[FFmpeg-devel] compile for arm cortex A8 with iOS SDK 5

[Michael Niedermayer]

On Tue, Jan 17, 2012 at 08:59:34AM +0100, Gerhard Roethlin wrote:
> I had similar problems
> 
> On 2012.01.09, at 21:08, gary wrote:
> 
> > iam using ffmpeg-HEAD-f247f4c with llvm-gcc.4.2 compiler. 
> > 
> > when i activate the ASM neon support iam hanging right now at some instructions.
> > 
> > i tried a first fix in the libavutil.h
> > 
> > intmath.h
> > 
> > #define av_clipl_int32 av_clipl_int32_arm
> > static av_always_inline av_const int32_t av_clipl_int32_arm(int64_t a)
> > {
> >    int x, y;
> >    __asm__ (//"adds   %1, %R2, %Q2, lsr #31  \n\t"
> >             "itet   ne                     \n\t"
> >             "mvnne  %1, #1<<31             \n\t"
> >             //"moveq  %0, %Q2                \n\t"
> >             //"eorne  %0, %1,  %R2, asr #31  \n\t"
> >             : "=r"(x), "=&r"(y) : "r"(a):"cc");
> >    return x;
> > }
> 
> My solution for that was to make the av_clip macro only get used with gcc 4.4 or newer
> 
> > now i have another problem in 
> > CC	libavformat/asf.o
> > CC	libavformat/asfcrypt.o
> > error: invalid operand in inline asm: 'ldr   ${0:Q}, $1  
> > 	ldr   ${0:R}, $2  
> > 	'
> 
> Maybe AV_RN64. I fixed both problems in the patch I submitted a month ago:
> http://ffmpeg.org/pipermail/ffmpeg-devel/2011-December/117848.html
> 
> But it's not much of a fix, more just ignoring the problem.

If someone finds a fix i would be very interrested to have that in
main git.
simply disabling for gcc before 4.4 is of course ok too when versions
prior to that really cant handle it.

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

Rewriting code that is poorly written but fully understood is good.
Rewriting code that one doesnt understand is a sign that one is less smart
then the original author, trying to rewrite it will not make it better.
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