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  1. /* ----------------------------------------------------------------------    
  2. * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
  3. *    
  4. * $Date:        19. March 2015
  5. * $Revision:    V.1.4.5
  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.  */
  162.