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From: "Nick Roberts" <Nick.Roberts@dial.pipex.com>
Subject: Re: Bignum modular types in Ada95
Date: 1998/01/31
Date: 1998-01-31T00:00:00+00:00	[thread overview]
Message-ID: <01bd2e95$e917d560$LocalHost@xhv46.dial.pipex.com> (raw)
In-Reply-To: EnKEtu.KGp@world.std.com


I'm fairly sure that arbitrary-precision provision would be sensible for
both integer and fixed-point (possibly including decimal) types, but not
for floating-point types.

The reason for fixed-point support is that there will be many applications
requiring fixed-point types with huge ranges/accuracy (e.g.
astro-navigation (this is not a joke :-)) besides cryptography;
implementation is not an issue, since fixed-point types are (always?)
implemented as integer types anyway.

I suspect that no-one would want to use a floating-point type that couldn't
use the target machine's floating-point hardware.  Some RISC machines might
be able to do arbitrary-length floating point arithmetic (and maybe some
machines of the future), but I'm not sure that there would be a demand for
this functionality, in practice.  Would there?

-- 

== Nick Roberts ================================================
== Croydon, UK                       ===========================
==                                              ================
== Proprietor, ThoughtWing Software                   ==========
== Independent Software Development Consultant            ======
== Nick.Roberts@dial.pipex.com                              ====
== Voicemail & Fax +44 181-405 1124                          ===
==                                                            ==
==           I live not in myself, but I become               ==
===          Portion of that around me; and to me             ==
====         High mountains are a feeling, but the hum        ==
=======      Of human cities torture.
===========                             -- Byron [Childe Harold]


Robert A Duff <robertduff@world.std.com> wrote in article
<EnKEtu.KGp@world.std.com>...
> In article <34D082F9.ABEC0D3B@elca-matrix.ch>,
> Mats Weber  <Mats.Weber@elca-matrix.ch> wrote:
[snip]
> >- Only integers or reals as well ?
> 
> Reals?  No, just integers and rationals, which is exactly what is
> already supported at compile time (e.g. "X: constant :=
> 1_000_000_000_000/3_000_000_000_000;" has to be *exactly* one-third in
> current Ada compilers).  I'm not asking for an exact representation of
> the square root of 2 or pi or e!





  parent reply	other threads:[~1998-01-31  0:00 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
1998-01-27  0:00 Bignum modular types in Ada95 Markus Kuhn
1998-01-28  0:00 ` Dmitriy Anisimkov
1998-01-28  0:00 ` Nick Roberts
1998-01-28  0:00   ` Nick Roberts
1998-02-01  0:00     ` Robert Dewar
1998-02-07  0:00       ` Nick Roberts
1998-02-09  0:00         ` Robert Dewar
1998-01-28  0:00   ` Larry Kilgallen
1998-01-28  0:00 ` Markus Kuhn
1998-01-28  0:00   ` Brian Rogoff
1998-01-29  0:00     ` Markus Kuhn
1998-01-30  0:00       ` Brian Rogoff
1998-02-01  0:00   ` Robert Dewar
1998-02-02  0:00     ` Tarjei T. Jensen
1998-02-02  0:00       ` Robert Dewar
1998-02-03  0:00         ` Tarjei T. Jensen
1998-02-04  0:00           ` Keith Thompson
     [not found]   ` <EnIIvn.3zr@world.std.com>
1998-01-29  0:00     ` Mats Weber
     [not found]       ` <EnKEtu.KGp@world.std.com>
1998-01-30  0:00         ` Markus Kuhn
1998-01-30  0:00           ` Mats Weber
1998-01-30  0:00             ` Markus Kuhn
1998-01-31  0:00               ` Nick Roberts
1998-02-01  0:00           ` Robert Dewar
1998-01-30  0:00         ` Mats Weber
1998-02-01  0:00           ` Robert Dewar
1998-02-01  0:00           ` Robert Dewar
1998-01-31  0:00         ` Nick Roberts [this message]
1998-02-01  0:00         ` Robert Dewar
1998-01-29  0:00     ` Markus Kuhn
1998-01-31  0:00       ` Nick Roberts
1998-02-01  0:00     ` Robert Dewar
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