drivers/gp2x/throttle.c

   1 #include <sys/time.h>
   2 #include "main.h"
   3 #include "gp2x.h"
   4 #include "throttle.h"
   5
   6 #if 0
   7 static uint64 tfreq;
   8 static uint64 desiredfps;
   9
  10 void RefreshThrottleFPS(void)
  11 {
  12  uint64 f=FCEUI_GetDesiredFPS();
  13  // great, a bit faster than before
  14  //f = (f*65) >> 6;
  15  desiredfps=f>>8;
  16  tfreq=1000000;
  17  tfreq<<=16;    /* Adjustment for fps returned from FCEUI_GetDesiredFPS(). */
  18 }
  19
  20 static uint64 GetCurTime(void)
  21 {
  22  uint64 ret;
  23  struct timeval tv;
  24
  25  gettimeofday(&tv,0);
  26  ret=(uint64)tv.tv_sec*1000000;
  27  ret+=tv.tv_usec;
  28  return(ret);
  29 }
  30
  31 INLINE void SpeedThrottle(void)
  32 {
  33  static uint64 ttime,ltime;
  34
  35  waiter:
  36
  37  ttime=GetCurTime();
  38
  39  if( (ttime-ltime) < (tfreq/desiredfps) )
  40  {
  41   goto waiter;
  42  }
  43  if( (ttime-ltime) >= (tfreq*4/desiredfps))
  44   ltime=ttime;
  45  else
  46   ltime+=tfreq/desiredfps;
  47 }
  48
  49 #else
  50
  51 extern uint8 PAL;
  52 extern int FSkip;
  53 static int usec_aim = 0, usec_done = 0;
  54 static int skip_count = 0;
  55
  56 INLINE void SpeedThrottle(void)
  57 {
  58         static struct timeval tv_prev;
  59         struct timeval tv_now;
  60         int delta_nom = PAL ? 19997 : 16639; // ~50.007, 19.997 ms/frame : ~60.1, 16.639 ms/frame
  61
  62
  63         if (usec_done == 0) { // first time
  64                 usec_done = 1;
  65                 gettimeofday(&tv_prev, 0);
  66                 return;
  67         }
  68
  69         gettimeofday(&tv_now, 0);
  70
  71         usec_aim += delta_nom;
  72         if (tv_now.tv_sec != tv_prev.tv_sec)
  73                 usec_done += 1000000;
  74         usec_done += tv_now.tv_usec - tv_prev.tv_usec;
  75
  76 #ifdef FRAMESKIP
  77         if (Settings.frameskip >= 0)
  78         {
  79                 if (skip_count >= Settings.frameskip)
  80                         skip_count = 0;
  81                 else {
  82                         skip_count++;
  83                         FSkip = 1;
  84                 }
  85         }
  86         else if (usec_done > usec_aim + 1024*4)
  87         {
  88                 /* auto frameskip */
  89                 if (usec_done - usec_aim > 1024*32)
  90                         usec_done = usec_aim = 1; // too much behind, try to recover..
  91                 else
  92                         FSkip = 1;
  93                 tv_prev = tv_now;
  94                 return;
  95         }
  96 #endif
  97
  98         tv_prev = tv_now;
  99         while (usec_done < usec_aim)
 100         {
 101                 gettimeofday(&tv_now, 0);
 102
 103                 if (tv_now.tv_sec != tv_prev.tv_sec)
 104                         usec_done += 1000000;
 105                 usec_done += tv_now.tv_usec - tv_prev.tv_usec;
 106                 tv_prev = tv_now;
 107         }
 108         usec_done = usec_done - usec_aim + 1; // reset to prevent overflows
 109         usec_aim = 0;
 110 }
 111 #endif
 112