/// <summary>Decompose an IEEE754 double into the mantissa and exponent</summary>
public static void Decompose(this double x, out long mantissa, out int exponent, out int sign, bool raw = false)
{
// Normal numbers: (-1)^sign x 2^(e - 1023) x 1.fraction
// Subnormal numbers: (-1)^sign x 2^(1 - 1023) x 0.fraction
// Translate the double into sign, exponent, and mantissa.
var bits = unchecked ((ulong)BitConverter.DoubleToInt64Bits(x));
sign = bits.BitAt(63) != 0 ? -1 : +1;
exponent = (int)Bit.Bits_(bits, 63, 52);
mantissa = (long)Bit.Bits_(bits, 52, 0);
if (raw)
{
return;
}
// Normal numbers: add the '1' to the front of the mantissa.
if (exponent != 0)
{
mantissa |= 1L << 52;
}
else
{
exponent++;
}
// Bias the exponent
exponent -= 1023;
}