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 // 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 */