MSXPSG.cc

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#include "MSXPSG.hh"
#include "LedStatus.hh"
#include "CassettePort.hh"
#include "MSXMotherBoard.hh"
#include "JoystickPort.hh"
#include "RenShaTurbo.hh"
#include "StringOp.hh"
#include "serialize.hh"
#include "checked_cast.hh"
#include "stl.hh"
 
namespace openmsx {
 
[[nodiscard]] static byte getKeyboardLayout(const MSXPSG& psg)
{
        // As many (mostly European) configs do not specify the layout
        // in the PSG config, assume 50on for these cases.
        auto value = psg.getDeviceConfig().getChildData("keyboardlayout", "50on");
        StringOp::casecmp cmp; // case-insensitive
        if (cmp(value, "50on")) {
                return 0x00;
        } else if (cmp(value, "jis")) {
                return 0x40;
        }
        throw MSXException(
                "Illegal keyboard layout configuration in '", psg.getName(),
                "' device configuration: '", value,
                "', expected 'jis' or '50on'.");
}
 
// MSXDevice
MSXPSG::MSXPSG(const DeviceConfig& config)
        : MSXDevice(config)
        , cassette(getMotherBoard().getCassettePort())
        , renShaTurbo(getMotherBoard().getRenShaTurbo())
        , ports(generate_array<2>([&](auto i) { return &getMotherBoard().getJoystickPort(unsigned(i)); }))
        , selectedPort(0)
        , prev(255)
        , keyLayout(getKeyboardLayout(*this))
        , addressMask(config.getChildDataAsBool("mirrored_registers", true) ? 0x0f : 0xff)
        , ay8910(getName(), *this, config, getCurrentTime())
{
        reset(getCurrentTime());
}
 
MSXPSG::~MSXPSG()
{
        powerDown(EmuTime::dummy());
}
 
void MSXPSG::reset(EmuTime::param time)
{
        registerLatch = 0;
        ay8910.reset(time);
}
 
void MSXPSG::powerDown(EmuTime::param /*time*/)
{
        getLedStatus().setLed(LedStatus::KANA, false);
}
 
byte MSXPSG::readIO(word /*port*/, EmuTime::param time)
{
        return ay8910.readRegister(registerLatch, time);
}
 
byte MSXPSG::peekIO(word /*port*/, EmuTime::param time) const
{
        return ay8910.peekRegister(registerLatch, time);
}
 
void MSXPSG::writeIO(word port, byte value, EmuTime::param time)
{
        switch (port & 0x03) {
        case 0:
                registerLatch = value & addressMask;
                break;
        case 1:
                ay8910.writeRegister(registerLatch, value, time);
                break;
        }
}
 
 
// AY8910Periphery
byte MSXPSG::readA(EmuTime::param time)
{
        byte joystick = ports[selectedPort]->read(time) |
                        ((renShaTurbo.getSignal(time)) ? 0x10 : 0x00);
 
#if 0
        This breaks NinjaTap test programs.
        Perhaps this behavior is different between MSX machines with a discrete
        AY8910 chip versus machines with the PSG integrated in the MSX-engine?
 
        // pin 6,7 input is ANDed with pin 6,7 output
        byte pin67 = prev << (4 - 2 * selectedPort);
        joystick &= (pin67| 0xCF);
#endif
 
        byte cassetteInput = cassette.cassetteIn(time) ? 0x80 : 0x00;
        return joystick | keyLayout | cassetteInput;
}
 
void MSXPSG::writeB(byte value, EmuTime::param time)
{
        byte val0 =  (value & 0x03)       | ((value & 0x10) >> 2);
        byte val1 = ((value & 0x0C) >> 2) | ((value & 0x20) >> 3);
        ports[0]->write(val0, time);
        ports[1]->write(val1, time);
        selectedPort = (value & 0x40) >> 6;
 
        if ((prev ^ value) & 0x80) {
                getLedStatus().setLed(LedStatus::KANA, !(value & 0x80));
        }
        prev = value;
}
 
// version 1: initial version
// version 2: joystickportA/B moved from here to MSXMotherBoard
template<typename Archive>
void MSXPSG::serialize(Archive& ar, unsigned version)
{
        ar.template serializeBase<MSXDevice>(*this);
        ar.serialize("ay8910", ay8910);
        if (ar.versionBelow(version, 2)) {
                assert(Archive::IS_LOADER);
                // in older versions there were always 2 real joystick ports
                ar.serialize("joystickportA", *checked_cast<JoystickPort*>(ports[0]),
                             "joystickportB", *checked_cast<JoystickPort*>(ports[1]));
        }
        ar.serialize("registerLatch", registerLatch);
        byte portB = prev;
        ar.serialize("portB", portB);
        if constexpr (Archive::IS_LOADER) {
                writeB(portB, getCurrentTime());
        }
        // selectedPort is derived from portB
}
INSTANTIATE_SERIALIZE_METHODS(MSXPSG);
REGISTER_MSXDEVICE(MSXPSG, "PSG");
 
} // namespace openmsx