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Defines | |
#define | parity_even_bit(val) |
#include <util/parity.h>
This header file contains optimized assembler code to calculate the parity bit for a byte.
#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); \ }))
val
has an odd number of bits set.