Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759073AbXLUMYj (ORCPT ); Fri, 21 Dec 2007 07:24:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751476AbXLUMYb (ORCPT ); Fri, 21 Dec 2007 07:24:31 -0500 Received: from anchor-post-36.mail.demon.net ([194.217.242.86]:1392 "EHLO anchor-post-36.mail.demon.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750918AbXLUMYa (ORCPT ); Fri, 21 Dec 2007 07:24:30 -0500 X-Greylist: delayed 933 seconds by postgrey-1.27 at vger.kernel.org; Fri, 21 Dec 2007 07:24:30 EST Message-ID: <476BACD6.5060900@superbug.co.uk> Date: Fri, 21 Dec 2007 12:08:54 +0000 From: James Courtier-Dutton User-Agent: Thunderbird 2.0.0.6 (Windows/20070728) MIME-Version: 1.0 To: =?ISO-8859-1?Q?=22J=2EA=2E_Magall=F3n=22?= CC: "linux-os (Dick Johnson)" , Linux kernel Subject: Re: Trying to convert old modules to newer kernels References: <20071219202323.GH2310@csclub.uwaterloo.ca> <20071220150255.GE2308@csclub.uwaterloo.ca> <20071220182815.GA5438@uranus.ravnborg.org> <20071220220547.GA5641@uranus.ravnborg.org> <20071221005303.771032f3@werewolf> In-Reply-To: <20071221005303.771032f3@werewolf> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1444 Lines: 35 J.A. Magall?n wrote: >>>> >>>> I need to get rid of -mregparm=3 on gcc's command line. It >>>> is completely incompatible with the standard calling conventions >>>> used in all our assembly-language files in our drivers. We make >>>> very high-speed number-crunching drivers that munge high-speed >>>> data into images. We need to do that in assembly as we have >>>> always done. >>>> > > Just for curiosity... yep, I understand now you have everything written > in assembler, but why not consider start writing it in C and stop > doing the compiler work (such as pipelining, out of order reordering, > loop unrolling for specific processor, and so on...) > > That's what everyone taught me, nowadays you won't be better than the > compiler in anything longer than three lines... > > Not true for image processing. compilers are not too good with optimizing mmx and sse algorithms. This is why user space libraries like ffmpeg still use assembly code. That being said, I don't think sse and mmx are available in kernel space, so I would have suggested doing all the grunt work in userspace would be better for this persons application so that he could use sse and mmx etc. James -- 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/