projects / unix-history / blame
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|---|---|---|
| 986db2a9 WJ |
1 | /*- |
| 2 | * Copyright (c) 1990 The Regents of the University of California. | |
| 3 | * All rights reserved. | |
| 4 | * | |
| 5 | * This code is derived from software contributed to Berkeley by | |
| 6 | * William Jolitz. | |
| 7 | * | |
| 8 | * Redistribution and use in source and binary forms, with or without | |
| 9 | * modification, are permitted provided that the following conditions | |
| 10 | * are met: | |
| 11 | * 1. Redistributions of source code must retain the above copyright | |
| 12 | * notice, this list of conditions and the following disclaimer. | |
| 13 | * 2. Redistributions in binary form must reproduce the above copyright | |
| 14 | * notice, this list of conditions and the following disclaimer in the | |
| 15 | * documentation and/or other materials provided with the distribution. | |
| 16 | * 3. All advertising materials mentioning features or use of this software | |
| 17 | * must display the following acknowledgement: | |
| 18 | * This product includes software developed by the University of | |
| 19 | * California, Berkeley and its contributors. | |
| 20 | * 4. Neither the name of the University nor the names of its contributors | |
| 21 | * may be used to endorse or promote products derived from this software | |
| 22 | * without specific prior written permission. | |
| 23 | * | |
| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND | |
| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | |
| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE | |
| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE | |
| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL | |
| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS | |
| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | |
| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT | |
| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY | |
| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF | |
| 34 | * SUCH DAMAGE. | |
| 35 | * | |
| 36 | * @(#)fdbootblk.c 7.2 (Berkeley) 5/4/91 | |
| 37 | */ | |
| 38 | ||
| 39 | /* | |
| 40 | * fdbootblk.s: | |
| 41 | * Written 10/6/90 by William F. Jolitz | |
| 42 | * Initial block boot for AT/386 with typical stupid NEC controller | |
| 43 | * | |
| 44 | * Goal is to read in sucessive 7.5Kbytes of bootstrap to | |
| 45 | * execute. | |
| 46 | * | |
| 47 | * No attempt is made to handle disk errors. | |
| 48 | */ | |
| 49 | /*#include "/sys/i386/isa/isa.h" | |
| 50 | #include "/sys/i386/isa/fdreg.h"*/ | |
| 51 | #define NOP inb $0x84,%al | |
| 52 | #define BIOSRELOC 0x7c00 | |
| 53 | #define start RELOC+0x400 | |
| 54 | ||
| 55 | /* mumbo-jumbo to pacify DOS, in the hope of getting diskcopy to work */ | |
| 56 | jmp 1f | |
| 57 | .asciz "386BSD " | |
| 58 | .byte 1 # sectors per allocation | |
| 59 | .word 15 # additional sectors for bootstrap | |
| 60 | .word 0 # number of DOS fat sectors | |
| 61 | .word 0 # number of DOS rootdir entries | |
| 62 | .byte 0xf0 # media descriptor | |
| 63 | .word 0 # number of sectors per a DOS fat entry | |
| 64 | .word 18 # number of sectors per track | |
| 65 | .word 2 # number of heads | |
| 66 | .long 0 # number of hidden sectors | |
| 67 | .long 2880-18 # logical sectors per volume | |
| 68 | .byte 0 # physical drive | |
| 69 | .byte 0x29 # ? | |
| 70 | .long 137 # binary id | |
| 71 | .ascii "Release 0.1" # volume label | |
| 72 | .space 5 | |
| 73 | 1: | |
| 74 | /* step 0 force descriptors to bottom of address space */ | |
| 75 | ||
| 76 | cli | |
| 77 | .byte 0xb8,0x30,0x00 /* mov $0x30,%ax */ | |
| 78 | mov %ax, %ss | |
| 79 | .byte 0xbc,0x00,0x01 /* mov $0x100,%sp */ | |
| 80 | ||
| 81 | xorl %eax,%eax | |
| 82 | movl %ax,%ds | |
| 83 | movl %ax,%es | |
| 84 | ||
| 85 | /* obtain BIOS parameters for hard disk XXX */ | |
| 86 | movb $0x9f,%ah /* write to 0x9ff00 XXX */ | |
| 87 | movb $0xf0,%al | |
| 88 | mov %ax,%es | |
| 89 | xor %edi,%edi | |
| 90 | ||
| 91 | .byte 0xf, 0xb4, 0x36 ; .word 0x41*4 /* lfs 0x41*4, %si */ | |
| 92 | xorb %ch,%ch | |
| 93 | movb $0x10,%cl | |
| 94 | fs | |
| 95 | rep | |
| 96 | movsb | |
| 97 | ||
| 98 | .byte 0xf, 0xb4, 0x36 ; .word 0x46*4 /* lfs 0x46*4, %si */ | |
| 99 | xorb %ch,%ch | |
| 100 | movb $0x10,%cl | |
| 101 | fs | |
| 102 | rep | |
| 103 | movsb | |
| 104 | ||
| 105 | xorl %eax,%eax | |
| 106 | movl %ax,%es | |
| 107 | ||
| 108 | /* step 1 load new descriptor table */ | |
| 109 | ||
| 110 | .byte 0x2E,0x0F,1,0x16 /* word aword cs lgdt GDTptr */ | |
| 111 | .word BIOSRELOC+0xa4 #GDTptr | |
| 112 | ||
| 113 | /* step 2 turn on protected mode */ | |
| 114 | ||
| 115 | smsw %ax | |
| 116 | orb $1,%al | |
| 117 | lmsw %ax | |
| 118 | jmp 1f | |
| 119 | nop | |
| 120 | ||
| 121 | /* step 3 reload segment descriptors */ | |
| 122 | ||
| 123 | 1: | |
| 124 | xorl %eax,%eax | |
| 125 | movb $0x10,%al | |
| 126 | movl %ax,%ds | |
| 127 | movl %ax,%es | |
| 128 | movl %ax,%ss | |
| 129 | word | |
| 130 | ljmp $0x8,$ BIOSRELOC+0xb3 /* would be nice if .-RELOC+0x7c00 worked */ | |
| 131 | ||
| 132 | /* Global Descriptor Table contains three descriptors: | |
| 133 | * 0x00: Null: not used | |
| 134 | * 0x08: Code: code segment starts at 0 and extents for 4 gigabytes | |
| 135 | * 0x10: Data: data segment starts at 0 and extends for 4 gigabytes | |
| 136 | * (overlays code) | |
| 137 | */ | |
| 138 | GDT: | |
| 139 | NullDesc: .word 0,0,0,0 # null descriptor - not used | |
| 140 | CodeDesc: .word 0xFFFF # limit at maximum: (bits 15:0) | |
| 141 | .byte 0,0,0 # base at 0: (bits 23:0) | |
| 142 | .byte 0x9f # present/priv level 0/code/conforming/readable | |
| 143 | .byte 0xcf # page granular/default 32-bit/limit(bits 19:16) | |
| 144 | .byte 0 # base at 0: (bits 31:24) | |
| 145 | DataDesc: .word 0xFFFF # limit at maximum: (bits 15:0) | |
| 146 | .byte 0,0,0 # base at 0: (bits 23:0) | |
| 147 | .byte 0x93 # present/priv level 0/data/expand-up/writeable | |
| 148 | .byte 0xcf # page granular/default 32-bit/limit(bits 19:16) | |
| 149 | .byte 0 # base at 0: (bits 31:24) | |
| 150 | ||
| 151 | /* Global Descriptor Table pointer | |
| 152 | * contains 6-byte pointer information for LGDT | |
| 153 | */ | |
| 154 | GDTptr: .word 0x17 # limit to three 8 byte selectors(null,code,data) | |
| 155 | .long BIOSRELOC+0x8c # GDT -- arrgh, gas again! | |
| 156 | readcmd: .byte 0xe6,0,0,0,0,2,18,0x1b,0xff | |
| 157 | ||
| 158 | /* step 4 relocate to final bootstrap address. */ | |
| 159 | reloc: | |
| 160 | movl $ BIOSRELOC,%esi | |
| 161 | movl $ RELOC,%edi | |
| 162 | movl $512,%ecx | |
| 163 | rep | |
| 164 | movsb | |
| 165 | movl $0xa0000, %esp | |
| 166 | pushl $dodisk | |
| 167 | ret | |
| 168 | ||
| 169 | /* step 5 load remaining 15 sectors off disk */ | |
| 170 | dodisk: | |
| 171 | movl $ RELOC+0x200, %edi | |
| 172 | xorl %ebx, %ebx | |
| 173 | incb %bl # shl $1,%bl | |
| 174 | incb %bl | |
| 175 | movb $0x20,%al # do a eoi | |
| 176 | outb %al,$0x20 | |
| 177 | ||
| 178 | NOP | |
| 179 | movb $0x07,%al | |
| 180 | outb %al,$0x21 | |
| 181 | NOP | |
| 182 | 8: | |
| 183 | movb %bl,readcmd+4 | |
| 184 | movl %edi,%ecx | |
| 185 | ||
| 186 | /* Set read/write bytes */ | |
| 187 | xorl %edx,%edx | |
| 188 | movb $0x0c,%dl # outb(0xC,0x46); outb(0xB,0x46); | |
| 189 | movb $0x46,%al | |
| 190 | outb %al,%dx | |
| 191 | NOP | |
| 192 | decb %dx | |
| 193 | outb %al,%dx | |
| 194 | ||
| 195 | /* Send start address */ | |
| 196 | movb $0x04,%dl # outb(0x4, addr); | |
| 197 | movb %cl,%al | |
| 198 | outb %al,%dx | |
| 199 | NOP | |
| 200 | movb %ch,%al # outb(0x4, addr>>8); | |
| 201 | outb %al,%dx | |
| 202 | NOP | |
| 203 | rorl $8,%ecx # outb(0x81, addr>>16); | |
| 204 | movb %ch,%al | |
| 205 | outb %al,$0x81 | |
| 206 | NOP | |
| 207 | ||
| 208 | /* Send count */ | |
| 209 | movb $0x05,%dl # outb(0x5, 0); | |
| 210 | xorl %eax,%eax | |
| 211 | outb %al,%dx | |
| 212 | NOP | |
| 213 | movb $2,%al # outb(0x5,2); | |
| 214 | outb %al,%dx | |
| 215 | NOP | |
| 216 | ||
| 217 | /* set channel 2 */ | |
| 218 | movb $2,%al # outb(0x0A,2); | |
| 219 | outb %al,$0x0A | |
| 220 | NOP | |
| 221 | ||
| 222 | /* issue read command to fdc */ | |
| 223 | movw $0x3f4,%dx | |
| 224 | movl $readcmd,%esi | |
| 225 | xorl %ecx,%ecx | |
| 226 | movb $9,%cl | |
| 227 | ||
| 228 | 2: NOP | |
| 229 | inb %dx,%al | |
| 230 | testb $0x80,%al | |
| 231 | jz 2b | |
| 232 | ||
| 233 | incb %dx | |
| 234 | NOP | |
| 235 | movl (%esi),%al | |
| 236 | outb %al,%dx | |
| 237 | NOP | |
| 238 | incl %esi | |
| 239 | decb %dx | |
| 240 | loop 2b | |
| 241 | ||
| 242 | /* watch the icu looking for an interrupt signalling completion */ | |
| 243 | xorl %edx,%edx | |
| 244 | movb $0x20,%dl | |
| 245 | 2: | |
| 246 | NOP | |
| 247 | movb $0xc,%al | |
| 248 | outb %al,%dx | |
| 249 | NOP | |
| 250 | inb %dx,%al | |
| 251 | andb $0x7f,%al | |
| 252 | cmpb $6,%al | |
| 253 | jne 2b | |
| 254 | NOP | |
| 255 | movb $0x20,%al # do a eoi | |
| 256 | outb %al,%dx | |
| 257 | NOP | |
| 258 | ||
| 259 | movl $0x3f4,%edx | |
| 260 | xorl %ecx,%ecx | |
| 261 | movb $7,%cl | |
| 262 | 2: | |
| 263 | NOP | |
| 264 | inb %dx,%al | |
| 265 | andb $0xC0,%al | |
| 266 | cmpb $0xc0,%al | |
| 267 | jne 2b | |
| 268 | incb %dx | |
| 269 | inb %dx,%al | |
| 270 | decb %dx | |
| 271 | loop 2b | |
| 272 | ||
| 273 | /* extract the status bytes after the read. must we do this? */ | |
| 274 | addw $0x200,%edi # next addr to load to | |
| 275 | incb %bl | |
| 276 | cmpb $15,%bl | |
| 277 | jle 8b | |
| 278 | ||
| 279 | /* for clever bootstrap, dig out boot unit and cylinder */ | |
| 280 | pushl $0 | |
| 281 | pushl $0 | |
| 282 | ||
| 283 | /* fd controller is major device 2 */ | |
| 284 | pushl $2 /* dev */ | |
| 285 | ||
| 286 | /* sorry, no flags at this point! */ | |
| 287 | ||
| 288 | movl $ start, %eax | |
| 289 | call %eax /* main (dev, unit, off) */ | |
| 290 | ||
| 291 | ebootblkcode: | |
| 292 | ||
| 293 | /* remaining space usable for a disk label */ | |
| 294 | ||
| 295 | .org 0x1fe | |
| 296 | .word 0xaa55 /* signature -- used by BIOS ROM */ | |
| 297 | ||
| 298 | ebootblk: /* MUST BE EXACTLY 0x200 BIG FOR SURE */ |