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 @return none
46
47 @par Conditions for optimum performance
48 Input and output buffers should be aligned by 32-bit
49 @par Scaling and Overflow Behavior
50 The function uses saturating arithmetic.
51 The Q15 value -1 (0x8000) is saturated to the maximum allowable positive value 0x7FFF.
52 */
53 #if defined(ARM_MATH_MVEI) && !defined(ARM_MATH_AUTOVECTORIZE)
54
55 #include "arm_helium_utils.h"
56
arm_negate_q15(const q15_t * pSrc,q15_t * pDst,uint32_t blockSize)57 void arm_negate_q15(
58 const q15_t * pSrc,
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
71 * Negate and then store the results in the destination buffer.
72 */
73 vecSrc = vld1q(pSrc);
74 vst1q(pDst, vqnegq(vecSrc));
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, vqnegq(vecSrc), p0);
94 }
95 }
96
97 #else
arm_negate_q15(const q15_t * pSrc,q15_t * pDst,uint32_t blockSize)98 void arm_negate_q15(
99 const q15_t * pSrc,
100 q15_t * pDst,
101 uint32_t blockSize)
102 {
103 uint32_t blkCnt; /* Loop counter */
104 q15_t in; /* Temporary input variable */
105
106 #if defined (ARM_MATH_LOOPUNROLL)
107
108 #if defined (ARM_MATH_DSP)
109 q31_t in1; /* Temporary input variables */
110 #endif
111
112 /* Loop unrolling: Compute 4 outputs at a time */
113 blkCnt = blockSize >> 2U;
114
115 while (blkCnt > 0U)
116 {
117 /* C = -A */
118
119 #if defined (ARM_MATH_DSP)
120 /* Negate and store result in destination buffer (2 samples at a time). */
121 in1 = read_q15x2_ia ((q15_t **) &pSrc);
122 write_q15x2_ia (&pDst, __QSUB16(0, in1));
123
124 in1 = read_q15x2_ia ((q15_t **) &pSrc);
125 write_q15x2_ia (&pDst, __QSUB16(0, in1));
126 #else
127 in = *pSrc++;
128 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
129
130 in = *pSrc++;
131 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
132
133 in = *pSrc++;
134 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
135
136 in = *pSrc++;
137 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
138 #endif
139
140 /* Decrement loop counter */
141 blkCnt--;
142 }
143
144 /* Loop unrolling: Compute remaining outputs */
145 blkCnt = blockSize % 0x4U;
146
147 #else
148
149 /* Initialize blkCnt with number of samples */
150 blkCnt = blockSize;
151
152 #endif /* #if defined (ARM_MATH_LOOPUNROLL) */
153
154 while (blkCnt > 0U)
155 {
156 /* C = -A */
157
158 /* Negate and store result in destination buffer. */
159 in = *pSrc++;
160 *pDst++ = (in == (q15_t) 0x8000) ? (q15_t) 0x7fff : -in;
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
