xref: /netbsd/sys/arch/i386/stand/lib/biosgetrtc.S (revision 6550d01e)
1/*	$NetBSD: biosgetrtc.S,v 1.6 2005/12/11 12:17:48 christos Exp $	*/
2
3/*
4 * Copyright (c) 1996
5 *	Matthias Drochner.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26 *
27 */
28
29#include <machine/asm.h>
30
31ENTRY(biosgetrtc)
32	pushl	%ebp
33	movl	%esp, %ebp
34	pushl	%ebx
35	pushl	%ecx
36	pushl	%edx
37	push	%esi
38	push	%edi
39
40	xorl	%ebx, %ebx
41
42	call	_C_LABEL(prot_to_real)	# enter real mode
43	.code16
44
45	movb	$2, %ah
46	int	$0x1a
47	jnc	ok
48	movl	$-1, %ebx
49
50ok:
51	calll	_C_LABEL(real_to_prot) # back to protected mode
52	.code32
53
54	movl	8(%ebp), %eax
55	movl	$0, (%eax)
56	movb	%ch, (%eax)
57	movb	%cl, 1(%eax)
58	movb	%dh, 2(%eax)
59
60	movl	%ebx, %eax
61
62	pop	%edi
63	pop	%esi
64	popl	%edx
65	popl	%ecx
66	popl	%ebx
67	popl	%ebp
68	ret
69