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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_conj_f32.c    
  9. *    
  10. * Description:  Floating-point 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.  * @defgroup cmplx_conj Complex Conjugate        
  48.  *        
  49.  * Conjugates 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.  * and the data in each array is stored in an interleaved fashion        
  55.  * (real, imag, real, imag, ...).        
  56.  * Each array has a total of <code>2*numSamples</code> values.        
  57.  * The underlying algorithm is used:        
  58.  *        
  59.  * <pre>        
  60.  * for(n=0; n<numSamples; n++) {        
  61.  *     pDst[(2*n)+0)] = pSrc[(2*n)+0];     // real part        
  62.  *     pDst[(2*n)+1)] = -pSrc[(2*n)+1];    // imag part        
  63.  * }        
  64.  * </pre>        
  65.  *        
  66.  * There are separate functions for floating-point, Q15, and Q31 data types.        
  67.  */
  68.  
  69. /**        
  70.  * @addtogroup cmplx_conj        
  71.  * @{        
  72.  */
  73.  
  74. /**        
  75.  * @brief  Floating-point complex conjugate.        
  76.  * @param  *pSrc points to the input vector        
  77.  * @param  *pDst points to the output vector        
  78.  * @param  numSamples number of complex samples in each vector        
  79.  * @return none.        
  80.  */
  81.  
  82. void arm_cmplx_conj_f32(
  83.   float32_t * pSrc,
  84.   float32_t * pDst,
  85.   uint32_t numSamples)
  86. {
  87.   uint32_t blkCnt;                               /* loop counter */
  88.  
  89. #ifndef ARM_MATH_CM0_FAMILY
  90.  
  91.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  92.   float32_t inR1, inR2, inR3, inR4;
  93.   float32_t inI1, inI2, inI3, inI4;
  94.  
  95.   /*loop Unrolling */
  96.   blkCnt = numSamples >> 2u;
  97.  
  98.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.        
  99.    ** a second loop below computes the remaining 1 to 3 samples. */
  100.   while(blkCnt > 0u)
  101.   {
  102.     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
  103.     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
  104.     /* read real input samples */
  105.     inR1 = pSrc[0];
  106.     /* store real samples to destination */
  107.     pDst[0] = inR1;
  108.     inR2 = pSrc[2];
  109.     pDst[2] = inR2;
  110.     inR3 = pSrc[4];
  111.     pDst[4] = inR3;
  112.     inR4 = pSrc[6];
  113.     pDst[6] = inR4;
  114.  
  115.     /* read imaginary input samples */
  116.     inI1 = pSrc[1];
  117.     inI2 = pSrc[3];
  118.  
  119.     /* conjugate input */
  120.     inI1 = -inI1;
  121.  
  122.     /* read imaginary input samples */
  123.     inI3 = pSrc[5];
  124.  
  125.     /* conjugate input */
  126.     inI2 = -inI2;
  127.  
  128.     /* read imaginary input samples */
  129.     inI4 = pSrc[7];
  130.  
  131.     /* conjugate input */
  132.     inI3 = -inI3;
  133.  
  134.     /* store imaginary samples to destination */
  135.     pDst[1] = inI1;
  136.     pDst[3] = inI2;
  137.  
  138.     /* conjugate input */
  139.     inI4 = -inI4;
  140.  
  141.     /* store imaginary samples to destination */
  142.     pDst[5] = inI3;
  143.  
  144.     /* increment source pointer by 8 to process next sampels */
  145.     pSrc += 8u;
  146.  
  147.     /* store imaginary sample to destination */
  148.     pDst[7] = inI4;
  149.  
  150.     /* increment destination pointer by 8 to store next samples */
  151.     pDst += 8u;
  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.     /* realOut + j (imagOut) = realIn + j (-1) imagIn */
  171.     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
  172.     *pDst++ = *pSrc++;
  173.     *pDst++ = -*pSrc++;
  174.  
  175.     /* Decrement the loop counter */
  176.     blkCnt--;
  177.   }
  178. }
  179.  
  180. /**        
  181.  * @} end of cmplx_conj group        
  182.  */
  183.