[linux-audio-dev] Fixed vs Floating point comparison.

[Juan Linietsky]

On Friday 17 October 2003 01:20, Steve Harris wrote:
> On Thu, Oct 16, 2003 at 08:09:13 -0300, Juan Linietsky wrote:
> > My own conclusions about the subject is that the float -> int conversion
> > is STILL the biggest bottleneck on most common architectures. And until
> > this is sorted out, fixed point is still the best solution for some
> > specific cases,
>
> How are you doing the conversion, casts are horribly slow, but lrintf()
> etc. are quite fast (a few cycles).
>

There's 2 ways, if you check the benchmarks, the ones that say "float"
use a cast, and the ones that say "fistl" use that instruction (which is 
faster in most cases). I think what surprised me the most about all this
is the slow performance of the G4 on floating point.. I heard several times
that they have instant float->int conversion... and this is using apple's gcc 
compiler.


Juan Linietsky