code: function bnpCopyTo(r) {
    var this_array = this.array;
    var r_array    = r.array;
  
    for(var i = this.t-1; i >= 0; --i) r_array[i] = this_array[i];
    r.t = this.t;
    r.s = this.s;
  }
docs: (protected) copy this to r