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