LongAdder increment logic

LongAdder.java

    // @nitsanw : Comments are my own 
    public void add(long x) {
        Cell[] as; // local copy of volatile cells
        long b, v; // local copies for base/cell.value
        int m; // computed mask for doing cheap % 
        Cell a; // local copy of this thread's cell
        if ((as = cells) != null || // read cells, if we have cells we can ignore base 
            !casBase(b = base, b + x)) { // got no cells -> try and CAS base with new value
            boolean uncontended = true;
            if  (as == null || // we got no cells -> failed CAS on base
                (m = as.length - 1) < 0 || // got cells of length 0, don't think this can happen
                (a = as[getProbe() & m]) == null || // no cell exists for out thread hash
                !(uncontended = a.cas(v = a.value, v + x))) // the above are all false -> try and CAS cell.value with new value
                longAccumulate(x, null, uncontended); // all attempts failed, we need to dig deeper! 
        }
    }