code: private static int compareMagnitudeNormalized(long xs, int xscale, BigInteger ys, int yscale) {
          // assert "ys can't be represented as long"
          if (xs == 0)
              return -1;
          int sdiff = xscale - yscale;
          if (sdiff < 0) {
              if (longMultiplyPowerTen(xs, -sdiff) == INFLATED ) {
                  return bigMultiplyPowerTen(xs, -sdiff).compareMagnitude(ys);
              }
          }
          return -1;
      }
docs: Compare Normalize dividend & divisor so that both fall into [0.1, 0.999...]