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

[Gerhard Roethlin]

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.

> but i cant find the right ASM function for this problem.
> 
> compiling line was:
> ./configure \
> --target-os=darwin \
> --cc=/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc-4.2  \
> --as="gas-preprocessor.pl /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/llvm-gcc-4.2" \
> --sysroot=/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.0.sdk \
> --extra-cflags="-w -arch armv7 -mfpu=neon " \
> --extra-ldflags="-arch armv7 -mfpu=neon -isysroot /Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS5.0.sdk" \
> --arch=arm \
> --cpu=cortex-a8 \
> --extra-cflags='-arch armv7' \
> --extra-ldflags='-arch armv7' \
> --prefix=compiled/armv7 \
> --disable-ffmpeg \
> --disable-ffplay \
> --disable-ffprobe \
> --disable-ffserver \
> --disable-avdevice \
> --disable-bzlib \
> --disable-mmx \
> --disable-encoders \
> --enable-cross-compile \
> --enable-pic
> make

I use default values for cc, and a set of scripts for easier building:
https://github.com/cbreak-black/ffmpeg-ios-build
(It creates fat binaries for the simulator and the old/new iThings)

> Anyone can help me, maybe with paid support?
> 
> gary
> 
> 
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> ffmpeg-devel at ffmpeg.org
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Gerhard Röthlin
Tech Transfer & Git Mastery