#define	Timercmp(tvp, uvp, cmp)						\
	(((tvp)->tv_sec == (uvp)->tv_sec) ?				\
	    ((tvp)->tv_usec cmp (uvp)->tv_usec) :			\
	    ((tvp)->tv_sec cmp (uvp)->tv_sec))
#define	Timeradd(tvp, uvp, vvp)						\
	do {								\
		(vvp)->tv_sec = (tvp)->tv_sec + (uvp)->tv_sec;		\
		(vvp)->tv_usec = (tvp)->tv_usec + (uvp)->tv_usec;	\
		if ((vvp)->tv_usec >= 1000000) {			\
			(vvp)->tv_sec++;				\
			(vvp)->tv_usec -= 1000000;			\
		}							\
	} while (0)
#define	Timersub(tvp, uvp, vvp)						\
	do {								\
		(vvp)->tv_sec = (tvp)->tv_sec - (uvp)->tv_sec;		\
		(vvp)->tv_usec = (tvp)->tv_usec - (uvp)->tv_usec;	\
		if ((vvp)->tv_usec < 0) {				\
			(vvp)->tv_sec--;				\
			(vvp)->tv_usec += 1000000;			\
		}							\
	} while (0)