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Date: Tue, 17 May 2016 15:48:34 -0400
From: "Emilio G. Cota" <cota@braap.org>
Message-ID: <20160517194834.GC30174@flamenco>
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Subject: Re: [Qemu-devel] [PATCH v5 08/18] exec: add tb_hash_func5,
 derived from xxhash
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To: Sergey Fedorov <serge.fdrv@gmail.com>
Cc: QEMU Developers <qemu-devel@nongnu.org>, MTTCG Devel <mttcg@listserver.greensocs.com>, Alex =?iso-8859-1?Q?Benn=E9e?= <alex.bennee@linaro.org>, Paolo Bonzini <pbonzini@redhat.com>, Peter Crosthwaite <crosthwaite.peter@gmail.com>, Richard Henderson <rth@twiddle.net>

On Tue, May 17, 2016 at 20:22:52 +0300, Sergey Fedorov wrote:
> On 14/05/16 06:34, Emilio G. Cota wrote:
(snip)
> > +static inline
> > +uint32_t tb_hash_func5(uint64_t a0, uint64_t b0, uint32_t e)
> > +{
> > +    uint32_t v1 = TB_HASH_XX_SEED + PRIME32_1 + PRIME32_2;
> > +    uint32_t v2 = TB_HASH_XX_SEED + PRIME32_2;
> > +    uint32_t v3 = TB_HASH_XX_SEED + 0;
> > +    uint32_t v4 = TB_HASH_XX_SEED - PRIME32_1;
> > +    uint32_t a = a0 >> 31 >> 1;
> 
> I'm wondering if there's something special forcing us to make ">> 31
> >>1" instead of just ">> 32" on uint64_t?

Not really; it's perfectly fine to do >> 32 since both a0 and b0
are u64's.

I've changed it in my tree, thanks.

		Emilio