  static void  Ins_JROT( INS_ARG )
  {
    if ( args[1] != 0 )
    {
      CUR.IP      += (Int)(args[0]);
      CUR.step_ins = FALSE;

      /* See JMPR below */
      if(CUR.IP > CUR.codeSize ||
         (CUR.code[CUR.IP] != 0x2D && CUR.code[CUR.IP - 1] == 0x2D))
        CUR.IP -= 1;
    }
  }

The product reads data past the end, or before the beginning, of the intended buffer.