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 @return none
46
47 @par Scaling and Overflow Behavior
48 The function uses saturating arithmetic.
49 The Q7 value -1 (0x80) is saturated to the maximum allowable positive value 0x7F.
50 */
51 #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
52
53 #include "arm_helium_utils.h"
54
arm_negate_q7(const q7_t * pSrc,q7_t * pDst,uint32_t blockSize)55 void arm_negate_q7(
56 const q7_t * pSrc,
57 q7_t * pDst,
58 uint32_t blockSize)
59 {
60 uint32_t blkCnt; /* loop counters */
61 q7x16_t vecSrc;
62
63 /* Compute 16 outputs at a time */
64 blkCnt = blockSize >> 4;
65 while (blkCnt > 0U)
66 {
67 /*
68 * C = -A
69 * Negate and then store the results in the destination buffer.
70 */
71 vecSrc = vld1q(pSrc);
72 vst1q(pDst, vqnegq(vecSrc));
73 /*
74 * Decrement the blockSize loop counter
75 */
76 blkCnt--;
77 /*
78 * advance vector source and destination pointers
79 */
80 pSrc += 16;
81 pDst += 16;
82 }
83 /*
84 * tail
85 */
86 blkCnt = blockSize & 0xF;
87 if (blkCnt > 0U)
88 {
89 mve_pred16_t p0 = vctp8q(blkCnt);
90 vecSrc = vld1q(pSrc);
91 vstrbq_p(pDst, vqnegq(vecSrc), p0);
92 }
93 }
94
95 #else
arm_negate_q7(const q7_t * pSrc,q7_t * pDst,uint32_t blockSize)96 void arm_negate_q7(
97 const q7_t * pSrc,
98 q7_t * pDst,
99 uint32_t blockSize)
100 {
101 uint32_t blkCnt; /* Loop counter */
102 q7_t in; /* Temporary input variable */
103
104 #if defined (ARM_MATH_LOOPUNROLL)
105
106 #if defined (ARM_MATH_DSP)
107 q31_t in1; /* Temporary input variable */
108 #endif
109
110 /* Loop unrolling: Compute 4 outputs at a time */
111 blkCnt = blockSize >> 2U;
112
113 while (blkCnt > 0U)
114 {
115 /* C = -A */
116
117 #if defined (ARM_MATH_DSP)
118 /* Negate and store result in destination buffer (4 samples at a time). */
119 in1 = read_q7x4_ia ((q7_t **) &pSrc);
120 write_q7x4_ia (&pDst, __QSUB8(0, in1));
121 #else
122 in = *pSrc++;
123 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
124
125 in = *pSrc++;
126 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
127
128 in = *pSrc++;
129 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
130
131 in = *pSrc++;
132 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
133 #endif
134
135 /* Decrement loop counter */
136 blkCnt--;
137 }
138
139 /* Loop unrolling: Compute remaining outputs */
140 blkCnt = blockSize % 0x4U;
141
142 #else
143
144 /* Initialize blkCnt with number of samples */
145 blkCnt = blockSize;
146
147 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
148
149 while (blkCnt > 0U)
150 {
151 /* C = -A */
152
153 /* Negate and store result in destination buffer. */
154 in = *pSrc++;
155
156 #if defined (ARM_MATH_DSP)
157 *pDst++ = (q7_t) __QSUB8(0, in);
158 #else
159 *pDst++ = (in == (q7_t) 0x80) ? (q7_t) 0x7f : -in;
160 #endif
161
162 /* Decrement loop counter */
163 blkCnt--;
164 }
165
166 }
167 #endif /* defined(ARM_MATH_MVEI) */
168
169 /**
170 @} end of BasicNegate group
171 */
172
