code: private void ones(int n) {
          if (n > value.length)
              value = new int[n];
          Arrays.fill(value, -1);
          offset = 0;
          intLen = n;
      }
docs: Makes this number an {@code n}-int number all of whose bits are ones.
  Used by Burnikel-Ziegler division.
  @param n number of ints in the {@code value} array
  @return a number equal to {@code ((1<<(32*n)))-1}