Subject: Re: [sv-ac] Example showing reporting of variables in action block.
From: Arturo Salz (Arturo.Salz@synopsys.com)
Date: Tue Aug 26 2003 - 11:09:14 PDT
Adam,
Since the signals within the clocking domain (a,b,c) are referenced by the
property, they are implicitly declared as inputs to the clocking domain.
So there's no need to declare them individually. The two examples you
wrote below should be equivalent. You are, however, right that the LRM
does not describe this.
Arturo
----- Original Message -----
From: "Adam Krolnik" <krolnik@lsil.com>
To: "Jay Lawrence" <lawrence@cadence.com>
Cc: <sv-ac@eda.org>
Sent: Tuesday, August 26, 2003 10:53 AM
Subject: Re: [sv-ac] Example showing reporting of variables in action block.
Hi Jay;
>If assertions and the pass/fail statements are placed in a clocking
>domain then the sampling is controlled explicitly by the clocking domain
>sensitivity, and both the assertion and the pass/fail see the sampled
>values.
You know, I read the clocking domain section earlier today. There is no
description or example discussing how this works. There is *only* a reference
through the BNF in the section.
Is it this straightforward?
clocking @(posedge clk);
assert property
(a => b ##1 c)
else
$error("C (%0d) did not follow b after a.\n", c);
endclocking
Somehow, I figure the answer is no. From reading the section, I think it needs to
be:
clocking @(posedge clk);
default input #1step; // Specify get sampled values.
input a, b, c; // List all signals used below **1
assert property
(a => b ##1 c)
else
$error("C (%0d) did not follow b after a.\n", c);
endclocking
Is it required to list all signals used in assertions as inputs? This will be
a source of 'oh I forgot', or 'hmmm, I must've missed that signal.' It would
be safer if all referenced signals were included automatically...
Also, the BNF shows an optional clocking domain name. This is good as one
will probably have assertions/properties spread through the RTL code, not in
one place...
THanks.
Adam Krolnik
Verification Mgr.
LSI Logic Corp.
Plano TX. 75074
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