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  1. /* ----------------------------------------------------------------------
  2.  * Project:      CMSIS DSP Library
  3.  * Title:        arm_cmplx_mag_q31.c
  4.  * Description:  Q31 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.  * @brief  Q31 complex magnitude
  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 1.31 by 1.31 multiplications and finally output is converted into 2.30 format.
  50.  * Input down scaling is not required.
  51.  */
  52.  
  53. void arm_cmplx_mag_q31(
  54.   q31_t * pSrc,
  55.   q31_t * pDst,
  56.   uint32_t numSamples)
  57. {
  58.   q31_t real, imag;                              /* Temporary variables to hold input values */
  59.   q31_t acc0, acc1;                              /* Accumulators */
  60.   uint32_t blkCnt;                               /* loop counter */
  61.  
  62. #if defined (ARM_MATH_DSP)
  63.  
  64.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  65.   q31_t real1, real2, imag1, imag2;              /* Temporary variables to hold input values */
  66.   q31_t out1, out2, out3, out4;                  /* Accumulators */
  67.   q63_t mul1, mul2, mul3, mul4;                  /* Temporary variables */
  68.  
  69.  
  70.   /*loop Unrolling */
  71.   blkCnt = numSamples >> 2U;
  72.  
  73.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  74.    ** a second loop below computes the remaining 1 to 3 samples. */
  75.   while (blkCnt > 0U)
  76.   {
  77.     /* read complex input from source buffer */
  78.     real1 = pSrc[0];
  79.     imag1 = pSrc[1];
  80.     real2 = pSrc[2];
  81.     imag2 = pSrc[3];
  82.  
  83.     /* calculate power of input values */
  84.     mul1 = (q63_t) real1 *real1;
  85.     mul2 = (q63_t) imag1 *imag1;
  86.     mul3 = (q63_t) real2 *real2;
  87.     mul4 = (q63_t) imag2 *imag2;
  88.  
  89.     /* get the result to 3.29 format */
  90.     out1 = (q31_t) (mul1 >> 33);
  91.     out2 = (q31_t) (mul2 >> 33);
  92.     out3 = (q31_t) (mul3 >> 33);
  93.     out4 = (q31_t) (mul4 >> 33);
  94.  
  95.     /* add real and imaginary accumulators */
  96.     out1 = out1 + out2;
  97.     out3 = out3 + out4;
  98.  
  99.     /* read complex input from source buffer */
  100.     real1 = pSrc[4];
  101.     imag1 = pSrc[5];
  102.     real2 = pSrc[6];
  103.     imag2 = pSrc[7];
  104.  
  105.     /* calculate square root */
  106.     arm_sqrt_q31(out1, &pDst[0]);
  107.  
  108.     /* calculate power of input values */
  109.     mul1 = (q63_t) real1 *real1;
  110.  
  111.     /* calculate square root */
  112.     arm_sqrt_q31(out3, &pDst[1]);
  113.  
  114.     /* calculate power of input values */
  115.     mul2 = (q63_t) imag1 *imag1;
  116.     mul3 = (q63_t) real2 *real2;
  117.     mul4 = (q63_t) imag2 *imag2;
  118.  
  119.     /* get the result to 3.29 format */
  120.     out1 = (q31_t) (mul1 >> 33);
  121.     out2 = (q31_t) (mul2 >> 33);
  122.     out3 = (q31_t) (mul3 >> 33);
  123.     out4 = (q31_t) (mul4 >> 33);
  124.  
  125.     /* add real and imaginary accumulators */
  126.     out1 = out1 + out2;
  127.     out3 = out3 + out4;
  128.  
  129.     /* calculate square root */
  130.     arm_sqrt_q31(out1, &pDst[2]);
  131.  
  132.     /* increment destination by 8 to process next samples */
  133.     pSrc += 8U;
  134.  
  135.     /* calculate square root */
  136.     arm_sqrt_q31(out3, &pDst[3]);
  137.  
  138.     /* increment destination by 4 to process next samples */
  139.     pDst += 4U;
  140.  
  141.     /* Decrement the loop counter */
  142.     blkCnt--;
  143.   }
  144.  
  145.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
  146.    ** No loop unrolling is used. */
  147.   blkCnt = numSamples % 0x4U;
  148.  
  149. #else
  150.  
  151.   /* Run the below code for Cortex-M0 */
  152.   blkCnt = numSamples;
  153.  
  154. #endif /* #if defined (ARM_MATH_DSP) */
  155.  
  156.   while (blkCnt > 0U)
  157.   {
  158.     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
  159.     real = *pSrc++;
  160.     imag = *pSrc++;
  161.     acc0 = (q31_t) (((q63_t) real * real) >> 33);
  162.     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
  163.     /* store the result in 2.30 format in the destination buffer. */
  164.     arm_sqrt_q31(acc0 + acc1, pDst++);
  165.  
  166.     /* Decrement the loop counter */
  167.     blkCnt--;
  168.   }
  169. }
  170.  
  171. /**
  172.  * @} end of cmplx_mag group
  173.  */
  174.