Re: What about big integers in Ada 2005?

[Simon Wright <simon@pushface.org>]

Martin Krischik <krischik@users.sourceforge.net> writes:

> Brian May wrote:
>
>> Question (from writing a communications protocol with a high level
>> programming language that turned out to a an extremely poor
>> choice[1]):
>
> package Interfaces is
> pragma Pure (Interfaces);
>
>    type Integer_8  is range -2 **  7 .. 2 **  7 - 1;
>    for Integer_8'Size use  8;
>
>    type Integer_16 is range -2 ** 15 .. 2 ** 15 - 1;
>    for Integer_16'Size use 16;
>
>    type Integer_32 is range -2 ** 31 .. 2 ** 31 - 1;
>    for Integer_32'Size use 32;
>
>    type Integer_64 is range -2 ** 63 .. 2 ** 63 - 1;
>    for Integer_64'Size use 64;
>
>    type Unsigned_8  is mod 2 **  8;
>    for Unsigned_8'Size use  8;
>
>    type Unsigned_16 is mod 2 ** 16;
>    for Unsigned_16'Size use 16;
>
>    type Unsigned_32 is mod 2 ** 32;
>    for Unsigned_32'Size use 32;
>
>    type Unsigned_64 is mod 2 ** 64;
>    for Unsigned_64'Size use 64;

This is GNAT. On the other hand, RM95 says

package Interfaces is
   pragma Pure(Interfaces);

   type Integer_n is range -2**(n-1) .. 2**(n-1) - 1;  --2's complement

   type Unsigned_n is mod 2**n;

..

 An implementation shall provide the following declarations in the
 visible part of package Interfaces:

* Signed and modular integer types of n bits, if supported by the
  target architecture, for each n that is at least the size of a
  storage element and that is a factor of the word size. The names of
  these types are of the form Integer_n for the signed types, and
  Unsigned_n for the modular types;