[FFmpeg-devel] Mixed data type in SIMD code?

[Michael Niedermayer]

On Mon, Mar 03, 2008 at 04:30:08PM -0700, Loren Merritt wrote:
> On Mon, 3 Mar 2008, Michael Niedermayer wrote:
> >
> > Also i doubt we use or ever will use packed double.
> 
> flac encoder does. Single isn't precise enough for a linear sum of up 
> to 16k elements. Reordering the sum to a tree made it half-way 
> decent decent precision, but also made it as slow as double.

What about something like:

for(i=0; i<16000;){
    float sum=0;
    do{
        sum+= whatever[i++];
    }while(i&127);
    double_sum += sum;
}

?

Or maybe even using int32_t ?

and no, ive not looked at the code ...

[...] 

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Those who are too smart to engage in politics are punished by being
governed by those who are dumber. -- Plato 
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