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https://github.com/VectorCamp/vectorscan.git
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92 lines
3.0 KiB
C
92 lines
3.0 KiB
C
/*
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* Copyright (c) 2015, Intel Corporation
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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 Naive dynamic shuffles.
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*
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* These are written with the assumption that the provided masks are sparsely
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* populated and never contain more than 32 on bits. Other implementations will
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* be faster and actually correct if these assumptions don't hold true.
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*/
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#ifndef SHUFFLE_H
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#define SHUFFLE_H
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#include "config.h"
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#include "bitutils.h"
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#include "simd_utils.h"
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#include "ue2common.h"
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#if defined(__BMI2__) || (defined(_WIN32) && defined(__AVX2__))
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#define HAVE_PEXT
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#endif
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static really_inline
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u32 shuffleDynamic32(u32 x, u32 mask) {
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#if defined(HAVE_PEXT)
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// Intel BMI2 can do this operation in one instruction.
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return _pext_u32(x, mask);
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#else
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u32 result = 0, num = 1;
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while (mask != 0) {
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u32 bit = findAndClearLSB_32(&mask);
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if (x & (1U << bit)) {
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assert(num != 0); // more than 32 bits!
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result |= num;
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}
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num <<= 1;
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}
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return result;
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#endif
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}
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static really_inline
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u32 shuffleDynamic64(u64a x, u64a mask) {
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#if defined(HAVE_PEXT) && defined(ARCH_64_BIT)
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// Intel BMI2 can do this operation in one instruction.
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return _pext_u64(x, mask);
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#else
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u32 result = 0, num = 1;
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while (mask != 0) {
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u32 bit = findAndClearLSB_64(&mask);
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if (x & (1ULL << bit)) {
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assert(num != 0); // more than 32 bits!
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result |= num;
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}
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num <<= 1;
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}
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return result;
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#endif
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}
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#undef HAVE_PEXT
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#endif // SHUFFLE_H
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