heartbeat.c

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00001 
00011 #include <includes.h>
00012 
00013 #define DEFAULT_HEARTBEAT_PERIOD (9) //in units of schedule periods (usually 1 ms)
00014 
00015 static int hb_state = 0; 
00016 static int hb_period = DEFAULT_HEARTBEAT_PERIOD; 
00017 static VOID_VOID_F hb_function = voidvoid; 
00018 static INT_VOID_F hb_get_timestamp = intvoid; 
00028 void hb_init(int period, VOID_VOID_F func, INT_VOID_F get_time){
00029   hb_period = period;
00030   hb_function = func;
00031   hb_get_timestamp = get_time;
00032 }
00033 
00039 static void hb_update(int count){
00040   int new_state = count & (1 << (hb_period - 1));
00041   if (!hb_state && new_state){
00042     hb_function();
00043   } 
00044   hb_state = new_state;
00045 }
00046 
00050 void hb_beat(void){
00051   hb_update(hb_get_timestamp());
00052 }
00053 
00060 int hb_get_count(void){
00061   static int hb_prescale = -1;
00062   static unsigned int hb_count = 0;
00063   hb_prescale++;
00064   if (hb_prescale >= SCHED_SPEED){
00065     hb_count++;
00066     hb_prescale = 0;
00067   }
00068   return hb_count;
00069 }