Re: [RFC PATCH v1 0/3] Introducing ARM SIMD Support

Hi Vish,

I am very interested in your Vorbis optimisations.
Unfortunately I am not a NEON guru, nor even an ARM assembler one.
I had a quick look at your code and the only remark I have concerns the 
pseudo-code in comments.
In several places you write:
a[i] = a[i]*b[n-i-1] + a[i]*c[i]
but IMHO this should be:
a[i] = a[i]*b[n-i-1] + b[i]*c[i]

I have also done some work on Vorbis improvements, mainly to Tremor.
I posted some information on them to this list early this year, mainly 
in March.
Unfortunately nobody showed any interest in receiving patches :(
I shall be interested to see if anybody integrates yours.
Maybe we should be working on Opus ;-)

I am afraid that I have not tested your modifications.
For the moment I have been working on pure C code in the comfort of an 
x86_64 environment.
But I have oldish ARM hardware in mind as Tremor is really for 
architectures without hardware floating point.

Cheers,
Chris

Le 01/10/2014 20:33, Viswanath Puttagunta a écrit :
>
> On 1 October 2014 12:35, Ralph Giles <[email protected] 
> <mailto:[email protected]>> wrote:
>
>     On 2014-10-01 10:00 AM, Viswanath Puttagunta wrote:
>
>     > I would like to get feedback on "1" above from this list. I first
>     want
>     > to make sure the modifications to autoconf files is in line with the
>     > project.
>
>     Not having looked at the patches, you should compare your work
>     with the
>     instruction set detection in the opus implementation. That has worked
>     well so far, if you can say you did the same thing, it will be easier
>     for the authors to review it.
>
>     https://git.xiph.org/?p=opus.git;a=summary
>
> >> Thanks, will do.
>
>
>
>     > For "2", which is ARM NEON specific reviews, if necessary, I can
>     ping a
>     > few of ARM's NEON gurus and I think they will be happy to join
>     this list
>     > and review the code.
>
>     Do you have output verification and benchmark results you can share?
>
> >> As mentioned in cover letter for patches, available here 
> <https://docs.google.com/a/vishndivi.com/document/d/1LuMORT2jIroiuDKAQaj7YpizCRQBpgruC8DKDlzc8ik/edit>. 
>
>
>
>      -r
>
>
>
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> [email protected]
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