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  1. /* ----------------------------------------------------------------------
  2.  * Project:      CMSIS DSP Library
  3.  * Title:        arm_cmplx_mag_q15.c
  4.  * Description:  Q15 complex magnitude
  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
  37.  * @{
  38.  */
  39.  
  40.  
  41. /**
  42.  * @brief  Q15 complex magnitude
  43.  * @param  *pSrc points to the complex input vector
  44.  * @param  *pDst points to the real output vector
  45.  * @param  numSamples number of complex samples in the input vector
  46.  * @return none.
  47.  *
  48.  * <b>Scaling and Overflow Behavior:</b>
  49.  * \par
  50.  * The function implements 1.15 by 1.15 multiplications and finally output is converted into 2.14 format.
  51.  */
  52.  
  53. void arm_cmplx_mag_q15(
  54.   q15_t * pSrc,
  55.   q15_t * pDst,
  56.   uint32_t numSamples)
  57. {
  58.   q31_t acc0, acc1;                              /* Accumulators */
  59.  
  60. #if defined (ARM_MATH_DSP)
  61.  
  62.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  63.   uint32_t blkCnt;                               /* loop counter */
  64.   q31_t in1, in2, in3, in4;
  65.   q31_t acc2, acc3;
  66.  
  67.  
  68.   /*loop Unrolling */
  69.   blkCnt = numSamples >> 2U;
  70.  
  71.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  72.    ** a second loop below computes the remaining 1 to 3 samples. */
  73.   while (blkCnt > 0U)
  74.   {
  75.  
  76.     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
  77.     in1 = *__SIMD32(pSrc)++;
  78.     in2 = *__SIMD32(pSrc)++;
  79.     in3 = *__SIMD32(pSrc)++;
  80.     in4 = *__SIMD32(pSrc)++;
  81.  
  82.     acc0 = __SMUAD(in1, in1);
  83.     acc1 = __SMUAD(in2, in2);
  84.     acc2 = __SMUAD(in3, in3);
  85.     acc3 = __SMUAD(in4, in4);
  86.  
  87.     /* store the result in 2.14 format in the destination buffer. */
  88.     arm_sqrt_q15((q15_t) ((acc0) >> 17), pDst++);
  89.     arm_sqrt_q15((q15_t) ((acc1) >> 17), pDst++);
  90.     arm_sqrt_q15((q15_t) ((acc2) >> 17), pDst++);
  91.     arm_sqrt_q15((q15_t) ((acc3) >> 17), pDst++);
  92.  
  93.     /* Decrement the loop counter */
  94.     blkCnt--;
  95.   }
  96.  
  97.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
  98.    ** No loop unrolling is used. */
  99.   blkCnt = numSamples % 0x4U;
  100.  
  101.   while (blkCnt > 0U)
  102.   {
  103.     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
  104.     in1 = *__SIMD32(pSrc)++;
  105.     acc0 = __SMUAD(in1, in1);
  106.  
  107.     /* store the result in 2.14 format in the destination buffer. */
  108.     arm_sqrt_q15((q15_t) (acc0 >> 17), pDst++);
  109.  
  110.     /* Decrement the loop counter */
  111.     blkCnt--;
  112.   }
  113.  
  114. #else
  115.  
  116.   /* Run the below code for Cortex-M0 */
  117.   q15_t real, imag;                              /* Temporary variables to hold input values */
  118.  
  119.   while (numSamples > 0U)
  120.   {
  121.     /* out = sqrt(real * real + imag * imag) */
  122.     real = *pSrc++;
  123.     imag = *pSrc++;
  124.  
  125.     acc0 = (real * real);
  126.     acc1 = (imag * imag);
  127.  
  128.     /* store the result in 2.14 format in the destination buffer. */
  129.     arm_sqrt_q15((q15_t) (((q63_t) acc0 + acc1) >> 17), pDst++);
  130.  
  131.     /* Decrement the loop counter */
  132.     numSamples--;
  133.   }
  134.  
  135. #endif /* #if defined (ARM_MATH_DSP) */
  136.  
  137. }
  138.  
  139. /**
  140.  * @} end of cmplx_mag group
  141.  */
  142.