/// <summary>
/// Save data blocks
/// </summary>
/// <param name="vm">Export parameters</param>
/// <param name="blocksToSave">Collection of data blocks to save</param>
private static void SaveDataBlocks(ExportZ80ProgramViewModel vm, IEnumerable <byte[]> blocksToSave)
{
try
{
// --- Create directory
var dirName = Path.GetDirectoryName(vm.Filename);
if (dirName != null && !Directory.Exists(dirName))
{
Directory.CreateDirectory(dirName);
}
// --- Save data blocks
if (vm.Format == ExportFormat.Tzx)
{
using (var writer = new BinaryWriter(File.Create(vm.Filename)))
{
var header = new TzxHeader();
header.WriteTo(writer);
foreach (var block in blocksToSave)
{
var tzxBlock = new TzxStandardSpeedDataBlock
{
Data = block,
DataLength = (ushort)block.Length
};
tzxBlock.WriteTo(writer);
}
}
}
else
{
using (var writer = new BinaryWriter(File.Create(vm.Filename)))
{
foreach (var block in blocksToSave)
{
writer.Write((ushort)block.Length);
writer.Write(block);
}
}
}
}
catch (Exception ex)
{
VsxDialogs.Show($"An error has been raised while exporting a program: {ex.Message}",
"Errorr when exporting file");
}
}
/// <summary>
/// Playes back a standard speed data block entirely
/// </summary>
/// <param name="block">Data block to play back</param>
public static void CompleteBlock(this TzxStandardSpeedDataBlock block)
{
const int PILOT_PL = TapeDataBlockPlayer.PILOT_PL;
const int HEADER_PILOT_COUNT = TapeDataBlockPlayer.HEADER_PILOT_COUNT;
const int SYNC_1_PL = TapeDataBlockPlayer.SYNC_1_PL;
const int SYNC_2_PL = TapeDataBlockPlayer.SYNC_2_PL;
const long PILOT_END = PILOT_PL * HEADER_PILOT_COUNT;
const int TERM_SYNC = TapeDataBlockPlayer.TERM_SYNC;
const int PAUSE_MS = TapeDataBlockPlayer.PAUSE_MS;
var start = block.StartTact;
// --- Skip all pilot pulses + the first sync pulse
for (long pos = 0; pos < PILOT_END + SYNC_1_PL; pos += 50)
{
block.GetEarBit(start + pos);
}
// --- Skip the second sync pulse
for (var pos = PILOT_END + SYNC_1_PL + 50; pos < PILOT_END + SYNC_1_PL + SYNC_2_PL; pos += 50)
{
block.GetEarBit(start + pos);
}
// --- Play back the data
for (var i = 0; i < block.DataLength; i++)
{
block.ReadNextByte();
}
// --- Play back the terminating sync
var nextTact = block.LastTact;
for (var pos = nextTact; pos < nextTact + TERM_SYNC + 50; pos += 50)
{
block.GetEarBit(pos);
}
// --- Play back the pause
nextTact = block.LastTact;
for (var pos = nextTact; pos < nextTact + PAUSE_MS * block.PauseAfter + 100; pos += 50)
{
block.GetEarBit(pos);
}
}
/// <summary>
/// Save data blocks
/// </summary>
/// <param name="vm">Export parameters</param>
/// <param name="blocksToSave">Collection of data blocks to save</param>
private static void SaveDataBlocks(ExportZ80ProgramViewModel vm, IEnumerable <byte[]> blocksToSave)
{
// --- Create directory
var dirName = Path.GetDirectoryName(vm.Filename);
if (dirName != null && !Directory.Exists(dirName))
{
Directory.CreateDirectory(dirName);
}
// --- Save data blocks
if (vm.Format == ExportFormat.Tzx)
{
using (var writer = new BinaryWriter(File.Create(vm.Filename)))
{
var header = new TzxHeader();
header.WriteTo(writer);
foreach (var block in blocksToSave)
{
var tzxBlock = new TzxStandardSpeedDataBlock
{
Data = block,
DataLength = (ushort)block.Length
};
tzxBlock.WriteTo(writer);
}
}
}
else
{
using (var writer = new BinaryWriter(File.Create(vm.Filename)))
{
foreach (var block in blocksToSave)
{
writer.Write((ushort)block.Length);
writer.Write(block);
}
}
}
}
/// <summary>
/// Reads the data byte from the current playback position
/// </summary>
/// <param name="block">Block to play back</param>
/// <returns>Byte read</returns>
public static byte ReadNextByte(this TzxStandardSpeedDataBlock block)
{
const int BIT_0_PL = TapeDataBlockPlayer.BIT_0_PL;
const int BIT_1_PL = TapeDataBlockPlayer.BIT_1_PL;
const int STEP = 50;
var nextTact = block.LastTact + STEP;
byte bits = 0x00;
for (var i = 0; i < 8; i++)
{
// --- Wait for the high EAR bit
var samplesLow = 0;
while (!block.GetEarBit(nextTact))
{
samplesLow++;
nextTact += STEP;
}
// --- Wait for the low EAR bit
var samplesHigh = 0;
while (block.GetEarBit(nextTact) && samplesHigh < BIT_1_PL / STEP + 2)
{
samplesHigh++;
nextTact += STEP;
}
bits <<= 1;
if (samplesLow > (BIT_0_PL + BIT_1_PL) / 2 / STEP &&
samplesHigh > (BIT_0_PL + BIT_1_PL) / 2 / STEP)
{
bits++;
}
}
return(bits);
}
/// <summary>
/// Processes the the change of the MIC bit
/// </summary>
/// <param name="micBit">MIC bit to process</param>
public void ProcessMicBit(bool micBit)
{
if (_currentMode != TapeOperationMode.Save ||
_micBitState == micBit)
{
return;
}
var length = _cpu.Tacts - _lastMicBitActivityTact;
// --- Classify the pulse by its width
var pulse = MicPulseType.None;
if (length >= TapeDataBlockPlayer.BIT_0_PL - SAVE_PULSE_TOLERANCE &&
length <= TapeDataBlockPlayer.BIT_0_PL + SAVE_PULSE_TOLERANCE)
{
pulse = MicPulseType.Bit0;
}
else if (length >= TapeDataBlockPlayer.BIT_1_PL - SAVE_PULSE_TOLERANCE &&
length <= TapeDataBlockPlayer.BIT_1_PL + SAVE_PULSE_TOLERANCE)
{
pulse = MicPulseType.Bit1;
}
if (length >= TapeDataBlockPlayer.PILOT_PL - SAVE_PULSE_TOLERANCE &&
length <= TapeDataBlockPlayer.PILOT_PL + SAVE_PULSE_TOLERANCE)
{
pulse = MicPulseType.Pilot;
}
else if (length >= TapeDataBlockPlayer.SYNC_1_PL - SAVE_PULSE_TOLERANCE &&
length <= TapeDataBlockPlayer.SYNC_1_PL + SAVE_PULSE_TOLERANCE)
{
pulse = MicPulseType.Sync1;
}
else if (length >= TapeDataBlockPlayer.SYNC_2_PL - SAVE_PULSE_TOLERANCE &&
length <= TapeDataBlockPlayer.SYNC_2_PL + SAVE_PULSE_TOLERANCE)
{
pulse = MicPulseType.Sync2;
}
else if (length >= TapeDataBlockPlayer.TERM_SYNC - SAVE_PULSE_TOLERANCE &&
length <= TapeDataBlockPlayer.TERM_SYNC + SAVE_PULSE_TOLERANCE)
{
pulse = MicPulseType.TermSync;
}
else if (length < TapeDataBlockPlayer.SYNC_1_PL - SAVE_PULSE_TOLERANCE)
{
pulse = MicPulseType.TooShort;
}
else if (length > TapeDataBlockPlayer.PILOT_PL + 2 * SAVE_PULSE_TOLERANCE)
{
pulse = MicPulseType.TooLong;
}
_micBitState = micBit;
_lastMicBitActivityTact = _cpu.Tacts;
// --- Lets process the pulse according to the current SAVE phase and pulse width
var nextPhase = SavePhase.Error;
switch (_savePhase)
{
case SavePhase.None:
if (pulse == MicPulseType.TooShort || pulse == MicPulseType.TooLong)
{
nextPhase = SavePhase.None;
}
else if (pulse == MicPulseType.Pilot)
{
_pilotPulseCount = 1;
nextPhase = SavePhase.Pilot;
}
break;
case SavePhase.Pilot:
if (pulse == MicPulseType.Pilot)
{
_pilotPulseCount++;
nextPhase = SavePhase.Pilot;
}
else if (pulse == MicPulseType.Sync1 && _pilotPulseCount >= MIN_PILOT_PULSE_COUNT)
{
nextPhase = SavePhase.Sync1;
}
break;
case SavePhase.Sync1:
if (pulse == MicPulseType.Sync2)
{
nextPhase = SavePhase.Sync2;
}
break;
case SavePhase.Sync2:
if (pulse == MicPulseType.Bit0 || pulse == MicPulseType.Bit1)
{
// --- Next pulse starts data, prepare for receiving it
_prevDataPulse = pulse;
nextPhase = SavePhase.Data;
_bitOffset = 0;
_dataByte = 0;
_dataLength = 0;
_dataBuffer = new byte[DATA_BUFFER_LENGTH];
}
break;
case SavePhase.Data:
if (pulse == MicPulseType.Bit0 || pulse == MicPulseType.Bit1)
{
if (_prevDataPulse == MicPulseType.None)
{
// --- We are waiting for the second half of the bit pulse
_prevDataPulse = pulse;
nextPhase = SavePhase.Data;
}
else if (_prevDataPulse == pulse)
{
// --- We received a full valid bit pulse
nextPhase = SavePhase.Data;
_prevDataPulse = MicPulseType.None;
// --- Add this bit to the received data
_bitOffset++;
_dataByte = (byte)(_dataByte * 2 + (pulse == MicPulseType.Bit0 ? 0 : 1));
if (_bitOffset == 8)
{
// --- We received a full byte
_dataBuffer[_dataLength++] = _dataByte;
_dataByte = 0;
_bitOffset = 0;
}
}
}
else if (pulse == MicPulseType.TermSync)
{
// --- We received the terminating pulse, the datablock has been completed
nextPhase = SavePhase.None;
_dataBlockCount++;
// --- Create and save the data block
var dataBlock = new TzxStandardSpeedDataBlock
{
Data = _dataBuffer,
DataLength = (ushort)_dataLength
};
// --- If this is the first data block, extract the name from the header
if (_dataBlockCount == 1 && _dataLength == 0x13)
{
// --- It's a header!
var sb = new StringBuilder(16);
for (var i = 2; i <= 11; i++)
{
sb.Append((char)_dataBuffer[i]);
}
var name = sb.ToString().TrimEnd();
TapeProvider?.SetName(name);
}
TapeProvider?.SaveTapeBlock(dataBlock);
}
break;
}
_savePhase = nextPhase;
}
