1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_negate_q15.c
4 * Description: Negates Q15 vectors
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 BasicNegate
37 @{
38 */
39
40 /**
41 @brief Negates the elements of a Q15 vector.
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 Conditions for optimum performance
47 Input and output buffers should be aligned by 32-bit
48 @par Scaling and Overflow Behavior
49 The function uses saturating arithmetic.
50 The Q15 value -1 (0x8000) is saturated to the maximum allowable positive value 0x7FFF.
51 */
52 #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
53
54 #include "arm_helium_utils.h"
55
arm_negate_q15(const q15_t * pSrc,q15_t * pDst,uint32_t blockSize)56 ARM_DSP_ATTRIBUTE void arm_negate_q15(
57 const q15_t * pSrc,
58 q15_t * pDst,
59 uint32_t blockSize)
60 {
61 uint32_t blkCnt; /* loop counters */
62 q15x8_t vecSrc;
63
64 /* Compute 8 outputs at a time */
65 blkCnt = blockSize >> 3;
66 while (blkCnt > 0U)
67 {
68 /*
69 * C = -A
70 * Negate and then store the results in the destination buffer.
71 */
72 vecSrc = vld1q(pSrc);
73 vst1q(pDst, vqnegq(vecSrc));
74 /*
75 * Decrement the blockSize loop counter
76 */
77 blkCnt--;
78 /*
79 * advance vector source and destination pointers
80 */
81 pSrc += 8;
82 pDst += 8;
83 }
84 /*
85 * tail
86 */
87 blkCnt = blockSize & 7;
88 if (blkCnt > 0U)
89 {
90 mve_pred16_t p0 = vctp16q(blkCnt);
91 vecSrc = vld1q(pSrc);
92 vstrhq_p(pDst, vqnegq(vecSrc), p0);
93 }
94 }
95
96 #else
arm_negate_q15(const q15_t * pSrc,q15_t * pDst,uint32_t blockSize)97 ARM_DSP_ATTRIBUTE void arm_negate_q15(
98 const q15_t * pSrc,
99 q15_t * pDst,
100 uint32_t blockSize)
101 {
102 uint32_t blkCnt; /* Loop counter */
103 q15_t in; /* Temporary input variable */
104
105 #if defined (ARM_MATH_LOOPUNROLL)
106
107 #if defined (ARM_MATH_DSP)
108 q31_t in1; /* Temporary input variables */
109 #endif
110
111 /* Loop unrolling: Compute 4 outputs at a time */
112 blkCnt = blockSize >> 2U;
113
114 while (blkCnt > 0U)
115 {
116 /* C = -A */
117
118 #if defined (ARM_MATH_DSP)
119 /* Negate and store result in destination buffer (2 samples at a time). */
120 in1 = read_q15x2_ia (&pSrc);
121 write_q15x2_ia (&pDst, __QSUB16(0, in1));
122
123 in1 = read_q15x2_ia (&pSrc);
124 write_q15x2_ia (&pDst, __QSUB16(0, in1));
125 #else
126 in = *pSrc++;
127 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
128
129 in = *pSrc++;
130 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
131
132 in = *pSrc++;
133 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
134
135 in = *pSrc++;
136 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
137 #endif
138
139 /* Decrement loop counter */
140 blkCnt--;
141 }
142
143 /* Loop unrolling: Compute remaining outputs */
144 blkCnt = blockSize % 0x4U;
145
146 #else
147
148 /* Initialize blkCnt with number of samples */
149 blkCnt = blockSize;
150
151 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
152
153 while (blkCnt > 0U)
154 {
155 /* C = -A */
156
157 /* Negate and store result in destination buffer. */
158 in = *pSrc++;
159 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
160
161 /* Decrement loop counter */
162 blkCnt--;
163 }
164
165 }
166 #endif /* defined(ARM_MATH_MVEI) */
167
168 /**
169 @} end of BasicNegate group
170 */
171
