X_BIT_CHECK
#define X_BIT_CHECK(var, bit) (((var) &(1U<<(bit)))!=0)
X_BIT_CLEAR
#define X_BIT_CLEAR(var, bit) ((var) &=~(1U<<(bit)))
X_BIT_SET
#define X_BIT_SET(var, bit) ((var)|=(1U<<(bit)))
X_BIT_TOGGLE
#define X_BIT_TOGGLE(var, bit) ((var)^=(1U<<(bit)))