1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_abs_q15.c
4 * Description: Q15 vector absolute value
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 BasicAbs
37 @{
38 */
39
40 /**
41 @brief Q15 vector absolute value.
42 @param[in] pSrc points to the input vector
43 @param[out] pDst points to the output vector
44 @param[in] blockSize number of samples in each vector
45
46 @par Scaling and Overflow Behavior
47 The function uses saturating arithmetic.
48 The Q15 value -1 (0x8000) will be saturated to the maximum allowable positive value 0x7FFF.
49 */
50
51 #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
52
53 #include "arm_helium_utils.h"
54
arm_abs_q15(const q15_t * pSrc,q15_t * pDst,uint32_t blockSize)55 void arm_abs_q15(
56 const q15_t * pSrc,
57 q15_t * pDst,
58 uint32_t blockSize)
59 {
60 uint32_t blkCnt; /* loop counters */
61 q15x8_t vecSrc;
62
63 /* Compute 8 outputs at a time */
64 blkCnt = blockSize >> 3;
65 while (blkCnt > 0U)
66 {
67 /*
68 * C = |A|
69 * Calculate absolute and then store the results in the destination buffer.
70 */
71 vecSrc = vld1q(pSrc);
72 vst1q(pDst, vqabsq(vecSrc));
73 /*
74 * Decrement the blockSize loop counter
75 */
76 blkCnt--;
77 /*
78 * advance vector source and destination pointers
79 */
80 pSrc += 8;
81 pDst += 8;
82 }
83 /*
84 * tail
85 */
86 blkCnt = blockSize & 7;
87 if (blkCnt > 0U)
88 {
89 mve_pred16_t p0 = vctp16q(blkCnt);
90 vecSrc = vld1q(pSrc);
91 vstrhq_p(pDst, vqabsq(vecSrc), p0);
92 }
93 }
94
95 #else
arm_abs_q15(const q15_t * pSrc,q15_t * pDst,uint32_t blockSize)96 void arm_abs_q15(
97 const q15_t * pSrc,
98 q15_t * pDst,
99 uint32_t blockSize)
100 {
101 uint32_t blkCnt; /* Loop counter */
102 q15_t in; /* Temporary input variable */
103
104 #if defined (ARM_MATH_LOOPUNROLL)
105
106 /* Loop unrolling: Compute 4 outputs at a time */
107 blkCnt = blockSize >> 2U;
108
109 while (blkCnt > 0U)
110 {
111 /* C = |A| */
112
113 /* Calculate absolute of input (if -1 then saturated to 0x7fff) and store result in destination buffer. */
114 in = *pSrc++;
115 #if defined (ARM_MATH_DSP)
116 *pDst++ = (in > 0) ? in : (q15_t)__QSUB16(0, in);
117 #else
118 *pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in);
119 #endif
120
121 in = *pSrc++;
122 #if defined (ARM_MATH_DSP)
123 *pDst++ = (in > 0) ? in : (q15_t)__QSUB16(0, in);
124 #else
125 *pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in);
126 #endif
127
128 in = *pSrc++;
129 #if defined (ARM_MATH_DSP)
130 *pDst++ = (in > 0) ? in : (q15_t)__QSUB16(0, in);
131 #else
132 *pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in);
133 #endif
134
135 in = *pSrc++;
136 #if defined (ARM_MATH_DSP)
137 *pDst++ = (in > 0) ? in : (q15_t)__QSUB16(0, in);
138 #else
139 *pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in);
140 #endif
141
142 /* Decrement loop counter */
143 blkCnt--;
144 }
145
146 /* Loop unrolling: Compute remaining outputs */
147 blkCnt = blockSize % 0x4U;
148
149 #else
150
151 /* Initialize blkCnt with number of samples */
152 blkCnt = blockSize;
153
154 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
155
156 while (blkCnt > 0U)
157 {
158 /* C = |A| */
159
160 /* Calculate absolute of input (if -1 then saturated to 0x7fff) and store result in destination buffer. */
161 in = *pSrc++;
162 #if defined (ARM_MATH_DSP)
163 *pDst++ = (in > 0) ? in : (q15_t)__QSUB16(0, in);
164 #else
165 *pDst++ = (in > 0) ? in : ((in == (q15_t) 0x8000) ? 0x7fff : -in);
166 #endif
167
168 /* Decrement loop counter */
169 blkCnt--;
170 }
171
172 }
173 #endif /* defined(ARM_MATH_MVEI) */
174
175 /**
176 @} end of BasicAbs group
177 */
178
