1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
|
/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Obtain memory configuration information from the BIOS
*/
#include <stand.h>
#include "libi386.h"
#include "btxv86.h"
vm_offset_t memtop;
u_int32_t bios_basemem, bios_extmem;
#define SMAPSIG 0x534D4150
struct smap {
u_int64_t base;
u_int64_t length;
u_int32_t type;
} __packed;
static struct smap smap;
void
bios_getmem(void)
{
/* Parse system memory map */
v86.ebx = 0;
do {
v86.ctl = V86_FLAGS;
v86.addr = 0x15; /* int 0x15 function 0xe820*/
v86.eax = 0xe820;
v86.ecx = sizeof(struct smap);
v86.edx = SMAPSIG;
v86.es = VTOPSEG(&smap);
v86.edi = VTOPOFF(&smap);
v86int();
if ((v86.efl & 1) || (v86.eax != SMAPSIG))
break;
/* look for a low-memory segment that's large enough */
if ((smap.type == 1) && (smap.base == 0) && (smap.length >= (512 * 1024)))
bios_basemem = smap.length;
/* look for the first segment in 'extended' memory */
if ((smap.type == 1) && (smap.base == 0x100000)) {
bios_extmem = smap.length;
}
} while (v86.ebx != 0);
/* Fall back to the old compatibility function for base memory */
if (bios_basemem == 0) {
v86.ctl = 0;
v86.addr = 0x12; /* int 0x12 */
v86int();
bios_basemem = (v86.eax & 0xffff) * 1024;
}
/* Fall back through several compatibility functions for extended memory */
if (bios_extmem == 0) {
v86.ctl = V86_FLAGS;
v86.addr = 0x15; /* int 0x15 function 0xe801*/
v86.eax = 0xe801;
v86int();
if (!(v86.efl & 1)) {
bios_extmem = ((v86.ecx & 0xffff) + ((v86.edx & 0xffff) * 64)) * 1024;
}
}
if (bios_extmem == 0) {
v86.ctl = 0;
v86.addr = 0x15; /* int 0x15 function 0x88*/
v86.eax = 0x8800;
v86int();
bios_extmem = (v86.eax & 0xffff) * 1024;
}
/* Set memtop to actual top of memory */
memtop = 0x100000 + bios_extmem;
}
|
