On Sat, 10 Nov 2007 22:53:36 -0500 (EST) Robert P. J. Day wrote: > > Given a number of places in the tree that need to calculate this value > explicitly, might as well just create a macro for it. > > Signed-off-by: Robert P. J. Day <[EMAIL PROTECTED]> > > --- > > run-time tested for the first several values. note that this macro > is defined strictly in terms of rounding *up* -- i've seen no places > in the tree that require this expression to be rounded down, so i'm > not drawing that distinction. > > diff --git a/include/linux/log2.h b/include/linux/log2.h > index c8cf5e8..ed121c0 100644 > --- a/include/linux/log2.h > +++ b/include/linux/log2.h > @@ -190,4 +190,20 @@ unsigned long __rounddown_pow_of_two(unsigned long n) > __rounddown_pow_of_two(n) \ > ) > > +/** > + * order_base_2 - calculate the (rounded up) base 2 order of the argument > + * @n - parameter
* @n: argument (mostly changing - to :) > + * > + * The first few values calculated by this routine: > + * ob2(0) = 0 > + * ob2(1) = 0 > + * ob2(2) = 1 > + * ob2(3) = 2 > + * ob2(4) = 2 > + * ob2(5) = 3 > + * ... and so on. > + */ > + > +#define order_base_2(n) ilog2(roundup_pow_of_two(n)) > + > #endif /* _LINUX_LOG2_H */ > > -- --- ~Randy - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
