parity.h

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#ifndef PARITY_H
#define PARITY_H

namespace fun
{

    /* Determine parity of argument: 1 = odd, 0 = even */
    #ifdef __i386__
    static inline int parityb(unsigned char x){
      __asm__ __volatile__ ("test %1,%1;setpo %0" : "=g"(x) : "r" (x));
      return x;
    }
    #else

    #if __cplusplus
    extern "C" {
    #endif
    void partab_init();
    #if __cplusplus
    };
    #endif

    static inline int parityb(unsigned char x){
      extern unsigned char Partab[256];
      extern int Parity_initialized;
      if(!Parity_initialized){
        partab_init();
      }
      return Partab[x];
    }
    #endif

    static inline int parity(int x){
      /* Fold down to one byte */
      x ^= (x >> 16);
      x ^= (x >> 8);
      return parityb(x);
    }
}


#endif // PARITY_H