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| bfc108 | 1 | /* ---------------------------------------------------------------------- |
| Q | 2 | * Copyright (C) 2010-2014 ARM Limited. All rights reserved. |
| 3 | * | |
| 4 | * $Date: 19. March 2015 | |
| 5 | * $Revision: V.1.4.5 | |
| 6 | * | |
| 7 | * Project: CMSIS DSP Library | |
| 8 | * Title: arm_max_f32.c | |
| 9 | * | |
| 10 | * Description: Maximum value of a floating-point vector. | |
| 11 | * | |
| 12 | * Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | |
| 13 | * | |
| 14 | * Redistribution and use in source and binary forms, with or without | |
| 15 | * modification, are permitted provided that the following conditions | |
| 16 | * are met: | |
| 17 | * - Redistributions of source code must retain the above copyright | |
| 18 | * notice, this list of conditions and the following disclaimer. | |
| 19 | * - Redistributions in binary form must reproduce the above copyright | |
| 20 | * notice, this list of conditions and the following disclaimer in | |
| 21 | * the documentation and/or other materials provided with the | |
| 22 | * distribution. | |
| 23 | * - Neither the name of ARM LIMITED nor the names of its contributors | |
| 24 | * may be used to endorse or promote products derived from this | |
| 25 | * software without specific prior written permission. | |
| 26 | * | |
| 27 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |
| 28 | * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |
| 29 | * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |
| 30 | * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |
| 31 | * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, | |
| 32 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, | |
| 33 | * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
| 34 | * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER | |
| 35 | * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 36 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN | |
| 37 | * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE | |
| 38 | * POSSIBILITY OF SUCH DAMAGE. | |
| 39 | * ---------------------------------------------------------------------------- */ | |
| 40 | ||
| 41 | #include "arm_math.h" | |
| 42 | ||
| 43 | /** | |
| 44 | * @ingroup groupStats | |
| 45 | */ | |
| 46 | ||
| 47 | /** | |
| 48 | * @defgroup Max Maximum | |
| 49 | * | |
| 50 | * Computes the maximum value of an array of data. | |
| 51 | * The function returns both the maximum value and its position within the array. | |
| 52 | * There are separate functions for floating-point, Q31, Q15, and Q7 data types. | |
| 53 | */ | |
| 54 | ||
| 55 | /** | |
| 56 | * @addtogroup Max | |
| 57 | * @{ | |
| 58 | */ | |
| 59 | ||
| 60 | ||
| 61 | /** | |
| 62 | * @brief Maximum value of a floating-point vector. | |
| 63 | * @param[in] *pSrc points to the input vector | |
| 64 | * @param[in] blockSize length of the input vector | |
| 65 | * @param[out] *pResult maximum value returned here | |
| 66 | * @param[out] *pIndex index of maximum value returned here | |
| 67 | * @return none. | |
| 68 | */ | |
| 69 | ||
| 70 | void arm_max_f32( | |
| 71 | float32_t * pSrc, | |
| 72 | uint32_t blockSize, | |
| 73 | float32_t * pResult, | |
| 74 | uint32_t * pIndex) | |
| 75 | { | |
| 76 | #ifndef ARM_MATH_CM0_FAMILY | |
| 77 | ||
| 78 | /* Run the below code for Cortex-M4 and Cortex-M3 */ | |
| 79 | float32_t maxVal1, maxVal2, out; /* Temporary variables to store the output value. */ | |
| 80 | uint32_t blkCnt, outIndex, count; /* loop counter */ | |
| 81 | ||
| 82 | /* Initialise the count value. */ | |
| 83 | count = 0u; | |
| 84 | /* Initialise the index value to zero. */ | |
| 85 | outIndex = 0u; | |
| 86 | /* Load first input value that act as reference value for comparision */ | |
| 87 | out = *pSrc++; | |
| 88 | ||
| 89 | /* Loop unrolling */ | |
| 90 | blkCnt = (blockSize - 1u) >> 2u; | |
| 91 | ||
| 92 | /* Run the below code for Cortex-M4 and Cortex-M3 */ | |
| 93 | while(blkCnt > 0u) | |
| 94 | { | |
| 95 | /* Initialize maxVal to the next consecutive values one by one */ | |
| 96 | maxVal1 = *pSrc++; | |
| 97 | ||
| 98 | maxVal2 = *pSrc++; | |
| 99 | ||
| 100 | /* compare for the maximum value */ | |
| 101 | if(out < maxVal1) | |
| 102 | { | |
| 103 | /* Update the maximum value and its index */ | |
| 104 | out = maxVal1; | |
| 105 | outIndex = count + 1u; | |
| 106 | } | |
| 107 | ||
| 108 | maxVal1 = *pSrc++; | |
| 109 | ||
| 110 | /* compare for the maximum value */ | |
| 111 | if(out < maxVal2) | |
| 112 | { | |
| 113 | /* Update the maximum value and its index */ | |
| 114 | out = maxVal2; | |
| 115 | outIndex = count + 2u; | |
| 116 | } | |
| 117 | ||
| 118 | maxVal2 = *pSrc++; | |
| 119 | ||
| 120 | /* compare for the maximum value */ | |
| 121 | if(out < maxVal1) | |
| 122 | { | |
| 123 | /* Update the maximum value and its index */ | |
| 124 | out = maxVal1; | |
| 125 | outIndex = count + 3u; | |
| 126 | } | |
| 127 | ||
| 128 | /* compare for the maximum value */ | |
| 129 | if(out < maxVal2) | |
| 130 | { | |
| 131 | /* Update the maximum value and its index */ | |
| 132 | out = maxVal2; | |
| 133 | outIndex = count + 4u; | |
| 134 | } | |
| 135 | ||
| 136 | count += 4u; | |
| 137 | ||
| 138 | /* Decrement the loop counter */ | |
| 139 | blkCnt--; | |
| 140 | } | |
| 141 | ||
| 142 | /* if (blockSize - 1u) is not multiple of 4 */ | |
| 143 | blkCnt = (blockSize - 1u) % 4u; | |
| 144 | ||
| 145 | #else | |
| 146 | ||
| 147 | /* Run the below code for Cortex-M0 */ | |
| 148 | float32_t maxVal1, out; /* Temporary variables to store the output value. */ | |
| 149 | uint32_t blkCnt, outIndex; /* loop counter */ | |
| 150 | ||
| 151 | /* Initialise the index value to zero. */ | |
| 152 | outIndex = 0u; | |
| 153 | /* Load first input value that act as reference value for comparision */ | |
| 154 | out = *pSrc++; | |
| 155 | ||
| 156 | blkCnt = (blockSize - 1u); | |
| 157 | ||
| 158 | #endif /* #ifndef ARM_MATH_CM0_FAMILY */ | |
| 159 | ||
| 160 | while(blkCnt > 0u) | |
| 161 | { | |
| 162 | /* Initialize maxVal to the next consecutive values one by one */ | |
| 163 | maxVal1 = *pSrc++; | |
| 164 | ||
| 165 | /* compare for the maximum value */ | |
| 166 | if(out < maxVal1) | |
| 167 | { | |
| 168 | /* Update the maximum value and it's index */ | |
| 169 | out = maxVal1; | |
| 170 | outIndex = blockSize - blkCnt; | |
| 171 | } | |
| 172 | ||
| 173 | ||
| 174 | /* Decrement the loop counter */ | |
| 175 | blkCnt--; | |
| 176 | ||
| 177 | } | |
| 178 | ||
| 179 | /* Store the maximum value and it's index into destination pointers */ | |
| 180 | *pResult = out; | |
| 181 | *pIndex = outIndex; | |
| 182 | } | |
| 183 | ||
| 184 | /** | |
| 185 | * @} end of Max group | |
| 186 | */ | |
