SanyoFDC.cc

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#include "SanyoFDC.hh"
#include "CacheLine.hh"
#include "DriveMultiplexer.hh"
#include "WD2793.hh"
#include "serialize.hh"
 
// Note: although this implementation seems to work (e.g. for the Sanyo
// MFD-001), it has not been checked on real hardware how the FDC registers are
// mirrored across the slot, nor how the ROM is visible in the slot. Currently
// FDC registers are implemented to be not mirrored, and ROM is implemented to
// be visible in page 0 and 1.
 
namespace openmsx {
 
SanyoFDC::SanyoFDC(const DeviceConfig& config)
        : WD2793BasedFDC(config)
{
}
 
byte SanyoFDC::readMem(word address, EmuTime::param time)
{
        switch (address) {
        case 0x7FF8:
                return controller.getStatusReg(time);
        case 0x7FF9:
                return controller.getTrackReg(time);
        case 0x7FFA:
                return controller.getSectorReg(time);
        case 0x7FFB:
                return controller.getDataReg(time);
        case 0x7FFC:
        case 0x7FFD:
        case 0x7FFE:
        case 0x7FFF: {
                byte value = 0x3F;
                if (controller.getIRQ(time))  value |= 0x80;
                if (controller.getDTRQ(time)) value |= 0x40;
                return value;
        }
        default:
                return SanyoFDC::peekMem(address, time);
        }
}
 
byte SanyoFDC::peekMem(word address, EmuTime::param time) const
{
        switch (address) {
        case 0x7FF8:
                return controller.peekStatusReg(time);
                break;
        case 0x7FF9:
                return controller.peekTrackReg(time);
                break;
        case 0x7FFA:
                return controller.peekSectorReg(time);
                break;
        case 0x7FFB:
                return controller.peekDataReg(time);
                break;
        case 0x7FFC:
        case 0x7FFD:
        case 0x7FFE:
        case 0x7FFF: {
                // Drive control IRQ and DRQ lines are not connected to Z80 interrupt request
                // bit 7: intrq
                // bit 6: dtrq
                // other bits read 1
                byte value = 0x3F;
                if (controller.peekIRQ(time))  value |= 0x80;
                if (controller.peekDTRQ(time)) value |= 0x40;
                return value;
        }
        default:
                if (address < 0x8000) {
                        // ROM only visible in 0x0000-0x7FFF (not verified!)
                        return MSXFDC::peekMem(address, time);
                } else {
                        return 255;
                }
                break;
        }
}
 
const byte* SanyoFDC::getReadCacheLine(word start) const
{
        if ((start & CacheLine::HIGH) == (0x7FF8 & CacheLine::HIGH)) {
                // FDC at 0x7FF8-0x7FFC - mirroring behaviour unknown
                return nullptr;
        } else if (start < 0x8000) {
                // ROM at 0x0000-0x7FFF (this is a guess, not checked!)
                return MSXFDC::getReadCacheLine(start);
        } else {
                return unmappedRead.data();
        }
}
 
void SanyoFDC::writeMem(word address, byte value, EmuTime::param time)
{
        switch (address) {
        case 0x7FF8:
                controller.setCommandReg(value, time);
                break;
        case 0x7FF9:
                controller.setTrackReg(value, time);
                break;
        case 0x7FFA:
                controller.setSectorReg(value, time);
                break;
        case 0x7FFB:
                controller.setDataReg(value, time);
                break;
        case 0x7FFC:
        case 0x7FFD:
        case 0x7FFE:
        case 0x7FFF:
                // bit 0 -> select drive 0
                // bit 1 -> select drive 1
                // bit 2 -> side select
                // bit 3 -> motor on
                auto drive = [&] {
                        switch (value & 3) {
                                case 1:  return DriveMultiplexer::Drive::A;
                                case 2:  return DriveMultiplexer::Drive::B;
                                default: return DriveMultiplexer::Drive::NONE;
                        }
                }();
                multiplexer.selectDrive(drive, time);
                multiplexer.setSide((value & 0x04) != 0);
                multiplexer.setMotor((value & 0x08) != 0, time);
                break;
        }
}
 
byte* SanyoFDC::getWriteCacheLine(word address)
{
        if ((address & CacheLine::HIGH) == (0x7FF8 & CacheLine::HIGH)) {
                // FDC at 0x7FF8-0x7FFC - mirroring behaviour unknown
                return nullptr;
        } else {
                return unmappedWrite.data();
        }
}
 
 
template<typename Archive>
void SanyoFDC::serialize(Archive& ar, unsigned /*version*/)
{
        ar.template serializeBase<WD2793BasedFDC>(*this);
}
INSTANTIATE_SERIALIZE_METHODS(SanyoFDC);
REGISTER_MSXDEVICE(SanyoFDC, "SanyoFDC");
 
} // namespace openmsx