RE: [sv-ac] 1995 assertions in loops questions

 

 

________________________________

From: Seligman, Erik [mailto:erik.seligman@intel.com] 
Sent: Tuesday, December 04, 2007 10:26 AM
To: Lisa Piper
Cc: sv-ac@eda.org
Subject: RE: [sv-ac] 1995 assertions in loops questions

 

Those are good questions.

 

As for the statistics counters:  can you point me to the Manits ticket
or LRM section that describes these in detail?  A search for
'statistics' in Draft 4 only gives me 3 occurrences, none of which talks
about these in any detail.  If it's necessary to state something
explicit, my suggestion would be that we consider the total number of
attempts to be multipled by the loop iterations.  

Lisa Piper >>>] I think the information you are looking for is described
in 16.14.3.  Do a search for "attempt" in chapter 16. VPI for coverage
is in the chapter on code coverage. Specifically 39.5 VPI Coverage (I'm
not sure why the title of the chapter is code coverage instead of
coverage). 

 

Debug-wise, I think most reasonable tools will treat the assertion as a
set of assertions, one per loop iteration, for reporting purposes.  But
we don't need to specify this in the standard-- perhaps some vendors
will come up with other clever methods.  

 

I haven't thought a whole lot about VPI issues: I was assuming that
these would be handled like any other assertion in the VPI.  But I see
your point, that the iterators are now special objects with unique
status for the assertion.  Do you think we should modify the diagram in
36.43 to add a connection to a set of vpiAssertionIterator variables or
something?

[Lisa Piper >>>] No idea.  I am just learning VPI and don't know much
about how it is used in practice.  But if we want to view it as a single
assertion then I would think you'd want one counter. For a specific
failure message though, I would think you'd need to know which iterator
it was, which is why I thought the automatic error message that is
printed should have this information.

 

________________________________

From: owner-sv-ac@server.eda.org [mailto:owner-sv-ac@server.eda.org] On
Behalf Of Lisa Piper
Sent: Monday, December 03, 2007 7:33 PM
To: Seligman, Erik
Cc: sv-ac@server.eda.org
Subject: [sv-ac] 1995 assertions in loops questions

Hi Erik,

I finally took the time to review your proposal for assertions in for
loops. You state "It is still considered a single assertion, not a set
of assertions

for each iteration, so no loop index is used."  What happens to the
statistic counters?  If the loop executes 5 times, for example, is this
5 attempts of the same assertion?  So in this case, the number of
attempts is not equal to the number of clocks of the assertion?   Have
you given though to debug of these?  Should the message be required to
print the loop iterator value(s) for example?  While the user can create
a custom message, it might be nice if this were automated.  Have you
thought about VPI callbacks?  I would think that the user data could
supply the loop iterators, but I'm not an expert on VPI callbacks.

Lisa


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