Commit | Line | Data |
---|---|---|
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 RG |
26 | * from: Mach, Revision 2.2 92/04/04 11:34:13 rpd |
27 | * $Id$ | |
a27f4645 RM |
28 | */ |
29 | ||
e4270b63 | 30 | |
a27f4645 RM |
31 | /* |
32 | Copyright 1988, 1989, 1990, 1991, 1992 | |
33 | by Intel Corporation, Santa Clara, California. | |
34 | ||
35 | All Rights Reserved | |
36 | ||
37 | Permission to use, copy, modify, and distribute this software and | |
38 | its documentation for any purpose and without fee is hereby | |
39 | granted, provided that the above copyright notice appears in all | |
40 | copies and that both the copyright notice and this permission notice | |
41 | appear in supporting documentation, and that the name of Intel | |
42 | not be used in advertising or publicity pertaining to distribution | |
43 | of the software without specific, written prior permission. | |
44 | ||
45 | INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE | |
46 | INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, | |
47 | IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR | |
48 | CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM | |
49 | LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, | |
50 | NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION | |
51 | WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. | |
52 | */ | |
53 | ||
54 | .file "asm.s" | |
55 | ||
56 | #include "asm.h" | |
57 | ||
58 | ||
59 | CR0_PE_ON = 0x1 | |
60 | CR0_PE_OFF = 0xfffffffe | |
61 | ||
62 | .globl _ouraddr | |
63 | .text | |
64 | ||
65 | /* | |
66 | # | |
67 | # real_to_prot() | |
68 | # transfer from real mode to protected mode. | |
69 | */ | |
70 | ||
71 | ENTRY(real_to_prot) | |
72 | # guarantee that interrupt is disabled when in prot mode | |
73 | cli | |
74 | ||
75 | # load the gdtr | |
76 | addr32 | |
77 | data32 | |
78 | lgdt EXT(Gdtr) | |
79 | ||
80 | # set the PE bit of CR0 | |
81 | mov %cr0, %eax | |
82 | ||
83 | data32 | |
84 | or $CR0_PE_ON, %eax | |
85 | mov %eax, %cr0 | |
86 | ||
87 | # make intrasegment jump to flush the processor pipeline and | |
88 | # reload CS register | |
89 | data32 | |
90 | ljmp $0x18, $xprot | |
91 | ||
92 | xprot: | |
93 | # we are in USE32 mode now | |
94 | # set up the protected mode segment registers : DS, SS, ES | |
95 | mov $0x20, %eax | |
96 | movw %ax, %ds | |
97 | movw %ax, %ss | |
98 | movw %ax, %es | |
99 | ||
100 | # load idtr so we can debug | |
101 | lidt EXT(Idtr_prot) | |
102 | ||
103 | ret | |
104 | ||
105 | /* | |
106 | # | |
107 | # prot_to_real() | |
108 | # transfer from protected mode to real mode | |
109 | # | |
110 | */ | |
111 | ||
112 | ENTRY(prot_to_real) | |
113 | ||
114 | # set up a dummy stack frame for the second seg change. | |
115 | movl _ouraddr, %eax | |
116 | sarl $4, %eax | |
117 | pushw %ax | |
118 | movw $xreal, %ax # gas botches pushw $xreal - extra bytes 0, 0 | |
119 | pushw %ax # decode to add %al, (%eax) (%al usually 0) | |
120 | ||
121 | # Change to use16 mode. | |
122 | ljmp $0x28, $x16 | |
123 | ||
124 | x16: | |
125 | # clear the PE bit of CR0 | |
126 | mov %cr0, %eax | |
127 | data32 | |
128 | and $CR0_PE_OFF, %eax | |
129 | mov %eax, %cr0 | |
130 | ||
131 | # make intersegment jmp to flush the processor pipeline | |
132 | # using the fake stack frame set up earlier | |
133 | # and reload CS register | |
134 | lret | |
135 | ||
136 | xreal: | |
137 | # we are in real mode now | |
138 | # set up the real mode segment registers : DS, SS, ES | |
139 | movw %cs, %ax | |
140 | movw %ax, %ds | |
141 | movw %ax, %ss | |
142 | movw %ax, %es | |
143 | ||
144 | # load idtr so we can debug | |
145 | addr32 | |
146 | data32 | |
147 | lidt EXT(Idtr_real) | |
148 | ||
149 | data32 | |
150 | ret | |
151 | ||
152 | /* | |
153 | # | |
154 | # startprog(phyaddr) | |
155 | # start the program on protected mode where phyaddr is the entry point | |
156 | # | |
157 | */ | |
158 | ||
159 | ENTRY(startprog) | |
160 | push %ebp | |
161 | mov %esp, %ebp | |
162 | ||
163 | # get things we need into registers | |
164 | movl 0x8(%ebp), %ecx # entry offset | |
165 | movl 0x0c(%ebp), %eax # &argv | |
166 | ||
167 | # make a new stack at 0:0xa0000 (big segs) | |
168 | mov $0x10, %ebx | |
169 | movw %bx, %ss | |
170 | movl $0xa0000, %ebx | |
171 | movl %ebx, %esp | |
172 | ||
173 | # push some number of args onto the stack | |
174 | pushl $0 # nominally a cyl offset in the boot. | |
175 | pushl 0x8(%eax) # argv[2] = bootdev | |
176 | pushl 0x4(%eax) # argv[1] = howto | |
177 | pushl $0 # dummy 'return' address | |
178 | ||
179 | # push on our entry address | |
180 | mov $0x08, %ebx # segment | |
181 | pushl %ebx | |
182 | pushl %ecx | |
183 | ||
184 | # convert over the other data segs | |
185 | mov $0x10, %ebx | |
186 | movw %bx, %ds | |
187 | movw %bx, %es | |
188 | ||
189 | # convert the PC (and code seg) | |
190 | lret | |
191 | /* | |
192 | # | |
193 | # pbzero( dst, cnt) | |
194 | # where src is a virtual address and dst is a physical address | |
195 | */ | |
196 | ||
197 | ENTRY(pbzero) | |
198 | push %ebp | |
199 | mov %esp, %ebp | |
200 | push %es | |
201 | push %esi | |
202 | push %edi | |
203 | push %ecx | |
204 | ||
205 | cld | |
206 | ||
207 | # set %es to point at the flat segment | |
208 | mov $0x10, %eax | |
209 | movw %ax, %es | |
210 | ||
211 | mov 0x8(%ebp), %edi # destination | |
212 | mov 0xc(%ebp), %ecx # count | |
213 | mov $0x0, %eax # value | |
214 | ||
215 | rep | |
216 | stosb | |
217 | ||
218 | pop %ecx | |
219 | pop %edi | |
220 | pop %esi | |
221 | pop %es | |
222 | pop %ebp | |
223 | ||
224 | ret | |
225 | /* | |
226 | # | |
227 | # pcpy(src, dst, cnt) | |
228 | # where src is a virtual address and dst is a physical address | |
229 | # | |
230 | */ | |
231 | ||
232 | ENTRY(pcpy) | |
233 | push %ebp | |
234 | mov %esp, %ebp | |
235 | push %es | |
236 | push %esi | |
237 | push %edi | |
238 | push %ecx | |
239 | ||
240 | cld | |
241 | ||
242 | # set %es to point at the flat segment | |
243 | mov $0x10, %eax | |
244 | movw %ax, %es | |
245 | ||
246 | mov 0x8(%ebp), %esi # source | |
247 | mov 0xc(%ebp), %edi # destination | |
248 | mov 0x10(%ebp), %ecx # count | |
249 | ||
250 | rep | |
251 | movsb | |
252 | ||
253 | pop %ecx | |
254 | pop %edi | |
255 | pop %esi | |
256 | pop %es | |
257 | pop %ebp | |
258 | ||
259 | ret | |
260 |