From: rouillard@acm.org (Jacques Rouillard)
Subject: Re: ADA - VHDL
Date: 1996/07/09
Date: 1996-07-09T00:00:00+00:00 [thread overview]
Message-ID: <rouillard-0907962020220001@mac-rouillard.imt-mrs.fr> (raw)
In-Reply-To: 31E2391F.A16BEBD@sh.bel.alcatel.be
In article <31E2391F.A16BEBD@sh.bel.alcatel.be>, "P. Cnudde VH14 (8218)"
<cnuddep@sh.bel.alcatel.be> wrote:
> Hello,
>
> As a "experienced" VHDL programmer and now looking for the
> first time really into ADA I have some historical questions
> and I hoped that somebody on those two newsgroups could help me
> making some points more clear.
>
> I agree there are a lot of similarities between the languages, but I do
> not understand the reason for many differences. There are things which
> I can not do in VHDL which I can in ADA and for which I see no reason.
> some examples:
> type new Integer;
You're right that you can have integer types in VHDL but you can't have a
new integer. I think the main reason is complexity.
> generics;
Ibidem. Genericity in Ada is an order of magnitude more complex than in VHDL.
> variant records
Here there is a fundamental reason: signals are defined based on
scalarity. The very notion of event is at risk if you have variant
records. This was examined in a special session of the ballot resolution
group, and the only workable solution led to a separation of the notion of
scalar type (which you can't cut into parts) from atomic type (of which
you can make a signal). Abandonned because of complexity.
>
> on the other hand there are also points which are more flexible in VHDL
>
> I also see no reason for some syntax differences ("to" in VHDL, ".." in ADA)
>
In Ada you don't have downtos which were felt a must when you have to deal
with hardware busses.
> I agree the differences may be small but to my oppinion it will cause problems
> in the future where hardware-software codesign will come a reallity and
a single
> language we be needed. I think that VHDL-ADA is a very powerfull
combination but
> would it not be possible to get the small differences between the
languages out of
> way and grow to a single language capable of discribing both: VHDL-ADA-2000
>
> What are the oppinions of the experts on this point?
Unfortunatly IMHO the two languages have diverged to a point that a
VHDL-ADA is not realistic. The similarities between the two languages are
a danger more than a clue, most of the time.
-- Jacques Rouillard
USA http://vhdl.org/~rouillard EU http://ismea.imt-mrs.fr/~rouillar
next prev parent reply other threads:[~1996-07-09 0:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
1996-07-09 0:00 ADA - VHDL P. Cnudde VH14 (8218)
1996-07-09 0:00 ` Jacques Rouillard [this message]
1996-07-10 0:00 ` Paul B. Graham
1996-07-10 0:00 ` Robert Dewar
1996-07-11 0:00 ` Michael Feldman
1996-07-10 0:00 ` Laurent Gasser
1996-07-11 0:00 ` P. Cnudde VH14 (8218)
1996-07-12 0:00 ` Paul B. Graham
1996-07-11 0:00 ` Robert Dewar
1996-07-15 0:00 ` Brian "Cheebie" Merchant
1996-07-16 0:00 ` jos de laender vh14 7461
1996-07-16 0:00 ` P. Cnudde VH14 (8218)
1996-07-16 0:00 ` Stephen A. Bailey
1996-07-22 0:00 ` Nick Weavers
1996-07-11 0:00 ` Jens Hansson
1996-07-11 0:00 ` Jean-Marc Bourguet
1996-07-12 0:00 ` Jean-Marc Bourguet
1996-07-13 0:00 ` Michael Feldman
1996-07-17 0:00 ` Chris Papademetrious
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