tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/ComplexMathFunctions/arm_cmplx_conj_q31.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_q31.c
   9 *
  10 * Description:  Q31 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  * @addtogroup cmplx_conj
  48  * @{
  49  */
  50
  51 /**
  52  * @brief  Q31 complex conjugate.
  53  * @param  *pSrc points to the input vector
  54  * @param  *pDst points to the output vector
  55  * @param  numSamples number of complex samples in each vector
  56  * @return none.
  57  *
  58  * <b>Scaling and Overflow Behavior:</b>
  59  * \par
  60  * The function uses saturating arithmetic.
  61  * The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.
  62  */
  63
  64 void arm_cmplx_conj_q31(
  65   q31_t * pSrc,
  66   q31_t * pDst,
  67   uint32_t numSamples)
  68 {
  69   uint32_t blkCnt;                               /* loop counter */
  70   q31_t in;                                      /* Input value */
  71
  72 #ifndef ARM_MATH_CM0_FAMILY
  73
  74   /* Run the below code for Cortex-M4 and Cortex-M3 */
  75   q31_t inR1, inR2, inR3, inR4;                  /* Temporary real variables */
  76   q31_t inI1, inI2, inI3, inI4;                  /* Temporary imaginary variables */
  77
  78   /*loop Unrolling */
  79   blkCnt = numSamples >> 2u;
  80
  81   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  82    ** a second loop below computes the remaining 1 to 3 samples. */
  83   while(blkCnt > 0u)
  84   {
  85     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
  86     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
  87     /* Saturated to 0x7fffffff if the input is -1(0x80000000) */
  88     /* read real input sample */
  89     inR1 = pSrc[0];
  90     /* store real input sample */
  91     pDst[0] = inR1;
  92
  93     /* read imaginary input sample */
  94     inI1 = pSrc[1];
  95
  96     /* read real input sample */
  97     inR2 = pSrc[2];
  98     /* store real input sample */
  99     pDst[2] = inR2;
 100
 101     /* read imaginary input sample */
 102     inI2 = pSrc[3];
 103
 104     /* negate imaginary input sample */
 105     inI1 = __QSUB(0, inI1);
 106
 107     /* read real input sample */
 108     inR3 = pSrc[4];
 109     /* store real input sample */
 110     pDst[4] = inR3;
 111
 112     /* read imaginary input sample */
 113     inI3 = pSrc[5];
 114
 115     /* negate imaginary input sample */
 116     inI2 = __QSUB(0, inI2);
 117
 118     /* read real input sample */
 119     inR4 = pSrc[6];
 120     /* store real input sample */
 121     pDst[6] = inR4;
 122
 123     /* negate imaginary input sample */
 124     inI3 = __QSUB(0, inI3);
 125
 126     /* store imaginary input sample */
 127     inI4 = pSrc[7];
 128
 129     /* store imaginary input samples */
 130     pDst[1] = inI1;
 131
 132     /* negate imaginary input sample */
 133     inI4 = __QSUB(0, inI4);
 134
 135     /* store imaginary input samples */
 136     pDst[3] = inI2;
 137
 138     /* increment source pointer by 8 to proecess next samples */
 139     pSrc += 8u;
 140
 141     /* store imaginary input samples */
 142     pDst[5] = inI3;
 143     pDst[7] = inI4;
 144
 145     /* increment destination pointer by 8 to process next samples */
 146     pDst += 8u;
 147
 148     /* Decrement the loop counter */
 149     blkCnt--;
 150   }
 151
 152   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
 153    ** No loop unrolling is used. */
 154   blkCnt = numSamples % 0x4u;
 155
 156 #else
 157
 158   /* Run the below code for Cortex-M0 */
 159   blkCnt = numSamples;
 160
 161
 162 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 163
 164   while(blkCnt > 0u)
 165   {
 166     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
 167     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
 168     /* Saturated to 0x7fffffff if the input is -1(0x80000000) */
 169     *pDst++ = *pSrc++;
 170     in = *pSrc++;
 171     *pDst++ = (in == INT32_MIN) ? INT32_MAX : -in;
 172
 173     /* Decrement the loop counter */
 174     blkCnt--;
 175   }
 176 }
 177
 178 /**
 179  * @} end of cmplx_conj group
 180  */