170 lines
4.5 KiB
C
170 lines
4.5 KiB
C
/* ----------------------------------------------------------------------
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* Project: CMSIS DSP Library
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* Title: arm_max_f32.c
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* Description: Maximum value of a floating-point vector
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*
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* $Date: 27. January 2017
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* $Revision: V.1.5.1
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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) 2010-2017 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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/**
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* @ingroup groupStats
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*/
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/**
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* @defgroup Max Maximum
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*
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* Computes the maximum value of an array of data.
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* The function returns both the maximum 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 Max
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* @{
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*/
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/**
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* @brief Maximum 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 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_f32(
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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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#if defined (ARM_MATH_DSP)
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/* Run the below code for Cortex-M4 and Cortex-M3 */
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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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/* 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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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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/* 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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/* 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 + 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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float32_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 /* #if defined (ARM_MATH_DSP) */
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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 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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/**
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* @} end of Max group
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*/
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