From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Thu, 11 Sep 2014 22:57:15 +0200 Subject: [Buildroot] [PATCH 1/2] powerpc/spe: tweak glibc/eglibc/uclibc combinations In-Reply-To: <1410436592-1990-1-git-send-email-gustavo@zacarias.com.ar> References: <1410436592-1990-1-git-send-email-gustavo@zacarias.com.ar> Message-ID: <20140911225715.70f88987@free-electrons.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Dear Gustavo Zacarias, On Thu, 11 Sep 2014 08:56:31 -0300, Gustavo Zacarias wrote: > Since (e)glibc 2.19+ PowerPC SPE changed ABI conventions for sanity. > In the good old days hard-float was used, it sounds good on paper until > you account for the e500v1/v2 differences, with v1 being a fpu that does > only single-precision math. > > So the ABI changed to make it soft-float and the libc (or libm) handle > that deficiency in software if required, making old precompiled binaries > incompatible (of no concern for buildroot since we've got no precompiled > binary blobs for SPE in packages). I'm not sure to fully understand: is PowerPC really using *soft-float* as in all floating point operations are emulated in software? Or is it a difference similar to the difference between hardfp and softfp on ARM (both use the FPU and floating point instructions, it's only a different ABI, where hardfp passes floating point arguments in floating point registers, while softfp passes floating point arguments in integer registers). Thanks, Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com