DSP/Source/ComplexMathFunctions/arm_cmplx_mag_q15.c

/* ----------------------------------------------------------------------
 * Project:      CMSIS DSP Library
 * Title:        arm_cmplx_mag_q15.c
 * Description:  Q15 complex magnitude
 *
 * $Date:        27. January 2017
 * $Revision:    V.1.5.1
 *
 * Target Processor: Cortex-M cores
 * -------------------------------------------------------------------- */
/*
 * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
 *
 * SPDX-License-Identifier: Apache-2.0
 *
 * Licensed under the Apache License, Version 2.0 (the License); you may
 * not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @addtogroup cmplx_mag
 * @{
 */


/**
 * @brief  Q15 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 1.15 by 1.15 multiplications and finally output is converted into 2.14 format.
 */

void arm_cmplx_mag_q15(
  q15_t * pSrc,
  q15_t * pDst,
  uint32_t numSamples)
{
  q31_t acc0, acc1;                              /* Accumulators */

#if defined (ARM_MATH_DSP)

  /* Run the below code for Cortex-M4 and Cortex-M3 */
  uint32_t blkCnt;                               /* loop counter */
  q31_t in1, in2, in3, in4;
  q31_t acc2, acc3;


  /*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)
  {

    /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
    in1 = *__SIMD32(pSrc)++;
    in2 = *__SIMD32(pSrc)++;
    in3 = *__SIMD32(pSrc)++;
    in4 = *__SIMD32(pSrc)++;

    acc0 = __SMUAD(in1, in1);
    acc1 = __SMUAD(in2, in2);
    acc2 = __SMUAD(in3, in3);
    acc3 = __SMUAD(in4, in4);

    /* store the result in 2.14 format in the destination buffer. */
    arm_sqrt_q15((q15_t) ((acc0) >> 17), pDst++);
    arm_sqrt_q15((q15_t) ((acc1) >> 17), pDst++);
    arm_sqrt_q15((q15_t) ((acc2) >> 17), pDst++);
    arm_sqrt_q15((q15_t) ((acc3) >> 17), pDst++);

    /* 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;

  while (blkCnt > 0U)
  {
    /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
    in1 = *__SIMD32(pSrc)++;
    acc0 = __SMUAD(in1, in1);

    /* store the result in 2.14 format in the destination buffer. */
    arm_sqrt_q15((q15_t) (acc0 >> 17), pDst++);

    /* Decrement the loop counter */
    blkCnt--;
  }

#else

  /* Run the below code for Cortex-M0 */
  q15_t real, imag;                              /* Temporary variables to hold input values */

  while (numSamples > 0U)
  {
    /* out = sqrt(real * real + imag * imag) */
    real = *pSrc++;
    imag = *pSrc++;

    acc0 = (real * real);
    acc1 = (imag * imag);

    /* store the result in 2.14 format in the destination buffer. */
    arm_sqrt_q15((q15_t) (((q63_t) acc0 + acc1) >> 17), pDst++);

    /* Decrement the loop counter */
    numSamples--;
  }

#endif /* #if defined (ARM_MATH_DSP) */

}

/**
 * @} end of cmplx_mag group
 */