private void Seek(int track, Type1CommandParams p)
{
_seekDestination = track;
_seekError = false;
// Schedule the first step of the heads
_system.Scheduler.Schedule(_commandBeginNsec, p, SeekCallback);
if (Log.Enabled)
{
Log.Write(LogComponent.IOPFloppy, "Seek to {0} initialized.", track);
}
}
private void SeekCallback(ulong skewNsec, object context)
{
if (_commandAbort)
{
//
// Abort the seek, perform no head steps and update no registers.
//
if (Log.Enabled)
{
Log.Write(LogComponent.IOPFloppy, "Seek aborted by ForceInterrupt.");
}
return;
}
// Set the FDC busy status.
_busy = true;
if (_fdcTrack == _seekDestination)
{
// We've arrived. Everyone out of the car.
// Clear the FDC Type I BUSY status
_busy = false;
//
// Do a verification. Since we're not emulating the floppy at a level
// low enough to verify header CRC and sector IDs, we assume those are OK
// and only compare our Physical track counter with the FDC's track counter.
//
Type1CommandParams p = (Type1CommandParams)context;
if (p.Verify && _drive.IsLoaded && (_fdcTrack != _drive.Track))
{
_seekError = true;
}
_headLoaded = p.HeadLoad;
RaiseInterrupt();
if (Log.Enabled)
{
Log.Write(LogComponent.IOPFloppy, "Seek to {0} (physical {1}) completed.", _seekDestination, _drive.Track);
}
}
else
{
// Not there yet, move one step in the right direction.
if (_fdcTrack < _seekDestination)
{
_fdcTrack++;
_drive.SeekTo(_drive.Track + 1);
}
else
{
_fdcTrack--;
_drive.SeekTo(_drive.Track - 1);
}
_system.Scheduler.Schedule(_stepTimeNsec, context, SeekCallback);
if (Log.Enabled)
{
Log.Write(LogComponent.IOPFloppy, "Seek step to {0} (physical {1})", _fdcTrack, _drive.Track);
}
}
}
private void Step(StepDirection direction, Type1CommandParams p)
{
if (direction != StepDirection.Last)
{
_stepDirection = direction;
}
_seekError = false;
// Schedule a step of the heads.
if (!_busy)
{
_system.Scheduler.Schedule(
_commandBeginNsec,
(timestampNsec, context) =>
{
if (_commandAbort)
{
//
// Abort the step, perform no head steps and update no registers.
//
if (Log.Enabled)
{
Log.Write(LogComponent.IOPFloppy, "Step aborted by ForceInterrupt.");
}
return;
}
if (!_busy)
{
// Raise the busy flag -- the command has been accepted.
_busy = true;
// Schedule the actual step
_system.Scheduler.Schedule(
_stepTimeNsec,
(ts, ctx) =>
{
switch (_stepDirection)
{
case StepDirection.Out: // one track closer to the outer edge
_drive.SeekTo(_drive.Track - 1);
if (p.Update)
{
_fdcTrack--;
}
break;
case StepDirection.In: // one track closer to the inner edge
_drive.SeekTo(_drive.Track + 1);
if (p.Update)
{
_fdcTrack++;
}
break;
default:
throw new InvalidOperationException("Unepxected step type.");
}
if (p.Verify && _drive.IsLoaded && (_fdcTrack != _drive.Track))
{
_seekError = true;
}
_headLoaded = p.HeadLoad;
RaiseInterrupt();
//
// Reset the busy flag, the step is complete.
//
_busy = false;
if (Log.Enabled)
{
Log.Write(LogComponent.IOPFloppy, "Step to {0} (physical {1}) completed.", _seekDestination, _drive.Track);
}
});
}
});
}
if (Log.Enabled)
{
Log.Write(LogComponent.IOPFloppy, "Step {0} initialized.", _stepDirection);
}
}
