Subject: Re: [linux-audio-dev] swh plugins and fixing undenormalize
From: Jan Depner (eviltwin69_AT_cableone.net)
Date: Sat Jun 26 2004 - 01:38:24 EEST
On Fri, 2004-06-25 at 13:49, Tim Blechmann wrote:
> > I have a denormal fix without a branch but you probably don't want to
> > see it ;-)
> > It's pretty simple, just OR the bits of the exponent together which
> > gives either
> > 0 (denormal) or 1, typecast that to float, and then multiply the
> > original float by that (0.0 or 1.0). Voila, no branch, but it is
> > messy looking ;-)
>
> there is one problem ... if you multiply the denormal number with the 1
> or 0, you will probably have one denormal operation on the cpu instead
> of a branch ... i don't know, that's worse ...
> but definitely, some benchmarks would be useful for any denormal
> flushing algorithm...
>
The definition of denormal is that the exponent is 0 so you will never
multiply a denormal by 1, only by 0. I'm not sure whether that would be
a denormal operation or not. It depends on the compiler.
Jan