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https://github.com/VectorCamp/vectorscan.git
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78 lines
2.9 KiB
C
78 lines
2.9 KiB
C
/*
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* Copyright (c) 2015-2017, Intel Corporation
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* Copyright (c) 2020-2021, VectorCamp PC
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* * Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* * Neither the name of Intel Corporation nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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/** \file
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* \brief Platform specific popcount functions
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*/
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#ifndef UTIL_POPCOUNT_H_
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#define UTIL_POPCOUNT_H_
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#include "ue2common.h"
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#include "util/arch.h"
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static really_inline
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u32 popcount32(u32 x) {
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return __builtin_popcount(x);
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// #if defined(HAVE_POPCOUNT_INSTR)
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// // Single-instruction builtin.
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// return _mm_popcnt_u32(x);
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// #else
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// // Fast branch-free version from bit-twiddling hacks as older Intel
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// // processors do not have a POPCNT instruction.
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// x -= (x >> 1) & 0x55555555;
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// x = (x & 0x33333333) + ((x >> 2) & 0x33333333);
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// return (((x + (x >> 4)) & 0xf0f0f0f) * 0x1010101) >> 24;
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// #endif
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}
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static really_inline
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u32 popcount64(u64a x) {
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return __builtin_popcountll(x);
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// #if defined(ARCH_X86_64)
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// # if defined(HAVE_POPCOUNT_INSTR)
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// // Single-instruction builtin.
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// return (u32)_mm_popcnt_u64(x);
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// # else
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// // Fast branch-free version from bit-twiddling hacks as older Intel
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// // processors do not have a POPCNT instruction.
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// x -= (x >> 1) & 0x5555555555555555;
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// x = (x & 0x3333333333333333) + ((x >> 2) & 0x3333333333333333);
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// x = (x + (x >> 4)) & 0x0f0f0f0f0f0f0f0f;
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// return (x * 0x0101010101010101) >> 56;
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// # endif
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// #else
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// // Synthesise from two 32-bit cases.
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// return popcount32(x >> 32) + popcount32(x);
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// #endif
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}
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#endif /* UTIL_POPCOUNT_H_ */
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