1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_max_no_idx_f32.c
4 * Description: Maximum value of a floating-point vector without returning the index
5 *
6 * $Date: 23 April 2021
7 * $Revision: V1.9.0
8 *
9 * Target Processor: Cortex-M and Cortex-A cores
10 * -------------------------------------------------------------------- */
11 /*
12 * Copyright (C) 2010-2021 ARM Limited or its affiliates. All rights reserved.
13 *
14 * SPDX-License-Identifier: Apache-2.0
15 *
16 * Licensed under the Apache License, Version 2.0 (the License); you may
17 * not use this file except in compliance with the License.
18 * You may obtain a copy of the License at
19 *
20 * www.apache.org/licenses/LICENSE-2.0
21 *
22 * Unless required by applicable law or agreed to in writing, software
23 * distributed under the License is distributed on an AS IS BASIS, WITHOUT
24 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
25 * See the License for the specific language governing permissions and
26 * limitations under the License.
27 */
28
29 #include "dsp/statistics_functions.h"
30 #if (defined(ARM_MATH_NEON) || defined(ARM_MATH_MVEF)) && !defined(ARM_MATH_AUTOVECTORIZE)
31 #include <limits.h>
32 #endif
33
34 /**
35 @ingroup groupStats
36 */
37
38
39 /**
40 @addtogroup Max
41 @{
42 */
43
44 /**
45 @brief Maximum value of a floating-point vector.
46 @param[in] pSrc points to the input vector
47 @param[in] blockSize number of samples in input vector
48 @param[out] pResult maximum value returned here
49 @return none
50 */
51
52 #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
53
arm_max_no_idx_f32(const float32_t * pSrc,uint32_t blockSize,float32_t * pResult)54 void arm_max_no_idx_f32(
55 const float32_t *pSrc,
56 uint32_t blockSize,
57 float32_t *pResult)
58 {
59 f32x4_t vecSrc;
60 f32x4_t curExtremValVec = vdupq_n_f32(F32_MIN);
61 float32_t maxValue = F32_MIN;
62 float32_t newVal;
63 uint32_t blkCnt;
64
65 /* Loop unrolling: Compute 4 outputs at a time */
66 blkCnt = blockSize >> 2U;
67
68 while (blkCnt > 0U)
69 {
70
71 vecSrc = vldrwq_f32(pSrc);
72 /*
73 * update per-lane max.
74 */
75 curExtremValVec = vmaxnmq(vecSrc, curExtremValVec);
76 /*
77 * Decrement the blockSize loop counter
78 * Advance vector source and destination pointers
79 */
80 pSrc += 4;
81 blkCnt --;
82 }
83 /*
84 * Get max value across the vector
85 */
86 maxValue = vmaxnmvq(maxValue, curExtremValVec);
87
88 blkCnt = blockSize & 3;
89
90 while (blkCnt > 0U)
91 {
92 newVal = *pSrc++;
93
94 /* compare for the maximum value */
95 if (maxValue < newVal)
96 {
97 /* Update the maximum value and it's index */
98 maxValue = newVal;
99 }
100
101 blkCnt --;
102 }
103
104 *pResult = maxValue;
105 }
106
107 #else
108
arm_max_no_idx_f32(const float32_t * pSrc,uint32_t blockSize,float32_t * pResult)109 void arm_max_no_idx_f32(
110 const float32_t *pSrc,
111 uint32_t blockSize,
112 float32_t *pResult)
113 {
114 float32_t maxValue = F32_MIN;
115 float32_t newVal;
116
117 while (blockSize > 0U)
118 {
119 newVal = *pSrc++;
120
121 /* compare for the maximum value */
122 if (maxValue < newVal)
123 {
124 /* Update the maximum value and it's index */
125 maxValue = newVal;
126 }
127
128 blockSize --;
129 }
130
131 *pResult = maxValue;
132 }
133
134 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
135
136 /**
137 @} end of Max group
138 */
139