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Re: gEDA-user: Open VHDL Simulators?



Attila Kinali wrote:
> On Fri, 25 Apr 2008 14:04:38 -0700
> Stephen Williams <steve-TQXSILARuq3QT0dZR+AlfA@xxxxxxxxxxxxxxxx> wrote:
> 
>> As you know, this year's Icarus Verilog GSoC candidate is working
>> on a VHDL code generator back-end for Icarus Verilog. Hooray!
>> But suddenly the obvious question comes up, "How are we going to
>> run these generated files?" I'm here looking for suggestions.
> 
> After rethinking about this. What speaks against adding
> a VHDL front-end to Icarus? VHDL and Verilog are feature wise
> very similar and those few differences are not that difficult.
> As a special benefit it would give us the first OSS simulator
> with both VHDL and Verilog support.

It's not so obvious how that would work, or even whether it would
be a good idea. One possibility might be to have e.g. the freehdl
compiler generate vvp output, but would that be of use to anyone?
Currently, vvp doesn't do any kind of linking, but if it did
support linking, and if there is a VHDL compiler that can generate
vvp code, then that could lead to a mixed language simulator,
but the vvp semantics may not be a good match for VHDL.

Anyhow, the parsing of VHDL is actually relatively easy, things
get exciting when elaboration happens. That's where most of the
VHDL complexity lives. That is to some degree true of Verilog
as well, and most of the Icarus Verilog compiler is parse and
elaborate. The code generator parts are a small part of the tool
itself.

I have a copy of 1076-1993 already. I got it when I was deciding
which (Verilog or VHDL) to do. It's kinda dusty at the moment.

If someone really wants to pursue this from the development
perspective, then iverilog-devel at lists.sourceforge.net is
where Icarus Verilog development talk happens.
-- 
Steve Williams                "The woods are lovely, dark and deep.
steve at icarus.com           But I have promises to keep,
http://www.icarus.com         and lines to code before I sleep,
http://www.picturel.com       And lines to code before I sleep."


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