public static OpcodeEncoder AppendSIB(this OpcodeEncoder encoder, int scale, Register index, Register @base)
{
Debug.Assert(scale == 1 || scale == 2 || scale == 4 || scale == 8);
int svalue = 0;
if (scale == 1)
{
svalue = 0;
}
else if (scale == 2)
{
svalue = 1;
}
else if (scale == 4)
{
svalue = 2;
}
else if (scale == 8)
{
svalue = 3;
}
// scale
encoder.AppendBits(svalue, 2);
// index
if (index == null)
{
encoder.Append3Bits(Bits.b100);
}
else
{
encoder.AppendRegister(index);
}
// base
if (@base == null)
{
encoder.Append3Bits(Bits.b101);
}
else
{
encoder.AppendRegister(@base);
}
return(encoder);
}
public static OpcodeEncoder ModRegRMSIBDisplacement(this OpcodeEncoder encoder, Operand result, Operand op1, Operand op2)
{
if (op2.IsConstant)
{
encoder.AppendMod(true, op2); // 2:mod
encoder.AppendRegister(result.Register); // 3:register (destination)
encoder.AppendRM(op1); // 3:r/m (source)
encoder.AppendConditionalDisplacement(op2); // 8/32:displacement value
}
else
{
encoder.AppendMod(Bits.b00); // 2:mod
encoder.AppendRegister(result.Register); // 3:register (destination)
encoder.AppendRM(Bits.b100); // 3:r/m (source)
encoder.AppendSIB(1, op2.Register, op1.Register); // 8:sib (scale, index, base)
}
return(encoder);
}
