(Sorry, sending this again as I screwed up the previous mail).
Hi,
I have a question about fls64() which I hope you or someone else could
clarify, please see below.
On Sáb, 2008-03-15 at 18:32 +0100, Alexander van Heukelum wrote:
> +#elif BITS_PER_LONG == 64
> +static inline int fls64(__u64 x)
> +{
> + if (x == 0)
> + return 0;
> + return __fls(x) + 1;
> +}
It seems fls64() is implemented on top of __fls(), however the __fls()
implementation on the x86-64 architecture states that the result is
undefined if the argument does not have any zero bits.
So if I understand correctly, the statement "fls64(~0ULL)" would return
an undefined result on x64-64 instead of 64 as one would expect.
Wouldn't it make sense to check for ~0ULL in fls64()?
Thanks,
Ricardo
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