Subject: RE: new attribute (* synthesis, combinational *)
From: Stefen Boyd (stefen@boyd.com)
Date: Mon Dec 17 2001 - 15:17:57 PST
At 12:39 PM 12/17/2001 -0800, Raina, Rahul wrote:
>In the case of an unspecified else, what should the synthesis tool assume?
>e.g.
>
>always @*
> if (a == 1) x = 0;
>
>What should the synthesis tool assume about the a = 0 condition?
Hi Rahul,
The tool shouldn't assume anything. The logic specified
is not combinational, so the tool should produce an error.
In your example, since there is no attribute, I would
expect a latch (although it might do something else since
you specified a constant value).
The following should produce an error from any tool that
supports 1364.1:
(* synthesis, combinational *)
always @*
if (a)
q = d;
Regards,
Stefen
--------------------
Stefen Boyd Boyd Technology, Inc.
stefen@BoydTechInc.com (408)739-BOYD
www.BoydTechInc.com (408)739-1402 (fax)
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