*
   * @param x the value to add
   */
  @Override
  public void add(long x) {
    Cell[] as;
    long b, v;
    int[] hc;
    Cell a;
    int n;
    if ((as = cells) != null || !casBase(b = base, b + x)) {
      boolean uncontended = true;
      if ((hc = threadHashCode.get()) == null
          || as == null
          || (n = as.length) < 1
          || (a = as[(n - 1) & hc[0]]) == null