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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_f32.c    
  9. *    
  10. * Description:  Floating-point 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. #include "arm_math.h"
  41.  
  42. /**        
  43.  * @ingroup groupCmplxMath        
  44.  */
  45.  
  46. /**        
  47.  * @defgroup cmplx_mag_squared Complex Magnitude Squared        
  48.  *        
  49.  * Computes the magnitude squared of 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.  * in the input array and the data is stored in an interleaved fashion        
  55.  * (real, imag, real, imag, ...).        
  56.  * The input array has a total of <code>2*numSamples</code> values;        
  57.  * the output array has a total of <code>numSamples</code> values.        
  58.  *        
  59.  * The underlying algorithm is used:        
  60.  *        
  61.  * <pre>        
  62.  * for(n=0; n<numSamples; n++) {        
  63.  *     pDst[n] = pSrc[(2*n)+0]^2 + pSrc[(2*n)+1]^2;        
  64.  * }        
  65.  * </pre>        
  66.  *        
  67.  * There are separate functions for floating-point, Q15, and Q31 data types.        
  68.  */
  69.  
  70. /**        
  71.  * @addtogroup cmplx_mag_squared        
  72.  * @{        
  73.  */
  74.  
  75.  
  76. /**        
  77.  * @brief  Floating-point complex magnitude squared        
  78.  * @param[in]  *pSrc points to the complex input vector        
  79.  * @param[out]  *pDst points to the real output vector        
  80.  * @param[in]  numSamples number of complex samples in the input vector        
  81.  * @return none.        
  82.  */
  83.  
  84. void arm_cmplx_mag_squared_f32(
  85.   float32_t * pSrc,
  86.   float32_t * pDst,
  87.   uint32_t numSamples)
  88. {
  89.   float32_t real, imag;                          /* Temporary variables to store real and imaginary values */
  90.   uint32_t blkCnt;                               /* loop counter */
  91.  
  92. #ifndef ARM_MATH_CM0_FAMILY
  93.   float32_t real1, real2, real3, real4;          /* Temporary variables to hold real values */
  94.   float32_t imag1, imag2, imag3, imag4;          /* Temporary variables to hold imaginary values */
  95.   float32_t mul1, mul2, mul3, mul4;              /* Temporary variables */
  96.   float32_t mul5, mul6, mul7, mul8;              /* Temporary variables */
  97.   float32_t out1, out2, out3, out4;              /* Temporary variables to hold output values */
  98.  
  99.   /*loop Unrolling */
  100.   blkCnt = numSamples >> 2u;
  101.  
  102.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.        
  103.    ** a second loop below computes the remaining 1 to 3 samples. */
  104.   while(blkCnt > 0u)
  105.   {
  106.     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
  107.     /* read real input sample from source buffer */
  108.     real1 = pSrc[0];
  109.     /* read imaginary input sample from source buffer */
  110.     imag1 = pSrc[1];
  111.  
  112.     /* calculate power of real value */
  113.     mul1 = real1 * real1;
  114.  
  115.     /* read real input sample from source buffer */
  116.     real2 = pSrc[2];
  117.  
  118.     /* calculate power of imaginary value */
  119.     mul2 = imag1 * imag1;
  120.  
  121.     /* read imaginary input sample from source buffer */
  122.     imag2 = pSrc[3];
  123.  
  124.     /* calculate power of real value */
  125.     mul3 = real2 * real2;
  126.  
  127.     /* read real input sample from source buffer */
  128.     real3 = pSrc[4];
  129.  
  130.     /* calculate power of imaginary value */
  131.     mul4 = imag2 * imag2;
  132.  
  133.     /* read imaginary input sample from source buffer */
  134.     imag3 = pSrc[5];
  135.  
  136.     /* calculate power of real value */
  137.     mul5 = real3 * real3;
  138.     /* calculate power of imaginary value */
  139.     mul6 = imag3 * imag3;
  140.  
  141.     /* read real input sample from source buffer */
  142.     real4 = pSrc[6];
  143.  
  144.     /* accumulate real and imaginary powers */
  145.     out1 = mul1 + mul2;
  146.  
  147.     /* read imaginary input sample from source buffer */
  148.     imag4 = pSrc[7];
  149.  
  150.     /* accumulate real and imaginary powers */
  151.     out2 = mul3 + mul4;
  152.  
  153.     /* calculate power of real value */
  154.     mul7 = real4 * real4;
  155.     /* calculate power of imaginary value */
  156.     mul8 = imag4 * imag4;
  157.  
  158.     /* store output to destination */
  159.     pDst[0] = out1;
  160.  
  161.     /* accumulate real and imaginary powers */
  162.     out3 = mul5 + mul6;
  163.  
  164.     /* store output to destination */
  165.     pDst[1] = out2;
  166.  
  167.     /* accumulate real and imaginary powers */
  168.     out4 = mul7 + mul8;
  169.  
  170.     /* store output to destination */
  171.     pDst[2] = out3;
  172.  
  173.     /* increment destination pointer by 8 to process next samples */
  174.     pSrc += 8u;
  175.  
  176.     /* store output to destination */
  177.     pDst[3] = out4;
  178.  
  179.     /* increment destination pointer by 4 to process next samples */
  180.     pDst += 4u;
  181.  
  182.     /* Decrement the loop counter */
  183.     blkCnt--;
  184.   }
  185.  
  186.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.        
  187.    ** No loop unrolling is used. */
  188.   blkCnt = numSamples % 0x4u;
  189.  
  190. #else
  191.  
  192.   /* Run the below code for Cortex-M0 */
  193.  
  194.   blkCnt = numSamples;
  195.  
  196. #endif /* #ifndef ARM_MATH_CM0_FAMILY */
  197.  
  198.   while(blkCnt > 0u)
  199.   {
  200.     /* C[0] = (A[0] * A[0] + A[1] * A[1]) */
  201.     real = *pSrc++;
  202.     imag = *pSrc++;
  203.  
  204.     /* out = (real * real) + (imag * imag) */
  205.     /* store the result in the destination buffer. */
  206.     *pDst++ = (real * real) + (imag * imag);
  207.  
  208.     /* Decrement the loop counter */
  209.     blkCnt--;
  210.   }
  211. }
  212.  
  213. /**        
  214.  * @} end of cmplx_mag_squared group        
  215.  */
  216.