/* ----------------------------------------------------------------------
* 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_conj_q31.c
*
* Description:  Q31 complex conjugate.
*
* 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
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* ---------------------------------------------------------------------------- */
#include "arm_math.h"

/**
 * @ingroup groupCmplxMath
 */

/**
 * @addtogroup cmplx_conj
 * @{
 */

/**
 * @brief  Q31 complex conjugate.
 * @param  *pSrc points to the input vector
 * @param  *pDst points to the output vector
 * @param  numSamples number of complex samples in each vector
 * @return none.
 *
 * <b>Scaling and Overflow Behavior:</b>
 * \par
 * The function uses saturating arithmetic.
 * The Q31 value -1 (0x80000000) will be saturated to the maximum allowable positive value 0x7FFFFFFF.
 */

void arm_cmplx_conj_q31(
    q31_t * pSrc,
    q31_t * pDst,
    uint32_t numSamples)
{
    uint32_t blkCnt;                               /* loop counter */
    q31_t in;                                      /* Input value */

#ifndef ARM_MATH_CM0_FAMILY

    /* Run the below code for Cortex-M4 and Cortex-M3 */
    q31_t inR1, inR2, inR3, inR4;                  /* Temporary real variables */
    q31_t inI1, inI2, inI3, inI4;                  /* Temporary imaginary variables */

    /*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[0]+jC[1] = A[0]+ j (-1) A[1] */
        /* Calculate Complex Conjugate and then store the results in the destination buffer. */
        /* Saturated to 0x7fffffff if the input is -1(0x80000000) */
        /* read real input sample */
        inR1 = pSrc[0];
        /* store real input sample */
        pDst[0] = inR1;

        /* read imaginary input sample */
        inI1 = pSrc[1];

        /* read real input sample */
        inR2 = pSrc[2];
        /* store real input sample */
        pDst[2] = inR2;

        /* read imaginary input sample */
        inI2 = pSrc[3];

        /* negate imaginary input sample */
        inI1 = __QSUB(0, inI1);

        /* read real input sample */
        inR3 = pSrc[4];
        /* store real input sample */
        pDst[4] = inR3;

        /* read imaginary input sample */
        inI3 = pSrc[5];

        /* negate imaginary input sample */
        inI2 = __QSUB(0, inI2);

        /* read real input sample */
        inR4 = pSrc[6];
        /* store real input sample */
        pDst[6] = inR4;

        /* negate imaginary input sample */
        inI3 = __QSUB(0, inI3);

        /* store imaginary input sample */
        inI4 = pSrc[7];

        /* store imaginary input samples */
        pDst[1] = inI1;

        /* negate imaginary input sample */
        inI4 = __QSUB(0, inI4);

        /* store imaginary input samples */
        pDst[3] = inI2;

        /* increment source pointer by 8 to proecess next samples */
        pSrc += 8u;

        /* store imaginary input samples */
        pDst[5] = inI3;
        pDst[7] = inI4;

        /* increment destination pointer by 8 to process next samples */
        pDst += 8u;

        /* 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 % 0x4u;

#else

    /* Run the below code for Cortex-M0 */
    blkCnt = numSamples;


#endif /* #ifndef ARM_MATH_CM0_FAMILY */

    while(blkCnt > 0u)
    {
        /* C[0]+jC[1] = A[0]+ j (-1) A[1] */
        /* Calculate Complex Conjugate and then store the results in the destination buffer. */
        /* Saturated to 0x7fffffff if the input is -1(0x80000000) */
        *pDst++ = *pSrc++;
        in = *pSrc++;
        *pDst++ = (in == INT32_MIN) ? INT32_MAX : -in;

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

/**
 * @} end of cmplx_conj group
 */
