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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_q31.c    
  9. *    
  10. * Description:  Q31 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.  * @addtogroup cmplx_conj        
  48.  * @{        
  49.  */
  50.  
  51. /**        
  52.  * @brief  Q31 complex conjugate.        
  53.  * @param  *pSrc points to the input vector        
  54.  * @param  *pDst points to the output vector        
  55.  * @param  numSamples number of complex samples in each vector        
  56.  * @return none.        
  57.  *        
  58.  * <b>Scaling and Overflow Behavior:</b>        
  59.  * \par        
  60.  * The function uses saturating arithmetic.        
  61.  * The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.        
  62.  */
  63.  
  64. void arm_cmplx_conj_q31(
  65.   q31_t * pSrc,
  66.   q31_t * pDst,
  67.   uint32_t numSamples)
  68. {
  69.   uint32_t blkCnt;                               /* loop counter */
  70.   q31_t in;                                      /* Input value */
  71.  
  72. #ifndef ARM_MATH_CM0_FAMILY
  73.  
  74.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  75.   q31_t inR1, inR2, inR3, inR4;                  /* Temporary real variables */
  76.   q31_t inI1, inI2, inI3, inI4;                  /* Temporary imaginary variables */
  77.  
  78.   /*loop Unrolling */
  79.   blkCnt = numSamples >> 2u;
  80.  
  81.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.        
  82.    ** a second loop below computes the remaining 1 to 3 samples. */
  83.   while(blkCnt > 0u)
  84.   {
  85.     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
  86.     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
  87.     /* Saturated to 0x7fffffff if the input is -1(0x80000000) */
  88.     /* read real input sample */
  89.     inR1 = pSrc[0];
  90.     /* store real input sample */
  91.     pDst[0] = inR1;
  92.  
  93.     /* read imaginary input sample */
  94.     inI1 = pSrc[1];
  95.  
  96.     /* read real input sample */
  97.     inR2 = pSrc[2];
  98.     /* store real input sample */
  99.     pDst[2] = inR2;
  100.  
  101.     /* read imaginary input sample */
  102.     inI2 = pSrc[3];
  103.  
  104.     /* negate imaginary input sample */
  105.     inI1 = __QSUB(0, inI1);
  106.  
  107.     /* read real input sample */
  108.     inR3 = pSrc[4];
  109.     /* store real input sample */
  110.     pDst[4] = inR3;
  111.  
  112.     /* read imaginary input sample */
  113.     inI3 = pSrc[5];
  114.  
  115.     /* negate imaginary input sample */
  116.     inI2 = __QSUB(0, inI2);
  117.  
  118.     /* read real input sample */
  119.     inR4 = pSrc[6];
  120.     /* store real input sample */
  121.     pDst[6] = inR4;
  122.  
  123.     /* negate imaginary input sample */
  124.     inI3 = __QSUB(0, inI3);
  125.  
  126.     /* store imaginary input sample */
  127.     inI4 = pSrc[7];
  128.  
  129.     /* store imaginary input samples */
  130.     pDst[1] = inI1;
  131.  
  132.     /* negate imaginary input sample */
  133.     inI4 = __QSUB(0, inI4);
  134.  
  135.     /* store imaginary input samples */
  136.     pDst[3] = inI2;
  137.  
  138.     /* increment source pointer by 8 to proecess next samples */
  139.     pSrc += 8u;
  140.  
  141.     /* store imaginary input samples */
  142.     pDst[5] = inI3;
  143.     pDst[7] = inI4;
  144.  
  145.     /* increment destination pointer by 8 to process next samples */
  146.     pDst += 8u;
  147.  
  148.     /* Decrement the loop counter */
  149.     blkCnt--;
  150.   }
  151.  
  152.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.        
  153.    ** No loop unrolling is used. */
  154.   blkCnt = numSamples % 0x4u;
  155.  
  156. #else
  157.  
  158.   /* Run the below code for Cortex-M0 */
  159.   blkCnt = numSamples;
  160.  
  161.  
  162. #endif /* #ifndef ARM_MATH_CM0_FAMILY */
  163.  
  164.   while(blkCnt > 0u)
  165.   {
  166.     /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
  167.     /* Calculate Complex Conjugate and then store the results in the destination buffer. */
  168.     /* Saturated to 0x7fffffff if the input is -1(0x80000000) */
  169.     *pDst++ = *pSrc++;
  170.     in = *pSrc++;
  171.     *pDst++ = (in == INT32_MIN) ? INT32_MAX : -in;
  172.  
  173.     /* Decrement the loop counter */
  174.     blkCnt--;
  175.   }
  176. }
  177.  
  178. /**        
  179.  * @} end of cmplx_conj group        
  180.  */
  181.