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System verilog, fork join_any

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surerdra

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Can any one please tell me,


Generally the "Fork join_any" is work like, if any one of the internal task can finished, it will non blocked the next statements.


My question is if i taken three tasks in "fork join_any", it has to wait for any two tasks can complete, then only it come out side of fork join_any


how it is ?
 

If you have tasks a, b, and c then if a takes 10, b task 2, and c takes 5 time units then the fork-join_any will exit when task b finishes (FYI a and c will still run to completion) and continue on to whatever follows the fork-join_any.

In other words the first block that finishes causes the join to occur, hence the name join_any. You can think of the Verilog fork-join as join_all

Here is an example:
Code Verilog - [expand]
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`timescale 1ps/1ps
module fork_join_any;
 
localparam ns = 1000;
 
bit clk;
always #(5*ns) clk = ~clk;
 
 
initial begin
 
  $display ("Starting fork-join_any test");
 
  fork
 
    begin
      repeat (10) @(posedge clk);
      $display ("Finished repeat (10)");   
    end
 
    begin
      repeat (4) @(posedge clk);
      $display ("Finished repeat (4)");   
    end
 
    begin
      repeat (7) @(posedge clk);
      $display ("Finished repeat (7)");   
    end
 
  join_any;
 
  $display ("Exiting fork-join_any");
 
  repeat (8) @(posedge clk);
 
  $display ("Finished fork-join_any test");
  $finish;
 
end
 
endmodule


Which has the following output:
Code: 
# Starting fork-join_any test
# Finished repeat (4)
# Exiting fork-join_any
# Finished repeat (7)
# Finished repeat (10)
# Finished fork-join_any test
# ** Note: $finish    : fork_join_any.sv(38)
#    Time: 115 ns  Iteration: 1  Instance: /fork_join_any
# End time: 08:03:23 on Jun 04,2019, Elapsed time: 0:00:06
# Errors: 0, Warnings: 0
 

You will need to use a semaphore
Code: 
[FONT=Courier New]semaphore s;
 
s = new(0);
fork
   begin : process1
    ...
    s.put(1);
   end
 begin : process2
    ...
    s.put(1);
   end
 begin : process3
    ...
    s.put(1);
 end
join_none
s.get(2);
disable fork; // kills remaining process
s = null; // removes semaphore (if you plan to reuse s)[/FONT]
 

the semaphore method is good

Thank you
 

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