tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/ComplexMathFunctions/arm_cmplx_mag_squared_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_mag_squared_q31.c
   9 *
  10 * Description:  Q31 complex magnitude squared.
  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  * @addtogroup cmplx_mag_squared
  49  * @{
  50  */
  51
  52
  53 /**
  54  * @brief  Q31 complex magnitude squared
  55  * @param  *pSrc points to the complex input vector
  56  * @param  *pDst points to the real output vector
  57  * @param  numSamples number of complex samples in the input vector
  58  * @return none.
  59  *
  60  * <b>Scaling and Overflow Behavior:</b>
  61  * \par
  62  * The function implements 1.31 by 1.31 multiplications and finally output is converted into 3.29 format.
  63  * Input down scaling is not required.
  64  */
  65
  66 void arm_cmplx_mag_squared_q31(
  67   q31_t * pSrc,
  68   q31_t * pDst,
  69   uint32_t numSamples)
  70 {
  71   q31_t real, imag;                              /* Temporary variables to store real and imaginary values */
  72   q31_t acc0, acc1;                              /* Accumulators */
  73
  74 #ifndef ARM_MATH_CM0_FAMILY
  75
  76   /* Run the below code for Cortex-M4 and Cortex-M3 */
  77   uint32_t blkCnt;                               /* loop counter */
  78
  79   /* loop Unrolling */
  80   blkCnt = numSamples >> 2u;
  81
  82   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  83    ** a second loop below computes the remaining 1 to 3 samples. */
  84   while(blkCnt > 0u)
  85   {
  86     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
  87     real = *pSrc++;
  88     imag = *pSrc++;
  89     acc0 = (q31_t) (((q63_t) real * real) >> 33);
  90     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
  91     /* store the result in 3.29 format in the destination buffer. */
  92     *pDst++ = acc0 + acc1;
  93
  94     real = *pSrc++;
  95     imag = *pSrc++;
  96     acc0 = (q31_t) (((q63_t) real * real) >> 33);
  97     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
  98     /* store the result in 3.29 format in the destination buffer. */
  99     *pDst++ = acc0 + acc1;
 100
 101     real = *pSrc++;
 102     imag = *pSrc++;
 103     acc0 = (q31_t) (((q63_t) real * real) >> 33);
 104     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
 105     /* store the result in 3.29 format in the destination buffer. */
 106     *pDst++ = acc0 + acc1;
 107
 108     real = *pSrc++;
 109     imag = *pSrc++;
 110     acc0 = (q31_t) (((q63_t) real * real) >> 33);
 111     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
 112     /* store the result in 3.29 format in the destination buffer. */
 113     *pDst++ = acc0 + acc1;
 114
 115     /* Decrement the loop counter */
 116     blkCnt--;
 117   }
 118
 119   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.
 120    ** No loop unrolling is used. */
 121   blkCnt = numSamples % 0x4u;
 122
 123   while(blkCnt > 0u)
 124   {
 125     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
 126     real = *pSrc++;
 127     imag = *pSrc++;
 128     acc0 = (q31_t) (((q63_t) real * real) >> 33);
 129     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
 130     /* store the result in 3.29 format in the destination buffer. */
 131     *pDst++ = acc0 + acc1;
 132
 133     /* Decrement the loop counter */
 134     blkCnt--;
 135   }
 136
 137 #else
 138
 139   /* Run the below code for Cortex-M0 */
 140
 141   while(numSamples > 0u)
 142   {
 143     /* out = ((real * real) + (imag * imag)) */
 144     real = *pSrc++;
 145     imag = *pSrc++;
 146     acc0 = (q31_t) (((q63_t) real * real) >> 33);
 147     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
 148     /* store the result in 3.29 format in the destination buffer. */
 149     *pDst++ = acc0 + acc1;
 150
 151     /* Decrement the loop counter */
 152     numSamples--;
 153   }
 154
 155 #endif /* #ifndef ARM_MATH_CM0_FAMILY */
 156
 157 }
 158
 159 /**
 160  * @} end of cmplx_mag_squared group
 161  */