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exec: add tb_hash_func5, derived from xxhash

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This will be used by upcoming changes for hashing the tb hash.

Add this into a separate file to include the copyright notice from
xxhash.

Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1465412133-3029-7-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Emilio G. Cota 2016-06-08 14:55:24 -04:00 committed by Richard Henderson
parent ac9a9eba1e
commit dc8b295d05
1 changed files with 94 additions and 0 deletions
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include/exec/tb-hash-xx.h Normal file
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/*
* xxHash - Fast Hash algorithm
* Copyright (C) 2012-2016, Yann Collet
*
* BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php)
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* + Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* + Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* You can contact the author at :
* - xxHash source repository : https://github.com/Cyan4973/xxHash
*/
#ifndef EXEC_TB_HASH_XX
#define EXEC_TB_HASH_XX
#include <qemu/bitops.h>
#define PRIME32_1 2654435761U
#define PRIME32_2 2246822519U
#define PRIME32_3 3266489917U
#define PRIME32_4 668265263U
#define PRIME32_5 374761393U
#define TB_HASH_XX_SEED 1
/*
* xxhash32, customized for input variables that are not guaranteed to be
* contiguous in memory.
*/
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 >> 32;
uint32_t b = a0;
uint32_t c = b0 >> 32;
uint32_t d = b0;
uint32_t h32;
v1 += a * PRIME32_2;
v1 = rol32(v1, 13);
v1 *= PRIME32_1;
v2 += b * PRIME32_2;
v2 = rol32(v2, 13);
v2 *= PRIME32_1;
v3 += c * PRIME32_2;
v3 = rol32(v3, 13);
v3 *= PRIME32_1;
v4 += d * PRIME32_2;
v4 = rol32(v4, 13);
v4 *= PRIME32_1;
h32 = rol32(v1, 1) + rol32(v2, 7) + rol32(v3, 12) + rol32(v4, 18);
h32 += 20;
h32 += e * PRIME32_3;
h32 = rol32(h32, 17) * PRIME32_4;
h32 ^= h32 >> 15;
h32 *= PRIME32_2;
h32 ^= h32 >> 13;
h32 *= PRIME32_3;
h32 ^= h32 >> 16;
return h32;
}
#endif /* EXEC_TB_HASH_XX */