public static Operand Parse(BytecodeReader reader, OpcodeType parentType)
{
uint token0 = reader.ReadUInt32();
if (token0 == 0)
return null;
var operand = new Operand(parentType);
var numComponents = token0.DecodeValue<OperandNumComponents>(0, 1);
switch (numComponents)
{
case OperandNumComponents.Zero:
{
operand.NumComponents = 0;
break;
}
case OperandNumComponents.One:
{
operand.NumComponents = 1;
break;
}
case OperandNumComponents.Four:
{
operand.NumComponents = 4;
operand.SelectionMode = token0.DecodeValue<Operand4ComponentSelectionMode>(2, 3);
switch (operand.SelectionMode)
{
case Operand4ComponentSelectionMode.Mask:
{
operand.ComponentMask = token0.DecodeValue<ComponentMask>(4, 7);
break;
}
case Operand4ComponentSelectionMode.Swizzle:
{
var swizzle = token0.DecodeValue(4, 11);
Func<uint, byte, Operand4ComponentName> swizzleDecoder = (s, i) =>
(Operand4ComponentName) ((s >> (i * 2)) & 3);
operand.Swizzles[0] = swizzleDecoder(swizzle, 0);
operand.Swizzles[1] = swizzleDecoder(swizzle, 1);
operand.Swizzles[2] = swizzleDecoder(swizzle, 2);
operand.Swizzles[3] = swizzleDecoder(swizzle, 3);
break;
}
case Operand4ComponentSelectionMode.Select1:
{
var swizzle = token0.DecodeValue<Operand4ComponentName>(4, 5);
operand.Swizzles[0] = operand.Swizzles[1] = operand.Swizzles[2] = operand.Swizzles[3] = swizzle;
break;
}
default:
{
throw new ParseException("Unrecognized selection method: " + operand.SelectionMode);
}
}
break;
}
case OperandNumComponents.N:
{
throw new ParseException("OperandNumComponents.N is not currently supported.");
}
}
operand.OperandType = token0.DecodeValue<OperandType>(12, 19);
operand.IndexDimension = token0.DecodeValue<OperandIndexDimension>(20, 21);
operand.IsExtended = token0.DecodeValue(31, 31) == 1;
if (operand.IsExtended)
ReadExtendedOperand(operand, reader);
Func<uint, byte, OperandIndexRepresentation> indexRepresentationDecoder = (t, i) =>
(OperandIndexRepresentation) t.DecodeValue((byte) (22 + (i * 3)), (byte) (22 + (i * 3) + 2));
for (byte i = 0; i < (byte) operand.IndexDimension; i++)
{
operand.Indices[i] = new OperandIndex();
var indexRepresentation = indexRepresentationDecoder(token0, i);
operand.Indices[i].Representation = indexRepresentation;
switch (indexRepresentation)
{
case OperandIndexRepresentation.Immediate32:
operand.Indices[i].Value = reader.ReadUInt32();
break;
case OperandIndexRepresentation.Immediate64:
operand.Indices[i].Value = reader.ReadUInt64();
goto default;
case OperandIndexRepresentation.Relative:
operand.Indices[i].Register = Parse(reader, parentType);
break;
case OperandIndexRepresentation.Immediate32PlusRelative:
operand.Indices[i].Value = reader.ReadUInt32();
goto case OperandIndexRepresentation.Relative;
case OperandIndexRepresentation.Immediate64PlusRelative:
operand.Indices[i].Value = reader.ReadUInt64();
goto case OperandIndexRepresentation.Relative;
default:
throw new ParseException("Unrecognised index representation: " + indexRepresentation);
}
}
var numberType = parentType.GetNumberType();
switch (operand.OperandType)
{
case OperandType.Immediate32:
{
var immediateValues = new Number4();
for (var i = 0; i < operand.NumComponents; i++)
immediateValues.SetNumber(i, Number.Parse(reader));
operand.ImmediateValues = immediateValues;
break;
}
case OperandType.Immediate64:
{
var immediateValues = new Number4();
for (var i = 0; i < operand.NumComponents; i++)
immediateValues.SetDouble(i, reader.ReadDouble());
operand.ImmediateValues = immediateValues;
break;
}
}
return operand;
}