Subversion Repositories dashGPS

Rev

Rev 2 | Blame | Compare with Previous | Last modification | View Log | Download | RSS feed

  1. /* ----------------------------------------------------------------------
  2.  * Project:      CMSIS DSP Library
  3.  * Title:        arm_cmplx_mag_f32.c
  4.  * Description:  Floating-point 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.  * @defgroup cmplx_mag Complex Magnitude
  37.  *
  38.  * Computes the magnitude 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.  * The underlying algorithm is used:
  48.  *
  49.  * <pre>
  50.  * for(n=0; n<numSamples; n++) {
  51.  *     pDst[n] = sqrt(pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2);
  52.  * }
  53.  * </pre>
  54.  *
  55.  * There are separate functions for floating-point, Q15, and Q31 data types.
  56.  */
  57.  
  58. /**
  59.  * @addtogroup cmplx_mag
  60.  * @{
  61.  */
  62. /**
  63.  * @brief Floating-point complex magnitude.
  64.  * @param[in]       *pSrc points to complex input buffer
  65.  * @param[out]      *pDst points to real output buffer
  66.  * @param[in]       numSamples number of complex samples in the input vector
  67.  * @return none.
  68.  *
  69.  */
  70.  
  71.  
  72. void arm_cmplx_mag_f32(
  73.   float32_t * pSrc,
  74.   float32_t * pDst,
  75.   uint32_t numSamples)
  76. {
  77.   float32_t realIn, imagIn;                      /* Temporary variables to hold input values */
  78.  
  79. #if defined (ARM_MATH_DSP)
  80.  
  81.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  82.   uint32_t blkCnt;                               /* loop counter */
  83.  
  84.   /*loop Unrolling */
  85.   blkCnt = numSamples >> 2U;
  86.  
  87.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  88.    ** a second loop below computes the remaining 1 to 3 samples. */
  89.   while (blkCnt > 0U)
  90.   {
  91.  
  92.     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
  93.     realIn = *pSrc++;
  94.     imagIn = *pSrc++;
  95.     /* store the result in the destination buffer. */
  96.     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
  97.  
  98.     realIn = *pSrc++;
  99.     imagIn = *pSrc++;
  100.     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
  101.  
  102.     realIn = *pSrc++;
  103.     imagIn = *pSrc++;
  104.     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
  105.  
  106.     realIn = *pSrc++;
  107.     imagIn = *pSrc++;
  108.     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
  109.  
  110.  
  111.     /* Decrement the loop counter */
  112.     blkCnt--;
  113.   }
  114.  
  115.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
  116.    ** No loop unrolling is used. */
  117.   blkCnt = numSamples % 0x4U;
  118.  
  119.   while (blkCnt > 0U)
  120.   {
  121.     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
  122.     realIn = *pSrc++;
  123.     imagIn = *pSrc++;
  124.     /* store the result in the destination buffer. */
  125.     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
  126.  
  127.     /* Decrement the loop counter */
  128.     blkCnt--;
  129.   }
  130.  
  131. #else
  132.  
  133.   /* Run the below code for Cortex-M0 */
  134.  
  135.   while (numSamples > 0U)
  136.   {
  137.     /* out = sqrt((real * real) + (imag * imag)) */
  138.     realIn = *pSrc++;
  139.     imagIn = *pSrc++;
  140.     /* store the result in the destination buffer. */
  141.     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
  142.  
  143.     /* Decrement the loop counter */
  144.     numSamples--;
  145.   }
  146.  
  147. #endif /* #if defined (ARM_MATH_DSP) */
  148.  
  149. }
  150.  
  151. /**
  152.  * @} end of cmplx_mag group
  153.  */
  154.