From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from [66.111.4.26] (helo=out2.smtp.messagingengine.com) by linuxtogo.org with esmtp (Exim 4.69) (envelope-from ) id 1JcDrw-0002ld-I8 for openembedded-devel@lists.openembedded.org; Thu, 20 Mar 2008 07:03:18 +0100 Received: from compute1.internal (compute1.internal [10.202.2.41]) by out1.messagingengine.com (Postfix) with ESMTP id C54A8D84BB for ; Thu, 20 Mar 2008 02:03:15 -0400 (EDT) Received: from web7.messagingengine.com ([10.202.2.216]) by compute1.internal (MEProxy); Thu, 20 Mar 2008 02:03:15 -0400 Received: by web7.messagingengine.com (Postfix, from userid 99) id A26374E588; Thu, 20 Mar 2008 02:03:15 -0400 (EDT) Message-Id: <1205992995.25920.1243400709@webmail.messagingengine.com> X-Sasl-Enc: mx7rbDspxXerZl91ZJiXlIFjQeIMbwE/QH7RN/iePOv+ 1205992995 From: "Hasjim Williams" To: openembedded-devel@lists.openembedded.org MIME-Version: 1.0 X-Mailer: MessagingEngine.com Webmail Interface References: <1204494435.17068.23.camel@utx.utx.cz> In-Reply-To: Date: Thu, 20 Mar 2008 16:03:15 +1000 X-SA-Exim-Connect-IP: 66.111.4.26 X-SA-Exim-Mail-From: openembedded-devel@lists.futaris.org X-Spam-Checker-Version: SpamAssassin 3.2.3 (2007-08-08) on serenity X-Spam-Level: X-Spam-Status: No, score=0.1 required=5.0 tests=RDNS_NONE autolearn=no version=3.2.3 X-SA-Exim-Version: 4.2.1 (built Tue, 21 Aug 2007 23:39:36 +0000) X-SA-Exim-Scanned: Yes (on linuxtogo.org) Subject: Re: iwmmxt optimization and soft float in OE on PXA270 X-BeenThere: openembedded-devel@lists.openembedded.org X-Mailman-Version: 2.1.9 Precedence: list Reply-To: openembedded-devel@lists.openembedded.org List-Id: Using the OpenEmbedded metadata to build Distributions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 20 Mar 2008 06:03:19 -0000 Content-Disposition: inline Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="ISO-8859-1" On Mon, 03 Mar 2008 08:29:04 +0100, "Koen Kooi" said: > Stanislav Brabec schreef: > > | It should be the best possible optimization for PXA270 (compiled for > | iwmmxt, use soft float instead of exception based kernel driver, use > -Os > | to make binaries as small as possible and add optimizations from -O3). > > Angstrom already enables softfloat (for FPU-less systems) and -Os by > default *and* enables iwmmxt (if you have MACHINE_FEATURES = "iwmmxt") > for apps which have been proven to benefit from iwmmxt (e.g. mplayer). > > I still get mysterious segfaults when running an all iwmmxt glibc system > (uclibc is even worse), so I don't think flipping the global switch is a > good idea. You won't be able to use iwmmxt with everything. The unwind / exception support for iwxmmt isn't there in gcc. Anything using C++ exceptions won't work correctly. infocenter.arm.com/help/topic/com.arm.doc.ihi0038a/IHI0038A_ehabi.pdf explains about the unwind / exceptions. This is also one of the issues that Cirrus's MaverickCrunch currently has. The only ARM coprocessor that is fully supported (by gcc) is VFP. In summary, we'd have to modify: gcc/config/arm/pr-support.c gcc/config/arm/unwind-arm.h gcc/config/arm/unwind-arm.c for proper iwmmxt Unwind_VRS_Pop support. NB, I'm the guy that has done the MaverickCrunch gcc patches... I could write/test these patches, I guess, but the only PXA270 machine that I have access to is a HTC Magician (XDA Mini). Hasjim Williams