xref: /openbsd/sys/arch/i386/stand/libsa/ps2probe.c (revision 404b540a)
1 /*	$OpenBSD: ps2probe.c,v 1.1 2004/03/19 13:48:18 tom Exp $	*/
2 
3 /*
4  * Copyright (c) 2001 Michael Shalayeff
5  * 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 OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
20  * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
21  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
22  * SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
24  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
25  * IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
26  * THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include "libsa.h"
30 
31 int ps2model;
32 
33 void
34 ps2probe(void)
35 {
36 	char *p;
37 	int r;
38 
39 	__asm __volatile(DOINT(0x15) "\n\t"
40 			 "setc %b0\n\t"
41 			 : "=a" (r), "=b" (p)
42 			 : "0" (0xc000)
43 			 : "%ecx", "cc");
44 	if (!(r & 0xff))
45 		ps2model = (p[2] << 8) | p[3];
46 }
47