diff --git a/libc/include/sys/time.h b/libc/include/sys/time.h
index 1f010d4..67107c6 100644
--- a/libc/include/sys/time.h
+++ b/libc/include/sys/time.h
@@ -73,6 +73,15 @@
         }                                             \
     } while (0)
 
+#define TIMEVAL_TO_TIMESPEC(tv, ts) {     \
+    (ts)->tv_sec = (tv)->tv_sec;          \
+    (ts)->tv_nsec = (tv)->tv_usec * 1000; \
+}
+#define TIMESPEC_TO_TIMEVAL(tv, ts) {     \
+    (tv)->tv_sec = (ts)->tv_sec;          \
+    (tv)->tv_usec = (ts)->tv_nsec / 1000; \
+}
+
 __END_DECLS
 
 #endif /* _SYS_TIME_H_ */