Re: 64-bit integers in Ada

["Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org>]

One advantage to insisting that the type Integer supports at least 16 bits
is that it gives the developer some minimal parameters on which to write
software that might rely on the standard type Integer. If you won't
guarantee that the type Integer has some minimal usefulness, then why bother
to have it at all? Most hardware will support 16 bits and even if it doesn't
you might find it difficult to write any useful programs if you can't count
up to at least 32767, so a software simulation is probably necessary.

Is there a case where, for example, it would make any sense at all for an
implementation to *not* give the user 16 bits? Would it ever make sense for
the type Integer to be 8 bits, for example? (Assuming that if I actually
want an 8-bit integer type I can still declare one of my own, that is...)
Would anyone ever really want to build an Ada implementation that had a
maximum integer of something less than 16 bits? If not, then the ARM
specifying support for at least 16 bits is a good thing in terms of giving
the developer a warm fuzzy feeling that he can depend on at least that much.

For what its worth, IIRC, the XD-Ada compiler for the Mil-Std-1750a had 16
bits for the standard type Integer. I don't remember if it allowed
declarations of integers larger than this, but my vague memory was that it
did not. Given the machine architecture and the intended usage, it would not
have been an unreasonable restriction.

MDC
--
Marin David Condic
Senior Software Engineer
Pace Micro Technology Americas    www.pacemicro.com
Enabling the digital revolution
e-Mail:    marin.condic@pacemicro.com


"Robert A Duff" <bobduff@shell01.TheWorld.com> wrote in message
news:wcc65ywhw3s.fsf@shell01.TheWorld.com...
>
> Actually, Ada requires 16 bit integers (at minimum).
> Robert has argued in the past that this is silly -- too small to be of
> use, and better to let the market decide.  Probably true.
>