From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263771AbUBRFGv (ORCPT ); Wed, 18 Feb 2004 00:06:51 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263661AbUBRFGv (ORCPT ); Wed, 18 Feb 2004 00:06:51 -0500 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:5610 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S263771AbUBRFFD (ORCPT ); Wed, 18 Feb 2004 00:05:03 -0500 Date: Wed, 18 Feb 2004 05:04:57 +0000 From: viro@parcelfarce.linux.theplanet.co.uk To: Linus Torvalds Cc: Dave Jones , Benjamin Herrenschmidt , Santiago Leon , Linux Kernel list , Jeff Garzik Subject: Re: [PATCH][2.6] IBM PowerPC Virtual Ethernet Driver Message-ID: <20040218050457.GZ8858@parcelfarce.linux.theplanet.co.uk> References: <40329A24.5070209@us.ibm.com> <1077065118.1082.83.camel@gaston> <20040218040130.GC26304@redhat.com> <20040218042340.GW8858@parcelfarce.linux.theplanet.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 17, 2004 at 08:46:52PM -0800, Linus Torvalds wrote: > > ago. Any assumptions regarding their allocation are non-portable. > > Well, to be fair, most compilers still aim to make them useful. > > There's a difference between "the standard doesn't guarantee anything" and > "the implementation makes no sense". > > (Sadly, a lot of compiler people do seem to look to standards more than > actual users for guides to do things, but at the same time I do believe > that gcc has useful semantics for bitfields and hardware accesses. You > just have to know what the implementation-specific rules are) True. However, most of the bitfield uses I've seen would become much cleaner from rewrite to explicit mask-and-shift stuff.