add method

Implementation

FpvType add(FloatingPointValue a, FloatingPointValue b,
    {FloatingPointRoundingMode roundingMode =
        FloatingPointRoundingMode.roundNearestEven}) {
  if (a.isNaN | b.isNaN) {
    return _propagateNaN(a, b);
  }
  if (a.isAnInfinity | b.isAnInfinity) {
    if (a.isAnInfinity && b.isAnInfinity && a.sign != b.sign) {
      return nan;
    }
    final infinity = a.isAnInfinity ? a : b;
    return _infinityOrLargestFinite(
        negative: infinity.sign.toBool(), roundingMode: roundingMode);
  }

  final aExact = _decodeFinite(a);
  final bExact = _decodeFinite(b);
  final commonExponent = min(aExact.exponent, bExact.exponent);
  final aSigned =
      (a.sign.toBool() ? -aExact.significand : aExact.significand) <<
          (aExact.exponent - commonExponent);
  final bSigned =
      (b.sign.toBool() ? -bExact.significand : bExact.significand) <<
          (bExact.exponent - commonExponent);
  final sum = aSigned + bSigned;
  final sameSignZeros =
      a.isAZero && b.isAZero && a.sign.toBool() == b.sign.toBool();
  final negative = sum.isNegative ||
      (sum == BigInt.zero &&
          (sameSignZeros
              ? a.sign.toBool()
              : roundingMode ==
                  FloatingPointRoundingMode.roundTowardsNegativeInfinity));

  return _quantize((significand: sum.abs(), exponent: commonExponent),
      negative: negative, roundingMode: roundingMode);
}