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◆ main openmsx / src / sound / MSXTurboRPCM.cc
3.5 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
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#include "MSXTurboRPCM.hh"
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#include "MSXMixer.hh"
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#include "MSXMotherBoard.hh"
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#include "serialize.hh"
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#include "narrow.hh"
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#include "unreachable.hh"
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namespace openmsx {
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MSXTurboRPCM::MSXTurboRPCM(const DeviceConfig& config)
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	: MSXDevice(config)
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	, mixer(getMotherBoard().getMSXMixer())
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	, connector(getPluggingController(), "pcminput")
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	, dac("PCM", "Turbo-R PCM", config)
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	, reference(getCurrentTime())
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{
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	reset(getCurrentTime());
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}
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MSXTurboRPCM::~MSXTurboRPCM()
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{
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	hardwareMute(false);
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}
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void MSXTurboRPCM::reset(EmuTime time)
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{
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	reference.reset(time);
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	status = 0;
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	DValue = 0x80; // TODO correct initial value?
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	hold = 0x80; // avoid UMR
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	dac.reset(time);
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	hardwareMute(false);
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}
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byte MSXTurboRPCM::readIO(uint16_t port, EmuTime time)
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{
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	return peekIO(port, time);
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}
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byte MSXTurboRPCM::peekIO(uint16_t port, EmuTime time) const
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{
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	switch (port & 0x01) {
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	case 0:
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		// bit 0-1  15.700kHz counter
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		// bit 2-7  not used
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		return reference.getTicksTill(time) & 0x03;
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	case 1:
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		// bit 0   BUFF  0->D/A    TODO check this bit
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		//               1->A/D
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		// bit 1   MUTE  mute ALL sound  0->muted
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		// bit 2   FILT  filter  0->standard signal
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		//                       1->filtered signal
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		// bit 3   SEL   select 0->D/A
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		//                      1->Mic/Jack
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		// bit 4   SMPL  sample/hold  0->sample
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		//                            1->hold
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		// bit 5-6       not used
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		// bit 7   COMP  comparator result 0->greater
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		//                                 1->smaller
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		return (getComp(time) ? 0x80 : 0x00) | (status & 0x1F);
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	default:
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		UNREACHABLE;
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	}
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}
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void MSXTurboRPCM::writeIO(uint16_t port, byte value, EmuTime time)
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{
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	switch (port & 0x01) {
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	case 0:
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		// While playing: sample value
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		//       recording: compare value
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		// Resets counter
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		reference.advance(time);
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		DValue = value;
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		if (status & 0x02) { // not muted
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			assert(reference.getTime() <= time);
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			auto time2 = (status & 0x01) // BUFF
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			           ? reference.getFastAdd(1) // value only updates on the next clock
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			           : time;
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			assert(time <= time2);
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			dac.writeDAC(DValue, time2);
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		}
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		break;
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	case 1:
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		// bit 0   BUFF
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		// bit 1   MUTE  mute _all_ sound  0->no sound
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		// bit 2   FILT  filter  1->filter on
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		// bit 3   SEL   select  1->Mic/Jack  0->D/A
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		// bit 4   SMPL  sample/hold  1->hold
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		// bit 5-7  not used
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		byte change = status ^ value;
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		status = value;
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		if ((change & 0x01) && ((status & 0x01) == 0)) {
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			dac.writeDAC(DValue, time);
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		}
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		// TODO status & 0x08
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		if ((change & 0x10) && (status & 0x10)) {
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			hold = getSample(time);
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		}
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		hardwareMute(!(status & 0x02));
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		break;
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	}
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}
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byte MSXTurboRPCM::getSample(EmuTime time) const
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{
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	return (status & 0x04)
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		? narrow<byte>((connector.readSample(time) / 256) + 0x80)
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		: 0x80; // TODO check
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}
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bool MSXTurboRPCM::getComp(EmuTime time) const
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{
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	// TODO also when D/A ??
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	byte sample = (status & 0x10) ? hold : getSample(time);
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	return sample >= DValue;
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}
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void MSXTurboRPCM::hardwareMute(bool mute)
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{
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	if (mute == hwMute) return;
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	hwMute = mute;
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	if (hwMute) {
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		mixer.mute();
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	} else {
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		mixer.unmute();
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	}
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}
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template<typename Archive>
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void MSXTurboRPCM::serialize(Archive& ar, unsigned /*version*/)
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{
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	ar.template serializeBase<MSXDevice>(*this);
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	ar.serialize("audioConnector", connector,
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	             "reference",      reference,
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	             "status",         status,
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	             "DValue",         DValue,
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	             "hold",           hold,
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	             "DAC",            dac);
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	hardwareMute(!(status & 0x02));  // restore hwMute
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}
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INSTANTIATE_SERIALIZE_METHODS(MSXTurboRPCM);
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REGISTER_MSXDEVICE(MSXTurboRPCM, "TurboR-PCM");
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} // namespace openmsx