Re: [PATCH 00/17] Introduce and use generic parity32/64 helper

Jeremy Kerr <[email protected]>
Newsgroups dev.linux.lists.brcm80211,org.freedesktop.lists.dri-devel,org.infradead.lists.linux-mtd,org.kernel.vger.bpf,org.kernel.vger.linux-input,org.kernel.vger.linux-kernel,org.kernel.vger.linux-media,org.kernel.vger.linux-serial,org.kernel.vger.linux-wireless,org.kernel.vger.netdev
Message-ID <[email protected]> 
Hi Kuan-Wei,

> Several parts of the kernel contain redundant implementations of parity
> calculations for 32-bit and 64-bit values. Introduces generic
> parity32() and parity64() helpers in bitops.h, providing a standardized
> and optimized implementation.  

More so than __builtin_parity() ?

I'm all for reducing the duplication, but the compiler may well have a
better parity approach than the xor-folding implementation here. Looks
like we can get this to two instructions on powerpc64, for example.

Cheers,


Jeremy
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