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 */ |