From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail2-relais-roc.national.inria.fr (mail2-relais-roc.national.inria.fr [192.134.164.83]) by walapai.inria.fr (8.13.6/8.13.6) with ESMTP id p4SFwktC031486 for ; Sat, 28 May 2011 17:58:46 +0200 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: Av0EAEMa4U1QRFuw/2dsb2JhbABVpj93xWOGHgSfag X-IronPort-AV: E=Sophos;i="4.65,286,1304287200"; d="scan'208";a="95623770" Received: from furbychan.cocan.org ([80.68.91.176]) by mail2-smtp-roc.national.inria.fr with ESMTP/TLS/AES256-SHA; 28 May 2011 17:58:41 +0200 Received: from rich by furbychan.cocan.org with local (Exim 4.72) (envelope-from ) id 1QQLuS-00084d-0o; Sat, 28 May 2011 16:58:40 +0100 Date: Sat, 28 May 2011 16:58:40 +0100 From: "Richard W.M. Jones" To: Dario Teixeira Cc: caml-list@inria.fr Message-ID: <20110528155839.GA9002@annexia.org> References: <4DDFDC1F.5050605@inria.fr> <165028.34675.qm@web111509.mail.gq1.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <165028.34675.qm@web111509.mail.gq1.yahoo.com> User-Agent: Mutt/1.5.18 (2008-05-17) Subject: Re: [Caml-list] Re: Binary logarithm of a power of 2 On Fri, May 27, 2011 at 11:04:16AM -0700, Dario Teixeira wrote: > Note that __builtin_ctz actually translates into a single opcode where > available (BSFL in x86_64), and I expect that a modern CPU will do a > decent job with it. Therefore, despite that a C-based solution will > most likely prevent inlining (right?), it may be hard to beat... It's long been on my OCaml wishlist (along with a 'return' statement) to be able to use inline asm. Rich. -- Richard Jones Red Hat