mbox.sv

module mbox();

  import types::*;

  mailbox exp_mb = new();
  mailbox act_mb = new();


  task stimulus();

    packet stim_pkt;
    packet falsePacket;

    for (int i = 0; i < 256; i++) begin
      stim_pkt.pid = i;
      falsePacket.pid = i;
      if(i == 250)
        falsePacket.pid = stim_pkt.pid + 1;

      exp_mb.put(stim_pkt);
      act_mb.put(falsePacket);

      $display("Sending pkt: %0d",i);
    end
  
  endtask

  task checker1();
    
    packet a,b;
    bit x;

    while(1) begin
      exp_mb.get(a);
      act_mb.get(b);

      //$display(a);
      //$display(b);

      x = fComp(a,b);

      //$display(x);

      if(!x)
        $display("Packets %0d and %0d not matching!!", a.pid, b.pid);

    end

  endtask

  function bit fComp(input packet s,y);

    if(s == y)
      return 1;
    else
      return 0;

  endfunction

  initial begin

    fork 
      stimulus();
      checker1();
    join_none

  end   

endmodule

types.sv

package types;

  typedef struct{
    int pid;
  }packet;

endpackage