source: S-port/trunk/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_offset_q31.c

Last change on this file was 1, checked in by AlexLir, 3 years ago
File size: 3.3 KB
Line 
1/* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_offset_q31.c
4 * Description: Q31 vector offset
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 groupMath
33 */
34
35/**
36 * @addtogroup offset
37 * @{
38 */
39
40/**
41 * @brief Adds a constant offset to a Q31 vector.
42 * @param[in] *pSrc points to the input vector
43 * @param[in] offset is the offset to be added
44 * @param[out] *pDst points to the output vector
45 * @param[in] blockSize number of samples in the vector
46 * @return none.
47 *
48 * <b>Scaling and Overflow Behavior:</b>
49 * \par
50 * The function uses saturating arithmetic.
51 * Results outside of the allowable Q31 range [0x80000000 0x7FFFFFFF] are saturated.
52 */
53
54void arm_offset_q31(
55 q31_t * pSrc,
56 q31_t offset,
57 q31_t * pDst,
58 uint32_t blockSize)
59{
60 uint32_t blkCnt; /* loop counter */
61
62#if defined (ARM_MATH_DSP)
63
64/* Run the below code for Cortex-M4 and Cortex-M3 */
65 q31_t in1, in2, in3, in4;
66
67
68 /*loop Unrolling */
69 blkCnt = blockSize >> 2U;
70
71 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
72 ** a second loop below computes the remaining 1 to 3 samples. */
73 while (blkCnt > 0U)
74 {
75 /* C = A + offset */
76 /* Add offset and then store the results in the destination buffer. */
77 in1 = *pSrc++;
78 in2 = *pSrc++;
79 in3 = *pSrc++;
80 in4 = *pSrc++;
81
82 *pDst++ = __QADD(in1, offset);
83 *pDst++ = __QADD(in2, offset);
84 *pDst++ = __QADD(in3, offset);
85 *pDst++ = __QADD(in4, offset);
86
87 /* Decrement the loop counter */
88 blkCnt--;
89 }
90
91 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
92 ** No loop unrolling is used. */
93 blkCnt = blockSize % 0x4U;
94
95 while (blkCnt > 0U)
96 {
97 /* C = A + offset */
98 /* Add offset and then store the result in the destination buffer. */
99 *pDst++ = __QADD(*pSrc++, offset);
100
101 /* Decrement the loop counter */
102 blkCnt--;
103 }
104
105#else
106
107 /* Run the below code for Cortex-M0 */
108
109 /* Initialize blkCnt with number of samples */
110 blkCnt = blockSize;
111
112 while (blkCnt > 0U)
113 {
114 /* C = A + offset */
115 /* Add offset and then store the result in the destination buffer. */
116 *pDst++ = (q31_t) clip_q63_to_q31((q63_t) * pSrc++ + offset);
117
118 /* Decrement the loop counter */
119 blkCnt--;
120 }
121
122#endif /* #if defined (ARM_MATH_DSP) */
123
124}
125
126/**
127 * @} end of offset group
128 */
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