Re: Unsigned Longword

["Matthew Heaney" <matthew_heaney@acm.org>]

In article <OF8A70EE05.EDBCEFED-ON88256843.0079C931@ray.ca> , 
Tom_Hargraves@Raytheon.com  wrote:

> Anyway, at the time I really wanted a 'true' 32 bit 'Unsigned Longword'. One
> that went from 0..2**32-1, supported by associated +-/* operators. However, at
> the time, both of the compilers (DEC and VADS) had System packages which
> implemented unsigned longword as the Positive range of Integer, ie.
> 0..2**31-1. (An understandable implementation on a twos complement  machine).
> Thus a '+' arithmetic operation which caused a result whose MSB was set to '1'
> caused a constraint error.

VADS had a package called Unsigned_Types (or something like that) that
included true unsigned integers all the way up to and including 32 bits.
When you with'd that package, this turned on compiler magic, effectively
extending the language.


> I'd like to ask this forum if there was/is a nicer way of implementing a
> 'true' Unsigned Longword?

You could try suppressing overflow on the type:

  type Unsigned_Integer is new Integer;
  pragma Suppress (Overflow_Check, On => Unsigned_Integer);


--
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differences between kinds of organisms, patterns of distribution and
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Ernst Mayr