text: /* ----------------------------------------------------------------------    
  * Copyright (C) 2010 ARM Limited. All rights reserved.    
  *    
  * $Date:        15. February 2012  
  * $Revision: 	V1.1.0  
  *    
  * Project: 	    CMSIS DSP Library    
  * Title:	    arm_cmplx_mult_cmplx_q31.c    
  *    
  * Description:	Q31 complex-by-complex multiplication    
  *    
  * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  *  
  * Version 1.1.0 2012/02/15 
  *    Updated with more optimizations, bug fixes and minor API changes.  
  *   
  * Version 1.0.10 2011/7/15  
  *    Big Endian support added and Merged M0 and M3/M4 Source code.   
  *    
  * Version 1.0.3 2010/11/29   
  *    Re-organized the CMSIS folders and updated documentation.    
  *     
  * Version 1.0.2 2010/11/11    
  *    Documentation updated.     
  *    
  * Version 1.0.1 2010/10/05     
  *    Production release and review comments incorporated.    
  *    
  * Version 1.0.0 2010/09/20     
  *    Production release and review comments incorporated.    
  * -------------------------------------------------------------------- */
  
  #include "arm_math.h"
  
  /**    
   * @ingroup groupCmplxMath    
   */
  
  /**    
   * @addtogroup CmplxByCmplxMult    
   * @{    
   */
  
  
  /**    
   * @brief  Q31 complex-by-complex multiplication    
   * @param[in]  *pSrcA points to the first input vector    
   * @param[in]  *pSrcB points to the second input vector    
   * @param[out]  *pDst  points to the output vector    
   * @param[in]  numSamples number of complex samples in each vector    
   * @return none.    
   *    
   * <b>Scaling and Overflow Behavior:</b>    
   * \par    
   * The function implements 1.31 by 1.31 multiplications and finally output is converted into 3.29 format.    
   * Input down scaling is not required.    
   */
  
  void arm_cmplx_mult_cmplx_q31(
    q31_t * pSrcA,
    q31_t * pSrcB,
    q31_t * pDst,
    uint32_t numSamples)
  {
    q31_t a, b, c, d;                              /* Temporary variables to store real and imaginary values */
    uint32_t blkCnt;                               /* loop counters */
    q31_t mul1, mul2, mul3, mul4;
    q31_t out1, out2;
  
  #ifndef ARM_MATH_CM0
  
    /* Run the below code for Cortex-M4 and Cortex-M3 */
  
    /* loop Unrolling */
    blkCnt = numSamples >> 2u;
  
    /* First part of the processing with loop unrolling.  Compute 4 outputs at a time.    
     ** a second loop below computes the remaining 1 to 3 samples. */
    while(blkCnt > 0u)
    {
      /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
      /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
      a = *pSrcA++;
      b = *pSrcA++;
      c = *pSrcB++;
      d = *pSrcB++;
  
      mul1 = (q31_t) (((q63_t) a * c) >> 32);
      mul2 = (q31_t) (((q63_t) b * d) >> 32);
      mul3 = (q31_t) (((q63_t) a * d) >> 32);
      mul4 = (q31_t) (((q63_t) b * c) >> 32);
  
      mul1 = (mul1 >> 1);
      mul2 = (mul2 >> 1);
      mul3 = (mul3 >> 1);
      mul4 = (mul4 >> 1);
  
      out1 = mul1 - mul2;
      out2 = mul3 + mul4;
  
      /* store the real result in 3.29 format in the destination buffer. */
      *pDst++ = out1;
      /* store the imag result in 3.29 format in the destination buffer. */
      *pDst++ = out2;
  
      a = *pSrcA++;
      b = *pSrcA++;
      c = *pSrcB++;
      d = *pSrcB++;
  
      mul1 = (q31_t) (((q63_t) a * c) >> 32);
      mul2 = (q31_t) (((q63_t) b * d) >> 32);
      mul3 = (q31_t) (((q63_t) a * d) >> 32);
      mul4 = (q31_t) (((q63_t) b * c) >> 32);
  
      mul1 = (mul1 >> 1);
      mul2 = (mul2 >> 1);
      mul3 = (mul3 >> 1);
      mul4 = (mul4 >> 1);
  
      out1 = mul1 - mul2;
      out2 = mul3 + mul4;
  
      /* store the real result in 3.29 format in the destination buffer. */
      *pDst++ = out1;
      /* store the imag result in 3.29 format in the destination buffer. */
      *pDst++ = out2;
  
      a = *pSrcA++;
      b = *pSrcA++;
      c = *pSrcB++;
      d = *pSrcB++;
  
      mul1 = (q31_t) (((q63_t) a * c) >> 32);
      mul2 = (q31_t) (((q63_t) b * d) >> 32);
      mul3 = (q31_t) (((q63_t) a * d) >> 32);
      mul4 = (q31_t) (((q63_t) b * c) >> 32);
  
      mul1 = (mul1 >> 1);
      mul2 = (mul2 >> 1);
      mul3 = (mul3 >> 1);
      mul4 = (mul4 >> 1);
  
      out1 = mul1 - mul2;
      out2 = mul3 + mul4;
  
      /* store the real result in 3.29 format in the destination buffer. */
      *pDst++ = out1;
      /* store the imag result in 3.29 format in the destination buffer. */
      *pDst++ = out2;
  
      a = *pSrcA++;
      b = *pSrcA++;
      c = *pSrcB++;
      d = *pSrcB++;
  
      mul1 = (q31_t) (((q63_t) a * c) >> 32);
      mul2 = (q31_t) (((q63_t) b * d) >> 32);
      mul3 = (q31_t) (((q63_t) a * d) >> 32);
      mul4 = (q31_t) (((q63_t) b * c) >> 32);
  
      mul1 = (mul1 >> 1);
      mul2 = (mul2 >> 1);
      mul3 = (mul3 >> 1);
      mul4 = (mul4 >> 1);
  
      out1 = mul1 - mul2;
      out2 = mul3 + mul4;
  
      /* store the real result in 3.29 format in the destination buffer. */
      *pDst++ = out1;
      /* store the imag result in 3.29 format in the destination buffer. */
      *pDst++ = out2;
  
      /* Decrement the blockSize loop counter */
      blkCnt--;
    }
  
    /* If the blockSize is not a multiple of 4, compute any remaining output samples here.    
     ** No loop unrolling is used. */
    blkCnt = numSamples % 0x4u;
  
    while(blkCnt > 0u)
    {
      /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
      /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
      a = *pSrcA++;
      b = *pSrcA++;
      c = *pSrcB++;
      d = *pSrcB++;
  
      mul1 = (q31_t) (((q63_t) a * c) >> 32);
      mul2 = (q31_t) (((q63_t) b * d) >> 32);
      mul3 = (q31_t) (((q63_t) a * d) >> 32);
      mul4 = (q31_t) (((q63_t) b * c) >> 32);
  
      mul1 = (mul1 >> 1);
      mul2 = (mul2 >> 1);
      mul3 = (mul3 >> 1);
      mul4 = (mul4 >> 1);
  
      out1 = mul1 - mul2;
      out2 = mul3 + mul4;
  
      /* store the real result in 3.29 format in the destination buffer. */
      *pDst++ = out1;
      /* store the imag result in 3.29 format in the destination buffer. */
      *pDst++ = out2;
  
      /* Decrement the blockSize loop counter */
      blkCnt--;
    }
  
  #else
  
    /* Run the below code for Cortex-M0 */
  
    /* loop Unrolling */
    blkCnt = numSamples >> 1u;
  
    /* First part of the processing with loop unrolling.  Compute 2 outputs at a time.     
     ** a second loop below computes the remaining 1 sample. */
    while(blkCnt > 0u)
    {
      /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
      /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
      a = *pSrcA++;
      b = *pSrcA++;
      c = *pSrcB++;
      d = *pSrcB++;
  
      mul1 = (q31_t) (((q63_t) a * c) >> 32);
      mul2 = (q31_t) (((q63_t) b * d) >> 32);
      mul3 = (q31_t) (((q63_t) a * d) >> 32);
      mul4 = (q31_t) (((q63_t) b * c) >> 32);
  
      mul1 = (mul1 >> 1);
      mul2 = (mul2 >> 1);
      mul3 = (mul3 >> 1);
      mul4 = (mul4 >> 1);
  
      out1 = mul1 - mul2;
      out2 = mul3 + mul4;
  
      /* store the real result in 3.29 format in the destination buffer. */
      *pDst++ = out1;
      /* store the imag result in 3.29 format in the destination buffer. */
      *pDst++ = out2;
  
      a = *pSrcA++;
      b = *pSrcA++;
      c = *pSrcB++;
      d = *pSrcB++;
  
      mul1 = (q31_t) (((q63_t) a * c) >> 32);
      mul2 = (q31_t) (((q63_t) b * d) >> 32);
      mul3 = (q31_t) (((q63_t) a * d) >> 32);
      mul4 = (q31_t) (((q63_t) b * c) >> 32);
  
      mul1 = (mul1 >> 1);
      mul2 = (mul2 >> 1);
      mul3 = (mul3 >> 1);
      mul4 = (mul4 >> 1);
  
      out1 = mul1 - mul2;
      out2 = mul3 + mul4;
  
      /* store the real result in 3.29 format in the destination buffer. */
      *pDst++ = out1;
      /* store the imag result in 3.29 format in the destination buffer. */
      *pDst++ = out2;
  
      /* Decrement the blockSize loop counter */
      blkCnt--;
    }
  
    /* If the blockSize is not a multiple of 2, compute any remaining output samples here.     
     ** No loop unrolling is used. */
    blkCnt = numSamples % 0x2u;
  
    while(blkCnt > 0u)
    {
      /* C[2 * i] = A[2 * i] * B[2 * i] - A[2 * i + 1] * B[2 * i + 1].  */
      /* C[2 * i + 1] = A[2 * i] * B[2 * i + 1] + A[2 * i + 1] * B[2 * i].  */
      a = *pSrcA++;
      b = *pSrcA++;
      c = *pSrcB++;
      d = *pSrcB++;
  
      mul1 = (q31_t) (((q63_t) a * c) >> 32);
      mul2 = (q31_t) (((q63_t) b * d) >> 32);
      mul3 = (q31_t) (((q63_t) a * d) >> 32);
      mul4 = (q31_t) (((q63_t) b * c) >> 32);
  
      mul1 = (mul1 >> 1);
      mul2 = (mul2 >> 1);
      mul3 = (mul3 >> 1);
      mul4 = (mul4 >> 1);
  
      out1 = mul1 - mul2;
      out2 = mul3 + mul4;
  
      /* store the real result in 3.29 format in the destination buffer. */
      *pDst++ = out1;
      /* store the imag result in 3.29 format in the destination buffer. */
      *pDst++ = out2;
  
      /* Decrement the blockSize loop counter */
      blkCnt--;
    }
  
  #endif /* #ifndef ARM_MATH_CM0 */
  
  }
  
  /**    
   * @} end of CmplxByCmplxMult group    
   */
  