From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/4206 Path: news.gmane.org!not-for-mail From: John Spencer Newsgroups: gmane.linux.lib.musl.general Subject: Re: Re: arm softfp compatibility arch/fpu in gcc-4.8.2 Date: Thu, 07 Nov 2013 23:46:26 +0100 Message-ID: <527C1842.1000300@barfooze.de> References: <527C126D.5000903@barfooze.de> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1383864394 27436 80.91.229.3 (7 Nov 2013 22:46:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 7 Nov 2013 22:46:34 +0000 (UTC) Cc: musl@lists.openwall.com To: David Wuertele Original-X-From: musl-return-4210-gllmg-musl=m.gmane.org@lists.openwall.com Thu Nov 07 23:46:40 2013 Return-path: Envelope-to: gllmg-musl@plane.gmane.org Original-Received: from mother.openwall.net ([195.42.179.200]) by plane.gmane.org with smtp (Exim 4.69) (envelope-from ) id 1VeYLX-0002lD-GV for gllmg-musl@plane.gmane.org; Thu, 07 Nov 2013 23:46:39 +0100 Original-Received: (qmail 17496 invoked by uid 550); 7 Nov 2013 22:46:38 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: Original-Received: (qmail 17488 invoked from network); 7 Nov 2013 22:46:38 -0000 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:17.0) Gecko/20130801 Thunderbird/17.0.8 In-Reply-To: Xref: news.gmane.org gmane.linux.lib.musl.general:4206 Archived-At: David Wuertele wrote: > John Spencer barfooze.de> writes: > >>> arm-linux-musleabihf/4.8.2/../../../../arm-linux-musleabihf/bin/ld: failed to >>> merge target specific data of file lib/armeabi/libXXX.a(YYY.o) >>> >>> What arch/fpu should I use to build a toolchain that can link against this >>> library? >> if you need to link to proprietary softfloat modules, you have to use >> "softfp" float mode. that one is compatible to soft, but makes full use >> of the FPU. > > Thanks! That was what I was hoping. > > I see that gcc-4.8.2 supports "--with-float=softfp". I'm confused about what > to use for "--with-fpu", if anything. My choices are: > > | vfp | vfp3 | vfpv3 \ > | vfpv3-fp16 | vfpv3-d16 | vfpv3-d16-fp16 | vfpv3xd \ > | vfpv3xd-fp16 | neon | neon-fp16 | vfpv4 | vfpv4-d16 \ > | fpv4-sp-d16 | neon-vfpv4 | fp-arm-v8 | neon-fp-armv8 \ > | crypto-neon-fp-armv8) > > If I omit the "--with-fpu", will it just default to use soft float all the time? not sure what the default is, but afaik vfp is the most compatible one (only needed when you want to create binaries that work on way less decent arm chips). if you want the best speed, pick one of the neons - not sure which one your chip supports though. cortex A8 already supports neon, so that one should definitely work for you while giving decent performance. in doubt, ask your vendor for the best setting.