tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/ComplexMathFunctions/arm_cmplx_mag_f32.c

   1 /* ----------------------------------------------------------------------
   2 * Copyright (C) 2010-2013 ARM Limited. All rights reserved.
   3 *
   4 * $Date:        17. January 2013
   5 * $Revision:    V1.4.1
   6 *
   7 * Project:          CMSIS DSP Library
   8 * Title:                arm_cmplx_mag_f32.c
   9 *
  10 * Description:  Floating-point complex magnitude.
  11 *
  12 * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  13 *
  14 * Redistribution and use in source and binary forms, with or without
  15 * modification, are permitted provided that the following conditions
  16 * are met:
  17 *   - Redistributions of source code must retain the above copyright
  18 *     notice, this list of conditions and the following disclaimer.
  19 *   - Redistributions in binary form must reproduce the above copyright
  20 *     notice, this list of conditions and the following disclaimer in
  21 *     the documentation and/or other materials provided with the
  22 *     distribution.
  23 *   - Neither the name of ARM LIMITED nor the names of its contributors
  24 *     may be used to endorse or promote products derived from this
  25 *     software without specific prior written permission.
  26 *
  27 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  28 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  29 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  30 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  31 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  32 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  33 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  34 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  35 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  36 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  37 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  38 * POSSIBILITY OF SUCH DAMAGE.
  39 * ---------------------------------------------------------------------------- */
  40
  41 #include "arm_math.h"
  42
  43 /**
  44  * @ingroup groupCmplxMath
  45  */
  46
  47 /**
  48  * @defgroup cmplx_mag Complex Magnitude
  49  *
  50  * Computes the magnitude of the elements of a complex data vector.
  51  *
  52  * The <code>pSrc</code> points to the source data and
  53  * <code>pDst</code> points to the where the result should be written.
  54  * <code>numSamples</code> specifies the number of complex samples
  55  * in the input array and the data is stored in an interleaved fashion
  56  * (real, imag, real, imag, ...).
  57  * The input array has a total of <code>2*numSamples</code> values;
  58  * the output array has a total of <code>numSamples</code> values.
  59  * The underlying algorithm is used:
  60  *
  61  * <pre>
  62  * for(n=0; n<numSamples; n++) {
  63  *     pDst[n] = sqrt(pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2);
  64  * }
  65  * </pre>
  66  *
  67  * There are separate functions for floating-point, Q15, and Q31 data types.
  68  */
  69
  70 /**
  71  * @addtogroup cmplx_mag
  72  * @{
  73  */
  74 /**
  75  * @brief Floating-point complex magnitude.
  76  * @param[in]       *pSrc points to complex input buffer
  77  * @param[out]      *pDst points to real output buffer
  78  * @param[in]       numSamples number of complex samples in the input vector
  79  * @return none.
  80  *
  81  */
  82
  83
  84 void arm_cmplx_mag_f32(
  85   float32_t * pSrc,
  86   float32_t * pDst,
  87   uint32_t numSamples)
  88 {
  89   float32_t realIn, imagIn;                      /* Temporary variables to hold input values */
  90
  91 #ifndef ARM_MATH_CM0_FAMILY
  92
  93   /* Run the below code for Cortex-M4 and Cortex-M3 */
  94   uint32_t blkCnt;                               /* loop counter */
  95
  96   /*loop Unrolling */
  97   blkCnt = numSamples >> 2u;
  98
  99   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
 100    ** a second loop below computes the remaining 1 to 3 samples. */
 101   while(blkCnt > 0u)
 102   {
 103
 104     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
 105     realIn = *pSrc++;
 106     imagIn = *pSrc++;
 107     /* store the result in the destination buffer. */
 108     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
 109
 110     realIn = *pSrc++;
 111     imagIn = *pSrc++;
 112     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
 113
 114     realIn = *pSrc++;
 115     imagIn = *pSrc++;
 116     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
 117
 118     realIn = *pSrc++;
 119     imagIn = *pSrc++;
 120     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
 121
 122
 123     /* Decrement the loop counter */
 124     blkCnt--;
 125   }
 126
 127   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
 128    ** No loop unrolling is used. */
 129   blkCnt = numSamples % 0x4u;
 130
 131   while(blkCnt > 0u)
 132   {
 133     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
 134     realIn = *pSrc++;
 135     imagIn = *pSrc++;
 136     /* store the result in the destination buffer. */
 137     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
 138
 139     /* Decrement the loop counter */
 140     blkCnt--;
 141   }
 142
 143 #else
 144
 145   /* Run the below code for Cortex-M0 */
 146
 147   while(numSamples > 0u)
 148   {
 149     /* out = sqrt((real * real) + (imag * imag)) */
 150     realIn = *pSrc++;
 151     imagIn = *pSrc++;
 152     /* store the result in the destination buffer. */
 153     arm_sqrt_f32((realIn * realIn) + (imagIn * imagIn), pDst++);
 154
 155     /* Decrement the loop counter */
 156     numSamples--;
 157   }
 158
 159 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 160
 161 }
 162
 163 /**
 164  * @} end of cmplx_mag group
 165  */