internal static void VisitSimCmd(VCDLexer lexer, IDToVarDef idToVariable, SimPass pass, BitAllocator bitAlloc)
{
ReadOnlyMemory <byte> declWordMem = lexer.NextWordAsMem();
ReadOnlySpan <byte> declWord = declWordMem.Span;
ReadOnlySpan <byte> endToken = new byte[] { (byte)'$', (byte)'e', (byte)'n', (byte)'d' };
ReadOnlySpan <byte> commentToken = new byte[] { (byte)'$', (byte)'c', (byte)'o', (byte)'m', (byte)'m', (byte)'e', (byte)'n', (byte)'t' };
ReadOnlySpan <byte> dumpAllToken = new byte[] { (byte)'$', (byte)'d', (byte)'u', (byte)'m', (byte)'p', (byte)'a', (byte)'l', (byte)'l' };
ReadOnlySpan <byte> dumpOffToken = new byte[] { (byte)'$', (byte)'d', (byte)'u', (byte)'m', (byte)'p', (byte)'o', (byte)'f', (byte)'f' };
ReadOnlySpan <byte> dumpOnToken = new byte[] { (byte)'$', (byte)'d', (byte)'u', (byte)'m', (byte)'p', (byte)'o', (byte)'n' };
ReadOnlySpan <byte> dumpVarsToken = new byte[] { (byte)'$', (byte)'d', (byte)'u', (byte)'m', (byte)'p', (byte)'v', (byte)'a', (byte)'r', (byte)'s' };
ReadOnlySpan <byte> hashtagToken = new byte[] { (byte)'#' };
//It may be the case that it's first discovered now that
// the end of the file has been reached.
if (declWord.Length == 0)
{
if (lexer.IsWordsRemaining())
{
throw new Exception("Invalid simulation command.");
}
return;
}
if (declWord.SequenceEqual(commentToken))
{
string text = lexer.NextUntil(endToken).ToCharString();
lexer.ExpectNextWord(endToken);
pass.SimCmd = new Comment(text);
}
else if (declWord.SequenceEqual(dumpAllToken))
{
pass.SimCmd = new DumpAll(VisitValueChangeStream(lexer, idToVariable, pass, bitAlloc));
}
else if (declWord.SequenceEqual(dumpOffToken))
{
pass.SimCmd = new DumpOff(VisitValueChangeStream(lexer, idToVariable, pass, bitAlloc));
}
else if (declWord.SequenceEqual(dumpOnToken))
{
pass.SimCmd = new DumpOn(VisitValueChangeStream(lexer, idToVariable, pass, bitAlloc));
}
else if (declWord.SequenceEqual(dumpVarsToken))
{
pass.SimCmd = new DumpVars(VisitValueChangeStream(lexer, idToVariable, pass, bitAlloc));
}
else if (declWord.StartsWith(hashtagToken))
{
pass.SimCmd = VisitSimTime(declWord);
}
else
{
VisitValueChange(lexer, declWordMem, idToVariable, pass, bitAlloc);
}
}
public VCDTimeline(VCD vcd)
{
this.TimeScale = vcd.Time;
var simCommands = vcd.GetSimulationCommands();
SimPass firstCmd = simCommands.First();
CircuitState segmentStartState;
if (firstCmd.SimCmd is DumpVars initDump)
{
segmentStartState = new CircuitState(initDump);
}
else
{
segmentStartState = new CircuitState(vcd.Variables.ToList());
simCommands = simCommands.Prepend(firstCmd);
}
CircuitState followState = segmentStartState.Copy();
ulong startTime = 0;
const int maxChangesPerSegment = 100_000;
List <BinaryVarValue> binChanges = new List <BinaryVarValue>(maxChangesPerSegment);
List <TimeStepChanges> stepChanges = new List <TimeStepChanges>();
int currTimeStepStart = 0;
int currTimeStepLength = 0;
foreach (var simCmd in simCommands)
{
if (simCmd.SimCmd is SimTime time)
{
if (currTimeStepLength > 0)
{
StateCount++;
TimeStepChanges timeStep = new TimeStepChanges(startTime, currTimeStepStart, currTimeStepLength);
currTimeStepStart += currTimeStepLength;
currTimeStepLength = 0;
stepChanges.Add(timeStep);
//If segment is full then store the segment and
//prepare for the next segment
if (binChanges.Count > maxChangesPerSegment)
{
TimeSpan tSpan = new TimeSpan(stepChanges.First().Time, time.Time);
SegmentChanges.Add(new TimeSegmentChanges(tSpan, segmentStartState, binChanges.ToArray(), stepChanges));
currTimeStepStart = 0;
currTimeStepLength = 0;
segmentStartState = followState;
followState = segmentStartState.Copy();
binChanges.Clear();
stepChanges = new List <TimeStepChanges>();
}
}
startTime = time.Time;
}
else if (simCmd.BinValue.HasValue)
{
followState.AddChange(simCmd.BinValue.Value);
binChanges.Add(simCmd.BinValue.Value);
currTimeStepLength++;
}
}
//Add last segment if it's not empty.
//Segment isn't added by above loop if the vcd file doesn't
//end with a simulation time command.
if (currTimeStepLength > 0)
{
stepChanges.Add(new TimeStepChanges(startTime, currTimeStepStart, currTimeStepLength));
}
if (stepChanges.Count > 0)
{
TimeSpan tSpan = new TimeSpan(stepChanges.First().Time, stepChanges.Last().Time + 1);
SegmentChanges.Add(new TimeSegmentChanges(tSpan, segmentStartState, binChanges.ToArray(), stepChanges));
}
this.TimeInterval = new TimeSpan(SegmentChanges.First().TimeInterval.StartInclusive, SegmentChanges.Last().TimeInterval.EndExclusive);
}
internal static void VisitScalarValueChange(ReadOnlyMemory <byte> text, IDToVarDef idToVariable, SimPass pass, BitAllocator bitAlloc)
{
UnsafeMemory <BitState> bits = bitAlloc.GetBits(1);
BitState bit = ToBitState(text.Span[0]);
var id = text.Slice(1);
bits.Span[0] = bit;
if (idToVariable.TryGetValue(id, out List <VarDef>?variable))
{
pass.BinValue = new BinaryVarValue(bits, variable, ((int)bit & 0b10) == 0);
}
else
{
throw new Exception($"Unknown variable identifier: {id}");
}
}
internal static void VisitRealVectorValueChange(VCDLexer lexer, ReadOnlySpan <byte> valueText, IDToVarDef idToVariable, SimPass pass, BitAllocator bitAlloc)
{
Span <char> chars = stackalloc char[valueText.Length];
valueText.CopyToCharArray(chars);
double value = double.Parse(chars, NumberStyles.Float, CultureInfo.InvariantCulture);
var id = lexer.NextWordAsMem();
if (idToVariable.TryGetValue(id, out List <VarDef>?variable))
{
pass.RealValue = new RealVarValue(value, variable);
}
else
{
throw new Exception($"Unknown variable identifier: {id}");
}
}
internal static void VisitBinaryVectorValueChange(VCDLexer lexer, ReadOnlySpan <byte> valueText, IDToVarDef idToVariable, SimPass pass, BitAllocator bitAlloc)
{
(UnsafeMemory <BitState> bits, bool isValidBinary) = ToBitStates(valueText, bitAlloc);
var id = lexer.NextWordAsMem();
if (idToVariable.TryGetValue(id, out List <VarDef>?variables))
{
pass.BinValue = new BinaryVarValue(bits, variables, isValidBinary);
}
else
{
throw new Exception($"Unknown variable identifier: {id}");
}
}
internal static void VisitValueChange(VCDLexer lexer, ReadOnlyMemory <byte> text, IDToVarDef idToVariable, SimPass pass, BitAllocator bitAlloc)
{
if (text.Length < 2)
{
throw new Exception($"Invalid value change: {text.ToString()}");
}
ReadOnlySpan <byte> textSpan = text.Span;
if (textSpan[0] == 'b' || textSpan[0] == 'B')
{
VisitBinaryVectorValueChange(lexer, textSpan.Slice(1), idToVariable, pass, bitAlloc);
}
else if (textSpan[0] == 'r' || textSpan[0] == 'R')
{
VisitRealVectorValueChange(lexer, textSpan.Slice(1), idToVariable, pass, bitAlloc);
}
else
{
VisitScalarValueChange(text, idToVariable, pass, bitAlloc);
}
}
internal static List <VarValue> VisitValueChangeStream(VCDLexer lexer, IDToVarDef idToVariable, SimPass pass, BitAllocator bitAlloc)
{
List <VarValue> changes = new List <VarValue>();
while (!lexer.IsEmpty())
{
ReadOnlyMemory <byte> text = lexer.NextWordAsMem();
ReadOnlySpan <byte> endToken = new byte[] { (byte)'$', (byte)'e', (byte)'n', (byte)'d' };
if (text.Span.SequenceEqual(endToken))
{
break;
}
VisitValueChange(lexer, text, idToVariable, pass, bitAlloc);
if (pass.BinValue.HasValue)
{
changes.Add(pass.BinValue);
}
else if (pass.RealValue.HasValue)
{
changes.Add(pass.RealValue);
}
else
{
throw new Exception("Expected to read a value change but found none.");
}
}
pass.Reset();
return(changes);
}
