From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752592AbYGYUyi (ORCPT ); Fri, 25 Jul 2008 16:54:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751027AbYGYUya (ORCPT ); Fri, 25 Jul 2008 16:54:30 -0400 Received: from sj-iport-2.cisco.com ([171.71.176.71]:45749 "EHLO sj-iport-2.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750827AbYGYUy3 (ORCPT ); Fri, 25 Jul 2008 16:54:29 -0400 X-IronPort-AV: E=Sophos;i="4.31,253,1215388800"; d="scan'208";a="69277966" From: Roland Dreier To: Andrew Morton Cc: "H. Peter Anvin" , joerg.roedel@amd.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH] introduce lower_32_bits() macro References: <1216998747-16896-1-git-send-email-joerg.roedel@amd.com> <4889FA03.6010708@zytor.com> <20080725134759.ae19b883.akpm@linux-foundation.org> X-Message-Flag: Warning: May contain useful information Date: Fri, 25 Jul 2008 13:54:28 -0700 In-Reply-To: <20080725134759.ae19b883.akpm@linux-foundation.org> (Andrew Morton's message of "Fri, 25 Jul 2008 13:47:59 -0700") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.0.60 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-OriginalArrivalTime: 25 Jul 2008 20:54:28.0571 (UTC) FILETIME=[A11FBAB0:01C8EE98] Authentication-Results: sj-dkim-3; header.From=rdreier@cisco.com; dkim=pass ( sig from cisco.com/sjdkim3002 verified; ); Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > There's some readability benefit. Sometimes it is hard to understand > why some random open-coded cast was used. But I seem to recall that > there was another reason why we decided we needed this. I forget, and > so apparently did the changelog author ;) The guy who added the macro explained it in a comment ;) * A basic shift-right of a 64- or 32-bit quantity. Use this to suppress * the "right shift count >= width of type" warning when that quantity is * 32-bits. - R.