code: private static void resplit(final double a[]) {
          final double c = a[0] + a[1];
          final double d = -(c - a[0] - a[1]);
  
          if (c < 8e298 && c > -8e298) { // MAGIC NUMBER
              double z = c * HEX_40000000;
              a[0] = (c + z) - z;
              a[1] = c - a[0] + d;
          } else {
              double z = c * 9.31322574615478515625E-10;
              a[0] = (c + z - c) * HEX_40000000;
              a[1] = c - a[0] + d;
          }
      }
docs: Recompute a split.
  @param a input/out array containing the split, changed
  on output