clock.c revision 1.1 
1/*	$NetBSD: clock.c,v 1.1 1995/07/25 23:12:22 chuck Exp $ */
2
3/*
4 * Copyright (c) 1992, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 * Copyright (c) 1994 Gordon W. Ross
7 * Copyright (c) 1993 Adam Glass
8 *
9 * This software was developed by the Computer Systems Engineering group
10 * at Lawrence Berkeley Laboratory under DARPA contract BG 91-66 and
11 * contributed to Berkeley.
12 *
13 * All advertising materials mentioning features or use of this software
14 * must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Lawrence Berkeley Laboratory.
17 *
18 * Redistribution and use in source and binary forms, with or without
19 * modification, are permitted provided that the following conditions
20 * are met:
21 * 1. Redistributions of source code must retain the above copyright
22 *    notice, this list of conditions and the following disclaimer.
23 * 2. Redistributions in binary form must reproduce the above copyright
24 *    notice, this list of conditions and the following disclaimer in the
25 *    documentation and/or other materials provided with the distribution.
26 * 3. All advertising materials mentioning features or use of this software
27 *    must display the following acknowledgement:
28 *	This product includes software developed by the University of
29 *	California, Berkeley and its contributors.
30 * 4. Neither the name of the University nor the names of its contributors
31 *    may be used to endorse or promote products derived from this software
32 *    without specific prior written permission.
33 *
34 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
35 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
36 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
37 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
38 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
39 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
40 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
41 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
42 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
43 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
44 * SUCH DAMAGE.
45 *
46 *	@(#)clock.c	8.1 (Berkeley) 6/11/93
47 */
48
49/*
50 * Clock driver.
51 */
52
53#include <sys/types.h>
54#include "clockreg.h"
55static struct clockreg *clockreg = (struct clockreg *) CLOCK_ADDR;
56
57int hz = 1; /* XXX ? */
58
59/*
60 * BCD to decimal and decimal to BCD.
61 */
62#define	FROMBCD(x)	(((x) >> 4) * 10 + ((x) & 0xf))
63#define	TOBCD(x)	(((x) / 10 * 16) + ((x) % 10))
64
65#define	SECDAY		(24 * 60 * 60)
66#define	SECYR		(SECDAY * 365)
67#define	LEAPYEAR(y)	(((y) & 3) == 0)
68
69/*
70 * This code is defunct after 2068.
71 * Will Unix still be here then??
72 */
73const short dayyr[12] =
74    { 0, 31, 59, 90, 120, 151, 181, 212, 243, 273, 304, 334 };
75
76static u_long chiptotime(sec, min, hour, day, mon, year)
77	register int sec, min, hour, day, mon, year;
78{
79	register int days, yr;
80
81	sec = FROMBCD(sec);
82	min = FROMBCD(min);
83	hour = FROMBCD(hour);
84	day = FROMBCD(day);
85	mon = FROMBCD(mon);
86	year = FROMBCD(year) + YEAR0;
87	if (year < 70) year = 70;
88
89	/* simple sanity checks */
90	if (year < 70 || mon < 1 || mon > 12 || day < 1 || day > 31)
91		return (0);
92	days = 0;
93	for (yr = 70; yr < year; yr++)
94		days += LEAPYEAR(yr) ? 366 : 365;
95	days += dayyr[mon - 1] + day - 1;
96	if (LEAPYEAR(yr) && mon > 2)
97		days++;
98	/* now have days since Jan 1, 1970; the rest is easy... */
99	return (days * SECDAY + hour * 3600 + min * 60 + sec);
100}
101
102/*
103 * Set up the system's time, given a `reasonable' time value.
104 */
105time_t getsecs()
106{
107	register struct clockreg *cl = clockreg;
108	int sec, min, hour, day, mon, year;
109
110	cl->cl_csr |= CLK_READ;		/* enable read (stop time) */
111	sec = cl->cl_sec;
112	min = cl->cl_min;
113	hour = cl->cl_hour;
114	day = cl->cl_mday;
115	mon = cl->cl_month;
116	year = cl->cl_year;
117	cl->cl_csr &= ~CLK_READ;	/* time wears on */
118	return(chiptotime(sec, min, hour, day, mon, year));
119}
120
121/*
122 * delay
123 */
124
125int getticks()
126{
127	return((int)getsecs());
128}
129