diff --git a/src/lephisto.c b/src/lephisto.c
index 0e26701..45d5bdd 100644
--- a/src/lephisto.c
+++ b/src/lephisto.c
@@ -262,9 +262,12 @@ static double fps_dt = 1.;
 static double dt = 0.;
 // @brief Controls the FPS.
 static void fps_control(void) {
+  unsigned int t;
+
   // dt in ms/1000.
-  dt = (double)(SDL_GetTicks() - gtime) / 1000.;
-  gtime = SDL_GetTicks();
+  t = SDL_GetTicks();
+  dt = (double)(t-gtime)/1000.;
+  gtime = t;
 
   if(paused) SDL_Delay(10); // Drop paused FPS to be nice to the CPU.