Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Programming > VHDL > Re: VHDL syntax

Thread Tools

Re: VHDL syntax

Posts: n/a
On Apr 23, 4:36 pm, Jim Lewis <(E-Mail Removed)> wrote:
> Grumps,
> > What synthesiser feature/specification suggests compliance?

> IEEE 1076.6 specifies VHDL RTL Coding. Unfortunately 1076.6-2004
> (the most current) states:
> For a discrete range that appears as part of a slice name,
> the bounds of the discrete range shall be specified
> directly or indirectly as static values belonging to an
> integer type.
> I am not sure about your application, but for some of mine,
> this needs to be updated.
> In general, if you have issues of language compliance, in which
> different vendors disagree or you and a vendor disagree, and
> you can get cooperation from the vendor, you can
> also get an official language resolution from the VHDL Issues
> Screening and Analysis Committee (ISAC). Please make sure to
> keep the vendor's name out of the issue report - the ISAC worries
> about compliance - once you receive the compliance report, you
> can deal with the vendor. =You can report issues to ISAC at:
> For synthesis issues click on: "Report a BUG on an IEEE VHDL revision"
> Best Regards,
> Jim Lewis
> IEEE VHDL and Analysis Standards Group (VASG) Chair
> SynthWorks VHDL Training

While most synthesis tools will accept non-static expression in
ranges, they also usually must implement the computational circuitry
for those expressions in hardware.

If it is possible to code it in a for loop with an if statement,
comparing the unadulterated signal to an expression of the index, then
the index is treated as if "static" when the loop is unrolled, and the
computation of the expression is not done in hardware. Therefore such
expressions are also not limited by what is implementable in hardware
(i.e. divide/modulo by non-integral-powers of two, etc.).


Reply With Quote

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Syntax Checker that's better than the normal syntax checker Jacob Grover Ruby 5 07-18-2008 05:07 AM
Syntax bug, in 1.8.5? return not (some expr) <-- syntax error vsreturn (not (some expr)) <-- fine Good Night Moon Ruby 9 07-25-2007 04:51 PM
VHDL-2002 vs VHDL-93 vs VHDL-87? afd VHDL 1 03-23-2007 09:33 AM
[ANN] SqlStatement 1.0.0 - hide the syntax of SQL behind familiarruby syntax Ken Bloom Ruby 3 10-09-2006 06:46 PM
Syntax highligth with textile: Syntax+RedCloth ? gabriele renzi Ruby 2 12-31-2005 02:44 AM