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Annotation of 43BSDTahoe/sys/vax/clock.c, revision 1.1

1.1     ! root        1: /*
        !             2:  * Copyright (c) 1982, 1986, 1988 Regents of the University of California.
        !             3:  * All rights reserved.  The Berkeley software License Agreement
        !             4:  * specifies the terms and conditions for redistribution.
        !             5:  *
        !             6:  *     @(#)clock.c     7.3 (Berkeley) 7/9/88
        !             7:  */
        !             8: 
        !             9: #include "param.h"
        !            10: #include "time.h"
        !            11: #include "kernel.h"
        !            12: 
        !            13: #include "mtpr.h"
        !            14: #include "clock.h"
        !            15: #include "cpu.h"
        !            16: 
        !            17: /*
        !            18:  * Machine-dependent clock routines.
        !            19:  *
        !            20:  * Startrtclock restarts the real-time clock, which provides
        !            21:  * hardclock interrupts to kern_clock.c.
        !            22:  *
        !            23:  * Inittodr initializes the time of day hardware which provides
        !            24:  * date functions.  Its primary function is to use some file
        !            25:  * system information in case the hardare clock lost state.
        !            26:  *
        !            27:  * Resettodr restores the time of day hardware after a time change.
        !            28:  */
        !            29: 
        !            30: /*
        !            31:  * Start the real-time clock.
        !            32:  */
        !            33: startrtclock()
        !            34: {
        !            35: 
        !            36:        (*cpuops->cpu_clock->clkstartrt)();
        !            37: }
        !            38: 
        !            39: /*
        !            40:  * Initialze the time of day register, based on the time base which is, e.g.
        !            41:  * from a filesystem.  Base provides the time to within six months,
        !            42:  * and the time of year clock (if any) provides the rest.
        !            43:  */
        !            44: inittodr(base)
        !            45:        time_t base;
        !            46: {
        !            47:        long deltat, badbase = 0;
        !            48: 
        !            49:        if (base < 5*SECYR) {
        !            50:                printf("WARNING: preposterous time in file system\n");
        !            51:                /* read the system clock anyway */
        !            52:                base = 6*SECYR + 186*SECDAY + SECDAY/2;
        !            53:                badbase = 1;
        !            54:        }
        !            55:        switch ((*cpuops->cpu_clock->clkread)(base)) {
        !            56: 
        !            57:        case CLKREAD_BAD:
        !            58:                /*
        !            59:                 * Believe the time in the file system for lack of
        !            60:                 * anything better, resetting the TODR.
        !            61:                 */
        !            62:                time.tv_sec = base;
        !            63:                if (!badbase)
        !            64:                        resettodr();
        !            65:                break;
        !            66: 
        !            67:        case CLKREAD_WARN:
        !            68:                break;
        !            69: 
        !            70:        case CLKREAD_OK:
        !            71:                if (badbase)
        !            72:                        break;
        !            73:                /*
        !            74:                 * See if we gained/lost two or more days;
        !            75:                 * if so, assume something is amiss.
        !            76:                 */
        !            77:                deltat = time.tv_sec - base;
        !            78:                if (deltat < 0)
        !            79:                        deltat = -deltat;
        !            80:                if (deltat < 2 * SECDAY)
        !            81:                        return;
        !            82:                printf("WARNING: clock %s %d days",
        !            83:                    time.tv_sec < base ? "lost" : "gained", deltat / SECDAY);
        !            84:                break;
        !            85: 
        !            86:        default:
        !            87:                panic("inittodr");
        !            88:                /* NOTREACHED */
        !            89:        }
        !            90:        printf(" -- CHECK AND RESET THE DATE!\n");
        !            91: }
        !            92: 
        !            93: /*
        !            94:  * Reset the TODR based on the time value; used when the TODR
        !            95:  * has a preposterous value and also when the time is reset
        !            96:  * by the stime system call.  Also called when the TODR goes past
        !            97:  * TODRZERO + 100*(SECYEAR+2*SECDAY) (e.g. on Jan 2 just after midnight)
        !            98:  * to wrap the TODR around.
        !            99:  */
        !           100: resettodr()
        !           101: {
        !           102: 
        !           103:        (*cpuops->cpu_clock->clkwrite)();
        !           104: }
        !           105: 
        !           106: /*
        !           107:  * ``Standard'' VAX clock routines.
        !           108:  */
        !           109: #if VAX8600 || VAX8200 || VAX780 || VAX750 || VAX730
        !           110: vaxstd_clkstartrt()
        !           111: {
        !           112: 
        !           113:        mtpr(NICR, -1000000/hz);
        !           114:        mtpr(ICCS, ICCS_RUN+ICCS_IE+ICCS_TRANS+ICCS_INT+ICCS_ERR);
        !           115: }
        !           116: #endif
        !           117: 
        !           118: #if VAX8600 || VAX780 || VAX750 || VAX730
        !           119: vaxstd_clkread(base)
        !           120:        time_t base;
        !           121: {
        !           122:        register u_int todr = mfpr(TODR);
        !           123:        int year;
        !           124: 
        !           125:        /*
        !           126:         * TODRZERO is base used by VMS, which runs on local time.
        !           127:         */
        !           128:        if (todr < TODRZERO) {
        !           129:                printf("WARNING: todr too small");
        !           130:                return (CLKREAD_BAD);
        !           131:        }
        !           132: 
        !           133:        /*
        !           134:         * Sneak to within 6 months of the time in the filesystem,
        !           135:         * by starting with the time of the year suggested by the TODR,
        !           136:         * and advancing through succesive years.  Adding the number of
        !           137:         * seconds in the current year takes us to the end of the current year
        !           138:         * and then around into the next year to the same position.
        !           139:         */
        !           140:        time.tv_sec = (todr - TODRZERO) / 100;
        !           141:        year = YRREF;
        !           142:        while (time.tv_sec < base - SECYR/2) {
        !           143:                if (LEAPYEAR(year))
        !           144:                        time.tv_sec += SECDAY;
        !           145:                year++;
        !           146:                time.tv_sec += SECYR;
        !           147:        }
        !           148: 
        !           149:        return (CLKREAD_OK);
        !           150: }
        !           151: 
        !           152: vaxstd_clkwrite()
        !           153: {
        !           154:        int year = YRREF;
        !           155:        u_int secyr;
        !           156:        u_int yrtime = time.tv_sec;
        !           157: 
        !           158:        /*
        !           159:         * Whittle the time down to an offset in the current year,
        !           160:         * by subtracting off whole years as long as possible.
        !           161:         */
        !           162:        for (;;) {
        !           163:                secyr = SECYR;
        !           164:                if (LEAPYEAR(year))
        !           165:                        secyr += SECDAY;
        !           166:                if (yrtime < secyr)
        !           167:                        break;
        !           168:                yrtime -= secyr;
        !           169:                year++;
        !           170:        }
        !           171:        mtpr(TODR, TODRZERO + yrtime*100);
        !           172: }
        !           173: #endif
        !           174: 
        !           175: #if VAX8200 || VAX630
        !           176: /*
        !           177:  * This code is defunct after 2099.
        !           178:  * Will Unix still be here then??
        !           179:  */
        !           180: short dayyr[12] = { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
        !           181: 
        !           182: chiptotime(c)
        !           183:        register struct chiptime *c;
        !           184: {
        !           185:        register int days, yr;
        !           186: 
        !           187:        /* simple sanity checks */
        !           188:        if (c->year < 70 || c->mon < 1 || c->mon > 12 ||
        !           189:            c->day < 1 || c->day > 31) {
        !           190:                printf("WARNING: preposterous clock chip time");
        !           191:                return (0);
        !           192:        }
        !           193:        days = 0;
        !           194:        for (yr = 70; yr < c->year; yr++)
        !           195:                days += LEAPYEAR(yr) ? 366 : 365;
        !           196:        days += dayyr[c->mon - 1] + c->day - 1;
        !           197:        if (LEAPYEAR(yr) && c->mon > 2)
        !           198:                days++;
        !           199:        /* now have days since Jan 1, 1970; the rest is easy... */
        !           200:        return (days * SECDAY + c->hour * 3600 + c->min * 60 + c->sec);
        !           201: }
        !           202: 
        !           203: timetochip(c)
        !           204:        register struct chiptime *c;
        !           205: {
        !           206:        register int t, t2, t3;
        !           207: 
        !           208:        /* compute the year */
        !           209:        t2 = time.tv_sec / SECDAY;
        !           210:        t = 69;
        !           211:        while (t2 >= 0) {       /* whittle off years */
        !           212:                t3 = t2;
        !           213:                t++;
        !           214:                t2 -= LEAPYEAR(t) ? 366 : 365;
        !           215:        }
        !           216:        c->year = t;
        !           217: 
        !           218:        /* t3 = month + day; separate */
        !           219:        t = LEAPYEAR(t);
        !           220:        for (t2 = 1; t2 < 12; t2++)
        !           221:                if (t3 < dayyr[t2] + (t && t2 > 1))
        !           222:                        break;
        !           223: 
        !           224:        /* t2 is month */
        !           225:        c->mon = t2;
        !           226:        c->day = t3 - dayyr[t2 - 1] + 1;
        !           227:        if (t && t2 > 2)
        !           228:                c->day--;
        !           229: 
        !           230:        /* the rest is easy */
        !           231:        t = time.tv_sec % SECDAY;
        !           232:        c->hour = t / 3600;
        !           233:        t %= 3600;
        !           234:        c->min = t / 60;
        !           235:        c->sec = t % 60;
        !           236: }
        !           237: #endif

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