and provide the usual read/write interface for on-disk data.
+*/
+struct IWMDrive: public Storage::Disk::Drive {
+	IWMDrive(int input_clock_rate, int number_of_heads) : Storage::Disk::Drive(input_clock_rate, number_of_heads) {}
+
+	enum Line: int {
+		CA0		= 1 << 0,
+		CA1		= 1 << 1,
+		CA2		= 1 << 2,
+		LSTRB	= 1 << 3,
+		SEL		= 1 << 4,
+	};
+
+	virtual void set_enabled(bool) = 0;
+	virtual void set_control_lines(int) = 0;
+	virtual bool read() = 0;
+};
+
+class IWM:
+	public Storage::Disk::Drive::EventDelegate,
+	public ClockingHint::Observer {
+	public:
+		IWM(int clock_rate);
+
+		/// Sets the current external value of the data bus.
+		void write(int address, uint8_t value);
+
+		/*!
+			Submits an access to address @c address.
+
+			@returns The 8-bit value loaded to the data bus by the IWM.
+		*/
+		uint8_t read(int address);
+
+		/*!
+			Sets the current input of the IWM's SEL line.
+		*/
+		void set_select(bool enabled);
+
+		/// Advances the controller by @c cycles.
+		void run_for(const Cycles cycles);
+
+		/// Connects a drive to the IWM.
+		void set_drive(int slot, IWMDrive *drive);
+
+	private:
+		// Storage::Disk::Drive::EventDelegate.
+		void process_event(const Storage::Disk::Drive::Event &event) override;
+
+		const int clock_rate_;
+
+		uint8_t data_register_ = 0;
+		uint8_t mode_ = 0;
+		bool read_write_ready_ = true;
+		bool write_overran_ = false;
+
+		int state_ = 0;
+
+		int active_drive_ = 0;
+		IWMDrive *drives_[2] = {nullptr, nullptr};
+		bool drive_is_rotating_[2] = {false, false};
+
+		void set_component_prefers_clocking(ClockingHint::Source *component, ClockingHint::Preference clocking) override;
+
+		Cycles cycles_until_disable_;
+		uint8_t write_handshake_ = 0x80;
+
+		void access(int address);
+
+		uint8_t shift_register_ = 0;
+		uint8_t next_output_ = 0;
+		int output_bits_remaining_ = 0;
+
+		void propose_shift(uint8_t bit);
+		Cycles cycles_since_shift_;
+		Cycles bit_length_ = Cycles(16);
+
+		void push_drive_state();
+
+		enum class ShiftMode {
+			Reading,
+			Writing,
+			CheckingWriteProtect
+		} shift_mode_;
+
+		uint8_t sense();
+		void select_shift_mode();
+};
+
+
+}
+
+#endif /* IWM_hpp */

Components/DiskII/MacintoshDoubleDensityDrive.cpp

@@ -0,0 +1,179 @@
+//
+//  MacintoshDoubleDensityDrive.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 10/07/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "MacintoshDoubleDensityDrive.hpp"
+
+/*
+	Sources used pervasively:
+
+	http://members.iinet.net.au/~kalandi/apple/AUG/1991/11%20NOV.DEC/DISK.STUFF.html
+	Apple Guide to the Macintosh Family Hardware
+	Inside Macintosh III
+*/
+
+using namespace Apple::Macintosh;
+
+DoubleDensityDrive::DoubleDensityDrive(int input_clock_rate, bool is_800k) :
+	IWMDrive(input_clock_rate, is_800k ? 2 : 1),	// Only 800kb drives are double sided.
+	is_800k_(is_800k) {
+	// Start with a valid rotation speed.
+	if(is_800k) {
+		Drive::set_rotation_speed(393.3807f);
+	}
+}
+
+// MARK: - Speed Selection
+
+void DoubleDensityDrive::did_step(Storage::Disk::HeadPosition to_position) {
+//	printf("At track %d\n", to_position.as_int());
+	// The 800kb drive automatically selects rotation speed as a function of
+	// head position; the 400kb drive doesn't do so.
+	if(is_800k_) {
+		/*
+			Numbers below cribbed from the Kryoflux forums; specifically:
+			https://forum.kryoflux.com/viewtopic.php?t=1090
+
+			They can almost be worked out algorithmically, since the point is to
+			produce an almost-constant value for speed*(number of sectors), and:
+
+			393.3807 * 12 = 4720.5684
+			429.1723 * 11 = 4720.895421
+			472.1435 * 10 = 4721.435
+			524.5672 * 9 = 4721.1048
+			590.1098 * 8 = 4720.8784
+
+			So 4721 / (number of sectors per track in zone) would give essentially
+			the same results.
+		*/
+		const int zone = to_position.as_int() >> 4;
+		switch(zone) {
+			case 0:		Drive::set_rotation_speed(393.3807f);	break;
+			case 1:		Drive::set_rotation_speed(429.1723f);	break;
+			case 2:		Drive::set_rotation_speed(472.1435f);	break;
+			case 3:		Drive::set_rotation_speed(524.5672f);	break;
+			default:	Drive::set_rotation_speed(590.1098f);	break;
+		}
+	}
+}
+
+void DoubleDensityDrive::set_rotation_speed(float revolutions_per_minute) {
+	if(!is_800k_) {
+		// Don't allow drive speeds to drop below 10 RPM, as a temporary sop
+		// to sanity.
+		Drive::set_rotation_speed(std::max(10.0f, revolutions_per_minute));
+	}
+}
+
+// MARK: - Control input/output.
+
+void DoubleDensityDrive::set_enabled(bool) {
+}
+
+void DoubleDensityDrive::set_control_lines(int lines) {
+	const auto old_state = control_state_;
+	control_state_ = lines;
+
+	// Catch low-to-high LSTRB transitions.
+	if((old_state ^ control_state_) & control_state_ & Line::LSTRB) {
+		switch(control_state_ & (Line::CA2 | Line::CA1 | Line::CA0 | Line::SEL)) {
+			default:
+			break;
+
+			case 0:						// Set step direction — CA2 set => step outward.
+			case Line::CA2:
+				step_direction_ = (control_state_ & Line::CA2) ? -1 : 1;
+			break;
+
+			case Line::CA1:				// Set drive motor — CA2 set => motor off.
+			case Line::CA1|Line::CA2:
+				set_motor_on(!(control_state_ & Line::CA2));
+			break;
+
+			case Line::CA0:				// Initiate a step.
+				step(Storage::Disk::HeadPosition(step_direction_));
+			break;
+
+			case Line::SEL|Line::CA2:	// Reset new disk flag.
+				has_new_disk_ = false;
+			break;
+
+			case Line::CA2 | Line::CA1 | Line::CA0:	// Eject the disk.
+				set_disk(nullptr);
+			break;
+		}
+	}
+}
+
+bool DoubleDensityDrive::read() {
+	switch(control_state_ & (CA2 | CA1 | CA0 | SEL)) {
+		default:
+		return false;
+
+		case 0:					// Head step direction.
+								// (0 = inward)
+		return step_direction_ <= 0;
+
+		case SEL:				// Disk in place.
+								// (0 = disk present)
+		return !has_disk();
+
+		case CA0:				// Disk head step completed.
+								// (0 = still stepping)
+		return true;	// TODO: stepping delay. But at the main Drive level.
+
+		case CA0|SEL:			// Disk locked.
+								// (0 = write protected)
+		return !get_is_read_only();
+
+		case CA1:				// Disk motor running.
+								// (0 = motor on)
+		return !get_motor_on();
+
+		case CA1|SEL:			// Head at track 0.
+								// (0 = at track 0)
+								// "This bit becomes valid beginning 12 msec after the step that places the head at track 0."
+		return !get_is_track_zero();
+
+		case CA1|CA0:			// Disk has been ejected.
+								// (0 = user has ejected disk)
+		return !has_new_disk_;
+
+		case CA1|CA0|SEL:		// Tachometer.
+								// (arbitrary)
+		return get_tachometer();
+
+		case CA2:				// Read data, lower head.
+			set_head(0);
+		return false;
+
+		case CA2|SEL:			// Read data, upper head.
+			set_head(1);
+		return false;
+
+		case CA2|CA1:			// Single- or double-sided drive.
+								// (0 = single sided)
+		return get_head_count() != 1;
+
+		case CA2|CA1|CA0:		// "Present/HD" (per the Mac Plus ROM)
+								// (0 = ??HD??)
+								//
+								// Alternative explanation: "Disk ready for reading?"
+								// (0 = ready)
+		return false;
+
+		case CA2|CA1|CA0|SEL:	// Drive installed.
+								// (0 = present, 1 = missing)
+								//
+								// TODO: why do I need to return this the wrong way around for the Mac Plus?
+		return true;
+	}
+}
+
+void DoubleDensityDrive::did_set_disk() {
+	has_new_disk_ = true;
+}

Components/DiskII/MacintoshDoubleDensityDrive.hpp

@@ -0,0 +1,53 @@
+//
+//  MacintoshDoubleDensityDrive.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 10/07/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef MacintoshDoubleDensityDrive_hpp
+#define MacintoshDoubleDensityDrive_hpp
+
+#include "IWM.hpp"
+
+namespace Apple {
+namespace Macintosh {
+
+class DoubleDensityDrive: public IWMDrive {
+	public:
+		DoubleDensityDrive(int input_clock_rate, bool is_800k);
+
+		/*!
+			@returns @c true if this is an 800kb drive; @c false otherwise.
+		*/
+		bool is_800k() {
+			return is_800k_;
+		}
+
+		/*!
+			Sets the current rotation speed of this drive only if it is a 400kb drive.
+			800kb drives select their own rotation speed based on head position,
+			and ignore this input.
+		*/
+		void set_rotation_speed(float revolutions_per_minute);
+
+		void set_enabled(bool) override;
+		void set_control_lines(int) override;
+		bool read() override;
+
+	private:
+		// To receive the proper notifications from Storage::Disk::Drive.
+		void did_step(Storage::Disk::HeadPosition to_position) override;
+		void did_set_disk() override;
+
+		const bool is_800k_;
+		bool has_new_disk_ = false;
+		int control_state_ = 0;
+		int step_direction_ = 1;
+};
+
+}
+}
+
+#endif /* MacintoshDoubleDensityDrive_hpp */

Inputs/Keyboard.hpp

@@ -6,8 +6,8 @@
 //  Copyright 2017 Thomas Harte. All rights reserved.
 //
 
-#ifndef Keyboard_hpp
-#define Keyboard_hpp
+#ifndef Inputs_Keyboard_hpp
+#define Inputs_Keyboard_hpp
 
 #include <vector>
 #include <set>
@@ -75,4 +75,4 @@ class Keyboard {
 
 }
 
-#endif /* Keyboard_hpp */
+#endif /* Inputs_Keyboard_hpp */

Inputs/Mouse.hpp

@@ -0,0 +1,47 @@
+//
+//  Mouse.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 11/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef Mouse_h
+#define Mouse_h
+
+namespace Inputs {
+
+/*!
+	Models a classic-era mouse: something that provides 2d relative motion plus
+	some quantity of buttons.
+*/
+class Mouse {
+	public:
+		/*!
+			Indicates a movement of the mouse.
+		*/
+		virtual void move(int x, int y) {}
+
+		/*!
+			@returns the number of buttons on this mouse.
+		*/
+		virtual int get_number_of_buttons() {
+			return 1;
+		}
+
+		/*!
+			Indicates that button @c index is now either pressed or unpressed.
+			The intention is that @c index be semantic, not positional:
+			0 for the primary button, 1 for the secondary, 2 for the tertiary, etc.
+		*/
+		virtual void set_button_pressed(int index, bool is_pressed) {}
+
+		/*!
+			Releases all depressed buttons.
+		*/
+		virtual void reset_all_buttons() {}
+};
+
+}
+
+#endif /* Mouse_h */

Inputs/QuadratureMouse/QuadratureMouse.hpp

@@ -0,0 +1,123 @@
+//
+//  QuadratureMouse.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 11/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef QuadratureMouse_hpp
+#define QuadratureMouse_hpp
+
+#include "../Mouse.hpp"
+#include <atomic>
+
+namespace Inputs {
+
+/*!
+	Provides a simple implementation of a Mouse, designed for simple
+	thread-safe feeding to a machine that accepts quadrature-encoded input.
+
+	TEMPORARY SIMPLIFICATION: it is assumed that the caller will be interested
+	in observing a signal that dictates velocity, sampling the other to
+	obtain direction only on transitions in the velocity signal.
+
+	Or, more concretely, of the two channels per axis, one is accurate only when
+	the other transitions. Hence the discussion of 'primary' and 'secondary'
+	channels below. This is intended to be fixed.
+*/
+class QuadratureMouse: public Mouse {
+	public:
+		QuadratureMouse(int number_of_buttons) :
+			number_of_buttons_(number_of_buttons) {}
+
+		/*
+			Inputs, to satisfy the Mouse interface.
+		*/
+		void move(int x, int y) override {
+			// Accumulate all provided motion.
+			axes_[0] += x;
+			axes_[1] += y;
+		}
+
+		int get_number_of_buttons() override {
+			return number_of_buttons_;
+		}
+
+		void set_button_pressed(int index, bool is_pressed) override {
+			if(is_pressed)
+				button_flags_ |= (1 << index);
+			else
+				button_flags_ &= ~(1 << index);
+		}
+
+		void reset_all_buttons() override {
+			button_flags_ = 0;
+		}
+
+		/*
+			Outputs.
+		*/
+
+		/*!
+			Applies a single step from the current accumulated mouse movement, which
+			might involve the mouse moving right, or left, or not at all.
+		*/
+		void prepare_step() {
+			for(int axis = 0; axis < 2; ++axis) {
+				// Do nothing if there's no motion to communicate.
+				const int axis_value = axes_[axis];
+				if(!axis_value) continue;
+
+				// Toggle the primary channel and set the secondary for
+				// negative motion. At present the y axis signals the
+				// secondary channel the opposite way around from the
+				// primary.
+				primaries_[axis] ^= 1;
+				secondaries_[axis] = primaries_[axis] ^ axis;
+				if(axis_value > 0) {
+					-- axes_[axis];
+					secondaries_[axis] ^= 1;	// Switch to positive motion.
+				} else {
+					++ axes_[axis];
+				}
+			}
+		}
+
+		/*!
+			@returns the two quadrature channels — bit 0 is the 'primary' channel
+				(i.e. the one that can be monitored to observe velocity) and
+				bit 1 is the 'secondary' (i.e. that which can be queried to
+				observe direction).
+		*/
+		int get_channel(int axis) {
+			return primaries_[axis] | (secondaries_[axis] << 1);
+		}
+
+		/*!
+			@returns a bit mask of the currently pressed buttons.
+		*/
+		int get_button_mask() {
+			return button_flags_;
+		}
+
+		/*!
+			@returns @c true if any mouse motion is waiting to be communicated;
+				@c false otherwise.
+		*/
+		bool has_steps() {
+			return axes_[0] || axes_[1];
+		}
+
+	private:
+		int number_of_buttons_ = 0;
+		std::atomic<int> button_flags_;
+		std::atomic<int> axes_[2];
+
+		int primaries_[2] = {0, 0};
+		int secondaries_[2] = {0, 0};
+};
+
+}
+
+#endif /* QuadratureMouse_hpp */

Machines/AmstradCPC/AmstradCPC.cpp

@@ -781,27 +781,37 @@ template <bool has_fdc> class ConcreteMachine:
 			ay_.ay().set_port_handler(&key_state_);
 
 			// construct the list of necessary ROMs
-			std::vector<std::string> required_roms = {"amsdos.rom"};
+			const std::string machine_name = "AmstradCPC";
+			std::vector<ROMMachine::ROM> required_roms = {
+				ROMMachine::ROM(machine_name, "the Amstrad Disk Operating System", "amsdos.rom", 16*1024, 0x1fe22ecd)
+			};
 			std::string model_number;
+			uint32_t crcs[2];
 			switch(target.model) {
 				default:
 					model_number = "6128";
 					has_128k_ = true;
+					crcs[0] = 0x0219bb74;
+					crcs[1] = 0xca6af63d;
 				break;
 				case Analyser::Static::AmstradCPC::Target::Model::CPC464:
 					model_number = "464";
 					has_128k_ = false;
+					crcs[0] = 0x815752df;
+					crcs[1] = 0x7d9a3bac;
 				break;
 				case Analyser::Static::AmstradCPC::Target::Model::CPC664:
 					model_number = "664";
 					has_128k_ = false;
+					crcs[0] = 0x3f5a6dc4;
+					crcs[1] = 0x32fee492;
 				break;
 			}
-			required_roms.push_back("os" + model_number + ".rom");
-			required_roms.push_back("basic" + model_number + ".rom");
+			required_roms.emplace_back(machine_name, "the CPC " + model_number + " firmware", "os" + model_number + ".rom", 16*1024, crcs[0]);
+			required_roms.emplace_back(machine_name, "the CPC " + model_number + " BASIC ROM", "basic" + model_number + ".rom", 16*1024, crcs[1]);
 
 			// fetch and verify the ROMs
-			const auto roms = rom_fetcher("AmstradCPC", required_roms);
+			const auto roms = rom_fetcher(required_roms);
 
 			for(std::size_t index = 0; index < roms.size(); ++index) {
 				auto &data = roms[index];

Machines/Apple/AppleII/AppleII.cpp

@@ -8,33 +8,34 @@
 
 #include "AppleII.hpp"
 
-#include "../../Activity/Source.hpp"
-#include "../MediaTarget.hpp"
-#include "../CRTMachine.hpp"
-#include "../JoystickMachine.hpp"
-#include "../KeyboardMachine.hpp"
-#include "../Utility/MemoryFuzzer.hpp"
-#include "../Utility/StringSerialiser.hpp"
+#include "../../../Activity/Source.hpp"
+#include "../../MediaTarget.hpp"
+#include "../../CRTMachine.hpp"
+#include "../../JoystickMachine.hpp"
+#include "../../KeyboardMachine.hpp"
+#include "../../Utility/MemoryFuzzer.hpp"
+#include "../../Utility/StringSerialiser.hpp"
 
-#include "../../Processors/6502/6502.hpp"
-#include "../../Components/AudioToggle/AudioToggle.hpp"
+#include "../../../Processors/6502/6502.hpp"
+#include "../../../Components/AudioToggle/AudioToggle.hpp"
 
-#include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
-#include "../../Outputs/Log.hpp"
+#include "../../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
+#include "../../../Outputs/Log.hpp"
 
 #include "Card.hpp"
 #include "DiskIICard.hpp"
 #include "Video.hpp"
 
-#include "../../Analyser/Static/AppleII/Target.hpp"
-#include "../../ClockReceiver/ForceInline.hpp"
-#include "../../Configurable/StandardOptions.hpp"
+#include "../../../Analyser/Static/AppleII/Target.hpp"
+#include "../../../ClockReceiver/ForceInline.hpp"
+#include "../../../Configurable/StandardOptions.hpp"
 
 #include <algorithm>
 #include <array>
 #include <memory>
 
-namespace AppleII {
+namespace Apple {
+namespace II {
 
 std::vector<std::unique_ptr<Configurable::Option>> get_options() {
 	return Configurable::standard_options(
@@ -51,12 +52,12 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 	public CPU::MOS6502::BusHandler,
 	public Inputs::Keyboard,
 	public Configurable::Device,
-	public AppleII::Machine,
+	public Apple::II::Machine,
 	public Activity::Source,
 	public JoystickMachine::Machine,
-	public AppleII::Card::Delegate {
+	public Apple::II::Card::Delegate {
 	private:
-		struct VideoBusHandler : public AppleII::Video::BusHandler {
+		struct VideoBusHandler : public Apple::II::Video::BusHandler {
 			public:
 				VideoBusHandler(uint8_t *ram, uint8_t *aux_ram) : ram_(ram), aux_ram_(aux_ram) {}
 
@@ -71,12 +72,12 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 
 		CPU::MOS6502::Processor<(model == Analyser::Static::AppleII::Target::Model::EnhancedIIe) ? CPU::MOS6502::Personality::PSynertek65C02 : CPU::MOS6502::Personality::P6502, ConcreteMachine, false> m6502_;
 		VideoBusHandler video_bus_handler_;
-		AppleII::Video::Video<VideoBusHandler, is_iie()> video_;
+		Apple::II::Video::Video<VideoBusHandler, is_iie()> video_;
 		int cycles_into_current_line_ = 0;
 		Cycles cycles_since_video_update_;
 
 		void update_video() {
-			video_.run_for(cycles_since_video_update_.flush());
+			video_.run_for(cycles_since_video_update_.flush<Cycles>());
 		}
 		static const int audio_divider = 8;
 		void update_audio() {
@@ -109,28 +110,28 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 		Cycles cycles_since_audio_update_;
 
 		// MARK: - Cards
-		std::array<std::unique_ptr<AppleII::Card>, 7> cards_;
+		std::array<std::unique_ptr<Apple::II::Card>, 7> cards_;
 		Cycles cycles_since_card_update_;
-		std::vector<AppleII::Card *> every_cycle_cards_;
-		std::vector<AppleII::Card *> just_in_time_cards_;
+		std::vector<Apple::II::Card *> every_cycle_cards_;
+		std::vector<Apple::II::Card *> just_in_time_cards_;
 
 		int stretched_cycles_since_card_update_ = 0;
 
-		void install_card(std::size_t slot, AppleII::Card *card) {
+		void install_card(std::size_t slot, Apple::II::Card *card) {
 			assert(slot >= 1 && slot < 8);
 			cards_[slot - 1].reset(card);
 			card->set_delegate(this);
 			pick_card_messaging_group(card);
 		}
 
-		bool is_every_cycle_card(AppleII::Card *card) {
+		bool is_every_cycle_card(Apple::II::Card *card) {
 			return !card->get_select_constraints();
 		}
 
-		void pick_card_messaging_group(AppleII::Card *card) {
+		void pick_card_messaging_group(Apple::II::Card *card) {
 			const bool is_every_cycle = is_every_cycle_card(card);
-			std::vector<AppleII::Card *> &intended = is_every_cycle ? every_cycle_cards_ : just_in_time_cards_;
-			std::vector<AppleII::Card *> &undesired = is_every_cycle ? just_in_time_cards_ : every_cycle_cards_;
+			std::vector<Apple::II::Card *> &intended = is_every_cycle ? every_cycle_cards_ : just_in_time_cards_;
+			std::vector<Apple::II::Card *> &undesired = is_every_cycle ? just_in_time_cards_ : every_cycle_cards_;
 
 			if(std::find(intended.begin(), intended.end(), card) != intended.end()) return;
 			auto old_membership = std::find(undesired.begin(), undesired.end(), card);
@@ -138,12 +139,12 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 			intended.push_back(card);
 		}
 
-		void card_did_change_select_constraints(AppleII::Card *card) override {
+		void card_did_change_select_constraints(Apple::II::Card *card) override {
 			pick_card_messaging_group(card);
 		}
 
-		AppleII::DiskIICard *diskii_card() {
-			return dynamic_cast<AppleII::DiskIICard *>(cards_[5].get());
+		Apple::II::DiskIICard *diskii_card() {
+			return dynamic_cast<Apple::II::DiskIICard *>(cards_[5].get());
 		}
 
 		// MARK: - Memory Map.
@@ -346,30 +347,39 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 
 			// Pick the required ROMs.
 			using Target = Analyser::Static::AppleII::Target;
-			std::vector<std::string> rom_names;
+			const std::string machine_name = "AppleII";
+			std::vector<ROMMachine::ROM> rom_descriptions;
 			size_t rom_size = 12*1024;
 			switch(target.model) {
 				default:
-					rom_names.push_back("apple2-character.rom");
-					rom_names.push_back("apple2o.rom");
+					rom_descriptions.emplace_back(machine_name, "the basic Apple II character ROM", "apple2-character.rom", 2*1024, 0x64f415c6);
+					rom_descriptions.emplace_back(machine_name, "the original Apple II ROM", "apple2o.rom", 12*1024, 0xba210588);
 				break;
 				case Target::Model::IIplus:
-					rom_names.push_back("apple2-character.rom");
-					rom_names.push_back("apple2.rom");
+					rom_descriptions.emplace_back(machine_name, "the basic Apple II character ROM", "apple2-character.rom", 2*1024, 0x64f415c6);
+					rom_descriptions.emplace_back(machine_name, "the Apple II+ ROM", "apple2.rom", 12*1024, 0xf66f9c26);
 				break;
 				case Target::Model::IIe:
 					rom_size += 3840;
-					rom_names.push_back("apple2eu-character.rom");
-					rom_names.push_back("apple2eu.rom");
+					rom_descriptions.emplace_back(machine_name, "the Apple IIe character ROM", "apple2eu-character.rom", 4*1024, 0x816a86f1);
+					rom_descriptions.emplace_back(machine_name, "the Apple IIe ROM", "apple2eu.rom", 32*1024, 0xe12be18d);
 				break;
 				case Target::Model::EnhancedIIe:
 					rom_size += 3840;
-					rom_names.push_back("apple2e-character.rom");
-					rom_names.push_back("apple2e.rom");
+					rom_descriptions.emplace_back(machine_name, "the Enhanced Apple IIe character ROM", "apple2e-character.rom", 4*1024, 0x2651014d);
+					rom_descriptions.emplace_back(machine_name, "the Enhanced Apple IIe ROM", "apple2e.rom", 32*1024, 0x65989942);
 				break;
 			}
-			const auto roms = rom_fetcher("AppleII", rom_names);
+			const auto roms = rom_fetcher(rom_descriptions);
 
+			// Try to install a Disk II card now, before checking the ROM list,
+			// to make sure that Disk II dependencies have been communicated.
+			if(target.disk_controller != Target::DiskController::None) {
+				// Apple recommended slot 6 for the (first) Disk II.
+				install_card(6, new Apple::II::DiskIICard(rom_fetcher, target.disk_controller == Target::DiskController::SixteenSector));
+			}
+
+			// Now, check and move the ROMs.
 			if(!roms[0] || !roms[1]) {
 				throw ROMMachine::Error::MissingROMs;
 			}
@@ -381,11 +391,6 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 
 			video_.set_character_rom(*roms[0]);
 
-			if(target.disk_controller != Target::DiskController::None) {
-				// Apple recommended slot 6 for the (first) Disk II.
-				install_card(6, new AppleII::DiskIICard(rom_fetcher, target.disk_controller == Target::DiskController::SixteenSector));
-			}
-
 			// Set up the default memory blocks. On a II or II+ these values will never change.
 			// On a IIe they'll be affected by selection of auxiliary RAM.
 			set_main_paging();
@@ -700,7 +705,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 					// If this is a card access, figure out which card is at play before determining
 					// the totality of who needs messaging.
 					size_t card_number = 0;
-					AppleII::Card::Select select = AppleII::Card::None;
+					Apple::II::Card::Select select = Apple::II::Card::None;
 
 					if(address >= 0xc100) {
 						/*
@@ -708,20 +713,20 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 								0xCn00 to 0xCnff: card n.
 						*/
 						card_number = (address - 0xc100) >> 8;
-						select = AppleII::Card::Device;
+						select = Apple::II::Card::Device;
 					} else {
 						/*
 							Decode the area conventionally used by cards for registers:
 								C0n0 to C0nF: card n - 8.
 						*/
 						card_number = (address - 0xc090) >> 4;
-						select = AppleII::Card::IO;
+						select = Apple::II::Card::IO;
 					}
 
 					// If the selected card is a just-in-time card, update the just-in-time cards,
 					// and then message it specifically.
 					const bool is_read = isReadOperation(operation);
-					AppleII::Card *const target = cards_[static_cast<size_t>(card_number)].get();
+					Apple::II::Card *const target = cards_[static_cast<size_t>(card_number)].get();
 					if(target && !is_every_cycle_card(target)) {
 						update_just_in_time_cards();
 						target->perform_bus_operation(select, is_read, address, value);
@@ -732,7 +737,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 					for(const auto &card: every_cycle_cards_) {
 						card->run_for(Cycles(1), is_stretched_cycle);
 						card->perform_bus_operation(
-							(card == target) ? select : AppleII::Card::None,
+							(card == target) ? select : Apple::II::Card::None,
 							is_read, address, value);
 					}
 					has_updated_cards = true;
@@ -744,7 +749,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 				const bool is_read = isReadOperation(operation);
 				for(const auto &card: every_cycle_cards_) {
 					card->run_for(Cycles(1), is_stretched_cycle);
-					card->perform_bus_operation(AppleII::Card::None, is_read, address, value);
+					card->perform_bus_operation(Apple::II::Card::None, is_read, address, value);
 				}
 			}
 
@@ -818,7 +823,7 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 
 		// MARK:: Configuration options.
 		std::vector<std::unique_ptr<Configurable::Option>> get_options() override {
-			return AppleII::get_options();
+			return Apple::II::get_options();
 		}
 
 		void set_selections(const Configurable::SelectionSet &selections_by_option) override {
@@ -860,9 +865,10 @@ template <Analyser::Static::AppleII::Target::Model model> class ConcreteMachine:
 		}
 };
 
+}
 }
 
-using namespace AppleII;
+using namespace Apple::II;
 
 Machine *Machine::AppleII(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
 	using Target = Analyser::Static::AppleII::Target;

Machines/Apple/AppleII/AppleII.hpp

@@ -9,14 +9,15 @@
 #ifndef AppleII_hpp
 #define AppleII_hpp
 
-#include "../../Configurable/Configurable.hpp"
-#include "../../Analyser/Static/StaticAnalyser.hpp"
-#include "../ROMMachine.hpp"
+#include "../../../Configurable/Configurable.hpp"
+#include "../../../Analyser/Static/StaticAnalyser.hpp"
+#include "../../ROMMachine.hpp"
 
 #include <memory>
 #include <vector>
 
-namespace AppleII {
+namespace Apple {
+namespace II {
 
 /// @returns The options available for an Apple II.
 std::vector<std::unique_ptr<Configurable::Option>> get_options();
@@ -29,6 +30,7 @@ class Machine {
 		static Machine *AppleII(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher);
 };
 
-};
+}
+}
 
 #endif /* AppleII_hpp */

Machines/Apple/AppleII/Card.hpp

@@ -9,11 +9,12 @@
 #ifndef Card_h
 #define Card_h
 
-#include "../../Processors/6502/6502.hpp"
-#include "../../ClockReceiver/ClockReceiver.hpp"
-#include "../../Activity/Observer.hpp"
+#include "../../../Processors/6502/6502.hpp"
+#include "../../../ClockReceiver/ClockReceiver.hpp"
+#include "../../../Activity/Observer.hpp"
 
-namespace AppleII {
+namespace Apple {
+namespace II {
 
 /*!
 	This provides a small subset of the interface offered to cards installed in
@@ -109,6 +110,7 @@ class Card {
 		}
 };
 
+}
 }
 
 #endif /* Card_h */

Machines/Apple/AppleII/DiskIICard.cpp

@@ -8,15 +8,25 @@
 
 #include "DiskIICard.hpp"
 
-using namespace AppleII;
+using namespace Apple::II;
 
 DiskIICard::DiskIICard(const ROMMachine::ROMFetcher &rom_fetcher, bool is_16_sector) : diskii_(2045454) {
-	const auto roms = rom_fetcher(
-		"DiskII",
-		{
-			is_16_sector ? "boot-16.rom" : "boot-13.rom",
-			is_16_sector ? "state-machine-16.rom" : "state-machine-13.rom"
+	std::vector<std::unique_ptr<std::vector<uint8_t>>> roms;
+	if(is_16_sector) {
+		roms = rom_fetcher({
+			{"DiskII", "the Disk II 16-sector boot ROM", "boot-16.rom", 256, 0xce7144f6},
+			{"DiskII", "the Disk II 16-sector state machine ROM", "state-machine-16.rom", 256, { 0x9796a238, 0xb72a2c70 } }
 		});
+	} else {
+		roms = rom_fetcher({
+			{"DiskII", "the Disk II 13-sector boot ROM", "boot-13.rom", 256, 0xd34eb2ff},
+			{"DiskII", "the Disk II 13-sector state machine ROM", "state-machine-13.rom", 256, 0x62e22620 }
+		});
+	}
+	if(!roms[0] || !roms[1]) {
+		throw ROMMachine::Error::MissingROMs;
+	}
+
 	boot_ = std::move(*roms[0]);
 	diskii_.set_state_machine(*roms[1]);
 	set_select_constraints(None);

Machines/Apple/AppleII/DiskIICard.hpp

@@ -10,17 +10,18 @@
 #define DiskIICard_hpp
 
 #include "Card.hpp"
-#include "../ROMMachine.hpp"
+#include "../../ROMMachine.hpp"
 
-#include "../../Components/DiskII/DiskII.hpp"
-#include "../../Storage/Disk/Disk.hpp"
-#include "../../ClockReceiver/ClockingHintSource.hpp"
+#include "../../../Components/DiskII/DiskII.hpp"
+#include "../../../Storage/Disk/Disk.hpp"
+#include "../../../ClockReceiver/ClockingHintSource.hpp"
 
 #include <cstdint>
 #include <memory>
 #include <vector>
 
-namespace AppleII {
+namespace Apple {
+namespace II {
 
 class DiskIICard: public Card, public ClockingHint::Observer {
 	public:
@@ -41,6 +42,7 @@ class DiskIICard: public Card, public ClockingHint::Observer {
 		ClockingHint::Preference diskii_clocking_preference_ = ClockingHint::Preference::RealTime;
 };
 
+}
 }
 
 #endif /* DiskIICard_hpp */

Machines/Apple/AppleII/Video.cpp

@@ -8,7 +8,7 @@
 
 #include "Video.hpp"
 
-using namespace AppleII::Video;
+using namespace Apple::II::Video;
 
 VideoBase::VideoBase(bool is_iie, std::function<void(Cycles)> &&target) :
 	crt_(910, 1, Outputs::Display::Type::NTSC60, Outputs::Display::InputDataType::Luminance1),

Machines/Apple/AppleII/Video.hpp

@@ -9,14 +9,15 @@
 #ifndef Video_hpp
 #define Video_hpp
 
-#include "../../Outputs/CRT/CRT.hpp"
-#include "../../ClockReceiver/ClockReceiver.hpp"
-#include "../../ClockReceiver/ClockDeferrer.hpp"
+#include "../../../Outputs/CRT/CRT.hpp"
+#include "../../../ClockReceiver/ClockReceiver.hpp"
+#include "../../../ClockReceiver/DeferredQueue.hpp"
 
 #include <array>
 #include <vector>
 
-namespace AppleII {
+namespace Apple {
+namespace II {
 namespace Video {
 
 class BusHandler {
@@ -250,8 +251,8 @@ class VideoBase {
 		*/
 		void output_fat_low_resolution(uint8_t *target, const uint8_t *source, size_t length, int column, int row) const;
 
-		// Maintain a ClockDeferrer for delayed mode switches.
-		ClockDeferrer<Cycles> deferrer_;
+		// Maintain a DeferredQueue for delayed mode switches.
+		DeferredQueue<Cycles> deferrer_;
 };
 
 template <class BusHandler, bool is_iie> class Video: public VideoBase {
@@ -600,6 +601,7 @@ template <class BusHandler, bool is_iie> class Video: public VideoBase {
 		BusHandler &bus_handler_;
 };
 
+}
 }
 }
 

Machines/Apple/Macintosh/Audio.cpp

@@ -0,0 +1,97 @@
+//
+//  Audio.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 31/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "Audio.hpp"
+
+using namespace Apple::Macintosh;
+
+namespace {
+
+// The sample_length is coupled with the clock rate selected within the Macintosh proper;
+// as per the header-declaration a divide-by-two clock is expected to arrive here.
+const std::size_t sample_length = 352 / 2;
+
+}
+
+Audio::Audio(Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_(task_queue) {}
+
+// MARK: - Inputs
+
+void Audio::post_sample(uint8_t sample) {
+	// Store sample directly indexed by current write pointer; this ensures that collected samples
+	// directly map to volume and enabled/disabled states.
+	sample_queue_.buffer[sample_queue_.write_pointer] = sample;
+	sample_queue_.write_pointer = (sample_queue_.write_pointer + 1) % sample_queue_.buffer.size();
+}
+
+void Audio::set_volume(int volume) {
+	// Do nothing if the volume hasn't changed.
+	if(posted_volume_ == volume) return;
+	posted_volume_ = volume;
+
+	// Post the volume change as a deferred event.
+	task_queue_.defer([=] () {
+		volume_ = volume;
+		set_volume_multiplier();
+	});
+}
+
+void Audio::set_enabled(bool on) {
+	// Do nothing if the mask hasn't changed.
+	if(posted_enable_mask_ == int(on)) return;
+	posted_enable_mask_ = int(on);
+
+	// Post the enabled mask change as a deferred event.
+	task_queue_.defer([=] () {
+		enabled_mask_ = int(on);
+		set_volume_multiplier();
+	});
+}
+
+// MARK: - Output generation
+
+bool Audio::is_zero_level() {
+	return !volume_ || !enabled_mask_;
+}
+
+void Audio::set_sample_volume_range(std::int16_t range) {
+	// Some underflow here doesn't really matter.
+	output_volume_ = range / (7 * 255);
+	set_volume_multiplier();
+}
+
+void Audio::set_volume_multiplier() {
+	volume_multiplier_ = int16_t(output_volume_ * volume_ * enabled_mask_);
+}
+
+void Audio::get_samples(std::size_t number_of_samples, int16_t *target) {
+	// TODO: the implementation below acts as if the hardware uses pulse-amplitude modulation;
+	// in fact it uses pulse-width modulation. But the scale for pulses isn't specified, so
+	// that's something to return to.
+
+	while(number_of_samples) {
+		// Determine how many output samples will be at the same level.
+		const auto cycles_left_in_sample = std::min(number_of_samples, sample_length - subcycle_offset_);
+
+		// Determine the output level, and output that many samples.
+		// (Hoping that the copiler substitutes an effective memset16-type operation here).
+		const int16_t output_level = volume_multiplier_ * (int16_t(sample_queue_.buffer[sample_queue_.read_pointer]) - 128);
+		for(size_t c = 0; c < cycles_left_in_sample; ++c) {
+			target[c] = output_level;
+		}
+		target += cycles_left_in_sample;
+
+		// Advance the sample pointer.
+		subcycle_offset_ += cycles_left_in_sample;
+		sample_queue_.read_pointer = (sample_queue_.read_pointer + (subcycle_offset_ / sample_length)) % sample_queue_.buffer.size();
+		subcycle_offset_ %= sample_length;
+
+		// Decreate the number of samples left to write.
+		number_of_samples -= cycles_left_in_sample;
+	}
+}

Machines/Apple/Macintosh/Audio.hpp

@@ -0,0 +1,88 @@
+//
+//  Audio.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 31/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef Audio_hpp
+#define Audio_hpp
+
+#include "../../../Concurrency/AsyncTaskQueue.hpp"
+#include "../../../ClockReceiver/ClockReceiver.hpp"
+#include "../../../Outputs/Speaker/Implementation/SampleSource.hpp"
+
+#include <array>
+#include <atomic>
+
+namespace Apple {
+namespace Macintosh {
+
+/*!
+	Implements the Macintosh's audio output hardware.
+
+	Designed to be clocked at half the rate of the real hardware — i.e.
+	a shade less than 4Mhz.
+*/
+class Audio: public ::Outputs::Speaker::SampleSource {
+	public:
+		Audio(Concurrency::DeferringAsyncTaskQueue &task_queue);
+
+		/*!
+			Macintosh audio is (partly) sourced by the same scanning
+			hardware as the video; each line it collects an additional
+			word of memory, half of which is used for audio output.
+
+			Use this method to add a newly-collected sample to the queue.
+		*/
+		void post_sample(uint8_t sample);
+
+		/*!
+			Macintosh audio also separately receives an output volume
+			level, in the range 0 to 7.
+
+			Use this method to set the current output volume.
+		*/
+		void set_volume(int volume);
+
+		/*!
+			A further factor in audio output is the on-off toggle.
+		*/
+		void set_enabled(bool on);
+
+		// to satisfy ::Outputs::Speaker (included via ::Outputs::Filter.
+		void get_samples(std::size_t number_of_samples, int16_t *target);
+		bool is_zero_level();
+		void set_sample_volume_range(std::int16_t range);
+
+	private:
+		Concurrency::DeferringAsyncTaskQueue &task_queue_;
+
+		// A queue of fetched samples; read from by one thread,
+		// written to by another.
+		struct {
+			std::array<uint8_t, 740> buffer;
+			size_t read_pointer = 0, write_pointer = 0;
+		} sample_queue_;
+
+		// Emulator-thread stateful variables, to avoid work posting
+		// deferral updates if possible.
+		int posted_volume_ = 0;
+		int posted_enable_mask_ = 0;
+
+		// Stateful variables, modified from the audio generation
+		// thread only.
+		int volume_ = 0;
+		int enabled_mask_ = 0;
+		std::int16_t output_volume_ = 0;
+
+		std::int16_t volume_multiplier_ = 0;
+		std::size_t subcycle_offset_ = 0;
+		void set_volume_multiplier();
+};
+
+}
+}
+
+#endif /* Audio_hpp */

Machines/Apple/Macintosh/DeferredAudio.hpp

@@ -0,0 +1,34 @@
+//
+//  DeferredAudio.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 01/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef DeferredAudio_h
+#define DeferredAudio_h
+
+#include "Audio.hpp"
+#include "../../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
+
+namespace Apple {
+namespace Macintosh {
+
+struct DeferredAudio {
+	Concurrency::DeferringAsyncTaskQueue queue;
+	Audio audio;
+	Outputs::Speaker::LowpassSpeaker<Audio> speaker;
+	HalfCycles time_since_update;
+
+	DeferredAudio() : audio(queue), speaker(audio) {}
+
+	void flush() {
+		speaker.run_for(queue, time_since_update.flush<Cycles>());
+	}
+};
+
+}
+}
+
+#endif /* DeferredAudio_h */

Machines/Apple/Macintosh/DriveSpeedAccumulator.cpp

@@ -0,0 +1,63 @@
+//
+//  DriveSpeedAccumulator.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 01/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "DriveSpeedAccumulator.hpp"
+
+using namespace Apple::Macintosh;
+
+void DriveSpeedAccumulator::post_sample(uint8_t sample) {
+	if(!number_of_drives_) return;
+
+	// An Euler-esque approximation is used here: just collect all
+	// the samples until there is a certain small quantity of them,
+	// then produce a new estimate of rotation speed and start the
+	// buffer afresh.
+	samples_[sample_pointer_] = sample;
+	++sample_pointer_;
+
+	if(sample_pointer_ == samples_.size()) {
+		sample_pointer_ = 0;
+
+		// The below fits for a function like `a + bc`; it encapsultes the following
+		// beliefs:
+		//
+		//	(i) motor speed is proportional to voltage supplied;
+		//	(ii) with pulse-width modulation it's therefore proportional to the duty cycle;
+		//	(iii) the Mac pulse-width modulates whatever it reads from the disk speed buffer;
+		//	(iv) ... subject to software pulse-width modulation of that pulse-width modulation.
+		//
+		// So, I believe current motor speed is proportional to a low-pass filtering of
+		// the speed buffer. Which I've implemented very coarsely via 'large' bucketed-averages,
+		// noting also that exact disk motor speed is always a little approximate.
+
+		// Sum all samples.
+		// TODO: if the above is the correct test, do it on sample receipt rather than
+		// bothering with an intermediate buffer.
+		int sum = 0;
+		for(auto s: samples_) {
+			sum += s;
+		}
+
+		// The formula below was derived from observing values the Mac wrote into its
+		// disk-speed buffer. Given that it runs a calibration loop before doing so,
+		// I cannot guarantee the accuracy of these numbers beyond being within the
+		// range that the computer would accept.
+		const float normalised_sum = float(sum) / float(samples_.size());
+		const float rotation_speed = (normalised_sum * 27.08f) - 259.0f;
+
+		for(int c = 0; c < number_of_drives_; ++c) {
+			drives_[c]->set_rotation_speed(rotation_speed);
+		}
+//		printf("RPM: %0.2f (%d sum)\n", rotation_speed, sum);
+	}
+}
+
+void DriveSpeedAccumulator::add_drive(Apple::Macintosh::DoubleDensityDrive *drive) {
+	drives_[number_of_drives_] = drive;
+	++number_of_drives_;
+}

Machines/Apple/Macintosh/DriveSpeedAccumulator.hpp

@@ -0,0 +1,45 @@
+//
+//  DriveSpeedAccumulator.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 01/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef DriveSpeedAccumulator_hpp
+#define DriveSpeedAccumulator_hpp
+
+#include <array>
+#include <cstddef>
+#include <cstdint>
+
+#include "../../../Components/DiskII/MacintoshDoubleDensityDrive.hpp"
+
+namespace Apple {
+namespace Macintosh {
+
+class DriveSpeedAccumulator {
+	public:
+		/*!
+			Accepts fetched motor control values.
+		*/
+		void post_sample(uint8_t sample);
+
+		/*!
+			Adds a connected drive. Up to two of these
+			can be supplied. Only Macintosh DoubleDensityDrives
+			are supported.
+		*/
+		void add_drive(Apple::Macintosh::DoubleDensityDrive *drive);
+
+	private:
+		std::array<uint8_t, 20> samples_;
+		std::size_t sample_pointer_ = 0;
+		Apple::Macintosh::DoubleDensityDrive *drives_[2] = {nullptr, nullptr};
+		int number_of_drives_ = 0;
+};
+
+}
+}
+
+#endif /* DriveSpeedAccumulator_hpp */

Machines/Apple/Macintosh/Keyboard.hpp

@@ -0,0 +1,294 @@
+//
+//  Keyboard.h
+//  Clock Signal
+//
+//  Created by Thomas Harte on 08/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef Apple_Macintosh_Keyboard_hpp
+#define Apple_Macintosh_Keyboard_hpp
+
+#include "../../KeyboardMachine.hpp"
+
+#include <mutex>
+#include <vector>
+
+namespace Apple {
+namespace Macintosh {
+
+class Keyboard {
+	public:
+		void set_input(bool data) {
+			switch(mode_) {
+				case Mode::Waiting:
+					/*
+						"Only the computer can initiate communication over the keyboard lines. When the computer and keyboard
+						are turned on, the computer is in charge of the keyboard interface and the keyboard is passive. The
+						computer signals that it is ready to begin communication by pulling the Keyboard Data line low."
+					*/
+					if(!data) {
+						mode_ = Mode::AcceptingCommand;
+						phase_ = 0;
+						command_ = 0;
+					}
+				break;
+
+				case Mode::AcceptingCommand:
+					/* Note value, so that it can be latched upon a clock transition. */
+					data_input_ = data;
+				break;
+
+				case Mode::AwaitingEndOfCommand:
+					/*
+						The last bit of the command leaves the Keyboard Data line low; the computer then indicates that it is ready
+						to receive the keyboard's response by setting the Keyboard Data line high.
+					*/
+					if(data) {
+						mode_ = Mode::PerformingCommand;
+						phase_ = 0;
+					}
+				break;
+
+				default:
+				case Mode::SendingResponse:
+					/* This line isn't currently an input; do nothing. */
+				break;
+			}
+		}
+
+		bool get_clock() {
+			return clock_output_;
+		}
+
+		bool get_data() {
+			return !!(response_ & 0x80);
+		}
+
+		/*!
+			The keyboard expects ~10 µs-frequency ticks, i.e. a clock rate of just around 100 kHz.
+		*/
+		void run_for(HalfCycles cycle) {
+			switch(mode_) {
+				default:
+				case Mode::Waiting: return;
+
+				case Mode::AcceptingCommand: {
+					/*
+						"When the computer is sending data to the keyboard, the keyboard transmits eight cycles of 400 µS each (180 µS low,
+						220 µS high) on the Keyboard Clock line. On the falling edge of each keyboard clock cycle, the Macintosh Plus places
+						a data bit on the data line and holds it there for 400 µS. The keyboard reads the data bit 80 µS after the rising edge
+						of the Keyboard Clock signal."
+					*/
+					const auto offset = phase_ % 40;
+					clock_output_ = offset >= 18;
+
+					if(offset == 26) {
+						command_ = (command_ << 1) | (data_input_ ? 1 : 0);
+					}
+
+					++phase_;
+					if(phase_ == 8*40) {
+						mode_ = Mode::AwaitingEndOfCommand;
+						phase_ = 0;
+						clock_output_ = false;
+					}
+				} break;
+
+				case Mode::AwaitingEndOfCommand:
+					// Time out if the end-of-command seems not to be forthcoming.
+					// This is an elaboration on my part; a guess.
+					++phase_;
+					if(phase_ == 1000) {
+						clock_output_ = false;
+						mode_ = Mode::Waiting;
+						phase_ = 0;
+					}
+				return;
+
+				case Mode::PerformingCommand: {
+					response_ = perform_command(command_);
+
+					// Inquiry has a 0.25-second timeout; everything else is instant.
+					++phase_;
+					if(phase_ == 25000 || command_ != 0x10 || response_ != 0x7b) {
+						mode_ = Mode::SendingResponse;
+						phase_ = 0;
+					}
+				} break;
+
+				case Mode::SendingResponse: {
+					/*
+						"When sending data to the computer, the keyboard transmits eight cycles of 330 µS each (160 µS low, 170 µS high)
+						on the normally high Keyboard Clock line. It places a data bit on the data line 40 µS before the falling edge of each
+						clock cycle and maintains it for 330 µS. The VIA in the computer latches the data bit into its shift register on the
+						rising edge of the Keyboard Clock signal."
+					*/
+					const auto offset = phase_ % 33;
+					clock_output_ = offset >= 16;
+
+					if(offset == 29) {
+						response_ <<= 1;
+					}
+
+					++phase_;
+					if(phase_ == 8*33) {
+						clock_output_ = false;
+						mode_ = Mode::Waiting;
+						phase_ = 0;
+					}
+				} break;
+			}
+		}
+
+		void enqueue_key_state(uint16_t key, bool is_pressed) {
+			// Front insert; messages will be pop_back'd.
+			std::lock_guard<decltype(key_queue_mutex_)> lock(key_queue_mutex_);
+
+			// Keys on the keypad are preceded by a $79 keycode; in the internal naming scheme
+			// they are indicated by having bit 8 set. So add the $79 prefix if required.
+			if(key & 0x100) {
+				key_queue_.insert(key_queue_.begin(), 0x79);
+			}
+			key_queue_.insert(key_queue_.begin(), (is_pressed ? 0x00 : 0x80) | uint8_t(key));
+		}
+
+	private:
+
+		int perform_command(int command) {
+			switch(command) {
+				case 0x10:		// Inquiry.
+				case 0x14: {	// Instant.
+					std::lock_guard<decltype(key_queue_mutex_)> lock(key_queue_mutex_);
+					if(!key_queue_.empty()) {
+						const auto new_message = key_queue_.back();
+						key_queue_.pop_back();
+						return new_message;
+					}
+				} break;
+
+				case 0x16:	// Model number.
+				return
+					0x01 |			// b0: always 1
+					(1 << 1) |		// keyboard model number
+					(1 << 4);		// next device number
+									// (b7 not set => no next device)
+
+				case 0x36:	// Test
+				return 0x7d;		// 0x7d = ACK, 0x77 = not ACK.
+			}
+			return 0x7b;	// No key transition.
+		}
+
+		enum class Mode {
+			Waiting,
+			AcceptingCommand,
+			AwaitingEndOfCommand,
+			SendingResponse,
+			PerformingCommand
+		} mode_ = Mode::Waiting;
+		int phase_ = 0;
+		int command_ = 0;
+		int response_ = 0;
+
+		bool data_input_ = false;
+		bool clock_output_ = false;
+
+		// TODO: improve this very, very simple implementation.
+		std::mutex key_queue_mutex_;
+		std::vector<uint8_t> key_queue_;
+};
+
+/*!
+	Provides a mapping from idiomatic PC keys to Macintosh keys.
+*/
+class KeyboardMapper: public KeyboardMachine::MappedMachine::KeyboardMapper {
+	uint16_t mapped_key_for_key(Inputs::Keyboard::Key key) override {
+		using Key = Inputs::Keyboard::Key;
+		switch(key) {
+			default: return KeyboardMachine::MappedMachine::KeyNotMapped;
+
+			/*
+				See p284 of the Apple Guide to the Macintosh Family Hardware
+				for documentation of the mapping below.
+			*/
+
+			case Key::BackTick:				return 0x65;
+			case Key::k1:					return 0x25;
+			case Key::k2:					return 0x27;
+			case Key::k3:					return 0x29;
+			case Key::k4:					return 0x2b;
+			case Key::k5:					return 0x2f;
+			case Key::k6:					return 0x2d;
+			case Key::k7:					return 0x35;
+			case Key::k8:					return 0x39;
+			case Key::k9:					return 0x33;
+			case Key::k0:					return 0x3b;
+			case Key::Hyphen:				return 0x37;
+			case Key::Equals:				return 0x31;
+			case Key::BackSpace:			return 0x67;
+
+			case Key::Tab:					return 0x61;
+			case Key::Q:					return 0x19;
+			case Key::W:					return 0x1b;
+			case Key::E:					return 0x1d;
+			case Key::R:					return 0x1f;
+			case Key::T:					return 0x23;
+			case Key::Y:					return 0x21;
+			case Key::U:					return 0x41;
+			case Key::I:					return 0x45;
+			case Key::O:					return 0x3f;
+			case Key::P:					return 0x47;
+			case Key::OpenSquareBracket:	return 0x43;
+			case Key::CloseSquareBracket:	return 0x3d;
+
+			case Key::CapsLock:				return 0x73;
+			case Key::A:					return 0x01;
+			case Key::S:					return 0x03;
+			case Key::D:					return 0x05;
+			case Key::F:					return 0x07;
+			case Key::G:					return 0x0b;
+			case Key::H:					return 0x09;
+			case Key::J:					return 0x4d;
+			case Key::K:					return 0x51;
+			case Key::L:					return 0x4b;
+			case Key::Semicolon:			return 0x53;
+			case Key::Quote:				return 0x4f;
+			case Key::Enter:				return 0x49;
+
+			case Key::LeftShift:			return 0x71;
+			case Key::Z:					return 0x0d;
+			case Key::X:					return 0x0f;
+			case Key::C:					return 0x11;
+			case Key::V:					return 0x13;
+			case Key::B:					return 0x17;
+			case Key::N:					return 0x5b;
+			case Key::M:					return 0x5d;
+			case Key::Comma:				return 0x57;
+			case Key::FullStop:				return 0x5f;
+			case Key::ForwardSlash:			return 0x59;
+			case Key::RightShift:			return 0x71;
+
+			case Key::Left:					return 0x100 | 0x0d;
+			case Key::Right:				return 0x100 | 0x05;
+			case Key::Up:					return 0x100 | 0x1b;
+			case Key::Down:					return 0x100 | 0x11;
+
+			case Key::LeftOption:
+			case Key::RightOption:			return 0x75;
+			case Key::LeftMeta:
+			case Key::RightMeta:			return 0x6f;
+
+			case Key::Space:				return 0x63;
+			case Key::BackSlash:			return 0x55;
+
+			/* TODO: the numeric keypad. */
+		}
+	}
+
+};
+
+}
+}
+
+#endif /* Apple_Macintosh_Keyboard_hpp */

Machines/Apple/Macintosh/Macintosh.cpp

@@ -0,0 +1,653 @@
+//
+//  Macintosh.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 03/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "Macintosh.hpp"
+
+#include <array>
+
+#include "DeferredAudio.hpp"
+#include "DriveSpeedAccumulator.hpp"
+#include "Keyboard.hpp"
+#include "RealTimeClock.hpp"
+#include "Video.hpp"
+
+#include "../../CRTMachine.hpp"
+#include "../../KeyboardMachine.hpp"
+#include "../../MediaTarget.hpp"
+#include "../../MouseMachine.hpp"
+
+#include "../../../Inputs/QuadratureMouse/QuadratureMouse.hpp"
+#include "../../../Outputs/Log.hpp"
+
+#include "../../../ClockReceiver/JustInTime.hpp"
+
+//#define LOG_TRACE
+
+#include "../../../Components/6522/6522.hpp"
+#include "../../../Components/8530/z8530.hpp"
+#include "../../../Components/DiskII/IWM.hpp"
+#include "../../../Components/DiskII/MacintoshDoubleDensityDrive.hpp"
+#include "../../../Processors/68000/68000.hpp"
+
+#include "../../../Analyser/Static/Macintosh/Target.hpp"
+
+#include "../../Utility/MemoryPacker.hpp"
+#include "../../Utility/MemoryFuzzer.hpp"
+
+namespace {
+
+const int CLOCK_RATE = 7833600;
+
+}
+
+namespace Apple {
+namespace Macintosh {
+
+template <Analyser::Static::Macintosh::Target::Model model> class ConcreteMachine:
+	public Machine,
+	public CRTMachine::Machine,
+	public MediaTarget::Machine,
+	public MouseMachine::Machine,
+	public CPU::MC68000::BusHandler,
+	public KeyboardMachine::MappedMachine,
+	public Zilog::SCC::z8530::Delegate {
+	public:
+		using Target = Analyser::Static::Macintosh::Target;
+
+		ConcreteMachine(const Target &target, const ROMMachine::ROMFetcher &rom_fetcher) :
+		 	mc68000_(*this),
+		 	iwm_(CLOCK_RATE),
+		 	video_(ram_, audio_, drive_speed_accumulator_),
+		 	via_(via_port_handler_),
+		 	via_port_handler_(*this, clock_, keyboard_, video_, audio_, iwm_, mouse_),
+		 	drives_{
+		 		{CLOCK_RATE, model >= Analyser::Static::Macintosh::Target::Model::Mac512ke},
+		 		{CLOCK_RATE, model >= Analyser::Static::Macintosh::Target::Model::Mac512ke}
+			},
+			mouse_(1) {
+
+			// Select a ROM name and determine the proper ROM and RAM sizes
+			// based on the machine model.
+			using Model = Analyser::Static::Macintosh::Target::Model;
+			const std::string machine_name = "Macintosh";
+			uint32_t ram_size, rom_size;
+			std::vector<ROMMachine::ROM> rom_descriptions;
+			switch(model) {
+				default:
+				case Model::Mac128k:
+					ram_size = 128*1024;
+					rom_size = 64*1024;
+					rom_descriptions.emplace_back(machine_name, "the Macintosh 128k ROM", "mac128k.rom", 64*1024, 0x6d0c8a28);
+				break;
+				case Model::Mac512k:
+					ram_size = 512*1024;
+					rom_size = 64*1024;
+					rom_descriptions.emplace_back(machine_name, "the Macintosh 512k ROM", "mac512k.rom", 64*1024, 0xcf759e0d);
+				break;
+				case Model::Mac512ke:
+				case Model::MacPlus: {
+					ram_size = 512*1024;
+					rom_size = 128*1024;
+					const std::initializer_list<uint32_t> crc32s = { 0x4fa5b399, 0x7cacd18f, 0xb2102e8e };
+					rom_descriptions.emplace_back(machine_name, "the Macintosh Plus ROM", "macplus.rom", 128*1024, crc32s);
+				} break;
+			}
+			ram_mask_ = (ram_size >> 1) - 1;
+			rom_mask_ = (rom_size >> 1) - 1;
+			video_.set_ram_mask(ram_mask_);
+
+			// Grab a copy of the ROM and convert it into big-endian data.
+			const auto roms = rom_fetcher(rom_descriptions);
+			if(!roms[0]) {
+				throw ROMMachine::Error::MissingROMs;
+			}
+			roms[0]->resize(rom_size);
+			Memory::PackBigEndian16(*roms[0], rom_);
+
+			// Randomise memory contents.
+			Memory::Fuzz(ram_, sizeof(ram_) / sizeof(*ram_));
+
+			// Attach the drives to the IWM.
+			iwm_.iwm.set_drive(0, &drives_[0]);
+			iwm_.iwm.set_drive(1, &drives_[1]);
+
+			// If they are 400kb drives, also attach them to the drive-speed accumulator.
+			if(!drives_[0].is_800k()) drive_speed_accumulator_.add_drive(&drives_[0]);
+			if(!drives_[1].is_800k()) drive_speed_accumulator_.add_drive(&drives_[1]);
+
+			// Make sure interrupt changes from the SCC are observed.
+			scc_.set_delegate(this);
+
+			// The Mac runs at 7.8336mHz.
+			set_clock_rate(double(CLOCK_RATE));
+			audio_.speaker.set_input_rate(float(CLOCK_RATE) / 2.0f);
+
+			// Insert any supplied media.
+			insert_media(target.media);
+		}
+
+		~ConcreteMachine() {
+			audio_.queue.flush();
+		}
+
+		void set_scan_target(Outputs::Display::ScanTarget *scan_target) override {
+			video_.set_scan_target(scan_target);
+		}
+
+		Outputs::Speaker::Speaker *get_speaker() override {
+			return &audio_.speaker;
+		}
+
+		void run_for(const Cycles cycles) override {
+			mc68000_.run_for(cycles);
+		}
+
+		using Microcycle = CPU::MC68000::Microcycle;
+
+		HalfCycles perform_bus_operation(const Microcycle &cycle, int is_supervisor) {
+			// TODO: pick a delay if this is a video-clashing memory fetch.
+			HalfCycles delay(0);
+
+			time_since_video_update_ += cycle.length;
+			iwm_.time_since_update += cycle.length;
+
+			// The VIA runs at one-tenth of the 68000's clock speed, in sync with the E clock.
+			// See: Guide to the Macintosh Hardware Family p149 (PDF p188). Some extra division
+			// may occur here in order to provide VSYNC at a proper moment.
+			// Possibly route vsync.
+			if(time_since_video_update_ < time_until_video_event_) {
+				via_clock_ += cycle.length;
+				via_.run_for(via_clock_.divide(HalfCycles(10)));
+			} else {
+				auto via_time_base = time_since_video_update_ - cycle.length;
+				auto via_cycles_outstanding = cycle.length;
+				while(time_until_video_event_ < time_since_video_update_) {
+					const auto via_cycles = time_until_video_event_ - via_time_base;
+					via_time_base = HalfCycles(0);
+					via_cycles_outstanding -= via_cycles;
+
+					via_clock_ += via_cycles;
+					via_.run_for(via_clock_.divide(HalfCycles(10)));
+
+					video_.run_for(time_until_video_event_);
+					time_since_video_update_ -= time_until_video_event_;
+					time_until_video_event_ = video_.get_next_sequence_point();
+
+					via_.set_control_line_input(MOS::MOS6522::Port::A, MOS::MOS6522::Line::One, !video_.vsync());
+				}
+
+				via_clock_ += via_cycles_outstanding;
+				via_.run_for(via_clock_.divide(HalfCycles(10)));
+			}
+
+			// The keyboard also has a clock, albeit a very slow one — 100,000 cycles/second.
+			// Its clock and data lines are connected to the VIA.
+			keyboard_clock_ += cycle.length;
+			const auto keyboard_ticks = keyboard_clock_.divide(HalfCycles(CLOCK_RATE / 100000));
+			if(keyboard_ticks > HalfCycles(0)) {
+				keyboard_.run_for(keyboard_ticks);
+				via_.set_control_line_input(MOS::MOS6522::Port::B, MOS::MOS6522::Line::Two, keyboard_.get_data());
+				via_.set_control_line_input(MOS::MOS6522::Port::B, MOS::MOS6522::Line::One, keyboard_.get_clock());
+			}
+
+			// Feed mouse inputs within at most 1250 cycles of each other.
+			if(mouse_.has_steps()) {
+				time_since_mouse_update_ += cycle.length;
+				const auto mouse_ticks = time_since_mouse_update_.divide(HalfCycles(2500));
+				if(mouse_ticks > HalfCycles(0)) {
+					mouse_.prepare_step();
+					scc_.set_dcd(0, mouse_.get_channel(1) & 1);
+					scc_.set_dcd(1, mouse_.get_channel(0) & 1);
+				}
+			}
+
+			// TODO: SCC should be clocked at a divide-by-two, if and when it actually has
+			// anything connected.
+
+			// Consider updating the real-time clock.
+			real_time_clock_ += cycle.length;
+			auto ticks = real_time_clock_.divide_cycles(Cycles(CLOCK_RATE)).as_int();
+			while(ticks--) {
+				clock_.update();
+				// TODO: leave a delay between toggling the input rather than using this coupled hack.
+				via_.set_control_line_input(MOS::MOS6522::Port::A, MOS::MOS6522::Line::Two, true);
+				via_.set_control_line_input(MOS::MOS6522::Port::A, MOS::MOS6522::Line::Two, false);
+			}
+
+			// A null cycle leaves nothing else to do.
+			if(!(cycle.operation & (Microcycle::NewAddress | Microcycle::SameAddress))) return delay;
+
+			auto word_address = cycle.active_operation_word_address();
+
+			// Everything above E0 0000 is signalled as being on the peripheral bus.
+			mc68000_.set_is_peripheral_address(word_address >= 0x700000);
+
+			// All code below deals only with reads and writes — cycles in which a
+			// data select is active. So quit now if this is not the active part of
+			//  a read or write.
+			if(!cycle.data_select_active()) return delay;
+
+			// Check whether this access maps into the IO area; if so then
+			// apply more complicated decoding logic.
+			if(word_address >= 0x400000) {
+				const int register_address = word_address >> 8;
+
+				switch(word_address & 0x78f000) {
+					case 0x70f000:
+						// VIA accesses are via address 0xefe1fe + register*512,
+						// which at word precision is 0x77f0ff + register*256.
+						if(cycle.operation & Microcycle::Read) {
+							cycle.value->halves.low = via_.get_register(register_address);
+						} else {
+							via_.set_register(register_address, cycle.value->halves.low);
+						}
+					break;
+
+					case 0x68f000:
+						// The IWM; this is a purely polled device, so can be run on demand.
+						iwm_.flush();
+						if(cycle.operation & Microcycle::Read) {
+							cycle.value->halves.low = iwm_.iwm.read(register_address);
+						} else {
+							iwm_.iwm.write(register_address, cycle.value->halves.low);
+						}
+					break;
+
+					case 0x780000:
+						// Phase read.
+						if(cycle.operation & Microcycle::Read) {
+							cycle.value->halves.low = phase_ & 7;
+						}
+					break;
+
+					case 0x480000: case 0x48f000:
+					case 0x580000: case 0x58f000:
+						// Any word access here adjusts phase.
+						if(cycle.operation & Microcycle::SelectWord) {
+							++phase_;
+						} else {
+							if(word_address < 0x500000) {
+								// A0 = 1 => reset; A0 = 0 => read.
+								if(*cycle.address & 1) {
+									scc_.reset();
+								} else {
+									const auto read = scc_.read(int(word_address));
+									if(cycle.operation & Microcycle::Read) {
+										cycle.value->halves.low = read;
+									}
+								}
+							} else {
+								if(*cycle.address & 1) {
+									if(cycle.operation & Microcycle::Read) {
+										scc_.write(int(word_address), 0xff);
+									} else {
+										scc_.write(int(word_address), cycle.value->halves.low);
+									}
+								}
+							}
+						}
+					break;
+
+					default:
+						if(cycle.operation & Microcycle::Read) {
+							LOG("Unrecognised read " << PADHEX(6) << (*cycle.address & 0xffffff));
+							cycle.value->halves.low = 0x00;
+						} else {
+							LOG("Unrecognised write %06x" << PADHEX(6) << (*cycle.address & 0xffffff));
+						}
+					break;
+				}
+				if(cycle.operation & Microcycle::SelectWord) cycle.value->halves.high = 0xff;
+
+				return delay;
+			}
+
+			// Having reached here, this is a RAM or ROM access.
+
+			// When ROM overlay is enabled, the ROM begins at both $000000 and $400000,
+			// and RAM is available at $600000.
+			//
+			// Otherwise RAM is mapped at $000000 and ROM from $400000.
+			uint16_t *memory_base;
+			if(
+				(!ROM_is_overlay_ && word_address < 0x200000) ||
+				(ROM_is_overlay_ && word_address >= 0x300000)
+			) {
+				memory_base = ram_;
+				word_address &= ram_mask_;
+
+				// This is coupled with the Macintosh implementation of video; the magic
+				// constant should probably be factored into the Video class.
+				// It embodies knowledge of the fact that video (and audio) will always
+				// be fetched from the final $d900 bytes (i.e. $6c80 words) of memory.
+				// (And that ram_mask_ = ram size - 1).
+//				if(word_address > ram_mask_ - 0x6c80)
+					update_video();
+			} else {
+				memory_base = rom_;
+				word_address &= rom_mask_;
+
+				// Writes to ROM have no effect, and it doesn't mirror above 0x60000.
+				if(!(cycle.operation & Microcycle::Read)) return delay;
+				if(word_address >= 0x300000) {
+					if(cycle.operation & Microcycle::SelectWord) {
+						cycle.value->full = 0xffff;
+					} else {
+						cycle.value->halves.low = 0xff;
+					}
+					return delay;
+				}
+			}
+
+			switch(cycle.operation & (Microcycle::SelectWord | Microcycle::SelectByte | Microcycle::Read | Microcycle::InterruptAcknowledge)) {
+				default:
+				break;
+
+				// Catches the deliberation set of operation to 0 above.
+				case 0: break;
+
+				case Microcycle::InterruptAcknowledge | Microcycle::SelectByte:
+					// The Macintosh uses autovectored interrupts.
+					mc68000_.set_is_peripheral_address(true);
+				break;
+
+				case Microcycle::SelectWord | Microcycle::Read:
+					cycle.value->full = memory_base[word_address];
+				break;
+				case Microcycle::SelectByte | Microcycle::Read:
+					cycle.value->halves.low = uint8_t(memory_base[word_address] >> cycle.byte_shift());
+				break;
+				case Microcycle::SelectWord:
+					memory_base[word_address] = cycle.value->full;
+				break;
+				case Microcycle::SelectByte:
+					memory_base[word_address] = uint16_t(
+						(cycle.value->halves.low << cycle.byte_shift()) |
+						(memory_base[word_address] & cycle.untouched_byte_mask())
+					);
+				break;
+			}
+
+			/*
+				Normal memory map:
+
+				000000: 	RAM
+				400000: 	ROM
+				9FFFF8+:	SCC read operations
+				BFFFF8+:	SCC write operations
+				DFE1FF+:	IWM
+				EFE1FE+:	VIA
+			*/
+
+			return delay;
+		}
+
+		void flush() {
+			// Flush the video before the audio queue; in a Mac the
+			// video is responsible for providing part of the
+			// audio signal, so the two aren't as distinct as in
+			// most machines.
+			update_video();
+
+			// As above: flush audio after video.
+			via_.flush();
+			audio_.queue.perform();
+
+			// Experimental?
+			iwm_.flush();
+		}
+
+		void set_rom_is_overlay(bool rom_is_overlay) {
+			ROM_is_overlay_ = rom_is_overlay;
+		}
+
+		bool video_is_outputting() {
+			return video_.is_outputting(time_since_video_update_);
+		}
+
+		void set_use_alternate_buffers(bool use_alternate_screen_buffer, bool use_alternate_audio_buffer) {
+			update_video();
+			video_.set_use_alternate_buffers(use_alternate_screen_buffer, use_alternate_audio_buffer);
+		}
+
+		bool insert_media(const Analyser::Static::Media &media) override {
+			if(media.disks.empty())
+				return false;
+
+			// TODO: shouldn't allow disks to be replaced like this, as the Mac
+			// uses software eject. Will need to expand messaging ability of
+			// insert_media.
+			if(drives_[0].has_disk())
+				drives_[1].set_disk(media.disks[0]);
+			else
+				drives_[0].set_disk(media.disks[0]);
+
+			return true;
+		}
+
+		// MARK: Keyboard input.
+
+		KeyboardMapper *get_keyboard_mapper() override {
+			return &keyboard_mapper_;
+		}
+
+		void set_key_state(uint16_t key, bool is_pressed) override {
+			keyboard_.enqueue_key_state(key, is_pressed);
+		}
+
+		// TODO: clear all keys.
+
+		// MARK: Interrupt updates.
+
+		void did_change_interrupt_status(Zilog::SCC::z8530 *sender, bool new_status) override {
+			update_interrupt_input();
+		}
+
+		void update_interrupt_input() {
+			// Update interrupt input.
+			// TODO: does this really cascade like this?
+			if(scc_.get_interrupt_line()) {
+				mc68000_.set_interrupt_level(2);
+			} else if(via_.get_interrupt_line()) {
+				mc68000_.set_interrupt_level(1);
+			} else {
+				mc68000_.set_interrupt_level(0);
+			}
+		}
+
+	private:
+		void update_video() {
+			video_.run_for(time_since_video_update_.flush<HalfCycles>());
+			time_until_video_event_ = video_.get_next_sequence_point();
+		}
+
+		Inputs::Mouse &get_mouse() override {
+			return mouse_;
+		}
+
+		struct IWM {
+			IWM(int clock_rate) : iwm(clock_rate) {}
+
+			HalfCycles time_since_update;
+			Apple::IWM iwm;
+
+			void flush() {
+				iwm.run_for(time_since_update.flush<Cycles>());
+			}
+		};
+
+		class VIAPortHandler: public MOS::MOS6522::PortHandler {
+			public:
+				VIAPortHandler(ConcreteMachine &machine, RealTimeClock &clock, Keyboard &keyboard, Video &video, DeferredAudio &audio, IWM &iwm, Inputs::QuadratureMouse &mouse) :
+					machine_(machine), clock_(clock), keyboard_(keyboard), video_(video), audio_(audio), iwm_(iwm), mouse_(mouse) {}
+
+				using Port = MOS::MOS6522::Port;
+				using Line = MOS::MOS6522::Line;
+
+				void set_port_output(Port port, uint8_t value, uint8_t direction_mask) {
+					/*
+						Peripheral lines: keyboard data, interrupt configuration.
+						(See p176 [/215])
+					*/
+					switch(port) {
+						case Port::A:
+							/*
+								Port A:
+									b7:	[input] SCC wait/request (/W/REQA and /W/REQB wired together for a logical OR)
+									b6:	0 = alternate screen buffer, 1 = main screen buffer
+									b5:	floppy disk SEL state control (upper/lower head "among other things")
+									b4:	1 = use ROM overlay memory map, 0 = use ordinary memory map
+									b3:	0 = use alternate sound buffer, 1 = use ordinary sound buffer
+									b2–b0:	audio output volume
+							*/
+							iwm_.flush();
+							iwm_.iwm.set_select(!!(value & 0x20));
+
+							machine_.set_use_alternate_buffers(!(value & 0x40), !(value&0x08));
+							machine_.set_rom_is_overlay(!!(value & 0x10));
+
+							audio_.flush();
+							audio_.audio.set_volume(value & 7);
+						break;
+
+						case Port::B:
+							/*
+								Port B:
+									b7:	0 = sound enabled, 1 = sound disabled
+									b6:	[input] 0 = video beam in visible portion of line, 1 = outside
+									b5:	[input] mouse y2
+									b4:	[input] mouse x2
+									b3:	[input] 0 = mouse button down, 1 = up
+									b2:	0 = real-time clock enabled, 1 = disabled
+									b1:	clock's data-clock line
+									b0:	clock's serial data line
+							*/
+							if(value & 0x4) clock_.abort();
+							else clock_.set_input(!!(value & 0x2), !!(value & 0x1));
+
+							audio_.flush();
+							audio_.audio.set_enabled(!(value & 0x80));
+						break;
+					}
+				}
+
+				uint8_t get_port_input(Port port) {
+					switch(port) {
+						case Port::A:
+//							printf("6522 r A\n");
+						return 0x00;	// TODO: b7 = SCC wait/request
+
+						case Port::B:
+						return uint8_t(
+							((mouse_.get_button_mask() & 1) ? 0x00 : 0x08) |
+							((mouse_.get_channel(0) & 2) << 3) |
+							((mouse_.get_channel(1) & 2) << 4) |
+							(clock_.get_data() ? 0x02 : 0x00) |
+							(machine_.video_is_outputting() ? 0x00 : 0x40)
+						);
+					}
+
+					// Should be unreachable.
+					return 0xff;
+				}
+
+				void set_control_line_output(Port port, Line line, bool value) {
+					/*
+						Keyboard wiring (I believe):
+						CB2 = data		(input/output)
+						CB1 = clock		(input)
+
+						CA2 is used for receiving RTC interrupts.
+						CA1 is used for receiving vsync.
+					*/
+					if(port == Port::B && line == Line::Two) {
+						keyboard_.set_input(value);
+					}
+					else LOG("Unhandled control line output: " << (port ? 'B' : 'A') << int(line));
+				}
+
+				void run_for(HalfCycles duration) {
+					// The 6522 enjoys a divide-by-ten, so multiply back up here to make the
+					// divided-by-two clock the audio works on.
+					audio_.time_since_update += HalfCycles(duration.as_int() * 5);
+				}
+
+				void flush() {
+					audio_.flush();
+				}
+
+				void set_interrupt_status(bool status) {
+					machine_.update_interrupt_input();
+				}
+
+			private:
+				ConcreteMachine &machine_;
+				RealTimeClock &clock_;
+				Keyboard &keyboard_;
+				Video &video_;
+				DeferredAudio &audio_;
+				IWM &iwm_;
+				Inputs::QuadratureMouse &mouse_;
+		};
+
+		CPU::MC68000::Processor<ConcreteMachine, true> mc68000_;
+
+		DriveSpeedAccumulator drive_speed_accumulator_;
+		IWM iwm_;
+
+		DeferredAudio audio_;
+		Video video_;
+
+		RealTimeClock clock_;
+		Keyboard keyboard_;
+
+		MOS::MOS6522::MOS6522<VIAPortHandler> via_;
+ 		VIAPortHandler via_port_handler_;
+
+ 		Zilog::SCC::z8530 scc_;
+
+ 		HalfCycles via_clock_;
+ 		HalfCycles real_time_clock_;
+ 		HalfCycles keyboard_clock_;
+ 		HalfCycles time_since_video_update_;
+ 		HalfCycles time_until_video_event_;
+ 		HalfCycles time_since_mouse_update_;
+
+		bool ROM_is_overlay_ = true;
+		int phase_ = 1;
+
+		DoubleDensityDrive drives_[2];
+		Inputs::QuadratureMouse mouse_;
+
+		Apple::Macintosh::KeyboardMapper keyboard_mapper_;
+
+		uint32_t ram_mask_ = 0;
+		uint32_t rom_mask_ = 0;
+		uint16_t rom_[64*1024];
+		uint16_t ram_[256*1024];
+};
+
+}
+}
+
+using namespace Apple::Macintosh;
+
+Machine *Machine::Macintosh(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher) {
+	auto *const mac_target = dynamic_cast<const Analyser::Static::Macintosh::Target *>(target);
+
+	using Model = Analyser::Static::Macintosh::Target::Model;
+	switch(mac_target->model) {
+		default:
+		case Model::Mac128k:	return new ConcreteMachine<Model::Mac128k>(*mac_target, rom_fetcher);
+		case Model::Mac512k:	return new ConcreteMachine<Model::Mac512k>(*mac_target, rom_fetcher);
+		case Model::Mac512ke:	return new ConcreteMachine<Model::Mac512ke>(*mac_target, rom_fetcher);
+		case Model::MacPlus:	return new ConcreteMachine<Model::MacPlus>(*mac_target, rom_fetcher);
+	}
+}
+
+Machine::~Machine() {}

Machines/Apple/Macintosh/Macintosh.hpp

@@ -0,0 +1,30 @@
+//
+//  Macintosh.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 03/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef Macintosh_hpp
+#define Macintosh_hpp
+
+#include "../../../Analyser/Static/StaticAnalyser.hpp"
+#include "../../ROMMachine.hpp"
+
+namespace Apple {
+namespace Macintosh {
+
+class Machine {
+	public:
+		virtual ~Machine();
+
+		/// Creates and returns a Macintosh.
+		static Machine *Macintosh(const Analyser::Static::Target *target, const ROMMachine::ROMFetcher &rom_fetcher);
+};
+
+
+}
+}
+
+#endif /* Macintosh_hpp */

Machines/Apple/Macintosh/RealTimeClock.hpp

@@ -0,0 +1,166 @@
+//
+//  RealTimeClock.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef RealTimeClock_hpp
+#define RealTimeClock_hpp
+
+#include "../../Utility/MemoryFuzzer.hpp"
+
+namespace Apple {
+namespace Macintosh {
+
+/*!
+	Models the storage component of Apple's real-time clock.
+
+	Since tracking of time is pushed to this class, it is assumed
+	that whomever is translating real time into emulated time
+	will notify the VIA of a potential interrupt.
+*/
+class RealTimeClock {
+	public:
+		RealTimeClock() {
+			// TODO: this should persist, if possible, rather than
+			// being randomly initialised.
+			Memory::Fuzz(data_, sizeof(data_));
+		}
+
+		/*!
+			Advances the clock by 1 second.
+
+			The caller should also notify the VIA.
+		*/
+		void update() {
+			for(int c = 0; c < 4; ++c) {
+				++seconds_[c];
+				if(seconds_[c]) break;
+			}
+		}
+
+		/*!
+			Sets the current clock and data inputs to the clock.
+		*/
+		void set_input(bool clock, bool data) {
+			/*
+				Documented commands:
+
+					z0000001		Seconds register 0 (lowest order byte)
+					z0000101		Seconds register 1
+					z0001001		Seconds register 2
+					z0001101		Seconds register 3
+					00110001		Test register (write only)
+					00110101		Write-protect register (write only)
+					z010aa01		RAM addresses 0x10 - 0x13
+					z1aaaa01		RAM addresses 0x00 – 0x0f
+
+					z = 1 => a read; z = 0 => a write.
+
+				The top bit of the write-protect register enables (0) or disables (1)
+				writes to other locations.
+
+				All the documentation says about the test register is to set the top
+				two bits to 0 for normal operation. Abnormal operation is undefined.
+
+				The data line is valid when the clock transitions to level 0.
+			*/
+
+			if(clock && !previous_clock_) {
+				// Shift into the command_ register, no matter what.
+				command_ = uint16_t((command_ << 1) | (data ? 1 : 0));
+				result_ <<= 1;
+
+				// Increment phase.
+				++phase_;
+
+				// When phase hits 8, inspect the command.
+				// If it's a read, prepare a result.
+				if(phase_ == 8) {
+					if(command_ & 0x80) {
+						// A read.
+						const auto address = (command_ >> 2) & 0x1f;
+
+						// Begin pessimistically.
+						result_ = 0xff;
+
+						if(address < 4) {
+							result_ = seconds_[address];
+						} else if(address >= 0x10) {
+							result_ = data_[address & 0xf];
+						} else if(address >= 0x8 && address <= 0xb) {
+							result_ = data_[0x10 + (address & 0x3)];
+						}
+					}
+				}
+
+				// If phase hits 16 and this was a read command,
+				// just stop. If it was a write command, do the
+				// actual write.
+				if(phase_ == 16) {
+					if(!(command_ & 0x8000)) {
+						// A write.
+
+						const auto address = (command_ >> 10) & 0x1f;
+						const uint8_t value = uint8_t(command_ & 0xff);
+
+						// First test: is this to the write-protect register?
+						if(address == 0xd) {
+							write_protect_ = value;
+						}
+
+						// No other writing is permitted if the write protect
+						// register won't allow it.
+						if(!(write_protect_ & 0x80)) {
+							if(address < 4) {
+								seconds_[address] = value;
+							} else if(address >= 0x10) {
+								data_[address & 0xf] = value;
+							} else if(address >= 0x8 && address <= 0xb) {
+								data_[0x10 + (address & 0x3)] = value;
+							}
+						}
+					}
+
+					// A phase of 16 always ends the command, so reset here.
+					abort();
+				}
+			}
+
+			previous_clock_ = clock;
+		}
+
+		/*!
+			Reads the current data output level from the clock.
+		*/
+		bool get_data() {
+			return !!(result_ & 0x80);
+		}
+
+		/*!
+			Announces that a serial command has been aborted.
+		*/
+		void abort() {
+			result_ = 0;
+			phase_ = 0;
+			command_ = 0;
+		}
+
+	private:
+		uint8_t data_[0x14];
+		uint8_t seconds_[4];
+		uint8_t write_protect_;
+
+		int phase_ = 0;
+		uint16_t command_;
+		uint8_t result_ = 0;
+
+		bool previous_clock_ = false;
+};
+
+}
+}
+
+#endif /* RealTimeClock_hpp */

Machines/Apple/Macintosh/Video.cpp

@@ -0,0 +1,201 @@
+//
+//  Video.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 03/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "Video.hpp"
+
+#include <algorithm>
+
+using namespace Apple::Macintosh;
+
+namespace {
+
+const HalfCycles line_length(704);
+const int number_of_lines = 370;
+const HalfCycles frame_length(line_length * HalfCycles(number_of_lines));
+const int sync_start = 36;
+const int sync_end = 38;
+
+}
+
+// Re: CRT timings, see the Apple Guide to the Macintosh Hardware Family,
+// bottom of page 400:
+//
+//	"For each scan line, 512 pixels are drawn on the screen ...
+//	The horizontal blanking interval takes the time of an additional 192 pixels"
+//
+// And, at the top of 401:
+//
+//	"The visible portion of a full-screen display consists of 342 horizontal scan lines...
+//	During the vertical blanking interval, the turned-off beam ... traces out an additional 28 scan lines,"
+//
+Video::Video(uint16_t *ram, DeferredAudio &audio, DriveSpeedAccumulator &drive_speed_accumulator) :
+	audio_(audio),
+	drive_speed_accumulator_(drive_speed_accumulator),
+ 	crt_(704, 1, 370, Outputs::Display::ColourSpace::YIQ, 1, 1, 6, false, Outputs::Display::InputDataType::Luminance1),
+ 	ram_(ram) {
+
+ 	crt_.set_display_type(Outputs::Display::DisplayType::RGB);
+	crt_.set_visible_area(Outputs::Display::Rect(0.08f, -0.025f, 0.82f, 0.82f));
+	crt_.set_aspect_ratio(1.73f);	// The Mac uses a non-standard scanning area.
+}
+
+void Video::set_scan_target(Outputs::Display::ScanTarget *scan_target) {
+	crt_.set_scan_target(scan_target);
+}
+
+void Video::run_for(HalfCycles duration) {
+	// Determine the current video and audio bases. These values don't appear to be latched, they apply immediately.
+	const size_t video_base = (use_alternate_screen_buffer_ ? (0xffff2700 >> 1) : (0xffffa700 >> 1)) & ram_mask_;
+	const size_t audio_base = (use_alternate_audio_buffer_ ? (0xffffa100 >> 1) : (0xfffffd00 >> 1)) & ram_mask_;
+
+	// The number of HalfCycles is literally the number of pixel clocks to move through,
+	// since pixel output occurs at twice the processor clock. So divide by 16 to get
+	// the number of fetches.
+	while(duration > HalfCycles(0)) {
+		const auto pixel_start = frame_position_ % line_length;
+		const int line = (frame_position_ / line_length).as_int();
+
+		const auto cycles_left_in_line = std::min(line_length - pixel_start, duration);
+
+		// Line timing, entirely invented as I can find exactly zero words of documentation:
+		//
+		//	First 342 lines:
+		//
+		//	First 32 words = pixels;
+		//	next 5 words = right border;
+		//	next 2 words = sync level;
+		//	final 5 words = left border.
+		//
+		//	Then 12 lines of border, 3 of sync, 11 more of border.
+
+		const int first_word = pixel_start.as_int() >> 4;
+		const int final_word = (pixel_start + cycles_left_in_line).as_int() >> 4;
+
+		if(first_word != final_word) {
+			if(line < 342) {
+				// If there are any pixels left to output, do so.
+				if(first_word < 32) {
+					const int final_pixel_word = std::min(final_word, 32);
+
+					if(!first_word) {
+						pixel_buffer_ = crt_.begin_data(512);
+					}
+
+					if(pixel_buffer_) {
+						for(int c = first_word; c < final_pixel_word; ++c) {
+							uint16_t pixels = ram_[video_base + video_address_] ^ 0xffff;
+							++video_address_;
+
+							pixel_buffer_[15] = pixels & 0x01;
+							pixel_buffer_[14] = pixels & 0x02;
+							pixel_buffer_[13] = pixels & 0x04;
+							pixel_buffer_[12] = pixels & 0x08;
+							pixel_buffer_[11] = pixels & 0x10;
+							pixel_buffer_[10] = pixels & 0x20;
+							pixel_buffer_[9] = pixels & 0x40;
+							pixel_buffer_[8] = pixels & 0x80;
+
+							pixels >>= 8;
+							pixel_buffer_[7] = pixels & 0x01;
+							pixel_buffer_[6] = pixels & 0x02;
+							pixel_buffer_[5] = pixels & 0x04;
+							pixel_buffer_[4] = pixels & 0x08;
+							pixel_buffer_[3] = pixels & 0x10;
+							pixel_buffer_[2] = pixels & 0x20;
+							pixel_buffer_[1] = pixels & 0x40;
+							pixel_buffer_[0] = pixels & 0x80;
+
+							pixel_buffer_ += 16;
+						}
+					}
+
+					if(final_pixel_word == 32) {
+						crt_.output_data(512);
+					}
+				}
+
+				if(first_word < sync_start && final_word >= sync_start)	crt_.output_blank((sync_start - 32) * 16);
+				if(first_word < sync_end && final_word >= sync_end)		crt_.output_sync((sync_end - sync_start) * 16);
+				if(final_word == 44)									crt_.output_blank((44 - sync_end) * 16);
+			} else if(final_word == 44) {
+				if(line >= 353 && line < 356) {
+					/* Output a sync line. */
+					crt_.output_sync(sync_start * 16);
+					crt_.output_blank((sync_end - sync_start) * 16);
+					crt_.output_sync((44 - sync_end) * 16);
+				} else {
+					/* Output a blank line. */
+					crt_.output_blank(sync_start * 16);
+					crt_.output_sync((sync_end - sync_start) * 16);
+					crt_.output_blank((44 - sync_end) * 16);
+				}
+			}
+
+			// Audio and disk fetches occur "just before video data".
+			if(final_word == 44) {
+				const uint16_t audio_word = ram_[audio_address_ + audio_base];
+				++audio_address_;
+				audio_.audio.post_sample(audio_word >> 8);
+				drive_speed_accumulator_.post_sample(audio_word & 0xff);
+			}
+		}
+
+		duration -= cycles_left_in_line;
+		frame_position_ = frame_position_ + cycles_left_in_line;
+		if(frame_position_ == frame_length) {
+			frame_position_ = HalfCycles(0);
+			/*
+				Video: $1A700 and the alternate buffer starts at $12700; for a 512K Macintosh, add $60000 to these numbers.
+			*/
+			video_address_ = 0;
+
+			/*
+				"The main sound buffer is at $1FD00 in a 128K Macintosh, and the alternate buffer is at $1A100;
+				for a 512K Macintosh, add $60000 to these values."
+			*/
+			audio_address_ = 0;
+		}
+	}
+}
+
+bool Video::vsync() {
+	const int line = (frame_position_ / line_length).as_int();
+	return line >= 353 && line < 356;
+}
+
+HalfCycles Video::get_next_sequence_point() {
+	const int line = (frame_position_ / line_length).as_int();
+	if(line >= 353 && line < 356) {
+		// Currently in vsync, so get time until start of line 357,
+		// when vsync will end.
+		return HalfCycles(356) * line_length - frame_position_;
+	} else {
+		// Not currently in vsync, so get time until start of line 353.
+		const auto start_of_vsync = HalfCycles(353) * line_length;
+		if(frame_position_ < start_of_vsync)
+			return start_of_vsync - frame_position_;
+		else
+			return start_of_vsync + HalfCycles(number_of_lines) * line_length - frame_position_;
+	}
+}
+
+bool Video::is_outputting(HalfCycles offset) {
+	const auto offset_position = frame_position_ + offset % frame_length;
+	const int column = (offset_position % line_length).as_int() >> 4;
+	const int line = (offset_position / line_length).as_int();
+	return line < 342 && column < 32;
+}
+
+void Video::set_use_alternate_buffers(bool use_alternate_screen_buffer, bool use_alternate_audio_buffer) {
+	use_alternate_screen_buffer_ = use_alternate_screen_buffer;
+	use_alternate_audio_buffer_ = use_alternate_audio_buffer;
+}
+
+void Video::set_ram_mask(uint32_t mask) {
+	ram_mask_ = mask;
+}

Machines/Apple/Macintosh/Video.hpp

@@ -0,0 +1,94 @@
+//
+//  Video.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 03/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef Video_hpp
+#define Video_hpp
+
+#include "../../../Outputs/CRT/CRT.hpp"
+#include "../../../ClockReceiver/ClockReceiver.hpp"
+#include "DeferredAudio.hpp"
+#include "DriveSpeedAccumulator.hpp"
+
+namespace Apple {
+namespace Macintosh {
+
+/*!
+	Models the 68000-era Macintosh video hardware, producing a 512x348 pixel image,
+	within a total scanning area of 370 lines, at 352 cycles per line.
+
+	This class also collects audio and 400kb drive-speed data, forwarding those values.
+*/
+class Video {
+	public:
+		/*!
+			Constructs an instance of @c Video sourcing its pixel data from @c ram and
+			providing audio and drive-speed bytes to @c audio and @c drive_speed_accumulator.
+		*/
+		Video(uint16_t *ram, DeferredAudio &audio, DriveSpeedAccumulator &drive_speed_accumulator);
+
+		/*!
+			Sets the target device for video data.
+		*/
+		void set_scan_target(Outputs::Display::ScanTarget *scan_target);
+
+		/*!
+			Produces the next @c duration period of pixels.
+		*/
+		void run_for(HalfCycles duration);
+
+		/*!
+			Sets whether the alternate screen and/or audio buffers should be used to source data.
+		*/
+		void set_use_alternate_buffers(bool use_alternate_screen_buffer, bool use_alternate_audio_buffer);
+
+		/*!
+			Provides a mask indicating which parts of the generated video and audio/drive addresses are
+			actually decoded, accessing *word-sized memory*; e.g. for a 128kb Macintosh this should be (1 << 16) - 1 = 0xffff.
+		*/
+		void set_ram_mask(uint32_t);
+
+		/*!
+			@returns @c true if the video is currently outputting a vertical sync, @c false otherwise.
+		*/
+		bool vsync();
+
+		/*
+			@returns @c true if in @c offset half cycles from now, the video will be outputting pixels;
+				@c false otherwise.
+		*/
+		bool is_outputting(HalfCycles offset = HalfCycles(0));
+
+		/*!
+			@returns the amount of time until there is next a transition on the
+				vsync signal.
+		*/
+		HalfCycles get_next_sequence_point();
+
+	private:
+		DeferredAudio &audio_;
+		DriveSpeedAccumulator &drive_speed_accumulator_;
+
+		Outputs::CRT::CRT crt_;
+		uint16_t *ram_ = nullptr;
+		uint32_t ram_mask_ = 0;
+
+		HalfCycles frame_position_;
+
+		size_t video_address_ = 0;
+		size_t audio_address_ = 0;
+
+		uint8_t *pixel_buffer_ = nullptr;
+
+		bool use_alternate_screen_buffer_ = false;
+		bool use_alternate_audio_buffer_ = false;
+};
+
+}
+}
+
+#endif /* Video_hpp */

Machines/Atari2600/Bus.hpp

@@ -55,13 +55,13 @@ class Bus {
 		// video backlog accumulation counter
 		Cycles cycles_since_video_update_;
 		inline void update_video() {
-			tia_.run_for(cycles_since_video_update_.flush());
+			tia_.run_for(cycles_since_video_update_.flush<Cycles>());
 		}
 
 		// RIOT backlog accumulation counter
 		Cycles cycles_since_6532_update_;
 		inline void update_6532() {
-			mos6532_.run_for(cycles_since_6532_update_.flush());
+			mos6532_.run_for(cycles_since_6532_update_.flush<Cycles>());
 		}
 };
 

Machines/ColecoVision/ColecoVision.cpp

@@ -17,7 +17,9 @@
 #include "../CRTMachine.hpp"
 #include "../JoystickMachine.hpp"
 
+#include "../../Configurable/StandardOptions.hpp"
 #include "../../ClockReceiver/ForceInline.hpp"
+#include "../../ClockReceiver/JustInTime.hpp"
 
 #include "../../Outputs/Speaker/Implementation/CompoundSource.hpp"
 #include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
@@ -31,6 +33,12 @@ const int sn76489_divider = 2;
 namespace Coleco {
 namespace Vision {
 
+std::vector<std::unique_ptr<Configurable::Option>> get_options() {
+	return Configurable::standard_options(
+		static_cast<Configurable::StandardOptions>(Configurable::DisplaySVideo | Configurable::DisplayCompositeColour)
+	);
+}
+
 class Joystick: public Inputs::ConcreteJoystick {
 	public:
 		Joystick() :
@@ -107,6 +115,7 @@ class ConcreteMachine:
 	public Machine,
 	public CPU::Z80::BusHandler,
 	public CRTMachine::Machine,
+	public Configurable::Device,
 	public JoystickMachine::Machine {
 
 	public:
@@ -123,8 +132,7 @@ class ConcreteMachine:
 			joysticks_.emplace_back(new Joystick);
 
 			const auto roms = rom_fetcher(
-				"ColecoVision",
-				{ "coleco.rom" });
+				{ {"ColecoVision", "the ColecoVision BIOS", "coleco.rom", 8*1024, 0x3aa93ef3} });
 
 			if(!roms[0]) {
 				throw ROMMachine::Error::MissingROMs;
@@ -162,7 +170,7 @@ class ConcreteMachine:
 			}
 
 			// ColecoVisions have composite output only.
-			vdp_.set_display_type(Outputs::Display::DisplayType::CompositeColour);
+			vdp_->set_display_type(Outputs::Display::DisplayType::CompositeColour);
 		}
 
 		~ConcreteMachine() {
@@ -174,11 +182,11 @@ class ConcreteMachine:
 		}
 
 		void set_scan_target(Outputs::Display::ScanTarget *scan_target) override {
-			vdp_.set_scan_target(scan_target);
+			vdp_->set_scan_target(scan_target);
 		}
 
 		void set_display_type(Outputs::Display::DisplayType display_type) override {
-			vdp_.set_display_type(display_type);
+			vdp_->set_display_type(display_type);
 		}
 
 		Outputs::Speaker::Speaker *get_speaker() override {
@@ -203,7 +211,7 @@ class ConcreteMachine:
 			}
 			const HalfCycles length = cycle.length + penalty;
 
-			time_since_vdp_update_ += length;
+			vdp_ += length;
 			time_since_sn76489_update_ += length;
 
 			// Act only if necessary.
@@ -248,10 +256,9 @@ class ConcreteMachine:
 					case CPU::Z80::PartialMachineCycle::Input:
 						switch((address >> 5) & 7) {
 							case 5:
-								update_video();
-								*cycle.value = vdp_.get_register(address);
-								z80_.set_non_maskable_interrupt_line(vdp_.get_interrupt_line());
-								time_until_interrupt_ = vdp_.get_time_until_interrupt();
+								*cycle.value = vdp_->get_register(address);
+								z80_.set_non_maskable_interrupt_line(vdp_->get_interrupt_line());
+								time_until_interrupt_ = vdp_->get_time_until_interrupt();
 							break;
 
 							case 7: {
@@ -292,10 +299,9 @@ class ConcreteMachine:
 							break;
 
 							case 5:
-								update_video();
-								vdp_.set_register(address, *cycle.value);
-								z80_.set_non_maskable_interrupt_line(vdp_.get_interrupt_line());
-								time_until_interrupt_ = vdp_.get_time_until_interrupt();
+								vdp_->set_register(address, *cycle.value);
+								z80_.set_non_maskable_interrupt_line(vdp_->get_interrupt_line());
+								time_until_interrupt_ = vdp_->get_time_until_interrupt();
 							break;
 
 							case 7:
@@ -347,7 +353,7 @@ class ConcreteMachine:
 		}
 
 		void flush() {
-			update_video();
+			vdp_.flush();
 			update_audio();
 			audio_queue_.perform();
 		}
@@ -357,6 +363,30 @@ class ConcreteMachine:
 			return confidence_counter_.get_confidence();
 		}
 
+		// MARK: - Configuration options.
+		std::vector<std::unique_ptr<Configurable::Option>> get_options() override {
+			return Coleco::Vision::get_options();
+		}
+
+		void set_selections(const Configurable::SelectionSet &selections_by_option) override {
+			Configurable::Display display;
+			if(Configurable::get_display(selections_by_option, display)) {
+				set_video_signal_configurable(display);
+			}
+		}
+
+		Configurable::SelectionSet get_accurate_selections() override {
+			Configurable::SelectionSet selection_set;
+			Configurable::append_display_selection(selection_set, Configurable::Display::CompositeColour);
+			return selection_set;
+		}
+
+		Configurable::SelectionSet get_user_friendly_selections() override {
+			Configurable::SelectionSet selection_set;
+			Configurable::append_display_selection(selection_set, Configurable::Display::SVideo);
+			return selection_set;
+		}
+
 	private:
 		inline void page_megacart(uint16_t address) {
 			const std::size_t selected_start = (static_cast<std::size_t>(address&63) << 14) % cartridge_.size();
@@ -365,12 +395,9 @@ class ConcreteMachine:
 		inline void update_audio() {
 			speaker_.run_for(audio_queue_, time_since_sn76489_update_.divide_cycles(Cycles(sn76489_divider)));
 		}
-		inline void update_video() {
-			vdp_.run_for(time_since_vdp_update_.flush());
-		}
 
 		CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
-		TI::TMS::TMS9918 vdp_;
+		JustInTimeActor<TI::TMS::TMS9918, HalfCycles> vdp_;
 
 		Concurrency::DeferringAsyncTaskQueue audio_queue_;
 		TI::SN76489 sn76489_;
@@ -393,7 +420,6 @@ class ConcreteMachine:
 		std::vector<std::unique_ptr<Inputs::Joystick>> joysticks_;
 		bool joysticks_in_keypad_mode_ = false;
 
-		HalfCycles time_since_vdp_update_;
 		HalfCycles time_since_sn76489_update_;
 		HalfCycles time_until_interrupt_;
 

Machines/ColecoVision/ColecoVision.hpp

@@ -9,12 +9,15 @@
 #ifndef ColecoVision_hpp
 #define ColecoVision_hpp
 
+#include "../../Configurable/Configurable.hpp"
 #include "../../Analyser/Static/StaticAnalyser.hpp"
 #include "../ROMMachine.hpp"
 
 namespace Coleco {
 namespace Vision {
 
+std::vector<std::unique_ptr<Configurable::Option>> get_options();
+
 class Machine {
 	public:
 		virtual ~Machine();

Machines/Commodore/1540/Implementation/C1540.cpp

@@ -39,13 +39,20 @@ MachineBase::MachineBase(Personality personality, const ROMMachine::ROMFetcher &
 	// attach the only drive there is
 	set_drive(drive_);
 
-	std::string rom_name;
+	std::string device_name;
+	uint32_t crc = 0;
 	switch(personality) {
-		case Personality::C1540:	rom_name = "1540.bin";	break;
-		case Personality::C1541:	rom_name = "1541.bin";	break;
+		case Personality::C1540:
+			device_name = "1540";
+			crc = 0x718d42b1;
+		break;
+		case Personality::C1541:
+			device_name = "1541";
+			crc = 0xfb760019;
+		break;
 	}
 
-	auto roms = rom_fetcher("Commodore1540", {rom_name});
+	auto roms = rom_fetcher({ {"Commodore1540", "the " + device_name + " ROM", device_name + ".bin", 16*1024, crc} });
 	if(!roms[0]) {
 		throw ROMMachine::Error::MissingROMs;
 	}

Machines/Commodore/Vic-20/Vic20.cpp

@@ -323,31 +323,34 @@ class ConcreteMachine:
 			// install a joystick
 			joysticks_.emplace_back(new Joystick(*user_port_via_port_handler_, *keyboard_via_port_handler_));
 
-			std::vector<std::string> rom_names = { "basic.bin" };
+			const std::string machine_name = "Vic20";
+			std::vector<ROMMachine::ROM> rom_names = {
+				{machine_name, "the VIC-20 BASIC ROM", "basic.bin", 8*1024, 0xdb4c43c1}
+			};
 			switch(target.region) {
 				default:
-					rom_names.push_back("characters-english.bin");
-					rom_names.push_back("kernel-pal.bin");
+					rom_names.emplace_back(machine_name, "the English-language VIC-20 character ROM", "characters-english.bin", 4*1024, 0x83e032a6);
+					rom_names.emplace_back(machine_name, "the English-language PAL VIC-20 kernel ROM", "kernel-pal.bin", 8*1024, 0x4be07cb4);
 				break;
 				case Analyser::Static::Commodore::Target::Region::American:
-					rom_names.push_back("characters-english.bin");
-					rom_names.push_back("kernel-ntsc.bin");
+					rom_names.emplace_back(machine_name, "the English-language VIC-20 character ROM", "characters-english.bin", 4*1024, 0x83e032a6);
+					rom_names.emplace_back(machine_name, "the English-language NTSC VIC-20 kernel ROM", "kernel-ntsc.bin", 8*1024, 0xe5e7c174);
 				break;
 				case Analyser::Static::Commodore::Target::Region::Danish:
-					rom_names.push_back("characters-danish.bin");
-					rom_names.push_back("kernel-danish.bin");
+					rom_names.emplace_back(machine_name, "the Danish VIC-20 character ROM", "characters-danish.bin", 4*1024, 0x7fc11454);
+					rom_names.emplace_back(machine_name, "the Danish VIC-20 kernel ROM", "kernel-danish.bin", 8*1024, 0x02adaf16);
 				break;
 				case Analyser::Static::Commodore::Target::Region::Japanese:
-					rom_names.push_back("characters-japanese.bin");
-					rom_names.push_back("kernel-japanese.bin");
+					rom_names.emplace_back(machine_name, "the Japanese VIC-20 character ROM", "characters-japanese.bin", 4*1024, 0xfcfd8a4b);
+					rom_names.emplace_back(machine_name, "the Japanese VIC-20 kernel ROM", "kernel-japanese.bin", 8*1024, 0x336900d7);
 				break;
 				case Analyser::Static::Commodore::Target::Region::Swedish:
-					rom_names.push_back("characters-swedish.bin");
-					rom_names.push_back("kernel-japanese.bin");
+					rom_names.emplace_back(machine_name, "the Swedish VIC-20 character ROM", "characters-swedish.bin", 4*1024, 0xd808551d);
+					rom_names.emplace_back(machine_name, "the Swedish VIC-20 kernel ROM", "kernel-swedish.bin", 8*1024, 0xb2a60662);
 				break;
 			}
 
-			const auto roms = rom_fetcher("Vic20", rom_names);
+			const auto roms = rom_fetcher(rom_names);
 
 			for(const auto &rom: roms) {
 				if(!rom) {
@@ -699,7 +702,7 @@ class ConcreteMachine:
 
 	private:
 		void update_video() {
-			mos6560_.run_for(cycles_since_mos6560_update_.flush());
+			mos6560_.run_for(cycles_since_mos6560_update_.flush<Cycles>());
 		}
 		CPU::MOS6502::Processor<CPU::MOS6502::Personality::P6502, ConcreteMachine, false> m6502_;
 

Machines/DynamicMachine.hpp

@@ -11,10 +11,13 @@
 
 #include "../Configurable/Configurable.hpp"
 #include "../Activity/Source.hpp"
-#include "MediaTarget.hpp"
+
 #include "CRTMachine.hpp"
 #include "JoystickMachine.hpp"
 #include "KeyboardMachine.hpp"
+#include "MediaTarget.hpp"
+#include "MouseMachine.hpp"
+
 #include "Utility/Typer.hpp"
 
 namespace Machine {
@@ -31,6 +34,7 @@ struct DynamicMachine {
 	virtual CRTMachine::Machine *crt_machine() = 0;
 	virtual JoystickMachine::Machine *joystick_machine() = 0;
 	virtual KeyboardMachine::Machine *keyboard_machine() = 0;
+	virtual MouseMachine::Machine *mouse_machine() = 0;
 	virtual MediaTarget::Machine *media_target() = 0;
 
 	/*!

Machines/Electron/Electron.cpp

@@ -62,17 +62,22 @@ class ConcreteMachine:
 			set_clock_rate(2000000);
 
 			speaker_.set_input_rate(2000000 / SoundGenerator::clock_rate_divider);
+			speaker_.set_high_frequency_cutoff(7000);
 
-			std::vector<std::string> rom_names = {"basic.rom", "os.rom"};
+			const std::string machine_name = "Electron";
+			std::vector<ROMMachine::ROM> required_roms = {
+				{machine_name, "the Acorn BASIC II ROM", "basic.rom", 16*1024, 0x79434781},
+				{machine_name, "the Electron MOS ROM", "os.rom", 16*1024, 0xbf63fb1f}
+			};
 			if(target.has_adfs) {
-				rom_names.push_back("ADFS-E00_1.rom");
-				rom_names.push_back("ADFS-E00_2.rom");
+				required_roms.emplace_back(machine_name, "the E00 ADFS ROM, first slot", "ADFS-E00_1.rom", 16*1024, 0x51523993);
+				required_roms.emplace_back(machine_name, "the E00 ADFS ROM, second slot", "ADFS-E00_2.rom", 16*1024, 0x8d17de0e);
 			}
-			const size_t dfs_rom_position = rom_names.size();
+			const size_t dfs_rom_position = required_roms.size();
 			if(target.has_dfs) {
-				rom_names.push_back("DFS-1770-2.20.rom");
+				required_roms.emplace_back(machine_name, "the 1770 DFS ROM", "DFS-1770-2.20.rom", 16*1024, 0xf3dc9bc5);
 			}
-			const auto roms = rom_fetcher("Electron", rom_names);
+			const auto roms = rom_fetcher(required_roms);
 
 			for(const auto &rom: roms) {
 				if(!rom) {
@@ -505,7 +510,7 @@ class ConcreteMachine:
 		// MARK: - Work deferral updates.
 		inline void update_display() {
 			if(cycles_since_display_update_ > 0) {
-				video_output_.run_for(cycles_since_display_update_.flush());
+				video_output_.run_for(cycles_since_display_update_.flush<Cycles>());
 			}
 		}
 

Machines/Electron/Keyboard.hpp

@@ -34,7 +34,7 @@ enum Key: uint16_t {
 };
 
 struct KeyboardMapper: public KeyboardMachine::MappedMachine::KeyboardMapper {
-	uint16_t mapped_key_for_key(Inputs::Keyboard::Key key);
+	uint16_t mapped_key_for_key(Inputs::Keyboard::Key key) override;
 };
 
 struct CharacterMapper: public ::Utility::CharacterMapper {

Machines/MSX/MSX.cpp

@@ -45,6 +45,7 @@
 
 #include "../../Configurable/StandardOptions.hpp"
 #include "../../ClockReceiver/ForceInline.hpp"
+#include "../../ClockReceiver/JustInTime.hpp"
 
 #include "../../Analyser/Static/MSX/Target.hpp"
 
@@ -173,33 +174,37 @@ class ConcreteMachine:
 			mixer_.set_relative_volumes({0.5f, 0.1f, 0.4f});
 
 			// Install the proper TV standard and select an ideal BIOS name.
-			std::vector<std::string> rom_names = {"msx.rom"};
+			const std::string machine_name = "MSX";
+			std::vector<ROMMachine::ROM> required_roms = {
+				{machine_name, "any MSX BIOS", "msx.rom", 32*1024, 0x94ee12f3}
+			};
 
 			bool is_ntsc = true;
 			uint8_t character_generator = 1;	/* 0 = Japan, 1 = USA, etc, 2 = USSR */
 			uint8_t date_format = 1;			/* 0 = Y/M/D, 1 = M/D/Y, 2 = D/M/Y */
 			uint8_t keyboard = 1;				/* 0 = Japan, 1 = USA, 2 = France, 3 = UK, 4 = Germany, 5 = USSR, 6 = Spain */
 
+			// TODO: CRCs below are incomplete, at best.
 			switch(target.region) {
 				case Target::Region::Japan:
-					rom_names.push_back("msx-japanese.rom");
-					vdp_.set_tv_standard(TI::TMS::TVStandard::NTSC);
+					required_roms.emplace_back(machine_name, "a Japanese MSX BIOS", "msx-japanese.rom", 32*1024, 0xee229390);
+					vdp_->set_tv_standard(TI::TMS::TVStandard::NTSC);
 
 					is_ntsc = true;
 					character_generator = 0;
 					date_format = 0;
 				break;
 				case Target::Region::USA:
-					rom_names.push_back("msx-american.rom");
-					vdp_.set_tv_standard(TI::TMS::TVStandard::NTSC);
+					required_roms.emplace_back(machine_name, "an American MSX BIOS", "msx-american.rom", 32*1024, 0);
+					vdp_->set_tv_standard(TI::TMS::TVStandard::NTSC);
 
 					is_ntsc = true;
 					character_generator = 1;
 					date_format = 1;
 				break;
 				case Target::Region::Europe:
-					rom_names.push_back("msx-european.rom");
-					vdp_.set_tv_standard(TI::TMS::TVStandard::PAL);
+					required_roms.emplace_back(machine_name, "a European MSX BIOS", "msx-european.rom", 32*1024, 0);
+					vdp_->set_tv_standard(TI::TMS::TVStandard::PAL);
 
 					is_ntsc = false;
 					character_generator = 1;
@@ -209,10 +214,12 @@ class ConcreteMachine:
 
 			// Fetch the necessary ROMs; try the region-specific ROM first,
 			// but failing that fall back on patching the main one.
+			size_t disk_index = 0;
 			if(target.has_disk_drive) {
-				rom_names.push_back("disk.rom");
+				disk_index = required_roms.size();
+				required_roms.emplace_back(machine_name, "the MSX-DOS ROM", "disk.rom", 16*1024, 0x721f61df);
 			}
-			const auto roms = rom_fetcher("MSX", rom_names);
+			const auto roms = rom_fetcher(required_roms);
 
 			if((!roms[0] && !roms[1]) || (target.has_disk_drive && !roms[2])) {
 				throw ROMMachine::Error::MissingROMs;
@@ -227,7 +234,6 @@ class ConcreteMachine:
 				memory_slots_[0].source = std::move(*roms[0]);
 				memory_slots_[0].source.resize(32768);
 
-
 				memory_slots_[0].source[0x2b] = uint8_t(
 					(is_ntsc ? 0x00 : 0x80) |
 					(date_format << 4) |
@@ -252,7 +258,7 @@ class ConcreteMachine:
 			// Add a disk cartridge if any disks were supplied.
 			if(target.has_disk_drive) {
 				memory_slots_[2].set_handler(new DiskROM(memory_slots_[2].source));
-				memory_slots_[2].source = std::move(*roms[1]);
+				memory_slots_[2].source = std::move(*roms[disk_index]);
 				memory_slots_[2].source.resize(16384);
 
 				map(2, 0, 0x4000, 0x2000);
@@ -273,11 +279,11 @@ class ConcreteMachine:
 		}
 
 		void set_scan_target(Outputs::Display::ScanTarget *scan_target) override {
-			vdp_.set_scan_target(scan_target);
+			vdp_->set_scan_target(scan_target);
 		}
 
 		void set_display_type(Outputs::Display::DisplayType display_type) override {
-			vdp_.set_display_type(display_type);
+			vdp_->set_display_type(display_type);
 		}
 
 		Outputs::Speaker::Speaker *get_speaker() override {
@@ -406,7 +412,7 @@ class ConcreteMachine:
 			// but otherwise runs without pause.
 			const HalfCycles addition((cycle.operation == CPU::Z80::PartialMachineCycle::ReadOpcode) ? 2 : 0);
 			const HalfCycles total_length = addition + cycle.length;
-			time_since_vdp_update_ += total_length;
+			vdp_ += total_length;
 			time_since_ay_update_ += total_length;
 			memory_slots_[0].cycles_since_update += total_length;
 			memory_slots_[1].cycles_since_update += total_length;
@@ -484,7 +490,7 @@ class ConcreteMachine:
 							*cycle.value = read_pointers_[address >> 13][address & 8191];
 						} else {
 							int slot_hit = (paged_memory_ >> ((address >> 14) * 2)) & 3;
-							memory_slots_[slot_hit].handler->run_for(memory_slots_[slot_hit].cycles_since_update.flush());
+							memory_slots_[slot_hit].handler->run_for(memory_slots_[slot_hit].cycles_since_update.flush<HalfCycles>());
 							*cycle.value = memory_slots_[slot_hit].handler->read(address);
 						}
 					break;
@@ -495,7 +501,7 @@ class ConcreteMachine:
 						int slot_hit = (paged_memory_ >> ((address >> 14) * 2)) & 3;
 						if(memory_slots_[slot_hit].handler) {
 							update_audio();
-							memory_slots_[slot_hit].handler->run_for(memory_slots_[slot_hit].cycles_since_update.flush());
+							memory_slots_[slot_hit].handler->run_for(memory_slots_[slot_hit].cycles_since_update.flush<HalfCycles>());
 							memory_slots_[slot_hit].handler->write(address, *cycle.value, read_pointers_[pc_address_ >> 13] != memory_slots_[0].read_pointers[pc_address_ >> 13]);
 						}
 					} break;
@@ -503,10 +509,9 @@ class ConcreteMachine:
 					case CPU::Z80::PartialMachineCycle::Input:
 						switch(address & 0xff) {
 							case 0x98:	case 0x99:
-								vdp_.run_for(time_since_vdp_update_.flush());
-								*cycle.value = vdp_.get_register(address);
-								z80_.set_interrupt_line(vdp_.get_interrupt_line());
-								time_until_interrupt_ = vdp_.get_time_until_interrupt();
+								*cycle.value = vdp_->get_register(address);
+								z80_.set_interrupt_line(vdp_->get_interrupt_line());
+								time_until_interrupt_ = vdp_->get_time_until_interrupt();
 							break;
 
 							case 0xa2:
@@ -531,10 +536,9 @@ class ConcreteMachine:
 						const int port = address & 0xff;
 						switch(port) {
 							case 0x98:	case 0x99:
-								vdp_.run_for(time_since_vdp_update_.flush());
-								vdp_.set_register(address, *cycle.value);
-								z80_.set_interrupt_line(vdp_.get_interrupt_line());
-								time_until_interrupt_ = vdp_.get_time_until_interrupt();
+								vdp_->set_register(address, *cycle.value);
+								z80_.set_interrupt_line(vdp_->get_interrupt_line());
+								time_until_interrupt_ = vdp_->get_time_until_interrupt();
 							break;
 
 							case 0xa0:	case 0xa1:
@@ -607,7 +611,7 @@ class ConcreteMachine:
 		}
 
 		void flush() {
-			vdp_.run_for(time_since_vdp_update_.flush());
+			vdp_.flush();
 			update_audio();
 			audio_queue_.perform();
 		}
@@ -748,7 +752,7 @@ class ConcreteMachine:
 		};
 
 		CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
-		TI::TMS::TMS9918 vdp_;
+		JustInTimeActor<TI::TMS::TMS9918, HalfCycles> vdp_;
 		Intel::i8255::i8255<i8255PortHandler> i8255_;
 
 		Concurrency::DeferringAsyncTaskQueue audio_queue_;
@@ -792,7 +796,6 @@ class ConcreteMachine:
 		uint8_t scratch_[8192];
 		uint8_t unpopulated_[8192];
 
-		HalfCycles time_since_vdp_update_;
 		HalfCycles time_since_ay_update_;
 		HalfCycles time_until_interrupt_;
 

Machines/MasterSystem/MasterSystem.cpp

@@ -18,6 +18,7 @@
 #include "../KeyboardMachine.hpp"
 
 #include "../../ClockReceiver/ForceInline.hpp"
+#include "../../ClockReceiver/JustInTime.hpp"
 
 #include "../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
 #include "../../Outputs/Log.hpp"
@@ -132,7 +133,12 @@ class ConcreteMachine:
 
 			// Load the BIOS if relevant.
 			if(has_bios()) {
-				const auto roms = rom_fetcher("MasterSystem", {"bios.sms"});
+				// TODO: there's probably a million other versions of the Master System BIOS; try to build a
+				// CRC32 catalogue of those. So far:
+				//
+				//	0072ed54 = US/European BIOS 1.3
+				//	48d44a13 = Japanese BIOS 2.1
+				const auto roms = rom_fetcher({ {"MasterSystem", "the Master System BIOS", "bios.sms", 8*1024, { 0x0072ed54, 0x48d44a13 } } });
 				if(!roms[0]) {
 					// No BIOS found; attempt to boot as though it has already disabled itself.
 					memory_control_ |= 0x08;
@@ -163,16 +169,16 @@ class ConcreteMachine:
 		}
 
 		void set_scan_target(Outputs::Display::ScanTarget *scan_target) override {
-			vdp_.set_tv_standard(
+			vdp_->set_tv_standard(
 				(region_ == Target::Region::Europe) ?
 					TI::TMS::TVStandard::PAL : TI::TMS::TVStandard::NTSC);
-			time_until_debounce_ = vdp_.get_time_until_line(-1);
+			time_until_debounce_ = vdp_->get_time_until_line(-1);
 
-			vdp_.set_scan_target(scan_target);
+			vdp_->set_scan_target(scan_target);
 		}
 
 		void set_display_type(Outputs::Display::DisplayType display_type) override {
-			vdp_.set_display_type(display_type);
+			vdp_->set_display_type(display_type);
 		}
 
 		Outputs::Speaker::Speaker *get_speaker() override {
@@ -184,7 +190,7 @@ class ConcreteMachine:
 		}
 
 		forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
-			time_since_vdp_update_ += cycle.length;
+			vdp_ += cycle.length;
 			time_since_sn76489_update_ += cycle.length;
 
 			if(cycle.is_terminal()) {
@@ -228,17 +234,15 @@ class ConcreteMachine:
 								*cycle.value = 0xff;
 							break;
 							case 0x40:
-								update_video();
-								*cycle.value = vdp_.get_current_line();
+								*cycle.value = vdp_->get_current_line();
 							break;
 							case 0x41:
-								*cycle.value = vdp_.get_latched_horizontal_counter();
+								*cycle.value = vdp_.last_valid()->get_latched_horizontal_counter();
 							break;
 							case 0x80: case 0x81:
-								update_video();
-								*cycle.value = vdp_.get_register(address);
-								z80_.set_interrupt_line(vdp_.get_interrupt_line());
-								time_until_interrupt_ = vdp_.get_time_until_interrupt();
+								*cycle.value = vdp_->get_register(address);
+								z80_.set_interrupt_line(vdp_->get_interrupt_line());
+								time_until_interrupt_ = vdp_->get_time_until_interrupt();
 							break;
 							case 0xc0: {
 								Joystick *const joypad1 = static_cast<Joystick *>(joysticks_[0].get());
@@ -279,8 +283,7 @@ class ConcreteMachine:
 
 								// Latch if either TH has newly gone to 1.
 								if((new_ths^previous_ths)&new_ths) {
-									update_video();
-									vdp_.latch_horizontal_counter();
+									vdp_->latch_horizontal_counter();
 								}
 							} break;
 							case 0x40: case 0x41:
@@ -288,10 +291,9 @@ class ConcreteMachine:
 								sn76489_.set_register(*cycle.value);
 							break;
 							case 0x80: case 0x81:
-								update_video();
-								vdp_.set_register(address, *cycle.value);
-								z80_.set_interrupt_line(vdp_.get_interrupt_line());
-								time_until_interrupt_ = vdp_.get_time_until_interrupt();
+								vdp_->set_register(address, *cycle.value);
+								z80_.set_interrupt_line(vdp_->get_interrupt_line());
+								time_until_interrupt_ = vdp_->get_time_until_interrupt();
 							break;
 							case 0xc0:
 								LOG("TODO: [output] I/O port A/N; " << int(*cycle.value));
@@ -326,15 +328,14 @@ class ConcreteMachine:
 			time_until_debounce_ -= cycle.length;
 			if(time_until_debounce_ <= HalfCycles(0)) {
 				z80_.set_non_maskable_interrupt_line(pause_is_pressed_);
-				update_video();
-				time_until_debounce_ = vdp_.get_time_until_line(-1);
+				time_until_debounce_ = vdp_->get_time_until_line(-1);
 			}
 
 			return HalfCycles(0);
 		}
 
 		void flush() {
-			update_video();
+			vdp_.flush();
 			update_audio();
 			audio_queue_.perform();
 		}
@@ -407,16 +408,13 @@ class ConcreteMachine:
 		inline void update_audio() {
 			speaker_.run_for(audio_queue_, time_since_sn76489_update_.divide_cycles(Cycles(sn76489_divider)));
 		}
-		inline void update_video() {
-			vdp_.run_for(time_since_vdp_update_.flush());
-		}
 
 		using Target = Analyser::Static::Sega::Target;
 		Target::Model model_;
 		Target::Region region_;
 		Target::PagingScheme paging_scheme_;
 		CPU::Z80::Processor<ConcreteMachine, false, false> z80_;
-		TI::TMS::TMS9918 vdp_;
+		JustInTimeActor<TI::TMS::TMS9918, HalfCycles> vdp_;
 
 		Concurrency::DeferringAsyncTaskQueue audio_queue_;
 		TI::SN76489 sn76489_;
@@ -426,7 +424,6 @@ class ConcreteMachine:
 		Inputs::Keyboard keyboard_;
 		bool reset_is_pressed_ = false, pause_is_pressed_ = false;
 
-		HalfCycles time_since_vdp_update_;
 		HalfCycles time_since_sn76489_update_;
 		HalfCycles time_until_interrupt_;
 		HalfCycles time_until_debounce_;

Machines/MouseMachine.hpp

@@ -0,0 +1,23 @@
+//
+//  MouseMachine.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 11/06/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef MouseMachine_hpp
+#define MouseMachine_hpp
+
+#include "../Inputs/Mouse.hpp"
+
+namespace MouseMachine {
+
+class Machine {
+	public:
+		virtual Inputs::Mouse &get_mouse() = 0;
+};
+
+}
+
+#endif /* MouseMachine_hpp */

Machines/Oric/Oric.cpp

@@ -170,7 +170,7 @@ class VIAPortHandler: public MOS::MOS6522::IRQDelegatePortHandler {
 		/*!
 			Advances time. This class manages the AY's concept of time to permit updating-on-demand.
 		*/
-		inline void run_for(const Cycles cycles) {
+		inline void run_for(const HalfCycles cycles) {
 			cycles_since_ay_update_ += cycles;
 		}
 
@@ -182,11 +182,11 @@ class VIAPortHandler: public MOS::MOS6522::IRQDelegatePortHandler {
 
 	private:
 		void update_ay() {
-			speaker_.run_for(audio_queue_, cycles_since_ay_update_.flush());
+			speaker_.run_for(audio_queue_, cycles_since_ay_update_.flush<Cycles>());
 		}
 		bool ay_bdir_ = false;
 		bool ay_bc1_ = false;
-		Cycles cycles_since_ay_update_;
+		HalfCycles cycles_since_ay_update_;
 
 		Concurrency::DeferringAsyncTaskQueue &audio_queue_;
 		GI::AY38910::AY38910 &ay8910_;
@@ -228,19 +228,34 @@ template <Analyser::Static::Oric::Target::DiskInterface disk_interface> class Co
 				diskii_.set_clocking_hint_observer(this);
 			}
 
-			std::vector<std::string> rom_names = {"colour.rom"};
+			const std::string machine_name = "Oric";
+			std::vector<ROMMachine::ROM> rom_names = { {machine_name, "the Oric colour ROM", "colour.rom", 128, 0xd50fca65} };
 			switch(target.rom) {
-				case Analyser::Static::Oric::Target::ROM::BASIC10: rom_names.push_back("basic10.rom");	break;
-				case Analyser::Static::Oric::Target::ROM::BASIC11: rom_names.push_back("basic11.rom");	break;
-				case Analyser::Static::Oric::Target::ROM::Pravetz: rom_names.push_back("pravetz.rom");	break;
+				case Analyser::Static::Oric::Target::ROM::BASIC10:
+					rom_names.emplace_back(machine_name, "Oric BASIC 1.0", "basic10.rom", 16*1024, 0xf18710b4);
+				break;
+				case Analyser::Static::Oric::Target::ROM::BASIC11:
+					rom_names.emplace_back(machine_name, "Oric BASIC 1.1", "basic11.rom", 16*1024, 0xc3a92bef);
+				break;
+				case Analyser::Static::Oric::Target::ROM::Pravetz:
+					rom_names.emplace_back(machine_name, "Pravetz BASIC", "pravetz.rom", 16*1024, 0x58079502);
+				break;
 			}
+			size_t diskii_state_machine_index = 0;
 			switch(disk_interface) {
 				default: break;
-				case Analyser::Static::Oric::Target::DiskInterface::Microdisc:	rom_names.push_back("microdisc.rom");	break;
-				case Analyser::Static::Oric::Target::DiskInterface::Pravetz:	rom_names.push_back("8dos.rom");		break;
+				case Analyser::Static::Oric::Target::DiskInterface::Microdisc:
+					rom_names.emplace_back(machine_name, "the ORIC Microdisc ROM", "microdisc.rom", 8*1024, 0xa9664a9c);
+				break;
+				case Analyser::Static::Oric::Target::DiskInterface::Pravetz:
+					rom_names.emplace_back(machine_name, "the 8DOS boot ROM", "8dos.rom", 512, 0x49a74c06);
+					// These ROM details are coupled with those in the DiskIICard.
+					diskii_state_machine_index = rom_names.size();
+					rom_names.push_back({"DiskII", "the Disk II 16-sector state machine ROM", "state-machine-16.rom", 256, { 0x9796a238, 0xb72a2c70 }});
+				break;
 			}
 
-			const auto roms = rom_fetcher("Oric", rom_names);
+			const auto roms = rom_fetcher(rom_names);
 
 			for(std::size_t index = 0; index < roms.size(); ++index) {
 				if(!roms[index]) {
@@ -261,11 +276,7 @@ template <Analyser::Static::Oric::Target::DiskInterface disk_interface> class Co
 					pravetz_rom_ = std::move(*roms[2]);
 					pravetz_rom_.resize(512);
 
-					auto state_machine_rom = rom_fetcher("DiskII", {"state-machine-16.rom"});
-					if(!state_machine_rom[0]) {
-						throw ROMMachine::Error::MissingROMs;
-					}
-					diskii_.set_state_machine(*state_machine_rom[0]);
+					diskii_.set_state_machine(*roms[diskii_state_machine_index]);
 				} break;
 			}
 
@@ -434,7 +445,6 @@ template <Analyser::Static::Oric::Target::DiskInterface disk_interface> class Co
 			}
 
 			via_.run_for(Cycles(1));
-			via_port_handler_.run_for(Cycles(1));
 			tape_player_.run_for(Cycles(1));
 			switch(disk_interface) {
 				default: break;
@@ -456,7 +466,7 @@ template <Analyser::Static::Oric::Target::DiskInterface disk_interface> class Co
 
 		forceinline void flush() {
 			update_video();
-			via_port_handler_.flush();
+			via_.flush();
 			flush_diskii();
 		}
 
@@ -575,7 +585,7 @@ template <Analyser::Static::Oric::Target::DiskInterface disk_interface> class Co
 		uint8_t ram_[65536];
 		Cycles cycles_since_video_update_;
 		inline void update_video() {
-			video_output_.run_for(cycles_since_video_update_.flush());
+			video_output_.run_for(cycles_since_video_update_.flush<Cycles>());
 		}
 
 		// ROM bookkeeping
@@ -607,7 +617,7 @@ template <Analyser::Static::Oric::Target::DiskInterface disk_interface> class Co
 		Apple::DiskII diskii_;
 		Cycles cycles_since_diskii_update_;
 		void flush_diskii() {
-			diskii_.run_for(cycles_since_diskii_update_.flush());
+			diskii_.run_for(cycles_since_diskii_update_.flush<Cycles>());
 		}
 		std::vector<uint8_t> pravetz_rom_;
 		std::size_t pravetz_rom_base_pointer_ = 0;

Machines/ROMMachine.hpp

@@ -16,15 +16,41 @@
 
 namespace ROMMachine {
 
+/*!
+	Describes a ROM image; this term is used in this emulator strictly in the sense of firmware —
+	system software that is an inherent part of a machine.
+*/
+struct ROM {
+	/// The machine with which this ROM is associated, in a form that is safe for using as
+	/// part of a file name.
+	std::string machine_name;
+	/// A descriptive name for this ROM, suitable for use in a bullet-point list, a bracket
+	/// clause, etc, e.g. "the Electron MOS 1.0".
+	std::string descriptive_name;
+	/// An idiomatic file name for this ROM, e.g. "os10.rom".
+	std::string file_name;
+	/// The expected size of this ROM in bytes, e.g. 32768.
+	size_t size = 0;
+	/// CRC32s for all known acceptable copies of this ROM; intended to allow a host platform
+	/// to test user-provided ROMs of unknown provenance. **Not** intended to be used
+	/// to exclude ROMs where the user's intent is otherwise clear.
+	std::vector<uint32_t> crc32s;
+
+	ROM(std::string machine_name, std::string descriptive_name, std::string file_name, size_t size, uint32_t crc32) :
+		machine_name(machine_name), descriptive_name(descriptive_name), file_name(file_name), size(size), crc32s({crc32}) {}
+	ROM(std::string machine_name, std::string descriptive_name, std::string file_name, size_t size, std::initializer_list<uint32_t> crc32s) :
+		machine_name(machine_name), descriptive_name(descriptive_name), file_name(file_name), size(size), crc32s(crc32s) {}
+};
+
 /*!
 	Defines the signature for a function that must be supplied by the host environment in order to give machines
 	a route for fetching any system ROMs they might need.
 
-	The caller will supply the idiomatic name of the machine plus a vector of the names of ROM files that it expects
-	to be present. The recevier should return a vector of unique_ptrs that either contain the contents of the
-	ROM from @c names that corresponds by index, or else are the nullptr
+	The caller will supply a vector of the names of ROM files that it would like to inspect. The recevier should
+	return a vector of unique_ptrs that either contain the contents of the ROM from @c names that corresponds by
+	index, or else are @c nullptr.
 */
-typedef std::function<std::vector<std::unique_ptr<std::vector<uint8_t>>>(const std::string &machine, const std::vector<std::string> &names)> ROMFetcher;
+typedef std::function<std::vector<std::unique_ptr<std::vector<uint8_t>>>(const std::vector<ROM> &roms)> ROMFetcher;
 
 enum class Error {
 	MissingROMs

Machines/Utility/MachineForTarget.cpp

@@ -9,7 +9,8 @@
 #include "MachineForTarget.hpp"
 
 #include "../AmstradCPC/AmstradCPC.hpp"
-#include "../AppleII/AppleII.hpp"
+#include "../Apple/AppleII/AppleII.hpp"
+#include "../Apple/Macintosh/Macintosh.hpp"
 #include "../Atari2600/Atari2600.hpp"
 #include "../ColecoVision/ColecoVision.hpp"
 #include "../Commodore/Vic-20/Vic20.hpp"
@@ -33,14 +34,15 @@ namespace {
 #define Bind(m)	BindD(m, m)
 		switch(target->machine) {
 			Bind(AmstradCPC)
-			Bind(AppleII)
+			BindD(Apple::II, AppleII)
+			BindD(Apple::Macintosh, Macintosh)
 			Bind(Atari2600)
 			BindD(Coleco::Vision, ColecoVision)
+			BindD(Commodore::Vic20, Vic20)
 			Bind(Electron)
-			BindD(Sega::MasterSystem, MasterSystem)
 			Bind(MSX)
 			Bind(Oric)
-			BindD(Commodore::Vic20, Vic20)
+			BindD(Sega::MasterSystem, MasterSystem)
 			Bind(ZX8081)
 
 			default:
@@ -103,6 +105,7 @@ std::string Machine::ShortNameForTargetMachine(const Analyser::Machine machine)
 		case Analyser::Machine::Atari2600:		return "Atari2600";
 		case Analyser::Machine::ColecoVision:	return "ColecoVision";
 		case Analyser::Machine::Electron:		return "Electron";
+		case Analyser::Machine::Macintosh:		return "Macintosh";
 		case Analyser::Machine::MSX:			return "MSX";
 		case Analyser::Machine::Oric:			return "Oric";
 		case Analyser::Machine::Vic20:			return "Vic20";
@@ -119,6 +122,7 @@ std::string Machine::LongNameForTargetMachine(Analyser::Machine machine) {
 		case Analyser::Machine::Atari2600:		return "Atari 2600";
 		case Analyser::Machine::ColecoVision:	return "ColecoVision";
 		case Analyser::Machine::Electron:		return "Acorn Electron";
+		case Analyser::Machine::Macintosh:		return "Apple Macintosh";
 		case Analyser::Machine::MSX:			return "MSX";
 		case Analyser::Machine::Oric:			return "Oric";
 		case Analyser::Machine::Vic20:			return "Vic 20";
@@ -132,7 +136,8 @@ std::map<std::string, std::vector<std::unique_ptr<Configurable::Option>>> Machin
 	std::map<std::string, std::vector<std::unique_ptr<Configurable::Option>>> options;
 
 	options.emplace(std::make_pair(LongNameForTargetMachine(Analyser::Machine::AmstradCPC), AmstradCPC::get_options()));
-	options.emplace(std::make_pair(LongNameForTargetMachine(Analyser::Machine::AppleII), AppleII::get_options()));
+	options.emplace(std::make_pair(LongNameForTargetMachine(Analyser::Machine::AppleII), Apple::II::get_options()));
+	options.emplace(std::make_pair(LongNameForTargetMachine(Analyser::Machine::ColecoVision), Coleco::Vision::get_options()));
 	options.emplace(std::make_pair(LongNameForTargetMachine(Analyser::Machine::Electron), Electron::get_options()));
 	options.emplace(std::make_pair(LongNameForTargetMachine(Analyser::Machine::MSX), MSX::get_options()));
 	options.emplace(std::make_pair(LongNameForTargetMachine(Analyser::Machine::Oric), Oric::get_options()));

Machines/Utility/MemoryFuzzer.cpp

@@ -23,6 +23,10 @@ void Memory::Fuzz(uint8_t *buffer, std::size_t size) {
 	}
 }
 
+void Memory::Fuzz(uint16_t *buffer, std::size_t size) {
+	Fuzz(reinterpret_cast<uint8_t *>(buffer), size * sizeof(uint16_t));
+}
+
 void Memory::Fuzz(std::vector<uint8_t> &buffer) {
 	Fuzz(buffer.data(), buffer.size());
 }

Machines/Utility/MemoryFuzzer.hpp

@@ -18,7 +18,10 @@ namespace Memory {
 /// Stores @c size random bytes from @c buffer onwards.
 void Fuzz(uint8_t *buffer, std::size_t size);
 
-// Replaces all existing vector contents with random bytes.
+/// Stores @c size random 16-bit words from @c buffer onwards.
+void Fuzz(uint16_t *buffer, std::size_t size);
+
+/// Replaces all existing vector contents with random bytes.
 void Fuzz(std::vector<uint8_t> &buffer);
 
 }

Machines/Utility/MemoryPacker.cpp

@@ -0,0 +1,15 @@
+//
+//  MemoryPacker.cpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 03/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#include "MemoryPacker.hpp"
+
+void Memory::PackBigEndian16(const std::vector<uint8_t> &source, uint16_t *target) {
+	for(std::size_t c = 0; c < source.size(); c += 2) {
+		target[c >> 1] = uint16_t(source[c] << 8) | uint16_t(source[c+1]);
+	}
+}

Machines/Utility/MemoryPacker.hpp

@@ -0,0 +1,24 @@
+//
+//  MemoryPacker.hpp
+//  Clock Signal
+//
+//  Created by Thomas Harte on 03/05/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#ifndef MemoryPacker_hpp
+#define MemoryPacker_hpp
+
+#include <cstdint>
+#include <vector>
+
+namespace Memory {
+
+/*!
+	Copies the bytes from @c source into @c target, interpreting them
+	as big-endian 16-bit data.
+*/
+void PackBigEndian16(const std::vector<uint8_t> &source, uint16_t *target);
+
+}
+#endif /* MemoryPacker_hpp */

Machines/Utility/TypedDynamicMachine.hpp

@@ -45,6 +45,10 @@ template<typename T> class TypedDynamicMachine: public ::Machine::DynamicMachine
 			return get<KeyboardMachine::Machine>();
 		}
 
+		MouseMachine::Machine *mouse_machine() override {
+			return get<MouseMachine::Machine>();
+		}
+
 		Configurable::Device *configurable_device() override {
 			return get<Configurable::Device>();
 		}

Machines/ZX8081/ZX8081.cpp

@@ -76,7 +76,11 @@ template<bool is_zx81> class ConcreteMachine:
 			clear_all_keys();
 
 			const bool use_zx81_rom = target.is_ZX81 || target.ZX80_uses_ZX81_ROM;
-			const auto roms = rom_fetcher("ZX8081", { use_zx81_rom ? "zx81.rom" : "zx80.rom" });
+			const auto roms =
+				use_zx81_rom ?
+					rom_fetcher({ {"ZX8081", "the ZX81 BASIC ROM", "zx81.rom", 8 * 1024, 0x4b1dd6eb} }) :
+					rom_fetcher({ {"ZX8081", "the ZX80 BASIC ROM", "zx80.rom", 4 * 1024, 0x4c7fc597} });
+
 			if(!roms[0]) throw ROMMachine::Error::MissingROMs;
 
 			rom_ = std::move(*roms[0]);

OSBindings/Mac/Clock Signal.xcodeproj/project.xcworkspace/contents.xcworkspacedata

@@ -1,6 +1,9 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Workspace
    version = "1.0">
+   <FileRef
+      location = "group:/Users/thomasharte/Projects/CLK/OSBindings/Mac/Clock SignalTests/68000ArithmeticTests.mm">
+   </FileRef>
    <FileRef
       location = "self:Clock Signal.xcodeproj">
    </FileRef>

OSBindings/Mac/Clock Signal.xcodeproj/xcshareddata/xcschemes/Clock Signal.xcscheme

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <Scheme
-   LastUpgradeVersion = "0930"
+   LastUpgradeVersion = "1030"
    version = "1.3">
    <BuildAction
       parallelizeBuildables = "YES"
@@ -26,6 +26,7 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      disableMainThreadChecker = "YES"
       codeCoverageEnabled = "YES"
       shouldUseLaunchSchemeArgsEnv = "YES">
       <Testables>
@@ -68,7 +69,7 @@
       </AdditionalOptions>
    </TestAction>
    <LaunchAction
-      buildConfiguration = "Release"
+      buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
       enableASanStackUseAfterReturn = "YES"

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

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="14113" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="14490.70" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="14113"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="14490.70"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
@@ -14,7 +14,7 @@
         </customObject>
         <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
         <customObject id="-3" userLabel="Application" customClass="NSObject"/>
-        <window title="Window" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" oneShot="NO" releasedWhenClosed="NO" showsToolbarButton="NO" visibleAtLaunch="NO" animationBehavior="default" id="xOd-HO-29H" userLabel="Window">
+        <window title="Window" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" id="xOd-HO-29H" userLabel="Window">
             <windowStyleMask key="styleMask" titled="YES" closable="YES" miniaturizable="YES" resizable="YES"/>
             <windowCollectionBehavior key="collectionBehavior" fullScreenPrimary="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
@@ -25,7 +25,7 @@
                 <rect key="frame" x="0.0" y="0.0" width="600" height="450"/>
                 <autoresizingMask key="autoresizingMask"/>
                 <subviews>
-                    <openGLView hidden="YES" useAuxiliaryDepthBufferStencil="NO" allowOffline="YES" wantsBestResolutionOpenGLSurface="YES" translatesAutoresizingMaskIntoConstraints="NO" id="DEG-fq-cjd" customClass="CSOpenGLView">
+                    <openGLView hidden="YES" wantsLayer="YES" useAuxiliaryDepthBufferStencil="NO" allowOffline="YES" wantsBestResolutionOpenGLSurface="YES" translatesAutoresizingMaskIntoConstraints="NO" id="DEG-fq-cjd" customClass="CSOpenGLView">
                         <rect key="frame" x="0.0" y="0.0" width="600" height="450"/>
                     </openGLView>
                 </subviews>
@@ -36,6 +36,11 @@
                     <constraint firstItem="DEG-fq-cjd" firstAttribute="width" secondItem="gIp-Ho-8D9" secondAttribute="width" id="mYS-bH-DST"/>
                 </constraints>
             </view>
+            <userDefinedRuntimeAttributes>
+                <userDefinedRuntimeAttribute type="color" keyPath="backgroundColor">
+                    <color key="value" white="0.0" alpha="1" colorSpace="custom" customColorSpace="genericGamma22GrayColorSpace"/>
+                </userDefinedRuntimeAttribute>
+            </userDefinedRuntimeAttributes>
             <connections>
                 <outlet property="delegate" destination="-2" id="0bl-1N-x8E"/>
                 <outlet property="initialFirstResponder" destination="DEG-fq-cjd" id="9RI-Kx-QeN"/>

OSBindings/Mac/Clock Signal/ClockSignal-Bridging-Header.h

@@ -10,10 +10,13 @@
 
 #import "CSStaticAnalyser.h"
 
-#import	"CSOpenGLView.h"
 #import "CSAudioQueue.h"
+#import	"CSOpenGLView.h"
+#import "CSROMReceiverView.h"
 
 #import "CSBestEffortUpdater.h"
 #import "CSJoystickManager.h"
 
+#import "NSData+CRC32.h"
+
 #include "KeyCodes.h"

OSBindings/Mac/Clock Signal/Documents/MachineDocument.swift

@@ -16,109 +16,76 @@ class MachineDocument:
 	CSOpenGLViewDelegate,
 	CSOpenGLViewResponderDelegate,
 	CSBestEffortUpdaterDelegate,
-	CSAudioQueueDelegate
+	CSAudioQueueDelegate,
+	CSROMReciverViewDelegate
 {
-	fileprivate let actionLock = NSLock()
-	fileprivate let drawLock = NSLock()
-	fileprivate let bestEffortLock = NSLock()
+	// MARK: - Mutual Exclusion.
 
-	var machine: CSMachine!
-	var name: String! {
-		get {
-			return nil
-		}
-	}
-	var optionsPanelNibName: String?
+	/// Ensures exclusive access between calls to self.machine.run and close().
+	private let actionLock = NSLock()
+	/// Ensures exclusive access between calls to machine.updateView and machine.drawView, and close().
+	private let drawLock = NSLock()
+	/// Ensures exclusive access to the best-effort updater.
+	private let bestEffortLock = NSLock()
 
-	func aspectRatio() -> NSSize {
+	// MARK: - Machine details.
+
+	/// A description of the machine this document should represent once fully set up.
+	private var machineDescription: CSStaticAnalyser?
+
+	/// The active machine, following its successful creation.
+	private var machine: CSMachine!
+
+	/// @returns the appropriate window content aspect ratio for this @c self.machine.
+	private func aspectRatio() -> NSSize {
 		return NSSize(width: 4.0, height: 3.0)
 	}
 
+	/// The output audio queue, if any.
+	private var audioQueue: CSAudioQueue!
+
+	/// The best-effort updater.
+	private var bestEffortUpdater: CSBestEffortUpdater?
+
+	// MARK: - Main NIB connections.
+
+	/// The OpenGL view to receive this machine's display.
 	@IBOutlet weak var openGLView: CSOpenGLView!
+
+	/// The options panel, if any.
 	@IBOutlet var optionsPanel: MachinePanel!
+
+	/// An action to display the options panel, if there is one.
 	@IBAction func showOptions(_ sender: AnyObject!) {
 		optionsPanel?.setIsVisible(true)
 	}
 
+	/// The activity panel, if one is deemed appropriate.
 	@IBOutlet var activityPanel: NSPanel!
+
+	/// An action to display the activity panel, if there is one.
 	@IBAction func showActivity(_ sender: AnyObject!) {
 		activityPanel.setIsVisible(true)
 	}
 
-	fileprivate var audioQueue: CSAudioQueue! = nil
-	fileprivate var bestEffortUpdater: CSBestEffortUpdater?
+	// MARK: - NSDocument Overrides and NSWindowDelegate methods.
 
+	/// Links this class to the MachineDocument NIB.
 	override var windowNibName: NSNib.Name? {
-		return NSNib.Name(rawValue: "MachineDocument")
+		return "MachineDocument"
 	}
 
-	override func windowControllerDidLoadNib(_ aController: NSWindowController) {
-		super.windowControllerDidLoadNib(aController)
-		aController.window?.contentAspectRatio = self.aspectRatio()
-		setupMachineOutput()
+	convenience init(type typeName: String) throws {
+		self.init()
+		self.fileType = typeName
 	}
 
-	// Attempting to show a sheet before the window is visible (such as when the NIB is loaded) results in
-	// a sheet mysteriously floating on its own. For now, use windowDidUpdate as a proxy to know that the window
-	// is visible, though it's a little premature.
-	func windowDidUpdate(_ notification: Notification) {
-		if self.shouldShowNewMachinePanel {
-			self.shouldShowNewMachinePanel = false
-			Bundle.main.loadNibNamed(NSNib.Name(rawValue: "MachinePicker"), owner: self, topLevelObjects: nil)
-			self.machinePicker?.establishStoredOptions()
-			self.windowControllers[0].window?.beginSheet(self.machinePickerPanel!, completionHandler: nil)
-		}
-	}
-
-	fileprivate func setupMachineOutput() {
-		if let machine = self.machine, let openGLView = self.openGLView {
-			// establish the output aspect ratio and audio
-			let aspectRatio = self.aspectRatio()
-			openGLView.perform(glContext: {
-				machine.setView(openGLView, aspectRatio: Float(aspectRatio.width / aspectRatio.height))
-			})
-
-			// attach an options panel if one is available
-			if let optionsPanelNibName = self.optionsPanelNibName {
-				Bundle.main.loadNibNamed(NSNib.Name(rawValue: optionsPanelNibName), owner: self, topLevelObjects: nil)
-				self.optionsPanel.machine = machine
-				self.optionsPanel?.establishStoredOptions()
-				showOptions(self)
-			}
-
-			machine.delegate = self
-			self.bestEffortUpdater = CSBestEffortUpdater()
-
-			// callbacks from the OpenGL may come on a different thread, immediately following the .delegate set;
-			// hence the full setup of the best-effort updater prior to setting self as a delegate
-			openGLView.delegate = self
-			openGLView.responderDelegate = self
-
-			setupAudioQueueClockRate()
-
-			// bring OpenGL view-holding window on top of the options panel and show the content
-			openGLView.isHidden = false
-			openGLView.window!.makeKeyAndOrderFront(self)
-			openGLView.window!.makeFirstResponder(openGLView)
-
-			// start accepting best effort updates
-			self.bestEffortUpdater!.delegate = self
-		}
-	}
-
-	func machineSpeakerDidChangeInputClock(_ machine: CSMachine) {
-		setupAudioQueueClockRate()
-	}
-
-	fileprivate func setupAudioQueueClockRate() {
-		// establish and provide the audio queue, taking advice as to an appropriate sampling rate
-		let maximumSamplingRate = CSAudioQueue.preferredSamplingRate()
-		let selectedSamplingRate = self.machine.idealSamplingRate(from: NSRange(location: 0, length: NSInteger(maximumSamplingRate)))
-		if selectedSamplingRate > 0 {
-			audioQueue = CSAudioQueue(samplingRate: Float64(selectedSamplingRate))
-			audioQueue.delegate = self
-			self.machine.audioQueue = self.audioQueue
-			self.machine.setAudioSamplingRate(selectedSamplingRate, bufferSize:audioQueue.preferredBufferSize)
+	override func read(from url: URL, ofType typeName: String) throws {
+		if let analyser = CSStaticAnalyser(fileAt: url) {
+			self.displayName = analyser.displayName
+			self.configureAs(analyser)
+		} else {
+			throw NSError(domain: "MachineDocument", code: -1, userInfo: nil)
 		}
 	}
 
@@ -148,75 +115,176 @@ class MachineDocument:
 		super.close()
 	}
 
-	// MARK: configuring
+	override func data(ofType typeName: String) throws -> Data {
+		throw NSError(domain: NSOSStatusErrorDomain, code: unimpErr, userInfo: nil)
+	}
+
+	override func windowControllerDidLoadNib(_ aController: NSWindowController) {
+		super.windowControllerDidLoadNib(aController)
+		aController.window?.contentAspectRatio = self.aspectRatio()
+	}
+
+	private var missingROMs: [CSMissingROM] = []
 	func configureAs(_ analysis: CSStaticAnalyser) {
-		if let machine = CSMachine(analyser: analysis) {
+		self.machineDescription = analysis
+
+		let missingROMs = NSMutableArray()
+		if let machine = CSMachine(analyser: analysis, missingROMs: missingROMs) {
 			self.machine = machine
-			self.optionsPanelNibName = analysis.optionsPanelNibName
 			setupMachineOutput()
 			setupActivityDisplay()
-		}
-	}
-
-	fileprivate var shouldShowNewMachinePanel = false
-	override func read(from url: URL, ofType typeName: String) throws {
-		if let analyser = CSStaticAnalyser(fileAt: url) {
-			self.displayName = analyser.displayName
-			self.configureAs(analyser)
 		} else {
-			throw NSError(domain: "MachineDocument", code: -1, userInfo: nil)
+			// Store the selected machine and list of missing ROMs, and
+			// show the missing ROMs dialogue.
+			self.missingROMs = []
+			for untypedMissingROM in missingROMs {
+				self.missingROMs.append(untypedMissingROM as! CSMissingROM)
+			}
+
+			requestRoms()
 		}
 	}
 
-	convenience init(type typeName: String) throws {
-		self.init()
-		self.fileType = typeName
-		self.shouldShowNewMachinePanel = true
+	enum InteractionMode {
+		case notStarted, showingMachinePicker, showingROMRequester, showingMachine
 	}
+	private var interactionMode: InteractionMode = .notStarted
 
-	// MARK: the pasteboard
-	func paste(_ sender: Any) {
-		let pasteboard = NSPasteboard.general
-		if let string = pasteboard.string(forType: .string) {
-			self.machine.paste(string)
+	// Attempting to show a sheet before the window is visible (such as when the NIB is loaded) results in
+	// a sheet mysteriously floating on its own. For now, use windowDidUpdate as a proxy to know that the window
+	// is visible, though it's a little premature.
+	func windowDidUpdate(_ notification: Notification) {
+		// If an interaction mode is not yet in effect, pick the proper one and display the relevant thing.
+		if self.interactionMode == .notStarted {
+			// If a full machine exists, just continue showing it.
+			if self.machine != nil {
+				self.interactionMode = .showingMachine
+				setupMachineOutput()
+				return
+			}
+
+			// If a machine has been picked but is not showing, there must be ROMs missing.
+			if self.machineDescription != nil {
+				self.interactionMode = .showingROMRequester
+				requestRoms()
+				return
+			}
+
+			// If a machine hasn't even been picked yet, show the machine picker.
+			self.interactionMode = .showingMachinePicker
+			Bundle.main.loadNibNamed("MachinePicker", owner: self, topLevelObjects: nil)
+			self.machinePicker?.establishStoredOptions()
+			self.windowControllers[0].window?.beginSheet(self.machinePickerPanel!, completionHandler: nil)
 		}
 	}
 
-	// MARK: CSBestEffortUpdaterDelegate
-	final func bestEffortUpdater(_ bestEffortUpdater: CSBestEffortUpdater!, runForInterval duration: TimeInterval, didSkipPreviousUpdate: Bool) {
-		if actionLock.try() {
-			self.machine.run(forInterval: duration)
-			actionLock.unlock()
+	// MARK: - Connections Between Machine and the Outside World
+
+	private func setupMachineOutput() {
+		if let machine = self.machine, let openGLView = self.openGLView {
+			// Establish the output aspect ratio and audio.
+			let aspectRatio = self.aspectRatio()
+			openGLView.perform(glContext: {
+				machine.setView(openGLView, aspectRatio: Float(aspectRatio.width / aspectRatio.height))
+			})
+
+			// Attach an options panel if one is available.
+			if let optionsPanelNibName = self.machineDescription?.optionsPanelNibName {
+				Bundle.main.loadNibNamed(optionsPanelNibName, owner: self, topLevelObjects: nil)
+				self.optionsPanel.machine = machine
+				self.optionsPanel?.establishStoredOptions()
+				showOptions(self)
+			}
+
+			machine.delegate = self
+			self.bestEffortUpdater = CSBestEffortUpdater()
+
+			// Callbacks from the OpenGL may come on a different thread, immediately following the .delegate set;
+			// hence the full setup of the best-effort updater prior to setting self as a delegate.
+			openGLView.delegate = self
+			openGLView.responderDelegate = self
+
+			// If this machine has a mouse, enable mouse capture.
+			openGLView.shouldCaptureMouse = machine.hasMouse
+
+			setupAudioQueueClockRate()
+
+			// Bring OpenGL view-holding window on top of the options panel and show the content.
+			openGLView.isHidden = false
+			openGLView.window!.makeKeyAndOrderFront(self)
+			openGLView.window!.makeFirstResponder(openGLView)
+
+			// Start accepting best effort updates.
+			self.bestEffortUpdater!.delegate = self
 		}
 	}
 
-	// MARK: CSAudioQueueDelegate
+	func machineSpeakerDidChangeInputClock(_ machine: CSMachine) {
+		setupAudioQueueClockRate()
+	}
+
+	private func setupAudioQueueClockRate() {
+		// establish and provide the audio queue, taking advice as to an appropriate sampling rate
+		let maximumSamplingRate = CSAudioQueue.preferredSamplingRate()
+		let selectedSamplingRate = self.machine.idealSamplingRate(from: NSRange(location: 0, length: NSInteger(maximumSamplingRate)))
+		if selectedSamplingRate > 0 {
+			audioQueue = CSAudioQueue(samplingRate: Float64(selectedSamplingRate))
+			audioQueue.delegate = self
+			self.machine.audioQueue = self.audioQueue
+			self.machine.setAudioSamplingRate(selectedSamplingRate, bufferSize:audioQueue.preferredBufferSize)
+		}
+	}
+
+	/// Responds to the CSAudioQueueDelegate dry-queue warning message by requesting a machine update.
 	final func audioQueueIsRunningDry(_ audioQueue: CSAudioQueue) {
 		bestEffortLock.lock()
 		bestEffortUpdater?.update()
 		bestEffortLock.unlock()
 	}
 
-	// MARK: CSOpenGLViewDelegate
+	/// Responds to the CSOpenGLViewDelegate redraw message by requesting a machine update if this is a timed
+	/// request, and ordering a redraw regardless of the motivation.
 	final func openGLViewRedraw(_ view: CSOpenGLView, event redrawEvent: CSOpenGLViewRedrawEvent) {
-		switch redrawEvent {
-			case .timer:
-				bestEffortLock.lock()
-				if let bestEffortUpdater = bestEffortUpdater {
-					bestEffortLock.unlock()
-					bestEffortUpdater.update()
-				} else {
-					bestEffortLock.unlock()
-				}
-				self.machine.updateView(forPixelSize: view.backingSize)
-				fallthrough
+		if redrawEvent == .timer {
+			bestEffortLock.lock()
+			if let bestEffortUpdater = bestEffortUpdater {
+				bestEffortLock.unlock()
+				bestEffortUpdater.update()
+			} else {
+				bestEffortLock.unlock()
+			}
+		}
 
-			case .appKit:
-				self.machine.drawView(forPixelSize: view.backingSize)
+		if drawLock.try() {
+			if redrawEvent == .timer {
+				machine.updateView(forPixelSize: view.backingSize)
+			}
+			machine.drawView(forPixelSize: view.backingSize)
+			drawLock.unlock()
 		}
 	}
 
-	// MARK: Runtime media insertion.
+	/// Responds to CSBestEffortUpdaterDelegate update message by running the machine.
+	final func bestEffortUpdater(_ bestEffortUpdater: CSBestEffortUpdater!, runForInterval duration: TimeInterval, didSkipPreviousUpdate: Bool) {
+		if let machine = self.machine, actionLock.try() {
+			machine.run(forInterval: duration)
+			actionLock.unlock()
+		}
+	}
+
+	// MARK: - Pasteboard Forwarding.
+
+	/// Forwards any text currently on the pasteboard into the active machine.
+	func paste(_ sender: Any) {
+		let pasteboard = NSPasteboard.general
+		if let string = pasteboard.string(forType: .string), let machine = self.machine {
+			machine.paste(string)
+		}
+	}
+
+	// MARK: - Runtime Media Insertion.
+
+	/// Delegate message to receive drag and drop files.
 	final func openGLView(_ view: CSOpenGLView, didReceiveFileAt URL: URL) {
 		let mediaSet = CSMediaSet(fileAt: URL)
 		if let mediaSet = mediaSet {
@@ -224,6 +292,8 @@ class MachineDocument:
 		}
 	}
 
+	/// Action for the insert menu command; displays an NSOpenPanel and then segues into the same process
+	/// as if a file had been received via drag and drop.
 	@IBAction final func insertMedia(_ sender: AnyObject!) {
 		let openPanel = NSOpenPanel()
 		openPanel.message = "Hint: you can also insert media by dragging and dropping it onto the machine's window."
@@ -239,37 +309,40 @@ class MachineDocument:
 		}
 	}
 
-	// MARK: NSDocument overrides
-	override func data(ofType typeName: String) throws -> Data {
-		throw NSError(domain: NSOSStatusErrorDomain, code: unimpErr, userInfo: nil)
-	}
+	// MARK: - Input Management.
 
-	// MARK: Input management
+	/// Upon a resign key, immediately releases all ongoing input mechanisms — any currently pressed keys,
+	/// and joystick and mouse inputs.
 	func windowDidResignKey(_ notification: Notification) {
 		if let machine = self.machine {
 			machine.clearAllKeys()
 			machine.joystickManager = nil
 		}
+		self.openGLView.releaseMouse()
 	}
 
+	/// Upon becoming key, attaches joystick input to the machine.
 	func windowDidBecomeKey(_ notification: Notification) {
 		if let machine = self.machine {
 			machine.joystickManager = (DocumentController.shared as! DocumentController).joystickManager
 		}
 	}
 
+	/// Forwards key down events directly to the machine.
 	func keyDown(_ event: NSEvent) {
 		if let machine = self.machine {
 			machine.setKey(event.keyCode, characters: event.characters, isPressed: true)
 		}
 	}
 
+	/// Forwards key up events directly to the machine.
 	func keyUp(_ event: NSEvent) {
 		if let machine = self.machine {
 			machine.setKey(event.keyCode, characters: event.characters, isPressed: false)
 		}
 	}
 
+	/// Synthesies appropriate key up and key down events upon any change in modifiers.
 	func flagsChanged(_ newModifiers: NSEvent) {
 		if let machine = self.machine {
 			machine.setKey(VK_Shift, characters: nil, isPressed: newModifiers.modifierFlags.contains(.shift))
@@ -279,19 +352,199 @@ class MachineDocument:
 		}
 	}
 
-	// MARK: New machine creation
+	/// Forwards mouse movement events to the mouse.
+	func mouseMoved(_ event: NSEvent) {
+		if let machine = self.machine {
+			machine.addMouseMotionX(event.deltaX, y: event.deltaY)
+		}
+	}
+
+	/// Forwards mouse button down events to the mouse.
+	func mouseUp(_ event: NSEvent) {
+		if let machine = self.machine {
+			machine.setMouseButton(Int32(event.buttonNumber), isPressed: false)
+		}
+	}
+
+	/// Forwards mouse button up events to the mouse.
+	func mouseDown(_ event: NSEvent) {
+		if let machine = self.machine {
+			machine.setMouseButton(Int32(event.buttonNumber), isPressed: true)
+		}
+	}
+
+	// MARK: - MachinePicker Outlets and Actions
 	@IBOutlet var machinePicker: MachinePicker?
 	@IBOutlet var machinePickerPanel: NSWindow?
 	@IBAction func createMachine(_ sender: NSButton?) {
-		self.configureAs(machinePicker!.selectedMachine())
-		machinePicker = nil
+		let selectedMachine = machinePicker!.selectedMachine()
 		self.windowControllers[0].window?.endSheet(self.machinePickerPanel!)
+		self.machinePicker = nil
+		self.configureAs(selectedMachine)
 	}
 
 	@IBAction func cancelCreateMachine(_ sender: NSButton?) {
 		close()
 	}
 
+	// MARK: - ROMRequester Outlets and Actions
+	@IBOutlet var romRequesterPanel: NSWindow?
+	@IBOutlet var romRequesterText: NSTextField?
+	@IBOutlet var romReceiverErrorField: NSTextField?
+	@IBOutlet var romReceiverView: CSROMReceiverView?
+	private var romRequestBaseText = ""
+	func requestRoms() {
+		// Don't act yet if there's no window controller yet.
+		if self.windowControllers.count == 0 {
+			return
+		}
+
+		// Load the ROM requester dialogue.
+		Bundle.main.loadNibNamed("ROMRequester", owner: self, topLevelObjects: nil)
+		self.romReceiverView!.delegate = self
+		self.romRequestBaseText = romRequesterText!.stringValue
+		romReceiverErrorField?.alphaValue = 0.0
+
+		// Populate the current absentee list.
+		populateMissingRomList()
+
+		// Show the thing.
+		self.windowControllers[0].window?.beginSheet(self.romRequesterPanel!, completionHandler: nil)
+	}
+
+	@IBAction func cancelRequestROMs(_ sender: NSButton?) {
+		close()
+	}
+
+	func populateMissingRomList() {
+		// Fill in the missing details; first build a list of all the individual
+		// line items.
+		var requestLines: [String] = []
+		for missingROM in self.missingROMs {
+			if let descriptiveName = missingROM.descriptiveName {
+				requestLines.append("• " + descriptiveName)
+			} else {
+				requestLines.append("• " + missingROM.fileName)
+			}
+		}
+
+		// Suffix everything up to the penultimate line with a semicolon;
+		// the penultimate line with a semicolon and a conjunctive; the final
+		// line with a full stop.
+		for x in 0 ..< requestLines.count {
+			if x < requestLines.count - 2 {
+				requestLines[x].append(";")
+			} else if x < requestLines.count - 1 {
+				requestLines[x].append("; and")
+			} else {
+				requestLines[x].append(".")
+			}
+		}
+		romRequesterText!.stringValue = self.romRequestBaseText + requestLines.joined(separator: "\n")
+	}
+
+	func romReceiverView(_ view: CSROMReceiverView, didReceiveFileAt URL: URL) {
+		// Test whether the file identified matches any of the currently missing ROMs.
+		// If so then remove that ROM from the missing list and update the request screen.
+		// If no ROMs are still missing, start the machine.
+		do {
+			let fileData = try Data(contentsOf: URL)
+			var didInstallRom = false
+
+			// Try to match by size first, CRC second. Accept that some ROMs may have
+			// some additional appended data. Arbitrarily allow them to be up to 10kb
+			// too large.
+			var index = 0
+			for missingROM in self.missingROMs {
+				if fileData.count >= missingROM.size && fileData.count < missingROM.size + 10*1024 {
+					// Trim to size.
+					let trimmedData = fileData[0 ..< missingROM.size]
+
+					// Get CRC.
+					if missingROM.crc32s.contains( (trimmedData as NSData).crc32 ) {
+						// This ROM matches; copy it into the application library,
+						// strike it from the missing ROM list and decide how to
+						// proceed.
+						let fileManager = FileManager.default
+						let targetPath = fileManager.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
+							.appendingPathComponent("ROMImages")
+							.appendingPathComponent(missingROM.machineName)
+						let targetFile = targetPath
+							.appendingPathComponent(missingROM.fileName)
+
+						do {
+							try fileManager.createDirectory(atPath: targetPath.path, withIntermediateDirectories: true, attributes: nil)
+							try trimmedData.write(to: targetFile)
+						} catch let error {
+							showRomReceiverError(error: "Couldn't write to application support directory: \(error)")
+						}
+
+						self.missingROMs.remove(at: index)
+						didInstallRom = true
+						break
+					}
+				}
+
+				index = index + 1
+			}
+
+			if didInstallRom {
+				if self.missingROMs.count == 0 {
+					self.windowControllers[0].window?.endSheet(self.romRequesterPanel!)
+					configureAs(self.machineDescription!)
+				} else {
+					populateMissingRomList()
+				}
+			} else {
+				showRomReceiverError(error: "Didn't recognise contents of \(URL.lastPathComponent)")
+			}
+		} catch let error {
+			showRomReceiverError(error: "Couldn't read file at \(URL.absoluteString): \(error)")
+		}
+	}
+
+	// Yucky ugliness follows; my experience as an iOS developer intersects poorly with
+	// NSAnimationContext hence the various stateful diplications below. isShowingError
+	// should be essentially a duplicate of the current alphaValue, and animationCount
+	// is to resolve my inability to figure out how to cancel scheduled animations.
+	private var errorText = ""
+	private var isShowingError = false
+	private var animationCount = 0
+	private func showRomReceiverError(error: String) {
+		// Set or append the new error.
+		if self.errorText.count > 0 {
+			self.errorText = self.errorText + "\n" + error
+		} else {
+			self.errorText = error
+		}
+
+		// Apply the new complete text.
+		romReceiverErrorField!.stringValue = self.errorText
+
+		if !isShowingError {
+			// Schedule the box's appearance.
+			NSAnimationContext.beginGrouping()
+			NSAnimationContext.current.duration = 0.1
+			romReceiverErrorField?.animator().alphaValue = 1.0
+			NSAnimationContext.endGrouping()
+			isShowingError = true
+		}
+
+		// Schedule the box to disappear.
+		self.animationCount = self.animationCount + 1
+		let capturedAnimationCount = animationCount
+		DispatchQueue.main.asyncAfter(deadline: DispatchTime.now() + .seconds(2)) {
+			if self.animationCount == capturedAnimationCount {
+				NSAnimationContext.beginGrouping()
+				NSAnimationContext.current.duration = 1.0
+				self.romReceiverErrorField?.animator().alphaValue = 0.0
+				NSAnimationContext.endGrouping()
+				self.isShowingError = false
+				self.errorText = ""
+			}
+		}
+	}
+
 	// MARK: Joystick-via-the-keyboard selection
 	@IBAction func useKeyboardAsKeyboard(_ sender: NSMenuItem?) {
 		machine.inputMode = .keyboard
@@ -301,6 +554,9 @@ class MachineDocument:
 		machine.inputMode = .joystick
 	}
 
+	/// Determines which of the menu items to enable and disable based on the ability of the
+	/// current machine to handle keyboard and joystick input, accept new media and whether
+	/// it has an associted activity window.
 	override func validateUserInterfaceItem(_ item: NSValidatedUserInterfaceItem) -> Bool {
 		if let menuItem = item as? NSMenuItem {
 			switch item.action {
@@ -334,7 +590,7 @@ class MachineDocument:
 		return super.validateUserInterfaceItem(item)
 	}
 
-	// Screenshot capture.
+	/// Saves a screenshot of the
 	@IBAction func saveScreenshot(_ sender: AnyObject!) {
 		// Grab a date formatter and form a file name.
 		let dateFormatter = DateFormatter()
@@ -358,7 +614,8 @@ class MachineDocument:
 	}
 
 	// MARK: Activity display.
-	class LED {
+
+	private class LED {
 		let levelIndicator: NSLevelIndicator
 		init(levelIndicator: NSLevelIndicator) {
 			self.levelIndicator = levelIndicator
@@ -366,11 +623,12 @@ class MachineDocument:
 		var isLit = false
 		var isBlinking = false
 	}
-	fileprivate var leds: [String: LED] = [:]
+	private var leds: [String: LED] = [:]
+
 	func setupActivityDisplay() {
 		var leds = machine.leds
 		if leds.count > 0 {
-			Bundle.main.loadNibNamed(NSNib.Name(rawValue: "Activity"), owner: self, topLevelObjects: nil)
+			Bundle.main.loadNibNamed("Activity", owner: self, topLevelObjects: nil)
 			showActivity(nil)
 
 			// Inspect the activity panel for indicators.

OSBindings/Mac/Clock Signal/High Precision Timer/CSHighPrecisionTimer.h

@@ -0,0 +1,27 @@
+//
+//  CSHighPrecisionTimer.h
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/03/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+/*!
+	Provides a high-precision timer; provide it with a block and an
+	interval, and it will ensure the block is performed as regularly
+	as the system will allow at the specified intervals.
+
+	The block will be executed on an arbitrary thread.
+*/
+@interface CSHighPrecisionTimer: NSObject
+
+/// Initialises a new instance of the high precision timer; the timer will begin
+/// ticking immediately.
+- (instancetype)initWithTask:(dispatch_block_t)task interval:(uint64_t)interval;
+
+/// Stops the timer.
+- (void)invalidate;
+
+@end

OSBindings/Mac/Clock Signal/High Precision Timer/CSHighPrecisionTimer.m

@@ -0,0 +1,37 @@
+//
+//  CSHighPrecisionTimer.m
+//  Clock Signal
+//
+//  Created by Thomas Harte on 07/03/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#import "CSHighPrecisionTimer.h"
+
+@implementation CSHighPrecisionTimer {
+	dispatch_source_t _timer;
+	dispatch_queue_t _queue;
+}
+
+- (instancetype)initWithTask:(dispatch_block_t)task interval:(uint64_t)interval {
+	self = [super init];
+	if(self) {
+		_queue = dispatch_queue_create("High precision timer queue", DISPATCH_QUEUE_SERIAL);
+		_timer = dispatch_source_create(DISPATCH_SOURCE_TYPE_TIMER, 0, 0, _queue);
+		if(_timer) {
+			dispatch_source_set_timer(_timer, dispatch_walltime(NULL, 0), interval, 0);
+			dispatch_source_set_event_handler(_timer, task);
+
+			// TODO: dispatch_activate is preferred to dispatch_resume, but arrives only
+			// as of macOS 10.12. So switch if/when upping the OS requirements.
+			dispatch_resume(_timer);
+		}
+	}
+	return self;
+}
+
+- (void)invalidate {
+	dispatch_suspend(_timer);
+}
+
+@end

OSBindings/Mac/Clock Signal/Info.plist

@@ -14,42 +14,42 @@
 			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cartridge.png</string>
+			<key>CFBundleTypeName</key>
+			<string>Atari 2600 Cartridge</string>
 			<key>CFBundleTypeOSTypes</key>
 			<array>
 				<string>????</string>
 			</array>
-			<key>CFBundleTypeName</key>
-			<string>Atari 2600 Cartridge</string>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>rom</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>chip.png</string>
 			<key>CFBundleTypeName</key>
 			<string>ROM Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
@@ -57,110 +57,110 @@
 				<string>uef</string>
 				<string>uef.gz</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Electron/BBC UEF Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>prg</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>floppy525.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Commodore Program</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>tap</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Tape Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>g64</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>floppy525.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Commodore Disk</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Editor</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>d64</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>floppy525.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Commodore 1540/1 Disk</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Editor</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
@@ -171,44 +171,44 @@
 				<string>adl</string>
 				<string>adm</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>floppy35.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Electron/BBC Disk Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Editor</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>dsk</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>floppy35.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Disk Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Editor</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
@@ -216,22 +216,22 @@
 				<string>o</string>
 				<string>80</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>ZX80 Tape Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
@@ -240,240 +240,240 @@
 				<string>81</string>
 				<string>p81</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>ZX81 Tape Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>csw</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Tape Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>tzx</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Tape Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>cdt</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Amstrad CPC Tape Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>hfe</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>floppy35.png</string>
 			<key>CFBundleTypeName</key>
 			<string>HxC Disk Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>cas</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>MSX Tape Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>dmk</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>floppy35.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Disk Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
-			<key>LSTypeIsPackage</key>
-			<false/>
 			<key>LSHandlerRank</key>
 			<string>Owner</string>
+			<key>LSTypeIsPackage</key>
+			<false/>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>tsx</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cassette.png</string>
 			<key>CFBundleTypeName</key>
 			<string>MSX Tape Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>col</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cartridge.png</string>
 			<key>CFBundleTypeName</key>
 			<string>ColecoVision Cartridge</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>sms</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cartridge.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Master System Cartridge</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
 			<array>
 				<string>sg</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>cartridge.png</string>
 			<key>CFBundleTypeName</key>
 			<string>SG1000 Cartridge</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
 		</dict>
 		<dict>
 			<key>CFBundleTypeExtensions</key>
@@ -483,22 +483,48 @@
 				<string>do</string>
 				<string>po</string>
 			</array>
-			<key>CFBundleTypeOSTypes</key>
-			<array>
-				<string>????</string>
-			</array>
 			<key>CFBundleTypeIconFile</key>
 			<string>floppy525.png</string>
 			<key>CFBundleTypeName</key>
 			<string>Apple II Disk Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
 			<key>CFBundleTypeRole</key>
 			<string>Viewer</string>
+			<key>LSHandlerRank</key>
+			<string>Owner</string>
 			<key>LSTypeIsPackage</key>
 			<false/>
 			<key>NSDocumentClass</key>
 			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
-			<key>LSHandlerRank</key>
-			<string>Owner</string>
+		</dict>
+		<dict>
+			<key>CFBundleTypeExtensions</key>
+			<array>
+				<string>img</string>
+				<string>hfv</string>
+				<string>image</string>
+			</array>
+			<key>CFBundleTypeIconFile</key>
+			<string>floppy35</string>
+			<key>CFBundleTypeMIMETypes</key>
+			<array>
+				<string>application/x-apple-diskimage</string>
+			</array>
+			<key>CFBundleTypeName</key>
+			<string>DiskCopy 4.2 Disk Image</string>
+			<key>CFBundleTypeOSTypes</key>
+			<array>
+				<string>????</string>
+			</array>
+			<key>CFBundleTypeRole</key>
+			<string>Viewer</string>
+			<key>LSTypeIsPackage</key>
+			<integer>0</integer>
+			<key>NSDocumentClass</key>
+			<string>$(PRODUCT_MODULE_NAME).MachineDocument</string>
 		</dict>
 	</array>
 	<key>CFBundleExecutable</key>
@@ -524,7 +550,7 @@
 	<key>LSMinimumSystemVersion</key>
 	<string>$(MACOSX_DEPLOYMENT_TARGET)</string>
 	<key>NSHumanReadableCopyright</key>
-	<string>Copyright 2018 Thomas Harte. All rights reserved.</string>
+	<string>Copyright 2019 Thomas Harte. All rights reserved.</string>
 	<key>NSMainNibFile</key>
 	<string>MainMenu</string>
 	<key>NSPrincipalClass</key>

OSBindings/Mac/Clock Signal/Machine/CSMachine.h

@@ -33,6 +33,14 @@ typedef NS_ENUM(NSInteger, CSMachineKeyboardInputMode) {
 	CSMachineKeyboardInputModeJoystick
 };
 
+@interface CSMissingROM: NSObject
+@property (nonatomic, readonly, nonnull) NSString *machineName;
+@property (nonatomic, readonly, nonnull) NSString *fileName;
+@property (nonatomic, readonly, nullable) NSString *descriptiveName;
+@property (nonatomic, readonly) NSUInteger size;
+@property (nonatomic, readonly, nonnull) NSArray<NSNumber *> *crc32s;
+@end
+
 // Deliberately low; to ensure CSMachine has been declared as an @class already.
 #import "CSAtari2600.h"
 #import "CSZX8081.h"
@@ -45,8 +53,10 @@ typedef NS_ENUM(NSInteger, CSMachineKeyboardInputMode) {
 	Initialises an instance of CSMachine.
 
 	@param result The CSStaticAnalyser result that describes the machine needed.
+	@param missingROMs An array that is filled with a list of ROMs that the machine requested but which
+		were not found; populated only if this `init` has failed.
 */
-- (nullable instancetype)initWithAnalyser:(nonnull CSStaticAnalyser *)result NS_DESIGNATED_INITIALIZER;
+- (nullable instancetype)initWithAnalyser:(nonnull CSStaticAnalyser *)result missingROMs:(nullable inout NSMutableArray<CSMissingROM *> *)missingROMs NS_DESIGNATED_INITIALIZER;
 
 - (void)runForInterval:(NSTimeInterval)interval;
 
@@ -61,6 +71,9 @@ typedef NS_ENUM(NSInteger, CSMachineKeyboardInputMode) {
 - (void)setKey:(uint16_t)key characters:(nullable NSString *)characters isPressed:(BOOL)isPressed;
 - (void)clearAllKeys;
 
+- (void)setMouseButton:(int)button isPressed:(BOOL)isPressed;
+- (void)addMouseMotionX:(CGFloat)deltaX y:(CGFloat)deltaY;
+
 @property (nonatomic, strong, nullable) CSAudioQueue *audioQueue;
 @property (nonatomic, readonly, nonnull) CSOpenGLView *view;
 @property (nonatomic, weak, nullable) id<CSMachineDelegate> delegate;
@@ -81,6 +94,7 @@ typedef NS_ENUM(NSInteger, CSMachineKeyboardInputMode) {
 // Input control.
 @property (nonatomic, readonly) BOOL hasExclusiveKeyboard;
 @property (nonatomic, readonly) BOOL hasJoystick;
+@property (nonatomic, readonly) BOOL hasMouse;
 @property (nonatomic, assign) CSMachineKeyboardInputMode inputMode;
 @property (nonatomic, nullable) CSJoystickManager *joystickManager;
 

OSBindings/Mac/Clock Signal/Machine/CSMachine.mm

@@ -74,6 +74,68 @@ struct ActivityObserver: public Activity::Observer {
 	__unsafe_unretained CSMachine *machine;
 };
 
+@interface CSMissingROM (Mutability)
+@property (nonatomic, nonnull, copy) NSString *machineName;
+@property (nonatomic, nonnull, copy) NSString *fileName;
+@property (nonatomic, nullable, copy) NSString *descriptiveName;
+@property (nonatomic, readwrite) NSUInteger size;
+@property (nonatomic, copy) NSArray<NSNumber *> *crc32s;
+@end
+
+@implementation CSMissingROM {
+	NSString *_machineName;
+	NSString *_fileName;
+	NSString *_descriptiveName;
+	NSUInteger _size;
+	NSArray<NSNumber *> *_crc32s;
+}
+
+- (NSString *)machineName {
+	return _machineName;
+}
+
+- (void)setMachineName:(NSString *)machineName {
+	_machineName = [machineName copy];
+}
+
+- (NSString *)fileName {
+	return _fileName;
+}
+
+- (void)setFileName:(NSString *)fileName {
+	_fileName = [fileName copy];
+}
+
+- (NSString *)descriptiveName {
+	return _descriptiveName;
+}
+
+- (void)setDescriptiveName:(NSString *)descriptiveName {
+	_descriptiveName = [descriptiveName copy];
+}
+
+- (NSUInteger)size {
+	return _size;
+}
+
+- (void)setSize:(NSUInteger)size {
+	_size = size;
+}
+
+- (NSArray<NSNumber *> *)crc32s {
+	return _crc32s;
+}
+
+- (void)setCrc32s:(NSArray<NSNumber *> *)crc32s {
+	_crc32s = [crc32s copy];
+}
+
+- (NSString *)description {
+	return [NSString stringWithFormat:@"%@/%@, %@ bytes, CRCs: %@", _fileName, _descriptiveName, @(_size), _crc32s];
+}
+
+@end
+
 @implementation CSMachine {
 	SpeakerDelegate _speakerDelegate;
 	ActivityObserver _activityObserver;
@@ -90,14 +152,37 @@ struct ActivityObserver: public Activity::Observer {
 	std::unique_ptr<Outputs::Display::OpenGL::ScanTarget> _scanTarget;
 }
 
-- (instancetype)initWithAnalyser:(CSStaticAnalyser *)result {
+- (instancetype)initWithAnalyser:(CSStaticAnalyser *)result missingROMs:(inout NSMutableArray<CSMissingROM *> *)missingROMs {
 	self = [super init];
 	if(self) {
 		_analyser = result;
 
 		Machine::Error error;
-		_machine.reset(Machine::MachineForTargets(_analyser.targets, CSROMFetcher(), error));
-		if(!_machine) return nil;
+		std::vector<ROMMachine::ROM> missing_roms;
+		_machine.reset(Machine::MachineForTargets(_analyser.targets, CSROMFetcher(&missing_roms), error));
+		if(!_machine) {
+			for(const auto &missing_rom : missing_roms) {
+				CSMissingROM *rom = [[CSMissingROM alloc] init];
+
+				// Copy/convert the primitive fields.
+				rom.machineName = [NSString stringWithUTF8String:missing_rom.machine_name.c_str()];
+				rom.fileName = [NSString stringWithUTF8String:missing_rom.file_name.c_str()];
+				rom.descriptiveName = missing_rom.descriptive_name.empty() ? nil : [NSString stringWithUTF8String:missing_rom.descriptive_name.c_str()];
+				rom.size = missing_rom.size;
+
+				// Convert the CRC list.
+				NSMutableArray<NSNumber *> *crc32s = [[NSMutableArray alloc] init];
+				for(const auto &crc : missing_rom.crc32s) {
+					[crc32s addObject:@(crc)];
+				}
+				rom.crc32s = [crc32s copy];
+
+				// Add to the missing list.
+				[missingROMs addObject:rom];
+			}
+
+			return nil;
+		}
 
 		_inputMode =
 			(_machine->keyboard_machine() && _machine->keyboard_machine()->get_keyboard().is_exclusive())
@@ -410,14 +495,14 @@ struct ActivityObserver: public Activity::Observer {
 }
 
 - (void)clearAllKeys {
-	auto keyboard_machine = _machine->keyboard_machine();
+	const auto keyboard_machine = _machine->keyboard_machine();
 	if(keyboard_machine) {
 		@synchronized(self) {
 			keyboard_machine->get_keyboard().reset_all_keys();
 		}
 	}
 
-	auto joystick_machine = _machine->joystick_machine();
+	const auto joystick_machine = _machine->joystick_machine();
 	if(joystick_machine) {
 		@synchronized(self) {
 			for(auto &joystick : joystick_machine->get_joysticks()) {
@@ -425,6 +510,31 @@ struct ActivityObserver: public Activity::Observer {
 			}
 		}
 	}
+
+	const auto mouse_machine = _machine->mouse_machine();
+	if(mouse_machine) {
+		@synchronized(self) {
+			mouse_machine->get_mouse().reset_all_buttons();
+		}
+	}
+}
+
+- (void)setMouseButton:(int)button isPressed:(BOOL)isPressed {
+	auto mouse_machine = _machine->mouse_machine();
+	if(mouse_machine) {
+		@synchronized(self) {
+			mouse_machine->get_mouse().set_button_pressed(button % mouse_machine->get_mouse().get_number_of_buttons(), isPressed);
+		}
+	}
+}
+
+- (void)addMouseMotionX:(CGFloat)deltaX y:(CGFloat)deltaY {
+	auto mouse_machine = _machine->mouse_machine();
+	if(mouse_machine) {
+		@synchronized(self) {
+			mouse_machine->get_mouse().move(int(deltaX), int(deltaY));
+		}
+	}
 }
 
 #pragma mark - Options
@@ -540,6 +650,10 @@ struct ActivityObserver: public Activity::Observer {
 	return !!_machine->joystick_machine();
 }
 
+- (BOOL)hasMouse {
+	return !!_machine->mouse_machine();
+}
+
 - (BOOL)hasExclusiveKeyboard {
 	return !!_machine->keyboard_machine() && _machine->keyboard_machine()->get_keyboard().is_exclusive();
 }

OSBindings/Mac/Clock Signal/Machine/CSROMFetcher.hpp

@@ -8,4 +8,4 @@
 
 #include "ROMMachine.hpp"
 
-ROMMachine::ROMFetcher CSROMFetcher();
+ROMMachine::ROMFetcher CSROMFetcher(std::vector<ROMMachine::ROM> *missing_roms = nullptr);

OSBindings/Mac/Clock Signal/Machine/CSROMFetcher.mm

@@ -14,15 +14,39 @@
 
 #include <string>
 
-ROMMachine::ROMFetcher CSROMFetcher() {
-	return [] (const std::string &machine, const std::vector<std::string> &names) -> std::vector<std::unique_ptr<std::vector<std::uint8_t>>> {
-		NSString *subDirectory = [@"ROMImages/" stringByAppendingString:[NSString stringWithUTF8String:machine.c_str()]];
-		std::vector<std::unique_ptr<std::vector<std::uint8_t>>> results;
-		for(const auto &name: names) {
-			NSData *fileData = [[NSBundle mainBundle] dataForResource:[NSString stringWithUTF8String:name.c_str()] withExtension:nil subdirectory:subDirectory];
+ROMMachine::ROMFetcher CSROMFetcher(std::vector<ROMMachine::ROM> *missing_roms) {
+	return [missing_roms] (const std::vector<ROMMachine::ROM> &roms) -> std::vector<std::unique_ptr<std::vector<std::uint8_t>>> {
+		NSArray<NSURL *> *const supportURLs = [[NSFileManager defaultManager] URLsForDirectory:NSApplicationSupportDirectory inDomains:NSUserDomainMask];
 
-			if(!fileData)
+		std::vector<std::unique_ptr<std::vector<std::uint8_t>>> results;
+		for(const auto &rom: roms) {
+			NSData *fileData;
+			NSString *const subdirectory = [@"ROMImages/" stringByAppendingString:[NSString stringWithUTF8String:rom.machine_name.c_str()]];
+
+			// Check for this file first within the application support directories.
+			for(NSURL *supportURL in supportURLs) {
+				NSURL *const fullURL = [[supportURL URLByAppendingPathComponent:subdirectory]
+							URLByAppendingPathComponent:[NSString stringWithUTF8String:rom.file_name.c_str()]];
+				fileData = [NSData dataWithContentsOfURL:fullURL];
+				if(fileData) break;
+			}
+
+			// Failing that, check inside the application bundle.
+			if(!fileData) {
+				fileData = [[NSBundle mainBundle]
+					dataForResource:[NSString stringWithUTF8String:rom.file_name.c_str()]
+					withExtension:nil
+					subdirectory:subdirectory];
+			}
+
+			// Store an appropriate result, accumulating a list of the missing if requested.
+			if(!fileData) {
 				results.emplace_back(nullptr);
+
+				if(missing_roms) {
+					missing_roms->push_back(rom);
+				}
+			}
 			else {
 				std::unique_ptr<std::vector<std::uint8_t>> data(new std::vector<std::uint8_t>);
 				*data = fileData.stdVector8;

OSBindings/Mac/Clock Signal/Machine/NSData+CRC32.h

@@ -0,0 +1,17 @@
+//
+//  NSData+CRC32.m
+//  Clock Signal
+//
+//  Created by Thomas Harte on 22/07/2019.
+//  Copyright 2019 Thomas Harte. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+#include <stdint.h>
+
+@interface NSData (CRC32)
+
+@property(nonnull, nonatomic, readonly) NSNumber *crc32;
+
+@end

OSBindings/Mac/Clock Signal/Machine/NSData+CRC32.m

@@ -0,0 +1,19 @@
+//
+//  NSData+CRC32.m
+//  Clock Signal
+//
+//  Created by Thomas Harte on 22/07/2019.
+//  Copyright 2019 Thomas Harte. All rights reserved.
+//
+
+#import "NSData+CRC32.h"
+
+#include <zlib.h>
+
+@implementation NSData (StdVector)
+
+- (NSNumber *)crc32 {
+    return @(crc32(crc32(0, Z_NULL, 0), self.bytes, (uInt)self.length));
+}
+
+@end

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

@@ -29,6 +29,13 @@ typedef NS_ENUM(NSInteger, CSMachineCPCModel) {
 	CSMachineCPCModel6128
 };
 
+typedef NS_ENUM(NSInteger, CSMachineMacintoshModel) {
+	CSMachineMacintoshModel128k,
+	CSMachineMacintoshModel512k,
+	CSMachineMacintoshModel512ke,
+	CSMachineMacintoshModelPlus,
+};
+
 typedef NS_ENUM(NSInteger, CSMachineOricModel) {
 	CSMachineOricModelOric1,
 	CSMachineOricModelOricAtmos,
@@ -69,6 +76,7 @@ typedef int Kilobytes;
 - (instancetype)initWithZX80MemorySize:(Kilobytes)memorySize useZX81ROM:(BOOL)useZX81ROM;
 - (instancetype)initWithZX81MemorySize:(Kilobytes)memorySize;
 - (instancetype)initWithAppleIIModel:(CSMachineAppleIIModel)model diskController:(CSMachineAppleIIDiskController)diskController;
+- (instancetype)initWithMacintoshModel:(CSMachineMacintoshModel)model;
 
 @property(nonatomic, readonly) NSString *optionsPanelNibName;
 @property(nonatomic, readonly) NSString *displayName;

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

@@ -17,6 +17,7 @@
 #include "../../../../../Analyser/Static/AmstradCPC/Target.hpp"
 #include "../../../../../Analyser/Static/AppleII/Target.hpp"
 #include "../../../../../Analyser/Static/Commodore/Target.hpp"
+#include "../../../../../Analyser/Static/Macintosh/Target.hpp"
 #include "../../../../../Analyser/Static/MSX/Target.hpp"
 #include "../../../../../Analyser/Static/Oric/Target.hpp"
 #include "../../../../../Analyser/Static/ZX8081/Target.hpp"
@@ -188,7 +189,27 @@ static Analyser::Static::ZX8081::Target::MemoryModel ZX8081MemoryModelFromSize(K
 		_targets.push_back(std::move(target));
 	}
 	return self;
+}
 
+- (instancetype)initWithMacintoshModel:(CSMachineMacintoshModel)model {
+	self = [super init];
+	if(self) {
+		using Target = Analyser::Static::Macintosh::Target;
+		std::unique_ptr<Target> target(new Target);
+		target->machine = Analyser::Machine::Macintosh;
+
+		using Model = Target::Model;
+		switch(model) {
+			default:
+			case CSMachineMacintoshModel128k:	target->model = Model::Mac128k;		break;
+			case CSMachineMacintoshModel512k:	target->model = Model::Mac512k;		break;
+			case CSMachineMacintoshModel512ke:	target->model = Model::Mac512ke;	break;
+			case CSMachineMacintoshModelPlus:	target->model = Model::MacPlus;		break;
+		}
+
+		_targets.push_back(std::move(target));
+	}
+	return self;
 }
 
 - (NSString *)optionsPanelNibName {
@@ -196,6 +217,7 @@ static Analyser::Static::ZX8081::Target::MemoryModel ZX8081MemoryModelFromSize(K
 		case Analyser::Machine::AmstradCPC:		return @"CompositeOptions";
 		case Analyser::Machine::AppleII:		return @"AppleIIOptions";
 		case Analyser::Machine::Atari2600:		return @"Atari2600Options";
+		case Analyser::Machine::ColecoVision:	return @"CompositeOptions";
 		case Analyser::Machine::Electron:		return @"QuickLoadCompositeOptions";
 		case Analyser::Machine::MasterSystem:	return @"CompositeOptions";
 		case Analyser::Machine::MSX:			return @"QuickLoadCompositeOptions";

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

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="14460.31" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="14490.70" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
     <dependencies>
         <deployment identifier="macosx"/>
-        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="14460.31"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="14490.70"/>
         <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
@@ -17,14 +17,14 @@
         <window title="Window" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" titleVisibility="hidden" id="QvC-M9-y7g">
             <windowStyleMask key="styleMask" titled="YES" documentModal="YES"/>
             <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
-            <rect key="contentRect" x="196" y="240" width="600" height="205"/>
+            <rect key="contentRect" x="196" y="240" width="650" height="205"/>
             <rect key="screenRect" x="0.0" y="0.0" width="1440" height="900"/>
             <view key="contentView" wantsLayer="YES" id="EiT-Mj-1SZ">
-                <rect key="frame" x="0.0" y="0.0" width="600" height="205"/>
+                <rect key="frame" x="0.0" y="0.0" width="650" height="205"/>
                 <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                 <subviews>
                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="hKn-1l-OSN">
-                        <rect key="frame" x="499" y="13" width="87" height="32"/>
+                        <rect key="frame" x="549" y="13" width="87" height="32"/>
                         <buttonCell key="cell" type="push" title="Choose" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="MnM-xo-4Qa">
                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                             <font key="font" metaFont="system"/>
@@ -37,7 +37,7 @@ DQ
                         </connections>
                     </button>
                     <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="JQy-Cj-AOK">
-                        <rect key="frame" x="418" y="13" width="82" height="32"/>
+                        <rect key="frame" x="468" y="13" width="82" height="32"/>
                         <buttonCell key="cell" type="push" title="Cancel" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="sub-rB-Req">
                             <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
                             <font key="font" metaFont="system"/>
@@ -59,12 +59,12 @@ Gw
                         </textFieldCell>
                     </textField>
                     <tabView translatesAutoresizingMaskIntoConstraints="NO" id="VUb-QG-x7c">
-                        <rect key="frame" x="13" y="51" width="574" height="140"/>
+                        <rect key="frame" x="13" y="51" width="624" height="140"/>
                         <font key="font" metaFont="system"/>
                         <tabViewItems>
                             <tabViewItem label="Apple II" identifier="appleii" id="P59-QG-LOa">
                                 <view key="view" id="dHz-Yv-GNq">
-                                    <rect key="frame" x="10" y="33" width="554" height="94"/>
+                                    <rect key="frame" x="10" y="33" width="604" height="94"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="V5Z-dX-Ns4">
@@ -130,7 +130,7 @@ Gw
                             </tabViewItem>
                             <tabViewItem label="Amstrad CPC" identifier="cpc" id="JmB-OF-xcM">
                                 <view key="view" id="5zS-Nj-Ynx">
-                                    <rect key="frame" x="10" y="33" width="554" height="94"/>
+                                    <rect key="frame" x="10" y="33" width="604" height="94"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="00d-sg-Krh">
@@ -168,18 +168,18 @@ Gw
                             </tabViewItem>
                             <tabViewItem label="Electron" identifier="electron" id="muc-z9-Vqc">
                                 <view key="view" id="SRc-2D-95G">
-                                    <rect key="frame" x="10" y="33" width="554" height="93"/>
+                                    <rect key="frame" x="10" y="33" width="604" height="94"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="JqM-IK-FMP">
-                                            <rect key="frame" x="15" y="74" width="164" height="18"/>
+                                            <rect key="frame" x="15" y="75" width="164" height="18"/>
                                             <buttonCell key="cell" type="check" title="With Disk Filing System" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="tpW-5C-xKp">
                                                 <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                 <font key="font" metaFont="system"/>
                                             </buttonCell>
                                         </button>
                                         <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="945-wU-JOH">
-                                            <rect key="frame" x="15" y="54" width="228" height="18"/>
+                                            <rect key="frame" x="15" y="55" width="228" height="18"/>
                                             <buttonCell key="cell" type="check" title="With Advanced Disk Filing System" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="S0c-Jg-7Pu">
                                                 <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                 <font key="font" metaFont="system"/>
@@ -197,9 +197,31 @@ Gw
                                     </constraints>
                                 </view>
                             </tabViewItem>
+                            <tabViewItem label="Macintosh" identifier="mac" id="lmR-z3-xSm">
+                                <view key="view" id="7Yf-vi-Q0W">
+                                    <rect key="frame" x="10" y="33" width="604" height="94"/>
+                                    <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                                    <subviews>
+                                        <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="F6e-UC-25u">
+                                            <rect key="frame" x="15" y="74" width="574" height="17"/>
+                                            <textFieldCell key="cell" lineBreakMode="clipping" title="At present Clock Signal emulates only the Macintosh 512ke." id="IGV-Yp-6Af">
+                                                <font key="font" usesAppearanceFont="YES"/>
+                                                <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                                                <color key="backgroundColor" name="textBackgroundColor" catalog="System" colorSpace="catalog"/>
+                                            </textFieldCell>
+                                        </textField>
+                                    </subviews>
+                                    <constraints>
+                                        <constraint firstAttribute="trailing" secondItem="F6e-UC-25u" secondAttribute="trailing" constant="17" id="42z-hS-aPq"/>
+                                        <constraint firstItem="F6e-UC-25u" firstAttribute="leading" secondItem="7Yf-vi-Q0W" secondAttribute="leading" constant="17" id="bIg-C3-xdz"/>
+                                        <constraint firstItem="F6e-UC-25u" firstAttribute="top" secondItem="7Yf-vi-Q0W" secondAttribute="top" constant="3" id="cxs-OP-oH5"/>
+                                        <constraint firstAttribute="bottom" relation="greaterThanOrEqual" secondItem="F6e-UC-25u" secondAttribute="bottom" constant="17" id="vpF-ER-pmD"/>
+                                    </constraints>
+                                </view>
+                            </tabViewItem>
                             <tabViewItem label="MSX" identifier="msx" id="6SR-DY-zdI">
                                 <view key="view" id="mWD-An-tR7">
-                                    <rect key="frame" x="10" y="33" width="554" height="94"/>
+                                    <rect key="frame" x="10" y="33" width="604" height="94"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="8xT-Pr-8SE">
@@ -233,6 +255,7 @@ Gw
                                         </textField>
                                     </subviews>
                                     <constraints>
+                                        <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="LG6-mP-SeG" secondAttribute="trailing" constant="17" id="0Oc-n7-gaM"/>
                                         <constraint firstItem="8xT-Pr-8SE" firstAttribute="top" secondItem="LG6-mP-SeG" secondAttribute="bottom" constant="6" id="LBt-4m-GDc"/>
                                         <constraint firstItem="LG6-mP-SeG" firstAttribute="top" secondItem="mWD-An-tR7" secondAttribute="top" constant="3" id="bcb-ZZ-VpQ"/>
                                         <constraint firstAttribute="trailing" relation="greaterThanOrEqual" secondItem="8xT-Pr-8SE" secondAttribute="trailing" constant="17" id="l8P-UW-8ig"/>
@@ -246,7 +269,7 @@ Gw
                             </tabViewItem>
                             <tabViewItem label="Oric" identifier="oric" id="NSx-DC-p4M">
                                 <view key="view" id="sOR-e0-8iZ">
-                                    <rect key="frame" x="10" y="33" width="554" height="94"/>
+                                    <rect key="frame" x="10" y="33" width="604" height="94"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="0ct-tf-uRH">
@@ -311,7 +334,7 @@ Gw
                             </tabViewItem>
                             <tabViewItem label="Vic-20" identifier="vic20" id="cyO-PU-hSU">
                                 <view key="view" id="fLI-XB-QCr">
-                                    <rect key="frame" x="10" y="33" width="554" height="94"/>
+                                    <rect key="frame" x="10" y="33" width="604" height="94"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ueK-gq-gaF">
@@ -388,11 +411,11 @@ Gw
                             </tabViewItem>
                             <tabViewItem label="ZX80" identifier="zx80" id="tMH-kF-GUz">
                                 <view key="view" id="8hL-Vn-Hg0">
-                                    <rect key="frame" x="10" y="33" width="554" height="93"/>
+                                    <rect key="frame" x="10" y="33" width="554" height="94"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="I1a-Eu-5UB">
-                                            <rect key="frame" x="106" y="66" width="115" height="25"/>
+                                            <rect key="frame" x="106" y="67" width="115" height="25"/>
                                             <popUpButtonCell key="cell" type="push" title="Unexpanded" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="proportionallyDown" inset="2" selectedItem="4Sa-jR-xOd" id="B8M-do-Yod">
                                                 <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                 <font key="font" metaFont="menu"/>
@@ -406,7 +429,7 @@ Gw
                                             </popUpButtonCell>
                                         </popUpButton>
                                         <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="NCX-4e-lSu">
-                                            <rect key="frame" x="15" y="71" width="87" height="17"/>
+                                            <rect key="frame" x="15" y="72" width="87" height="17"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="e6x-TE-OC5">
                                                 <font key="font" metaFont="system"/>
                                                 <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@@ -414,7 +437,7 @@ Gw
                                             </textFieldCell>
                                         </textField>
                                         <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="ReP-bV-Thu">
-                                            <rect key="frame" x="15" y="47" width="114" height="18"/>
+                                            <rect key="frame" x="15" y="48" width="114" height="18"/>
                                             <buttonCell key="cell" type="check" title="Use ZX81 ROM" bezelStyle="regularSquare" imagePosition="left" state="on" inset="2" id="VQH-nv-Pfm">
                                                 <behavior key="behavior" changeContents="YES" doesNotDimImage="YES" lightByContents="YES"/>
                                                 <font key="font" metaFont="system"/>
@@ -436,11 +459,11 @@ Gw
                             </tabViewItem>
                             <tabViewItem label="ZX81" identifier="zx81" id="Wnn-nQ-gZ6">
                                 <view key="view" id="bmd-gL-gzT">
-                                    <rect key="frame" x="10" y="33" width="554" height="93"/>
+                                    <rect key="frame" x="10" y="33" width="554" height="94"/>
                                     <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
                                     <subviews>
                                         <popUpButton verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="5aO-UX-HnX">
-                                            <rect key="frame" x="106" y="66" width="115" height="25"/>
+                                            <rect key="frame" x="106" y="67" width="115" height="25"/>
                                             <popUpButtonCell key="cell" type="push" title="Unexpanded" bezelStyle="rounded" alignment="left" lineBreakMode="truncatingTail" state="on" borderStyle="borderAndBezel" imageScaling="proportionallyDown" inset="2" selectedItem="7QC-Ij-hES" id="d3W-Gl-3Mf">
                                                 <behavior key="behavior" lightByBackground="YES" lightByGray="YES"/>
                                                 <font key="font" metaFont="menu"/>
@@ -454,7 +477,7 @@ Gw
                                             </popUpButtonCell>
                                         </popUpButton>
                                         <textField horizontalHuggingPriority="251" verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="8tU-73-XEE">
-                                            <rect key="frame" x="15" y="71" width="87" height="17"/>
+                                            <rect key="frame" x="15" y="72" width="87" height="17"/>
                                             <textFieldCell key="cell" scrollable="YES" lineBreakMode="clipping" sendsActionOnEndEditing="YES" title="Memory Size:" id="z4b-oR-Yl2">
                                                 <font key="font" metaFont="system"/>
                                                 <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
@@ -490,7 +513,7 @@ Gw
                     <constraint firstItem="VUb-QG-x7c" firstAttribute="top" secondItem="EiT-Mj-1SZ" secondAttribute="top" constant="20" id="zT3-Ea-QQJ"/>
                 </constraints>
             </view>
-            <point key="canvasLocation" x="34" y="89"/>
+            <point key="canvasLocation" x="34" y="88.5"/>
         </window>
         <customObject id="192-Eb-Rpg" customClass="MachinePicker" customModule="Clock_Signal" customModuleProvider="target">
             <connections>

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

@@ -157,6 +157,9 @@ class MachinePicker: NSObject {
 					default:	return CSStaticAnalyser(amstradCPCModel: .model6128)
 				}
 
+			case "mac":
+				return CSStaticAnalyser(macintoshModel: .model512ke)
+
 			case "msx":
 				let hasDiskDrive = msxHasDiskDriveButton!.state == .on
 				switch msxRegionButton!.selectedItem?.tag {

OSBindings/Mac/Clock Signal/ROMRequester/CSROMReceiverView.h

@@ -0,0 +1,27 @@
+//
+//  CSROMReceiverView.h
+//  Clock Signal
+//
+//  Created by Thomas Harte on 22/07/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#import <Cocoa/Cocoa.h>
+
+@class CSROMReceiverView;
+
+@protocol CSROMReciverViewDelegate
+/*!
+	Announces receipt of a file by drag and drop to the delegate.
+	@param view The view making the request.
+	@param URL The file URL of the received file.
+*/
+- (void)romReceiverView:(nonnull CSROMReceiverView *)view didReceiveFileAtURL:(nonnull NSURL *)URL;
+
+@end
+
+@interface CSROMReceiverView : NSView
+
+@property(nonatomic, weak, nullable) id <CSROMReciverViewDelegate> delegate;
+
+@end

OSBindings/Mac/Clock Signal/ROMRequester/CSROMReceiverView.m

@@ -0,0 +1,40 @@
+//
+//  CSROMReceiverView.m
+//  Clock Signal
+//
+//  Created by Thomas Harte on 22/07/2019.
+//  Copyright © 2019 Thomas Harte. All rights reserved.
+//
+
+#import "CSROMReceiverView.h"
+
+@interface CSROMReceiverView () <NSDraggingDestination>
+@end
+
+
+@implementation CSROMReceiverView
+
+- (void)awakeFromNib {
+	[super awakeFromNib];
+
+	// Accept file URLs by drag and drop.
+	[self registerForDraggedTypes:@[(__bridge NSString *)kUTTypeFileURL]];
+}
+
+#pragma mark - NSDraggingDestination
+
+- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
+	// Just forward the URLs.
+	for(NSPasteboardItem *item in [[sender draggingPasteboard] pasteboardItems]) {
+		NSURL *URL = [NSURL URLWithString:[item stringForType:(__bridge NSString *)kUTTypeFileURL]];
+		[self.delegate romReceiverView:self didReceiveFileAtURL:URL];
+	}
+	return YES;
+}
+
+- (NSDragOperation)draggingEntered:(id < NSDraggingInfo >)sender {
+	// The emulator will take a copy of any deposited ROM files.
+	return NSDragOperationCopy;
+}
+
+@end

OSBindings/Mac/Clock Signal/ROMRequester/ROMRequester.xib

@@ -0,0 +1,75 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<document type="com.apple.InterfaceBuilder3.Cocoa.XIB" version="3.0" toolsVersion="14490.70" targetRuntime="MacOSX.Cocoa" propertyAccessControl="none" useAutolayout="YES" customObjectInstantitationMethod="direct">
+    <dependencies>
+        <deployment identifier="macosx"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.CocoaPlugin" version="14490.70"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
+    </dependencies>
+    <objects>
+        <customObject id="-2" userLabel="File's Owner" customClass="MachineDocument" customModule="Clock_Signal" customModuleProvider="target">
+            <connections>
+                <outlet property="romReceiverErrorField" destination="Bia-0m-GxK" id="wnH-Kz-uXD"/>
+                <outlet property="romReceiverView" destination="EiT-Mj-1SZ" id="Y2M-Qd-i7y"/>
+                <outlet property="romRequesterPanel" destination="QvC-M9-y7g" id="saI-YH-9NP"/>
+                <outlet property="romRequesterText" destination="5qG-I3-Qav" id="J9M-T8-Xyy"/>
+            </connections>
+        </customObject>
+        <customObject id="-1" userLabel="First Responder" customClass="FirstResponder"/>
+        <customObject id="-3" userLabel="Application" customClass="NSObject"/>
+        <window title="Window" allowsToolTipsWhenApplicationIsInactive="NO" autorecalculatesKeyViewLoop="NO" releasedWhenClosed="NO" visibleAtLaunch="NO" animationBehavior="default" titleVisibility="hidden" id="QvC-M9-y7g">
+            <windowStyleMask key="styleMask" titled="YES"/>
+            <windowPositionMask key="initialPositionMask" leftStrut="YES" rightStrut="YES" topStrut="YES" bottomStrut="YES"/>
+            <rect key="contentRect" x="196" y="240" width="480" height="270"/>
+            <rect key="screenRect" x="0.0" y="0.0" width="1440" height="900"/>
+            <view key="contentView" wantsLayer="YES" id="EiT-Mj-1SZ" customClass="CSROMReceiverView">
+                <rect key="frame" x="0.0" y="0.0" width="480" height="270"/>
+                <autoresizingMask key="autoresizingMask"/>
+                <subviews>
+                    <textField verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" textCompletion="NO" translatesAutoresizingMaskIntoConstraints="NO" id="5qG-I3-Qav">
+                        <rect key="frame" x="18" y="148" width="444" height="102"/>
+                        <textFieldCell key="cell" enabled="NO" allowsUndo="NO" id="itJ-2T-0ia">
+                            <font key="font" usesAppearanceFont="YES"/>
+                            <string key="title">Clock Signal requires you to provide images of the system ROMs for this machine. They will be stored permanently; you need do this only once.

Please drag and drop the following over this view:
+
+</string>
+                            <color key="textColor" name="labelColor" catalog="System" colorSpace="catalog"/>
+                            <color key="backgroundColor" name="textBackgroundColor" catalog="System" colorSpace="catalog"/>
+                        </textFieldCell>
+                    </textField>
+                    <button verticalHuggingPriority="750" translatesAutoresizingMaskIntoConstraints="NO" id="nvl-dm-8bK">
+                        <rect key="frame" x="384" y="13" width="82" height="32"/>
+                        <buttonCell key="cell" type="push" title="Cancel" bezelStyle="rounded" alignment="center" borderStyle="border" imageScaling="proportionallyDown" inset="2" id="oS1-Pk-LsO">
+                            <behavior key="behavior" pushIn="YES" lightByBackground="YES" lightByGray="YES"/>
+                            <font key="font" metaFont="system"/>
+                            <string key="keyEquivalent" base64-UTF8="YES">
+DQ
+</string>
+                        </buttonCell>
+                        <connections>
+                            <action selector="cancelRequestROMs:" target="-2" id="58q-yi-dlv"/>
+                        </connections>
+                    </button>
+                    <textField verticalHuggingPriority="750" horizontalCompressionResistancePriority="250" textCompletion="NO" translatesAutoresizingMaskIntoConstraints="NO" id="Bia-0m-GxK">
+                        <rect key="frame" x="20" y="61" width="442" height="17"/>
+                        <textFieldCell key="cell" allowsUndo="NO" alignment="center" title="Multiline Label" drawsBackground="YES" id="8jl-xs-LjP">
+                            <font key="font" metaFont="message"/>
+                            <color key="textColor" name="textBackgroundColor" catalog="System" colorSpace="catalog"/>
+                            <color key="backgroundColor" name="tertiaryLabelColor" catalog="System" colorSpace="catalog"/>
+                        </textFieldCell>
+                    </textField>
+                </subviews>
+                <constraints>
+                    <constraint firstItem="Bia-0m-GxK" firstAttribute="leading" secondItem="EiT-Mj-1SZ" secondAttribute="leading" constant="20" id="9Lj-3p-7Vr"/>
+                    <constraint firstAttribute="trailing" secondItem="5qG-I3-Qav" secondAttribute="trailing" constant="20" id="AwT-WO-Nyf"/>
+                    <constraint firstAttribute="bottom" secondItem="nvl-dm-8bK" secondAttribute="bottom" constant="20" id="BU0-5T-YRH"/>
+                    <constraint firstAttribute="bottom" secondItem="Bia-0m-GxK" secondAttribute="bottom" constant="61" id="ENn-7a-NGa"/>
+                    <constraint firstAttribute="trailing" secondItem="Bia-0m-GxK" secondAttribute="trailing" constant="18" id="UUy-bf-87w"/>
+                    <constraint firstItem="5qG-I3-Qav" firstAttribute="leading" secondItem="EiT-Mj-1SZ" secondAttribute="leading" constant="20" id="bRM-z1-cRf"/>
+                    <constraint firstAttribute="trailing" secondItem="nvl-dm-8bK" secondAttribute="trailing" constant="20" id="eQI-Nj-ane"/>
+                    <constraint firstItem="nvl-dm-8bK" firstAttribute="top" relation="greaterThanOrEqual" secondItem="5qG-I3-Qav" secondAttribute="bottom" constant="17" id="plB-x4-He5"/>
+                    <constraint firstItem="5qG-I3-Qav" firstAttribute="top" secondItem="EiT-Mj-1SZ" secondAttribute="top" constant="20" id="qeC-Rh-hmr"/>
+                </constraints>
+            </view>
+        </window>
+    </objects>
+</document>

OSBindings/Mac/Clock Signal/Views/CSOpenGLView.h

@@ -63,6 +63,29 @@ typedef NS_ENUM(NSInteger, CSOpenGLViewRedrawEvent) {
 */
 - (void)paste:(nonnull id)sender;
 
+@optional
+
+/*!
+	Supplies a mouse moved event to the delegate. This functions only if
+	shouldCaptureMouse is set to YES, in which case the view will ensure it captures
+	the mouse and returns only relative motion
+	(Cf. CGAssociateMouseAndMouseCursorPosition). It will also elide mouseDragged:
+	(and rightMouseDragged:, etc) and mouseMoved: events.
+*/
+- (void)mouseMoved:(nonnull NSEvent *)event;
+
+/*!
+	Supplies a mouse button down event. This elides mouseDown, rightMouseDown and otherMouseDown.
+	@c shouldCaptureMouse must be set to @c YES to receive these events.
+*/
+- (void)mouseDown:(nonnull NSEvent *)event;
+
+/*!
+	Supplies a mouse button up event. This elides mouseUp, rightMouseUp and otherMouseUp.
+	@c shouldCaptureMouse must be set to @c YES to receive these events.
+*/
+- (void)mouseUp:(nonnull NSEvent *)event;
+
 @end
 
 /*!
@@ -74,6 +97,8 @@ typedef NS_ENUM(NSInteger, CSOpenGLViewRedrawEvent) {
 @property (atomic, weak, nullable) id <CSOpenGLViewDelegate> delegate;
 @property (nonatomic, weak, nullable) id <CSOpenGLViewResponderDelegate> responderDelegate;
 
+@property (nonatomic, assign) BOOL shouldCaptureMouse;
+
 /*!
 	Ends the timer tracking time; should be called prior to giving up the last owning reference
 	to ensure that any retain cycles implied by the timer are resolved.
@@ -89,4 +114,9 @@ typedef NS_ENUM(NSInteger, CSOpenGLViewRedrawEvent) {
 */
 - (void)performWithGLContext:(nonnull dispatch_block_t)action;
 
+/*!
+	Instructs that the mouse cursor, if currently captured, should be released.
+*/
+- (void)releaseMouse;
+
 @end

OSBindings/Mac/Clock Signal/Views/CSOpenGLView.m

@@ -16,10 +16,15 @@
 @implementation CSOpenGLView {
 	CVDisplayLinkRef _displayLink;
 	CGSize _backingSize;
+
+	NSTrackingArea *_mouseTrackingArea;
+	NSTimer *_mouseHideTimer;
+	BOOL _mouseIsCaptured;
 }
 
-- (void)prepareOpenGL
-{
+- (void)prepareOpenGL {
+	[super prepareOpenGL];
+
 	// Synchronize buffer swaps with vertical refresh rate
 	GLint swapInt = 1;
 	[[self openGLContext] setValues:&swapInt forParameter:NSOpenGLCPSwapInterval];
@@ -43,47 +48,43 @@
 	CVDisplayLinkStart(_displayLink);
 }
 
-static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp *now, const CVTimeStamp *outputTime, CVOptionFlags flagsIn, CVOptionFlags *flagsOut, void *displayLinkContext)
-{
+static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeStamp *now, const CVTimeStamp *outputTime, CVOptionFlags flagsIn, CVOptionFlags *flagsOut, void *displayLinkContext) {
 	CSOpenGLView *const view = (__bridge CSOpenGLView *)displayLinkContext;
 	[view drawAtTime:now frequency:CVDisplayLinkGetActualOutputVideoRefreshPeriod(displayLink)];
 	return kCVReturnSuccess;
 }
 
-- (void)drawAtTime:(const CVTimeStamp *)now frequency:(double)frequency
-{
-	// Draw the display now regardless of other activity.
+- (void)drawAtTime:(const CVTimeStamp *)now frequency:(double)frequency {
+	[self redrawWithEvent:CSOpenGLViewRedrawEventTimer];
+}
+
+- (void)drawRect:(NSRect)dirtyRect {
+	[self redrawWithEvent:CSOpenGLViewRedrawEventAppKit];
+}
+
+- (void)redrawWithEvent:(CSOpenGLViewRedrawEvent)event {
 	[self performWithGLContext:^{
-		[self.delegate openGLViewRedraw:self event:CSOpenGLViewRedrawEventTimer];
+		[self.delegate openGLViewRedraw:self event:event];
 		CGLFlushDrawable([[self openGLContext] CGLContextObj]);
 	}];
 }
 
-- (void)drawRect:(NSRect)dirtyRect
-{
-	[self.delegate openGLViewRedraw:self event:CSOpenGLViewRedrawEventAppKit];
-}
-
-- (void)invalidate
-{
+- (void)invalidate {
 	CVDisplayLinkStop(_displayLink);
 }
 
-- (void)dealloc
-{
+- (void)dealloc {
 	// Release the display link
 	CVDisplayLinkRelease(_displayLink);
 }
 
-- (CGSize)backingSize
-{
+- (CGSize)backingSize {
 	@synchronized(self) {
 		return _backingSize;
 	}
 }
 
-- (void)reshape
-{
+- (void)reshape {
 	[super reshape];
 	@synchronized(self) {
 		_backingSize = [self convertSizeToBacking:self.bounds.size];
@@ -95,10 +96,8 @@ static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeSt
 	}];
 }
 
-- (void)awakeFromNib
-{
-	NSOpenGLPixelFormatAttribute attributes[] =
-	{
+- (void)awakeFromNib {
+	NSOpenGLPixelFormatAttribute attributes[] = {
 		NSOpenGLPFADoubleBuffer,
 		NSOpenGLPFAOpenGLProfile,	NSOpenGLProfileVersion3_2Core,
 //		NSOpenGLPFAMultisample,
@@ -127,8 +126,7 @@ static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeSt
 	[self registerForDraggedTypes:@[(__bridge NSString *)kUTTypeFileURL]];
 }
 
-- (void)performWithGLContext:(dispatch_block_t)action
-{
+- (void)performWithGLContext:(dispatch_block_t)action {
 	CGLLockContext([[self openGLContext] CGLContextObj]);
 	[self.openGLContext makeCurrentContext];
 	action();
@@ -137,47 +135,196 @@ static CVReturn DisplayLinkCallback(CVDisplayLinkRef displayLink, const CVTimeSt
 
 #pragma mark - NSResponder
 
-- (BOOL)acceptsFirstResponder
-{
+- (BOOL)acceptsFirstResponder {
 	return YES;
 }
 
-- (void)keyDown:(NSEvent *)theEvent
-{
+- (void)keyDown:(NSEvent *)theEvent {
 	[self.responderDelegate keyDown:theEvent];
 }
 
-- (void)keyUp:(NSEvent *)theEvent
-{
+- (void)keyUp:(NSEvent *)theEvent {
 	[self.responderDelegate keyUp:theEvent];
 }
 
-- (void)flagsChanged:(NSEvent *)theEvent
-{
+- (void)flagsChanged:(NSEvent *)theEvent {
 	[self.responderDelegate flagsChanged:theEvent];
+
+	// Release the mouse upon a control + command.
+	if(_mouseIsCaptured &&
+		theEvent.modifierFlags & NSEventModifierFlagControl &&
+		theEvent.modifierFlags & NSEventModifierFlagCommand) {
+		[self releaseMouse];
+	}
 }
 
-- (void)paste:(id)sender
-{
+- (void)paste:(id)sender {
 	[self.responderDelegate paste:sender];
 }
 
 #pragma mark - NSDraggingDestination
 
-- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender
-{
-	for(NSPasteboardItem *item in [[sender draggingPasteboard] pasteboardItems])
-	{
+- (BOOL)performDragOperation:(id <NSDraggingInfo>)sender {
+	for(NSPasteboardItem *item in [[sender draggingPasteboard] pasteboardItems]) {
 		NSURL *URL = [NSURL URLWithString:[item stringForType:(__bridge NSString *)kUTTypeFileURL]];
 		[self.delegate openGLView:self didReceiveFileAtURL:URL];
 	}
 	return YES;
 }
 
-- (NSDragOperation)draggingEntered:(id < NSDraggingInfo >)sender
-{
-	// we'll drag and drop, yeah?
+- (NSDragOperation)draggingEntered:(id < NSDraggingInfo >)sender {
 	return NSDragOperationLink;
 }
 
+#pragma mark - Mouse hiding
+
+- (void)setShouldCaptureMouse:(BOOL)shouldCaptureMouse {
+	_shouldCaptureMouse = shouldCaptureMouse;
+}
+
+- (void)updateTrackingAreas {
+	[super updateTrackingAreas];
+
+	if(_mouseTrackingArea) {
+		[self removeTrackingArea:_mouseTrackingArea];
+	}
+	_mouseTrackingArea =
+		[[NSTrackingArea alloc]
+			initWithRect:self.bounds
+			options:NSTrackingMouseEnteredAndExited | NSTrackingMouseMoved | NSTrackingActiveWhenFirstResponder
+			owner:self
+			userInfo:nil];
+	[self addTrackingArea:_mouseTrackingArea];
+}
+
+- (void)scheduleMouseHide {
+	if(!self.shouldCaptureMouse) {
+		[_mouseHideTimer invalidate];
+
+		_mouseHideTimer = [NSTimer scheduledTimerWithTimeInterval:3.0 repeats:NO block:^(NSTimer * _Nonnull timer) {
+			[NSCursor setHiddenUntilMouseMoves:YES];
+		}];
+	}
+}
+
+- (void)mouseEntered:(NSEvent *)event {
+	[super mouseEntered:event];
+	[self scheduleMouseHide];
+}
+
+- (void)mouseExited:(NSEvent *)event {
+	[super mouseExited:event];
+	[_mouseHideTimer invalidate];
+	_mouseHideTimer = nil;
+}
+
+- (void)releaseMouse {
+	if(_mouseIsCaptured) {
+		_mouseIsCaptured = NO;
+		CGAssociateMouseAndMouseCursorPosition(true);
+		[NSCursor unhide];
+	}
+}
+
+#pragma mark - Mouse motion
+
+- (void)applyMouseMotion:(NSEvent *)event {
+	if(!self.shouldCaptureMouse) {
+		// Mouse capture is off, so don't play games with the cursor, just schedule it to
+		// hide in the near future.
+		[self scheduleMouseHide];
+	} else {
+		if(_mouseIsCaptured) {
+			// Mouse capture is on, so move the cursor back to the middle of the window, and
+			// forward the deltas to the listener.
+			//
+			// TODO: should I really need to invert the y coordinate myself? It suggests I
+			// might have an error in mapping here.
+			const NSPoint windowCentre = [self convertPoint:CGPointMake(self.bounds.size.width * 0.5, self.bounds.size.height * 0.5) toView:nil];
+			const NSPoint screenCentre = [self.window convertPointToScreen:windowCentre];
+			const CGRect screenFrame = self.window.screen.frame;
+			CGWarpMouseCursorPosition(NSMakePoint(
+				screenFrame.origin.x + screenCentre.x,
+				screenFrame.origin.y + screenFrame.size.height - screenCentre.y
+			));
+
+			[self.responderDelegate mouseMoved:event];
+		}
+	}
+}
+
+- (void)mouseDragged:(NSEvent *)event {
+	[self applyMouseMotion:event];
+	[super mouseDragged:event];
+}
+
+- (void)rightMouseDragged:(NSEvent *)event {
+	[self applyMouseMotion:event];
+	[super rightMouseDragged:event];
+}
+
+- (void)otherMouseDragged:(NSEvent *)event {
+	[self applyMouseMotion:event];
+	[super otherMouseDragged:event];
+}
+
+- (void)mouseMoved:(NSEvent *)event {
+	[self applyMouseMotion:event];
+	[super mouseMoved:event];
+}
+
+#pragma mark - Mouse buttons
+
+- (void)applyButtonDown:(NSEvent *)event {
+	if(self.shouldCaptureMouse) {
+		if(!_mouseIsCaptured) {
+			_mouseIsCaptured = YES;
+			[NSCursor hide];
+			CGAssociateMouseAndMouseCursorPosition(false);
+
+			// Don't report the first click to the delegate; treat that as merely
+			// an invitation to capture the cursor.
+			return;
+		}
+
+		[self.responderDelegate mouseDown:event];
+	}
+}
+
+- (void)applyButtonUp:(NSEvent *)event {
+	if(self.shouldCaptureMouse) {
+		[self.responderDelegate mouseUp:event];
+	}
+}
+
+- (void)mouseDown:(NSEvent *)event {
+	[self applyButtonDown:event];
+	[super mouseDown:event];
+}
+
+- (void)rightMouseDown:(NSEvent *)event {
+	[self applyButtonDown:event];
+	[super rightMouseDown:event];
+}
+
+- (void)otherMouseDown:(NSEvent *)event {
+	[self applyButtonDown:event];
+	[super otherMouseDown:event];
+}
+
+- (void)mouseUp:(NSEvent *)event {
+	[self applyButtonUp:event];
+	[super mouseUp:event];
+}
+
+- (void)rightMouseUp:(NSEvent *)event  {
+	[self applyButtonUp:event];
+	[super rightMouseUp:event];
+}
+
+- (void)otherMouseUp:(NSEvent *)event {
+	[self applyButtonUp:event];
+	[super otherMouseUp:event];
+}
+
 @end

OSBindings/Mac/Clock SignalTests/6522Tests.swift

@@ -11,118 +11,244 @@ import Foundation
 
 class MOS6522Tests: XCTestCase {
 
-	fileprivate func with6522(_ action: (MOS6522Bridge) -> ()) {
-		let bridge = MOS6522Bridge()
-		action(bridge)
+	private var m6522: MOS6522Bridge!
+
+	override func setUp() {
+		m6522 = MOS6522Bridge()
 	}
 
 	// MARK: Timer tests
 
 	func testTimerCount() {
-		with6522 {
-			// set timer 1 to a value of $000a
-			$0.setValue(10, forRegister: 4)
-			$0.setValue(0, forRegister: 5)
+		// set timer 1 to a value of m652200a
+		m6522.setValue(10, forRegister: 4)
+		m6522.setValue(0, forRegister: 5)
 
-			// complete the setting cycle
-			$0.run(forHalfCycles: 2)
+		// complete the setting cycle
+		m6522.run(forHalfCycles: 2)
 
-			// run for 5 cycles
-			$0.run(forHalfCycles: 10)
+		// run for 5 cycles
+		m6522.run(forHalfCycles: 10)
 
-			// check that the timer has gone down by 5
-			XCTAssert($0.value(forRegister: 4) == 5, "Low order byte should be 5; was \($0.value(forRegister: 4))")
-			XCTAssert($0.value(forRegister: 5) == 0, "High order byte should be 0; was \($0.value(forRegister: 5))")
-		}
+		// check that the timer has gone down by 5
+		XCTAssert(m6522.value(forRegister: 4) == 5, "Low order byte should be 5; was \(m6522.value(forRegister: 4))")
+		XCTAssert(m6522.value(forRegister: 5) == 0, "High order byte should be 0; was \(m6522.value(forRegister: 5))")
 	}
 
 	func testTimerLatches() {
-		with6522 {
-			// set timer 2 to $1020
-			$0.setValue(0x10, forRegister: 8)
-			$0.setValue(0x20, forRegister: 9)
+		// set timer 2 to $1020
+		m6522.setValue(0x10, forRegister: 8)
+		m6522.setValue(0x20, forRegister: 9)
 
-			// change the low-byte latch
-			$0.setValue(0x40, forRegister: 8)
+		// change the low-byte latch
+		m6522.setValue(0x40, forRegister: 8)
 
-			// complete the cycle
-			$0.run(forHalfCycles: 2)
+		// complete the cycle
+		m6522.run(forHalfCycles: 2)
 
-			// chek that the new latched value hasn't been copied
-			XCTAssert($0.value(forRegister: 8) == 0x10, "Low order byte should be 0x10; was \($0.value(forRegister: 8))")
-			XCTAssert($0.value(forRegister: 9) == 0x20, "High order byte should be 0x20; was \($0.value(forRegister: 9))")
+		// chek that the new latched value hasn't been copied
+		XCTAssert(m6522.value(forRegister: 8) == 0x10, "Low order byte should be 0x10; was \(m6522.value(forRegister: 8))")
+		XCTAssert(m6522.value(forRegister: 9) == 0x20, "High order byte should be 0x20; was \(m6522.value(forRegister: 9))")
 
-			// write the low-byte latch
-			$0.setValue(0x50, forRegister: 9)
+		// write the low-byte latch
+		m6522.setValue(0x50, forRegister: 9)
 
-			// complete the cycle
-			$0.run(forHalfCycles: 2)
+		// complete the cycle
+		m6522.run(forHalfCycles: 2)
 
-			// chek that the latched value has been copied
-			XCTAssert($0.value(forRegister: 8) == 0x40, "Low order byte should be 0x50; was \($0.value(forRegister: 8))")
-			XCTAssert($0.value(forRegister: 9) == 0x50, "High order byte should be 0x40; was \($0.value(forRegister: 9))")
-		}
+		// chek that the latched value has been copied
+		XCTAssert(m6522.value(forRegister: 8) == 0x40, "Low order byte should be 0x50; was \(m6522.value(forRegister: 8))")
+		XCTAssert(m6522.value(forRegister: 9) == 0x50, "High order byte should be 0x40; was \(m6522.value(forRegister: 9))")
 	}
 
 	func testTimerReload() {
-		with6522 {
-			// set timer 1 to a value of $0010, enable repeating mode
-			$0.setValue(16, forRegister: 4)
-			$0.setValue(0, forRegister: 5)
-			$0.setValue(0x40, forRegister: 11)
-			$0.setValue(0x40 | 0x80, forRegister: 14)
+		// set timer 1 to a value of m6522010, enable repeating mode
+		m6522.setValue(16, forRegister: 4)
+		m6522.setValue(0, forRegister: 5)
+		m6522.setValue(0x40, forRegister: 11)
+		m6522.setValue(0x40 | 0x80, forRegister: 14)
 
-			// complete the cycle to set initial values
-			$0.run(forHalfCycles: 2)
+		// complete the cycle to set initial values
+		m6522.run(forHalfCycles: 2)
 
-			// run for 16 cycles
-			$0.run(forHalfCycles: 32)
+		// run for 16 cycles
+		m6522.run(forHalfCycles: 32)
 
-			// check that the timer has gone down to 0 but not yet triggered an interrupt
-			XCTAssert($0.value(forRegister: 4) == 0, "Low order byte should be 0; was \($0.value(forRegister: 4))")
-			XCTAssert($0.value(forRegister: 5) == 0, "High order byte should be 0; was \($0.value(forRegister: 5))")
-			XCTAssert(!$0.irqLine, "IRQ should not yet be active")
+		// check that the timer has gone down to 0 but not yet triggered an interrupt
+		XCTAssert(m6522.value(forRegister: 4) == 0, "Low order byte should be 0; was \(m6522.value(forRegister: 4))")
+		XCTAssert(m6522.value(forRegister: 5) == 0, "High order byte should be 0; was \(m6522.value(forRegister: 5))")
+		XCTAssert(!m6522.irqLine, "IRQ should not yet be active")
 
-			// check that two half-cycles later the timer is $ffff but IRQ still hasn't triggered
-			$0.run(forHalfCycles: 2)
-			XCTAssert($0.value(forRegister: 4) == 0xff, "Low order byte should be 0xff; was \($0.value(forRegister: 4))")
-			XCTAssert($0.value(forRegister: 5) == 0xff, "High order byte should be 0xff; was \($0.value(forRegister: 5))")
-			XCTAssert(!$0.irqLine, "IRQ should not yet be active")
+		// check that two half-cycles later the timer is $ffff but IRQ still hasn't triggered
+		m6522.run(forHalfCycles: 2)
+		XCTAssert(m6522.value(forRegister: 4) == 0xff, "Low order byte should be 0xff; was \(m6522.value(forRegister: 4))")
+		XCTAssert(m6522.value(forRegister: 5) == 0xff, "High order byte should be 0xff; was \(m6522.value(forRegister: 5))")
+		XCTAssert(!m6522.irqLine, "IRQ should not yet be active")
 
-			// check that one half-cycle later the timer is still $ffff and IRQ has triggered...
-			$0.run(forHalfCycles: 1)
-			XCTAssert($0.irqLine, "IRQ should be active")
-			XCTAssert($0.value(forRegister: 4) == 0xff, "Low order byte should be 0xff; was \($0.value(forRegister: 4))")
-			XCTAssert($0.value(forRegister: 5) == 0xff, "High order byte should be 0xff; was \($0.value(forRegister: 5))")
+		// check that one half-cycle later the timer is still $ffff and IRQ has triggered...
+		m6522.run(forHalfCycles: 1)
+		XCTAssert(m6522.irqLine, "IRQ should be active")
+		XCTAssert(m6522.value(forRegister: 4) == 0xff, "Low order byte should be 0xff; was \(m6522.value(forRegister: 4))")
+		XCTAssert(m6522.value(forRegister: 5) == 0xff, "High order byte should be 0xff; was \(m6522.value(forRegister: 5))")
 
-			// ... but that reading the timer cleared the interrupt
-			XCTAssert(!$0.irqLine, "IRQ should be active")
+		// ... but that reading the timer cleared the interrupt
+		XCTAssert(!m6522.irqLine, "IRQ should be active")
 
-			// check that one half-cycles later the timer has reloaded
-			$0.run(forHalfCycles: 1)
-			XCTAssert($0.value(forRegister: 4) == 0x10, "Low order byte should be 0x10; was \($0.value(forRegister: 4))")
-			XCTAssert($0.value(forRegister: 5) == 0x00, "High order byte should be 0x00; was \($0.value(forRegister: 5))")
-		}
+		// check that one half-cycles later the timer has reloaded
+		m6522.run(forHalfCycles: 1)
+		XCTAssert(m6522.value(forRegister: 4) == 0x10, "Low order byte should be 0x10; was \(m6522.value(forRegister: 4))")
+		XCTAssert(m6522.value(forRegister: 5) == 0x00, "High order byte should be 0x00; was \(m6522.value(forRegister: 5))")
 	}
 
 
 	// MARK: Data direction tests
 	func testDataDirection() {
-		with6522 {
-			// set low four bits of register B as output, the top four as input
-			$0.setValue(0xf0, forRegister: 2)
+		// set low four bits of register B as output, the top four as input
+		m6522.setValue(0xf0, forRegister: 2)
 
-			// ask to output 0x8c
-			$0.setValue(0x8c, forRegister: 0)
+		// ask to output 0x8c
+		m6522.setValue(0x8c, forRegister: 0)
 
-			// complete the cycle
-			$0.run(forHalfCycles: 2)
+		// complete the cycle
+		m6522.run(forHalfCycles: 2)
 
-			// set current input as 0xda
-			$0.portBInput = 0xda
+		// set current input as 0xda
+		m6522.portBInput = 0xda
 
-			// test that the result of reading register B is therefore 0x8a
-			XCTAssert($0.value(forRegister: 0) == 0x8a, "Data direction register should mix input and output; got \($0.value(forRegister: 0))")
+		// test that the result of reading register B is therefore 0x8a
+		XCTAssert(m6522.value(forRegister: 0) == 0x8a, "Data direction register should mix input and output; got \(m6522.value(forRegister: 0))")
+	}
+
+	func testShiftDisabled() {
+		/*
+			Mode 0 disables the Shift Register. In this mode the microprocessor can
+			write or read the SR and the SR will shift on each CB1 positive edge
+			shifting in the value on CB2. In this mode the SR Interrupt Flag is
+			disabled (held to a logic 0).
+		*/
+	}
+
+	func testShiftInUnderT2() {
+		/*
+			In mode 1, the shifting rate is controlled by the low order 8 bits of T2
+			(Figure 22). Shift pulses are generated on the CB1 pin to control shifting
+			in external devices. The time between transitions of this output clock is a
+			function of the system clock period and the contents of the low order T2
+			latch (N).
+
+			The shifting operation is triggered by the read or write of the SR if the
+			SR flag is set in the IFR. Otherwise the first shift will occur at the next
+			time-out of T2 after a read or write of the SR. Data is shifted first into
+			the low order bit of SR and is then shifted into the next higher order bit
+			of the shift register on the negative-going edge of each clock pulse. The
+			input data should change before the positive-going edge of the CB1 clock
+			pulse. This data is shifted into shift register during the 02 clock cycle
+			following the positive-going edge of the CB1 clock pulse. After 8 CB1 clock
+			pulses, the shift register interrupt flag will set and IRQ will go low.
+		*/
+	}
+
+	func testShiftInUnderPhase2() {
+		/*
+			In mode 2, the shift rate is a direct function of the system clock
+			frequency (Figure 23). CB1 becomes an output which generates shift pulses
+			for controlling external devices. Timer 2 operates as an independent
+			interval timer and has no effect on SR. The shifting operation is triggered
+			by reading or writing the Shift Register. Data is shifted, first into bit 0
+			and is then shifted into the next higher order bit of the shift register on
+			the trailing edge of each 02 clock pulse. After 8 clock pulses, the shift
+			register interrupt flag will be set, and the output clock pulses on CB1
+			will stop.
+		*/
+	}
+
+	func testShiftInUnderCB1() {
+		/*
+			In mode 3, external pin CB1 becomes an input (Figure 24). This allows an
+			external device to load the shift register at its own pace. The shift
+			register counter will interrupt the processor each time 8 bits have been
+			shifted in. However the shift register counter does not stop the shifting
+			operation; it acts simply as a pulse counter. Reading or writing the Shift
+			Register resets the Interrupt Flag and initializes the SR counter to count
+			another 8 pulses.
+
+			Note that the data is shifted during the first system clock cycle
+			following the positive-going edge of the CB1 shift pulse. For this reason,
+			data must be held stable during the first full cycle following CB1 going
+			high.
+		*/
+	}
+
+	func testShiftOutUnderT2FreeRunning() {
+		/*
+			Mode 4 is very similar to mode 5 in which the shifting rate is set by T2.
+			However, in mode 4 the SR Counter does not stop the shifting operation
+			(Figure 25). Since the Shift Register bit 7 (SR7) is recirculated back into
+			bit 0, the 8 bits loaded into the Shift Register will be clocked onto CB2
+			repetitively. In this mode the Shift Register Counter is disabled.
+		*/
+	}
+
+	func testShiftOutUnderT2() {
+		/*
+			In mode 5, the shift rate is controlled by T2 (as in mode 4). The shifting
+			operation is triggered by the read or write of the SR if the SR flag is set
+			in the IFR (Figure 26). Otherwise the first shift will occur at the next
+			time-out of T2 after a read or write of the SR. However, with each read or
+			write of the shift register the SR Counter is reset and 8 bits are shifted
+			onto CB2. At the same time, 8 shift pulses are generated on CB1 to control
+			shifting in external devices. After the 8 shift pulses, the shifting is
+			disabled, the SR Interrupt Flag is set and CB2 remains at the last data
+			level.
+		*/
+	}
+
+	func testShiftOutUnderPhase2() {
+		/*
+			In mode 6, the shift rate is controlled by the 02 system clock (Figure 27).
+
+			(... and I'm assuming the same behaviour as shift out under control of T2
+			otherwise, based on original context)
+		*/
+		// Set the shift register to a non-zero something.
+		m6522.setValue(0xaa, forRegister: 10)
+
+		// Set shift register mode 6.
+		m6522.setValue(6 << 2, forRegister: 11)
+
+		// Make sure the shift register's interrupt bit is set.
+		m6522.run(forHalfCycles: 16)
+		XCTAssertEqual(m6522.value(forRegister: 13) & 0x04, 0x04)
+
+		// Test that output is now inhibited: CB2 should remain unchanged.
+		let initialOutput = m6522.value(forControlLine: .two, port: .B)
+		for _ in 1...8 {
+			m6522.run(forHalfCycles: 2)
+			XCTAssertEqual(m6522.value(forControlLine: .two, port: .B), initialOutput)
 		}
+
+		// Set a new value to the shift register.
+		m6522.setValue(0x16, forRegister: 10)
+
+		// Test that the new value is shifted out.
+		var output = 0
+		for _ in 1..<8 {
+			m6522.run(forHalfCycles: 2)
+			output = (output << 1) | (m6522.value(forControlLine: .two, port: .B) ? 1 : 0)
+		}
+		XCTAssertEqual(output, 0x16)
+	}
+
+	func testShiftOutUnderCB1() {
+		/*
+			In mode 7, shifting is controlled by pulses applied to the CB1 pin by an
+			external device (Figure 28). The SR counter sets the SR Interrupt Flag each
+			time it counts 8 pulses but it does not disable the shifting function. Each
+			time the microprocessor, writes or reads the shift register, the SR
+			Interrupt Flag is reset and the SR counter is initialized to begin counting
+			the next 8 shift pulses on pin CB1. After 8 shift pulses, the Interrupt
+			Flag is set. The microprocessor can then load the shift register with the
+			next byte of data.
+		*/
 	}
 }

OSBindings/Mac/Clock SignalTests/68000 Coverage/readme.txt

@@ -0,0 +1,5 @@
+This file provides a record of which opcodes are valid and which are invalid on a
+real 68000. It was generated by AtariZoll and made available via
+http://www.atari-forum.com/viewtopic.php?f=68&t=26820 .
+
+No licence was specified.

OSBindings/Mac/Clock SignalTests/68000BCDTests.mm

@@ -0,0 +1,291 @@
+//
+//  68000BCDTests.m
+//  Clock SignalTests
+//
+//  Created by Thomas Harte on 29/06/2019.
+//
+//  Largely ported from the tests of the Portable 68k Emulator.
+//
+
+#import <XCTest/XCTest.h>
+
+#include "TestRunner68000.hpp"
+
+@interface M68000BCDTests : XCTestCase
+@end
+
+@implementation M68000BCDTests {
+	std::unique_ptr<RAM68000> _machine;
+}
+
+- (void)setUp {
+    _machine.reset(new RAM68000());
+}
+
+- (void)tearDown {
+	_machine.reset();
+}
+
+// MARK: ABCD
+
+- (void)testABCD {
+	_machine->set_program({
+		0xc302,		// ABCD D2, D1
+	});
+	auto state = _machine->get_processor_state();
+	state.data[1] = 0x1234567a;
+	state.data[2] = 0xf745ff78;
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssert(state.status & Flag::Carry);
+	XCTAssertEqual(state.data[1], 0x12345658);
+	XCTAssertEqual(state.data[2], 0xf745ff78);
+}
+
+- (void)testABCDZero {
+	_machine->set_program({
+		0xc302,		// ABCD D2, D1
+	});
+	auto state = _machine->get_processor_state();
+	state.data[1] = 0x12345600;
+	state.data[2] = 0x12345600;
+	state.status = Flag::Zero;
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssert(state.status & Flag::Zero);
+	XCTAssertEqual(state.data[1], 0x12345600);
+	XCTAssertEqual(state.data[2], 0x12345600);
+}
+
+- (void)testABCDNegative {
+	_machine->set_program({
+		0xc302,		// ABCD D2, D1
+	});
+	auto state = _machine->get_processor_state();
+	state.data[1] = 0x12345645;
+	state.data[2] = 0x12345654;
+	state.status = Flag::Zero;
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssert(state.status & Flag::Negative);
+	XCTAssertEqual(state.data[1], 0x12345699);
+	XCTAssertEqual(state.data[2], 0x12345654);
+}
+
+- (void)testABCDWithX {
+	_machine->set_program({
+		0xc302,		// ABCD D2, D1
+	});
+	auto state = _machine->get_processor_state();
+	state.data[1] = 0x12345645;
+	state.data[2] = 0x12345654;
+	state.status = Flag::Extend;
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssert(state.status & Flag::Carry);
+	XCTAssertEqual(state.data[1], 0x12345600);
+	XCTAssertEqual(state.data[2], 0x12345654);
+}
+
+- (void)testABCDOverflow {
+	_machine->set_program({
+		0xc302,		// ABCD D2, D1
+	});
+	auto state = _machine->get_processor_state();
+	state.data[1] = 0x1234563e;
+	state.data[2] = 0x1234563e;
+	state.status = Flag::Extend;
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssert(state.status & Flag::Overflow);
+	XCTAssertEqual(state.data[1], 0x12345683);
+	XCTAssertEqual(state.data[2], 0x1234563e);
+}
+
+- (void)testABCDPredecDifferent {
+	_machine->set_program({
+		0xc30a,		// ABCD -(A2), -(A1)
+	});
+	*_machine->ram_at(0x3000) = 0xa200;
+	*_machine->ram_at(0x4000) = 0x1900;
+
+	auto state = _machine->get_processor_state();
+	state.address[1] = 0x3001;
+	state.address[2] = 0x4001;
+	state.status = Flag::Extend;
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssert(state.status & Flag::Carry);
+	XCTAssert(state.status & Flag::Extend);
+	XCTAssertEqual(state.address[1], 0x3000);
+	XCTAssertEqual(state.address[2], 0x4000);
+	XCTAssertEqual(*_machine->ram_at(0x3000), 0x2200);
+	XCTAssertEqual(*_machine->ram_at(0x4000), 0x1900);
+}
+
+- (void)testABCDPredecSame {
+	_machine->set_program({
+		0xc309,		// ABCD -(A1), -(A1)
+	});
+	*_machine->ram_at(0x3000) = 0x19a2;
+
+	auto state = _machine->get_processor_state();
+	state.address[1] = 0x3002;
+	state.status = Flag::Extend;
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssert(state.status & Flag::Carry);
+	XCTAssert(state.status & Flag::Extend);
+	XCTAssertEqual(state.address[1], 0x3000);
+	XCTAssertEqual(*_machine->ram_at(0x3000), 0x22a2);
+}
+
+// MARK: NBCD
+
+- (void)performNBCDd1:(uint32_t)d1 ccr:(uint8_t)ccr {
+	_machine->set_program({
+		0x4801		// NBCD D1
+	});
+	auto state = _machine->get_processor_state();
+	state.status |= ccr;
+	state.data[1] = d1;
+
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	XCTAssertEqual(6, _machine->get_cycle_count());
+}
+
+- (void)testNBCD_Dn {
+	[self performNBCDd1:0x7a ccr:0];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], 0x20);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend | Flag::Carry | Flag::Overflow);
+}
+
+- (void)testNBCD_Dn_extend {
+	[self performNBCDd1:0x1234567a ccr:Flag::Extend | Flag::Zero];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], 0x1234561f);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend | Flag::Carry | Flag::Overflow);
+}
+
+- (void)testNBCD_Dn_zero {
+	[self performNBCDd1:0x12345600 ccr:Flag::Zero];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], 0x12345600);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Zero);
+}
+
+- (void)testNBCD_Dn_negative {
+	[self performNBCDd1:0x123456ff ccr:Flag::Extend | Flag::Zero];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], 0x1234569a);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend | Flag::Carry | Flag::Negative);
+}
+
+- (void)testNBCD_Dn_XXXw {
+	_machine->set_program({
+		0x4838, 0x3000		// NBCD ($3000).w
+	});
+	*_machine->ram_at(0x3000) = 0x0100;
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(16, _machine->get_cycle_count());
+	XCTAssertEqual(*_machine->ram_at(0x3000), 0x9900);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend | Flag::Carry | Flag::Negative);
+}
+
+// MARK: SBCD
+
+- (void)performSBCDd1:(uint32_t)d1 d2:(uint32_t)d2 ccr:(uint8_t)ccr {
+	_machine->set_program({
+		0x8302		// SBCD D2, D1
+	});
+	auto state = _machine->get_processor_state();
+	state.status |= ccr;
+	state.data[1] = d1;
+	state.data[2] = d2;
+
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssertEqual(6, _machine->get_cycle_count());
+	XCTAssertEqual(state.data[2], d2);
+}
+
+- (void)testSBCD_Dn {
+	[self performSBCDd1:0x12345689 d2:0xf745ff78 ccr:Flag::Zero];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], 0x12345611);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, 0);
+}
+
+- (void)testSBCD_Dn_zero {
+	[self performSBCDd1:0x123456ff d2:0xf745ffff ccr:Flag::Zero];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], 0x12345600);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Zero);
+}
+
+- (void)testSBCD_Dn_negative {
+	[self performSBCDd1:0x12345634 d2:0xf745ff45 ccr:Flag::Extend];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], 0x12345688);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend | Flag::Carry | Flag::Negative);
+}
+
+- (void)testSBCD_Dn_overflow {
+	[self performSBCDd1:0x123456a9 d2:0xf745ffff ccr:Flag::Extend];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], 0x12345643);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend | Flag::Carry | Flag::Overflow);
+}
+
+- (void)testSBCD_Dn_PreDec {
+	_machine->set_program({
+		0x830a		// SBCD -(A2), -(A1)
+	});
+	*_machine->ram_at(0x3000) = 0xa200;
+	*_machine->ram_at(0x4000) = 0x1900;
+	auto state = _machine->get_processor_state();
+	state.address[1] = 0x3001;
+	state.address[2] = 0x4001;
+	state.status |= Flag::Extend;
+
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssertEqual(18, _machine->get_cycle_count());
+	XCTAssertEqual(*_machine->ram_at(0x3000), 0x8200);
+	XCTAssertEqual(*_machine->ram_at(0x4000), 0x1900);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Negative);
+}
+
+@end

OSBindings/Mac/Clock SignalTests/68000ControlFlowTests.mm

@@ -0,0 +1,557 @@
+//
+//  68000ControlFlowTests.m
+//  Clock SignalTests
+//
+//  Created by Thomas Harte on 28/06/2019.
+//
+//  Largely ported from the tests of the Portable 68k Emulator.
+//
+
+#import <XCTest/XCTest.h>
+
+#include "TestRunner68000.hpp"
+
+
+@interface M68000ControlFlowTests : XCTestCase
+@end
+
+@implementation M68000ControlFlowTests {
+	std::unique_ptr<RAM68000> _machine;
+}
+
+- (void)setUp {
+    _machine.reset(new RAM68000());
+}
+
+- (void)tearDown {
+	_machine.reset();
+}
+
+// MARK: Bcc
+
+- (void)performBccb:(uint16_t)opcode {
+	_machine->set_program({
+		uint16_t(opcode | 6)	// Bcc.b +6
+	});
+
+	_machine->run_for_instructions(1);
+}
+
+- (void)performBccw:(uint16_t)opcode {
+	_machine->set_program({
+		opcode, 0x0006			// Bcc.w +6
+	});
+
+	_machine->run_for_instructions(1);
+}
+
+- (void)testBHIb {
+	[self performBccb:0x6200];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1008 + 4);
+	XCTAssertEqual(_machine->get_cycle_count(), 10);
+}
+
+- (void)testBLOb {
+	[self performBccb:0x6500];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1002 + 4);
+	XCTAssertEqual(_machine->get_cycle_count(), 8);
+}
+
+- (void)testBHIw {
+	[self performBccw:0x6200];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1008 + 4);
+	XCTAssertEqual(_machine->get_cycle_count(), 10);
+}
+
+- (void)testBLOw {
+	[self performBccw:0x6500];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1004 + 4);
+	XCTAssertEqual(_machine->get_cycle_count(), 12);
+}
+
+// MARK: BRA
+
+- (void)testBRAb {
+	_machine->set_program({
+		0x6004		// BRA.b +4
+	});
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1006 + 4);
+	XCTAssertEqual(_machine->get_cycle_count(), 10);
+}
+
+- (void)testBRAw {
+	_machine->set_program({
+		0x6000, 0x0004		// BRA.b +4
+	});
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1006 + 4);
+	XCTAssertEqual(_machine->get_cycle_count(), 10);
+}
+
+// MARK: BSR
+
+- (void)testBSRw {
+	_machine->set_program({
+		0x6100, 0x0006		// BSR.w $1008
+	});
+	_machine->set_initial_stack_pointer(0x3000);
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1008 + 4);
+	XCTAssertEqual(state.stack_pointer(), 0x2ffc);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, 0);
+	XCTAssertEqual(*_machine->ram_at(0x2ffc), 0);
+	XCTAssertEqual(*_machine->ram_at(0x2ffe), 0x1004);
+
+	XCTAssertEqual(_machine->get_cycle_count(), 18);
+}
+
+- (void)testBSRb {
+	_machine->set_program({
+		0x6106		// BSR.b $1008
+	});
+	_machine->set_initial_stack_pointer(0x3000);
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1008 + 4);
+	XCTAssertEqual(state.stack_pointer(), 0x2ffc);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, 0);
+	XCTAssertEqual(*_machine->ram_at(0x2ffc), 0);
+	XCTAssertEqual(*_machine->ram_at(0x2ffe), 0x1002);
+
+	XCTAssertEqual(_machine->get_cycle_count(), 18);
+}
+
+// MARK: CHK
+
+- (void)performCHKd1:(uint32_t)d1 d2:(uint32_t)d2 {
+	_machine->set_program({
+		0x4581		// CHK D1, D2
+	});
+	auto state = _machine->get_processor_state();
+	state.data[1] = d1;
+	state.data[2] = d2;
+	state.status |= Flag::ConditionCodes;
+
+	_machine->set_initial_stack_pointer(0);
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[1], d1);
+	XCTAssertEqual(state.data[2], d2);
+}
+
+- (void)testCHK_1111v1111 {
+	[self performCHKd1:0x1111 d2:0x1111];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1002 + 4);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend);
+	XCTAssertEqual(10, _machine->get_cycle_count());
+}
+
+- (void)testCHK_1111v0000 {
+	[self performCHKd1:0x1111 d2:0x0000];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1002 + 4);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend | Flag::Zero);
+	XCTAssertEqual(10, _machine->get_cycle_count());
+}
+
+- (void)testCHK_8000v8001 {
+	[self performCHKd1:0x8000 d2:0x8001];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertNotEqual(state.program_counter, 0x1002 + 4);
+	XCTAssertEqual(state.stack_pointer(), 0xfffffffa);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend);
+	XCTAssertEqual(42, _machine->get_cycle_count());
+}
+
+- (void)testCHK_8000v8000 {
+	[self performCHKd1:0x8000 d2:0x8000];
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertNotEqual(state.program_counter, 0x1002 + 4);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::Extend | Flag::Negative);
+	XCTAssertEqual(44, _machine->get_cycle_count());
+}
+
+// MARK: DBcc
+
+- (void)performDBccTestOpcode:(uint16_t)opcode status:(uint16_t)status d2Outcome:(uint32_t)d2Output {
+	_machine->set_program({
+		opcode, 0x0008		// DBcc D2, +8
+	});
+	auto state = _machine->get_processor_state();
+	state.status = status;
+	state.data[2] = 1;
+
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssertEqual(state.data[2], d2Output);
+	XCTAssertEqual(state.status, status);
+}
+
+- (void)testDBT {
+	[self performDBccTestOpcode:0x50ca status:0 d2Outcome:1];
+}
+
+- (void)testDBF {
+	[self performDBccTestOpcode:0x51ca status:0 d2Outcome:0];
+}
+
+- (void)testDBHI {
+	[self performDBccTestOpcode:0x52ca status:0 d2Outcome:1];
+}
+
+- (void)testDBHI_Carry {
+	[self performDBccTestOpcode:0x52ca status:Flag::Carry d2Outcome:0];
+}
+
+- (void)testDBHI_Zero {
+	[self performDBccTestOpcode:0x52ca status:Flag::Zero d2Outcome:0];
+}
+
+- (void)testDBLS_CarryOverflow {
+	[self performDBccTestOpcode:0x53ca status:Flag::Carry | Flag::Overflow d2Outcome:1];
+}
+
+- (void)testDBLS_Carry {
+	[self performDBccTestOpcode:0x53ca status:Flag::Carry d2Outcome:1];
+}
+
+- (void)testDBLS_Overflow {
+	[self performDBccTestOpcode:0x53ca status:Flag::Overflow d2Outcome:0];
+}
+
+- (void)testDBCC_Carry {
+	[self performDBccTestOpcode:0x54ca status:Flag::Carry d2Outcome:0];
+}
+
+- (void)testDBCC {
+	[self performDBccTestOpcode:0x54ca status:0 d2Outcome:1];
+}
+
+- (void)testDBCS {
+	[self performDBccTestOpcode:0x55ca status:0 d2Outcome:0];
+}
+
+- (void)testDBCS_Carry {
+	[self performDBccTestOpcode:0x55ca status:Flag::Carry d2Outcome:1];
+}
+
+- (void)testDBNE {
+	[self performDBccTestOpcode:0x56ca status:0 d2Outcome:1];
+}
+
+- (void)testDBNE_Zero {
+	[self performDBccTestOpcode:0x56ca status:Flag::Zero d2Outcome:0];
+}
+
+- (void)testDBEQ {
+	[self performDBccTestOpcode:0x57ca status:0 d2Outcome:0];
+}
+
+- (void)testDBEQ_Zero {
+	[self performDBccTestOpcode:0x57ca status:Flag::Zero d2Outcome:1];
+}
+
+- (void)testDBVC {
+	[self performDBccTestOpcode:0x58ca status:0 d2Outcome:1];
+}
+
+- (void)testDBVC_Overflow {
+	[self performDBccTestOpcode:0x58ca status:Flag::Overflow d2Outcome:0];
+}
+
+- (void)testDBVS {
+	[self performDBccTestOpcode:0x59ca status:0 d2Outcome:0];
+}
+
+- (void)testDBVS_Overflow {
+	[self performDBccTestOpcode:0x59ca status:Flag::Overflow d2Outcome:1];
+}
+
+- (void)testDBPL {
+	[self performDBccTestOpcode:0x5aca status:0 d2Outcome:1];
+}
+
+- (void)testDBPL_Negative {
+	[self performDBccTestOpcode:0x5aca status:Flag::Negative d2Outcome:0];
+}
+
+- (void)testDBMI {
+	[self performDBccTestOpcode:0x5bca status:0 d2Outcome:0];
+}
+
+- (void)testDBMI_Negative {
+	[self performDBccTestOpcode:0x5bca status:Flag::Negative d2Outcome:1];
+}
+
+- (void)testDBGE_NegativeOverflow {
+	[self performDBccTestOpcode:0x5cca status:Flag::Negative | Flag::Overflow d2Outcome:1];
+}
+
+- (void)testDBGE {
+	[self performDBccTestOpcode:0x5cca status:0 d2Outcome:1];
+}
+
+- (void)testDBGE_Negative {
+	[self performDBccTestOpcode:0x5cca status:Flag::Negative d2Outcome:0];
+}
+
+- (void)testDBGE_Overflow {
+	[self performDBccTestOpcode:0x5cca status:Flag::Overflow d2Outcome:0];
+}
+
+- (void)testDBLT_NegativeOverflow {
+	[self performDBccTestOpcode:0x5dca status:Flag::Negative | Flag::Overflow d2Outcome:0];
+}
+
+- (void)testDBLT {
+	[self performDBccTestOpcode:0x5dca status:0 d2Outcome:0];
+}
+
+- (void)testDBLT_Negative {
+	[self performDBccTestOpcode:0x5dca status:Flag::Negative d2Outcome:1];
+}
+
+- (void)testDBLT_Overflow {
+	[self performDBccTestOpcode:0x5dca status:Flag::Overflow d2Outcome:1];
+}
+
+- (void)testDBGT {
+	[self performDBccTestOpcode:0x5eca status:0 d2Outcome:1];
+}
+
+- (void)testDBGT_ZeroNegativeOverflow {
+	[self performDBccTestOpcode:0x5eca status:Flag::Zero | Flag::Negative | Flag::Overflow d2Outcome:0];
+}
+
+- (void)testDBGT_NegativeOverflow {
+	[self performDBccTestOpcode:0x5eca status:Flag::Negative | Flag::Overflow d2Outcome:1];
+}
+
+- (void)testDBGT_Zero {
+	[self performDBccTestOpcode:0x5eca status:Flag::Zero d2Outcome:0];
+}
+
+- (void)testDBLE {
+	[self performDBccTestOpcode:0x5fca status:0 d2Outcome:0];
+}
+
+- (void)testDBLE_Zero {
+	[self performDBccTestOpcode:0x5fca status:Flag::Zero d2Outcome:1];
+}
+
+- (void)testDBLE_Negative {
+	[self performDBccTestOpcode:0x5fca status:Flag::Negative d2Outcome:1];
+}
+
+- (void)testDBLE_NegativeOverflow {
+	[self performDBccTestOpcode:0x5fca status:Flag::Negative | Flag::Overflow d2Outcome:0];
+}
+
+/* Further DBF tests omitted; they seemed to be duplicative, assuming I'm not suffering a failure of comprehension. */
+
+// MARK: JMP
+
+- (void)testJMP_A1 {
+	_machine->set_program({
+		0x4ed1		// JMP (A1)
+	});
+
+	auto state = _machine->get_processor_state();
+	state.address[1] = 0x3000;
+
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssertEqual(state.address[1], 0x3000);
+	XCTAssertEqual(state.program_counter, 0x3000 + 4);
+	XCTAssertEqual(8, _machine->get_cycle_count());
+}
+
+- (void)testJMP_PC {
+	_machine->set_program({
+		0x4efa, 0x000a		// JMP PC+a (i.e. to 0x100c)
+	});
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x100c + 4);
+	XCTAssertEqual(10, _machine->get_cycle_count());
+}
+
+// MARK: JSR
+
+- (void)testJSR_PC {
+	_machine->set_program({
+		0x4eba, 0x000a		// JSR (+a)PC		; JSR to $100c
+	});
+	_machine->set_initial_stack_pointer(0x2000);
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.stack_pointer(), 0x1ffc);
+	XCTAssertEqual(state.program_counter, 0x100c + 4);
+	XCTAssertEqual(*_machine->ram_at(0x1ffc), 0x0000);
+	XCTAssertEqual(*_machine->ram_at(0x1ffe), 0x1004);
+	XCTAssertEqual(18, _machine->get_cycle_count());
+}
+
+- (void)testJSR_XXXl {
+	_machine->set_program({
+		0x4eb9, 0x0000, 0x1008		// JSR ($1008).l
+	});
+	_machine->set_initial_stack_pointer(0x2000);
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.stack_pointer(), 0x1ffc);
+	XCTAssertEqual(state.program_counter, 0x1008 + 4);
+	XCTAssertEqual(*_machine->ram_at(0x1ffc), 0x0000);
+	XCTAssertEqual(*_machine->ram_at(0x1ffe), 0x1006);
+	XCTAssertEqual(20, _machine->get_cycle_count());
+}
+
+// MARK: NOP
+
+- (void)testNOP {
+	_machine->set_program({
+		0x4e71		// NOP
+	});
+	_machine->run_for_instructions(1);
+	XCTAssertEqual(4, _machine->get_cycle_count());
+}
+
+// MARK: RTR
+
+- (void)testRTR {
+	_machine->set_program({
+		0x4e77		// RTR
+	});
+	_machine->set_initial_stack_pointer(0x2000);
+	*_machine->ram_at(0x2000) = 0x7fff;
+	*_machine->ram_at(0x2002) = 0;
+	*_machine->ram_at(0x2004) = 0xc;
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.stack_pointer(), 0x2006);
+	XCTAssertEqual(state.program_counter, 0x10);
+	XCTAssertEqual(state.status & Flag::ConditionCodes, Flag::ConditionCodes);
+	XCTAssertEqual(20, _machine->get_cycle_count());
+}
+
+// MARK: RTS
+
+- (void)testRTS {
+	_machine->set_program({
+		0x4e75		// RTS
+	});
+	_machine->set_initial_stack_pointer(0x2000);
+	*_machine->ram_at(0x2000) = 0x0000;
+	*_machine->ram_at(0x2002) = 0x000c;
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.stack_pointer(), 0x2004);
+	XCTAssertEqual(state.program_counter, 0x000c + 4);
+	XCTAssertEqual(16, _machine->get_cycle_count());
+}
+
+// MARK: TRAP
+
+- (void)testTRAP {
+	_machine->set_program({
+		0x4e41		// TRAP #1
+	});
+	auto state = _machine->get_processor_state();
+	state.status = 0x700;
+	state.user_stack_pointer = 0x200;
+	state.supervisor_stack_pointer = 0x206;
+	*_machine->ram_at(0x84) = 0xfffe;
+	*_machine->ram_at(0xfffe) = 0x4e71;
+
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssertEqual(state.status, 0x2700);
+	XCTAssertEqual(*_machine->ram_at(0x200), 0x700);
+	XCTAssertEqual(*_machine->ram_at(0x202), 0x0000);
+	XCTAssertEqual(*_machine->ram_at(0x204), 0x1002);
+	XCTAssertEqual(state.supervisor_stack_pointer, 0x200);
+	XCTAssertEqual(34, _machine->get_cycle_count());
+}
+
+// MARK: TRAPV
+
+- (void)testTRAPV_taken {
+	_machine->set_program({
+		0x4e76		// TRAPV
+	});
+	_machine->set_initial_stack_pointer(0x206);
+
+	auto state = _machine->get_processor_state();
+	state.status = 0x702;
+	state.supervisor_stack_pointer = 0x206;
+	*_machine->ram_at(0x1e) = 0xfffe;
+	*_machine->ram_at(0xfffe) = 0x4e71;
+
+	_machine->set_processor_state(state);
+	_machine->run_for_instructions(1);
+
+	state = _machine->get_processor_state();
+	XCTAssertEqual(state.status, 0x2702);
+	XCTAssertEqual(state.stack_pointer(), 0x200);
+	XCTAssertEqual(*_machine->ram_at(0x202), 0x0000);
+	XCTAssertEqual(*_machine->ram_at(0x204), 0x1002);
+	XCTAssertEqual(*_machine->ram_at(0x200), 0x702);
+	XCTAssertEqual(34, _machine->get_cycle_count());
+}
+
+- (void)testTRAPV_untaken {
+	_machine->set_program({
+		0x4e76		// TRAPV
+	});
+
+	_machine->run_for_instructions(1);
+
+	const auto state = _machine->get_processor_state();
+	XCTAssertEqual(state.program_counter, 0x1002 + 4);
+	XCTAssertEqual(4, _machine->get_cycle_count());
+}
+
+@end