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[unix-history] / .ref-BSD-4_3_Tahoe / usr / src / sys / vax / clock.c

/*
* Copyright (c) 1982, 1986, 1988 Regents of the University of California.
* All rights reserved.  The Berkeley software License Agreement
* specifies the terms and conditions for redistribution.
*
*      @(#)clock.c     7.3 (Berkeley) 7/9/88
*/

#include "param.h"
#include "time.h"
#include "kernel.h"

#include "mtpr.h"
#include "clock.h"
#include "cpu.h"

/*
* Machine-dependent clock routines.
*
* Startrtclock restarts the real-time clock, which provides
* hardclock interrupts to kern_clock.c.
*
* Inittodr initializes the time of day hardware which provides
* date functions.  Its primary function is to use some file
* system information in case the hardare clock lost state.
*
* Resettodr restores the time of day hardware after a time change.
*/

/*
* Start the real-time clock.
*/
startrtclock()
{

       (*cpuops->cpu_clock->clkstartrt)();
}

/*
* Initialze the time of day register, based on the time base which is, e.g.
* from a filesystem.  Base provides the time to within six months,
* and the time of year clock (if any) provides the rest.
*/
inittodr(base)
       time_t base;
{
       long deltat, badbase = 0;

       if (base < 5*SECYR) {
               printf("WARNING: preposterous time in file system\n");
               /* read the system clock anyway */
               base = 6*SECYR + 186*SECDAY + SECDAY/2;
               badbase = 1;
       }
       switch ((*cpuops->cpu_clock->clkread)(base)) {

       case CLKREAD_BAD:
               /*
                * Believe the time in the file system for lack of
                * anything better, resetting the TODR.
                */
               time.tv_sec = base;
               if (!badbase)
                       resettodr();
               break;

       case CLKREAD_WARN:
               break;

       case CLKREAD_OK:
               if (badbase)
                       break;
               /*
                * See if we gained/lost two or more days;
                * if so, assume something is amiss.
                */
               deltat = time.tv_sec - base;
               if (deltat < 0)
                       deltat = -deltat;
               if (deltat < 2 * SECDAY)
                       return;
               printf("WARNING: clock %s %d days",
                   time.tv_sec < base ? "lost" : "gained", deltat / SECDAY);
               break;

       default:
               panic("inittodr");
               /* NOTREACHED */
       }
       printf(" -- CHECK AND RESET THE DATE!\n");
}

/*
* Reset the TODR based on the time value; used when the TODR
* has a preposterous value and also when the time is reset
* by the stime system call.  Also called when the TODR goes past
* TODRZERO + 100*(SECYEAR+2*SECDAY) (e.g. on Jan 2 just after midnight)
* to wrap the TODR around.
*/
resettodr()
{

       (*cpuops->cpu_clock->clkwrite)();
}

/*
* ``Standard'' VAX clock routines.
*/
#if VAX8600 || VAX8200 || VAX780 || VAX750 || VAX730
vaxstd_clkstartrt()
{

       mtpr(NICR, -1000000/hz);
       mtpr(ICCS, ICCS_RUN+ICCS_IE+ICCS_TRANS+ICCS_INT+ICCS_ERR);
}
#endif

#if VAX8600 || VAX780 || VAX750 || VAX730
vaxstd_clkread(base)
       time_t base;
{
       register u_int todr = mfpr(TODR);
       int year;

       /*
        * TODRZERO is base used by VMS, which runs on local time.
        */
       if (todr < TODRZERO) {
               printf("WARNING: todr too small");
               return (CLKREAD_BAD);
       }

       /*
        * Sneak to within 6 months of the time in the filesystem,
        * by starting with the time of the year suggested by the TODR,
        * and advancing through succesive years.  Adding the number of
        * seconds in the current year takes us to the end of the current year
        * and then around into the next year to the same position.
        */
       time.tv_sec = (todr - TODRZERO) / 100;
       year = YRREF;
       while (time.tv_sec < base - SECYR/2) {
               if (LEAPYEAR(year))
                       time.tv_sec += SECDAY;
               year++;
               time.tv_sec += SECYR;
       }

       return (CLKREAD_OK);
}

vaxstd_clkwrite()
{
       int year = YRREF;
       u_int secyr;
       u_int yrtime = time.tv_sec;

       /*
        * Whittle the time down to an offset in the current year,
        * by subtracting off whole years as long as possible.
        */
       for (;;) {
               secyr = SECYR;
               if (LEAPYEAR(year))
                       secyr += SECDAY;
               if (yrtime < secyr)
                       break;
               yrtime -= secyr;
               year++;
       }
       mtpr(TODR, TODRZERO + yrtime*100);
}
#endif

#if VAX8200 || VAX630
/*
* This code is defunct after 2099.
* Will Unix still be here then??
*/
short dayyr[12] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };

chiptotime(c)
       register struct chiptime *c;
{
       register int days, yr;

       /* simple sanity checks */
       if (c->year < 70 || c->mon < 1 || c->mon > 12 ||
           c->day < 1 || c->day > 31) {
               printf("WARNING: preposterous clock chip time");
               return (0);
       }
       days = 0;
       for (yr = 70; yr < c->year; yr++)
               days += LEAPYEAR(yr) ? 366 : 365;
       days += dayyr[c->mon - 1] + c->day - 1;
       if (LEAPYEAR(yr) && c->mon > 2)
               days++;
       /* now have days since Jan 1, 1970; the rest is easy... */
       return (days * SECDAY + c->hour * 3600 + c->min * 60 + c->sec);
}

timetochip(c)
       register struct chiptime *c;
{
       register int t, t2, t3;

       /* compute the year */
       t2 = time.tv_sec / SECDAY;
       t = 69;
       while (t2 >= 0) {       /* whittle off years */
               t3 = t2;
               t++;
               t2 -= LEAPYEAR(t) ? 366 : 365;
       }
       c->year = t;

       /* t3 = month + day; separate */
       t = LEAPYEAR(t);
       for (t2 = 1; t2 < 12; t2++)
               if (t3 < dayyr[t2] + (t && t2 > 1))
                       break;

       /* t2 is month */
       c->mon = t2;
       c->day = t3 - dayyr[t2 - 1] + 1;
       if (t && t2 > 2)
               c->day--;

       /* the rest is easy */
       t = time.tv_sec % SECDAY;
       c->hour = t / 3600;
       t %= 3600;
       c->min = t / 60;
       c->sec = t % 60;
}
#endif