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 = 6*SECYR + 186*SECDAY + 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+2*SECDAY) (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 | } |