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Subject: Re: svn commit: r273274 - head/sys/netpfil/ipfw
From: David Chisnall <theraven@FreeBSD.org>
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To: Andriy Gapon <avg@FreeBSD.org>
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On 19 Oct 2014, at 13:02, Andriy Gapon <avg@FreeBSD.org> wrote:

> I think that on platforms where an optimized version of fls() is =
available that
> would work faster than this cool piece of bit magic.

If you're lucky, the compiler's idiom recogniser will spot this.  You're =
generally better off using the builtins though, because then the =
compiler will expand them to something sensible (hopefully - old =
versions of gcc did horribly inefficient things for bswap and clz on =
platforms without native support).

David