Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S269470AbUIRNGS (ORCPT ); Sat, 18 Sep 2004 09:06:18 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S269464AbUIRNFu (ORCPT ); Sat, 18 Sep 2004 09:05:50 -0400 Received: from colo.khms.westfalen.de ([213.239.196.208]:42390 "EHLO colo.khms.westfalen.de") by vger.kernel.org with ESMTP id S269470AbUIRNFq (ORCPT ); Sat, 18 Sep 2004 09:05:46 -0400 Date: 18 Sep 2004 11:46:00 +0200 From: kaih@khms.westfalen.de (Kai Henningsen) To: linux-kernel@vger.kernel.org Message-ID: <9H7p12YXw-B@khms.westfalen.de> In-Reply-To: Subject: Re: Being more careful about iospace accesses.. X-Mailer: CrossPoint v3.12d.kh14 R/C435 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Organization: Organisation? Me?! Are you kidding? References: <1095337514.9144.2344.camel@imladris.demon.co.uk> <1095337514.9144.2344.camel@imladris.demon.co.uk> : > On Thu, 16 Sep 2004, David Woodhouse wrote: > > > On Wed, 2004-09-15 at 16:26 -0700, Linus Torvalds wrote: > > > - if you want to go outside that bitwise type, you have to convert it > > > properly first. For example, if you want to add a constant to a > > > __le16 type, you can do so, but you have to use the proper sequence: > > > > > > __le16 sum, a, b; > > > > > > sum = a + b; /* INVALID! "warning: incompatible types for operation > > > (+)" */ sum = cpu_to_le16(le16_to_cpu(a) + le16_to_cpu(b)); /* Ok */ > > > > > > See? > > > > Yeah right, that latter case is _so_ much more readable > > It's not about readability. > > It's about the first case being WRONG! ... in general. And on the machines where it works (le machines), I'd certainly expect those conversion functions to be trivially eliminated by the compiler (ie, they're either trivial macros or trivial inline functions). > > I'd really quite like to see the real compiler know about endianness, > > too. Well, these day, optimizers often can recognize the usual endianness conversion idioms, so the compiler still gets a chance at inserting your load-with-swap or whatever. MfG Kai - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/