RE: [sv-ac] Mantis 2476 ($onehot, etc, outside assertions)

http://www.eda-twiki.org/svdb/view.php?id=3054 asked for these to be allowed
in constraints and expanded so they do not break the solution space.

From: owner-sv-ac@eda.org [mailto:owner-sv-ac@eda.org] On Behalf Of
Srinivasan Venkataramanan
Sent: Tuesday, August 31, 2010 10:57 AM
To: Seligman, Erik
Cc: sv-ac@eda.org
Subject: Re: [sv-ac] Mantis 2476 ($onehot, etc, outside assertions)

Erik,

  IMHO we should allow #1 for sure. Also the following from #2 (if not
every thing, actually having everything would enable race debugging etc.
- imagine debugging a race and can use $sampled, would be very useful at
times): $countones, $past, $stable

Thanks

Srini

www.cvcblr.com

On Tue, Aug 31, 2010 at 9:14 PM, Seligman, Erik
<erik.seligman@intel.com> wrote:

Hi guys-I just added this note at
http://www.verilog.org/mantis/view.php?id=2476 . Perhaps we can discuss
in today's meeting.

We need to decide not just for the functions in the original
description, but for all the assertion system functions:
$onehot $onehot0 $isunknown $sampled $rose $fell $stable $changed $past
$countones $past_gclk $rose_gclk $fell_gclk $stable_gclk $changed_gclk
$future_gclk $rising_gclk $falling_gclk $steady_gclk $changing_gclk

I think the return types are clear in the final 2009 LRM, but the
question of their usage outside assertions is left ambiguous. For each
of these categories, do we want to enable outside assertions? My
instinct is just to enable category #1.
1. Simple booleans ($onehot $onehot0 $isunknown)
2. Sampled value functions ($sampled $rose $fell $stable $changed $past
$countones)
3. Global clocking past functions ($past_gclk $rose_gclk $fell_gclk
$stable_gclk $changed_gclk)
4. Global clocking future functions ($future_gclk $rising_gclk
$falling_gclk $steady_gclk $changing_gclk)

Interestingly, 20.13 seems to have an isolated BNF production
"assert_boolean_function" that is not referenced anywhere else in the
LRM, leaving it unclear where this can be used, though the implication
is that it's restricted to assertions. Should we fix this & Annex A to
properly integrate these functions into the grammar as well?

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