source: S-port/trunk/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_abs_f32.c

Last change on this file was 1, checked in by AlexLir, 3 years ago
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1/* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_abs_f32.c
4 * Description: Floating-point vector absolute value
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#include <math.h>
31
32/**
33 * @ingroup groupMath
34 */
35
36/**
37 * @defgroup BasicAbs Vector Absolute Value
38 *
39 * Computes the absolute value of a vector on an element-by-element basis.
40 *
41 * <pre>
42 * pDst[n] = abs(pSrc[n]), 0 <= n < blockSize.
43 * </pre>
44 *
45 * The functions support in-place computation allowing the source and
46 * destination pointers to reference the same memory buffer.
47 * There are separate functions for floating-point, Q7, Q15, and Q31 data types.
48 */
49
50/**
51 * @addtogroup BasicAbs
52 * @{
53 */
54
55/**
56 * @brief Floating-point vector absolute value.
57 * @param[in] *pSrc points to the input buffer
58 * @param[out] *pDst points to the output buffer
59 * @param[in] blockSize number of samples in each vector
60 * @return none.
61 */
62
63void arm_abs_f32(
64 float32_t * pSrc,
65 float32_t * pDst,
66 uint32_t blockSize)
67{
68 uint32_t blkCnt; /* loop counter */
69
70#if defined (ARM_MATH_DSP)
71
72 /* Run the below code for Cortex-M4 and Cortex-M3 */
73 float32_t in1, in2, in3, in4; /* temporary variables */
74
75 /*loop Unrolling */
76 blkCnt = blockSize >> 2U;
77
78 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
79 ** a second loop below computes the remaining 1 to 3 samples. */
80 while (blkCnt > 0U)
81 {
82 /* C = |A| */
83 /* Calculate absolute and then store the results in the destination buffer. */
84 /* read sample from source */
85 in1 = *pSrc;
86 in2 = *(pSrc + 1);
87 in3 = *(pSrc + 2);
88
89 /* find absolute value */
90 in1 = fabsf(in1);
91
92 /* read sample from source */
93 in4 = *(pSrc + 3);
94
95 /* find absolute value */
96 in2 = fabsf(in2);
97
98 /* read sample from source */
99 *pDst = in1;
100
101 /* find absolute value */
102 in3 = fabsf(in3);
103
104 /* find absolute value */
105 in4 = fabsf(in4);
106
107 /* store result to destination */
108 *(pDst + 1) = in2;
109
110 /* store result to destination */
111 *(pDst + 2) = in3;
112
113 /* store result to destination */
114 *(pDst + 3) = in4;
115
116
117 /* Update source pointer to process next sampels */
118 pSrc += 4U;
119
120 /* Update destination pointer to process next sampels */
121 pDst += 4U;
122
123 /* Decrement the loop counter */
124 blkCnt--;
125 }
126
127 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
128 ** No loop unrolling is used. */
129 blkCnt = blockSize % 0x4U;
130
131#else
132
133 /* Run the below code for Cortex-M0 */
134
135 /* Initialize blkCnt with number of samples */
136 blkCnt = blockSize;
137
138#endif /* #if defined (ARM_MATH_DSP) */
139
140 while (blkCnt > 0U)
141 {
142 /* C = |A| */
143 /* Calculate absolute and then store the results in the destination buffer. */
144 *pDst++ = fabsf(*pSrc++);
145
146 /* Decrement the loop counter */
147 blkCnt--;
148 }
149}
150
151/**
152 * @} end of BasicAbs group
153 */
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