[lkml]   [2003]   [Apr]   [30]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC][PATCH] Faster generic_fls
Alan Cox <> writes:

> On Mer, 2003-04-30 at 17:16, Linus Torvalds wrote:
> > Clearly you're not going to make _one_ load to get fls, since having a
> > 4GB lookup array for a 32-bit fls would be "somewhat" wasteful.
> It ought to be basically the same as ffs because if I remember rightly
> ffs(x^(x-1)) == fls(x)

I don't think so. Maybe you are thinking of ffs(x) == fls(x & -x). So
you can calculate ffs with fls, but not easily the other way round.

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2005-03-22 13:35    [W:0.077 / U:11.348 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site