[SV]SystemVerilog進程控制詳解及案例分析 ---wait fork/disable fork

    wait fork example ,In the below example：

module wait_fork;
  initial begin
    $display("-----------------------------------------------------------------");
    fork
      //Process-1
      begin
        $display($time,"\tProcess-1 Started");
        #5;
        $display($time,"\tProcess-1 Finished");
      end
      //Process-2
      begin
        $display($time,"\tProcess-2 Started");
        #20;
        $display($time,"\tProcess-2 Finished");
      end
    join_any
   $display("-----------------------------------------------------------------");
$finish; //ends the simulation
  end
endmodule

Simulator output: 

-----------------------------------------------------------------
0 Process-1 Started
0 Process-2 Started
5 Process-1 Finished
-----------------------------------------------------------------
 1.3、Example-2:  wait fork
In the below example, wait fork will wait for the completion of the second thread in the fork-join_any.
	for better understanding compare the result  of Example-1 and Example-2.
module wait_fork;
  initial begin
    $display("-----------------------------------------------------------------");
    fork
      //Process-1
      begin
        $display($time,"\tProcess-1 Started");
        #5;
        $display($time,"\tProcess-1 Finished");
      end
      //Process-2
      begin
        $display($time,"\tProcess-2 Started");
        #20;
        $display($time,"\tProcess-2 Finished");
      end
    join_any
    wait fork; //waiting for the completion of active fork threads
    $display("-----------------------------------------------------------------");
    $finish; //ends the simulation
  end
endmodule

Simulator output: 

-----------------------------------------------------------------
0 Process-1 Started
0 Process-2 Started
5 Process-1 Finished
20 Process-2 Finished
-----------------------------------------------------------------
  1.4、disable-fork
disable fork：导致进程杀死/终止从fork块启动的所有活动进程（causes the process to kill/terminate all the active processes started from fork blocks.）
	disable fork會殺死當前進程以及他的所有子進程
	disable fork example,In the below example：
	On execution of the disable fork, all the active process will get terminated. 
	Process-2 of fork-1,Process-1, and Process-2 of fork-2 will get terminated.
module disable_fork;
  initial begin
    $display("-----------------------------------------------------------------");
    //fork-1
    fork
      //Process-1
      begin
        $display($time,"\tProcess-1 of fork-1 Started");
        #5;
        $display($time,"\tProcess-1 of fork-1 Finished");
      end
      //Process-2
      begin
        $display($time,"\tProcess-2 of fork-1 Started");
        #20;
        $display($time,"\tProcess-2 of fork-1 Finished");
      end
    join_any
    //fork-2
    fork
      //Process-1
      begin
        $display($time,"\tProcess-1 of fork-2 Started");
        #5;
        $display($time,"\tProcess-1 of fork-2 Finished");
      end
      //Process-2
      begin
        $display($time,"\tProcess-2 of fork-2 Started");
        #20;
        $display($time,"\tProcess-2 of fork-2 Finished");
      end
    join_none   
    disable fork;
    $display("-----------------------------------------------------------------");
      $display($time,"\tAfter disable-fork");
    $display("-----------------------------------------------------------------");
  end
endmodule
Simulator output: 

-----------------------------------------------------------------
0 Process-1 of fork-1 Started
0 Process-2 of fork-1 Started
5 Process-1 of fork-1 Finished
-----------------------------------------------------------------
5 After disable-fork
-----------------------------------------------------------------
1.5、Example-3: disable-fork
 In the below example, sub_process started from process-2 will get terminated during the execution of disable fork.
module disable_fork;
  initial begin
    $display("-----------------------------------------------------------------");
    fork
      //Process-1
      begin
        $display($time,"\tProcess-1 of fork-1 Started");
        #5;
        $display($time,"\tProcess-1 of fork-1 Finished");
      end
      //Process-2
      begin
        sub_process();
      end
    join_any 
    disable fork;
    $display("-----------------------------------------------------------------");
    $display($time,"\tAfter disable-fork");
    $display("-----------------------------------------------------------------");
  end
  //Sub-Process
  task sub_process;
    $display($time,"\tSub-Process Started");
    #10;
    $display($time,"\tSub-Process Finished");
  endtask  
endmodule
Simulator output: 

-----------------------------------------------------------------
0 Process-1 of fork-1 Started
0 Sub-Process Started
5 Process-1 of fork-1 Finished
-----------------------------------------------------------------
5 After disable-fork
-----------------------------------------------------------------

                    
                                        gsithxy
                                                                                            
                    原创文章 230获赞 182访问量 6万+
                                            关注
                                                                私信
    
                展开阅读全文


作者：gsithxy
                    

 
                


                            案例分析
                            wait
                            fork