Re: EXTERNAL: Re: [vhdl-200x] RE: Modular types

From: Brian Drummond <brian@shapes.demon.co.uk>
Date: Mon Aug 04 2014 - 00:49:20 PDT
On Mon, 2014-08-04 at 08:03 +0200, tgingold@free.fr wrote:
> > I don't know what it implies for VHDL implementors but in the end,
> > this would help reduce the amount of work for future language
> > revisions
> > since people would be able to experiment and play, and even actually
> > use the features that they need for their job, without interfering
> > with VHDL's philosophy or core principles. I like it :-)
> 
> But you can do such experiment already today (and even with vhdl 87):
> declare a record type with one integer element, add declare all the
> operations you need: +, -, and, or, ...
> 
> No need to perverse an existing feature to do experimentations.

I think Whygee's point is that while there are ways of experimenting
with the semantics today, using records, what he wants is the
performance of native boolean/shift operators on integer-like
quantities.

My suspicion is that adding modular types natively will get close to the
performance gain he wants (compiling down to native machine
instructions), but that adding the semantics via heavier tools like
resolution functions - or records - might add most of the performance
penalty of signals over variables and thus destroy what he wants to
accomplish.

Your vastly greater knowledge of a simulator implementation may shed
some light on this.

- Brian


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Received on Mon Aug 4 00:49:40 2014

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