git.zerfleddert.de Git - proxmark3-svn/blob - common/parity.h

   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 */