[FFmpeg-devel] r9017 breaks WMA decoding on Intel Macs

Michael Niedermayer michaelni
Tue May 29 16:30:35 CEST 2007


On Tue, May 29, 2007 at 03:13:16PM +0200, Guillaume Poirier wrote:
> Hi,
> Le 29 mai 07 ? 11:58, Guillaume POIRIER a ?crit :
> >On 5/29/07, Zuxy Meng <zuxy.meng at gmail.com> wrote:
> >>2007/5/29, Guillaume Poirier <gpoirier at mplayerhq.hu>:
> >>>Le 28 mai 07 ? 01:26, Trent Piepho a ?crit :
> >>>
> >>>>On Mon, 28 May 2007, Guillaume POIRIER wrote:
> >>>>>On 5/28/07, Trent Piepho <xyzzy at speakeasy.org> wrote:
> >>>>I'm attaching a patch showing the right way to do.
> >>>
> >>>Ok, I get the idea. Inline asm is pretty much black magic to me.
> >>>
> >>>Your patch doesn't work, as it doesn't even assemble, but attached
> >>>corrected patch does fix the problem.
> >>>
> >>>Zuxy, Michael, what do you think about it?
> >>>Note that I did try to putting all asm blocks of fft_sse.c as "asm
> >>>volatile" but that didn't fix the problem alone.
> >>
> >>It looks good to me, but is the "asm" -> "asm volatile" part
> >>absolutely necessary?
> >
> >Don't know. This sure can be tested. I'd like to point out that every
> >ASM block in lavc is declared as "asm volatile", except in fft_sse.c.
> >Why is that? Why would you want them to be left as non-volatile?
> >
> >Won't GCC try to outsmart us sooner or later and break your beautiful
> >little ASM blocks? ;-)
> Ok, I just tested it: adding "volatile" keyword doesn't help fixing  
> the bug, so I removed it, hence attached patch.

id like to understand precissely what caused the problem and how before
some patch is applied

someonw should use gcc -S and gdb to look at what gets
misscompiled/missassembled exactly

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Why not whip the teacher when the pupil misbehaves? -- Diogenes of Sinope
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