diff --git a/os_functions.c b/os_functions.c
index 7968a09..742cba7 100644
--- a/os_functions.c
+++ b/os_functions.c
@@ -49,8 +49,8 @@ EXPORT_DECL(int, OSSetThreadPriority, void * thread, int priority);
 EXPORT_DECL(int, OSJoinThread, void * thread, int * ret_val);
 EXPORT_DECL(void, OSDetachThread, void * thread);
 EXPORT_DECL(void, OSSleepTicks, u64 ticks);
-EXPORT_DECL(s64, OSGetTick, void);
-EXPORT_DECL(s64, OSGetTime, void);
+EXPORT_DECL(u64, OSGetTick, void);
+EXPORT_DECL(u64, OSGetTime, void);
 EXPORT_DECL(void, OSTicksToCalendarTime, s64 time, OSCalendarTime * calendarTime);