sc_fifo producer consumer semantics question

[Ankit10]

Hi,

I was experimenting with sc_fifo with the following producer-consumer code, my question is that why is the consumer not reading the values beyond 0? is it that the latest notification for sc_event at 1 has cancelled out the previous one at 0? how do I remedy this? do I have sc_fifo producer consumer dependent on clk edge only?

    sc_fifo_test(sc_module_name name😞sc_module(name),clk("clk",1,SC_SEC),f1(2),f2(2),f3(2){

    SC_THREAD(generator1);

    sensitive<<clk.posedge_event();

    dont_initialize();

    SC_THREAD(consumer1);

    sensitive<<f1.data_written_event();

    dont_initialize();

   };

 

void generator1()

    {

        int v = 0;

        while(true)

        {

            wait();

            f1.write(v);

            std::cout << sc_time_stamp() << ": generator1 writes " << v++ << "  @delta cycle "<<sc_delta_count()<<std::endl;

            wait(1,SC_SEC);

        }

    }

    void consumer1()

    {

        int v = -1;

        while(true)

        {

            wait();

            f1.read(v);

            std::cout << "\t"<<sc_time_stamp() << ": consumer1 reads " << v << "  @delta cycle "<<sc_delta_count()<<std::endl;

            wait(2,SC_SEC);

        }

    }

 

I get the following output

execution phase begins @ 0 s
1 s: generator1 writes 0  @delta cycle 4
2 s: generator1 writes 1  @delta cycle 8
        2 s: consumer1 reads 0  @delta cycle 9
3 s: generator1 writes 2  @delta cycle 12
execution phase ends @ 10 s
10 s: Cleanup: desctructor
 

[Ankit10]

Hi @Admin , please let me know if my theory holds water?

 

[maehne]

Your example code is not fully self-contained. Nevertheless, I wonder why you are waiting for 2 s at the end of each loop iteration in your consumer thread. The wait() call at the beginning should be sufficient.