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 */
47
48 #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
49
50 #include "arm_helium_utils.h"
51
arm_max_no_idx_q15(const q15_t * pSrc,uint32_t blockSize,q15_t * pResult)52 void arm_max_no_idx_q15(
53 const q15_t * pSrc,
54 uint32_t blockSize,
55 q15_t * pResult)
56 {
57 int32_t blkCnt; /* loop counters */
58 q15x8_t vecSrc;
59 q15_t const *pSrcVec;
60 q15x8_t curExtremValVec = vdupq_n_s16(Q15_MIN);
61 q15_t maxValue = Q15_MIN;
62 mve_pred16_t p0;
63
64
65 pSrcVec = (q15_t const *) pSrc;
66 blkCnt = blockSize >> 3;
67 while (blkCnt > 0)
68 {
69 vecSrc = vld1q(pSrcVec);
70 pSrcVec += 8;
71 /*
72 * update per-lane max.
73 */
74 curExtremValVec = vmaxq(vecSrc, curExtremValVec);
75 /*
76 * Decrement the blockSize loop counter
77 */
78 blkCnt--;
79 }
80 /*
81 * tail
82 * (will be merged thru tail predication)
83 */
84 blkCnt = blockSize & 7;
85 if (blkCnt > 0)
86 {
87 vecSrc = vld1q(pSrcVec);
88 pSrcVec += 8;
89 p0 = vctp16q(blkCnt);
90 /*
91 * Get current max per lane and current index per lane
92 * when a max is selected
93 */
94 curExtremValVec = vmaxq_m(curExtremValVec, vecSrc, curExtremValVec, p0);
95 }
96 /*
97 * Get max value across the vector
98 */
99 maxValue = vmaxvq(maxValue, curExtremValVec);
100 *pResult = maxValue;
101 }
102
103 #else
arm_max_no_idx_q15(const q15_t * pSrc,uint32_t blockSize,q15_t * pResult)104 void arm_max_no_idx_q15(
105 const q15_t * pSrc,
106 uint32_t blockSize,
107 q15_t * pResult)
108 {
109 q15_t maxVal1, out; /* Temporary variables to store the output value. */
110 uint32_t blkCnt; /* loop counter */
111
112 /* Load first input value that act as reference value for comparision */
113 out = *pSrc++;
114
115 blkCnt = (blockSize - 1U);
116
117
118 while (blkCnt > 0U)
119 {
120 /* Initialize maxVal to the next consecutive values one by one */
121 maxVal1 = *pSrc++;
122
123 /* compare for the maximum value */
124 if (out < maxVal1)
125 {
126 /* Update the maximum value */
127 out = maxVal1;
128 }
129
130 /* Decrement the loop counter */
131 blkCnt--;
132 }
133
134 /* Store the maximum value into destination pointer */
135 *pResult = out;
136 }
137
138 #endif /* #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE) */
139 /**
140 @} end of Max group
141 */
142
