Re: [vhdl-200x] Proposal for improved physical types

From: Daniel Kho <daniel.kho@tauhop.com>
Date: Sat Jan 10 2015 - 00:00:04 PST
Jan Decaluwe explains this clearly in one of his suggestions, and which I
also agree:

-- JanDecaluwe <http://www.eda-twiki.org/cgi-bin/view.cgi/Main/JanDecaluwe> -
2014-11-02 My suggestion is to implement this similar to vector types:
allow unconstrained types (e.g. UNIVERSAL_INTEGER) in interfaces, but
require finite constraints at elaboration time. This would provide the
modeling advantages of arbitrary length integers while keeping the
advantage of a compiled language: the elaborator/compiler could perform
optimizations based on the constraints. This should address any performance
concerns.


On 10 January 2015 at 15:27, Daniel Kho <daniel.kho@tauhop.com> wrote:

> Tristan,
> As from what I understand from the ArbitraryIntegers proposal, it is not
> suggesting to have infinite precision integers at simulation/elaboration
> time. It is merely suggesting to have unconstrained integers (yes, infinite
> precision if you may) prior to being constrained later at a higher-level
> hierarchy of the design, which makes the design synthesizable and finite.
>
> -daniel
>
>
> On 10 January 2015 at 15:13, Tristan Gingold <tgingold@free.fr> wrote:
>
>> On 10/01/15 07:46, Daniel Kho wrote:
>>
>>> This is one of the reasons I am supporting the proposal for extended or
>>> arbitrary-length integers:
>>> http://www.eda-twiki.org/cgi-bin/view.cgi/P1076/ArbitraryIntegers
>>>
>>
>> I still think this proposal is not clear enough.  If infinite precision
>> integers (at simulation time) are proposed, that's awful from a
>> performance point of view.
>>
>> I repeat: I am ok with infinite precision at analysis time, and
>> not against any but fixed precision at simulation time; but
>> certainly not ok with infinite precision at simulation time.
>>
>> All integer types must have bounds.
>>
>>
>> Tristan.
>>
>>
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>>
>

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Received on Sat Jan 10 00:01:35 2015

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