89 #define timernormalize(_a_) \  argument
90 	if ((_a_)->tv_usec >= 1000000) \
92 		(_a_)->tv_sec  += (_a_)->tv_usec / 1000000; \
93 		(_a_)->tv_usec  = (_a_)->tv_usec % 1000000; \
95 	if ((_a_)->tv_usec < 0) \
97 		(_a_)->tv_sec  -= 1 + (-(_a_)->tv_usec / 1000000); \
98 		(_a_)->tv_usec = 999999 - (-(_a_)->tv_usec - 1); \
104 #define timeradd(_a_, _b_) \  argument
105 	(_a_)->tv_sec  += (_b_)->tv_sec; \
106 	(_a_)->tv_usec += (_b_)->tv_usec; \
107 	timernormalize((_a_))
112 #define timersub(_a_, _b_) \  argument
113 	(_a_)->tv_sec  -= (_b_)->tv_sec; \
114 	(_a_)->tv_usec -= (_b_)->tv_usec; \
115 	timernormalize((_a_))