return BigInteger.neg(this).roundToDouble(0, true, false); else
return neg(this).roundToDouble(0, true, false);
  public double doubleValue()  {    if (words == null)      return (double) ival;    if (ival <= 2)      return (double) longValue();    if (isNegative())      return BigInteger.neg(this).roundToDouble(0, true, false);    else      return roundToDouble(0, false, false);  }