From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/4207 Path: news.gmane.org!not-for-mail From: Rich Felker Newsgroups: gmane.linux.lib.musl.general Subject: Re: Re: arm softfp compatibility arch/fpu in gcc-4.8.2 Date: Thu, 7 Nov 2013 18:16:26 -0500 Message-ID: <20131107231626.GX24286@brightrain.aerifal.cx> References: <527C126D.5000903@barfooze.de> <527C1842.1000300@barfooze.de> Reply-To: musl@lists.openwall.com NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-Trace: ger.gmane.org 1383866196 15430 80.91.229.3 (7 Nov 2013 23:16:36 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 7 Nov 2013 23:16:36 +0000 (UTC) Cc: David Wuertele To: musl@lists.openwall.com Original-X-From: musl-return-4211-gllmg-musl=m.gmane.org@lists.openwall.com Fri Nov 08 00:16:42 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 1VeYoZ-00063k-Ny for gllmg-musl@plane.gmane.org; Fri, 08 Nov 2013 00:16:39 +0100 Original-Received: (qmail 30615 invoked by uid 550); 7 Nov 2013 23:16:39 -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 30606 invoked from network); 7 Nov 2013 23:16:39 -0000 Content-Disposition: inline In-Reply-To: <527C1842.1000300@barfooze.de> User-Agent: Mutt/1.5.21 (2010-09-15) Xref: news.gmane.org gmane.linux.lib.musl.general:4207 Archived-At: On Thu, Nov 07, 2013 at 11:46:26PM +0100, John Spencer wrote: > >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). VFP is the only one which gives IEEE conforming behavior and the only one which is explicitly supported by musl (which requires/provides IEEE floating point semantics). Anything else might blow up (for example, crashing or wrong results in strtod or printf) so I would not recommend using them for compiling musl. If you want to use them in application code linked to musl (with the standard EABI, i.e. "arm") that doesn't depend on IEEE semantics, that shouldn't hurt anything. Fortunately, at least as I understand it, the other ARM fpu options were never widely available, and are pretty much deprecated. Rich