/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date: 16/10/14 6:01p $Revision:  V.1.4.5
*
* Project:      CMSIS DSP Library
* Title:        arm_cmplx_dot_prod_f32.c
*
* Description:  Floating-point complex dot product
*
* 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
 */

/**
 * @defgroup cmplx_dot_prod Complex Dot Product
 *
 * Computes the dot product of two complex vectors.
 * The vectors are multiplied element-by-element and then summed.
 *
 * The <code>pSrcA</code> points to the first complex input vector and
 * <code>pSrcB</code> points to the second complex input vector.
 * <code>numSamples</code> specifies the number of complex samples
 * and the data in each array is stored in an interleaved fashion
 * (real, imag, real, imag, ...).
 * Each array has a total of <code>2*numSamples</code> values.
 *
 * The underlying algorithm is used:
 * <pre>
 * realResult=0;
 * imagResult=0;
 * for(n=0; n<numSamples; n++) {
 *     realResult += pSrcA[(2*n)+0]*pSrcB[(2*n)+0] - pSrcA[(2*n)+1]*pSrcB[(2*n)+1];
 *     imagResult += pSrcA[(2*n)+0]*pSrcB[(2*n)+1] + pSrcA[(2*n)+1]*pSrcB[(2*n)+0];
 * }
 * </pre>
 *
 * There are separate functions for floating-point, Q15, and Q31 data types.
 */

/**
 * @addtogroup cmplx_dot_prod
 * @{
 */

/**
 * @brief  Floating-point complex dot product
 * @param  *pSrcA points to the first input vector
 * @param  *pSrcB points to the second input vector
 * @param  numSamples number of complex samples in each vector
 * @param  *realResult real part of the result returned here
 * @param  *imagResult imaginary part of the result returned here
 * @return none.
 */

void arm_cmplx_dot_prod_f32(
    float32_t * pSrcA,
    float32_t * pSrcB,
    uint32_t numSamples,
    float32_t * realResult,
    float32_t * imagResult)
{
    float32_t real_sum = 0.0f, imag_sum = 0.0f;    /* Temporary result storage */
    float32_t a0, b0, c0, d0;

#ifndef ARM_MATH_CM0_FAMILY

    /* Run the below code for Cortex-M4 and Cortex-M3 */
    uint32_t blkCnt;                               /* loop counter */

    /*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)
    {
        a0 = *pSrcA++;
        b0 = *pSrcA++;
        c0 = *pSrcB++;
        d0 = *pSrcB++;

        real_sum += a0 * c0;
        imag_sum += a0 * d0;
        real_sum -= b0 * d0;
        imag_sum += b0 * c0;

        a0 = *pSrcA++;
        b0 = *pSrcA++;
        c0 = *pSrcB++;
        d0 = *pSrcB++;

        real_sum += a0 * c0;
        imag_sum += a0 * d0;
        real_sum -= b0 * d0;
        imag_sum += b0 * c0;

        a0 = *pSrcA++;
        b0 = *pSrcA++;
        c0 = *pSrcB++;
        d0 = *pSrcB++;

        real_sum += a0 * c0;
        imag_sum += a0 * d0;
        real_sum -= b0 * d0;
        imag_sum += b0 * c0;

        a0 = *pSrcA++;
        b0 = *pSrcA++;
        c0 = *pSrcB++;
        d0 = *pSrcB++;

        real_sum += a0 * c0;
        imag_sum += a0 * d0;
        real_sum -= b0 * d0;
        imag_sum += b0 * c0;

        /* Decrement the 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 & 0x3u;

    while(blkCnt > 0u)
    {
        a0 = *pSrcA++;
        b0 = *pSrcA++;
        c0 = *pSrcB++;
        d0 = *pSrcB++;

        real_sum += a0 * c0;
        imag_sum += a0 * d0;
        real_sum -= b0 * d0;
        imag_sum += b0 * c0;

        /* Decrement the loop counter */
        blkCnt--;
    }

#else

    /* Run the below code for Cortex-M0 */

    while(numSamples > 0u)
    {
        a0 = *pSrcA++;
        b0 = *pSrcA++;
        c0 = *pSrcB++;
        d0 = *pSrcB++;

        real_sum += a0 * c0;
        imag_sum += a0 * d0;
        real_sum -= b0 * d0;
        imag_sum += b0 * c0;

        /* Decrement the loop counter */
        numSamples--;
    }

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

    /* Store the real and imaginary results in the destination buffers */
    *realResult = real_sum;
    *imagResult = imag_sum;
}

/**
 * @} end of cmplx_dot_prod group
 */
