Subject: Re: Inferring FPGA Hardware Features?
From: Michael McNamara (mac@verisity.com)
Date: Mon Jul 16 2001 - 08:22:38 PDT
VhdlCohen@aol.com writes:
> [1 <text/plain; ISO-8859-1 (quoted-printable)>]
> In a message dated 7/14/01 10:07:54 AM Pacific Daylight Time,
> kcoffman@sos.net writes:
> > <<One of the topics we touched on a few years ago was allowing
> > pragmas to make use of explicit FPGA features. One of the things
> > that drives me nuts is to know there is a hardware feature
> > available that I can't explicitly make use of. The best example
> > is clock enable, I'd love to be able to assign a signal to a flip
> > flop clock enable input. For example: (* signal1 attribute
> > clock_enable*). This group seems more open to allowing closer
> > ties to the underlying hardware, do you folks feel like
> > revisiting this topic? Other features include reset/preset/global
> > clock/sector clock, etc. I don't think the spec needs to define
> > all potential features, but should allow this mechanism and tie
> > down a few common ones.>>
>
> The concept is good, but I see issues with such pragmas or attributes.
...
>
> So the question really is: Do we want to sort out a "common" set of
> attributes that are useful for FPGA? This is not an easy task.
> Will it ever be complete? Vendors may also wish to provide
> specific tailorability into their tools (thru pragmas/attributes)
> to be competitive. Is it our job to define this set?
It is our job to come up with a system that will work, a framework for
the industry to use. We should define clear winners like parallel
case, and define a framework for the implementation of more.
Note that a classic problem is reuse: Probably a particular
case/endcase is once and for all parallel case; but a particular bit
of logic may not be always 'altera_implement_in_eab' in every
instatiation in a particular design, or even if so, then in a
subsequent design where the logic is reused in a larger structure.
--
//' Michael McNamara <mac@verisity.com>
_ // Sr VP Technology 650-934-6888
\ // Verisity Design 650-934-6801 FAX
\// <http://www.verisity.com> 408-930-6875 Cell
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