mirror of
https://github.com/JvanKatwijk/qt-dab.git
synced 2025-10-06 00:02:40 +02:00
37 lines
675 B
C
37 lines
675 B
C
|
/**
|
||
|
|
* static inline parity(int x) -- compute parity (up to 32 bits?)
|
||
|
|
*/
|
||
|
|
|
||
|
|
/* 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);
|
||
|
|
}
|