/* ----------------------------------------------------------------------
* 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_max_q7.c
*
* Description:  Maximum value of a Q7 vector.
*
* 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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* POSSIBILITY OF SUCH DAMAGE.
* ---------------------------------------------------------------------------- */

#include "arm_math.h"

/**
 * @ingroup groupStats
 */

/**
 * @addtogroup Max
 * @{
 */


/**
 * @brief Maximum value of a Q7 vector.
 * @param[in]       *pSrc points to the input vector
 * @param[in]       blockSize length of the input vector
 * @param[out]      *pResult maximum value returned here
 * @param[out]      *pIndex index of maximum value returned here
  * @return none.
 */

void arm_max_q7(
    q7_t * pSrc,
    uint32_t blockSize,
    q7_t * pResult,
    uint32_t * pIndex)
{
#ifndef ARM_MATH_CM0_FAMILY
    /* Run the below code for Cortex-M4 and Cortex-M3 */

    q7_t maxVal1, maxVal2, out;                    /* Temporary variables to store the output value. */
    uint32_t blkCnt, outIndex, count;              /* loop counter */

    /* Initialise the count value. */
    count = 0u;
    /* Initialise the index value to zero. */
    outIndex = 0u;
    /* Load first input value that act as reference value for comparision */
    out = *pSrc++;

    /* Loop unrolling */
    blkCnt = (blockSize - 1u) >> 2u;

    /* Run the below code for Cortex-M4 and Cortex-M3 */
    while(blkCnt > 0u)
    {
        /* Initialize maxVal to the next consecutive values one by one */
        maxVal1 = *pSrc++;

        maxVal2 = *pSrc++;

        /* compare for the maximum value */
        if(out < maxVal1)
        {
            /* Update the maximum value and its index */
            out = maxVal1;
            outIndex = count + 1u;
        }

        maxVal1 = *pSrc++;

        /* compare for the maximum value */
        if(out < maxVal2)
        {
            /* Update the maximum value and its index */
            out = maxVal2;
            outIndex = count + 2u;
        }

        maxVal2 = *pSrc++;

        /* compare for the maximum value */
        if(out < maxVal1)
        {
            /* Update the maximum value and its index */
            out = maxVal1;
            outIndex = count + 3u;
        }

        /* compare for the maximum value */
        if(out < maxVal2)
        {
            /* Update the maximum value and its index */
            out = maxVal2;
            outIndex = count + 4u;
        }

        count += 4u;

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

    /* if (blockSize - 1u) is not multiple of 4 */
    blkCnt = (blockSize - 1u) % 4u;

#else

    /* Run the below code for Cortex-M0 */
    q7_t maxVal1, out;                             /* Temporary variables to store the output value. */
    uint32_t blkCnt, outIndex;                     /* loop counter */

    /* Initialise the index value to zero. */
    outIndex = 0u;
    /* Load first input value that act as reference value for comparision */
    out = *pSrc++;

    blkCnt = (blockSize - 1u);

#endif /* #ifndef ARM_MATH_CM0_FAMILY */

    while(blkCnt > 0u)
    {
        /* Initialize maxVal to the next consecutive values one by one */
        maxVal1 = *pSrc++;

        /* compare for the maximum value */
        if(out < maxVal1)
        {
            /* Update the maximum value and it's index */
            out = maxVal1;
            outIndex = blockSize - blkCnt;
        }
        /* Decrement the loop counter */
        blkCnt--;

    }

    /* Store the maximum value and its index into destination pointers */
    *pResult = out;
    *pIndex = outIndex;

}

/**
 * @} end of Max group
 */
