1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_negate_q7.c
4 * Description: Negates Q7 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 Q7 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 Scaling and Overflow Behavior
47 The function uses saturating arithmetic.
48 The Q7 value -1 (0x80) is saturated to the maximum allowable positive value 0x7F.
49 */
50 #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
51
52 #include "arm_helium_utils.h"
53
arm_negate_q7(const q7_t * pSrc,q7_t * pDst,uint32_t blockSize)54 ARM_DSP_ATTRIBUTE void arm_negate_q7(
55 const q7_t * pSrc,
56 q7_t * pDst,
57 uint32_t blockSize)
58 {
59 uint32_t blkCnt; /* loop counters */
60 q7x16_t vecSrc;
61
62 /* Compute 16 outputs at a time */
63 blkCnt = blockSize >> 4;
64 while (blkCnt > 0U)
65 {
66 /*
67 * C = -A
68 * Negate and then store the results in the destination buffer.
69 */
70 vecSrc = vld1q(pSrc);
71 vst1q(pDst, vqnegq(vecSrc));
72 /*
73 * Decrement the blockSize loop counter
74 */
75 blkCnt--;
76 /*
77 * advance vector source and destination pointers
78 */
79 pSrc += 16;
80 pDst += 16;
81 }
82 /*
83 * tail
84 */
85 blkCnt = blockSize & 0xF;
86 if (blkCnt > 0U)
87 {
88 mve_pred16_t p0 = vctp8q(blkCnt);
89 vecSrc = vld1q(pSrc);
90 vstrbq_p(pDst, vqnegq(vecSrc), p0);
91 }
92 }
93
94 #else
arm_negate_q7(const q7_t * pSrc,q7_t * pDst,uint32_t blockSize)95 ARM_DSP_ATTRIBUTE void arm_negate_q7(
96 const q7_t * pSrc,
97 q7_t * pDst,
98 uint32_t blockSize)
99 {
100 uint32_t blkCnt; /* Loop counter */
101 q7_t in; /* Temporary input variable */
102
103 #if defined (ARM_MATH_LOOPUNROLL)
104
105 #if defined (ARM_MATH_DSP)
106 q31_t in1; /* Temporary input variable */
107 #endif
108
109 /* Loop unrolling: Compute 4 outputs at a time */
110 blkCnt = blockSize >> 2U;
111
112 while (blkCnt > 0U)
113 {
114 /* C = -A */
115
116 #if defined (ARM_MATH_DSP)
117 /* Negate and store result in destination buffer (4 samples at a time). */
118 in1 = read_q7x4_ia (&pSrc);
119 write_q7x4_ia (&pDst, __QSUB8(0, in1));
120 #else
121 in = *pSrc++;
122 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
123
124 in = *pSrc++;
125 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
126
127 in = *pSrc++;
128 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
129
130 in = *pSrc++;
131 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
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 */
151
152 /* Negate and store result in destination buffer. */
153 in = *pSrc++;
154
155 #if defined (ARM_MATH_DSP)
156 *pDst++ = (q7_t) __QSUB8(0, in);
157 #else
158 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
159 #endif
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
