[sv-bc] FWD: from Dennis - keyword Config work-around

Please don't use 'Config' as the first word of your subject
or use 'Config' as the first word of the subject after 'RE:' 

Here is a note from Dennis:


>Subject: RE: [sv-bc] Re: Config-keyword work-around - was: 
>potential command line option
>From: "Brophy, Dennis" <dennisb@model.com>
>To: "Steven Sharp" <sharp@cadence.com>, <btf@boyd.com>, <etf@boyd.com>,
>        <sv-bc@server.eda.org>, <sv-ec@server.eda.org>,
>        <cliffc@sunburst-design.com>
>
>Steven,
>
>  It's too late to re-write 1364-2001.  I really think the topic of
>config was put to bed with the approval of the specification by the
>IEEE-SA Board in March 2001.  My reading does not conclude the 
>intent of config is in doubt.  The LRM is rather explicit: "As
evidenced by the
>config-endconfig syntax, the config is a design element, similar to a
>module, which exists in the Verilog namespace."  This makes it clear
>that it is intended for the Verilog same stream which accepts the
module
>descriptions and not intended to be separate.  It is clearly contain
>within.
>
>  You argument about A 1.1, A 1.2, etc. also does not hold water.  The
>BNF references "source text" not "source text files."  This lends
>further evidence that the file container notion was not part of the BNF
>as you postulate.
>
>  For those of us who have been supporting 1364-2001 in this fashion,
we
>know this has had an impact on consumer designs and libraries.
>1364-2001 consumers have learned to accommodate the evolution of
>Verilog.
>
>  I find the argument that config is a serious issue in terms of name
>collisions to be specious.  Sure, it is there.  But this line of
>discussion is just a ruse.  You make no mention of generate.  This too
>has had design and library implications.  Why is it exempt from
>discussion?  That's why my cynicism rules my judgment to think that
>something else is trying to be avoided.
>
>-Dennis
>
>-----Original Message-----
>From: owner-sv-bc@eda.org [mailto:owner-sv-bc@eda.org] On Behalf Of
>Steven Sharp
>Sent: Monday, April 25, 2005 3:53 PM
>To: btf@boyd.com; etf@boyd.com; sv-bc@eda.org; sv-ec@eda.org;
>cliffc@sunburst-design.com
>Subject: [sv-bc] Re: Config-keyword work-around - was: 
>potential command
>line option
>
>
>>There is a reasonable workaround for the config keyword issue. Users 
>>can do the following [workaround using `begin_keywords "1364-2001" 
>>omitted]
>
>There is a problem with this proposed solution.
>
>The only keywords in 1364-2001 that have caused problems in customer
>designs are certain ones in configs.  Those keywords don't really need
>to be reserved in Verilog source if configs are not allowed in Verilog
>source (which they technically are not).  As a result, NC-Verilog (and
>possibly other tools) support a dialect of 1364-2001 that does not
>reserve those keywords.  This dialect is very useful, since it can
>compile legacy Verilog-1995 without significant keyword issues, and can
>also compile legal Verilog-2001 designs.
>
>This means that there may be a significant amount of Verilog 
>code by now
>that uses the config keywords as identifiers, but also uses 
>Verilog-2001
>features.  The workaround you have suggested won't work for such code.
>
>As I mentioned in an earlier email, a compromise might be possible that
>takes advantage of `begin_keywords.  However, that compromise needs to
>take into account that in practice, those keywords didn't 
>really need to
>be reserved until configs were allowed in Verilog source files.  So it
>needs to support the intermediate dialect that doesn't reserve them.
>
>Steven Sharp
>sharp@cadence.com
>
>
>