Merge pull request #722 from fjtrujy/fix_timer_acurracy

Fix timer accuracy

Author: rickgaiser

ee/kernel/src/timer.c

@@ -263,9 +263,10 @@ __attribute__((weak)) s32 StopTimerSystemTime(void)
 #endif
 
 #ifdef F_SetNextComp
+#define CLOCKS_GAP 0x200 // For assuring the timer interrupt is triggered
 void SetNextComp(u64 time_now)
 {
-    u64 a0, a1;
+    u64 current_schedule, next_schedule;
     counter_struct_t *timer_current;
 
     if (g_Timer.current_handling_timer_id >= 0)
@@ -279,30 +280,32 @@ void SetNextComp(u64 time_now)
         SetT2_MODE((*T2_MODE) & (~(1 << 11)));
         return;
     }
-    a0 = timer_current->timer_schedule + timer_current->timer_base_time - timer_current->timer_base_count;
+    current_schedule = timer_current->timer_schedule + timer_current->timer_base_time - timer_current->timer_base_count;
     timer_current = timer_current->timer_next;
+    
+    // Grouping the timers that are so close to each other, to reduce the number of interrupts
     while (timer_current != NULL)
     {
-        a1 = timer_current->timer_schedule + timer_current->timer_base_time - timer_current->timer_base_count;
-        if (a1 < (a0 + 0x733))
+        next_schedule = timer_current->timer_schedule + timer_current->timer_base_time - timer_current->timer_base_count;
+        if (next_schedule < (current_schedule + CLOCKS_GAP))
         {
-            a0 = a1;
+            current_schedule = next_schedule;
         }
         else
         {
             break;
         }
         timer_current = timer_current->timer_next;
     }
-    if (a0 < (time_now + 0x733))
+    if (current_schedule < (time_now + CLOCKS_GAP))
     {
-        SetT2_COMP((*T2_COUNT) + (0x733 >> (((*T2_MODE) & 3) << 2)));
+        SetT2_COMP((*T2_COUNT) + (CLOCKS_GAP >> (((*T2_MODE) & 3) << 2)));
         SetT2_MODE((*T2_MODE) & (~(1 << 11)));
     }
     else
     {
         SetT2_MODE((*T2_MODE) & (~(1 << 11)));
-        SetT2_COMP(a0 >> (((*T2_MODE) & 3) << 2));
+        SetT2_COMP(current_schedule >> (((*T2_MODE) & 3) << 2));
     }
 }
 #endif

ee/libcglue/samples/nanosleep/main.c

@@ -36,7 +36,7 @@ int main(int argc, char *argv[])
     struct timespec tv = {0};
     tv.tv_sec = 1;
     tv.tv_nsec = 0;
-    error_tolerance = 200; // 200 miliseconds of error tolerance
+    error_tolerance = 5; // 5 miliseconds of error tolerance
 
 #if defined(SCREEN_DEBUG)
     init_scr();

ee/libcglue/src/glue.c

@@ -805,7 +805,12 @@ int _gettimeofday(struct timeval *tv, struct timezone *tz)
 #ifdef F__times
 // Called from newlib timesr.c
 clock_t _times(struct tms *buffer) {
-	clock_t clk = GetTimerSystemTime() / (kBUSCLK / (1000 * 1000));
+	clock_t clk;
+	u32 busclock_sec;
+	u32 busclock_usec;
+
+	TimerBusClock2USec(GetTimerSystemTime(), &busclock_sec, &busclock_usec);
+	clk = busclock_sec * CLOCKS_PER_SEC + busclock_usec;
 
 	if (buffer != NULL) {
 		buffer->tms_utime  = clk;

ee/libcglue/src/sleep.c

@@ -43,21 +43,24 @@ int nanosleep(const struct timespec *req, struct timespec *rem)
 	__asm__ __volatile__ ("mfc0\t%0, $12" : "=r" (eie));
 	if ((eie & 0x10000) == 0)
 	{
-		return 0;
+		errno = ENOSYS;  // Functionality not available
+        return -1;
 	}
 	sema.max_count = 1;
 	sema.option = (u32)"nanosleep";
 	sema.init_count = 0;
 	sema_id = CreateSema(&sema);
 	if (sema_id < 0)
 	{
-		return 0;
+		errno = EAGAIN;  // Resource temporarily unavailable
+        return -1;
 	}
 	timer_alarm_id = SetTimerAlarm(Sec2TimerBusClock(req->tv_sec) + NSec2TimerBusClock(req->tv_nsec), nanosleep_wakeup_callback, (void *)sema_id);
 	if (timer_alarm_id < 0)
 	{
 		DeleteSema(sema_id);
-		return 0;
+		errno = EAGAIN;  // Resource temporarily unavailable
+        return -1;
 	}
 	WaitSema(sema_id);
 	DeleteSema(sema_id);