Gives the SN76489 its proper dividers and personalities.

Components/SN76489/SN76489.cpp

@@ -12,7 +12,7 @@
 
 using namespace TI;
 
-SN76489::SN76489(Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_(task_queue) {
+SN76489::SN76489(Personality personality, Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_(task_queue) {
 	// Build a volume table.
 	double multiplier = pow(10.0, -0.1);
 	double volume = 8191.0f;
@@ -22,6 +22,21 @@ SN76489::SN76489(Concurrency::DeferringAsyncTaskQueue &task_queue) : task_queue_
 	}
 	volumes_[15] = 0;
 	evaluate_output_volume();
+
+	switch(personality) {
+		case Personality::SN76494:
+			master_divider_period_ = 2;
+			shifter_is_16bit_ = false;
+		break;
+		case Personality::SN76489:
+			master_divider_period_ = 16;
+			shifter_is_16bit_ = false;
+		break;
+		case Personality::SMS:
+			master_divider_period_ = 16;
+			shifter_is_16bit_ = true;
+		break;
+	}
 }
 
 void SN76489::set_register(uint8_t value) {
@@ -72,10 +87,8 @@ void SN76489::evaluate_output_volume() {
 }
 
 void SN76489::get_samples(std::size_t number_of_samples, std::int16_t *target) {
-	// For now: assume a divide by eight.
-
 	std::size_t c = 0;
-	while((master_divider_&7) && c < number_of_samples) {
+	while((master_divider_& (master_divider_period_ - 1)) && c < number_of_samples) {
 		target[c] = output_volume_;
 		master_divider_++;
 		c++;
@@ -124,12 +137,12 @@ void SN76489::get_samples(std::size_t number_of_samples, std::int16_t *target) {
 
 		evaluate_output_volume();
 
-		for(int ic = 0; ic < 8 && c < number_of_samples; ic++) {
+		for(int ic = 0; ic < master_divider_period_ && c < number_of_samples; ++ic) {
 			target[c] = output_volume_;
 			c++;
 			master_divider_++;
 		}
 	}
 
-	master_divider_ &= 7;
+	master_divider_ &= (master_divider_period_ - 1);
 }

Components/SN76489/SN76489.hpp

@@ -16,8 +16,14 @@ namespace TI {
 
 class SN76489: public Outputs::Speaker::SampleSource {
 	public:
+		enum class Personality {
+			SN76489,
+			SN76494,
+			SMS
+		};
+
 		/// Creates a new SN76489.
-		SN76489(Concurrency::DeferringAsyncTaskQueue &task_queue);
+		SN76489(Personality personality, Concurrency::DeferringAsyncTaskQueue &task_queue);
 
 		/// Writes a new value to the SN76489.
 		void set_register(uint8_t value);
@@ -26,8 +32,9 @@ class SN76489: public Outputs::Speaker::SampleSource {
 		void get_samples(std::size_t number_of_samples, std::int16_t *target);
 
 	private:
-		std::size_t master_divider_ = 0;
+		int master_divider_ = 0;
-		int16_t output_volume_ = 0;;
+		int master_divider_period_ = 16;
+		int16_t output_volume_ = 0;
 		void evaluate_output_volume();
 		int volumes_[16];
 

Machines/ColecoVision/ColecoVision.cpp

@@ -107,9 +107,10 @@ class ConcreteMachine:
 	public:
 		ConcreteMachine() :
 			z80_(*this),
-			sn76489_(audio_queue_),
+			sn76489_(TI::SN76489::Personality::SN76489, audio_queue_),
 			speaker_(sn76489_) {
-			speaker_.set_input_rate(3579545.0f / 2.0f);	// TODO: try to find out whether this is correct.
+//			speaker_.set_input_rate(3579545.0f);
+			speaker_.set_input_rate(3579545.0f / 2.0f);
 			set_clock_rate(3579545);
 			joysticks_.emplace_back(new Joystick);
 			joysticks_.emplace_back(new Joystick);
@@ -158,9 +159,7 @@ class ConcreteMachine:
 		bool set_rom_fetcher(const std::function<std::vector<std::unique_ptr<std::vector<uint8_t>>>(const std::string &machine, const std::vector<std::string> &names)> &roms_with_names) override {
 			auto roms = roms_with_names(
 				"ColecoVision",
-				{
+				{ "coleco.rom" });
-					"coleco.rom"
-				});
 
 			if(!roms[0]) return false;
 
@@ -172,18 +171,6 @@ class ConcreteMachine:
 
 		// MARK: Z80::BusHandler
 		forceinline HalfCycles perform_machine_cycle(const CPU::Z80::PartialMachineCycle &cycle) {
-			time_since_vdp_update_ += cycle.length;
-			time_since_sn76489_update_ += cycle.length;
-
-			if(time_until_interrupt_ > 0) {
-				time_until_interrupt_ -= cycle.length;
-				if(time_until_interrupt_ <= HalfCycles(0)) {
-					z80_.set_non_maskable_interrupt_line(true, time_until_interrupt_);
-					update_video();
-					time_until_interrupt_ = vdp_->get_time_until_interrupt();
-				}
-			}
-
 			uint16_t address = cycle.address ? *cycle.address : 0x0000;
 			switch(cycle.operation) {
 				case CPU::Z80::PartialMachineCycle::ReadOpcode:
@@ -256,11 +243,21 @@ class ConcreteMachine:
 				default: break;
 			}
 
+			time_since_vdp_update_ += cycle.length;
+			time_since_sn76489_update_ += cycle.length;
+
+			if(time_until_interrupt_ > 0) {
+				time_until_interrupt_ -= cycle.length;
+				if(time_until_interrupt_ <= HalfCycles(0)) {
+					z80_.set_non_maskable_interrupt_line(true, time_until_interrupt_);
+				}
+			}
+
 			return HalfCycles(0);
 		}
 
 		void flush() {
-			vdp_->run_for(time_since_vdp_update_.flush());
+			update_video();
 			update_audio();
 			audio_queue_.perform();
 		}
@@ -268,6 +265,7 @@ class ConcreteMachine:
 	private:
 		void update_audio() {
 			speaker_.run_for(audio_queue_, time_since_sn76489_update_.divide_cycles(Cycles(2)));
+//			speaker_.run_for(audio_queue_, time_since_sn76489_update_.cycles());
 		}
 		void update_video() {
 			vdp_->run_for(time_since_vdp_update_.flush());