record.py 文件源码

def _int_to_real(num):
    """
    Convert REAL8 from internal integer representation to Python reals.

    Zeroes:
        >>> print(_int_to_real(0x0))
        0.0
        >>> print(_int_to_real(0x8000000000000000)) # negative
        0.0
        >>> print(_int_to_real(0xff00000000000000)) # denormalized
        0.0

    Others:
        >>> print(_int_to_real(0x4110000000000000))
        1.0
        >>> print(_int_to_real(0xC120000000000000))
        -2.0
    """
    sgn = -1 if 0x8000000000000000 & num else 1
    mant = num & 0x00ffffffffffffff
    exp = (num >> 56) & 0x7f
    return math.ldexp(sgn * mant, 4 * (exp - 64) - 56)