From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (from majordomo@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id SAA28699; Sun, 13 Oct 2002 18:15:00 +0200 (MET DST) X-Authentication-Warning: pauillac.inria.fr: majordomo set sender to owner-caml-list@pauillac.inria.fr using -f Received: from concorde.inria.fr (concorde.inria.fr [192.93.2.39]) by pauillac.inria.fr (8.7.6/8.7.3) with ESMTP id SAA28783 for ; Sun, 13 Oct 2002 18:14:59 +0200 (MET DST) Received: from pauillac.inria.fr (pauillac.inria.fr [128.93.11.35]) by concorde.inria.fr (8.11.1/8.11.1) with ESMTP id g9DGEw528242; Sun, 13 Oct 2002 18:14:58 +0200 (MET DST) Received: (from xleroy@localhost) by pauillac.inria.fr (8.7.6/8.7.3) id SAA29139; Sun, 13 Oct 2002 18:14:58 +0200 (MET DST) Date: Sun, 13 Oct 2002 18:14:58 +0200 From: Xavier Leroy To: Pierre Weis Cc: Daniel de Rauglaudre , caml-list@inria.fr Subject: Re: [Caml-list] Runtime overflow and what to do Message-ID: <20021013181458.A28677@pauillac.inria.fr> References: <20021013120456.D7639@verdot.inria.fr> <200210131029.MAA17141@pauillac.inria.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Mailer: Mutt 1.0i In-Reply-To: <200210131029.MAA17141@pauillac.inria.fr>; from pierre.weis@inria.fr on Sun, Oct 13, 2002 at 12:29:58PM +0200 Sender: owner-caml-list@pauillac.inria.fr Precedence: bulk > [Overflow checking in integer multiplication] > (* [lenght_of_int] is the maximum number of bits in an integer. *) > let length_of_int = Sys.word_size - 2;; > > 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)) > > (* [num_bits_int n] returns the number of significant bits of an > integer. *) 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... Apologies for nit-picking; I couldn't resist! - Xavier Leroy ------------------- To unsubscribe, mail caml-list-request@inria.fr Archives: http://caml.inria.fr Bug reports: http://caml.inria.fr/bin/caml-bugs FAQ: http://caml.inria.fr/FAQ/ Beginner's list: http://groups.yahoo.com/group/ocaml_beginners