[unix-history] / usr / src / sys / vax / clock.c

/*	clock.c	6.1	83/07/29	*/

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

#include "../vax/mtpr.h"
#include "../vax/clock.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()
{

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

/*
 * 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 provides the rest.
 */
inittodr(base)
	time_t base;
{
	register u_int todr = mfpr(TODR);
	long deltat;
	int year = YRREF;

	if (base < 5*SECYR) {
		printf("WARNING: preposterous time in file system");
		time.tv_sec = 6*SECYR + 186*SECDAY + SECDAY/2;
		resettodr();
		goto check;
	}
	/*
	 * TODRZERO is base used by VMS, which runs on local time.
	 */
	if (todr < TODRZERO) {
		printf("WARNING: todr too small");
		time.tv_sec = base;
		/*
		 * Believe the time in the file system for lack of
		 * anything better, resetting the TODR.
		 */
		resettodr();
		goto check;
	}

	/*
	 * Sneak to within 6 month 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;
	while (time.tv_sec < base-SECYR/2) {
		if (LEAPYEAR(year))
			time.tv_sec += SECDAY;
		year++;
		time.tv_sec += SECYR;
	}

	/*
	 * 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);
check:
	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()
{
	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);
}
Commit	Line	Data
61c578c4 C	1	/* clock.c 6.1 83/07/29 */
	2
	3	#include "../h/param.h"
	4	#include "../h/time.h"
	5	#include "../h/kernel.h"
	6
	7	#include "../vax/mtpr.h"
	8	#include "../vax/clock.h"
	9
	10	/*
	11	* Machine-dependent clock routines.
	12	*
	13	* Startrtclock restarts the real-time clock, which provides
	14	* hardclock interrupts to kern_clock.c.
	15	*
	16	* Inittodr initializes the time of day hardware which provides
	17	* date functions. Its primary function is to use some file
	18	* system information in case the hardare clock lost state.
	19	*
	20	* Resettodr restores the time of day hardware after a time change.
	21	*/
	22
	23	/*
	24	* Start the real-time clock.
	25	*/
	26	startrtclock()
	27	{
	28
	29	mtpr(NICR, -1000000/hz);
	30	mtpr(ICCS, ICCS_RUN+ICCS_IE+ICCS_TRANS+ICCS_INT+ICCS_ERR);
	31	}
	32
	33	/*
	34	* Initialze the time of day register, based on the time base which is, e.g.
	35	* from a filesystem. Base provides the time to within six months,
	36	* and the time of year clock provides the rest.
	37	*/
	38	inittodr(base)
	39	time_t base;
	40	{
	41	register u_int todr = mfpr(TODR);
	42	long deltat;
	43	int year = YRREF;
	44
	45	if (base < 5*SECYR) {
	46	printf("WARNING: preposterous time in file system");
	47	time.tv_sec = 6SECYR + 186SECDAY + SECDAY/2;
	48	resettodr();
	49	goto check;
	50	}
	51	/*
	52	* TODRZERO is base used by VMS, which runs on local time.
	53	*/
	54	if (todr < TODRZERO) {
	55	printf("WARNING: todr too small");
	56	time.tv_sec = base;
	57	/*
	58	* Believe the time in the file system for lack of
	59	* anything better, resetting the TODR.
	60	*/
	61	resettodr();
	62	goto check;
	63	}
	64
65	/*
66	* Sneak to within 6 month of the time in the filesystem,
67	* by starting with the time of the year suggested by the TODR,
68	* and advancing through succesive years. Adding the number of
69	* seconds in the current year takes us to the end of the current year
70	* and then around into the next year to the same position.
71	*/
72	time.tv_sec = (todr-TODRZERO)/100;
73	while (time.tv_sec < base-SECYR/2) {
74	if (LEAPYEAR(year))
75	time.tv_sec += SECDAY;
76	year++;
77	time.tv_sec += SECYR;
78	}
79
80	/*
81	* See if we gained/lost two or more days;
82	* if so, assume something is amiss.
83	*/
84	deltat = time.tv_sec - base;
85	if (deltat < 0)
86	deltat = -deltat;
87	if (deltat < 2*SECDAY)
88	return;
89	printf("WARNING: clock %s %d days",
90	time.tv_sec < base ? "lost" : "gained", deltat / SECDAY);
91	check:
92	printf(" -- CHECK AND RESET THE DATE!\n");
93	}
94
95	/*
96	* Reset the TODR based on the time value; used when the TODR
97	* has a preposterous value and also when the time is reset
98	* by the stime system call. Also called when the TODR goes past
99	* TODRZERO + 100(SECYEAR+2SECDAY) (e.g. on Jan 2 just after midnight)
100	* to wrap the TODR around.
101	*/
102	resettodr()
103	{
104	int year = YRREF;
105	u_int secyr;
106	u_int yrtime = time.tv_sec;
107
108	/*
109	* Whittle the time down to an offset in the current year,
110	* by subtracting off whole years as long as possible.
111	*/
112	for (;;) {
113	secyr = SECYR;
114	if (LEAPYEAR(year))
115	secyr += SECDAY;
116	if (yrtime < secyr)
117	break;
118	yrtime -= secyr;
119	year++;
120	}
121	mtpr(TODR, TODRZERO + yrtime*100);
122	}