Date: Sun, 19 Oct 2014 15:02:07 +0300 From: Andriy Gapon <avg@FreeBSD.org> To: "Alexander V. Chernikov" <melifaro@FreeBSD.org>, src-committers@FreeBSD.org, svn-src-all@FreeBSD.org, svn-src-head@FreeBSD.org Subject: Re: svn commit: r273274 - head/sys/netpfil/ipfw Message-ID: <5443A83F.5090807@FreeBSD.org> In-Reply-To: <201410191115.s9JBFJxA058370@svn.freebsd.org> References: <201410191115.s9JBFJxA058370@svn.freebsd.org>
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On 19/10/2014 14:15, Alexander V. Chernikov wrote:
> +static uint32_t
> +roundup2p(uint32_t v)
> +{
> +
> + v--;
> + v |= v >> 1;
> + v |= v >> 2;
> + v |= v >> 4;
> + v |= v >> 8;
> + v |= v >> 16;
> + v++;
> +
> + return (v);
> +}
I think that on platforms where an optimized version of fls() is available that
would work faster than this cool piece of bit magic.
--
Andriy Gapon
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