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
|
/*
* Copyright (c) 1995-1997 University of Utah and the Flux Group.
*
* This file is part of the OSKit Linux Boot Loader, which is free software,
* also known as "open source;" you can redistribute it and/or modify it under
* the terms of the GNU General Public License (GPL), version 2, as published
* by the Free Software Foundation (FSF).
*
* The OSKit is distributed in the hope that it will be useful, but WITHOUT ANY
* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GPL for more details. You should have
* received a copy of the GPL along with the OSKit; see the file COPYING. If
* not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
*/
#include <oskit/x86/asm.h>
/* NOTE! These had better be the same as in bootsect.s! */
#include <linux/config.h>
#define INITSEG DEF_INITSEG /* we move boot here - out of the way */
#define SYSSEG DEF_SYSSEG /* system loaded at 0x10000 (65536). */
#define SETUPSEG DEF_SETUPSEG /* this is the current segment */
#define HIGHSECS 5 /* nr of sectors loaded at INITSEG */
#define STACK_SIZE 4096
.text
.code16
/*
* Entrypoint from Linux boot loaders such as LILO.
*
* Note that whereas in the Linux 16-bit boot code,
* the 'bootsect' and 'setup' fragments are compiled and linked separately,
* in this code they are linked into one big small-model binary image.
* This means that, whereas the Linux setup code expects to run at 9020:0000,
* this setup code wants to run at 9000:0200.
* Since LILO and other Linux boot loaders will be starting us at 9020:0000,
* we need to fix the CS and EIP early on to conform to our environment.
* That's what the ljmp instruction below is for.
*/
setup_entry:
cld
/* Move the rest of the linuxboot code and data up from SYSSEG. */
movw $SYSSEG,%ax
movw %ax,%ds
movw $INITSEG,%ax
movw %ax,%es
xorw %si,%si
movw $HIGHSECS*512,%di
movl $EXT(edata)-HIGHSECS*512,%ecx
rep
movsb
/* Jump to the segment we want to be running in. */
ljmp $INITSEG,$0f
0:
movw %ax,%ds
/* Switch to a stack in the same segment as everything else. */
movw %ax,%ss
movl $stack+STACK_SIZE,%esp
.comm stack,STACK_SIZE
/* Clear our BSS segment. */
movl $EXT(edata),%edi
movl $EXT(end),%ecx
subw %di,%cx
xorb %al,%al
cld
rep
stosb
/* Make backtraces terminate */
xorl %ebp,%ebp
jmp EXT(i16_bios_main)
|
