<util/parity.h>: Parity bit generation

Defines
#define	parity_even_bit(val)

---

Detailed Description

 #include <util/parity.h> 

This header file contains optimized assembler code to calculate the parity bit for a byte.

---

Define Documentation

#define parity_even_bit

(

val

)

Value:

(__extension__({                                        \
        unsigned char __t;                              \
        __asm__ (                                       \
                "mov __tmp_reg__,%0" "\n\t"             \
                "swap %0" "\n\t"                        \
                "eor %0,__tmp_reg__" "\n\t"             \
                "mov __tmp_reg__,%0" "\n\t"             \
                "lsr %0" "\n\t"                         \
                "lsr %0" "\n\t"                         \
                "eor %0,__tmp_reg__"                    \
                : "=r" (__t)                            \
                : "0" ((unsigned char)(val))            \
                : "r0"                                  \
        );                                              \
        (((__t + 1) >> 1) & 1);                         \
 }))

Returns:

1 if val has an odd number of bits set.