1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_max_no_idx_q15.c
4 * Description: Maximum value of a q15 vector without returning the index
5 *
6 * $Date: 16 November 2021
7 * $Revision: V1.10.0
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
31
32 /**
33 @ingroup groupStats
34 */
35
36 /**
37 @addtogroup Max
38 @{
39 */
40
41 /**
42 @brief Maximum value of a q15 vector without index.
43 @param[in] pSrc points to the input vector
44 @param[in] blockSize number of samples in input vector
45 @param[out] pResult maximum value returned here
46 @return none
47 */
48
49 #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
50
51 #include "arm_helium_utils.h"
52
arm_max_no_idx_q15(const q15_t * pSrc,uint32_t blockSize,q15_t * pResult)53 void arm_max_no_idx_q15(
54 const q15_t * pSrc,
55 uint32_t blockSize,
56 q15_t * pResult)
57 {
58 int32_t blkCnt; /* loop counters */
59 q15x8_t vecSrc;
60 q15_t const *pSrcVec;
61 q15x8_t curExtremValVec = vdupq_n_s16(Q15_MIN);
62 q15_t maxValue = Q15_MIN;
63 mve_pred16_t p0;
64
65
66 pSrcVec = (q15_t const *) pSrc;
67 blkCnt = blockSize >> 3;
68 while (blkCnt > 0)
69 {
70 vecSrc = vld1q(pSrcVec);
71 pSrcVec += 8;
72 /*
73 * update per-lane max.
74 */
75 curExtremValVec = vmaxq(vecSrc, curExtremValVec);
76 /*
77 * Decrement the blockSize loop counter
78 */
79 blkCnt--;
80 }
81 /*
82 * tail
83 * (will be merged thru tail predication)
84 */
85 blkCnt = blockSize & 7;
86 if (blkCnt > 0)
87 {
88 vecSrc = vld1q(pSrcVec);
89 pSrcVec += 8;
90 p0 = vctp16q(blkCnt);
91 /*
92 * Get current max per lane and current index per lane
93 * when a max is selected
94 */
95 curExtremValVec = vmaxq_m(curExtremValVec, vecSrc, curExtremValVec, p0);
96 }
97 /*
98 * Get max value across the vector
99 */
100 maxValue = vmaxvq(maxValue, curExtremValVec);
101 *pResult = maxValue;
102 }
103
104 #else
arm_max_no_idx_q15(const q15_t * pSrc,uint32_t blockSize,q15_t * pResult)105 void arm_max_no_idx_q15(
106 const q15_t * pSrc,
107 uint32_t blockSize,
108 q15_t * pResult)
109 {
110 q15_t maxVal1, out; /* Temporary variables to store the output value. */
111 uint32_t blkCnt; /* loop counter */
112
113 /* Load first input value that act as reference value for comparision */
114 out = *pSrc++;
115
116 blkCnt = (blockSize - 1U);
117
118
119 while (blkCnt > 0U)
120 {
121 /* Initialize maxVal to the next consecutive values one by one */
122 maxVal1 = *pSrc++;
123
124 /* compare for the maximum value */
125 if (out < maxVal1)
126 {
127 /* Update the maximum value */
128 out = maxVal1;
129 }
130
131 /* Decrement the loop counter */
132 blkCnt--;
133 }
134
135 /* Store the maximum value into destination pointer */
136 *pResult = out;
137 }
138
139 #endif /* #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE) */
140 /**
141 @} end of Max group
142 */
143