[FFmpeg-devel] [PATCH] Faster ff_sqrt()

[John Kelley]

On 1/13/08, Reimar D?ffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de> wrote:
> Hello,
> On Sun, Jan 13, 2008 at 08:49:17PM +0100, Michael Niedermayer wrote:
> [...]
> > noone? well heres a simpler variant, though possibly slower (didnt benchmark)
>
> Well, you are at least too fast for us, I got about as far as thinking
> if av_log2 >> 1 couldn't give a better starting-point (well I am doing
> all kinds of other things at the same time after all) :-)
>
> Greetings,
> Reimar D?ffinger

I know we're talking about sqrt and not inverse sqrt but this made me
think of the InvSqrt from Quake III. History here:
http://www.beyond3d.com/content/articles/8/

Cheers,
John