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  1. /* ----------------------------------------------------------------------
  2.  * Project:      CMSIS DSP Library
  3.  * Title:        arm_cmplx_mag_squared_f32.c
  4.  * Description:  Floating-point 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.  * @defgroup cmplx_mag_squared Complex Magnitude Squared
  37.  *
  38.  * Computes the magnitude squared of the elements of a complex data vector.
  39.  *
  40.  * The <code>pSrc</code> points to the source data and
  41.  * <code>pDst</code> points to the where the result should be written.
  42.  * <code>numSamples</code> specifies the number of complex samples
  43.  * in the input array and the data is stored in an interleaved fashion
  44.  * (real, imag, real, imag, ...).
  45.  * The input array has a total of <code>2*numSamples</code> values;
  46.  * the output array has a total of <code>numSamples</code> values.
  47.  *
  48.  * The underlying algorithm is used:
  49.  *
  50.  * <pre>
  51.  * for(n=0; n<numSamples; n++) {
  52.  *     pDst[n] = pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2;
  53.  * }
  54.  * </pre>
  55.  *
  56.  * There are separate functions for floating-point, Q15, and Q31 data types.
  57.  */
  58.  
  59. /**
  60.  * @addtogroup cmplx_mag_squared
  61.  * @{
  62.  */
  63.  
  64.  
  65. /**
  66.  * @brief  Floating-point complex magnitude squared
  67.  * @param[in]  *pSrc points to the complex input vector
  68.  * @param[out]  *pDst points to the real output vector
  69.  * @param[in]  numSamples number of complex samples in the input vector
  70.  * @return none.
  71.  */
  72.  
  73. void arm_cmplx_mag_squared_f32(
  74.   float32_t * pSrc,
  75.   float32_t * pDst,
  76.   uint32_t numSamples)
  77. {
  78.   float32_t real, imag;                          /* Temporary variables to store real and imaginary values */
  79.   uint32_t blkCnt;                               /* loop counter */
  80.  
  81. #if defined (ARM_MATH_DSP)
  82.   float32_t real1, real2, real3, real4;          /* Temporary variables to hold real values */
  83.   float32_t imag1, imag2, imag3, imag4;          /* Temporary variables to hold imaginary values */
  84.   float32_t mul1, mul2, mul3, mul4;              /* Temporary variables */
  85.   float32_t mul5, mul6, mul7, mul8;              /* Temporary variables */
  86.   float32_t out1, out2, out3, out4;              /* Temporary variables to hold output values */
  87.  
  88.   /*loop Unrolling */
  89.   blkCnt = numSamples >> 2U;
  90.  
  91.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  92.    ** a second loop below computes the remaining 1 to 3 samples. */
  93.   while (blkCnt > 0U)
  94.   {
  95.     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
  96.     /* read real input sample from source buffer */
  97.     real1 = pSrc[0];
  98.     /* read imaginary input sample from source buffer */
  99.     imag1 = pSrc[1];
  100.  
  101.     /* calculate power of real value */
  102.     mul1 = real1 * real1;
  103.  
  104.     /* read real input sample from source buffer */
  105.     real2 = pSrc[2];
  106.  
  107.     /* calculate power of imaginary value */
  108.     mul2 = imag1 * imag1;
  109.  
  110.     /* read imaginary input sample from source buffer */
  111.     imag2 = pSrc[3];
  112.  
  113.     /* calculate power of real value */
  114.     mul3 = real2 * real2;
  115.  
  116.     /* read real input sample from source buffer */
  117.     real3 = pSrc[4];
  118.  
  119.     /* calculate power of imaginary value */
  120.     mul4 = imag2 * imag2;
  121.  
  122.     /* read imaginary input sample from source buffer */
  123.     imag3 = pSrc[5];
  124.  
  125.     /* calculate power of real value */
  126.     mul5 = real3 * real3;
  127.     /* calculate power of imaginary value */
  128.     mul6 = imag3 * imag3;
  129.  
  130.     /* read real input sample from source buffer */
  131.     real4 = pSrc[6];
  132.  
  133.     /* accumulate real and imaginary powers */
  134.     out1 = mul1 + mul2;
  135.  
  136.     /* read imaginary input sample from source buffer */
  137.     imag4 = pSrc[7];
  138.  
  139.     /* accumulate real and imaginary powers */
  140.     out2 = mul3 + mul4;
  141.  
  142.     /* calculate power of real value */
  143.     mul7 = real4 * real4;
  144.     /* calculate power of imaginary value */
  145.     mul8 = imag4 * imag4;
  146.  
  147.     /* store output to destination */
  148.     pDst[0] = out1;
  149.  
  150.     /* accumulate real and imaginary powers */
  151.     out3 = mul5 + mul6;
  152.  
  153.     /* store output to destination */
  154.     pDst[1] = out2;
  155.  
  156.     /* accumulate real and imaginary powers */
  157.     out4 = mul7 + mul8;
  158.  
  159.     /* store output to destination */
  160.     pDst[2] = out3;
  161.  
  162.     /* increment destination pointer by 8 to process next samples */
  163.     pSrc += 8U;
  164.  
  165.     /* store output to destination */
  166.     pDst[3] = out4;
  167.  
  168.     /* increment destination pointer by 4 to process next samples */
  169.     pDst += 4U;
  170.  
  171.     /* Decrement the loop counter */
  172.     blkCnt--;
  173.   }
  174.  
  175.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
  176.    ** No loop unrolling is used. */
  177.   blkCnt = numSamples % 0x4U;
  178.  
  179. #else
  180.  
  181.   /* Run the below code for Cortex-M0 */
  182.  
  183.   blkCnt = numSamples;
  184.  
  185. #endif /* #if defined (ARM_MATH_DSP) */
  186.  
  187.   while (blkCnt > 0U)
  188.   {
  189.     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
  190.     real = *pSrc++;
  191.     imag = *pSrc++;
  192.  
  193.     /* out = (real * real) + (imag * imag) */
  194.     /* store the result in the destination buffer. */
  195.     *pDst++ = (real * real) + (imag * imag);
  196.  
  197.     /* Decrement the loop counter */
  198.     blkCnt--;
  199.   }
  200. }
  201.  
  202. /**
  203.  * @} end of cmplx_mag_squared group
  204.  */
  205.