From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966016AbXCFStt (ORCPT ); Tue, 6 Mar 2007 13:49:49 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S966008AbXCFSts (ORCPT ); Tue, 6 Mar 2007 13:49:48 -0500 Received: from terminus.zytor.com ([192.83.249.54]:59808 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966004AbXCFStr (ORCPT ); Tue, 6 Mar 2007 13:49:47 -0500 Message-ID: <45EDB799.5080509@zytor.com> Date: Tue, 06 Mar 2007 10:48:57 -0800 From: "H. Peter Anvin" User-Agent: Thunderbird 1.5.0.9 (X11/20070212) MIME-Version: 1.0 To: Andi Kleen CC: David Miller , shemminger@linux-foundation.org, jengelh@linux01.gwdg.de, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [RFC] div64_64 support II References: <20070226143127.5c74bec9@freekitty> <20070305155714.3abe1b5e@freekitty> <20070305.162551.41660347.davem@davemloft.net> <20070306140412.GA1470@one.firstfloor.org> In-Reply-To: <20070306140412.GA1470@one.firstfloor.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: >> The problem with these algorithms that tradoff one or more >> multiplies in order to avoid a divide is that they don't >> give anything and often lose when both multiplies and >> divides are emulated in software. > > Actually on rereading this: is there really any Linux port > that emulates multiplies in software? I thought that was only > done on really small microcontrollers or smart cards; but anything > 32bit+ that runs Linux should have hardware multiply, shouldn't it? SPARC < v8 does multiplies using an MSTEP instruction. -hpa