1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_offset_q15.c
4 * Description: Q15 vector offset
5 *
6 * $Date: 23 April 2021
7 * $Revision: V1.9.0
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/basic_math_functions.h"
30
31 /**
32 @ingroup groupMath
33 */
34
35 /**
36 @addtogroup BasicOffset
37 @{
38 */
39
40 /**
41 @brief Adds a constant offset to a Q15 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 each vector
46 @return none
47
48 @par Scaling and Overflow Behavior
49 The function uses saturating arithmetic.
50 Results outside of the allowable Q15 range [0x8000 0x7FFF] are saturated.
51 */
52 #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
53
54 #include "arm_helium_utils.h"
55
arm_offset_q15(const q15_t * pSrc,q15_t offset,q15_t * pDst,uint32_t blockSize)56 void arm_offset_q15(
57 const q15_t * pSrc,
58 q15_t offset,
59 q15_t * pDst,
60 uint32_t blockSize)
61 {
62 uint32_t blkCnt; /* loop counters */
63 q15x8_t vecSrc;
64
65 /* Compute 8 outputs at a time */
66 blkCnt = blockSize >> 3;
67 while (blkCnt > 0U)
68 {
69 /*
70 * C = A + offset
71 * Add offset and then store the result in the destination buffer.
72 */
73 vecSrc = vld1q(pSrc);
74 vst1q(pDst, vqaddq(vecSrc, offset));
75 /*
76 * Decrement the blockSize loop counter
77 */
78 blkCnt--;
79 /*
80 * advance vector source and destination pointers
81 */
82 pSrc += 8;
83 pDst += 8;
84 }
85 /*
86 * tail
87 */
88 blkCnt = blockSize & 7;
89 if (blkCnt > 0U)
90 {
91 mve_pred16_t p0 = vctp16q(blkCnt);
92 vecSrc = vld1q(pSrc);
93 vstrhq_p(pDst, vqaddq(vecSrc, offset), p0);
94 }
95 }
96
97
98 #else
arm_offset_q15(const q15_t * pSrc,q15_t offset,q15_t * pDst,uint32_t blockSize)99 void arm_offset_q15(
100 const q15_t * pSrc,
101 q15_t offset,
102 q15_t * pDst,
103 uint32_t blockSize)
104 {
105 uint32_t blkCnt; /* Loop counter */
106
107 #if defined (ARM_MATH_LOOPUNROLL)
108
109 #if defined (ARM_MATH_DSP)
110 q31_t offset_packed; /* Offset packed to 32 bit */
111
112 /* Offset is packed to 32 bit in order to use SIMD32 for addition */
113 offset_packed = __PKHBT(offset, offset, 16);
114 #endif
115
116 /* Loop unrolling: Compute 4 outputs at a time */
117 blkCnt = blockSize >> 2U;
118
119 while (blkCnt > 0U)
120 {
121 /* C = A + offset */
122
123 #if defined (ARM_MATH_DSP)
124 /* Add offset and store result in destination buffer (2 samples at a time). */
125 write_q15x2_ia (&pDst, __QADD16(read_q15x2_ia ((q15_t **) &pSrc), offset_packed));
126 write_q15x2_ia (&pDst, __QADD16(read_q15x2_ia ((q15_t **) &pSrc), offset_packed));
127 #else
128 *pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
129 *pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
130 *pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
131 *pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
132 #endif
133
134 /* Decrement loop counter */
135 blkCnt--;
136 }
137
138 /* Loop unrolling: Compute remaining outputs */
139 blkCnt = blockSize % 0x4U;
140
141 #else
142
143 /* Initialize blkCnt with number of samples */
144 blkCnt = blockSize;
145
146 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
147
148 while (blkCnt > 0U)
149 {
150 /* C = A + offset */
151
152 /* Add offset and store result in destination buffer. */
153 #if defined (ARM_MATH_DSP)
154 *pDst++ = (q15_t) __QADD16(*pSrc++, offset);
155 #else
156 *pDst++ = (q15_t) __SSAT(((q31_t) *pSrc++ + offset), 16);
157 #endif
158
159 /* Decrement loop counter */
160 blkCnt--;
161 }
162
163 }
164 #endif /* defined(ARM_MATH_MVEI) */
165
166 /**
167 @} end of BasicOffset group
168 */
169