[FFmpeg-devel] [PATCH]replace movw instruction in ac3dsp_armv6.S

[Aurelien Jacobs]

On Sat, Apr 09, 2011 at 04:05:11PM +0800, pin xue wrote:
> AS      libavcodec/arm/ac3dsp_armv6.o
> ffmpeg-src/libavcodec/arm/ac3dsp_armv6.S: Assembler messages:
> ffmpeg-src/libavcodec/arm/ac3dsp_armv6.S:40: Error: selected processor
> does not support `movw r8,#0x1fe0'
> make[1]: *** [libavcodec/arm/ac3dsp_armv6.o] Error 1
> 
> MOVW is ARMv7 way to load constant:

IIUC this doesn't require ARMv7. This is available since ARMv6T2.
But this is not available on strict ARMv6.

> But here it is armv6 optimization, so that we have to use ldr.

Indeed.

To get the best of target architecture, you may want to use movw
#if HAVE_ARMV6T2 and use ldr #else.

Aurel