With some time additions to the 6522, starts wiring in Macintosh audio.

The audio buffer is also the disk motor buffer, so this is preparatory to further disk work.

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()															{}
 };
 
 /*!
@@ -108,12 +114,17 @@ template <class T> class MOS6522: public MOS6522Storage {
 		/// @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);
 

Components/6522/Implementation/6522Implementation.hpp

@@ -37,6 +37,8 @@ template <typename T> void MOS6522<T>::set_register(int address, uint8_t value)
 		case 0x0:	// Write Port B.
 			// Store locally and communicate outwards.
 			registers_.output[1] = value;
+
+			bus_handler_.run_for(time_since_bus_handler_call_.flush());
 			bus_handler_.set_port_output(Port::B, value, registers_.data_direction[1]);
 
 			registers_.interrupt_flags &= ~(InterruptFlag::CB1ActiveEdge | ((registers_.peripheral_control&0x20) ? 0 : InterruptFlag::CB2ActiveEdge));
@@ -45,6 +47,8 @@ template <typename T> void MOS6522<T>::set_register(int address, uint8_t value)
 		case 0xf:
 		case 0x1:	// Write Port A.
 			registers_.output[0] = value;
+
+			bus_handler_.run_for(time_since_bus_handler_call_.flush());
 			bus_handler_.set_port_output(Port::A, value, registers_.data_direction[0]);
 
 			if(handshake_modes_[1] != HandshakeMode::None) {
@@ -193,7 +197,8 @@ 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());
+	const uint8_t input = bus_handler_.get_port_input(port);
 	return (input & ~output_mask) | (output & output_mask);
 }
 
@@ -206,6 +211,8 @@ 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());
 		bus_handler_.set_interrupt_status(new_interrupt_status);
 	}
 }
@@ -251,6 +258,8 @@ template <typename T> void MOS6522<T>::set_control_line_input(Port port, Line li
 }
 
 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];
 
@@ -281,6 +290,8 @@ template <typename T> void MOS6522<T>::do_phase2() {
 }
 
 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;
@@ -339,6 +350,11 @@ template <typename T> void MOS6522<T>::run_for(const HalfCycles half_cycles) {
 	}
 }
 
+template <typename T> void MOS6522<T>::flush() {
+	bus_handler_.run_for(time_since_bus_handler_call_.flush());
+	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();
@@ -363,6 +379,7 @@ template <typename T> void MOS6522<T>::set_control_line_output(Port port, Line l
 	// control line is actually in output mode.
 	control_outputs_[port].lines[line] = value;
 	if(registers_.peripheral_control & (0x08 << (port * 4))) {
+		bus_handler_.run_for(time_since_bus_handler_call_.flush());
 		bus_handler_.set_control_line_output(port, line, value);
 	}
 }

Components/DiskII/IWM.cpp

@@ -38,11 +38,14 @@ uint8_t IWM::read(int address) {
 	// 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 thoughts: I'm unclear on how passing data from RD/SENSE is conflated with reading "any of the disk
-	// registers", but the text reads as though the access happens internally but isn't passed on in the case
-	// of Q6 and Q7 being in the incorrect state.
+	// 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.
 
-	printf("Read %d: ", address&1);
+	if(address&1) {
+		return 0xff;
+	}
 
 	switch(state_ & (Q6 | Q7 | ENABLE)) {
 		default:
@@ -73,7 +76,7 @@ uint8_t IWM::read(int address) {
 			printf("Reading status ([%d] including ", (state_&DRIVESEL) ? 2 : 1);
 
 			// Determine the SENSE input.
-			uint8_t sense = 0;
+			uint8_t sense = 0x80;
 			switch(state_ & (CA2 | CA1 | CA0 | SEL)) {
 				default:
 					printf("unknown)\n");
@@ -85,7 +88,6 @@ uint8_t IWM::read(int address) {
 
 				case SEL:				// Disk in place.
 					printf("disk in place)\n");
-					sense = 0x80;
 				break;
 
 				case CA0:				// Disk head stepping.

Machines/Apple/Macintosh/Audio.cpp

@@ -0,0 +1,50 @@
+//
+//  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;
+
+Audio::Audio(Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_(task_queue) {}
+
+// MARK: - Inputs
+
+void Audio::post_sample(uint8_t sample) {
+	const auto write_pointer = sample_queue_.write_pointer.load();
+//	const auto pointers
+
+	const auto read_pointer = sample_queue_.read_pointer.load();
+}
+
+void Audio::set_volume(int volume) {
+	task_queue_.defer([=] () {
+		volume_ = volume;
+	});
+}
+
+void Audio::set_enabled(bool on) {
+	task_queue_.defer([=] () {
+		is_enabled_ = on;
+	});
+}
+
+// MARK: - Output generation
+
+bool Audio::is_zero_level() {
+	return !volume_ || !is_enabled_;
+}
+
+void Audio::set_sample_volume_range(std::int16_t range) {
+	volume_multiplier_ = range / 7;
+}
+
+void Audio::get_samples(std::size_t number_of_samples, int16_t *target) {
+//	if(is_zero_level()) {
+//		memset(target, 0, number_of_samples * sizeof(int16_t));
+//	}
+}

Machines/Apple/Macintosh/Audio.hpp

@@ -0,0 +1,78 @@
+//
+//  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 "../../../Outputs/Speaker/Implementation/SampleSource.hpp"
+#include "../../../Concurrency/AsyncTaskQueue.hpp"
+#include "../../../ClockReceiver/ClockReceiver.hpp"
+
+#include <array>
+#include <atomic>
+
+namespace Apple {
+namespace Macintosh {
+
+/*!
+	Implements the Macintosh's audio output hardware, using a
+	combination
+*/
+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, 2048> buffer;
+			std::atomic<int> read_pointer, write_pointer;
+		} sample_queue_;
+
+		// Stateful variables, modified from the audio generation
+		// thread only.
+		int volume_ = 0;
+		bool is_enabled_ = false;
+
+		std::int16_t volume_multiplier_ = 0;
+};
+
+}
+}
+
+#endif /* Audio_hpp */

Machines/Apple/Macintosh/Macintosh.cpp

@@ -10,6 +10,7 @@
 
 #include <array>
 
+#include "Audio.hpp"
 #include "Keyboard.hpp"
 #include "RealTimeClock.hpp"
 #include "Video.hpp"
@@ -18,9 +19,10 @@
 
 //#define LOG_TRACE
 
-#include "../../../Processors/68000/68000.hpp"
 #include "../../../Components/6522/6522.hpp"
 #include "../../../Components/DiskII/IWM.hpp"
+#include "../../../Outputs/Speaker/Implementation/LowpassSpeaker.hpp"
+#include "../../../Processors/68000/68000.hpp"
 
 #include "../../Utility/MemoryPacker.hpp"
 
@@ -42,7 +44,7 @@ class ConcreteMachine:
 		 	mc68000_(*this),
 		 	video_(ram_.data()),
 		 	via_(via_port_handler_),
-		 	via_port_handler_(*this, clock_, keyboard_, video_, iwm_),
+		 	via_port_handler_(*this, clock_, keyboard_, video_, audio_, iwm_),
 		 	iwm_(CLOCK_RATE) {
 
 			// Grab a copy of the ROM and convert it into big-endian data.
@@ -62,7 +64,7 @@ class ConcreteMachine:
 		}
 
 		Outputs::Speaker::Speaker *get_speaker() override {
-			return nullptr;
+			return &audio_.speaker;
 		}
 
 		void run_for(const Cycles cycles) override {
@@ -227,7 +229,14 @@ class ConcreteMachine:
 		}
 
 		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.
 //			video_.run_for(time_since_video_update_.flush());
+
+			// As above: flush audio after video.
+			audio_.queue.flush();
 		}
 
 		void set_rom_is_overlay(bool rom_is_overlay) {
@@ -250,10 +259,23 @@ class ConcreteMachine:
 			}
 		};
 
+		struct Audio {
+			Concurrency::DeferringAsyncTaskQueue queue;
+			Apple::Macintosh::Audio audio;
+			Outputs::Speaker::LowpassSpeaker<Apple::Macintosh::Audio> speaker;
+			HalfCycles time_since_update;
+
+			Audio() : audio(queue), speaker(audio) {}
+
+			void flush() {
+				speaker.run_for(queue, time_since_update.flush_cycles());
+			}
+		};
+
 		class VIAPortHandler: public MOS::MOS6522::PortHandler {
 			public:
-				VIAPortHandler(ConcreteMachine &machine, RealTimeClock &clock, Keyboard &keyboard, Video &video, IWM &iwm) :
-					machine_(machine), clock_(clock), keyboard_(keyboard), video_(video), iwm_(iwm) {}
+				VIAPortHandler(ConcreteMachine &machine, RealTimeClock &clock, Keyboard &keyboard, Video &video, Audio &audio, IWM &iwm) :
+					machine_(machine), clock_(clock), keyboard_(keyboard), video_(video), audio_(audio), iwm_(iwm) {}
 
 				using Port = MOS::MOS6522::Port;
 				using Line = MOS::MOS6522::Line;
@@ -274,15 +296,16 @@ class ConcreteMachine:
 									b3:	0 = use alternate sound buffer, 1 = use ordinary sound buffer
 									b2–b0:	audio output volume
 							*/
-//							printf("6522 A: %02x\n", value);
-
 							iwm_.flush();
 							iwm_.iwm.set_select(!(value & 0x20));
 
 							machine_.set_use_alternate_screen_buffer(!(value & 0x40));
 							machine_.set_rom_is_overlay(!!(value & 0x10));
 
-							// TODO: alternate sound buffer, and audio output volume.
+							audio_.flush();
+							audio_.audio.set_volume(value & 7);
+
+							// TODO: alternate sound buffer.
 						break;
 
 						case Port::B:
@@ -300,7 +323,8 @@ class ConcreteMachine:
 							if(value & 0x4) clock_.abort();
 							else clock_.set_input(!!(value & 0x2), !!(value & 0x1));
 
-							// TODO: sound enabled/disabled.
+							audio_.flush();
+							audio_.audio.set_enabled(!!(value & 0x80));
 						break;
 					}
 				}
@@ -336,6 +360,7 @@ class ConcreteMachine:
 				RealTimeClock &clock_;
 				Keyboard &keyboard_;
 				Video &video_;
+				Audio &audio_;
 				IWM &iwm_;
 		};
 
@@ -343,7 +368,9 @@ class ConcreteMachine:
 		std::array<uint16_t, 64*1024> ram_;
 
 		CPU::MC68000::Processor<ConcreteMachine, true> mc68000_;
+
 		Video video_;
+		Audio audio_;
 
 		RealTimeClock clock_;
 		Keyboard keyboard_;

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_;
@@ -434,7 +434,6 @@ 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 +455,7 @@ template <Analyser::Static::Oric::Target::DiskInterface disk_interface> class Co
 
 		forceinline void flush() {
 			update_video();
-			via_port_handler_.flush();
+			via_.flush();
 			flush_diskii();
 		}
 

OSBindings/Mac/Clock Signal.xcodeproj/project.pbxproj

@@ -296,6 +296,7 @@
 		4B924E991E74D22700B76AF1 /* AtariStaticAnalyserTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B924E981E74D22700B76AF1 /* AtariStaticAnalyserTests.mm */; };
 		4B9252CE1E74D28200B76AF1 /* Atari ROMs in Resources */ = {isa = PBXBuildFile; fileRef = 4B9252CD1E74D28200B76AF1 /* Atari ROMs */; };
 		4B92EACA1B7C112B00246143 /* 6502TimingTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = 4B92EAC91B7C112B00246143 /* 6502TimingTests.swift */; };
+		4B9378E422A199C600973513 /* Audio.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 4B9378E222A199C600973513 /* Audio.cpp */; };
 		4B98A05E1FFAD3F600ADF63B /* CSROMFetcher.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B98A05D1FFAD3F600ADF63B /* CSROMFetcher.mm */; };
 		4B98A05F1FFAD62400ADF63B /* CSROMFetcher.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B98A05D1FFAD3F600ADF63B /* CSROMFetcher.mm */; };
 		4B98A0611FFADCDE00ADF63B /* MSXStaticAnalyserTests.mm in Sources */ = {isa = PBXBuildFile; fileRef = 4B98A0601FFADCDE00ADF63B /* MSXStaticAnalyserTests.mm */; };
@@ -1031,6 +1032,8 @@
 		4B924E981E74D22700B76AF1 /* AtariStaticAnalyserTests.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = AtariStaticAnalyserTests.mm; sourceTree = "<group>"; };
 		4B9252CD1E74D28200B76AF1 /* Atari ROMs */ = {isa = PBXFileReference; lastKnownFileType = folder; path = "Atari ROMs"; sourceTree = "<group>"; };
 		4B92EAC91B7C112B00246143 /* 6502TimingTests.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = 6502TimingTests.swift; sourceTree = "<group>"; };
+		4B9378E222A199C600973513 /* Audio.cpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.cpp; path = Audio.cpp; sourceTree = "<group>"; };
+		4B9378E322A199C600973513 /* Audio.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Audio.hpp; sourceTree = "<group>"; };
 		4B95FA9C1F11893B0008E395 /* ZX8081OptionsPanel.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = ZX8081OptionsPanel.swift; sourceTree = "<group>"; };
 		4B961408222760E0001A7BF2 /* Screenshot.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = Screenshot.hpp; sourceTree = "<group>"; };
 		4B98A05C1FFAD3F600ADF63B /* CSROMFetcher.hpp */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.cpp.h; path = CSROMFetcher.hpp; sourceTree = "<group>"; };
@@ -3065,12 +3068,14 @@
 		4BCE0057227CFFCA000CA200 /* Macintosh */ = {
 			isa = PBXGroup;
 			children = (
+				4B9378E222A199C600973513 /* Audio.cpp */,
 				4BCE0058227CFFCA000CA200 /* Macintosh.cpp */,
 				4BCE005E227D39AB000CA200 /* Video.cpp */,
+				4B9378E322A199C600973513 /* Audio.hpp */,
+				4BDB3D8522833321002D3CEE /* Keyboard.hpp */,
 				4BCE0059227CFFCA000CA200 /* Macintosh.hpp */,
 				4BD0692B22828A2D00D2A54F /* RealTimeClock.hpp */,
 				4BCE005F227D39AB000CA200 /* Video.hpp */,
-				4BDB3D8522833321002D3CEE /* Keyboard.hpp */,
 			);
 			path = Macintosh;
 			sourceTree = "<group>";
@@ -3254,11 +3259,11 @@
 		4BF660691F281573002CB053 /* ClockReceiver */ = {
 			isa = PBXGroup;
 			children = (
+				4B8A7E85212F988200F2BBC6 /* ClockDeferrer.hpp */,
+				4BB146C61F49D7D700253439 /* ClockingHintSource.hpp */,
 				4BF6606A1F281573002CB053 /* ClockReceiver.hpp */,
 				4BB06B211F316A3F00600C7A /* ForceInline.hpp */,
-				4BB146C61F49D7D700253439 /* ClockingHintSource.hpp */,
 				4B449C942063389900A095C8 /* TimeTypes.hpp */,
-				4B8A7E85212F988200F2BBC6 /* ClockDeferrer.hpp */,
 			);
 			name = ClockReceiver;
 			path = ../../ClockReceiver;
@@ -3905,6 +3910,7 @@
 				4B2BFC5F1D613E0200BA3AA9 /* TapePRG.cpp in Sources */,
 				4BC9DF4F1D04691600F44158 /* 6560.cpp in Sources */,
 				4B59199C1DAC6C46005BB85C /* OricTAP.cpp in Sources */,
+				4B9378E422A199C600973513 /* Audio.cpp in Sources */,
 				4B89451E201967B4007DE474 /* Tape.cpp in Sources */,
 				4BAF2B4E2004580C00480230 /* DMK.cpp in Sources */,
 				4BB697CE1D4BA44400248BDF /* CommodoreGCR.cpp in Sources */,