From: Stuart Sutherland (stuart@sutherland-hdl.com)
Date: Wed Oct 03 2001 - 22:48:49 PDT
Precedence: bulk
Cliff,
I think you should try to slip this "typo correction" in. It corrects an
ambiguity and arguably a contradiction between sections 3.5 and 6.1.2. I
have a couple of suggestions on the wording of your proposal:
- Change "If an identifier appears as the target of a continuous assignment
statement..." to "If an identifier appears on the left-hand side of a
continuous assignment statement..."
- Change "...an implicit scalar wire declaration is assumed..." to "...an
implicit scalar net declaration of the default net type is assumed..."
Stu
At 02:05 PM 10/3/2001, Clifford E. Cummings wrote:
>Precedence: bulk
>
>Dear BTF -
>
>While submitting typo corrections to the IEEE, I would also like to try to
>submit one clarification paragraph in the list. The clarification
>paragraph has to do with implicit nets and the wording was submitted by
>Paul Graham of Cadence.
>
>PROPOSAL: Add the following indented paragraph to the end of section 3.5.
>Indenting to match the indenting of the two last paragraphs already in
>section 3.5:
>
>"If an identifier appears as the target of a continuous assignment
>statement, and that identifier has not been declared previously, then an
>implicit scalar wire declaration is assumed for that identifier."
>
>Please vote YES or NO on the above proposed addition to the end of section
>3.5 and e-mail your vote to me no later than Monday, October 15th, 2001.
>
>
>
>I know I said we could not add any clarification to the IEEE document, but
>I believe this is an exception for the following reasons:
>
>(1) Verilog-1995 required the target of a continuous assignment that did
>not drive a port to be explicitly declared.
>
>(2) Verilog-2001 removes this non-orthogonal restriction. As Mike
>MacNamara has noted, the BTF tried to remove the restriction by changing
>the first paragraph in section 6.1.2 to read as follows:
>
>"The continuous assignment statement shall place a continuous assignment
>on a net data type. The net may be explicitly declared, or may inherit an
>implicit declaration in accordance with the implicit declarations rules
>defined in 3.5."
>
>This was not clear enough as to our intent.
>
>(3) As has been noted in earlier threads, Don Mills & Stu Sutherland
>authored a paper about the Verilog-2001 Standard that incorrectly
>described the behavior of this change. This paper has been widely
>distributed (SNUG2001-Europe, SNUG2001-San Jose, SNUG2001-Dallas, others?)
>and used by many as a brief authoritative tutorial about Verilog-2001
>enhancements. Although the paper has been updated, corrected and placed on
>Don Mills' web site, the damage has been done, which is why I think we
>need to be more explicit in this description in the published
>IEEE1364-2001 Standard and not hope that we can verbally correct the
>confusion as the questions arise.
>
>We should be able to say: "This enhancement is described at the end of
>section 3.5 of the IEEE1364-2001 Standard."
>
>Please e-mail me your vote!
>
>Regards - Cliff Cummings
>Behavioral Task Force Chairperson
>
>//*****************************************************************//
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Stuart Sutherland Sutherland HDL Inc.
stuart@sutherland-hdl.com 22805 SW 92nd Place
phone: 503-692-0898 Tualatin, OR 97062
www.sutherland-hdl.com
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