From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ludovic Desroches Date: Thu, 01 Mar 2012 09:09:25 +0100 Subject: [Buildroot] Question about float-abi In-Reply-To: <20120229154710.7729776d@skate> References: <20120228105550.GM23707@ldesroches-Latitude-E6320> <20120229110850.GN23707@ldesroches-Latitude-E6320> <20120229134909.GO23707@ldesroches-Latitude-E6320> <20120229154710.7729776d@skate> Message-ID: <4F4F2EB5.3010709@atmel.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Hello Thomas, On 02/29/2012 03:47 PM, Thomas Petazzoni wrote: > Hello Ludovic, > > Le Wed, 29 Feb 2012 14:49:09 +0100, > Ludovic Desroches a ?crit : > >> Yes there were missing options for gcc: --with-float=hard and >> --with-fpu=... >> >> Now floating score is correct. I am surprised by the good results of >> the uclibc. I don't know if nbench is an accurate benchmark to test >> several libc but scores obtained by glibc, eglibc and uclibc are very >> closed. > As I told you on IRC, those investigations are really interesting. We > know that the Buildroot support for floating-point is far from perfect, > this has been briefly discussed during the last Buildroot Developer > meeting. If you want to improve this part of Buildroot, do not hesitate > to send patches, we are definitely interested. > > I guess with internal toolchains, it's quite easy to improve things. > The case of external toolchains is probably a bit more complicated, > since we do not control how the C library of the external toolchain has > been built in terms of floating point support. > I agree using external toolchain even those generated by crosstool-ng can be a little more complicated. I was mostly worried about reproducibility since I had some troubles to generate my toolchain with crosstool-ng: the version of some packages were not compatible, I need specific package version on host side, etc. Crosstool-ng is a great tool to tune your toolchain and show me missing options into Buildroot to support hard floating point. Buildroot allows me to do what I want so it's good for me. The only thing I can 'criticize' is that some options like BR2_VFP_FLOAT seem to enable the hardware floating point support but in fact no, we need to set extra settings. I will try to give you extra feedbacks and to send some patches. Regards Ludovic