use picofe menu, move generic code out of gp2x/

[fceu.git] / drivers / sdl / throttle.c

diff --git a/drivers/sdl/throttle.c b/drivers/sdl/throttle.c
new file mode 100644 (file)
index 0000000..5272226
--- /dev/null
+++ b/drivers/sdl/throttle.c
@@ -0,0 +1,75 @@
+#include <sys/time.h>
+#include <unistd.h>
+
+#include "../common/main.h"
+#include "../common/throttle.h"
+#include "../common/settings.h"
+
+
+extern uint8 PAL;
+extern int FSkip;
+static int usec_aim = 0, usec_done = 0;
+static int skip_count = 0;
+
+void RefreshThrottleFPS(void)
+{
+       usec_aim = usec_done = skip_count = 0;
+}
+
+void SpeedThrottle(void)
+{
+       static struct timeval tv_prev;
+       struct timeval tv_now;
+       int delta_nom = PAL ? 19997 : 16639; // ~50.007, 19.997 ms/frame : ~60.1, 16.639 ms/frame
+
+
+       if (usec_done == 0) { // first time
+               usec_done = 1;
+               gettimeofday(&tv_prev, 0);
+               return;
+       }
+
+       gettimeofday(&tv_now, 0);
+
+       usec_aim += delta_nom;
+       if (tv_now.tv_sec != tv_prev.tv_sec)
+               usec_done += 1000000;
+       usec_done += tv_now.tv_usec - tv_prev.tv_usec;
+
+#ifdef FRAMESKIP
+       if (Settings.frameskip >= 0)
+       {
+               if (skip_count >= Settings.frameskip)
+                       skip_count = 0;
+               else {
+                       skip_count++;
+                       FSkip = 1;
+               }
+       }
+       else if (usec_done > usec_aim + 1024*4)
+       {
+               /* auto frameskip */
+               if (usec_done - usec_aim > 1024*32)
+                       usec_done = usec_aim = 1; // too much behind, try to recover..
+               else
+                       FSkip = 1;
+               tv_prev = tv_now;
+               return;
+       }
+#endif
+
+       tv_prev = tv_now;
+       while (usec_done < usec_aim)
+       {
+               usleep(300);
+               gettimeofday(&tv_now, 0);
+
+               if (tv_now.tv_sec != tv_prev.tv_sec)
+                       usec_done += 1000000;
+               usec_done += tv_now.tv_usec - tv_prev.tv_usec;
+               tv_prev = tv_now;
+       }
+       usec_done = usec_done - usec_aim + 1; // reset to prevent overflows
+       usec_aim = 0;
+}
+