Re: Does Ada support endiannes?

["Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de>]

On Wed, 14 Dec 2011 08:16:02 -0800 (PST), Gerd wrote:

> On 13 Dez., 15:19, Gautier write-only <gautier_niou...@hotmail.com>
> wrote:
> 
> Are you sure the "/" and mod would work correct?

Always. Arithmetic is complete in the sense that any possible function can
be implemented using these operations.

> Assume, that the Value 16#000000FF# shall be converted to
> 16#FF000000#
>
> Native : Integer := 16#000000FF#;
> 
> Remote : Integer;
> 
> Remote := 16#01000000# * ()Native mod 16#000000FF#); -- overflow!

Either it is not Integer (e.g. Unsigned_32) or else overflow is not an
error but a legal outcome indicating protocol error, for example. The
decision depends on the application.

Note that if you used a representation clause and/or Unchecked_Conversion,
you would have to use X'Valid attribute in order to check obtained value
for being an integer.

For all cases where arithmetic would raise Constraint_Error, X'Value should
yield false, which is not guaranteed of course. This is another reason why
not to use representation clauses, because some illegal representation
might get misinterpreted as proper values.

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