Messages in this thread | | | Subject | Re: [RFC][PATCH] Faster generic_fls | From | Falk Hueffner <> | Date | 30 Apr 2003 23:59:09 +0200 |
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Alan Cox <alan@lxorguk.ukuu.org.uk> 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.
-- Falk - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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