1/*-
2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD$");
29
30#include <stand.h>
31#include <btxv86.h>
32#include <machine/cpufunc.h>
33#include "bootstrap.h"
34#include "libi386.h"
35
36static int	bios_seconds(void);
37
38/*
39 * Return the BIOS time-of-day value.
40 *
41 * XXX uses undocumented BCD support from libstand.
42 */
43static int
44bios_seconds(void)
45{
46    int			hr, minute, sec;
47    unsigned char	bios_time[6];
48
49    v86.ctl = 0;
50    v86.addr = 0x1c;		/* int 0x1c, function 0 */
51    v86.eax = 0x0000;
52    v86.es  = VTOPSEG(bios_time);
53    v86.ebx = VTOPOFF(bios_time);
54    v86int();
55
56    hr = bcd2bin(bios_time[3]);
57    minute = bcd2bin(bios_time[4]);
58    sec = bcd2bin(bios_time[5]);
59
60    return (hr * 3600 + minute * 60 + sec);
61}
62
63/*
64 * Return the time in seconds since the beginning of the day.
65 */
66time_t
67time(time_t *t)
68{
69    static time_t lasttime;
70    time_t now;
71
72    now = bios_seconds();
73
74    if (now < lasttime)
75	now += 24 * 3600;
76    lasttime = now;
77
78    if (t != NULL)
79	*t = now;
80    return(now);
81}
82
83/*
84 * Use the BIOS Wait function to pause for (period) microseconds.
85 *
86 * Resolution of this function is variable, but typically around
87 * 1ms.
88 */
89void
90delay(int period)
91{
92    int i;
93
94    period = (period + 500) / 1000;
95    for( ; period != 0 ; period--)
96	for(i=800;i != 0; i--)
97	    outb(0x5f,0);       /* wait 600ns */
98}
99