From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761679AbZENOQr (ORCPT ); Thu, 14 May 2009 10:16:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761651AbZENOQ0 (ORCPT ); Thu, 14 May 2009 10:16:26 -0400 Received: from terminus.zytor.com ([198.137.202.10]:36701 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761573AbZENOQZ (ORCPT ); Thu, 14 May 2009 10:16:25 -0400 Message-ID: <4A0C27AA.4010006@zytor.com> Date: Thu, 14 May 2009 07:16:10 -0700 From: "H. Peter Anvin" User-Agent: Thunderbird 2.0.0.14 (X11/20080501) MIME-Version: 1.0 To: Andi Kleen CC: Sheng Yang , linux-kernel@vger.kernel.org, linux-mm , Ingo Molnar Subject: Re: [PATCH] x86: Extend test_and_set_bit() test_and_clean_bit() to 64 bits in X86_64 References: <1242202647-32446-1-git-send-email-sheng@linux.intel.com> <87zldhl7ne.fsf@basil.nowhere.org> <200905141145.05591.sheng@linux.intel.com> <20090514083250.GD19296@one.firstfloor.org> <4A0C262B.3060303@zytor.com> <20090514141649.GD10933@one.firstfloor.org> In-Reply-To: <20090514141649.GD10933@one.firstfloor.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Andi Kleen wrote: >>> >> The right way to do it is to pass the proper type of register. > > For the input index register you don't actually need 64bit and for the > value it's typically memory anyways. > If you have a 64-bit operation you have a 64-bit index register. And you need a 64-bit index for it to handle over 2^31 (since it is signed.) -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.