time.c

一款类linux的操作系统源码

#include <44b.h>
#include <sys.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/tmr.h>
#include <sys/intr.h>
#include <sys/time.h>
#include <sys/queue.h>
#include <sys/timer.h>
#include <sys/config.h>

#define EPOCH_YEAR	1970

/* Duration added to current time of day for each timer interrupt */
u_long tick = 1000000 * (128/CLOCK) / 128; 

static struct timeval systemclock = { 0, 0 };
static int timerclock = 0;

static void
clock_isr(void *params)
{
#if _TIME_SLICING
    proc_t proc;
    int preempt = 0;
#endif

    disable;

    // Increment system time 
    systemclock.tv_usec += tick;
    timernormalize(&systemclock);

    // Increment timer clock 
    timerclock += tick;
    if (timerclock >= TIMER_ISR_PERIOD) {
	timer_isr();
	timerclock = 0;
    #if _TIME_SLICING
	preempt = 1;
    #endif
    }

    // Issue timer  eoi 
    intr_eoi(INTR_TICK);

#if _TIME_SLICING
    if (preempt) {
	proc = firstq(&ready);
	if (proc != NULL) {
	    current->state = PS_READY;
	    insq(current, &ready);
	    proc_transfer();	       // enables interrupts 
	} else
	    enable;
    }
#else
    enable;
#endif

    
//    #define _TEST 1
//
//    if(_TEST)
//    {
//       unsigned char test_sec = 0;
//   
//       rRTCCON = 0x01;
//       if(test_sec !=  rBCDSEC)
//       {
//          test_sec = rBCDSEC;
//          kprintf( "%02x, %02x, %02x, %02x, %02x, %02x, ",
//                rBCDYEAR,rBCDMON,rBCDDAY,rBCDHOUR,rBCDMIN,rBCDSEC);
//          kprintf("\b\b\b\b\b\b\b\b\b\b\b\b");
//          kprintf("\b\b\b\b\b\b\b\b\b\b\b\b");
//       }
//       rRTCCON = 0x00;
//    }

}



void  
rtc_init()
{
    rRTCCON = 0x01;	// R/W enable, 1/32768, Normal(merge), No reset

    rBCDYEAR = 0x02;
    rBCDMON  = 0x01;
    rBCDDAY  = 0x01;	// SUN:1 MON:2 TUE:3 WED:4 THU:5 FRI:6 SAT:7
    rBCDDATE = 0x03;
    rBCDHOUR = 0x00;
    rBCDMIN  = 0x00;
    rBCDSEC  = 0x00;

    rRTCCON = 0x00;	// R/W enable, 1/32768, Normal(merge), No reset
}

void
time_init()
{
    char buf[sizeof(struct tm)];
    struct tm *tm;

    isr_inst(INTR_TICK, clock_isr, NULL);

    /* A tmr frequency of zero causes the default CLOCK to be used */
    tmrstart();

    intr_unmask(INTR_TICK);

    tm = (struct tm *) buf;

    rRTCCON = 0x01;
    tm->tm_year = bcd2int(rBCDYEAR);
    tm->tm_mon  = bcd2int(rBCDMON) - 1;
    tm->tm_mday = bcd2int(rBCDDAY);
    tm->tm_hour = bcd2int(rBCDHOUR);
    tm->tm_min  = bcd2int(rBCDMIN);
    tm->tm_sec  = bcd2int(rBCDSEC);

    if(tm->tm_sec == 0)
    {
       tm->tm_year = bcd2int(rBCDYEAR);
       tm->tm_mon  = bcd2int(rBCDMON) - 1;
       tm->tm_mday = bcd2int(rBCDDAY);
       tm->tm_hour = bcd2int(rBCDHOUR);
       tm->tm_min  = bcd2int(rBCDMIN);
       tm->tm_sec  = bcd2int(rBCDSEC);
    }
    rRTCCON = 0x00;

    /* Y2K */
    if (tm->tm_year < EPOCH_YEAR % 100)
	tm->tm_year += 100;

    tm->tm_wday = 0;
    tm->tm_yday = 0;
    tm->tm_isdst = 0;

    systemclock.tv_sec = tm2time(tm);
}


time_t
time()
{
    return systemclock.tv_sec;
}

/*
 * The caller must disable/enable interrupts
 */
void
utime(long *tv_sec, long *tv_usec)
{
    *tv_sec = systemclock.tv_sec;
    *tv_usec = systemclock.tv_usec;
}