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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_mult_cmplx_q15.c    
  9. *    
  10. * Description:  Q15 complex-by-complex multiplication    
  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 CmplxByCmplxMult    
  49.  * @{    
  50.  */
  51.  
  52. /**    
  53.  * @brief  Q15 complex-by-complex multiplication    
  54.  * @param[in]  *pSrcA points to the first input vector    
  55.  * @param[in]  *pSrcB points to the second input vector    
  56.  * @param[out]  *pDst  points to the output vector    
  57.  * @param[in]  numSamples number of complex samples in each vector    
  58.  * @return none.    
  59.  *    
  60.  * <b>Scaling and Overflow Behavior:</b>    
  61.  * \par    
  62.  * The function implements 1.15 by 1.15 multiplications and finally output is converted into 3.13 format.    
  63.  */
  64.  
  65. void arm_cmplx_mult_cmplx_q15(
  66.   q15_t * pSrcA,
  67.   q15_t * pSrcB,
  68.   q15_t * pDst,
  69.   uint32_t numSamples)
  70. {
  71.   q15_t a, b, c, d;                              /* Temporary variables to store real and imaginary values */
  72.  
  73. #ifndef ARM_MATH_CM0_FAMILY
  74.  
  75.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  76.   uint32_t blkCnt;                               /* loop counters */
  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[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
  86.     /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
  87.     a = *pSrcA++;
  88.     b = *pSrcA++;
  89.     c = *pSrcB++;
  90.     d = *pSrcB++;
  91.  
  92.     /* store the result in 3.13 format in the destination buffer. */
  93.     *pDst++ =
  94.       (q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
  95.     /* store the result in 3.13 format in the destination buffer. */
  96.     *pDst++ =
  97.       (q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
  98.  
  99.     a = *pSrcA++;
  100.     b = *pSrcA++;
  101.     c = *pSrcB++;
  102.     d = *pSrcB++;
  103.  
  104.     /* store the result in 3.13 format in the destination buffer. */
  105.     *pDst++ =
  106.       (q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
  107.     /* store the result in 3.13 format in the destination buffer. */
  108.     *pDst++ =
  109.       (q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
  110.  
  111.     a = *pSrcA++;
  112.     b = *pSrcA++;
  113.     c = *pSrcB++;
  114.     d = *pSrcB++;
  115.  
  116.     /* store the result in 3.13 format in the destination buffer. */
  117.     *pDst++ =
  118.       (q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
  119.     /* store the result in 3.13 format in the destination buffer. */
  120.     *pDst++ =
  121.       (q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
  122.  
  123.     a = *pSrcA++;
  124.     b = *pSrcA++;
  125.     c = *pSrcB++;
  126.     d = *pSrcB++;
  127.  
  128.     /* store the result in 3.13 format in the destination buffer. */
  129.     *pDst++ =
  130.       (q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
  131.     /* store the result in 3.13 format in the destination buffer. */
  132.     *pDst++ =
  133.       (q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
  134.  
  135.     /* Decrement the blockSize loop counter */
  136.     blkCnt--;
  137.   }
  138.  
  139.   /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
  140.    ** No loop unrolling is used. */
  141.   blkCnt = numSamples % 0x4u;
  142.  
  143.   while(blkCnt > 0u)
  144.   {
  145.     /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
  146.     /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
  147.     a = *pSrcA++;
  148.     b = *pSrcA++;
  149.     c = *pSrcB++;
  150.     d = *pSrcB++;
  151.  
  152.     /* store the result in 3.13 format in the destination buffer. */
  153.     *pDst++ =
  154.       (q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
  155.     /* store the result in 3.13 format in the destination buffer. */
  156.     *pDst++ =
  157.       (q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
  158.  
  159.     /* Decrement the blockSize loop counter */
  160.     blkCnt--;
  161.   }
  162.  
  163. #else
  164.  
  165.   /* Run the below code for Cortex-M0 */
  166.  
  167.   while(numSamples > 0u)
  168.   {
  169.     /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
  170.     /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
  171.     a = *pSrcA++;
  172.     b = *pSrcA++;
  173.     c = *pSrcB++;
  174.     d = *pSrcB++;
  175.  
  176.     /* store the result in 3.13 format in the destination buffer. */
  177.     *pDst++ =
  178.       (q15_t) (q31_t) (((q31_t) a * c) >> 17) - (((q31_t) b * d) >> 17);
  179.     /* store the result in 3.13 format in the destination buffer. */
  180.     *pDst++ =
  181.       (q15_t) (q31_t) (((q31_t) a * d) >> 17) + (((q31_t) b * c) >> 17);
  182.  
  183.     /* Decrement the blockSize loop counter */
  184.     numSamples--;
  185.   }
  186.  
  187. #endif /* #ifndef ARM_MATH_CM0_FAMILY */
  188.  
  189. }
  190.  
  191. /**    
  192.  * @} end of CmplxByCmplxMult group    
  193.  */
  194.