269 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			269 lines
		
	
	
		
			6.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/* ----------------------------------------------------------------------
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 * Project:      CMSIS DSP Library
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 * Title:        arm_min_f32.c
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 * Description:  Minimum value of a floating-point vector
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 *
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 * $Date:        18. March 2019
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 * $Revision:    V1.6.0
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 *
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 * Target Processor: Cortex-M cores
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 * -------------------------------------------------------------------- */
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/*
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 * Copyright (C) 2010-2019 ARM Limited or its affiliates. All rights reserved.
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 *
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 * SPDX-License-Identifier: Apache-2.0
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 *
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 * Licensed under the Apache License, Version 2.0 (the License); you may
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 * not use this file except in compliance with the License.
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 * You may obtain a copy of the License at
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 *
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 * www.apache.org/licenses/LICENSE-2.0
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 *
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 * Unless required by applicable law or agreed to in writing, software
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 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
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 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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 * See the License for the specific language governing permissions and
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 * limitations under the License.
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 */
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#include "arm_math.h"
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#include <limits.h>
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/**
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  @ingroup groupStats
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 */
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/**
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  @defgroup Min Minimum
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  Computes the minimum value of an array of data.
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  The function returns both the minimum value and its position within the array.
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  There are separate functions for floating-point, Q31, Q15, and Q7 data types.
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 */
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/**
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  @addtogroup Min
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  @{
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 */
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/**
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  @brief         Minimum value of a floating-point vector.
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  @param[in]     pSrc       points to the input vector
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  @param[in]     blockSize  number of samples in input vector
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  @param[out]    pResult    minimum value returned here
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  @param[out]    pIndex     index of minimum value returned here
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  @return        none
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 */
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#if defined(ARM_MATH_NEON)
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void arm_min_f32(
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  const float32_t * pSrc,
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  uint32_t blockSize,
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  float32_t * pResult,
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  uint32_t * pIndex)
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{
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  float32_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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  float32x4_t outV, srcV;
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  float32x2_t outV2;
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  uint32x4_t idxV;
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  uint32x4_t maxIdx={ULONG_MAX,ULONG_MAX,ULONG_MAX,ULONG_MAX};
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  uint32x4_t index={4,5,6,7};
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  uint32x4_t delta={4,4,4,4};
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  uint32x4_t countV={0,1,2,3};
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  uint32x2_t countV2;
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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 comparison */
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  if (blockSize <= 3)
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  {
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      out = *pSrc++;
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      blkCnt = blockSize - 1;
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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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  }
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  else
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  {
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      outV = vld1q_f32(pSrc);
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      pSrc += 4;
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      /* Compute 4 outputs at a time */
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      blkCnt = (blockSize - 4 ) >> 2U;
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      while (blkCnt > 0U)
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      {
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        srcV = vld1q_f32(pSrc);
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        pSrc += 4;
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        idxV = vcltq_f32(srcV, outV);
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        outV = vbslq_f32(idxV, srcV, outV );
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        countV = vbslq_u32(idxV, index,countV );
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        index = vaddq_u32(index,delta);
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        /* Decrement the loop counter */
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        blkCnt--;
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      }
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      outV2 = vpmin_f32(vget_low_f32(outV),vget_high_f32(outV));
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      outV2 = vpmin_f32(outV2,outV2);
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      out = outV2[0];
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      idxV = vceqq_f32(outV, vdupq_n_f32(out));
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      countV = vbslq_u32(idxV, countV,maxIdx);
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      countV2 = vpmin_u32(vget_low_u32(countV),vget_high_u32(countV));
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      countV2 = vpmin_u32(countV2,countV2);
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      outIndex = countV2[0];
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      /* if (blockSize - 1U) is not multiple of 4 */
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      blkCnt = (blockSize - 4 ) % 4U;
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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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  }
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  /* Store the maximum value and it's index into destination pointers */
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  *pResult = out;
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  *pIndex = outIndex;
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}
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#else
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void arm_min_f32(
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  const float32_t * pSrc,
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        uint32_t blockSize,
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        float32_t * pResult,
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        uint32_t * pIndex)
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{
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        float32_t minVal, out;                         /* Temporary variables to store the output value. */
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        uint32_t blkCnt, outIndex;                     /* Loop counter */
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#if defined (ARM_MATH_LOOPUNROLL)
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        uint32_t index;                                /* index of maximum value */
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#endif
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  /* Initialise 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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#if defined (ARM_MATH_LOOPUNROLL)
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  /* Initialise index of maximum value. */
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  index = 0U;
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  /* Loop unrolling: Compute 4 outputs at a time */
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  blkCnt = (blockSize - 1U) >> 2U;
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  while (blkCnt > 0U)
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  {
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    /* Initialize minVal to next consecutive values one by one */
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    minVal = *pSrc++;
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    /* compare for the minimum value */
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    if (out > minVal)
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    {
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      /* Update the minimum value and it's index */
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      out = minVal;
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      outIndex = index + 1U;
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    }
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    minVal = *pSrc++;
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    if (out > minVal)
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    {
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      out = minVal;
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      outIndex = index + 2U;
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    }
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    minVal = *pSrc++;
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    if (out > minVal)
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    {
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      out = minVal;
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      outIndex = index + 3U;
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    }
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    minVal = *pSrc++;
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    if (out > minVal)
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    {
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      out = minVal;
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      outIndex = index + 4U;
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    }
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    index += 4U;
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    /* Decrement loop counter */
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    blkCnt--;
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  }
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  /* Loop unrolling: Compute remaining outputs */
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  blkCnt = (blockSize - 1U) % 4U;
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#else
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  /* Initialize blkCnt with number of samples */
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  blkCnt = (blockSize - 1U);
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#endif /* #if defined (ARM_MATH_LOOPUNROLL) */
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  while (blkCnt > 0U)
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  {
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    /* Initialize minVal to the next consecutive values one by one */
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    minVal = *pSrc++;
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    /* compare for the minimum value */
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    if (out > minVal)
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    {
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      /* Update the minimum value and it's index */
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      out = minVal;
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      outIndex = blockSize - blkCnt;
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    }
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    /* Decrement loop counter */
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    blkCnt--;
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  }
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  /* Store the minimum value and it's index into destination pointers */
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  *pResult = out;
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  *pIndex = outIndex;
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}
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#endif /* #if defined(ARM_MATH_NEON) */
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/**
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  @} end of Min group
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 */
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