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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_cmplx_mag_q31.c    

*    

* Description:  Q31 complex magnitude    

*    

* 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"

/**        

 * @ingroup groupCmplxMath        

 */

/**        

 * @addtogroup cmplx_mag        

 * @{        

 */

/**        

 * @brief  Q31 complex magnitude        

 * @param  *pSrc points to the complex input vector        

 * @param  *pDst points to the real output vector        

 * @param  numSamples number of complex samples in the input vector        

 * @return none.        

 *        

 * <b>Scaling and Overflow Behavior:</b>        

 * \par        

 * The function implements 1.31 by 1.31 multiplications and finally output is converted into 2.30 format.        

 * Input down scaling is not required.        

 */

void arm_cmplx_mag_q31(

  q31_t * pSrc,

  q31_t * pDst,

  uint32_t numSamples)

{

  q31_t real, imag;                              /* Temporary variables to hold input values */

  q31_t acc0, acc1;                              /* Accumulators */

  uint32_t blkCnt;                               /* loop counter */

#ifndef ARM_MATH_CM0_FAMILY

  /* Run the below code for Cortex-M4 and Cortex-M3 */

  q31_t real1, real2, imag1, imag2;              /* Temporary variables to hold input values */

  q31_t out1, out2, out3, out4;                  /* Accumulators */

  q63_t mul1, mul2, mul3, mul4;                  /* Temporary variables */

  /*loop Unrolling */

  blkCnt = numSamples >> 2u;

  /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.        

   ** a second loop below computes the remaining 1 to 3 samples. */

  while(blkCnt > 0u)

  {

    /* read complex input from source buffer */

    real1 = pSrc[0];

    imag1 = pSrc[1];

    real2 = pSrc[2];

    imag2 = pSrc[3];

    /* calculate power of input values */

    mul1 = (q63_t) real1 *real1;

    mul2 = (q63_t) imag1 *imag1;

    mul3 = (q63_t) real2 *real2;

    mul4 = (q63_t) imag2 *imag2;

    /* get the result to 3.29 format */

    out1 = (q31_t) (mul1 >> 33);

    out2 = (q31_t) (mul2 >> 33);

    out3 = (q31_t) (mul3 >> 33);

    out4 = (q31_t) (mul4 >> 33);

    /* add real and imaginary accumulators */

    out1 = out1 + out2;

    out3 = out3 + out4;

    /* read complex input from source buffer */

    real1 = pSrc[4];

    imag1 = pSrc[5];

    real2 = pSrc[6];

    imag2 = pSrc[7];

    /* calculate square root */

    arm_sqrt_q31(out1, &pDst[0]);

    /* calculate power of input values */

    mul1 = (q63_t) real1 *real1;

    /* calculate square root */

    arm_sqrt_q31(out3, &pDst[1]);

    /* calculate power of input values */

    mul2 = (q63_t) imag1 *imag1;

    mul3 = (q63_t) real2 *real2;

    mul4 = (q63_t) imag2 *imag2;

    /* get the result to 3.29 format */

    out1 = (q31_t) (mul1 >> 33);

    out2 = (q31_t) (mul2 >> 33);

    out3 = (q31_t) (mul3 >> 33);

    out4 = (q31_t) (mul4 >> 33);

    /* add real and imaginary accumulators */

    out1 = out1 + out2;

    out3 = out3 + out4;

    /* calculate square root */

    arm_sqrt_q31(out1, &pDst[2]);

    /* increment destination by 8 to process next samples */

    pSrc += 8u;

    /* calculate square root */

    arm_sqrt_q31(out3, &pDst[3]);

    /* increment destination by 4 to process next samples */

    pDst += 4u;

    /* Decrement the loop counter */

    blkCnt--;

  }

  /* If the numSamples is not a multiple of 4, compute any remaining output samples here.        

   ** No loop unrolling is used. */

  blkCnt = numSamples % 0x4u;

#else

  /* Run the below code for Cortex-M0 */

  blkCnt = numSamples;

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

  while(blkCnt > 0u)

  {

    /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */

    real = *pSrc++;

    imag = *pSrc++;

    acc0 = (q31_t) (((q63_t) real * real) >> 33);

    acc1 = (q31_t) (((q63_t) imag * imag) >> 33);

    /* store the result in 2.30 format in the destination buffer. */

    arm_sqrt_q31(acc0 + acc1, pDst++);

    /* Decrement the loop counter */

    blkCnt--;

  }

}

/**        

 * @} end of cmplx_mag group        

 */