RE: [sv-bc] Glitches in unique/priority case/if violations

Hi Brad,

I thought of this myself when I first saw Erik's proposal.
After I read the proposal, I thought the technique he
is proposing to deglitch those was not appropriate for
the unique/priority case/if glitch problem.  But, maybe
there are some things that could be done.

The fundamental issue with unique/priority case/if is the
lack of a clocking specification that would be used to
strobe the logic at appropriate times.  

In the immediate assertions situation, Erik is proposing to
replace the immediate assertions with concurrent assertions.
There are a few modifications to concurrent assertion semantics
to make them appropriate for replacing immediate assertions.
And by nature, concurrent assertions must be associated with
an implicit or explicit clocking event.

So, if we could oblige users to write their unique/priority
case/if constructs in code where clocking can be inferred,
perhaps the technology could work.

But what about cases where no clocking can be inferred?
Should those cases turn into errors?  Backwards compatibility
problems would then arise.  Though backwards incompatibility
with glitchy unique/priority detection could be argued to
be not such a bad thing... 

For the assertions proposal, I think this clocking situation
is easier.  In cases where no clocking can be inferred,
users will continue to use immediate assertions. They
are susceptible to glitches, but at least there are no
compatibility issues.

Regards,
Doug

-----Original Message-----
From: owner-sv-bc@server.eda.org [mailto:owner-sv-bc@server.eda.org] On
Behalf Of Brad Pierce
Sent: Monday, September 03, 2007 9:07 PM
To: sv-bc
Subject: [sv-bc] Glitches in unique/priority case/if violations

In http://www.eda-stds.org/sv-ac/hm/4668.html the SV-AC is proposing a
possible solution for the glitch issue in immediate assertions.

Is there some way that this proposal could be leveraged into a solution
for the glitch issue in unique/priority case/if violoations?

That is, could the violations of unique/priority be defined in terms of
implicit immediate assertions?

Erik's SV-AC proposal is at

  http://www.eda-stds.org/sv-ac/hm/att-4668/assertfinal070830es.pdf

-- Brad


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