code: private static void splitAdd(final double a[], final double b[], final double ans[]) {
          ans[0] = a[0] + b[0];
          ans[1] = a[1] + b[1];
  
          resplit(ans);
      }
docs: Add two numbers in split form.
  @param a first term of addition
  @param b second term of addition
  @param ans placeholder where to put the result