On Sat, Jun 4, 2011 at 7:14 PM, Benjamin Bellec <b.bel...@gmail.com> wrote: > Le 03/06/2011 06:09, Matt Turner a écrit : >> Also, if you want to check if the value is already a power-of-two, >> instead of a case statement for every POT (including 0), just do the >> standard is-power-of-two check: >> >> (x & (x - 1)) == 0 > > My own tests (on a Core2) shows that it's less efficient to do that, at > least with -O2 optimization enabled. With -O0, it's equal.
For what input set? Powers of two? Doesn't really matter, since the function isn't a hot path or anything, but I'd suppose that the Linux kernel has its is_power_of_2() function for a reason--that it's pretty ugly to have lots of case statements like powers of two. Matt _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
