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/* ----------------------------------------------------------------------    
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* Copyright (C) 2010-2014 ARM Limited. All rights reserved.    
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*    
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* $Date:        19. March 2015
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* $Revision:    V.1.4.5  
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*    
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* Project:          CMSIS DSP Library    
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* Title:                arm_max_q31.c    
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*    
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* Description:  Maximum value of a Q31 vector.    
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*    
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* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0
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*  
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*   - Redistributions of source code must retain the above copyright
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*     notice, this list of conditions and the following disclaimer.
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*   - Redistributions in binary form must reproduce the above copyright
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*     notice, this list of conditions and the following disclaimer in
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*     the documentation and/or other materials provided with the
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*     distribution.
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*   - Neither the name of ARM LIMITED nor the names of its contributors
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*     may be used to endorse or promote products derived from this
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*     software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
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* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.  
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* ---------------------------------------------------------------------------- */
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#include "arm_math.h"
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/**    
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 * @ingroup groupStats    
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 */
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/**    
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 * @addtogroup Max    
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 * @{    
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 */
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/**    
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 * @brief Maximum value of a Q31 vector.    
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 * @param[in]       *pSrc points to the input vector    
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 * @param[in]       blockSize length of the input vector    
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 * @param[out]      *pResult maximum value returned here    
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 * @param[out]      *pIndex index of maximum value returned here    
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 * @return none.    
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 */
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void arm_max_q31(
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  q31_t * pSrc,
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  uint32_t blockSize,
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  q31_t * pResult,
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  uint32_t * pIndex)
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{
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#ifndef ARM_MATH_CM0_FAMILY
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  /* Run the below code for Cortex-M4 and Cortex-M3 */
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  q31_t maxVal1, maxVal2, out;                   /* Temporary variables to store the output value. */
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  uint32_t blkCnt, outIndex, count;              /* loop counter */
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  /* Initialise the count value. */
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  count = 0u;
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  /* Initialise the index value to zero. */
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  outIndex = 0u;
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  /* Load first input value that act as reference value for comparision */
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  out = *pSrc++;
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  /* Loop unrolling */
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  blkCnt = (blockSize - 1u) >> 2u;
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  /* Run the below code for Cortex-M4 and Cortex-M3 */
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  while(blkCnt > 0u)
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  {
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    /* Initialize maxVal to the next consecutive values one by one */
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    maxVal1 = *pSrc++;
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    maxVal2 = *pSrc++;
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    /* compare for the maximum value */
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    if(out < maxVal1)
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    {
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      /* Update the maximum value and its index */
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      out = maxVal1;
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      outIndex = count + 1u;
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    }
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    maxVal1 = *pSrc++;
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    /* compare for the maximum value */
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    if(out < maxVal2)
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    {
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      /* Update the maximum value and its index */
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      out = maxVal2;
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      outIndex = count + 2u;
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    }
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    maxVal2 = *pSrc++;
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    /* compare for the maximum value */
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    if(out < maxVal1)
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    {
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      /* Update the maximum value and its index */
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      out = maxVal1;
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      outIndex = count + 3u;
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    }
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    /* compare for the maximum value */
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    if(out < maxVal2)
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    {
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      /* Update the maximum value and its index */
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      out = maxVal2;
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      outIndex = count + 4u;
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    }
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    count += 4u;
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    /* Decrement the loop counter */
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    blkCnt--;
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  }
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  /* if (blockSize - 1u) is not multiple of 4 */
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  blkCnt = (blockSize - 1u) % 4u;
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#else
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  /* Run the below code for Cortex-M0 */
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  q31_t maxVal1, out;                            /* Temporary variables to store the output value. */
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  uint32_t blkCnt, outIndex;                     /* loop counter */
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  /* Initialise the index value to zero. */
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  outIndex = 0u;
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  /* Load first input value that act as reference value for comparision */
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  out = *pSrc++;
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  blkCnt = (blockSize - 1u);
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#endif /* #ifndef ARM_MATH_CM0_FAMILY */
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  while(blkCnt > 0u)
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  {
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    /* Initialize maxVal to the next consecutive values one by one */
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    maxVal1 = *pSrc++;
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    /* compare for the maximum value */
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    if(out < maxVal1)
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    {
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      /* Update the maximum value and it's index */
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      out = maxVal1;
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      outIndex = blockSize - blkCnt;
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    }
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    /* Decrement the loop counter */
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    blkCnt--;
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  }
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  /* Store the maximum value and its index into destination pointers */
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  *pResult = out;
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  *pIndex = outIndex;
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}
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/**    
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 * @} end of Max group    
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 */