1/*        $NetBSD: biosmca.S,v 1.4 2003/02/01 14:48:18 dsl Exp $      */
2
3/*
4 * Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
5 *
6 * Mach Operating System
7 * Copyright (c) 1992, 1991 Carnegie Mellon University
8 * All Rights Reserved.
9 *
10 * Permission to use, copy, modify and distribute this software and its
11 * documentation is hereby granted, provided that both the copyright
12 * notice and this permission notice appear in all copies of the
13 * software, derivative works or modified versions, and any portions
14 * thereof, and that both notices appear in supporting documentation.
15 *
16 * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
17 * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
18 * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
19 *
20 * Carnegie Mellon requests users of this software to return to
21 *
22 *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
23 *  School of Computer Science
24 *  Carnegie Mellon University
25 *  Pittsburgh PA 15213-3890
26 *
27 * any improvements or extensions that they make and grant Carnegie Mellon
28 * the rights to redistribute these changes.
29 */
30
31/*
32  Copyright 1988, 1989, 1990, 1991, 1992
33   by Intel Corporation, Santa Clara, California.
34
35                All Rights Reserved
36
37Permission to use, copy, modify, and distribute this software and
38its documentation for any purpose and without fee is hereby
39granted, provided that the above copyright notice appears in all
40copies and that both the copyright notice and this permission notice
41appear in supporting documentation, and that the name of Intel
42not be used in advertising or publicity pertaining to distribution
43of the software without specific, written prior permission.
44
45INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
46INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
47IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
48CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
49LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
50NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
51WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
52*/
53
54/* extracted from netbsd:sys/arch/i386/stand/bios_disk.S */
55
56#include <machine/asm.h>
57
58          .data
59          .globl _C_LABEL(biosmca_ps2model)
60_C_LABEL(biosmca_ps2model):   .long 0
61
62          .text
63/*
64# BIOS call "INT 0x15 Function 0xc0" to read extended sys config info on PS/2
65#         Return:             no return value
66#
67# This function initializes biosmca_ps2model with model number as
68# identified by BIOS, if the machine is a PS/2 box (i.e. has MCA bus
69# instead of ISA).
70*/
71ENTRY(biosmca)
72          .code32
73          pushl     %ebp
74          movl    %esp, %ebp
75          pushl     %ebx
76          push      %ecx
77          push      %edx
78          push      %esi
79          push      %edi
80          push      %eax
81
82          call      _C_LABEL(prot_to_real)        # enter real mode
83          .code16
84
85          # zero %ecx
86          xorl      %ecx, %ecx
87
88          xor       %ax, %ax
89          movb      $0xc0, %ah                    # subfunction
90          int       $0x15
91          jc        back
92
93          # check feature byte 1 if MCA bus present and replaces ISA
94          movb      %es:5(%bx), %al
95          andb      $0x02, %al          # bit 1 set means MCA instead of ISA
96                                        # see also arch/i386/mca/mca_machdep.c
97          jnz       back
98
99          # save model and submodel bytes to %cx
100          movb      %es:2(%bx), %ch               # model (1 byte)
101          movb      %es:3(%bx), %cl               # submodel (1 byte)
102
103back:
104          calll     _C_LABEL(real_to_prot)        # back to protected mode
105          .code32
106
107          # save model
108          movl      %ecx, _C_LABEL(biosmca_ps2model)
109
110          pop       %eax
111          pop       %edi
112          pop       %esi
113          pop       %edx
114          pop       %ecx
115          popl      %ebx
116          popl      %ebp
117          ret
118