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1f065e1d | 1 | //----------------------------------------------------------------------------- |
2 | // This code is licensed to you under the terms of the GNU GPL, version 2 or, | |
3 | // at your option, any later version. See the LICENSE.txt file for the text of | |
4 | // the license. | |
5 | //----------------------------------------------------------------------------- | |
6 | // Parity functions | |
7 | //----------------------------------------------------------------------------- | |
8 | ||
9 | // all functions defined in header file by purpose. Allows compiler optimizations. | |
10 | ||
11 | #ifndef __PARITY_H | |
12 | #define __PARITY_H | |
13 | ||
14 | #include <stdint.h> | |
15 | #include <stdbool.h> | |
16 | ||
17 | extern const uint8_t OddByteParity[256]; | |
18 | ||
19 | ||
20 | static inline bool oddparity8(const uint8_t x) { | |
21 | return OddByteParity[x]; | |
22 | } | |
23 | ||
24 | ||
25 | static inline bool evenparity8(const uint8_t x) { | |
26 | return !OddByteParity[x]; | |
27 | } | |
28 | ||
29 | ||
30 | static inline bool evenparity32(uint32_t x) | |
31 | { | |
32 | #if !defined __GNUC__ | |
33 | x ^= x >> 16; | |
34 | x ^= x >> 8; | |
35 | return evenparity8(x); | |
36 | #else | |
37 | return __builtin_parity(x); | |
38 | #endif | |
39 | } | |
40 | ||
41 | ||
42 | static inline bool oddparity32(uint32_t x) | |
43 | { | |
44 | #if !defined __GNUC__ | |
45 | x ^= x >> 16; | |
46 | x ^= x >> 8; | |
47 | return oddparity8(x); | |
48 | #else | |
49 | return !__builtin_parity(x); | |
50 | #endif | |
51 | } | |
52 | ||
53 | #endif /* __PARITY_H */ |