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 */
50
51 #if defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE)
52
arm_max_no_idx_f32(const float32_t * pSrc,uint32_t blockSize,float32_t * pResult)53 ARM_DSP_ATTRIBUTE void arm_max_no_idx_f32(
54 const float32_t *pSrc,
55 uint32_t blockSize,
56 float32_t *pResult)
57 {
58 f32x4_t vecSrc;
59 f32x4_t curExtremValVec = vdupq_n_f32(F32_MIN);
60 float32_t maxValue = F32_MIN;
61 float32_t newVal;
62 uint32_t blkCnt;
63
64 /* Loop unrolling: Compute 4 outputs at a time */
65 blkCnt = blockSize >> 2U;
66
67 while (blkCnt > 0U)
68 {
69
70 vecSrc = vldrwq_f32(pSrc);
71 /*
72 * update per-lane max.
73 */
74 curExtremValVec = vmaxnmq(vecSrc, curExtremValVec);
75 /*
76 * Decrement the blockSize loop counter
77 * Advance vector source and destination pointers
78 */
79 pSrc += 4;
80 blkCnt --;
81 }
82 /*
83 * Get max value across the vector
84 */
85 maxValue = vmaxnmvq(maxValue, curExtremValVec);
86
87 blkCnt = blockSize & 3;
88
89 while (blkCnt > 0U)
90 {
91 newVal = *pSrc++;
92
93 /* compare for the maximum value */
94 if (maxValue < newVal)
95 {
96 /* Update the maximum value and it's index */
97 maxValue = newVal;
98 }
99
100 blkCnt --;
101 }
102
103 *pResult = maxValue;
104 }
105
106 #else
107
arm_max_no_idx_f32(const float32_t * pSrc,uint32_t blockSize,float32_t * pResult)108 ARM_DSP_ATTRIBUTE void arm_max_no_idx_f32(
109 const float32_t *pSrc,
110 uint32_t blockSize,
111 float32_t *pResult)
112 {
113 float32_t maxValue = F32_MIN;
114 float32_t newVal;
115
116 while (blockSize > 0U)
117 {
118 newVal = *pSrc++;
119
120 /* compare for the maximum value */
121 if (maxValue < newVal)
122 {
123 /* Update the maximum value and it's index */
124 maxValue = newVal;
125 }
126
127 blockSize --;
128 }
129
130 *pResult = maxValue;
131 }
132
133 #endif /* defined(ARM_MATH_MVEF) && !defined(ARM_MATH_AUTOVECTORIZE) */
134
135 /**
136 @} end of Max group
137 */
138
