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◆ main openmsx / src / fdc / AVTFDC.cc
2.6 KiB · C++ · last changed chore(): initial commit 1 month ago source blame history raw
e8555c89 Andy McCall 1 
#include "AVTFDC.hh"
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#include "DriveMultiplexer.hh"
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#include "WD2793.hh"
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#include "serialize.hh"
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namespace openmsx {
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AVTFDC::AVTFDC(DeviceConfig& config)
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	: WD2793BasedFDC(config)
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{
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}
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byte AVTFDC::readIO(uint16_t port, EmuTime time)
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{
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	switch (port & 0x07) {
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	case 0:
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		return controller.getStatusReg(time);
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	case 1:
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		return controller.getTrackReg(time);
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	case 2:
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		return controller.getSectorReg(time);
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	case 3:
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		return controller.getDataReg(time);
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	case 4: {
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		byte value = 0x7F;
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		if (controller.getIRQ(time))  value |=  0x80;
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		if (controller.getDTRQ(time)) value &= ~0x40;
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		return value;
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	}
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	default:
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		return 255;
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	}
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}
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byte AVTFDC::peekIO(uint16_t port, EmuTime time) const
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{
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	switch (port & 0x07) {
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	case 0:
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		return controller.peekStatusReg(time);
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	case 1:
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		return controller.peekTrackReg(time);
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	case 2:
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		return controller.peekSectorReg(time);
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	case 3:
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		return controller.peekDataReg(time);
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	case 4: {
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		byte value = 0x7F;
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		if (controller.peekIRQ(time))  value |=  0x80;
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		if (controller.peekDTRQ(time)) value &= ~0x40;
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		return value;
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	}
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	default:
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		return 255;
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	}
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}
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void AVTFDC::writeIO(uint16_t port, byte value, EmuTime time)
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{
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	switch (port & 0x07) {
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	case 0:
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		controller.setCommandReg(value, time);
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		break;
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	case 1:
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		controller.setTrackReg(value, time);
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		break;
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	case 2:
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		controller.setSectorReg(value, time);
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		break;
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	case 3:
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		controller.setDataReg(value, time);
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		break;
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	case 4: /* nothing only read... */
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		break;
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	case 5:
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		// From mohai
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		// bit 0:  drive select A (and motor on, as this is a WD1770,
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		// we use this as workaround)
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		// bit 1:  drive select B (and motor on, as this is a WD1770,
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		// we use this as workaround)
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		// bit 2:  side select
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		// bit 3:  density: 1=single 0=double (not supported by openMSX)
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		//
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		// Set correct drive
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		auto drive = [&] {
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			switch (value & 0x03) {
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			case 1:
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				return DriveMultiplexer::Drive::A;
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			case 2:
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				return DriveMultiplexer::Drive::B;
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			default:
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				// No drive selected or two drives at same time
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				// The motor is enabled for all drives at the same time, so
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				// in a real machine you must take care to do not select more
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				// than one drive at the same time (you could get data
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				// collision).
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				return DriveMultiplexer::Drive::NONE;
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			}
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		}();
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		multiplexer.selectDrive(drive, time);
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		multiplexer.setSide((value & 0x04) != 0);
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		multiplexer.setMotor(drive != DriveMultiplexer::Drive::NONE, time);
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		break;
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	}
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}
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template<typename Archive>
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void AVTFDC::serialize(Archive& ar, unsigned /*version*/)
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{
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	ar.template serializeBase<WD2793BasedFDC>(*this);
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}
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INSTANTIATE_SERIALIZE_METHODS(AVTFDC);
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REGISTER_MSXDEVICE(AVTFDC, "AVTFDC");
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} // namespace openmsx