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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_real_q31.c    
  9. *    
  10. * Description:  Q31 complex by real 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 CmplxByRealMult    
  49.  * @{    
  50.  */
  51.  
  52.  
  53. /**    
  54.  * @brief  Q31 complex-by-real multiplication    
  55.  * @param[in]  *pSrcCmplx points to the complex input vector    
  56.  * @param[in]  *pSrcReal points to the real input vector    
  57.  * @param[out]  *pCmplxDst points to the complex output vector    
  58.  * @param[in]  numSamples number of samples in each vector    
  59.  * @return none.    
  60.  *    
  61.  * <b>Scaling and Overflow Behavior:</b>    
  62.  * \par    
  63.  * The function uses saturating arithmetic.    
  64.  * Results outside of the allowable Q31 range[0x80000000 0x7FFFFFFF] will be saturated.    
  65.  */
  66.  
  67. void arm_cmplx_mult_real_q31(
  68.   q31_t * pSrcCmplx,
  69.   q31_t * pSrcReal,
  70.   q31_t * pCmplxDst,
  71.   uint32_t numSamples)
  72. {
  73.   q31_t inA1;                                    /* Temporary variable to store input value */
  74.  
  75. #ifndef ARM_MATH_CM0_FAMILY
  76.  
  77.   /* Run the below code for Cortex-M4 and Cortex-M3 */
  78.   uint32_t blkCnt;                               /* loop counters */
  79.   q31_t inA2, inA3, inA4;                        /* Temporary variables to hold input data */
  80.   q31_t inB1, inB2;                              /* Temporary variabels to hold input data */
  81.   q31_t out1, out2, out3, out4;                  /* Temporary variables to hold output data */
  82.  
  83.   /* loop Unrolling */
  84.   blkCnt = numSamples >> 2u;
  85.  
  86.   /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
  87.    ** a second loop below computes the remaining 1 to 3 samples. */
  88.   while(blkCnt > 0u)
  89.   {
  90.     /* C[2 * i] = A[2 * i] * B[i].            */
  91.     /* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
  92.     /* read real input from complex input buffer */
  93.     inA1 = *pSrcCmplx++;
  94.     inA2 = *pSrcCmplx++;
  95.     /* read input from real input bufer */
  96.     inB1 = *pSrcReal++;
  97.     inB2 = *pSrcReal++;
  98.     /* read imaginary input from complex input buffer */
  99.     inA3 = *pSrcCmplx++;
  100.     inA4 = *pSrcCmplx++;
  101.  
  102.     /* multiply complex input with real input */
  103.     out1 = ((q63_t) inA1 * inB1) >> 32;
  104.     out2 = ((q63_t) inA2 * inB1) >> 32;
  105.     out3 = ((q63_t) inA3 * inB2) >> 32;
  106.     out4 = ((q63_t) inA4 * inB2) >> 32;
  107.  
  108.     /* sature the result */
  109.     out1 = __SSAT(out1, 31);
  110.     out2 = __SSAT(out2, 31);
  111.     out3 = __SSAT(out3, 31);
  112.     out4 = __SSAT(out4, 31);
  113.  
  114.     /* get result in 1.31 format */
  115.     out1 = out1 << 1;
  116.     out2 = out2 << 1;
  117.     out3 = out3 << 1;
  118.     out4 = out4 << 1;
  119.  
  120.     /* store the result to destination buffer */
  121.     *pCmplxDst++ = out1;
  122.     *pCmplxDst++ = out2;
  123.     *pCmplxDst++ = out3;
  124.     *pCmplxDst++ = out4;
  125.  
  126.     /* read real input from complex input buffer */
  127.     inA1 = *pSrcCmplx++;
  128.     inA2 = *pSrcCmplx++;
  129.     /* read input from real input bufer */
  130.     inB1 = *pSrcReal++;
  131.     inB2 = *pSrcReal++;
  132.     /* read imaginary input from complex input buffer */
  133.     inA3 = *pSrcCmplx++;
  134.     inA4 = *pSrcCmplx++;
  135.  
  136.     /* multiply complex input with real input */
  137.     out1 = ((q63_t) inA1 * inB1) >> 32;
  138.     out2 = ((q63_t) inA2 * inB1) >> 32;
  139.     out3 = ((q63_t) inA3 * inB2) >> 32;
  140.     out4 = ((q63_t) inA4 * inB2) >> 32;
  141.  
  142.     /* sature the result */
  143.     out1 = __SSAT(out1, 31);
  144.     out2 = __SSAT(out2, 31);
  145.     out3 = __SSAT(out3, 31);
  146.     out4 = __SSAT(out4, 31);
  147.  
  148.     /* get result in 1.31 format */
  149.     out1 = out1 << 1;
  150.     out2 = out2 << 1;
  151.     out3 = out3 << 1;
  152.     out4 = out4 << 1;
  153.  
  154.     /* store the result to destination buffer */
  155.     *pCmplxDst++ = out1;
  156.     *pCmplxDst++ = out2;
  157.     *pCmplxDst++ = out3;
  158.     *pCmplxDst++ = out4;
  159.  
  160.     /* Decrement the numSamples loop counter */
  161.     blkCnt--;
  162.   }
  163.  
  164.   /* If the numSamples is not a multiple of 4, compute any remaining output samples here.    
  165.    ** No loop unrolling is used. */
  166.   blkCnt = numSamples % 0x4u;
  167.  
  168.   while(blkCnt > 0u)
  169.   {
  170.     /* C[2 * i] = A[2 * i] * B[i].            */
  171.     /* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
  172.     /* read real input from complex input buffer */
  173.     inA1 = *pSrcCmplx++;
  174.     inA2 = *pSrcCmplx++;
  175.     /* read input from real input bufer */
  176.     inB1 = *pSrcReal++;
  177.  
  178.     /* multiply complex input with real input */
  179.     out1 = ((q63_t) inA1 * inB1) >> 32;
  180.     out2 = ((q63_t) inA2 * inB1) >> 32;
  181.  
  182.     /* sature the result */
  183.     out1 = __SSAT(out1, 31);
  184.     out2 = __SSAT(out2, 31);
  185.  
  186.     /* get result in 1.31 format */
  187.     out1 = out1 << 1;
  188.     out2 = out2 << 1;
  189.  
  190.     /* store the result to destination buffer */
  191.     *pCmplxDst++ = out1;
  192.     *pCmplxDst++ = out2;
  193.  
  194.     /* Decrement the numSamples loop counter */
  195.     blkCnt--;
  196.   }
  197.  
  198. #else
  199.  
  200.   /* Run the below code for Cortex-M0 */
  201.  
  202.   while(numSamples > 0u)
  203.   {
  204.     /* realOut = realA * realB.            */
  205.     /* imagReal = imagA * realB.               */
  206.     inA1 = *pSrcReal++;
  207.     /* store the result in the destination buffer. */
  208.     *pCmplxDst++ =
  209.       (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
  210.     *pCmplxDst++ =
  211.       (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
  212.  
  213.     /* Decrement the numSamples loop counter */
  214.     numSamples--;
  215.   }
  216.  
  217. #endif /* #ifndef ARM_MATH_CM0_FAMILY */
  218.  
  219. }
  220.  
  221. /**    
  222.  * @} end of CmplxByRealMult group    
  223.  */
  224.