YamahaSKW01.cc

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#include "YamahaSKW01.hh"
#include "DummyPrinterPortDevice.hh"
#include "CacheLine.hh"
#include "MSXException.hh"
#include "checked_cast.hh"
#include "serialize.hh"
 
// Implementation based on reverse-engineering of 'acet'/'uniabis', see:
//   https://www.msx.org/forum/msx-talk/hardware/trying-to-dump-yamaha-skw-01
//   https://github.com/uniabis/msxrawl/tree/main/dumpskw1
// The printer port is assumed to work the same as a standard MSX printer port.
// This seems to be OK, because when printing with the SKW-01 software and
// selecting the "HR-5X" printer and an emulated MSX Printer plugged in, sane
// output is produced.
// As the emulation is purely based on reverse engineering based on the built
// in software, there may be plenty of details wrong.
// Also note that the delay that is apparently present when writing the font
// address registers (other wise the READY bit wouldn't need to be read out) is
// not emulated. Because of that, the READY bit will always just be enabled.
 
namespace openmsx {
 
YamahaSKW01::YamahaSKW01(const DeviceConfig& config)
        : MSXDevice(config)
        , Connector(MSXDevice::getPluggingController(), MSXDevice::getName() + " printerport",
                    std::make_unique<DummyPrinterPortDevice>())
        , mainRom(MSXDevice::getName() + " main"     , "rom", config, "main")
        , fontRom(MSXDevice::getName() + " kanjifont", "rom", config, "kanjifont")
        , dataRom(MSXDevice::getName() + " data"     , "rom", config, "data")
        , sram(MSXDevice::getName() + " SRAM", 0x800, config)
{
        if (mainRom.size() != 32 * 1024) {
                throw MSXException("Main ROM must be exactly 32kB in size.");
        }
        if (fontRom.size() != 128 * 1024) {
                throw MSXException("Font ROM must be exactly 128kB in size.");
        }
        if (dataRom.size() != 32 * 1024) {
                throw MSXException("Data ROM must be exactly 32kB in size.");
        }
 
        reset(EmuTime::dummy());
}
 
void YamahaSKW01::reset(EmuTime::param time)
{
        fontAddress = {0, 0, 0, 0};
        dataAddress = 0;
 
        writeData(0, time);    // TODO check this, see MSXPrinterPort
        setStrobe(true, time); // TODO check this, see MSXPrinterPort
}
 
byte YamahaSKW01::readMem(word address, EmuTime::param time)
{
        return peekMem(address, time);
}
 
byte YamahaSKW01::peekMem(word address, EmuTime::param time) const
{
        if (address == one_of(0x7FC0, 0x7FC2, 0x7FC4, 0x7FC6)) {
                return 0x01; // for now, always READY to read
        } else if (address == one_of(0x7FC1, 0x7FC3, 0x7FC5, 0x7FC7)) {
                unsigned group = (address - 0x7FC1) / 2;
                unsigned base = 0x8000 * group;
                unsigned offset = fontAddress[group] & 0x7FFF;
                return fontRom[base + offset];
        } else if (address == 0x7FC8 || address == 0x7FC9) {
                return 0xFF;
        } else if (address == 0x7FCA || address == 0x7FCB) {
                if ((dataAddress & (1 << 15)) == 0) {
                        return dataRom[dataAddress & 0x7FFF];
                } else {
                        return sram[dataAddress & 0x7FF];
                }
        } else if (address == 0x7FCC) {
                // bit 1 = status / other bits always 1
                return getPluggedPrintDev().getStatus(time)
                       ? 0xFF : 0xFD;
        } else if (address < 0x8000) {
                return mainRom[address];
        } else {
                return 0xFF;
        }
}
 
void YamahaSKW01::writeMem(word address, byte value, EmuTime::param time)
{
        if (0x7FC0 <= address && address <= 0x7FC7) {
                unsigned group = (address - 0x7FC0) / 2;
                if ((address & 1) == 0) {
                        // LSB address
                        fontAddress[group] = (fontAddress[group] & 0xFF00) | uint16_t(value << 0);
                } else {
                        // MSB address
                        fontAddress[group] = (fontAddress[group] & 0x00FF) | uint16_t(value << 8);
                }
        } else if (address == 0x7FC8) {
                dataAddress = (dataAddress & 0xFF00) | uint16_t(value << 0);
        } else if (address == 0x7FC9) {
                dataAddress = (dataAddress & 0x00FF) | uint16_t(value << 8);
        } else if (address == 0x7FCA || address == 0x7FCB) {
                if ((dataAddress & (1 << 15)) != 0) {
                        sram.write(dataAddress & 0x7FF, value);
                }
        } else if (address == 0x7FCC) {
                setStrobe(value & 1, time);
        } else if (address == 0x7FCE) {
                writeData(value, time);
        }
}
 
const byte* YamahaSKW01::getReadCacheLine(word start) const
{
        if ((start & CacheLine::HIGH) == (0x7FC0 & CacheLine::HIGH)) {
                // 0x7FC0-0x7FCF memory mapped registers
                return nullptr; // not cacheable
        } else if (start < 0x8000) {
                return &mainRom[start];
        } else {
                return unmappedRead.data();
        }
}
 
byte* YamahaSKW01::getWriteCacheLine(word start) const
{
        if ((start & CacheLine::HIGH) == (0x7FC0 & CacheLine::HIGH)) {
                // 0x7FC0-0x7FCF memory mapped registers
                return nullptr; // not cacheable
        } else {
                return unmappedWrite.data();
        }
}
 
void YamahaSKW01::setStrobe(bool newStrobe, EmuTime::param time)
{
        if (newStrobe != strobe) {
                strobe = newStrobe;
                getPluggedPrintDev().setStrobe(strobe, time);
        }
}
 
void YamahaSKW01::writeData(uint8_t newData, EmuTime::param time)
{
        if (newData != data) {
                data = newData;
                getPluggedPrintDev().writeData(data, time);
        }
}
 
std::string_view YamahaSKW01::getDescription() const
{
        return "Yamaha SKW-01 printer port";
}
 
std::string_view YamahaSKW01::getClass() const
{
        return "Printer Port";
}
 
void YamahaSKW01::plug(Pluggable& dev, EmuTime::param time)
{
        Connector::plug(dev, time);
        getPluggedPrintDev().writeData(data, time);
        getPluggedPrintDev().setStrobe(strobe, time);
}
 
PrinterPortDevice& YamahaSKW01::getPluggedPrintDev() const
{
        return *checked_cast<PrinterPortDevice*>(&getPlugged());
}
 
template<typename Archive>
void YamahaSKW01::serialize(Archive& ar, unsigned /*version*/)
{
        ar.template serializeBase<MSXDevice>(*this);
        ar.serialize("fontAddress", fontAddress,
                     "dataAddress", dataAddress,
                     "SRAM"       , sram,
                     "strobe"     , strobe,
                     "data"       , data);
        // TODO force writing data to port?? (See MSXPrinterPort)
}
INSTANTIATE_SERIALIZE_METHODS(YamahaSKW01);
REGISTER_MSXDEVICE(YamahaSKW01, "YamahaSKW01");
 
} // namespace openmsx