RE: [sv-bc] function task calling

For those members of the sv-bc that do not follow the sv-ec, this issue
is covered by 1336. You cannot call a task from a function except for
one special case: statements inside a fork/join_none may allow blocking
statements. That case requires that you look at the root of the call
stack, which mist be from an initial or always block.

I think it would be much simpler to change the terminology of a system
task to system function. (Although the work in making such a proposal
would be significant).


Dave


> -----Original Message-----
> From: owner-sv-bc@server.eda.org [mailto:owner-sv-bc@server.eda.org]
On
> Behalf Of Mark Hartoog
> Sent: Monday, September 10, 2007 10:12 AM
> To: Maidment, Matthew R; Brad Pierce; sv-bc@server.eda-stds.org
> Subject: RE: [sv-bc] function task calling
> 
> If the call is to a class virtual task, it is very complicate
> to check all possible implementations of the task.
> 
> > -----Original Message-----
> > From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On
> > Behalf Of Maidment, Matthew R
> > Sent: Saturday, September 08, 2007 11:25 AM
> > To: Brad Pierce; sv-bc@eda-stds.org
> > Subject: RE: [sv-bc] function task calling
> >
> > Does this imply traversing any potential call stack to
> > identify those tasks that have statements that are illegal in
> > a function?
> > I think this is impractical.
> >
> > --
> > Matt Maidment
> > mmaidmen@ichips.intel.com
> >
> >
> > >-----Original Message-----
> > >From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of
> > >Brad Pierce
> > >Sent: Saturday, September 08, 2007 11:21 AM
> > >To: sv-bc@eda-stds.org
> > >Subject: RE: [sv-bc] function task calling
> > >
> > >Rather than a blanket prohibition on task enables in function
> > >definitions, should the prohibition in 13.4.b be weakened to only
> > >disallow enables of tasks with statements that would be illegal in
a
> > >function?
> > >
> > >-- Brad
> > >
> > >-----Original Message-----
> > >From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of
> > >Steven Sharp
> > >Sent: Friday, September 07, 2007 11:28 AM
> > >To: sv-bc@eda-stds.org; shalom.bresticker@intel.com
> > >Subject: Re: [sv-bc] function task calling
> > >
> > >
> > >>Since functions are not allowed to call tasks, how can a function
> > >>contain a call to $display?
> > >
> > >Functions are not allowed to delay.  Functions are not
> > allowed to call
> > >tasks because a task could delay, indirectly delaying the function.
> > >
> > >System tasks cannot delay, so there is no problem with allowing
> > >functions to call them.  In SV terms, all system tasks are
> > essentially
> > >void functions.
> > >
> > >
> > >>What types of built-in system tasks are functions allowed to call?
> > >
> > >I am not aware of any built-in system task that can delay,
> > so I don't
> > >think there is any restriction.  I don't think there is a way for a
> > >user-defined system task to delay either, so I don't think
> > there is any
> > >need for a restriction there either.
> > >
> > >I think this restriction is a case where "task" means
> > "task", not "task
> > >or system task."
> > >
> > >Steven Sharp
> > >sharp@cadence.com
> > >
> > >
> > >--
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