[FFmpeg-devel] [PATCH] configure+libm.h: add fmin/fmax/fminf/fmaxf emulation

[Michael Niedermayer]

On Sat, Oct 31, 2015 at 12:14:44AM +0100, Hendrik Leppkes wrote:
> On Fri, Oct 30, 2015 at 11:35 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > From: Michael Niedermayer <michael at niedermayer.cc>
> >
> > This should fix the build failure of avf_showcqt.c
> >
> > An alternative solution would be to add a check for fmin/fmax to fate-source and
> > then to replace them by FFMIN/FFMAX, i can do that if preferred?
> >
> > Untested due to lack of a affected platform
> >
> > Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
> > ---
> >  configure        |    8 ++++++++
> >  libavutil/libm.h |   28 ++++++++++++++++++++++++++++
> >  2 files changed, 36 insertions(+)
> >
> > diff --git a/configure b/configure
> > index 95790f4..e6f5d2c 100755
> > --- a/configure
> > +++ b/configure
> > @@ -1770,6 +1770,10 @@ MATH_FUNCS="
> >      exp2
> >      exp2f
> >      expf
> > +    fmax
> > +    fmaxf
> > +    fmin
> > +    fminf
> >      isinf
> >      isnan
> >      ldexpf
> > @@ -5304,6 +5308,10 @@ check_lib math.h sin -lm && LIBM="-lm"
> >  disabled crystalhd || check_lib libcrystalhd/libcrystalhd_if.h DtsCrystalHDVersion -lcrystalhd || disable crystalhd
> >
> >  atan2f_args=2
> > +fmax_args=2
> > +fmaxf_args=2
> > +fmin_args=2
> > +fminf_args=2
> >  copysign_args=2
> >  ldexpf_args=2
> >  powf_args=2
> > diff --git a/libavutil/libm.h b/libavutil/libm.h
> > index 6c17b28..ba837a2 100644
> > --- a/libavutil/libm.h
> > +++ b/libavutil/libm.h
> > @@ -43,6 +43,34 @@
> >  #define atan2f(y, x) ((float)atan2(y, x))
> >  #endif
> >
> > +#if !HAVE_FMAX
> > +#undef fmax
> > +static av_always_inline double fmax(double x, double y)
> > +{
> > +    if (x < y) return y;
> > +    else       return x;
> > +}
> > +#endif
> > +
> > +#if !HAVE_FMIN
> > +#undef fmin
> > +static av_always_inline double fmin(double x, double y)
> > +{
> > +    if (x < y) return x;
> > +    else       return y;
> > +}
> > +#endif
> 
> Wasn't there a concern that these emulations don't behave identical to
> the C library versions in regards to NaN handling?
> I faintly remember something in the previous discussion.

yes, i forgot about that :(
i replaced them by FFMIN / FFMAX

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are best at talking, realize last or never when they are wrong.
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