RE: [sv-ac] RE: Call to vote: Due September 26 (resend with the correct Mantis number)

In my opinion, even adding the condition(s) of an immediate assertion to the
always_comb (or always_latch) sensistivity list is a BAD IDEA! It will
force engineers to go back to the old days of having to deal with simulation
and synthesis seeing very different things in the same block of code, and
will lead to mismatches in RTL simulation and synthesized hardware. It is
nasty, dangerous, and can risk expensive re-spins of a chip. Don't mess
with the rules of inferred sensivity!!!!

I would much rather see a rule in the standard that any type of assertion in
always_comb and always_latch does not affect the inferred sensitivity list
in any way. A cautionary note would be appropriate that if the immediate
assertion reads an expression that are not read elsewhere in the procedure,
the immediate assertion will not be evaluated when that expression changes
value.

Again, I am copying Cliff and Don, in case fellow real designers think I am
off base.

Stu
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Stuart Sutherland

Sutherland HDL, Inc.

stuart@sutherland-hdl.com

503-692-0898
www.sutherland-hdl.com

From: owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] On Behalf Of Samik
Sengupta
Sent: Friday, September 23, 2011 11:53 AM
To: Seligman, Erik; 'sv-ac@eda-stds.org'
Subject: [sv-ac] RE: Call to vote: Due September 26 (resend with the correct
Mantis number)

Hello Erik,

Thanks. I thought of that, although I did not check the mantis. I think it
is okay to say just "immediate", although IMO in this case verbosity may be
helpful. But I am fine either way.

Regards,
Samik

From: owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] On Behalf Of
Seligman, Erik
Sent: Friday, September 23, 2011 2:41 PM
To: 'sv-ac@eda-stds.org'
Subject: [sv-ac] RE: Call to vote: Due September 26 (resend with the correct
Mantis number)

Samik- wrt #2- remember that where we define deferred & final assertions, we
explicitly state that they are kinds of immediate assertions, so I think
we're covered as long as we just talk about immediate. (I remember writing
the defs that way explicitly to avoid later verbosity in situations like
this.)

From: owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] On Behalf Of Samik
Sengupta
Sent: Friday, September 23, 2011 11:39 AM
To: Korchemny, Dmitry; 'sv-ac@eda-stds.org'
Subject: [sv-ac] RE: Call to vote: Due September 26 (resend with the correct
Mantis number)

Mantis 3564 __X__ Yes ____ No

 <http://www.eda-stds.org/mantis/view.php?id=2093%20>
http://www.eda-stds.org/mantis/view.php?id=3564

 <http://www.eda-stds.org/mantis/file_download.php?file_id=5462&type=bug>
http://www.eda-stds.org/mantis/file_download.php?file_id=5462&type=bug

Friendly amendments:

1. Only the condition checked in the immediate assertion should be
added to the sensitivity list, i.e., nothing from action block should wake
up the always_comb.

2. I think we should be more specific and say "Expressions used in
immediate, final, and deferred assertions" - not only immediate.

I agree to Ed, Anupam, and Manisha that no expression from concurrent
assertion, including the clock, should go into the sensitivity list.

Thanks,
Samik

From: owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] On Behalf Of
Korchemny, Dmitry
Sent: Wednesday, September 21, 2011 12:12 PM
To: 'sv-ac@eda-stds.org'
Subject: [sv-ac] Call to vote: Due September 26 (resend with the correct
Mantis number)

-You have until 11:59 pm PDT, Monday, September 26, 2011 to respond

-An issue passes if there are zero NO votes and half of the eligible voters
respond with a YES vote.

-If you vote NO on any issue, your vote must be accompanied by a reason.

The issue will then be up for discussion during a future conference call.

As of the September 20, 2011 meeting, the eligible voters are

Ashok Bhatt

Eduard Cerny

Ben Cohen

Dana Fisman

Tapan Kapoor

Jacob Katz

Scott Little

Manisha Kulshrestha

Anupam Prabhakar

Erik Seligman

Samik Sengupta

Tom Thatcher

Mantis 3564 ____ Yes ____ No

http://www.eda-stds.org/mantis/view.php?id=3564
<http://www.eda-stds.org/mantis/view.php?id=2093%20>

http://www.eda-stds.org/mantis/file_download.php?file_id=5462
<http://www.eda-stds.org/mantis/file_download.php?file_id=5462&type=bug>
&type=bug

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