def _zero_mantissa(dval):
 bb = _double_as_bytes(dval)
 return (((bb[1] & 15) | reduce(operator.or_, bb[2:])) == 0)

def _zero_mantissa ( dval ) : bb = _double_as_bytes ( dval ) return ( ( ( bb [ 1 ] & 15 ) | reduce ( operator . or_ , bb [ 2 : ] ) ) == 0 )
determine whether the mantissa bits of the given double are all zero .