[FFmpeg-devel] [RFC] insufficient VFP check?
Sun Jan 17 01:07:05 CET 2010
On Sun, Jan 17, 2010 at 02:03:32AM +0200, Siarhei Siamashka wrote:
> On Sunday 17 January 2010, Reimar D?ffinger wrote:
> > On Sat, Jan 16, 2010 at 11:40:34PM +0000, M?ns Rullg?rd wrote:
> > > Reimar D?ffinger <Reimar.Doeffinger at gmx.de> writes:
> > > > Hello,
> > > > the configure vfp check looks for
> > > > fadds s0, s0, s0
> > > > However, this detects VFP e.g. for
> > > > -mcpu=cortex-a8 -mfpu=neon -mfloat-abi=softfp
> > > > while actual compilation fails with e.g.
> > > > libavcodec/arm/dsputil_vfp.S:160: Error: selected processor does not
> > > > support `vmov r7,r8,s4,s5' So what is the right solution, replace the
> > > > check with something like the failing instruction?
> > >
> > > What configure line did you use? It always works for me...
> > Something a bit silly:
> > ./configure --cross-prefix=armv7a-softfloat-linux-gnueabi-
> > --extra-cflags="-mcpu=cortex-a8 -mfpu=neon -mfloat-abi=softfp" --arch=arm
> > --cpu=cortex-a8 However doesn't look silly enough to make it break that
> > way..
> At least gentoo has problems compiling mplayer/ffmpeg with
> armv7a-softfloat-linux-gnueabi toolchain (because it has an extra softfloat
> related patch applied by ebuild), armv7a-unknown-linux-gnueabi is fine.
Uh, can the -unknown- variant compile vfp/neon?
I came to the conclusion, idiotic as it is (not commenting on the technical
point, but from a usability one), that softfloat is necessary
to have neon/vfp support.
More information about the ffmpeg-devel