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From: "Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>
Newsgroups: comp.lang.ada
Subject: Re: Curiosity about different integer types
Date: Sat, 18 Jun 2016 23:57:11 +0200
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Date: 2016-06-18T23:57:11+02:00
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On 2016-06-18 23:26, mockturtle wrote:

> few days ago a curiosity came to my mind.  Consider this
>
>   type Foo is new Integer range 0 .. 115;
>
>   type Bar is new Integer range -1000 .. 1000;
>
> My gut feeling is that, despite the fact that they are both derived
> from Integer, there is no guarantee that the "binary type" underneath
> them is the same. For example, Foo could be implemented as an 8-bit
> integer, while Bar could be implemented as a 16-bit integer, or maybe
> both could be implemented as (say) 32-bit integers.
>
> Am I right? I tried to do some experiments with gcc and both types
> are  implemented with the same binary type, but it could be only for
> efficiency reasons...

No. I am not a language lawyer, but

    type Foo is new Integer range 0 .. 115;

is a kind of  abbreviation of

    type <anonymous> is new Integer; -- Clone
    subtype Foo is <anonymous> range 0..115; -- Constrain

The relevant point is IMO ARM 3.4 (9)

-- 
Regards,
Dmitry A. Kazakov
http://www.dmitry-kazakov.de