Re: [patch 14/44] generic hweight{64,32,16,8}()
Ulrich Eckhardt <[email protected]>
| Newsgroups | gmane.linux.ports.sparc,gmane.linux.kernel,gmane.linux.ports.ia64,gmane.linux.ports.hppa,gmane.linux.ports.ppc.devel,gmane.linux.ports.sh.devel,gmane.linux.ports.ultrapenguin |
|---|---|
| Organization | Sator Laser GmbH |
| Message-ID | <[email protected]> |
On Wednesday 01 February 2006 10:02, Akinobu Mita wrote:
> unsigned int hweight32(unsigned int w);
> unsigned int hweight16(unsigned int w);
> unsigned int hweight8(unsigned int w);
> unsigned long hweight64(__u64 w);
IMHO, this should use explicitly sized integers like __u8, __u16 etc, unless
there are stringent reasons like better register use - which is hard to tell
for generic C code. Also, why on earth is the returntype for hweight64 a
long?
> +static inline unsigned int hweight32(unsigned int w)
> +{
> + unsigned int res = (w & 0x55555555) + ((w >> 1) & 0x55555555);
> + res = (res & 0x33333333) + ((res >> 2) & 0x33333333);
[...]
Why not use unsigned constants here?
> +static inline unsigned long hweight64(__u64 w)
> +{
[..]
> + u64 res;
> + res = (w & 0x5555555555555555ul) + ((w >> 1) & 0x5555555555555555ul);
Why not use initialisation here, too?
just my 2c
Uli
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