RE: [sv-ec] covergroup sample method

I don't think you would be allowed to call a covergroup sample method
from a sequence or property.  You could call a function that copies the
local variable and does the sample for you.

> -----Original Message-----
> From: owner-sv-ec@server.eda.org [mailto:owner-sv-ec@server.eda.org]
On
> Behalf Of Michael Burns
> Sent: Friday, October 12, 2007 4:39 PM
> To: Scott, David
> Cc: SV-EC
> Subject: Re: [sv-ec] covergroup sample method
> 
> 
> The problem is that we want to trigger coverage from within assertions
> using
> data in assertion local variables. I don't believe we are allowed to
> declare
> covergroups within assertions.
> 
> --Mike
> 
> David Scott wrote:
> > Mike,
> >
> > What's wrong with overriding using construction of specific
covergroup
> > instances?  For example:
> >
> >  covergroup cg (ref int x);
> >    coverpoint x;
> >  endgroup
> >  ...
> >  cg cv_myLocalInt = new(myLocalInt);
> >  ...
> >  cg cv_someOtherInt = new(someOtherInt);
> >
> > If you want to have the data for both of these merged together, the
> > "merge_instances" option that we just approved -- Mantis 1897 --
could
> > suffice.  The only difference from your proposal is that you have to
> > keep around multiple instances of the covergroup and use the
appropriate
> > one for your desired "override".
> >
> > -- David S
> >
> >
> > Michael Burns wrote:
> >>
> >> Hi folks,
> >>
> >> We've found a need in our methodology for an extension to the
> >> covergroup sample method. Basically, we'd like to be able to call
the
> >> sample method on a covergroup with overrides so that we can specify
> >> the data we want covered in the call, rather than just sampling
> >> whatever the covergroup is connected to. This allows us to gather
data
> >> in local variables and dump it into the covergroup to be covered.
This
> >> is useful in assertion-based methodologies and perhaps elsewhere.
> >>
> >> There is a detailed proposal in Freescale, but I don't have it in
hand
> >> yet. I wanted to bring this up now so we have a chance to consider
it
> >> in Monday's meeting if possible.
> >>
> >> The general idea is that if you had a covergroup like this:
> >>
> >>   covergroup cg (ref int x);
> >>     coverpoint x;
> >>   endgroup
> >>
> >> you could explicitly specify data to be sampled like so:
> >>
> >>   cg.sample(.x(myLocalInt));
> >>
> >> where the args to sample() are overriding the formal arguments of
the
> >> covergroup.
> >>
> >> Has this need been addressed in some other way I'm not aware of?
Does
> >> this seem like a feasible approach?
> >>
> >> --Mike
> >>
> >>
> >
> 
> 
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