tmk_core/tool/mbed/mbed-sdk/libraries/dsp/cmsis_dsp/ComplexMathFunctions/arm_cmplx_mag_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_q31.c
   9 *
  10 * Description:  Q31 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  * @addtogroup cmplx_mag
  49  * @{
  50  */
  51
  52 /**
  53  * @brief  Q31 complex magnitude
  54  * @param  *pSrc points to the complex input vector
  55  * @param  *pDst points to the real output vector
  56  * @param  numSamples number of complex samples in the input vector
  57  * @return none.
  58  *
  59  * <b>Scaling and Overflow Behavior:</b>
  60  * \par
  61  * The function implements 1.31 by 1.31 multiplications and finally output is converted into 2.30 format.
  62  * Input down scaling is not required.
  63  */
  64
  65 void arm_cmplx_mag_q31(
  66   q31_t * pSrc,
  67   q31_t * pDst,
  68   uint32_t numSamples)
  69 {
  70   q31_t real, imag;                              /* Temporary variables to hold input values */
  71   q31_t acc0, acc1;                              /* Accumulators */
  72   uint32_t blkCnt;                               /* loop counter */
  73
  74 #ifndef ARM_MATH_CM0_FAMILY
  75
  76   /* Run the below code for Cortex-M4 and Cortex-M3 */
  77   q31_t real1, real2, imag1, imag2;              /* Temporary variables to hold input values */
  78   q31_t out1, out2, out3, out4;                  /* Accumulators */
  79   q63_t mul1, mul2, mul3, mul4;                  /* Temporary variables */
  80
  81
  82   /*loop Unrolling */
  83   blkCnt = numSamples >> 2u;
  84
  85   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.
  86    ** a second loop below computes the remaining 1 to 3 samples. */
  87   while(blkCnt > 0u)
  88   {
  89     /* read complex input from source buffer */
  90     real1 = pSrc[0];
  91     imag1 = pSrc[1];
  92     real2 = pSrc[2];
  93     imag2 = pSrc[3];
  94
  95     /* calculate power of input values */
  96     mul1 = (q63_t) real1 *real1;
  97     mul2 = (q63_t) imag1 *imag1;
  98     mul3 = (q63_t) real2 *real2;
  99     mul4 = (q63_t) imag2 *imag2;
 100
 101     /* get the result to 3.29 format */
 102     out1 = (q31_t) (mul1 >> 33);
 103     out2 = (q31_t) (mul2 >> 33);
 104     out3 = (q31_t) (mul3 >> 33);
 105     out4 = (q31_t) (mul4 >> 33);
 106
 107     /* add real and imaginary accumulators */
 108     out1 = out1 + out2;
 109     out3 = out3 + out4;
 110
 111     /* read complex input from source buffer */
 112     real1 = pSrc[4];
 113     imag1 = pSrc[5];
 114     real2 = pSrc[6];
 115     imag2 = pSrc[7];
 116
 117     /* calculate square root */
 118     arm_sqrt_q31(out1, &pDst[0]);
 119
 120     /* calculate power of input values */
 121     mul1 = (q63_t) real1 *real1;
 122
 123     /* calculate square root */
 124     arm_sqrt_q31(out3, &pDst[1]);
 125
 126     /* calculate power of input values */
 127     mul2 = (q63_t) imag1 *imag1;
 128     mul3 = (q63_t) real2 *real2;
 129     mul4 = (q63_t) imag2 *imag2;
 130
 131     /* get the result to 3.29 format */
 132     out1 = (q31_t) (mul1 >> 33);
 133     out2 = (q31_t) (mul2 >> 33);
 134     out3 = (q31_t) (mul3 >> 33);
 135     out4 = (q31_t) (mul4 >> 33);
 136
 137     /* add real and imaginary accumulators */
 138     out1 = out1 + out2;
 139     out3 = out3 + out4;
 140
 141     /* calculate square root */
 142     arm_sqrt_q31(out1, &pDst[2]);
 143
 144     /* increment destination by 8 to process next samples */
 145     pSrc += 8u;
 146
 147     /* calculate square root */
 148     arm_sqrt_q31(out3, &pDst[3]);
 149
 150     /* increment destination by 4 to process next samples */
 151     pDst += 4u;
 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     /* C[0] = sqrt(A[0] * A[0] + A[1] * A[1]) */
 171     real = *pSrc++;
 172     imag = *pSrc++;
 173     acc0 = (q31_t) (((q63_t) real * real) >> 33);
 174     acc1 = (q31_t) (((q63_t) imag * imag) >> 33);
 175     /* store the result in 2.30 format in the destination buffer. */
 176     arm_sqrt_q31(acc0 + acc1, pDst++);
 177
 178     /* Decrement the loop counter */
 179     blkCnt--;
 180   }
 181 }
 182
 183 /**
 184  * @} end of cmplx_mag group
 185  */