RE: Attributes & Synthesis Pragmas


Subject: RE: Attributes & Synthesis Pragmas
From: J. Bhasker (jbhasker@cadence.com)
Date: Thu Oct 25 2001 - 06:53:12 PDT


Cliff:

Ok, you have the baton. Better have a proposal on the list of pragmas
by the next WG mtg to discuss.

- bhasker

--

J. Bhasker Cadence Design Systems 7535 Windsor Drive, Suite A200, Allentown, PA 18195 (610) 398-6312, (610) 530-7985(fax), jbhasker@cadence.com

-----Original Message----- From: owner-vlog-synth@eda.org [mailto:owner-vlog-synth@eda.org]On Behalf Of Clifford E. Cummings Sent: Wednesday, October 24, 2001 12:24 PM To: vlog-synth@eda.org Subject: Attributes & Synthesis Pragmas

Hi, All -

Paul makes a good point. I don't think we were only going to add the infinitely abusable full_case and parallel_case directives, but it is time to start brain-storming on others.

More attributes should be supported in the Synthesis Standard. I think I have been charged with making proposals in this area and I would appreciate it if you all would e-mail me a list of code in-line-pragmas that I could use as a starting point.

Some that come to mind for Synopsys include:

Synopsys infer_mux translate_off translate_on map_to_module

Ben Cohen has been submitting Synplicity pragmas dealing with memory inference.

If anyone knows of additional pragmas in use by various tools, could they please send them to me. I really should get working on my assignments so Bhasker doesn't think I'm a total loser (right now I think he would not user the word "total" ;-)

While we are on the subject, about the term "rtl_synthesis." I know we had this discussion over a year ago, but I still wonder why we have prefixed synthesis pragmas with "rtl_"

It seems like the biggest reason was so that it would match the VHDL synthesis document (a pretty lame reason). We also mentioned that "rtl_synthesis" recognized that there might someday be pragmas such as "beh_synthesis" (behavioral) or dp_synthesis (data path), etc. To me typing the extra characters "rtl_" in anticipation of other synthesis-type pragmas still seems silly. I still think a pragma of "synthesis" makes more sense as a general purpose synthesis (rtl, behavioral or data path) pragma and then later add rtl_synthesis or dp_synthesis pragmas that are specific to those tools.

Of course, with any pragma, a vendor could choose to ignore the pragma, issue a warning for the pragma or issue an error as they see fit. Perhaps a data path tool would only accept pragmas that have been added as dp_synthesis.

Comments?

Regards - Cliff

At 08:28 AM 10/24/01 -0700, you wrote: >I'm looking at the set of attributes defined for synthesis. So far, only >full_case and parallel_case are defined. There are lots of synthesis >pragmas supported by Synopsys and Cadence. Why do only two of them appear >as attributes? > >Paul

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