docs: function unary_tritwise_op(tt, input, input_width) {
    if (tt < -13 || tt > 13) throw new Error('unary_tritwise_op('+tt+'): out of range iii-111');
    var bt_tt = pad(3, n2bts(tt), '0');
  
    var input_bt = pad(input_width, n2bts(input), '0');
  
    var output_bt = '';
  
    for (var i = 0; i < input_bt.length; ++i) {
      var in_trit = BT_DIGIT_TO_N[input_bt.charAt(i)];
      var out = bt_tt.charAt(in_trit + 1);
  
      output_bt += out;
    }
  
    var output = bts2n(output_bt);
  
    return output;
  }