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/* ----------------------------------------------------------------------  

* Copyright (C) 2010-2014 ARM Limited. All rights reserved.  

*  

* $Date:        19. March 2015

* $Revision:    V.1.4.5  

*  

* Project:          CMSIS DSP Library  

* Title:            arm_cfft_radix2_f32.c  

*  

* Description:  Radix-2 Decimation in Frequency CFFT & CIFFT Floating point processing function  

*  

*  

* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0

*  

* 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.

*   - Neither the name of ARM LIMITED nor the names of its contributors

*     may be used to endorse or promote products derived from this

*     software without specific prior written permission.

*

* 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.  

* -------------------------------------------------------------------- */

#include "arm_math.h"

void arm_radix2_butterfly_f32(

  float32_t * pSrc,

  uint32_t fftLen,

  float32_t * pCoef,

  uint16_t twidCoefModifier);

void arm_radix2_butterfly_inverse_f32(

  float32_t * pSrc,

  uint32_t fftLen,

  float32_t * pCoef,

  uint16_t twidCoefModifier,

  float32_t onebyfftLen);

extern void arm_bitreversal_f32(

    float32_t * pSrc,

    uint16_t fftSize,

    uint16_t bitRevFactor,

    uint16_t * pBitRevTab);

/**  

* @ingroup groupTransforms  

*/

/**  

* @addtogroup ComplexFFT  

* @{  

*/

/**  

* @details

* @brief Radix-2 CFFT/CIFFT.

* @deprecated Do not use this function.  It has been superseded by \ref arm_cfft_f32 and will be removed

* in the future.

* @param[in]      *S    points to an instance of the floating-point Radix-2 CFFT/CIFFT structure.  

* @param[in, out] *pSrc points to the complex data buffer of size <code>2*fftLen</code>. Processing occurs in-place.  

* @return none.

*/

void arm_cfft_radix2_f32(

const arm_cfft_radix2_instance_f32 * S,

float32_t * pSrc)

{

   if(S->ifftFlag == 1u)

   {

      /*  Complex IFFT radix-2  */

      arm_radix2_butterfly_inverse_f32(pSrc, S->fftLen, S->pTwiddle,

      S->twidCoefModifier, S->onebyfftLen);

   }

   else

   {

      /*  Complex FFT radix-2  */

      arm_radix2_butterfly_f32(pSrc, S->fftLen, S->pTwiddle,

      S->twidCoefModifier);

   }

   if(S->bitReverseFlag == 1u)

   {

      /*  Bit Reversal */

      arm_bitreversal_f32(pSrc, S->fftLen, S->bitRevFactor, S->pBitRevTable);

   }

}

/**    

* @} end of ComplexFFT group    

*/

/* ----------------------------------------------------------------------    

** Internal helper function used by the FFTs    

** ------------------------------------------------------------------- */

/*    

* @brief  Core function for the floating-point CFFT butterfly process.  

* @param[in, out] *pSrc            points to the in-place buffer of floating-point data type.  

* @param[in]      fftLen           length of the FFT.  

* @param[in]      *pCoef           points to the twiddle coefficient buffer.  

* @param[in]      twidCoefModifier twiddle coefficient modifier that supports different size FFTs with the same twiddle factor table.  

* @return none.  

*/

void arm_radix2_butterfly_f32(

float32_t * pSrc,

uint32_t fftLen,

float32_t * pCoef,

uint16_t twidCoefModifier)

{

   uint32_t i, j, k, l;

   uint32_t n1, n2, ia;

   float32_t xt, yt, cosVal, sinVal;

   float32_t p0, p1, p2, p3;

   float32_t a0, a1;

#ifndef ARM_MATH_CM0_FAMILY

   /*  Initializations for the first stage */

   n2 = fftLen >> 1;

   ia = 0;

   i = 0;

   // loop for groups 

   for (k = n2; k > 0; k--)

   {

      cosVal = pCoef[ia * 2];

      sinVal = pCoef[(ia * 2) + 1];

      /*  Twiddle coefficients index modifier */

      ia += twidCoefModifier;

      /*  index calculation for the input as, */

      /*  pSrc[i + 0], pSrc[i + fftLen/1] */

      l = i + n2;

      /*  Butterfly implementation */

      a0 = pSrc[2 * i] + pSrc[2 * l];

      xt = pSrc[2 * i] - pSrc[2 * l];

      yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];

      a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];

      p0 = xt * cosVal;

      p1 = yt * sinVal;

      p2 = yt * cosVal;

      p3 = xt * sinVal;  

      pSrc[2 * i]     = a0;  

      pSrc[2 * i + 1] = a1;      

      pSrc[2 * l]     = p0 + p1;

      pSrc[2 * l + 1] = p2 - p3;

      i++;

   }                             // groups loop end 

   twidCoefModifier <<= 1u;

   // loop for stage 

   for (k = n2; k > 2; k = k >> 1)

   {

      n1 = n2;

      n2 = n2 >> 1;

      ia = 0;

      // loop for groups 

      j = 0;

      do

      {

         cosVal = pCoef[ia * 2];

         sinVal = pCoef[(ia * 2) + 1];

         ia += twidCoefModifier;

         // loop for butterfly 

         i = j;

         do

         {

            l = i + n2;

            a0 = pSrc[2 * i] + pSrc[2 * l];

            xt = pSrc[2 * i] - pSrc[2 * l];

            yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];

            a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];

            p0 = xt * cosVal;

            p1 = yt * sinVal;

            p2 = yt * cosVal;

            p3 = xt * sinVal;  

            pSrc[2 * i] = a0;  

            pSrc[2 * i + 1] = a1;      

            pSrc[2 * l]     = p0 + p1;

            pSrc[2 * l + 1] = p2 - p3;

            i += n1;

         } while( i < fftLen );                        // butterfly loop end 

         j++;

      } while( j < n2);                          // groups loop end 

      twidCoefModifier <<= 1u;

   }                             // stages loop end 

   // loop for butterfly 

   for (i = 0; i < fftLen; i += 2)

   {

      a0 = pSrc[2 * i] + pSrc[2 * i + 2];

      xt = pSrc[2 * i] - pSrc[2 * i + 2];

      yt = pSrc[2 * i + 1] - pSrc[2 * i + 3];

      a1 = pSrc[2 * i + 3] + pSrc[2 * i + 1];

      pSrc[2 * i] = a0;  

      pSrc[2 * i + 1] = a1;

      pSrc[2 * i + 2] = xt;

      pSrc[2 * i + 3] = yt;

   }                             // groups loop end 

#else

   n2 = fftLen;

   // loop for stage 

   for (k = fftLen; k > 1; k = k >> 1)

   {

      n1 = n2;

      n2 = n2 >> 1;

      ia = 0;

      // loop for groups 

      j = 0;

      do

      {

         cosVal = pCoef[ia * 2];

         sinVal = pCoef[(ia * 2) + 1];

         ia += twidCoefModifier;

         // loop for butterfly 

         i = j;

         do

         {

            l = i + n2;

            a0 = pSrc[2 * i] + pSrc[2 * l];

            xt = pSrc[2 * i] - pSrc[2 * l];

            yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];

            a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];

            p0 = xt * cosVal;

            p1 = yt * sinVal;

            p2 = yt * cosVal;

            p3 = xt * sinVal;  

            pSrc[2 * i] = a0;  

            pSrc[2 * i + 1] = a1;      

            pSrc[2 * l]     = p0 + p1;

            pSrc[2 * l + 1] = p2 - p3;

            i += n1;

         } while(i < fftLen);

         j++;

      } while(j < n2);

      twidCoefModifier <<= 1u;

   }

#endif //    #ifndef ARM_MATH_CM0_FAMILY

}

void arm_radix2_butterfly_inverse_f32(

float32_t * pSrc,

uint32_t fftLen,

float32_t * pCoef,

uint16_t twidCoefModifier,

float32_t onebyfftLen)

{

   uint32_t i, j, k, l;

   uint32_t n1, n2, ia;

   float32_t xt, yt, cosVal, sinVal;

   float32_t p0, p1, p2, p3;

   float32_t a0, a1;

#ifndef ARM_MATH_CM0_FAMILY

   n2 = fftLen >> 1;

   ia = 0;

   // loop for groups 

   for (i = 0; i < n2; i++)

   {

      cosVal = pCoef[ia * 2];

      sinVal = pCoef[(ia * 2) + 1];

      ia += twidCoefModifier;

      l = i + n2;

      a0 = pSrc[2 * i] + pSrc[2 * l];

      xt = pSrc[2 * i] - pSrc[2 * l];

      yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];

      a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];

      p0 = xt * cosVal;

      p1 = yt * sinVal;

      p2 = yt * cosVal;

      p3 = xt * sinVal;  

      pSrc[2 * i] = a0;  

      pSrc[2 * i + 1] = a1;      

      pSrc[2 * l]     = p0 - p1;

      pSrc[2 * l + 1] = p2 + p3;  

   }                             // groups loop end 

   twidCoefModifier <<= 1u;

   // loop for stage 

   for (k = fftLen / 2; k > 2; k = k >> 1)

   {

      n1 = n2;

      n2 = n2 >> 1;

      ia = 0;

      // loop for groups 

      j = 0;

      do

      {

         cosVal = pCoef[ia * 2];

         sinVal = pCoef[(ia * 2) + 1];

         ia += twidCoefModifier;

         // loop for butterfly 

         i = j;

         do

         {

            l = i + n2;

            a0 = pSrc[2 * i] + pSrc[2 * l];

            xt = pSrc[2 * i] - pSrc[2 * l];

            yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];

            a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];

            p0 = xt * cosVal;

            p1 = yt * sinVal;

            p2 = yt * cosVal;

            p3 = xt * sinVal;  

            pSrc[2 * i] = a0;  

            pSrc[2 * i + 1] = a1;      

            pSrc[2 * l]     = p0 - p1;

            pSrc[2 * l + 1] = p2 + p3;

            i += n1;

         } while( i < fftLen );                 // butterfly loop end 

         j++;

      } while(j < n2);                      // groups loop end 

      twidCoefModifier <<= 1u;

   }                             // stages loop end 

   // loop for butterfly 

   for (i = 0; i < fftLen; i += 2)

   {  

      a0 = pSrc[2 * i] + pSrc[2 * i + 2];

      xt = pSrc[2 * i] - pSrc[2 * i + 2];

      a1 = pSrc[2 * i + 3] + pSrc[2 * i + 1];

      yt = pSrc[2 * i + 1] - pSrc[2 * i + 3];

      p0 = a0 * onebyfftLen;

      p2 = xt * onebyfftLen;

      p1 = a1 * onebyfftLen;

      p3 = yt * onebyfftLen;

      pSrc[2 * i] = p0;

      pSrc[2 * i + 1] = p1;  

      pSrc[2 * i + 2] = p2;      

      pSrc[2 * i + 3] = p3;

   }                             // butterfly loop end 

#else

   n2 = fftLen;

   // loop for stage 

   for (k = fftLen; k > 2; k = k >> 1)

   {

      n1 = n2;

      n2 = n2 >> 1;

      ia = 0;

      // loop for groups 

      j = 0;

      do

      {

         cosVal = pCoef[ia * 2];

         sinVal = pCoef[(ia * 2) + 1];

         ia = ia + twidCoefModifier;

         // loop for butterfly 

         i = j;

         do

         {

            l = i + n2;

            a0 = pSrc[2 * i] + pSrc[2 * l];

            xt = pSrc[2 * i] - pSrc[2 * l];

            yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];

            a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];

            p0 = xt * cosVal;

            p1 = yt * sinVal;

            p2 = yt * cosVal;

            p3 = xt * sinVal;  

            pSrc[2 * i] = a0;  

            pSrc[2 * i + 1] = a1;      

            pSrc[2 * l]     = p0 - p1;

            pSrc[2 * l + 1] = p2 + p3;  

            i += n1;

         } while( i < fftLen );                    // butterfly loop end 

         j++;

      } while( j < n2 );                      // groups loop end 

      twidCoefModifier = twidCoefModifier << 1u;

   }                             // stages loop end 

   n1 = n2;

   n2 = n2 >> 1;

   // loop for butterfly 

   for (i = 0; i < fftLen; i += n1)

   {

      l = i + n2;

      a0 = pSrc[2 * i] + pSrc[2 * l];

      xt = pSrc[2 * i] - pSrc[2 * l];

      a1 = pSrc[2 * l + 1] + pSrc[2 * i + 1];

      yt = pSrc[2 * i + 1] - pSrc[2 * l + 1];

      p0 = a0 * onebyfftLen;

      p2 = xt * onebyfftLen;

      p1 = a1 * onebyfftLen;

      p3 = yt * onebyfftLen;

      pSrc[2 * i] = p0;

      pSrc[2u * l] = p2;

      pSrc[2 * i + 1] = p1;    

      pSrc[2u * l + 1u] = p3;

   }                             // butterfly loop end 

#endif //      #ifndef ARM_MATH_CM0_FAMILY

}