Comments on: Fast Integer Log2 function in C/C++ http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/ Casual Games Development Sat, 17 Dec 2011 06:31:08 +0000 http://wordpress.org/?v=2.9.2 hourly 1 By: Juan Pablo http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-8369 Juan Pablo Tue, 21 Jun 2011 12:01:11 +0000 http://www.southwindsgames.com/blog/?p=48#comment-8369 The one tagged: "Find the log base 2 of an N-bit integer in O(lg(N)) operations with multiply and lookup" is really smart, and it is easy to template the bounds for this one. Thanks for the sharing the link :) The one tagged: “Find the log base 2 of an N-bit integer in O(lg(N)) operations with multiply and lookup” is really smart, and it is easy to template the bounds for this one.
Thanks for the sharing the link :)

]]> By: GS http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-8366 GS Sun, 19 Jun 2011 18:54:47 +0000 http://www.southwindsgames.com/blog/?p=48#comment-8366 Faster implementations can be found at http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup. The lookup-table implementation is roughly a third faster than the fastest algorithm here, as I measured it. Faster implementations can be found at http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup. The lookup-table implementation is roughly a third faster than the fastest algorithm here, as I measured it.

]]> By: polar f4 http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-7827 polar f4 Sat, 29 Jan 2011 07:59:36 +0000 http://www.southwindsgames.com/blog/?p=48#comment-7827 What a great idea to let us in this whole procedure. What a great idea to let us in this whole procedure.

]]> By: Marcos http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-5964 Marcos Tue, 15 Jun 2010 17:59:13 +0000 http://www.southwindsgames.com/blog/?p=48#comment-5964 Thanks! Thanks!

]]> By: Joonas Kekoni http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-5032 Joonas Kekoni Fri, 12 Mar 2010 14:18:17 +0000 http://www.southwindsgames.com/blog/?p=48#comment-5032 Thanx. I was looking for this. Thanx. I was looking for this.

]]> By: Juan Pablo http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-4252 Juan Pablo Fri, 15 Jan 2010 11:51:37 +0000 http://www.southwindsgames.com/blog/?p=48#comment-4252 Yeah! My head is programmed to write multiplatform code but I should have mentioned it anyway since it is way easier and probably the way to go on intel machines. Thanks :) Yeah!
My head is programmed to write multiplatform code but I should have mentioned it anyway since it is way easier and probably the way to go on intel machines.
Thanks :)

]]> By: Eric Thiele http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-4251 Eric Thiele Fri, 15 Jan 2010 11:36:20 +0000 http://www.southwindsgames.com/blog/?p=48#comment-4251 on x86 arch you can do it event faster... bsr eax,eax input and output are the eax register bsr out,in (bit search reverse) searches the last enabeld bit in and writes position in out. (position last enabled bit ist the log2) :-) on x86 arch you can do it event faster…

bsr eax,eax

input and output are the eax register

bsr out,in (bit search reverse) searches the last enabeld bit in and writes position in out. (position last enabled bit ist the log2) :-)

]]> By: Juan Pablo http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-53 Juan Pablo Fri, 03 Apr 2009 11:21:58 +0000 http://www.southwindsgames.com/blog/?p=48#comment-53 You are right! Corrected, thanks! You are right!
Corrected, thanks!

]]> By: cristina http://www.southwindsgames.com/blog/2009/01/19/fast-integer-log2-function-in-cc/comment-page-1/#comment-52 cristina Fri, 03 Apr 2009 04:01:37 +0000 http://www.southwindsgames.com/blog/?p=48#comment-52 it is not equal or bigger. it is the last smaller or equal it is not equal or bigger.
it is the last smaller or equal

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