From: Clifford E. Cummings (firstname.lastname@example.org)
Date: Sun Apr 24 2005 - 20:50:12 PDT
Hi, All -
Another new subject line to separate out the issues.
· I wrote the Verilog-2001 BNF - it was far better than the
Verilog-1995 BNF but it still had errors.
· In 1996 I helped champion the effort to put configurations on the
· Tom Fitzpatrick and I championed the Verilog-1995 the config
proposal for Verilog-2001
· config, endconfig and library were intended to be Verilog keywords
(see Draft-4 Annex B include in my email of 4/21/2005)
· The config proposal was intended to make it possible to instantiate
two modules with the same name but from different source files without
modifying the source files, which was required by the non-standard `uselib
directive . It also was intended to eliminate the need for the
-v -y +libext+.v+ and many -f command line switches, not to substitute
other switches in their place.
· At least one tool has implemented configs according to the
implementation that I envisioned when I helped propose configurations.
· I wrote the Verilog-2001 BNF and it had many errors.
· We have not required vendors to implement error-BNF syntax once we
have identified the errors.
· There have been many places in the standard where the informative
examples helped to identify errors in the normative BNF. When we find
discrepancies, we as a committee discuss the differences and decide what
needs to be changed. In some cases, it is the BNF that needs to be changed.
· Although we should make every effort to make the BNF perfect, the
BNF is not perfect and the BNF-alone should not constitute the final word
regarding correct Verilog syntax
· We should clarify whatever we think is the right thing to do with
configs. This is a group decision.
· I guess the follow-on question is, do we really want to set a
precedent that might allow a vendor to implement a SystemVerilog feature
and then have other companies come back a few years later and request a
significant change to the feature to make it easier to implement on another
tool? Because, as you all have seen, I have a long memory for this type of
Regards - Cliff
Cliff Cummings - Sunburst Design, Inc.
14314 SW Allen Blvd., PMB 501, Beaverton, OR 97005
Phone: 503-641-8446 / FAX: 503-641-8486
email@example.com / www.sunburst-design.com
Expert Verilog, SystemVerilog, Synthesis and Verification Training
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