public static DoubleComponents Decompose(this double d)
{
// See http://msdn.microsoft.com/en-us/library/aa691146(VS.71).aspx
// and Steve Hollasch's http://steve.hollasch.net/cgindex/coding/ieeefloat.html
// and PremK's http://blogs.msdn.com/b/premk/archive/2006/02/25/539198.aspx
var result = new DoubleComponents { Datum = d };
long bits = BitConverter.DoubleToInt64Bits(d);
bool fNegative = (bits < 0);
int exponent = (int)((bits >> 52) & 0x7ffL);
long mantissa = (bits & 0xfffffffffffffL);
result.Negative = fNegative;
result.RawExponentInt = exponent;
result.RawMantissaLong = mantissa;
if (exponent == 0x7ffL && mantissa != 0)
{
Contract.Assert(double.IsNaN(d));
// The number is an NaN. Client must interpret.
result.IsNaN = true;
return result;
}
// The first bit of the mathematical mantissaBits is always 1, and it is not
// represented in the stored mantissaBits bits. The following logic accounts for
// this and restores the mantissaBits to its mathematical value.
if (exponent == 0)
{
if (mantissa == 0)
{
// Returning either +0 or -0.
return result;
}
// Denormalized: A fool-proof detector for denormals is a zero exponentBits.
// Mantissae for denormals do not have an assumed leading 1-bit. Bump the
// exponentBits by one so that when we re-bias it by -1023, we have actually
// brought it back down by -1022, the way it should be. This increment merges
// the logic for normals and denormals.
exponent++;
}
else
{
// Normalized: radix point (the binary point) is after the first non-zero digit (bit).
// Or-in the *assumed* leading 1 bit to restore the mathematical mantissaBits.
mantissa = mantissa | (1L << 52);
}
// Re-bias the exponentBits by the IEEE 1023, which treats the mathematical mantissaBits
// as a pure fraction, minus another 52, because we treat the mathematical mantissaBits
// as a pure integer.
exponent -= 1075;
// Produce form with lowest possible whole-number mantissaBits.
while ((mantissa & 1) == 0)
{
mantissa >>= 1;
exponent++;
}
result.MathematicalBase2Exponent = exponent;
result.MathematicalBase2Mantissa = mantissa;
return result;
}
public static DoubleComponents Decompose(this double d)
{
// See http://msdn.microsoft.com/en-us/library/aa691146(VS.71).aspx
// and Steve Hollasch's http://steve.hollasch.net/cgindex/coding/ieeefloat.html
// and PremK's http://blogs.msdn.com/b/premk/archive/2006/02/25/539198.aspx
var result = new DoubleComponents {
Datum = d
};
long bits = BitConverter.DoubleToInt64Bits(d);
bool fNegative = (bits < 0);
int exponent = (int)((bits >> 52) & 0x7ffL);
long mantissa = (bits & 0xfffffffffffffL);
result.Negative = fNegative;
result.RawExponentInt = exponent;
result.RawMantissaLong = mantissa;
if (exponent == 0x7ffL && mantissa != 0)
{
Contract.Assert(double.IsNaN(d));
// The number is an NaN. Client must interpret.
result.IsNaN = true;
return(result);
}
// The first bit of the mathematical mantissaBits is always 1, and it is not
// represented in the stored mantissaBits bits. The following logic accounts for
// this and restores the mantissaBits to its mathematical value.
if (exponent == 0)
{
if (mantissa == 0)
{
// Returning either +0 or -0.
return(result);
}
// Denormalized: A fool-proof detector for denormals is a zero exponentBits.
// Mantissae for denormals do not have an assumed leading 1-bit. Bump the
// exponentBits by one so that when we re-bias it by -1023, we have actually
// brought it back down by -1022, the way it should be. This increment merges
// the logic for normals and denormals.
exponent++;
}
else
{
// Normalized: radix point (the binary point) is after the first non-zero digit (bit).
// Or-in the *assumed* leading 1 bit to restore the mathematical mantissaBits.
mantissa = mantissa | (1L << 52);
}
// Re-bias the exponentBits by the IEEE 1023, which treats the mathematical mantissaBits
// as a pure fraction, minus another 52, because we treat the mathematical mantissaBits
// as a pure integer.
exponent -= 1075;
// Produce form with lowest possible whole-number mantissaBits.
while ((mantissa & 1) == 0)
{
mantissa >>= 1;
exponent++;
}
result.MathematicalBase2Exponent = exponent;
result.MathematicalBase2Mantissa = mantissa;
return(result);
}
