xref: /netbsd/sys/arch/i386/stand/lib/biosvideomode.S (revision bf9ec67e)
1
2/*
3 * Copyright (c) 1996
4 * 	Perry E. Metzger.  All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 *    must display the following acknowledgements:
16 *	This product includes software developed for the NetBSD Project
17 *	by Perry E. Metzger.
18 * 4. The names of the authors may not be used to endorse or promote products
19 *    derived from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 *
32 */
33
34
35#include <machine/asm.h>
36
37#define	data32	.byte 0x66
38
39	.text
40
41ENTRY(biosvideomode)
42	pushl	%ebp
43	movl	%esp,%ebp
44	pushl	%ebx
45	push	%esi
46	push	%edi
47
48	call	_C_LABEL(prot_to_real)
49
50	movb	$0, %ah
51	movb	$2, %al
52	int	$0x10
53	# zero-extend 16-bit result to 32 bits.
54	data32
55	movl	$0, %ebx
56	mov	%eax,%ebx		# !!! at run time, it is mov %ax,%bx
57
58	data32
59	call	_C_LABEL(real_to_prot)
60
61	movl	%ebx, %eax
62
63	pop	%edi
64	pop	%esi
65	popl	%ebx
66	popl	%ebp
67	ret
68