From mboxrd@z Thu Jan  1 00:00:00 1970
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From: bobduff@world.std.com (Robert A Duff)
Subject: Re: Rep Clause Vaues??
Date: 1997/01/24
Message-ID: <E4IrC3.IGG@world.std.com>#1/1
X-Deja-AN: 212101579
references: <5c3oh5$7oh@uuneo.neosoft.com>
 <01bc0862$77b689c0$018c71a5@dhoossr.iquest.com>
organization: The World Public Access UNIX, Brookline, MA
newsgroups: comp.lang.ada
Date: 1997-01-24T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <01bc0862$77b689c0$018c71a5@dhoossr.iquest.com>,
David C. Hoos, Sr. <david.c.hoos.sr@ada95.com> wrote:
>-- E.g., for Mechs'Size use Integer'Size.
...
>type Mechs_Bit_Pattern_Type is new Integer range 0 .. 2 ** Mechs'Size -1;
>for Mechs_Bit_Pattern_Type'Size use Mechs'Size;

If Mechs'Size = Integer'Size, then Integer'Last is probably
2**(Mechs'Size-1)-1, so the above will overflow.

I suspect you meant:

    type Mechs_Bit_Pattern_Type is range 0 .. 2 ** Mechs'Size -1;

which will work fine, IF the implementation supports integer types
bigger than Integer.

If you want an unsigned type that is the same size as the biggest
supported signed integer, then you have to use modular types, which is
unfortunate, because you lose overflow checking.  (It's unfortunate if
you *want* overflow checking, that is.)

- Bob