From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757564AbZHGL3f (ORCPT ); Fri, 7 Aug 2009 07:29:35 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757178AbZHGL3f (ORCPT ); Fri, 7 Aug 2009 07:29:35 -0400 Received: from crmm.lgl.lu ([158.64.72.228]:58126 "EHLO lll.lu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756081AbZHGL3e (ORCPT ); Fri, 7 Aug 2009 07:29:34 -0400 Message-ID: <4A7C1005.7010808@knaff.lu> Date: Fri, 07 Aug 2009 13:29:09 +0200 From: Alain Knaff User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1b3pre) Gecko/20090513 Fedora/3.0-2.3.beta2.fc11 Thunderbird/3.0b2 MIME-Version: 1.0 To: Albin Tonnerre CC: Russell King - ARM Linux , sam@ravnborg.org, hpa@zytor.com, linux-kernel@vger.kernel.org, linux-embedded@vger.kernel.org, akpm@linux-foundation.org Subject: Re: [PATCH 4/6] Add support for LZO-compressed kernels for ARM References: <20090731093107.GA29704@merkur.ravnborg.org> <1249311501-23102-1-git-send-email-albin.tonnerre@free-electrons.com> <1249311501-23102-2-git-send-email-albin.tonnerre@free-electrons.com> <1249311501-23102-3-git-send-email-albin.tonnerre@free-electrons.com> <1249311501-23102-4-git-send-email-albin.tonnerre@free-electrons.com> <20090806224055.GH31579@n2100.arm.linux.org.uk> <20090807092423.GA4455@laptop> <4A7BF5B8.4030907@knaff.lu> <20090807102117.GB4455@laptop> In-Reply-To: <20090807102117.GB4455@laptop> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/07/09 12:21, Albin Tonnerre wrote: > Indeed, they've not been applied. However, I'd rather try to understand why > exactly this is an issue when compiling with -Os and not -O2 instead of working > around it by removing the divisions. > > Regards, Well, I for myself couldn't get it to compile _at_all_ for ARM as long as there were any division operations in the code. My theory was that the ARM processor doesn't have native division, and that this is being supplied by some kind of run-time library, which is not linked with when building the pre-boot environment. But if it works with some compilation flags but not others, something more complex must be going on... ... or could it be that with some flags, the compiler generates "division emulation" code, but not with others (such as when optimizing for size?) Regards, Alain