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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 | // Generic CRC calculation code. | |
7 | //----------------------------------------------------------------------------- | |
8 | ||
9 | #ifndef __PARITY_H | |
10 | #define __PARITY_H | |
11 | ||
12 | #include <stdint.h> | |
13 | ||
14 | extern const uint8_t OddByteParity[256]; | |
15 | ||
16 | #define oddparity8(x) (OddByteParity[(x)]) | |
17 | ||
18 | ||
19 | extern const uint8_t EvenByteParity[256]; | |
20 | ||
21 | static inline bool /*__attribute__((always_inline))*/ evenparity8(const uint8_t x) { | |
22 | #if !defined __i386__ || !defined __GNUC__ | |
23 | return EvenByteParity[x]; | |
24 | #else | |
25 | uint8_t y; | |
26 | __asm( "testb $255, %1\n" | |
27 | "setpo %0\n" : "=r"(y) : "r"(x): ); | |
28 | return y; | |
29 | #endif | |
30 | } | |
31 | ||
32 | ||
33 | static inline uint8_t evenparity32(uint32_t x) | |
34 | { | |
35 | x ^= x >> 16; | |
36 | x ^= x >> 8; | |
37 | return EvenByteParity[x & 0xff]; | |
38 | } | |
39 | ||
40 | ||
41 | #endif /* __PARITY_H */ |