source: S-port/trunk/Drivers/CMSIS/DSP/Source/BasicMathFunctions/arm_offset_q7.c

Last change on this file was 1, checked in by AlexLir, 3 years ago
File size: 3.4 KB
Line 
1/* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_offset_q7.c
4 * Description: Q7 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 Q7 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 Q7 range [0x80 0x7F] are saturated.
52 */
53
54void arm_offset_q7(
55 q7_t * pSrc,
56 q7_t offset,
57 q7_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 offset_packed; /* Offset packed to 32 bit */
66
67
68 /*loop Unrolling */
69 blkCnt = blockSize >> 2U;
70
71 /* Offset is packed to 32 bit in order to use SIMD32 for addition */
72 offset_packed = __PACKq7(offset, offset, offset, offset);
73
74 /* First part of the processing with loop unrolling. Compute 4 outputs at a time.
75 ** a second loop below computes the remaining 1 to 3 samples. */
76 while (blkCnt > 0U)
77 {
78 /* C = A + offset */
79 /* Add offset and then store the results in the destination bufferfor 4 samples at a time. */
80 *__SIMD32(pDst)++ = __QADD8(*__SIMD32(pSrc)++, offset_packed);
81
82 /* Decrement the loop counter */
83 blkCnt--;
84 }
85
86 /* If the blockSize is not a multiple of 4, compute any remaining output samples here.
87 ** No loop unrolling is used. */
88 blkCnt = blockSize % 0x4U;
89
90 while (blkCnt > 0U)
91 {
92 /* C = A + offset */
93 /* Add offset and then store the result in the destination buffer. */
94 *pDst++ = (q7_t) __SSAT(*pSrc++ + offset, 8);
95
96 /* Decrement the loop counter */
97 blkCnt--;
98 }
99
100#else
101
102 /* Run the below code for Cortex-M0 */
103
104 /* Initialize blkCnt with number of samples */
105 blkCnt = blockSize;
106
107 while (blkCnt > 0U)
108 {
109 /* C = A + offset */
110 /* Add offset and then store the result in the destination buffer. */
111 *pDst++ = (q7_t) __SSAT((q15_t) * pSrc++ + offset, 8);
112
113 /* Decrement the loop counter */
114 blkCnt--;
115 }
116
117#endif /* #if defined (ARM_MATH_DSP) */
118
119}
120
121/**
122 * @} end of offset group
123 */
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