text: /* ----------------------------------------------------------------------    
  * Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
  *    
  * $Date:        19. March 2015
  * $Revision: 	V.1.4.5
  *    
  * Project: 	    CMSIS DSP Library    
  * Title:	    arm_cmplx_mult_real_q15.c    
  *    
  * Description:	Q15 complex by real multiplication    
  *    
  * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
  *  
  * Redistribution and use in source and binary forms, with or without 
  * modification, are permitted provided that the following conditions
  * are met:
  *   - Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  *   - Redistributions in binary form must reproduce the above copyright
  *     notice, this list of conditions and the following disclaimer in
  *     the documentation and/or other materials provided with the 
  *     distribution.
  *   - Neither the name of ARM LIMITED nor the names of its contributors
  *     may be used to endorse or promote products derived from this
  *     software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 
  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  * POSSIBILITY OF SUCH DAMAGE. 
  * -------------------------------------------------------------------- */
  
  #include "arm_math.h"
  
  /**    
   * @ingroup groupCmplxMath    
   */
  
  /**    
   * @addtogroup CmplxByRealMult    
   * @{    
   */
  
  
  /**    
   * @brief  Q15 complex-by-real multiplication    
   * @param[in]  *pSrcCmplx points to the complex input vector    
   * @param[in]  *pSrcReal points to the real input vector    
   * @param[out]  *pCmplxDst points to the complex output vector    
   * @param[in]  numSamples number of samples in each vector    
   * @return none.    
   *    
   * <b>Scaling and Overflow Behavior:</b>    
   * \par    
   * The function uses saturating arithmetic.    
   * Results outside of the allowable Q15 range [0x8000 0x7FFF] will be saturated.    
   */
  
  void arm_cmplx_mult_real_q15(
    q15_t * pSrcCmplx,
    q15_t * pSrcReal,
    q15_t * pCmplxDst,
    uint32_t numSamples)
  {
    q15_t in;                                      /* Temporary variable to store input value */
  
  #ifndef ARM_MATH_CM0_FAMILY
  
    /* Run the below code for Cortex-M4 and Cortex-M3 */
    uint32_t blkCnt;                               /* loop counters */
    q31_t inA1, inA2;                              /* Temporary variables to hold input data */
    q31_t inB1;                                    /* Temporary variables to hold input data */
    q15_t out1, out2, out3, out4;                  /* Temporary variables to hold output data */
    q31_t mul1, mul2, mul3, mul4;                  /* Temporary variables to hold intermediate data */
  
    /* 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[i].            */
      /* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
      /* read complex number both real and imaginary from complex input buffer */
      inA1 = *__SIMD32(pSrcCmplx)++;
      /* read two real values at a time from real input buffer */
      inB1 = *__SIMD32(pSrcReal)++;
      /* read complex number both real and imaginary from complex input buffer */
      inA2 = *__SIMD32(pSrcCmplx)++;
  
      /* multiply complex number with real numbers */
  #ifndef ARM_MATH_BIG_ENDIAN
  
      mul1 = (q31_t) ((q15_t) (inA1) * (q15_t) (inB1));
      mul2 = (q31_t) ((q15_t) (inA1 >> 16) * (q15_t) (inB1));
      mul3 = (q31_t) ((q15_t) (inA2) * (q15_t) (inB1 >> 16));
      mul4 = (q31_t) ((q15_t) (inA2 >> 16) * (q15_t) (inB1 >> 16));
  
  #else
  
      mul2 = (q31_t) ((q15_t) (inA1 >> 16) * (q15_t) (inB1 >> 16));
      mul1 = (q31_t) ((q15_t) inA1 * (q15_t) (inB1 >> 16));
      mul4 = (q31_t) ((q15_t) (inA2 >> 16) * (q15_t) inB1);
      mul3 = (q31_t) ((q15_t) inA2 * (q15_t) inB1);
  
  #endif //      #ifndef ARM_MATH_BIG_ENDIAN
  
      /* saturate the result */
      out1 = (q15_t) __SSAT(mul1 >> 15u, 16);
      out2 = (q15_t) __SSAT(mul2 >> 15u, 16);
      out3 = (q15_t) __SSAT(mul3 >> 15u, 16);
      out4 = (q15_t) __SSAT(mul4 >> 15u, 16);
  
      /* pack real and imaginary outputs and store them to destination */
      *__SIMD32(pCmplxDst)++ = __PKHBT(out1, out2, 16);
      *__SIMD32(pCmplxDst)++ = __PKHBT(out3, out4, 16);
  
      inA1 = *__SIMD32(pSrcCmplx)++;
      inB1 = *__SIMD32(pSrcReal)++;
      inA2 = *__SIMD32(pSrcCmplx)++;
  
  #ifndef ARM_MATH_BIG_ENDIAN
  
      mul1 = (q31_t) ((q15_t) (inA1) * (q15_t) (inB1));
      mul2 = (q31_t) ((q15_t) (inA1 >> 16) * (q15_t) (inB1));
      mul3 = (q31_t) ((q15_t) (inA2) * (q15_t) (inB1 >> 16));
      mul4 = (q31_t) ((q15_t) (inA2 >> 16) * (q15_t) (inB1 >> 16));
  
  #else
  
      mul2 = (q31_t) ((q15_t) (inA1 >> 16) * (q15_t) (inB1 >> 16));
      mul1 = (q31_t) ((q15_t) inA1 * (q15_t) (inB1 >> 16));
      mul4 = (q31_t) ((q15_t) (inA2 >> 16) * (q15_t) inB1);
      mul3 = (q31_t) ((q15_t) inA2 * (q15_t) inB1);
  
  #endif //      #ifndef ARM_MATH_BIG_ENDIAN
  
      out1 = (q15_t) __SSAT(mul1 >> 15u, 16);
      out2 = (q15_t) __SSAT(mul2 >> 15u, 16);
      out3 = (q15_t) __SSAT(mul3 >> 15u, 16);
      out4 = (q15_t) __SSAT(mul4 >> 15u, 16);
  
      *__SIMD32(pCmplxDst)++ = __PKHBT(out1, out2, 16);
      *__SIMD32(pCmplxDst)++ = __PKHBT(out3, out4, 16);
  
      /* Decrement the numSamples loop counter */
      blkCnt--;
    }
  
    /* If the numSamples 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[i].            */
      /* C[2 * i + 1] = A[2 * i + 1] * B[i].        */
      in = *pSrcReal++;
      /* store the result in the destination buffer. */
      *pCmplxDst++ =
        (q15_t) __SSAT((((q31_t) (*pSrcCmplx++) * (in)) >> 15), 16);
      *pCmplxDst++ =
        (q15_t) __SSAT((((q31_t) (*pSrcCmplx++) * (in)) >> 15), 16);
  
      /* Decrement the numSamples loop counter */
      blkCnt--;
    }
  
  #else
  
    /* Run the below code for Cortex-M0 */
  
    while(numSamples > 0u)
    {
      /* realOut = realA * realB.            */
      /* imagOut = imagA * realB.                */
      in = *pSrcReal++;
      /* store the result in the destination buffer. */
      *pCmplxDst++ =
        (q15_t) __SSAT((((q31_t) (*pSrcCmplx++) * (in)) >> 15), 16);
      *pCmplxDst++ =
        (q15_t) __SSAT((((q31_t) (*pSrcCmplx++) * (in)) >> 15), 16);
  
      /* Decrement the numSamples loop counter */
      numSamples--;
    }
  
  #endif /* #ifndef ARM_MATH_CM0_FAMILY */
  
  }
  
  /**    
   * @} end of CmplxByRealMult group    
   */
  