tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/ComplexMathFunctions/arm_cmplx_conj_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_conj_f32.c
   9 *
  10 * Description:  Floating-point complex conjugate.
  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 #include "arm_math.h"
  41
  42 /**
  43  * @ingroup groupCmplxMath
  44  */
  45
  46 /**
  47  * @defgroup cmplx_conj Complex Conjugate
  48  *
  49  * Conjugates the elements of a complex data vector.
  50  *
  51  * The <code>pSrc</code> points to the source data and
  52  * <code>pDst</code> points to the where the result should be written.
  53  * <code>numSamples</code> specifies the number of complex samples
  54  * and the data in each array is stored in an interleaved fashion
  55  * (real, imag, real, imag, ...).
  56  * Each array has a total of <code>2*numSamples</code> values.
  57  * The underlying algorithm is used:
  58  *
  59  * <pre>
  60  * for(n=0; n<numSamples; n++) {
  61  *     pDst[(2*n)+0)] = pSrc[(2*n)+0];     // real part
  62  *     pDst[(2*n)+1)] = -pSrc[(2*n)+1];    // imag part
  63  * }
  64  * </pre>
  65  *
  66  * There are separate functions for floating-point, Q15, and Q31 data types.
  67  */
  68
  69 /**
  70  * @addtogroup cmplx_conj
  71  * @{
  72  */
  73
  74 /**
  75  * @brief  Floating-point complex conjugate.
  76  * @param  *pSrc points to the input vector
  77  * @param  *pDst points to the output vector
  78  * @param  numSamples number of complex samples in each vector
  79  * @return none.
  80  */
  81
  82 void arm_cmplx_conj_f32(
  83   float32_t * pSrc,
  84   float32_t * pDst,
  85   uint32_t numSamples)
  86 {
  87   uint32_t blkCnt;                               /* loop counter */
  88
  89 #ifndef ARM_MATH_CM0_FAMILY
  90
  91   /* Run the below code for Cortex-M4 and Cortex-M3 */
  92   float32_t inR1, inR2, inR3, inR4;
  93   float32_t inI1, inI2, inI3, inI4;
  94
  95   /*loop Unrolling */
  96   blkCnt = numSamples >> 2u;
  97
  98   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  99    ** a second loop below computes the remaining 1 to 3 samples. */
 100   while(blkCnt > 0u)
 101   {
 102     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
 103     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
 104     /* read real input samples */
 105     inR1 = pSrc[0];
 106     /* store real samples to destination */
 107     pDst[0] = inR1;
 108     inR2 = pSrc[2];
 109     pDst[2] = inR2;
 110     inR3 = pSrc[4];
 111     pDst[4] = inR3;
 112     inR4 = pSrc[6];
 113     pDst[6] = inR4;
 114
 115     /* read imaginary input samples */
 116     inI1 = pSrc[1];
 117     inI2 = pSrc[3];
 118
 119     /* conjugate input */
 120     inI1 = -inI1;
 121
 122     /* read imaginary input samples */
 123     inI3 = pSrc[5];
 124
 125     /* conjugate input */
 126     inI2 = -inI2;
 127
 128     /* read imaginary input samples */
 129     inI4 = pSrc[7];
 130
 131     /* conjugate input */
 132     inI3 = -inI3;
 133
 134     /* store imaginary samples to destination */
 135     pDst[1] = inI1;
 136     pDst[3] = inI2;
 137
 138     /* conjugate input */
 139     inI4 = -inI4;
 140
 141     /* store imaginary samples to destination */
 142     pDst[5] = inI3;
 143
 144     /* increment source pointer by 8 to process next sampels */
 145     pSrc += 8u;
 146
 147     /* store imaginary sample to destination */
 148     pDst[7] = inI4;
 149
 150     /* increment destination pointer by 8 to store next samples */
 151     pDst += 8u;
 152
 153     /* Decrement the loop counter */
 154     blkCnt--;
 155   }
 156
 157   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
 158    ** No loop unrolling is used. */
 159   blkCnt = numSamples % 0x4u;
 160
 161 #else
 162
 163   /* Run the below code for Cortex-M0 */
 164   blkCnt = numSamples;
 165
 166 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 167
 168   while(blkCnt > 0u)
 169   {
 170     /* realOut + j (imagOut) = realIn + j (-1) imagIn */
 171     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
 172     *pDst++ = *pSrc++;
 173     *pDst++ = -*pSrc++;
 174
 175     /* Decrement the loop counter */
 176     blkCnt--;
 177   }
 178 }
 179
 180 /**
 181  * @} end of cmplx_conj group
 182  */