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From: bobduff@world.std.com (Robert A Duff)
Subject: Re: An interesting quote on Java and C++
Date: 1997/09/22
Message-ID: <EGxFsv.9yF@world.std.com>#1/1
X-Deja-AN: 274605605
References: <5ujjvq$t4s@drn.zippo.com> <EGEq96.2H6@world.std.com>
 <34218E68.63D5@gsg.eds.com> <dewar.874759791@merv>
Organization: The World Public Access UNIX, Brookline, MA
Newsgroups: comp.lang.ada
Date: 1997-09-22T00:00:00+00:00
List-Id: <comp.lang.ada>


In article <dewar.874759791@merv>, Robert Dewar <dewar@merv.cs.nyu.edu> wrote:
>Note that in Ada, wrap around (modular) types *do* have completely portable
>semantics, although in practice people will choose types that match thei
>hardware, ...

Not quite true.  3.5.4(27) allows special treatment of one's comp
machines.  (And there's an AI that worries about what the heck that
paragraph means.)  This is again the "efficiency over portability" way.

Note that modular types are not just about modular arithmetic -- they
also support bit-wise logical operations.  On a one's complement
machine, you still want to be able to have all-ones as a bit pattern, if
you're using these things as bit patterns, even though it's
arithmetically equal to zero.

- Bob