Re: [sv-ac] Blocking actions in an attached task call

Hi Jonathan:

The intention was that the subroutine attached to a
sequence be executed as a separate thread.

The assertion evaluation does not wait on or receive 
data back from a subroutine call attached to a sequence.

Regards,

John H.

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> To sv-ac:
> 
> I have a difficulty concerning time-consuming (blocking)
> actions in task calls attached to a sequence.  The LRM
> clearly states that subroutines (task calls) attached
> to a sequence should execute in the Reactive region,
> but doesn't clearly describe what should happen if such
> a task call blocks for non-zero time.
> 
> I am fairly sure I've seen some discussion of this on the
> sv-ac list, but I can't find it.  If anyone can give me 
> a pointer to where I can locate any information I would 
> be most grateful.
> 
> Here's the problem.  Consider:
> 
>   task UserTask;
>     repeat(3) @(posedge clk);
>   endtask : UserTask
>   assert property (@(posedge clk) (a, UserTask) ##1 b);
> 
> Is it legal to include the blocking delay in UserTask?
> And if so, does UserTask execute as a separate thread,
> as if it had been spawned using fork...join_none?  If it
> is not a separate thread, what activity is blocked by it?
> 
> Please forgive me if I'm completely misunderstanding 
> the situation, and thanks in advance for your help.
> -- 
> Jonathan Bromley, Consultant