BizHawk/ExternalCoreProjects/Virtu/DiskIIDrive.cs

131 lines
3.2 KiB
C#

using System;
namespace Jellyfish.Virtu
{
public sealed class DiskIIDrive
{
private readonly IDiskIIController _diskController;
private readonly int[][] _driveArmStepDelta = new int[PhaseCount][];
private bool _trackLoaded;
private bool _trackChanged;
private int _trackNumber;
private int _trackOffset;
private byte[] _trackData = new byte[Disk525.TrackSize];
private Disk525 _disk;
public DiskIIDrive(IDiskIIController diskController)
{
_diskController = diskController;
_driveArmStepDelta[0] = new[] { 0, 0, 1, 1, 0, 0, 1, 1, -1, -1, 0, 0, -1, -1, 0, 0 }; // phase 0
_driveArmStepDelta[1] = new[] { 0, -1, 0, -1, 1, 0, 1, 0, 0, -1, 0, -1, 1, 0, 1, 0 }; // phase 1
_driveArmStepDelta[2] = new[] { 0, 0, -1, -1, 0, 0, -1, -1, 1, 1, 0, 0, 1, 1, 0, 0 }; // phase 2
_driveArmStepDelta[3] = new[] { 0, 1, 0, 1, -1, 0, -1, 0, 0, 1, 0, 1, -1, 0, -1, 0 }; // phase 3
}
public void Sync(IComponentSerializer ser)
{
ser.Sync(nameof(_trackLoaded), ref _trackLoaded);
ser.Sync(nameof(_trackChanged), ref _trackChanged);
ser.Sync(nameof(_trackNumber), ref _trackNumber);
ser.Sync(nameof(_trackOffset), ref _trackOffset);
ser.Sync(nameof(_trackData), ref _trackData, false);
_disk?.Sync(ser);
}
// ReSharper disable once UnusedMember.Global
public void InsertDisk(string name, byte[] data, bool isWriteProtected)
{
FlushTrack();
_disk = Disk525.CreateDisk(name, data, isWriteProtected);
_trackLoaded = false;
}
private static int Clamp(int value, int min, int max)
{
return value < min ? min : value > max ? max : value;
}
internal void ApplyPhaseChange(int phaseState)
{
// step the drive head according to stepper magnet changes
int delta = _driveArmStepDelta[_trackNumber & 0x3][phaseState];
if (delta != 0)
{
int newTrackNumber = Clamp(_trackNumber + delta, 0, TrackNumberMax);
if (newTrackNumber != _trackNumber)
{
FlushTrack();
_trackNumber = newTrackNumber;
_trackOffset = 0;
_trackLoaded = false;
}
}
}
internal int Read()
{
if (LoadTrack())
{
int data = _trackData[_trackOffset++];
if (_trackOffset >= Disk525.TrackSize)
{
_trackOffset = 0;
}
_diskController.DriveLight = true;
return data;
}
return 0x80;
}
internal void Write(int data)
{
if (LoadTrack())
{
_trackChanged = true;
_trackData[_trackOffset++] = (byte)data;
if (_trackOffset >= Disk525.TrackSize)
{
_trackOffset = 0;
}
_diskController.DriveLight = true;
}
}
private bool LoadTrack()
{
if (!_trackLoaded && (_disk != null))
{
_disk.ReadTrack(_trackNumber, 0, _trackData);
_trackLoaded = true;
}
return _trackLoaded;
}
internal void FlushTrack()
{
if (_trackChanged)
{
_disk.WriteTrack(_trackNumber, 0, _trackData);
_trackChanged = false;
}
}
public bool IsWriteProtected => _disk?.IsWriteProtected ?? false;
private const int TrackNumberMax = 0x44;
private const int PhaseCount = 4;
public void DeltaUpdate(Action<byte[], byte[]> callback)
{
FlushTrack();
_disk.DeltaUpdate(callback);
}
}
}