public Boolean ParseEntrypoints()
{
VerifySyntaxToken(TokenType.OpenBlock, "{");
while (true)
{
if (!Enumerator.HasToken())
{
throw new MicroassemblerParseException(Enumerator.Last, "Pair or } expected");
}
if (Enumerator.Current.TokenType == TokenType.CloseBlock)
{
Enumerator.Advance();
break;
}
if (Enumerator.Current.TokenType == TokenType.Pair)
{
Object[] pair = Enumerator.Current.Value as Object[];
Enumerator.Advance();
if (!(pair[1] is String))
{
throw new MicroassemblerParseException(Enumerator.Last, "Entrypoint pair value must be a symbol");
}
String symbol = (String)pair[1];
if (pair[0] is String)
{
String key = pair[0] as String;
switch (key.ToLower())
{
case "fetch":
Microprogram.FetchEntrypoint = symbol;
break;
case "interrupt":
Microprogram.InterruptEntrypoint = symbol;
break;
default: throw new MicroassemblerParseException(Enumerator.Last, $"Invalid entrypoint '{key}'");
}
}
else if (pair[0] is long)
{
int entryIndex = Convert.ToInt32(pair[0]);
if (Microprogram.InstructionEntrypoints.ContainsKey(entryIndex))
{
Console.WriteLine($"Warning: Duplicate entrypoint definition on line {Enumerator.Last.Line}, previous value overridden");
}
Microprogram.InstructionEntrypoints[entryIndex] = symbol;
}
else
{
throw new MicroassemblerParseException(Enumerator.Last, "Invalid Entrypoint");
}
if (Enumerator.HasNext() && Enumerator.Next.TokenType == TokenType.Pair)
{
VerifySyntaxToken(TokenType.ListDelimeter, ",");
}
if (Enumerator.HasNext() && Enumerator.Next.TokenType == TokenType.CloseBlock)
{
DiscardOptionalToken(TokenType.ListDelimeter, ",");
}
}
else
{
throw new MicroassemblerParseException(Enumerator.Current, "Pair expected");
}
}
return(true);
}
public Microprogram ParseProgram(String program)
{
Microprogram = new Microprogram();
Enumerator = Tokenizer.Tokenize(program);
if (Enumerator == null)
{
return(null);
}
while (Enumerator.HasToken())
{
Token token = Enumerator.Current;
Enumerator.Advance();
if (token.TokenType == TokenType.Word)
{
String keyword = (String)token.Value;
switch (keyword.ToLower())
{
case "config":
if (!ProcessConfigs())
{
return(null);
}
break;
case "const":
if (!ProcessConstant())
{
return(null);
}
break;
case "control":
if (!ProcessControlWordLabel())
{
return(null);
}
break;
case "sequence":
if (!ProcessSequence())
{
return(null);
}
break;
case "macro":
if (!ProcessMacro())
{
return(null);
}
break;
case "empty":
if (!ParseEmpty())
{
return(null);
}
break;
case "entrypoints":
if (!ParseEntrypoints())
{
return(null);
}
break;
default:
throw new MicroassemblerParseException(token, "Keyword expected");
}
}
else
{
throw new MicroassemblerParseException(token, "Keyword expected");
}
}
//Config sanity checks
if (Microprogram.MicroprogramLength <= 0)
{
throw new MicroassemblerParseException($"The microprogram length must be greater than zero");
}
if (Microprogram.OpcodeWidth <= 0)
{
throw new MicroassemblerParseException($"The opcode width must be greater than zero");
}
if (Microprogram.ControlWordWidth <= 0)
{
throw new MicroassemblerParseException($"The control word width must be greater than zero");
}
if (Microprogram.BankSelectorMask.Length <= 0)
{
throw new MicroassemblerParseException($"The bank selector width must be greater than zero");
}
if (Microprogram.BankSelectorMask.Length + 1 >= Microprogram.ControlWordWidth)
{
throw new MicroassemblerParseException($"Control word width of {Microprogram.ControlWordWidth} is invalid, as the bank selector has a width of {Microprogram.BankSelectorMask.Length}");
}
//Check control word label lengths
foreach (ControlWordLabel cw in Microprogram.ControlWordLabels.Values)
{
if (cw.Mask.Length <= 0)
{
throw new MicroassemblerParseException($"Control word label {cw.Name} must have a length that is geater than zero");
}
if (cw.Mask.Length + Microprogram.BankSelectorMask.Length > Microprogram.ControlWordWidth)
{
throw new MicroassemblerParseException($"Control word label {cw.Name} exceeds the maximum control word width of {Microprogram.ControlWordWidth - Microprogram.BankSelectorMask.Length}");
}
}
return(Microprogram);
}