source: S-port/trunk/Drivers/CMSIS/DSP/Source/StatisticsFunctions/arm_power_f32.c

Last change on this file was 1, checked in by AlexLir, 3 years ago
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Line 
1/* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_power_f32.c
4 * Description: Sum of the squares of the elements of a floating-point vector
5 *
6 * $Date: 27. January 2017
7 * $Revision: V.1.5.1
8 *
9 * Target Processor: Cortex-M cores
10 * -------------------------------------------------------------------- */
11/*
12 * Copyright (C) 2010-2017 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 "arm_math.h"
30
31/**
32 * @ingroup groupStats
33 */
34
35/**
36 * @defgroup power Power
37 *
38 * Calculates the sum of the squares of the elements in the input vector.
39 * The underlying algorithm is used:
40 *
41 * <pre>
42 * Result = pSrc[0] * pSrc[0] + pSrc[1] * pSrc[1] + pSrc[2] * pSrc[2] + ... + pSrc[blockSize-1] * pSrc[blockSize-1];
43 * </pre>
44 *
45 * There are separate functions for floating point, Q31, Q15, and Q7 data types.
46 */
47
48/**
49 * @addtogroup power
50 * @{
51 */
52
53
54/**
55 * @brief Sum of the squares of the elements of a floating-point vector.
56 * @param[in] *pSrc points to the input vector
57 * @param[in] blockSize length of the input vector
58 * @param[out] *pResult sum of the squares value returned here
59 * @return none.
60 *
61 */
62
63
64void arm_power_f32(
65 float32_t * pSrc,
66 uint32_t blockSize,
67 float32_t * pResult)
68{
69 float32_t sum = 0.0f; /* accumulator */
70 float32_t in; /* Temporary variable to store input value */
71 uint32_t blkCnt; /* loop counter */
72
73#if defined (ARM_MATH_DSP)
74 /* Run the below code for Cortex-M4 and Cortex-M3 */
75
76 /*loop Unrolling */
77 blkCnt = blockSize >> 2U;
78
79 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
80 ** a second loop below computes the remaining 1 to 3 samples. */
81 while (blkCnt > 0U)
82 {
83 /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
84 /* Compute Power and then store the result in a temporary variable, sum. */
85 in = *pSrc++;
86 sum += in * in;
87 in = *pSrc++;
88 sum += in * in;
89 in = *pSrc++;
90 sum += in * in;
91 in = *pSrc++;
92 sum += in * in;
93
94 /* Decrement the loop counter */
95 blkCnt--;
96 }
97
98 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
99 ** No loop unrolling is used. */
100 blkCnt = blockSize % 0x4U;
101
102
103#else
104 /* Run the below code for Cortex-M0 */
105
106 /* Loop over blockSize number of values */
107 blkCnt = blockSize;
108
109#endif /* #if defined (ARM_MATH_DSP) */
110
111
112 while (blkCnt > 0U)
113 {
114 /* C = A[0] * A[0] + A[1] * A[1] + A[2] * A[2] + ... + A[blockSize-1] * A[blockSize-1] */
115 /* compute power and then store the result in a temporary variable, sum. */
116 in = *pSrc++;
117 sum += in * in;
118
119 /* Decrement the loop counter */
120 blkCnt--;
121 }
122
123 /* Store the result to the destination */
124 *pResult = sum;
125}
126
127/**
128 * @} end of power group
129 */
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