From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755102Ab1LVPwq (ORCPT ); Thu, 22 Dec 2011 10:52:46 -0500 Received: from mail-iy0-f174.google.com ([209.85.210.174]:59585 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754115Ab1LVPwm (ORCPT ); Thu, 22 Dec 2011 10:52:42 -0500 Message-ID: <4EF35243.9030600@gmail.com> Date: Thu, 22 Dec 2011 23:52:35 +0800 From: "nai.xia" User-Agent: Mozilla/5.0 (X11; Linux i686; rv:8.0) Gecko/20111124 Thunderbird/8.0 MIME-Version: 1.0 To: Linus Torvalds CC: Brian Gerst , Andi Kleen , Linux-MM , LKML Subject: Re: Question about missing "cld" in x86 string assembly code References: <201112172258.24221.nai.xia@gmail.com> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2011年12月18日 02:39, Linus Torvalds wrote: > On Sat, Dec 17, 2011 at 9:08 AM, Brian Gerst wrote: >> >> The i386 ELF ABI states "The direction flag must be set to the >> ‘‘forward’’ (that is, zero) direction before entry and upon exit from >> a function." Therefore it can be assumed to be clear, unless >> explicitly set. > > The exception, of course, being bootup, fault and interrupt handlers, > and after we've called out to foreign code (ie BIOS). Yeah, I think I see these cld's now. Thanks for the answers! Nai > > So there *are* a few cld's sprinkled around, they are just fairly rare. > > Linus