[opus] [Opus] [Patch]01-Add ARM5E macros

[Peter Robinson]

On Mon, May 20, 2013 at 4:21 AM, Timothy B. Terriberry
<tterribe at xiph.org> wrote:
> Timothy B. Terriberry wrote:
>> Aurélien Zanelli wrote:
>>> Also, if you have any question or comment about it, feel free to contact
>>> me.
>>
>> A lot of these macros consist of a single ARM instruction, yet specify
>> an early clobber constraint for the output. Is that intentional?
>
> Apparently it was Jean-Marc who added those constraints in the original
> file in libspeex (though he couldn't remember why). In any case, I
> committed a modified version of your patch:
>
> https://git.xiph.org/?p=opus.git;a=commitdiff;h=972a34ec
>
> Total speed up was 22.3% on test_opus_encoder on a 600 MHz Cortex A8
> using gcc 4.2.1 (there are probably more representative tests and
> certainly better compilers, but that should give an idea of the ballpark).

Is this run time fast path detected or compile time tested? For
generic distros like Fedora the later would be preferable because the
HW it's compiled on is unlikely to be the same as it's running on.
ARMv7 and NEON optimisations would be cool too.

Peter