ZXHawk: Overhaul datacorder and cassette loading code. This should now be more accurate and fixes a number of loading isues with particular games and loading schemes. There be desync dragons here!! Fixes #1446

src/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Hardware/Datacorder/DatacorderDevice.cs

@@ -122,14 +122,6 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 			MonitorFrame();
 		}
 
-		/// <summary>
-		/// No longer in use
-		/// </summary>
-		public void StartFrame()
-		{
-			//_buzzer.ProcessPulseValue(currentState);
-		}
-
 		/// <summary>
 		/// Starts the tape playing from the beginning of the current block
 		/// </summary>
@@ -466,27 +458,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 				cycles -= _waitEdge;
 
 				if (_position == 0 && _tapeIsPlaying)
-				{
+				{				
-					// start of block - take care of initial pulse level for PZX
-					switch (_dataBlocks[_currentDataBlockIndex].BlockDescription)
-					{
-						case BlockType.PULS:
-							// initial pulse level is always low
-							if (currentState)
-								FlipTapeState();
-							break;
-						case BlockType.DATA:
-							// initial pulse level is stored in block
-							if (currentState != _dataBlocks[_currentDataBlockIndex].InitialPulseLevel)
-								FlipTapeState();
-							break;
-						case BlockType.PAUS:
-							// initial pulse level is stored in block
-							if (currentState != _dataBlocks[_currentDataBlockIndex].InitialPulseLevel)
-								FlipTapeState();
-							break;
-					}
-
 					// notify about the current block
 					var bl = _dataBlocks[_currentDataBlockIndex];
 
@@ -595,7 +567,8 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 				_waitEdge = _dataBlocks[_currentDataBlockIndex].DataPeriods.Count > 0 ? _dataBlocks[_currentDataBlockIndex].DataPeriods[_position] : 0;
 
 				// flip the current state
-				FlipTapeState();
+				//FlipTapeState();
+				currentState = _dataBlocks[_currentDataBlockIndex].DataLevels[_position];
 			}
 
 			// update lastCycle and return currentstate

src/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Machine/SpectrumBase.cs

@@ -208,17 +208,17 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 			CPU.RegPC = 0;
 			
 			Spectrum.SetCpuRegister("SP", 0xFFFF);
-			Spectrum.SetCpuRegister("IY", 0xFFFF);
+			Spectrum.SetCpuRegister("IY", 0);
-			Spectrum.SetCpuRegister("IX", 0xFFFF);
+			Spectrum.SetCpuRegister("IX", 0);
 			Spectrum.SetCpuRegister("AF", 0xFFFF);
-			Spectrum.SetCpuRegister("BC", 0xFFFF);
+			Spectrum.SetCpuRegister("BC", 0);
-			Spectrum.SetCpuRegister("DE", 0xFFFF);
+			Spectrum.SetCpuRegister("DE", 0);
-			Spectrum.SetCpuRegister("HL", 0xFFFF);
+			Spectrum.SetCpuRegister("HL", 0);
 			Spectrum.SetCpuRegister("SP", 0xFFFF);
 			Spectrum.SetCpuRegister("Shadow AF", 0xFFFF);
-			Spectrum.SetCpuRegister("Shadow BC", 0xFFFF);
+			Spectrum.SetCpuRegister("Shadow BC", 0);
-			Spectrum.SetCpuRegister("Shadow DE", 0xFFFF);
+			Spectrum.SetCpuRegister("Shadow DE", 0);
-			Spectrum.SetCpuRegister("Shadow HL", 0xFFFF);
+			Spectrum.SetCpuRegister("Shadow HL", 0);
 
 			CPU.Regs[CPU.I] = 0;
 			CPU.Regs[CPU.R] = 0;
@@ -260,17 +260,16 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 			CPU.RegPC = 0;
 
 			Spectrum.SetCpuRegister("SP", 0xFFFF);
-			Spectrum.SetCpuRegister("IY", 0xFFFF);
+			//Spectrum.SetCpuRegister("IY", 0xFFFF);
-			Spectrum.SetCpuRegister("IX", 0xFFFF);
+			//Spectrum.SetCpuRegister("IX", 0xFFFF);
 			Spectrum.SetCpuRegister("AF", 0xFFFF);
-			Spectrum.SetCpuRegister("BC", 0xFFFF);
+			//Spectrum.SetCpuRegister("BC", 0xFFFF);
-			Spectrum.SetCpuRegister("DE", 0xFFFF);
+			//Spectrum.SetCpuRegister("DE", 0xFFFF);
-			Spectrum.SetCpuRegister("HL", 0xFFFF);
+			//Spectrum.SetCpuRegister("HL", 0xFFFF);
-			Spectrum.SetCpuRegister("SP", 0xFFFF);
 			Spectrum.SetCpuRegister("Shadow AF", 0xFFFF);
-			Spectrum.SetCpuRegister("Shadow BC", 0xFFFF);
+			//Spectrum.SetCpuRegister("Shadow BC", 0xFFFF);
-			Spectrum.SetCpuRegister("Shadow DE", 0xFFFF);
+			//Spectrum.SetCpuRegister("Shadow DE", 0xFFFF);
-			Spectrum.SetCpuRegister("Shadow HL", 0xFFFF);
+			//Spectrum.SetCpuRegister("Shadow HL", 0xFFFF);
 
 			CPU.Regs[CPU.I] = 0;
 			CPU.Regs[CPU.R] = 0;

src/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Media/MediaConverter.cs

@@ -145,15 +145,35 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 		/// Takes a PauseInMilliseconds value and returns the value in T-States
 		/// </summary>
 		public static int TranslatePause(int pauseInMS)
-		{
+		{			
-			// t-states per millisecond
+			var tspms = (double)(69888 * 50) / (double)1000;
-			var tspms = (69888 * 50) / 1000;
+			int res = (int)(pauseInMS * tspms);
-			// get value
-			int res = pauseInMS * tspms;
 
 			return res;
 		}
 
+		/// <summary>
+		/// Caluclate a data block XOR checksum
+		/// </summary>
+		/// <param name="buf"></param>
+		/// <param name="len"></param>
+		/// <returns></returns>
+		public static bool CheckChecksum(byte[] buf, int len)
+		{
+			byte c = 0;
+			for (int n = 0; n < len - 1; n++)
+			{
+				c ^= buf[n];
+			}
+
+			if (c == buf[len - 1])
+			{
+				return true;
+			}
+
+			return false;
+		}
+
 		/// <summary>
 		/// Decompresses a byte array that is Z-RLE compressed
 		/// </summary>

src/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Media/Tape/CSW/CswConverter.cs

@@ -197,12 +197,15 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 			t.BlockDescription = BlockType.CSW_Recording;
 			t.BlockID = 0x18;
 			t.DataPeriods = new List<int>();
+			t.DataLevels = new List<bool>();
 
 			if (flags.Bit(0))
 				t.InitialPulseLevel = true;
 			else
 				t.InitialPulseLevel = false;
 
+			bool currLevel = !t.InitialPulseLevel;
+
 			var rate = (69888 * 50) / sampleRate;
 
 			for (int i = 0; i < cswDataUncompressed.Length;)
@@ -215,10 +218,15 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 				}
 
 				t.DataPeriods.Add(length);
+
+				currLevel = !currLevel;
+				t.DataLevels.Add(currLevel);				
 			}
 
 			// add closing period
 			t.DataPeriods.Add((69888 * 50) / 10);
+			currLevel = !currLevel;
+			t.DataLevels.Add(currLevel);
 
 			// add to datacorder
 			_datacorder.DataBlocks.Add(t);

src/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Media/Tape/PZX/PzxConverter.cs

@@ -158,8 +158,10 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
 						t.BlockID = GetInt32(b, 0);
 						t.DataPeriods = new List<int>();
+						t.DataLevels = new List<bool>();
 
 						t.InitialPulseLevel = false;
+						bool pLevel = !t.InitialPulseLevel;
 
 						List<ushort[]> pulses = new List<ushort[]>();
 
@@ -197,6 +199,8 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 							for (int i = 0; i < x[0]; i++)
 							{
 								t.DataPeriods.Add(x[1]);
+								pLevel = !pLevel;
+								t.DataLevels.Add(pLevel);
 							}
 						}
 
@@ -220,6 +224,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
 						t.BlockID = GetInt32(b, 0);
 						t.DataPeriods = new List<int>();
+						t.DataLevels = new List<bool>();
 
 						List<ushort> s0 = new List<ushort>();
 						List<ushort> s1 = new List<ushort>();
@@ -235,6 +240,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 							initPulseLevel = (uint)((dCount & 0x80000000) == 0 ? 0 : 1);
 
 							t.InitialPulseLevel = initPulseLevel == 1;
+							bool bLevel = !t.InitialPulseLevel;
 
 							dCount = (int)(dCount & 0x7FFFFFFF);
 							pos += 4;
@@ -274,6 +280,8 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 										foreach (var pu in s1)
 										{
 											t.DataPeriods.Add((int)pu);
+											bLevel = !bLevel;
+											t.DataLevels.Add(bLevel);
 										}
 
 									}
@@ -282,13 +290,20 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 										foreach (var pu in s0)
 										{
 											t.DataPeriods.Add((int)pu);
+											bLevel = !bLevel;
+											t.DataLevels.Add(bLevel);
 										}
 
 									}
 								}
 							}
 							if (tail > 0)
+							{
 								t.DataPeriods.Add(tail);
+								bLevel = !bLevel;
+								t.DataLevels.Add(bLevel);
+							}
+								
 							dData.Clear();
 						}
 
@@ -320,12 +335,21 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 						var d = GetInt32(b, pos);
 						iniPulseLevel = ((d & 0x80000000) == 0 ? 0 : 1);
 						t.InitialPulseLevel = iniPulseLevel == 1;
+						bool paLevel = !t.InitialPulseLevel;
 						pCount = (d & 0x7FFFFFFF);
 
 						// convert to tape block
 						t.BlockDescription = BlockType.PAUS;
+						paLevel = !paLevel;
+						t.DataLevels.Add(paLevel);
 						t.DataPeriods.Add(0);
+
+						paLevel = !paLevel;
+						t.DataLevels.Add(paLevel);
 						t.DataPeriods.Add(pCount);
+
+						paLevel = !paLevel;
+						t.DataLevels.Add(paLevel);
 						t.DataPeriods.Add(0);
 
 						_datacorder.DataBlocks.Add(t);

src/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Media/Tape/TAP/TapConverter.cs

@@ -277,16 +277,25 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
 				// create a list to hold the data periods
 				List<int> dataPeriods = new List<int>();
+				List<bool> dataLevels = new List<bool>();
+
+				bool currLevel = false;
 
 				// generate pilot pulses
 				for (int i = 0; i < pilotLength; i++)
 				{
 					dataPeriods.Add(PILOT_PL);
+					currLevel = !currLevel;
+					dataLevels.Add(currLevel);
 				}
 
 				// add syncro pulses
 				dataPeriods.Add(SYNC_1_PL);
+				currLevel = !currLevel;
+				dataLevels.Add(currLevel);
 				dataPeriods.Add(SYNC_2_PL);
+				currLevel = !currLevel;
+				dataLevels.Add(currLevel);
 
 				int pos = 0;
 
@@ -296,13 +305,33 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 					for (byte b = 0x80; b != 0; b >>= 1)
 					{
 						if ((blockdata[i] & b) != 0)
+						{
 							dataPeriods.Add(BIT_1_PL);
+							currLevel = !currLevel;
+							dataLevels.Add(currLevel);
+						}
+							
 						else
+						{
 							dataPeriods.Add(BIT_0_PL);
+							currLevel = !currLevel;
+							dataLevels.Add(currLevel);
+						}
+							
 						if ((blockdata[i] & b) != 0)
+						{
 							dataPeriods.Add(BIT_1_PL);
+							currLevel = !currLevel;
+							dataLevels.Add(currLevel);
+						}
+							
 						else
+						{
 							dataPeriods.Add(BIT_0_PL);
+							currLevel = !currLevel;
+							dataLevels.Add(currLevel);
+						}
+							
 					}
 				}
 
@@ -310,13 +339,29 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 				for (byte c = 0x80; c != (byte)(0x80 >> BIT_COUNT_IN_LAST); c >>= 1)
 				{
 					if ((blockdata[pos] & c) != 0)
+					{
 						dataPeriods.Add(BIT_1_PL);
+						currLevel = !currLevel;
+						dataLevels.Add(currLevel);
+					}
 					else
+					{
 						dataPeriods.Add(BIT_0_PL);
+						currLevel = !currLevel;
+						dataLevels.Add(currLevel);
+					}
 					if ((blockdata[pos] & c) != 0)
+					{
 						dataPeriods.Add(BIT_1_PL);
+						currLevel = !currLevel;
+						dataLevels.Add(currLevel);
+					}
 					else
+					{
 						dataPeriods.Add(BIT_0_PL);
+						currLevel = !currLevel;
+						dataLevels.Add(currLevel);
+					}
 				}
 
 				// add block pause
@@ -325,14 +370,27 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
 				// default pause for tap files
 				tdb.PauseInMS = 1000;
+				tdb.PauseInTStates = TranslatePause(tdb.PauseInMS);
+
+				// small inversion
+				dataPeriods.Add(3476);
+				currLevel = !currLevel;
+				dataLevels.Add(currLevel);
+
+				// actual pause
+				dataPeriods.Add(tdb.PauseInTStates - 3476);
+				currLevel = !currLevel;
+				dataLevels.Add(currLevel);
 
 				// add to the tapedatablock object
 				tdb.DataPeriods = dataPeriods;
+				tdb.DataLevels = dataLevels;
 
 				// add the raw data
 				tdb.BlockData = blockdata;
 
 				// generate separate PAUS block
+				/*
 				TapeDataBlock tdbPause = new TapeDataBlock();
 				tdbPause.DataPeriods = new List<int>();
 				tdbPause.BlockDescription = BlockType.PAUSE_BLOCK;
@@ -341,10 +399,13 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 				//if (pauseInTStates > 0)
 				//tdbPause.DataPeriods.Add(pauseInTStates);
 				tdb.PauseInMS = 0;
+				tdb.PauseInTStates = pauseInTStates;
+				*/
 
 				// add block to the tape
 				_datacorder.DataBlocks.Add(tdb);
 
+				/*
 				// PAUS block if neccessary
 				if (pauseInTStates > 0)
 				{
@@ -366,6 +427,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
 					_datacorder.DataBlocks.Add(tdbPause);
 				}
+				*/
 			}
 		}
 	}

src/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Media/Tape/TapeDataBlock.cs

@@ -9,6 +9,12 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 	/// </summary>
 	public class TapeDataBlock
 	{
+		public TapeDataBlock()
+		{
+			DataPeriods = new List<int>();
+			DataLevels = new List<bool>();
+		}
+
 		/// <summary>
 		/// Either the TZX block ID, or -1 in the case of non-tzx blocks
 		/// </summary>
@@ -77,6 +83,13 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 		/// </summary>
 		public List<int> DataPeriods = new List<int>();
 
+		/// <summary>
+		/// List containing the pulse levels (in relation to the pulse timing values)
+		/// </summary>
+		public List<bool> DataLevels = new List<bool>();
+
+		public List<string> PulseDescription = new List<string>();
+
 		public bool InitialPulseLevel;
 
 		/// <summary>
@@ -91,7 +104,7 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 		}
 
 		/// <summary>
-		/// The defined post-block pause
+		/// The defined post-block pause in MS
 		/// </summary>
 		private int _pauseInMS;
 		public int PauseInMS
@@ -100,6 +113,15 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 			set => _pauseInMS = value;
 		}
 
+		/// <summary>
+		/// The defined post-block pause in T-States
+		/// </summary>
+		private int _pauseInTStates;
+		public int PauseInTStates
+		{
+			get { return _pauseInTStates; }
+			set { _pauseInTStates = value; }
+		}
 
 		/// <summary>
 		/// Returns the data periods as an array
@@ -226,6 +248,10 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 		Pulse_Length,
 		Pulse_Count,
 
+		TStatesPerSample,
+
+		Archive_Info,
+		Custom_Info,
 		Text_Description,
 		Title,
 		Publisher,

src/BizHawk.Emulation.Cores/Computers/SinclairSpectrum/Media/Tape/WAV/WavConverter.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using System.Linq;
 using System.Text;
 
 namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
@@ -85,7 +86,8 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 
 			WavStreamReader reader = new WavStreamReader(stream);
 
-			int rate = (69888 * 50) / reader.Header.sampleRate;
+			//int rate = (int)(((double)69888 * (double)50) / (double)reader.Header.sampleRate);
+			int rate = (int)((double)(3500000) / (double)reader.Header.sampleRate);
 			int smpCounter = 0;
 			int state = reader.ReadNext();
 
@@ -94,6 +96,9 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 			t.BlockDescription = BlockType.WAV_Recording;
 			t.BlockID = 0;
 			t.DataPeriods = new List<int>();
+			t.DataLevels = new List<bool>();
+
+			bool currLevel = false;
 
 			for (int i = 0; i < reader.Count; i++)
 			{
@@ -101,16 +106,33 @@ namespace BizHawk.Emulation.Cores.Computers.SinclairSpectrum
 				smpCounter++;
 				if ((state < 0 && sample < 0) || (state >= 0 && sample >= 0))
 					continue;
-				t.DataPeriods.Add(smpCounter * rate);
+				t.DataPeriods.Add((int)(((double)smpCounter * (double)rate) / (double)0.9838560885608856));
+				currLevel = !currLevel;
+				t.DataLevels.Add(currLevel);
 				smpCounter = 0;
 				state = sample;
 			}
 
 			// add closing period
 			t.DataPeriods.Add((69888 * 50) / 10);
+			currLevel = false;
+			t.DataLevels.Add(currLevel);
 
 			// add to datacorder
 			_datacorder.DataBlocks.Add(t);
+
+			StringBuilder export = new StringBuilder();
+			foreach (var b in _datacorder.DataBlocks)
+			{
+				for (int i = 0; i < b.DataPeriods.Count(); i++)
+				{
+					export.Append(b.DataPeriods[i].ToString());
+					export.Append("\t\t");
+					export.AppendLine(b.DataLevels[i].ToString());
+				}
+			}
+
+			string o = export.ToString();
 		}
 	}
 }