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

Michael Niedermayer michaelni
Fri Jun 1 03:55:02 CEST 2007


On Thu, May 31, 2007 at 05:30:16PM -0700, Trent Piepho wrote:
> > so i think you will agree with me that gcc does not gain any knowledge
> > of the read/written memory locatons by introducing extra operands in this
> > case ...
> >
> > and in the case that you agree we are back to the original:
> > current code (breaks old buggy apple assembler) vs. more operands which might
> And uses incorrect syntax.

maybe, its not overly relevant as we will likely not keep that code like
it is, but still iam curious, could you quote the part of the manual which
says its incorrect?

> > break with old gcc vs. writing the loop in asm which will be faster,
> > more compatible and wont depend on the moon phases when gcc was
> > released
> I think you'll find writing that loop in asm to not be so easy. 

> You'll
> need to have a lot of operands to the asm block, 

no, the 4 arguments passed to the function are sufficient
iam not saying it should be implemented like that iam just proofing
you wrong ...

> and that might break with
> old gcc. 

if (the false claim where true) yes

> And since it "might" break with old gcc it's impossible to do it.

no even if the above false claims where true this is not true
it would have to be tested like any other solution and if it works
there would be no problem, or are you arguing that the solution we
choose should not be tested?

anyway i dont understand why every thread in which you participate
degenerates into such trolling
may i suggest that you reread your replies and think about the 
correctness of your statements before hitting the send button?

so ive came up with the following decissions:
1. trent please stay out of disscussions related to gnu/elf/pic if you
   cannot accept that your views are not shared by the other people
2. the code should be changed so the loop statements are in asm and not
   in C this is the obvious optimal solution
3. as a temporary solution the SSE FFT can be disabled for mac osx
   or any other solution like the one proposed by trent can be commited
   but _before_ any solution is commited it should be benchmarked and
   tested with at least current gcc and gcc 2.95

Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Democracy is the form of government in which you can choose your dictator
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