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◆ main openmsx / src / sound / MSXPSG.cc
3.8 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#include "MSXPSG.hh"
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#include "CassettePort.hh"
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#include "JoystickPort.hh"
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#include "LedStatus.hh"
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#include "MSXMotherBoard.hh"
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#include "RenShaTurbo.hh"
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#include "serialize.hh"
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#include "StringOp.hh"
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#include "checked_cast.hh"
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#include "stl.hh"
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namespace openmsx {
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[[nodiscard]] static byte getKeyboardLayout(const MSXPSG& psg)
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{
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	// As many (mostly European) configs do not specify the layout
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	// in the PSG config, assume 50on for these cases.
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	auto value = psg.getDeviceConfig().getChildData("keyboardlayout", "50on");
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	StringOp::casecmp cmp; // case-insensitive
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	if (cmp(value, "50on")) {
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		return 0x00;
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	} else if (cmp(value, "jis")) {
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		return 0x40;
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	}
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	throw MSXException(
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		"Illegal keyboard layout configuration in '", psg.getName(),
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	        "' device configuration: '", value,
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		"', expected 'jis' or '50on'.");
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}
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// MSXDevice
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MSXPSG::MSXPSG(const DeviceConfig& config)
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	: MSXDevice(config)
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	, cassette(getMotherBoard().getCassettePort())
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	, renShaTurbo(getMotherBoard().getRenShaTurbo())
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	, ports(generate_array<2>([&](auto i) { return &getMotherBoard().getJoystickPort(unsigned(i)); }))
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	, keyLayout(getKeyboardLayout(*this))
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	, addressMask(config.getChildDataAsBool("mirrored_registers", false) ? 0x0f : 0xff)
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	, ay8910(getName(), *this, config, getCurrentTime())
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{
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	reset(getCurrentTime());
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}
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MSXPSG::~MSXPSG()
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{
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	powerDown(EmuTime::dummy());
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}
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void MSXPSG::reset(EmuTime time)
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{
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	registerLatch = 0;
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	ay8910.reset(time);
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}
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void MSXPSG::powerDown(EmuTime /*time*/)
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{
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	getLedStatus().setLed(LedStatus::KANA, false);
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}
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byte MSXPSG::readIO(uint16_t port, EmuTime time)
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{
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	switch (port & 0x03) {
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	case 2:
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		return ay8910.readRegister(registerLatch, time);
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	default:
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		// nothing for 0, 1 and 3
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		return 0xFF;
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	}
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}
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byte MSXPSG::peekIO(uint16_t /*port*/, EmuTime time) const
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{
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	return ay8910.peekRegister(registerLatch, time);
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}
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void MSXPSG::writeIO(uint16_t port, byte value, EmuTime time)
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{
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	switch (port & 0x03) {
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	case 0:
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		registerLatch = value & addressMask;
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		break;
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	case 1:
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		ay8910.writeRegister(registerLatch, value, time);
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		break;
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	}
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}
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// AY8910Periphery
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byte MSXPSG::readA(EmuTime time)
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{
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	byte joystick = ports[selectedPort]->read(time) |
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	                ((renShaTurbo.getSignal(time)) ? 0x10 : 0x00);
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#if 0
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	This breaks NinjaTap test programs.
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	Perhaps this behavior is different between MSX machines with a discrete
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	AY8910 chip versus machines with the PSG integrated in the MSX-engine?
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	// pin 6,7 input is ANDed with pin 6,7 output
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	byte pin67 = prev << (4 - 2 * selectedPort);
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	joystick &= (pin67| 0xCF);
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#endif
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	byte cassetteInput = cassette.cassetteIn(time) ? 0x80 : 0x00;
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	return joystick | keyLayout | cassetteInput;
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}
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void MSXPSG::writeB(byte value, EmuTime time)
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{
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	byte val0 =  (value & 0x03)       | ((value & 0x10) >> 2);
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	byte val1 = ((value & 0x0C) >> 2) | ((value & 0x20) >> 3);
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	ports[0]->write(val0, time);
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	ports[1]->write(val1, time);
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	selectedPort = (value & 0x40) >> 6;
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	if ((prev ^ value) & 0x80) {
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		getLedStatus().setLed(LedStatus::KANA, !(value & 0x80));
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	}
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	prev = value;
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}
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// version 1: initial version
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// version 2: joystickportA/B moved from here to MSXMotherBoard
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template<typename Archive>
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void MSXPSG::serialize(Archive& ar, unsigned version)
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{
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	ar.template serializeBase<MSXDevice>(*this);
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	ar.serialize("ay8910", ay8910);
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	if (ar.versionBelow(version, 2)) {
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		assert(Archive::IS_LOADER);
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		// in older versions there were always 2 real joystick ports
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		ar.serialize("joystickportA", *checked_cast<JoystickPort*>(ports[0]),
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		             "joystickportB", *checked_cast<JoystickPort*>(ports[1]));
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	}
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	ar.serialize("registerLatch", registerLatch);
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	byte portB = prev;
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	ar.serialize("portB", portB);
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	if constexpr (Archive::IS_LOADER) {
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		writeB(portB, getCurrentTime());
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	}
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	// selectedPort is derived from portB
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}
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INSTANTIATE_SERIALIZE_METHODS(MSXPSG);
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REGISTER_MSXDEVICE(MSXPSG, "PSG");
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} // namespace openmsx