/// <summary>
/// Converts a binary encoding, given as an StdLogicVector with respect to a floating point format to its
/// double representation.
/// </summary>
/// <param name="slv">The binary encoding</param>
/// <param name="fmt">The floating point format to be assumed</param>
/// <returns>The double representation</returns>
public static double ToFloat(this StdLogicVector slv, FloatFormat fmt)
{
if (slv.Size != fmt.TotalWidth)
{
throw new ArgumentException("Vector does not match specified floating point format");
}
slv = slv.ProperValue;
StdLogicVector mantissa = slv[fmt.FractionWidth - 1, 0];
StdLogicVector exponent = slv[fmt.FractionWidth + fmt.ExponentWidth - 1, fmt.FractionWidth];
StdLogic sign = slv[fmt.FractionWidth + fmt.ExponentWidth];
int exp = (int)exponent.ULongValue - fmt.Bias;
if (exponent.Equals(StdLogicVector._0s(fmt.ExponentWidth)))
{
// denormalized
long mant = mantissa.LongValue;
double result = (double)mant * Math.Pow(2.0, exp - 1);
return(result);
}
else if (exponent.Equals(StdLogicVector._1s(fmt.ExponentWidth)))
{
// Infinity / NaN
if (mantissa.Equals(StdLogicVector._0s(fmt.FractionWidth)))
{
// infinity
if (sign == '1')
{
return(double.NegativeInfinity);
}
else
{
return(double.PositiveInfinity);
}
}
else
{
// NaN
return(double.NaN);
}
}
else
{
// normalized
StdLogicVector number = StdLogicVector._1s(1).Concat(mantissa);
ulong mant = number.ULongValue;
double result = (double)mant * Math.Pow(2.0, exp - fmt.FractionWidth);
if (sign == '1')
{
result = -result;
}
return(result);
}
}