drivers/gp2x/throttle.c

   1 #include <sys/time.h>
   2 #include "main.h"
   3 #include "throttle.h"
   4
   5 #if 0
   6 static uint64 tfreq;
   7 static uint64 desiredfps;
   8
   9 void RefreshThrottleFPS(void)
  10 {
  11  uint64 f=FCEUI_GetDesiredFPS();
  12  // great, a bit faster than before
  13  //f = (f*65) >> 6;
  14  desiredfps=f>>8;
  15  tfreq=1000000;
  16  tfreq<<=16;    /* Adjustment for fps returned from FCEUI_GetDesiredFPS(). */
  17 }
  18
  19 static uint64 GetCurTime(void)
  20 {
  21  uint64 ret;
  22  struct timeval tv;
  23
  24  gettimeofday(&tv,0);
  25  ret=(uint64)tv.tv_sec*1000000;
  26  ret+=tv.tv_usec;
  27  return(ret);
  28 }
  29
  30 INLINE void SpeedThrottle(void)
  31 {
  32  static uint64 ttime,ltime;
  33
  34  waiter:
  35
  36  ttime=GetCurTime();
  37
  38  if( (ttime-ltime) < (tfreq/desiredfps) )
  39  {
  40   goto waiter;
  41  }
  42  if( (ttime-ltime) >= (tfreq*4/desiredfps))
  43   ltime=ttime;
  44  else
  45   ltime+=tfreq/desiredfps;
  46 }
  47
  48 #else
  49
  50 extern uint8 PAL;
  51 extern int FSkip, FSkip_setting;
  52 static int usec_aim = 0, usec_done = 0;
  53 static int skip_count = 0;
  54
  55 INLINE void SpeedThrottle(void)
  56 {
  57         static struct timeval tv_prev;
  58         struct timeval tv_now;
  59         int delta_nom = PAL ? 19997 : 16639; // ~50.007, 19.997 ms/frame : ~60.1, 16.639 ms/frame
  60
  61
  62         if (usec_done == 0) { // first time
  63                 usec_done = 1;
  64                 gettimeofday(&tv_prev, 0);
  65                 return;
  66         }
  67
  68         gettimeofday(&tv_now, 0);
  69
  70         usec_aim += delta_nom;
  71         if (tv_now.tv_sec != tv_prev.tv_sec)
  72                 usec_done += 1000000;
  73         usec_done += tv_now.tv_usec - tv_prev.tv_usec;
  74
  75 #ifdef FRAMESKIP
  76         if (FSkip_setting >= 0)
  77         {
  78                 if (skip_count >= FSkip_setting)
  79                         skip_count = 0;
  80                 else {
  81                         skip_count++;
  82                         FSkip = 1;
  83                 }
  84         }
  85         else if (usec_done > usec_aim + 1024*4)
  86         {
  87                 /* auto frameskip */
  88                 if (usec_done - usec_aim > 150000)
  89                         usec_done = usec_aim = 1; // too much behind, try to recover..
  90                 FSkip = 1;
  91                 tv_prev = tv_now;
  92                 return;
  93         }
  94 #endif
  95
  96         tv_prev = tv_now;
  97         while (usec_done < usec_aim)
  98         {
  99                 gettimeofday(&tv_now, 0);
 100
 101                 if (tv_now.tv_sec != tv_prev.tv_sec)
 102                         usec_done += 1000000;
 103                 usec_done += tv_now.tv_usec - tv_prev.tv_usec;
 104                 tv_prev = tv_now;
 105         }
 106         usec_done = usec_done - usec_aim + 1; // reset to prevent overflows
 107         usec_aim = 0;
 108 }
 109 #endif
 110