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