Merging events in SV

An event can be assigned to another event. Hence, waiting for either event will be unblocked by either event triggering.

Merging events example

There are two events e1 and e2.

In process_A, an event e2 variable is assigned with the e1 variable and an event e2 is triggered.

In process_B, the wait() construct is waiting for event e1 to be triggered.

Due to event merging, even though process_B is unblocked due to e2 event triggering even though it is waiting for event e1.

module event_example();
  event e1, e2;
  
  task process_A();
    e2 = e1;
    #10;
    ->e2;
    $display("@%0t: process_A: event e2 is triggered", $time);
  endtask
  
  task process_B();
    $display("@%0t: process_B: waiting for the event e1", $time);
    wait(e1.triggered);
    $display("@%0t: process_B: event e1 is received", $time);
  endtask

  initial begin
    fork
      process_A();
      process_B();
    join
  end
endmodule

Output:

@0: process_B: waiting for the event e1
@10: process_A: event e2 is triggered
@10: process_B: event e1 is received

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