RE: [sv-ec] Using a clocking block's pseudo-event

We could also do the same for coverage groups, and then I be able to write:

covergroup cg_a;  coverpoint a;  endgroup
covergroup cg_b @(cg_a.triggered)  coverpoint cg_b;  endgroup;


Of course this doesn't become very useful until you can also refer to
coverpoints inside cg_a as pseudo variables like:

covergroup cg_b @(cg_a.triggered)  aXb: cross cg_a.a, b;  endgroup;

Which allows me to extend the functionality of an existing coverage group
without having to completely rewrite it.

Ryan




                                                                           
             "Arturo Salz"                                                 
             <Arturo.Salz@syno                                             
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             Sent by:                  "Jonathan Bromley"                  
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                                       RE: [sv-ec] Using a clocking        
             01/11/2007 01:00          block's pseudo-event                
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Jonathan,

I'd be happy to submit your proposal. Thanks for offering to write it.

The syntax you propose (cb.event) may be problematic. Note that event is
already a keyword that designates a type. Anyhow, we probably could make
it work, but I don't think it's as important (or even needed) to spend
the time needed to do so.

             Arturo

-----Original Message-----
From: owner-sv-ec@eda.org [mailto:owner-sv-ec@eda.org] On Behalf Of
Jonathan Bromley
Sent: Thursday, January 11, 2007 10:51 AM
To: sv-ec@eda.org
Subject: RE: [sv-ec] Using a clocking block's pseudo-event

Arturo,

thanks for your response.

> I believe that extending the triggered method to a clocking block is a
> natural extension that makes a lot of sense. The only issue may be
> backward compatibility with clockvars named triggered, which
> is probably a low probability occurrence.

I don't have write access to Mantis; I'd be happy to write up
a proposal and submit it indirectly, though.

> However, I don't believe that allowing a clocking block to be assigned
> to an event handle is as coherent. After all a clocking block
> is not an event; it may support some of the same methods,
> but that doesn't change its type.

Syntactically you're right, of course, but it seems odd that
we can "virtualize" just about any other event using an event
handle, but we can't do that with the event tied to a
clocking.  If you're unhappy about
  event E = cb;
because of the obvious type discrepancy, how about we
permit the syntax
  cb.event
to gain explicit reference to the clocking's event?
That would also give us

  cb.event.triggered

with no risk of backward incompatibility.

I would be happy to see a semantic restriction
that events derived in this way should be "read-only",
so that they cannot be fired using -> or ->>.
On particularly sleepless nights I can imagine
meaningful uses for the procedural firing of a
clocking block, but the medication soon fixes that :-)
--
Jonathan Bromley, Consultant

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