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a27f4645 | 1 | /* |
a27f4645 RM |
2 | * Mach Operating System |
3 | * Copyright (c) 1992, 1991 Carnegie Mellon University | |
4 | * All Rights Reserved. | |
5 | * | |
6 | * Permission to use, copy, modify and distribute this software and its | |
7 | * documentation is hereby granted, provided that both the copyright | |
8 | * notice and this permission notice appear in all copies of the | |
9 | * software, derivative works or modified versions, and any portions | |
10 | * thereof, and that both notices appear in supporting documentation. | |
11 | * | |
12 | * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" | |
13 | * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR | |
14 | * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. | |
15 | * | |
16 | * Carnegie Mellon requests users of this software to return to | |
17 | * | |
18 | * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU | |
19 | * School of Computer Science | |
20 | * Carnegie Mellon University | |
21 | * Pittsburgh PA 15213-3890 | |
22 | * | |
23 | * any improvements or extensions that they make and grant Carnegie Mellon | |
24 | * the rights to redistribute these changes. | |
a27f4645 | 25 | * |
e4270b63 | 26 | * from: Mach, Revision 2.2 92/04/04 11:35:26 rpd |
fe139ecb | 27 | * $Id: boot2.S,v 1.2 1993/10/16 19:11:33 rgrimes Exp $ |
a27f4645 RM |
28 | */ |
29 | ||
30 | #include "asm.h" | |
31 | ||
32 | /* Conventional GDT indexes. */ | |
33 | #define BOOT_CS_INDEX 3 | |
34 | #define BOOT_CS16_INDEX 5 | |
35 | #define BOOT_DS_INDEX 4 | |
36 | #define DB_CS_INDEX 14 | |
37 | #define DB_CS16_INDEX 15 | |
38 | #define DB_DS_INDEX 16 | |
39 | #define GDT_INDEX 17 | |
40 | ||
41 | /* Vector numbers. */ | |
42 | #define BREAKPOINT_VECTOR 3 | |
43 | #define DEBUG_VECTOR 1 | |
44 | ||
45 | /* | |
46 | * boot2() -- second stage boot | |
47 | */ | |
48 | ||
49 | .globl EXT(ouraddr) | |
50 | ||
51 | ENTRY(boot2) | |
52 | data32 | |
53 | subl %eax, %eax | |
54 | mov %cs, %ax | |
55 | mov %ax, %ds | |
56 | mov %ax, %es | |
57 | data32 | |
58 | shll $4, %eax | |
59 | addr32 | |
60 | data32 | |
61 | movl %eax, EXT(ouraddr) | |
62 | ||
63 | /* fix up GDT entries for bootstrap */ | |
64 | #define FIXUP(gdt_index) \ | |
65 | addr32; \ | |
66 | movl %eax, EXT(Gdt)+(8*gdt_index)+2; /* actually movw %ax */ \ | |
67 | addr32; \ | |
68 | movb %bl, EXT(Gdt)+(8*gdt_index)+4 | |
69 | ||
70 | data32 | |
71 | shld $16, %eax, %ebx | |
72 | FIXUP(BOOT_CS_INDEX) | |
73 | FIXUP(BOOT_CS16_INDEX) | |
74 | FIXUP(BOOT_DS_INDEX) | |
75 | ||
76 | /* fix up GDT entry for GDT, and GDT and IDT pointers */ | |
77 | data32 | |
78 | movl %eax, %ecx | |
79 | data32 | |
80 | addl $ EXT(Gdt), %eax | |
81 | data32 | |
82 | shld $16, %eax, %ebx | |
83 | FIXUP(GDT_INDEX) | |
84 | addr32 | |
85 | data32 | |
86 | movl %eax, EXT(Gdtr)+2 | |
87 | data32 | |
88 | addl $ EXT(Idt), %ecx | |
89 | addr32 | |
90 | data32 | |
91 | movl %ecx, EXT(Idtr_prot)+2 | |
92 | ||
93 | /* %es = vector table segment for a while */ | |
94 | push %es | |
95 | data32 | |
96 | subl %eax, %eax | |
97 | mov %ax, %es | |
98 | ||
99 | /* fix up GDT entries for bdb */ | |
100 | data32 | |
101 | movl $4*DEBUG_VECTOR, %esi | |
102 | addr32 | |
103 | movl %es: 2(%esi), %eax /* actually movw to %ax */ | |
104 | data32 | |
105 | shll $4, %eax | |
106 | data32 | |
107 | shld $16, %eax, %ebx | |
108 | FIXUP(DB_CS_INDEX) | |
109 | FIXUP(DB_CS16_INDEX) | |
110 | FIXUP(DB_DS_INDEX) | |
111 | ||
112 | /* Fetch entry points of bdb's protected mode trap handlers. These | |
113 | * are stored at 2 before the corresponding entry points for real mode. | |
114 | */ | |
115 | data32 | |
116 | subl %ebx, %ebx | |
117 | addr32 | |
118 | movl %es: (%esi), %ebx /* actually movw to %bx */ | |
119 | data32 | |
120 | subl %ecx, %ecx | |
121 | addr32 | |
122 | movl %es: 4*(BREAKPOINT_VECTOR-DEBUG_VECTOR)(%esi), %ecx | |
123 | /* actually movw to %cx */ | |
124 | ||
125 | /* %es = bdb segment for a while */ | |
126 | data32 | |
127 | shrl $4, %eax | |
128 | mov %ax, %es | |
129 | ||
130 | /* fix up IDT entries for bdb */ | |
fe139ecb RG |
131 | subl $2, %ebx |
132 | movl %es: (%ebx), %eax /* actually movw to %ax */ | |
a27f4645 RM |
133 | addr32 |
134 | movl %eax, EXT(Idt)+8*DEBUG_VECTOR /* actually movw %ax */ | |
fe139ecb RG |
135 | subl $2, %ecx |
136 | movl %es: (%ecx), %eax /* actually movw to %ax */ | |
a27f4645 RM |
137 | addr32 |
138 | movl %eax, EXT(Idt)+8*BREAKPOINT_VECTOR /* actually movw %ax */ | |
139 | ||
140 | /* finished with groping in real mode segments */ | |
141 | pop %es | |
142 | ||
143 | /* change to protected mode */ | |
144 | data32 | |
145 | call EXT(real_to_prot) | |
146 | ||
147 | /* clear the bss */ | |
148 | movl $ EXT(edata), %edi /* no EXT(_edata) - krufty ld */ | |
149 | movl $ EXT(end), %ecx /* or EXT(_end) */ | |
150 | subl %edi, %ecx | |
151 | subb %al, %al | |
152 | rep | |
153 | stosb | |
154 | ||
155 | movzbl %dl, %edx /* discard head (%dh) and random high bits */ | |
156 | pushl %edx | |
157 | call EXT(boot) | |
158 | oops: | |
159 | hlt | |
160 | jmp oops | |
161 | ||
162 | .data | |
163 | .align 2 | |
164 | #if 0 /* XXX this would give losing "_ouraddr :". Better declared in C */ | |
165 | EXT(ouraddr): | |
166 | #else | |
167 | _ouraddr: | |
168 | #endif | |
169 | .long 0 |