volk_32f_s32f_stddev_32f.h

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/* -*- c++ -*- */
/*
 * Copyright 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.
 */

#ifndef INCLUDED_volk_32f_s32f_stddev_32f_a_H
#define INCLUDED_volk_32f_s32f_stddev_32f_a_H

#include <volk/volk_common.h>
#include <inttypes.h>
#include <stdio.h>
#include <math.h>

#ifdef LV_HAVE_SSE4_1
#include <smmintrin.h>
/*!
  \brief Calculates the standard deviation of the input buffer using the supplied mean
  \param stddev The calculated standard deviation
  \param inputBuffer The buffer of points to calculate the std deviation for
  \param mean The mean of the input buffer
  \param num_points The number of values in input buffer to used in the stddev calculation
*/
static inline void volk_32f_s32f_stddev_32f_a_sse4_1(float* stddev, const float* inputBuffer, const float mean, unsigned int num_points){
  float returnValue = 0;
  if(num_points > 0){
    unsigned int number = 0;
    const unsigned int sixteenthPoints = num_points / 16;

    const float* aPtr = inputBuffer;

    __VOLK_ATTR_ALIGNED(16) float squareBuffer[4];

    __m128 squareAccumulator = _mm_setzero_ps();
    __m128 aVal1, aVal2, aVal3, aVal4;
    __m128 cVal1, cVal2, cVal3, cVal4;
    for(;number < sixteenthPoints; number++) {
      aVal1 = _mm_load_ps(aPtr); aPtr += 4;
      cVal1 = _mm_dp_ps(aVal1, aVal1, 0xF1);

      aVal2 = _mm_load_ps(aPtr); aPtr += 4;
      cVal2 = _mm_dp_ps(aVal2, aVal2, 0xF2);

      aVal3 = _mm_load_ps(aPtr); aPtr += 4;
      cVal3 = _mm_dp_ps(aVal3, aVal3, 0xF4);

      aVal4 = _mm_load_ps(aPtr); aPtr += 4;
      cVal4 = _mm_dp_ps(aVal4, aVal4, 0xF8);

      cVal1 = _mm_or_ps(cVal1, cVal2);
      cVal3 = _mm_or_ps(cVal3, cVal4);
      cVal1 = _mm_or_ps(cVal1, cVal3);

      squareAccumulator = _mm_add_ps(squareAccumulator, cVal1); // squareAccumulator += x^2
    }
    _mm_store_ps(squareBuffer,squareAccumulator); // Store the results back into the C container
    returnValue = squareBuffer[0];
    returnValue += squareBuffer[1];
    returnValue += squareBuffer[2];
    returnValue += squareBuffer[3];

    number = sixteenthPoints * 16;
    for(;number < num_points; number++){
      returnValue += (*aPtr) * (*aPtr);
      aPtr++;
    }
    returnValue /= num_points;
    returnValue -= (mean * mean);
    returnValue = sqrtf(returnValue);
  }
  *stddev = returnValue;
}
#endif /* LV_HAVE_SSE4_1 */

#ifdef LV_HAVE_SSE
#include <xmmintrin.h>
/*!
  \brief Calculates the standard deviation of the input buffer using the supplied mean
  \param stddev The calculated standard deviation
  \param inputBuffer The buffer of points to calculate the std deviation for
  \param mean The mean of the input buffer
  \param num_points The number of values in input buffer to used in the stddev calculation
*/
static inline void volk_32f_s32f_stddev_32f_a_sse(float* stddev, const float* inputBuffer, const float mean, unsigned int num_points){
  float returnValue = 0;
  if(num_points > 0){
    unsigned int number = 0;
    const unsigned int quarterPoints = num_points / 4;

    const float* aPtr = inputBuffer;

    __VOLK_ATTR_ALIGNED(16) float squareBuffer[4];

    __m128 squareAccumulator = _mm_setzero_ps();
    __m128 aVal = _mm_setzero_ps();
    for(;number < quarterPoints; number++) {
      aVal = _mm_load_ps(aPtr);                     // aVal = x
      aVal = _mm_mul_ps(aVal, aVal);                // squareAccumulator += x^2
      squareAccumulator = _mm_add_ps(squareAccumulator, aVal);
      aPtr += 4;
    }
    _mm_store_ps(squareBuffer,squareAccumulator); // Store the results back into the C container
    returnValue = squareBuffer[0];
    returnValue += squareBuffer[1];
    returnValue += squareBuffer[2];
    returnValue += squareBuffer[3];

    number = quarterPoints * 4;
    for(;number < num_points; number++){
      returnValue += (*aPtr) * (*aPtr);
      aPtr++;
    }
    returnValue /= num_points;
    returnValue -= (mean * mean);
    returnValue = sqrtf(returnValue);
  }
  *stddev = returnValue;
}
#endif /* LV_HAVE_SSE */

#ifdef LV_HAVE_GENERIC
/*!
  \brief Calculates the standard deviation of the input buffer using the supplied mean
  \param stddev The calculated standard deviation
  \param inputBuffer The buffer of points to calculate the std deviation for
  \param mean The mean of the input buffer
  \param num_points The number of values in input buffer to used in the stddev calculation
*/
static inline void volk_32f_s32f_stddev_32f_generic(float* stddev, const float* inputBuffer, const float mean, unsigned int num_points){
  float returnValue = 0;
  if(num_points > 0){
    const float* aPtr = inputBuffer;
    unsigned int number = 0;

    for(number = 0; number < num_points; number++){
      returnValue += (*aPtr) * (*aPtr);
      aPtr++;
    }

    returnValue /= num_points;
    returnValue -= (mean * mean);
    returnValue = sqrtf(returnValue);
  }
  *stddev = returnValue;
}
#endif /* LV_HAVE_GENERIC */




#endif /* INCLUDED_volk_32f_s32f_stddev_32f_a_H */