Date: Sun, 22 Aug 1999 01:01:57 -0700 From: John-Mark Gurney <gurney_j@efn.org> To: Mark Murray <mark@grondar.za> Cc: Nick Hibma <hibma@skylink.it>, FreeBSD Hackers mailing list <hackers@FreeBSD.ORG> Subject: Re: from number to power of two Message-ID: <19990822010157.02195@hydrogen.fircrest.net> In-Reply-To: <199908220750.JAA69064@gratis.grondar.za>; from Mark Murray on Sun, Aug 22, 1999 at 09:50:12AM %2B0200 References: <199908220750.JAA69064@gratis.grondar.za>
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Mark Murray scribbled this message on Aug 22: > > Does anyone know an inexpensive algorithm (O(1)) to go from an number to > > the next (lower or higher) power of two. > > > > 1 -> 1 > > 2,3 -> 2 > > 4,5,6,7 -> 4 > > 8,9,10,11,12,13,14,15 -> 8 > > etc. > > > > So %1101 should become either %10000 or %1000. > > Shift a bit until it becomes greater than (or less than) the number > in question. ummm, didn't you read his post?? he wanted a O(1) routine, NOT a O(n) routine... -- John-Mark Gurney Voice: +1 541 684 8449 Cu Networking P.O. Box 5693, 97405 "The soul contains in itself the event that shall presently befall it. The event is only the actualizing of its thought." -- Ralph Waldo Emerson To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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