/usr/include/volk/volk_32u_popcnt.h is in libvolk1-dev 1.3-3.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 | /* -*- c++ -*- */
/*
* Copyright 2012, 2014 Free Software Foundation, Inc.
*
* This file is part of GNU Radio
*
* GNU Radio is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3, or (at your option)
* any later version.
*
* GNU Radio is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GNU Radio; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
/*!
* \page volk_32u_popcnt
*
* \b Overview
*
* Computes the population count (popcnt), or Hamming distance of a
* binary string. This kernel takes in a single unsigned 32-bit value
* and returns the count of 1's that the value contains.
*
* <b>Dispatcher Prototype</b>
* \code
* void volk_32u_popcnt(uint32_t* ret, const uint32_t value)
* \endcode
*
* \b Inputs
* \li value: The input value.
*
* \b Outputs
* \li ret: The return value containing the popcnt.
*
* \b Example
* \code
int N = 10;
unsigned int alignment = volk_get_alignment();
uint32_t bitstring = 0x55555555;
uint32_t hamming_distance = 0;
volk_32u_popcnt(&hamming_distance, bitstring);
printf("hamming distance of %x = %i\n", bitstring, hamming_distance);
* \endcode
*/
#ifndef INCLUDED_VOLK_32u_POPCNT_A16_H
#define INCLUDED_VOLK_32u_POPCNT_A16_H
#include <stdio.h>
#include <inttypes.h>
#ifdef LV_HAVE_GENERIC
static inline void
volk_32u_popcnt_generic(uint32_t* ret, const uint32_t value)
{
// This is faster than a lookup table
uint32_t retVal = value;
retVal = (retVal & 0x55555555) + (retVal >> 1 & 0x55555555);
retVal = (retVal & 0x33333333) + (retVal >> 2 & 0x33333333);
retVal = (retVal + (retVal >> 4)) & 0x0F0F0F0F;
retVal = (retVal + (retVal >> 8));
retVal = (retVal + (retVal >> 16)) & 0x0000003F;
*ret = retVal;
}
#endif /*LV_HAVE_GENERIC*/
#ifdef LV_HAVE_SSE4_2
#include <nmmintrin.h>
static inline void
volk_32u_popcnt_a_sse4_2(uint32_t* ret, const uint32_t value)
{
*ret = _mm_popcnt_u32(value);
}
#endif /*LV_HAVE_SSE4_2*/
#endif /*INCLUDED_VOLK_32u_POPCNT_A16_H*/
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