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/* ----------------------------------------------------------------------    

* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    

*    

* $Date:        19. October 2015

* $Revision:    V.1.4.5 a

*    

* 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    

 */