/* ----------------------------------------------------------------------
* 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_mult_real_q31.c
*
* Description:  Q31 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,
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* -------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @addtogroup CmplxByRealMult
 * @{
 */


/**
 * @brief  Q31 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 Q31 range[0x80000000 0x7FFFFFFF] will be saturated.
 */

void arm_cmplx_mult_real_q31(
    q31_t * pSrcCmplx,
    q31_t * pSrcReal,
    q31_t * pCmplxDst,
    uint32_t numSamples)
{
    q31_t inA1;                                    /* 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 inA2, inA3, inA4;                        /* Temporary variables to hold input data */
    q31_t inB1, inB2;                              /* Temporary variabels to hold input data */
    q31_t out1, out2, out3, out4;                  /* Temporary variables to hold output 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 real input from complex input buffer */
        inA1 = *pSrcCmplx++;
        inA2 = *pSrcCmplx++;
        /* read input from real input bufer */
        inB1 = *pSrcReal++;
        inB2 = *pSrcReal++;
        /* read imaginary input from complex input buffer */
        inA3 = *pSrcCmplx++;
        inA4 = *pSrcCmplx++;

        /* multiply complex input with real input */
        out1 = ((q63_t) inA1 * inB1) >> 32;
        out2 = ((q63_t) inA2 * inB1) >> 32;
        out3 = ((q63_t) inA3 * inB2) >> 32;
        out4 = ((q63_t) inA4 * inB2) >> 32;

        /* sature the result */
        out1 = __SSAT(out1, 31);
        out2 = __SSAT(out2, 31);
        out3 = __SSAT(out3, 31);
        out4 = __SSAT(out4, 31);

        /* get result in 1.31 format */
        out1 = out1 << 1;
        out2 = out2 << 1;
        out3 = out3 << 1;
        out4 = out4 << 1;

        /* store the result to destination buffer */
        *pCmplxDst++ = out1;
        *pCmplxDst++ = out2;
        *pCmplxDst++ = out3;
        *pCmplxDst++ = out4;

        /* read real input from complex input buffer */
        inA1 = *pSrcCmplx++;
        inA2 = *pSrcCmplx++;
        /* read input from real input bufer */
        inB1 = *pSrcReal++;
        inB2 = *pSrcReal++;
        /* read imaginary input from complex input buffer */
        inA3 = *pSrcCmplx++;
        inA4 = *pSrcCmplx++;

        /* multiply complex input with real input */
        out1 = ((q63_t) inA1 * inB1) >> 32;
        out2 = ((q63_t) inA2 * inB1) >> 32;
        out3 = ((q63_t) inA3 * inB2) >> 32;
        out4 = ((q63_t) inA4 * inB2) >> 32;

        /* sature the result */
        out1 = __SSAT(out1, 31);
        out2 = __SSAT(out2, 31);
        out3 = __SSAT(out3, 31);
        out4 = __SSAT(out4, 31);

        /* get result in 1.31 format */
        out1 = out1 << 1;
        out2 = out2 << 1;
        out3 = out3 << 1;
        out4 = out4 << 1;

        /* store the result to destination buffer */
        *pCmplxDst++ = out1;
        *pCmplxDst++ = out2;
        *pCmplxDst++ = out3;
        *pCmplxDst++ = out4;

        /* 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].        */
        /* read real input from complex input buffer */
        inA1 = *pSrcCmplx++;
        inA2 = *pSrcCmplx++;
        /* read input from real input bufer */
        inB1 = *pSrcReal++;

        /* multiply complex input with real input */
        out1 = ((q63_t) inA1 * inB1) >> 32;
        out2 = ((q63_t) inA2 * inB1) >> 32;

        /* sature the result */
        out1 = __SSAT(out1, 31);
        out2 = __SSAT(out2, 31);

        /* get result in 1.31 format */
        out1 = out1 << 1;
        out2 = out2 << 1;

        /* store the result to destination buffer */
        *pCmplxDst++ = out1;
        *pCmplxDst++ = out2;

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

#else

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

    while(numSamples > 0u)
    {
        /* realOut = realA * realB.            */
        /* imagReal = imagA * realB.               */
        inA1 = *pSrcReal++;
        /* store the result in the destination buffer. */
        *pCmplxDst++ =
            (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);
        *pCmplxDst++ =
            (q31_t) clip_q63_to_q31(((q63_t) * pSrcCmplx++ * inA1) >> 31);

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

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

}

/**
 * @} end of CmplxByRealMult group
 */
