From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965294AbWHOIaE (ORCPT ); Tue, 15 Aug 2006 04:30:04 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S965298AbWHOIaD (ORCPT ); Tue, 15 Aug 2006 04:30:03 -0400 Received: from mx1.redhat.com ([66.187.233.31]:8068 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S965294AbWHOIaA (ORCPT ); Tue, 15 Aug 2006 04:30:00 -0400 From: David Howells In-Reply-To: References: <20060814211504.27190.10491.stgit@warthog.cambridge.redhat.com> <20060814211507.27190.61876.stgit@warthog.cambridge.redhat.com> To: Andi Kleen Cc: David Howells , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org# Subject: Re: [RHEL5 PATCH 1/4] Provide fallback full 64-bit divide/modulus ops for gcc X-Mailer: MH-E 8.0; nmh 1.1; GNU Emacs 22.0.50 Date: Tue, 15 Aug 2006 09:29:57 +0100 Message-ID: <7510.1155630597@warthog.cambridge.redhat.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: > At least Linus' traditional argument against this is that it's better > to open code these (do_div) so that it's clear to the coder that they > are really costly. do_div() is not a full replacement for __udivdi3(), __umoddi3() or __udivmoddi4(), though I suspect we don't need divisor >= 2^32 anywhere atm. There are places where the compiler emits these that aren't entirely obvious, one of which IIRC is in ext2 inode allocation. David