From: Michel Quercia <michel.quercia@prepas.org>
To: caml-list@inria.fr
Subject: Re: [Caml-list] Runtime overflow and what to do
Date: Sun, 13 Oct 2002 19:06:36 +0200 [thread overview]
Message-ID: <200210131906.36527.michel.quercia@prepas.org> (raw)
In-Reply-To: <20021013181458.A28677@pauillac.inria.fr>
Le Dimanche 13 Octobre 2002 18:14, Xavier Leroy a écrit :
> > [Overflow checking in integer multiplication]
> > let ( * ) n m =
> > if num_bits_int n + num_bits_int m < length_of_int
> > then n * m else raise (Overflow ("*", string_of_int n, string_of_int m))
> Hmmph... this definition raises Overflow when computing
> min_int * 1, or (min_int / 2) * 2, while these products are actually
> representable within a machine integer...
What about this one ?
let mul a b =
if a = 0 then 0
else
let x = a*b in
let q = x/a and r = x mod a in
if (q = b) & (r = 0) then x else raise Overflow
--
Michel Quercia
23 rue de Montchapet, 21000 Dijon
http://michel.quercia.free.fr (maths)
http://pauillac.inria.fr/~quercia (informatique)
mailto:michel.quercia@prepas.org
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next prev parent reply other threads:[~2002-10-13 17:07 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-10-10 15:01 Scott J,
2002-10-10 15:07 ` Maxence Guesdon
2002-10-10 15:11 ` Maxence Guesdon
2002-10-10 15:21 ` Luc Maranget
2002-10-10 18:13 ` Sven LUTHER
2002-10-10 18:57 ` Xavier Leroy
2002-10-10 22:17 ` Scott J,
2002-10-11 8:00 ` Sven LUTHER
2002-10-11 10:16 ` Alessandro Baretta
2002-10-12 16:13 ` John Carr
2002-10-12 16:58 ` Sven LUTHER
2002-10-12 17:12 ` John Prevost
2002-10-13 9:31 ` Xavier Leroy
2002-10-13 9:52 ` Sven LUTHER
2002-10-13 9:57 ` Xavier Leroy
2002-10-13 10:15 ` Sven LUTHER
2002-10-13 13:25 ` John Carr
2002-10-13 9:28 ` Xavier Leroy
2002-10-14 0:56 ` Chris Hecker
2002-10-14 9:46 ` Jacques Garrigue
2002-10-14 11:02 ` Scott J,
2002-10-14 14:05 ` Tim Freeman
2002-10-14 15:32 ` Stefano Zacchiroli
2002-10-14 16:12 ` Alain Frisch
2002-10-14 16:49 ` [Caml-list] new ocaml switches (was Re: Runtime overflow and what to do) Chris Hecker
2002-10-13 9:25 ` [Caml-list] Runtime overflow and what to do Xavier Leroy
2002-10-13 10:04 ` Daniel de Rauglaudre
2002-10-13 10:29 ` Pierre Weis
2002-10-13 10:47 ` Daniel de Rauglaudre
2002-10-13 12:38 ` Pierre Weis
2002-10-13 16:14 ` Xavier Leroy
2002-10-13 17:06 ` Michel Quercia [this message]
2002-10-15 19:15 ` Pierre Weis
2002-10-15 19:25 ` Xavier Leroy
2002-10-16 8:24 ` Pierre Weis
2002-10-13 10:19 ` Pierre Weis
2002-10-11 8:02 ` Sven LUTHER
2002-10-11 6:42 ` Florian Hars
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