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From: Malcolm McLean <malcolm.arthur.mclean@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: Good hash for pointers
Date: Mon, 10 Jun 2024 01:34:21 +0100
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On 09/06/2024 12:35, Bonita Montero wrote:

> 
> uint64_t MichaelsHash( uint64_t key )
> {
>      __m128i xkey = _mm_set_epi64x( key, 42 );
>      using bar_t = pair<uint64_t, uint64_t>;
>      static bar_t const bars[8] =
>      {
>          { 0xBB09BBCC90B24BF2, 0x825C622FF2792A01 },
>          { 0x94F0535CB06D4060, 0x939C756246DBFD1D },
>          { 0x5B835E01A7E14CA1, 0xAC2BDAFC023CDD06 },
>          { 0xE0B6A4735B774AEC, 0x9CAFB43E7DDE494C },
>      };
>      for( bar_t const &bar : bars )
>          xkey = _mm_aesenc_si128( xkey, _mm_set_epi64x( bar.second, 
> bar.first ) );
>      return xkey.m128i_u64[0];
> }
> 
> Now the code is about six times faster and I get a eight times
> speedup over single-threaded processing with the same code. Of
> course the results are still the same.

Thank you.
I have your permission to drop that in?

-- 
Check out my hobby project.
http://malcolmmclean.github.io/babyxrc