diff --git a/core/timermanager.h b/core/timermanager.h
index c31568c..465742e 100644
--- a/core/timermanager.h
+++ b/core/timermanager.h
@@ -33,11 +33,11 @@ along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 using namespace std;
 
-#define NS_PER_SEC      1E9
-#define USEC_PER_SEC    1E6
-#define NS_PER_USEC     1000UL
-#define NS_PER_MSEC     1E6
-#define ONE_BILLION_NS  0x3B9ACA00UL
+#define NS_PER_SEC      1000000000
+#define USEC_PER_SEC    1000000
+#define NS_PER_USEC     1000
+#define NS_PER_MSEC     1000000
+#define ONE_BILLION_NS  1000000000
 
 #define USECS_TO_NSECS(us) (us) * NS_PER_USEC
 #define MSECS_TO_NSECS(ms) (ms) * NS_PER_MSEC