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  1. /* ----------------------------------------------------------------------
  2.  * Project:      CMSIS DSP Library
  3.  * Title:        arm_cmplx_mag_squared_q15.c
  4.  * Description:  Q15 complex magnitude squared
  5.  *
  6.  * $Date:        27. January 2017
  7.  * $Revision:    V.1.5.1
  8.  *
  9.  * Target Processor: Cortex-M cores
  10.  * -------------------------------------------------------------------- */
  11. /*
  12.  * Copyright (C) 2010-2017 ARM Limited or its affiliates. All rights reserved.
  13.  *
  14.  * SPDX-License-Identifier: Apache-2.0
  15.  *
  16.  * Licensed under the Apache License, Version 2.0 (the License); you may
  17.  * not use this file except in compliance with the License.
  18.  * You may obtain a copy of the License at
  19.  *
  20.  * www.apache.org/licenses/LICENSE-2.0
  21.  *
  22.  * Unless required by applicable law or agreed to in writing, software
  23.  * distributed under the License is distributed on an AS IS BASIS, WITHOUT
  24.  * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  25.  * See the License for the specific language governing permissions and
  26.  * limitations under the License.
  27.  */
  28.  
  29. #include "arm_math.h"
  30.  
  31. /**
  32.  * @ingroup groupCmplxMath
  33.  */
  34.  
  35. /**
  36.  * @addtogroup cmplx_mag_squared
  37.  * @{
  38.  */
  39.  
  40. /**
  41.  * @brief  Q15 complex magnitude squared
  42.  * @param  *pSrc points to the complex input vector
  43.  * @param  *pDst points to the real output vector
  44.  * @param  numSamples number of complex samples in the input vector
  45.  * @return none.
  46.  *
  47.  * <b>Scaling and Overflow Behavior:</b>
  48.  * \par
  49.  * The function implements 1.15 by 1.15 multiplications and finally output is converted into 3.13 format.
  50.  */
  51.  
  52. void arm_cmplx_mag_squared_q15(
  53.   q15_t * pSrc,
  54.   q15_t * pDst,
  55.   uint32_t numSamples)
  56. {
  57.   q31_t acc0, acc1;                              /* Accumulators */
  58.  
  59. #if defined (ARM_MATH_DSP)
  60.  
  61.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  62.   uint32_t blkCnt;                               /* loop counter */
  63.   q31_t in1, in2, in3, in4;
  64.   q31_t acc2, acc3;
  65.  
  66.   /*loop Unrolling */
  67.   blkCnt = numSamples >> 2U;
  68.  
  69.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  70.    ** a second loop below computes the remaining 1 to 3 samples. */
  71.   while (blkCnt > 0U)
  72.   {
  73.     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
  74.     in1 = *__SIMD32(pSrc)++;
  75.     in2 = *__SIMD32(pSrc)++;
  76.     in3 = *__SIMD32(pSrc)++;
  77.     in4 = *__SIMD32(pSrc)++;
  78.  
  79.     acc0 = __SMUAD(in1, in1);
  80.     acc1 = __SMUAD(in2, in2);
  81.     acc2 = __SMUAD(in3, in3);
  82.     acc3 = __SMUAD(in4, in4);
  83.  
  84.     /* store the result in 3.13 format in the destination buffer. */
  85.     *pDst++ = (q15_t) (acc0 >> 17);
  86.     *pDst++ = (q15_t) (acc1 >> 17);
  87.     *pDst++ = (q15_t) (acc2 >> 17);
  88.     *pDst++ = (q15_t) (acc3 >> 17);
  89.  
  90.     /* Decrement the loop counter */
  91.     blkCnt--;
  92.   }
  93.  
  94.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
  95.    ** No loop unrolling is used. */
  96.   blkCnt = numSamples % 0x4U;
  97.  
  98.   while (blkCnt > 0U)
  99.   {
  100.     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
  101.     in1 = *__SIMD32(pSrc)++;
  102.     acc0 = __SMUAD(in1, in1);
  103.  
  104.     /* store the result in 3.13 format in the destination buffer. */
  105.     *pDst++ = (q15_t) (acc0 >> 17);
  106.  
  107.     /* Decrement the loop counter */
  108.     blkCnt--;
  109.   }
  110.  
  111. #else
  112.  
  113.   /* Run the below code for Cortex-M0 */
  114.   q15_t real, imag;                              /* Temporary variables to store real and imaginary values */
  115.  
  116.   while (numSamples > 0U)
  117.   {
  118.     /* out = ((real * real) + (imag * imag)) */
  119.     real = *pSrc++;
  120.     imag = *pSrc++;
  121.     acc0 = (real * real);
  122.     acc1 = (imag * imag);
  123.     /* store the result in 3.13 format in the destination buffer. */
  124.     *pDst++ = (q15_t) (((q63_t) acc0 + acc1) >> 17);
  125.  
  126.     /* Decrement the loop counter */
  127.     numSamples--;
  128.   }
  129.  
  130. #endif /* #if defined (ARM_MATH_DSP) */
  131.  
  132. }
  133.  
  134. /**
  135.  * @} end of cmplx_mag_squared group
  136.  */
  137.