#define sbi(port, bit)				        (port) |= (1 << (bit))
#define cbi(port, bit)				        (port) &= ~(1 << (bit))

#define bit_is_set(var, bit)		    	((var) & (1 << (bit)))
#define bit_is_clear(var, bit)		    	!bit_is_set(var, bit)