xref: /netbsd/sys/arch/i386/stand/lib/biosdelay.S (revision bf9ec67e)
1/*	$NetBSD: biosdelay.S,v 1.1.1.1 1997/03/14 02:40:32 perry Exp $	*/
2
3/*
4 * Copyright (c) 1996, 1997
5 * 	Perry E. Metzger.  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 * 3. All advertising materials mentioning features or use of this software
16 *    must display the following acknowledgements:
17 *	This product includes software developed for the NetBSD Project
18 *	by Perry E. Metzger.
19 * 4. The names of the authors may not be used to endorse or promote products
20 *    derived from this software without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 *
33 */
34
35#include <machine/asm.h>
36
37#define data32	.byte 0x66
38
39	.text
40
41/*
42# BIOS call "INT 15H Function 86H" to sleep for a set number of microseconds
43#	Call with	%ah = 0x86
44#			%cx = time interval (high)
45#			%dx = time interval (low)
46#	Return:
47#		If error
48#			CF  = set
49#		else
50#			CF  = clear
51*/
52ENTRY(delay)
53	pushl	%ebp
54	pushl	%ebx
55	pushl	%esi
56	pushl	%edi
57
58	movw	20(%esp), %dx
59	movw	22(%esp), %cx
60
61	call	_C_LABEL(prot_to_real)
62
63	movb	$0x86, %ah
64	int	$0x15
65	setnc	%ah
66
67	movb	%ah, %bl	# real_to_prot uses %eax
68
69	data32
70	call	_C_LABEL(real_to_prot)
71
72	xorl	%eax, %eax
73	movb	%bl, %al
74
75	popl	%edi
76	popl	%esi
77	popl	%ebx
78	popl	%ebp
79	ret
80