demo of driving MAX2719 dot matrix displays with STM32F103 Bluepill
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f103-dotmatrix/lib/cmsis/DSP_Lib/Source/StatisticsFunctions/arm_max_q7.c

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/* ----------------------------------------------------------------------
* Copyright (C) 2010-2014 ARM Limited. All rights reserved.
*
* $Date: 12. March 2014
* $Revision: V1.4.4
*
* 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,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
* CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* 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
*/