1 /* ----------------------------------------------------------------------
2 * Project: CMSIS DSP Library
3 * Title: arm_bitreversal2.c
4 * Description: Bitreversal functions
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) 2019 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/transform_functions.h"
30 #include "arm_common_tables.h"
31
32
33 /**
34 @brief In-place 64 bit reversal function.
35 @param[in,out] pSrc points to in-place buffer of unknown 64-bit data type
36 @param[in] bitRevLen bit reversal table length
37 @param[in] pBitRevTab points to bit reversal table
38 @return none
39 */
40
arm_bitreversal_64(uint64_t * pSrc,const uint16_t bitRevLen,const uint16_t * pBitRevTab)41 void arm_bitreversal_64(
42 uint64_t *pSrc,
43 const uint16_t bitRevLen,
44 const uint16_t *pBitRevTab)
45 {
46 uint64_t a, b, i, tmp;
47
48 for (i = 0; i < bitRevLen; )
49 {
50 a = pBitRevTab[i ] >> 2;
51 b = pBitRevTab[i + 1] >> 2;
52
53 //real
54 tmp = pSrc[a];
55 pSrc[a] = pSrc[b];
56 pSrc[b] = tmp;
57
58 //complex
59 tmp = pSrc[a+1];
60 pSrc[a+1] = pSrc[b+1];
61 pSrc[b+1] = tmp;
62
63 i += 2;
64 }
65 }
66
67 /**
68 @brief In-place 32 bit reversal function.
69 @param[in,out] pSrc points to in-place buffer of unknown 32-bit data type
70 @param[in] bitRevLen bit reversal table length
71 @param[in] pBitRevTab points to bit reversal table
72 @return none
73 */
74
arm_bitreversal_32(uint32_t * pSrc,const uint16_t bitRevLen,const uint16_t * pBitRevTab)75 void arm_bitreversal_32(
76 uint32_t *pSrc,
77 const uint16_t bitRevLen,
78 const uint16_t *pBitRevTab)
79 {
80 uint32_t a, b, i, tmp;
81
82 for (i = 0; i < bitRevLen; )
83 {
84 a = pBitRevTab[i ] >> 2;
85 b = pBitRevTab[i + 1] >> 2;
86
87 //real
88 tmp = pSrc[a];
89 pSrc[a] = pSrc[b];
90 pSrc[b] = tmp;
91
92 //complex
93 tmp = pSrc[a+1];
94 pSrc[a+1] = pSrc[b+1];
95 pSrc[b+1] = tmp;
96
97 i += 2;
98 }
99 }
100
101
102 /**
103 @brief In-place 16 bit reversal function.
104 @param[in,out] pSrc points to in-place buffer of unknown 16-bit data type
105 @param[in] bitRevLen bit reversal table length
106 @param[in] pBitRevTab points to bit reversal table
107 @return none
108 */
109
arm_bitreversal_16(uint16_t * pSrc,const uint16_t bitRevLen,const uint16_t * pBitRevTab)110 void arm_bitreversal_16(
111 uint16_t *pSrc,
112 const uint16_t bitRevLen,
113 const uint16_t *pBitRevTab)
114 {
115 uint16_t a, b, i, tmp;
116
117 for (i = 0; i < bitRevLen; )
118 {
119 a = pBitRevTab[i ] >> 2;
120 b = pBitRevTab[i + 1] >> 2;
121
122 //real
123 tmp = pSrc[a];
124 pSrc[a] = pSrc[b];
125 pSrc[b] = tmp;
126
127 //complex
128 tmp = pSrc[a+1];
129 pSrc[a+1] = pSrc[b+1];
130 pSrc[b+1] = tmp;
131
132 i += 2;
133 }
134 }
135