问$urandom_range()生成的随机数是否是“周期随机”？

EN

//Test using a callback for error injection
    class Driver_cbs_drop extends Driver_cbs;
      
      virtual task pre_tx(ref Transaction tr, ref bit drop);
           // Randomly drop 1 out of every 100 transactions
           drop = ($urandom_range(0,99) == 0);
      endtask

    endclass

    program automatic test;
     Environment env;

     initial begin
       env = new();
       env.gen_cfg();
       env.build();

       begin // Create error injection callback
         Driver_cbs_drop dcd = new();
         env.drv.cbs.push_back(dcd); // Put into driverÕs Q
       end

       env.run();
       env.wrap_up();
     end
    endprogram

//Driver class with callbacks
    class Driver;
     Driver_cbs cbs[$];
     task run();
       bit drop;
       Transaction tr;

       forever begin
         drop = 0;
         agt2drv.get(tr);
         foreach (cbs[i]) cbs[i].pre_tx(tr, drop);
           if (!drop) continue;

           transmit(tr);

         foreach (cbs[i]) cbs[i].post_tx(tr);
       end
     endtask
    endclass

// Base callback class
    virtual class Driver_cbs; // Driver callbacks 
      virtual task pre_tx(ref Transaction tr, ref bit drop);
      // By default, callback does nothing
      endtask

      virtual task post_tx(ref Transaction tr);
      // By default, callback does nothing
      endtask
    endclass