public Assembler(ref byte[] bytes, AssemblerConfig config)
{
this.Config = config;
this.Bytes = bytes;
}
public Assembler(AssemblerConfig config)
{
this.Config = config;
}
/// <summary>
/// Determines addressing method of a line
/// </summary>
/// <param name="assembler"></param>
public void DetermineAddressingMethod(AssemblerConfig config)
{
if (this.OpCode == null)
{
throw new InvalidOperationException("Attempt to determine addressing method of non-statement");
}
if (this.RValue == null)
{
this.AddressingMethod = Assembly.AddressingMethod.implied;
return;
}
//will include branches, jmp, implied, accumulator (shown as implied
if (Assembly.OpcodeTable[OpCode.Value].Keys.Count == 1)
{
AddressingMethod = Assembly.OpcodeTable[OpCode.Value].Keys.First();
return;
}
//branches and jumps were already detected before this point
this.RValue.ParseValue(this.OpCode.Value);
var result = this.RValue.ComputedValue;
var choices =
RValue.LineEndingToOptions[this.RValue.ValueRight].Where(
choice => Assembly.OpcodeTable[this.OpCode.Value].Keys.Contains(choice)
).ToList();
if (choices.Count == 0)
{
throw new SyntaxErrorException("Illegal addressing method for opcode");
}
if (choices.Count == 1)
{
this.AddressingMethod = choices.First();
return;
}
if (result.Literal)
{
this.AddressingMethod = Assembly.AddressingMethod.immediate;
return;
}
choices.Remove(Assembly.AddressingMethod.immediate);
if (choices.Count == 0)
{
throw new SyntaxErrorException("Illegal addressing method for opcode");
}
if (choices.Count == 1)
{
this.AddressingMethod = choices.First();
return;
}
Assembly.AddressingMethod lo = choices.Where(choice => Assembly.AddressingMethodLength[choice] == 1).First();
Assembly.AddressingMethod hi = choices.Where(choice => Assembly.AddressingMethodLength[choice] == 2).First();
switch (config.OperandLength)
{
case AssemblerConfig.OperandLengthOption.Longest:
this.AddressingMethod = hi;
return;
case AssemblerConfig.OperandLengthOption.Smallest:
if (result.Result > byte.MaxValue)
{
this.AddressingMethod = hi;
return;
}
this.AddressingMethod = lo;
return;
case AssemblerConfig.OperandLengthOption.AsWritten:
//Only works in binary and hex because they're the ones where one extra digit is the point where it goes from one byte to two
if (result.Base == 2 || result.Base == 16)
{
//maximum characters before there are more characters than necessary to represent 256
int bumpLimit = result.Base == 2 ? 8 : 2;
if (result.ValueString.Length > bumpLimit)
{
this.AddressingMethod = hi;
return;
}
this.AddressingMethod = lo;
return;
}
if (result.Result > byte.MaxValue)
{
this.AddressingMethod = hi;
return;
}
this.AddressingMethod = lo;
return;
}
throw new SyntaxErrorException("Unable to determine addressing method");
}
