[MPlayer-dev-eng] ARM and liba52

[Diego Biurrun]

On Thu, May 01, 2008 at 01:05:40PM +0300, Siarhei Siamashka wrote:
> On Monday 28 April 2008, Siarhei Siamashka wrote:
> >
> > Currently liba52 is broken for ARM processors which require strict
> > alignment for accessing memory (ARM9, XScale, ...). AC3 audio playback just
> > produces noise.
> >
> > Interestingly enough, the problem was introduced in 2003 (SVN revision
> > 10314), and it was supposedly a fix for ARM:
> > http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2003-June/019377.html
> >
> > I wonder if it was a fix that turned compilation error into runtime failure
> > ;)
> >
> > Anyway, it should be mentioned that modern ARM cores (such as ARM11)
> > support unaligned memory access natively. Older cores can emulate unaligned
> > memory accesses by handling alignment faults in the kernel, but this is
> > very slow.
> >
> > PS. liba52 uses floating point math which is very slow on old ARM cores
> > without hardware FPU, so using liba52 on such old cores is not very
> > practical anyway.
> 
> Ping.
> 
> Can anybody consider reverting r10314 change? Or alternatively you can try to
> use the attached patch. Anyway, some kind of action needs to be taken to fix
> this breakage.

Patch applied, thanks.

Diego