/// <summary>
/// Converts a double value to its binary encoding, given a floating point format.
/// </summary>
/// <param name="value">The value to be encoded</param>
/// <param name="fmt">The floating point format to be assumed</param>
/// <returns>The binary encoding</returns>
public static StdLogicVector ToSLV(this double value, FloatFormat fmt)
{
StdLogicVector sign;
StdLogicVector exponent;
StdLogicVector mantissa;
if (double.IsInfinity(value))
{
sign = double.IsNegativeInfinity(value) ? (StdLogicVector)"1" : (StdLogicVector)"0";
exponent = StdLogicVector._1s(fmt.ExponentWidth);
mantissa = StdLogicVector._0s(fmt.FractionWidth);
}
else if (double.IsNaN(value))
{
sign = (StdLogicVector)"0";
exponent = StdLogicVector._1s(fmt.ExponentWidth);
mantissa = StdLogicVector._1s(fmt.FractionWidth);
}
else
{
sign = value < 0.0 ? (StdLogicVector)"1" : (StdLogicVector)"0";
double absvalue = Math.Abs(value);
int exp = 0;
while (absvalue >= 2.0)
{
absvalue *= 0.5;
exp++;
}
while (absvalue > 0.0 && absvalue < 1.0)
{
absvalue *= 2.0;
exp--;
}
if (absvalue == 0.0)
{
return(StdLogicVector._0s(fmt.TotalWidth));
}
else if (exp <= -fmt.Bias)
{
// denomalized
exponent = StdLogicVector._0s(fmt.ExponentWidth);
absvalue *= (double)(1L << (fmt.FractionWidth + 1));
long mant = (long)absvalue;
mantissa = StdLogicVector.FromLong(mant, fmt.FractionWidth);
}
else
{
absvalue -= 1.0;
absvalue *= (double)(1L << fmt.FractionWidth);
long mant = (long)absvalue;
mantissa = StdLogicVector.FromLong(mant, fmt.FractionWidth);
exponent = StdLogicVector.FromLong(exp + fmt.Bias, fmt.ExponentWidth);
}
}
return(sign.Concat(exponent.Concat(mantissa)));
}
/// <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);
}
}
/// <summary>
/// Converts a double value to its binary encoding, given a floating point format.
/// </summary>
/// <param name="value">The value to be encoded</param>
/// <param name="fmt">The floating point format to be assumed</param>
/// <returns>The binary encoding</returns>
public static StdLogicVector ToSLV(this double value, FloatFormat fmt)
{
StdLogicVector sign;
StdLogicVector exponent;
StdLogicVector mantissa;
if (double.IsInfinity(value))
{
sign = double.IsNegativeInfinity(value) ? (StdLogicVector)"1" : (StdLogicVector)"0";
exponent = StdLogicVector._1s(fmt.ExponentWidth);
mantissa = StdLogicVector._0s(fmt.FractionWidth);
}
else if (double.IsNaN(value))
{
sign = (StdLogicVector)"0";
exponent = StdLogicVector._1s(fmt.ExponentWidth);
mantissa = StdLogicVector._1s(fmt.FractionWidth);
}
else
{
sign = value < 0.0 ? (StdLogicVector)"1" : (StdLogicVector)"0";
double absvalue = Math.Abs(value);
int exp = 0;
while (absvalue >= 2.0)
{
absvalue *= 0.5;
exp++;
}
while (absvalue > 0.0 && absvalue < 1.0)
{
absvalue *= 2.0;
exp--;
}
if (absvalue == 0.0)
{
return StdLogicVector._0s(fmt.TotalWidth);
}
else if (exp <= -fmt.Bias)
{
// denomalized
exponent = StdLogicVector._0s(fmt.ExponentWidth);
absvalue *= (double)(1L << (fmt.FractionWidth+1));
long mant = (long)absvalue;
mantissa = StdLogicVector.FromLong(mant, fmt.FractionWidth);
}
else
{
absvalue -= 1.0;
absvalue *= (double)(1L << fmt.FractionWidth);
long mant = (long)absvalue;
mantissa = StdLogicVector.FromLong(mant, fmt.FractionWidth);
exponent = StdLogicVector.FromLong(exp + fmt.Bias, fmt.ExponentWidth);
}
}
return sign.Concat(exponent.Concat(mantissa));
}
public FloatFormat GetResultFormat()
{
FloatFormat fmt;
switch (ResultPrecision)
{
case EPrecision.Single:
fmt = FloatFormat.SingleFormat;
break;
case EPrecision.Double:
fmt = FloatFormat.DoubleFormat;
break;
case EPrecision.Custom:
fmt = new FloatFormat(ResultExponentWidth, ResultFractionWidth);
break;
default:
throw new NotImplementedException();
}
return fmt;
}
/// <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;
}
}
