Subject: Re: [sv-ac] $display in assertions
From: John Havlicek (john.havlicek@motorola.com)
Date: Fri Sep 12 2003 - 08:28:04 PDT
Surrendra:
Are you thinking of a general-purpose function?
It would be annoying to have to code a special function
for each $display I want to get.
Can you show an example of how to code the function and
how to write the function call in the assertion?
I don't understand your idea well enough to do this
myself.
Thanks,
John H.
> X-Sender: dudani@us04.synopsys.com
> Date: Fri, 12 Sep 2003 09:33:47 -0400
> From: Surrendra Dudani<Surrendra.Dudani@synopsys.com>
> Sender: owner-sv-ac@eda.org
> Precedence: bulk
>
> I think this can be accomplished by making a function call and hiding all
> the actions in the function such as $display. All the needed values for
> display can be passed to the function. Function calls are already allowed
> in the syntax. Will this work?
> Surrendra
> At 08:30 PM 9/11/2003 -0500, you wrote:
> >Folks:
> >
> >I have been thinking about Adam's request for reference
> >to local variables in the action block, and I don't see
> >a good solution.
> >
> >In CBV we allow various things like $display to be coded right
> >into the assertion. In CBV you can say
> >
> > if (req)
> > begin
> >
> > local my_req_tag[3:0] = req_tag;
> >
> > if +(0 to `TIME_LIMIT) : ~(resp & (resp_tag == my_req_tag))
> > begin
> > 0; // fail
> > $display("Error(time %d): no response within time_limit %d on
> > tag %h\n",
> > cbv_time, `TIME_LIMIT, my_req_tag);
> > end
> >
> > end
> >
> >Then we get the $display for every failing thread.
> >
> >Why can't we do this in SVA?
> >
> >If we approve the proposal on nesting and boolean connectives,
> >then this will be easy to achieve by simply allowing $display
> >as a property that is equivalent to "1'b1" in terms of assertion
> >pass/fail. Then the CBV above could be coded as
> >
> > my_req_tag[3:0];
> >
> > ...
> >
> > (req, my_req_tag = req_tag)
> > |->
> > (
> > ~(resp & (resp_tag == my_req_tag))[*`TIME_LIMIT]
> > |->
> > (
> > 1'b0 // fail
> > and
> > $display("Error(time %d): no response within time_limit %d on
> > tag %h\n",
> > ????, `TIME_LIMIT, my_req_tag);
> > )
> > );
> >
> >I have put ???? because I don't know how SV provides simulation time
> >(if it does at all), but this is a minor point.
> >
> >What do people think?
> >
> >Being able to do a "printf" style display of local variables is
> >absolutely essential for debugging and failure analysis. I do not
> >know how to solve this problem with the action block. Why don't we
> >just allow $display in the assertions?
> >
> >Anticipating comments,
> >
> >John Havlicek
>
>
>
> **********************************************
> Surrendra A. Dudani
> Synopsys, Inc.
> 377 Simarano Drive, Suite 300
> Marlboro, MA 01752
>
> Tel: 508-263-8072
> Fax: 508-263-8123
> email: Surrendra.Dudani@synopsys.com
> **********************************************
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