| cdboot.S (86164) | cdboot.S (123476) |
|---|---|
| 1# 2# Copyright (c) 2001 John Baldwin 3# All rights reserved. 4# 5# Redistribution and use in source and binary forms are freely 6# permitted provided that the above copyright notice and this 7# paragraph and the following disclaimer are duplicated in all 8# such forms. 9# 10# This software is provided "AS IS" and without any express or 11# implied warranties, including, without limitation, the implied 12# warranties of merchantability and fitness for a particular 13# purpose. 14# 15 | 1# 2# Copyright (c) 2001 John Baldwin 3# All rights reserved. 4# 5# Redistribution and use in source and binary forms are freely 6# permitted provided that the above copyright notice and this 7# paragraph and the following disclaimer are duplicated in all 8# such forms. 9# 10# This software is provided "AS IS" and without any express or 11# implied warranties, including, without limitation, the implied 12# warranties of merchantability and fitness for a particular 13# purpose. 14# 15 |
| 16# $FreeBSD: head/sys/boot/i386/cdboot/cdboot.s 86164 2001-11-07 01:20:33Z jhb $ | 16# $FreeBSD: head/sys/boot/i386/cdboot/cdboot.s 123476 2003-12-11 22:42:50Z jhb $ |
| 17 18# 19# This program is a freestanding boot program to load an a.out binary 20# from a CD-ROM booted with no emulation mode as described by the El 21# Torito standard. Due to broken BIOSen that do not load the desired 22# number of sectors, we try to fit this in as small a space as possible. 23# 24# Basically, we first create a set of boot arguments to pass to the loaded --- 109 unchanged lines hidden (view full) --- 134 pop %eax # Prepare to 135 inc %eax # try next 136 cmpb $VD_END,(%bx) # Last VD? 137 jne load_vd # No, read next 138 mov $msg_novd,%si # No VD 139 jmp error # Halt 140have_vd: # Have Primary VD 141# | 17 18# 19# This program is a freestanding boot program to load an a.out binary 20# from a CD-ROM booted with no emulation mode as described by the El 21# Torito standard. Due to broken BIOSen that do not load the desired 22# number of sectors, we try to fit this in as small a space as possible. 23# 24# Basically, we first create a set of boot arguments to pass to the loaded --- 109 unchanged lines hidden (view full) --- 134 pop %eax # Prepare to 135 inc %eax # try next 136 cmpb $VD_END,(%bx) # Last VD? 137 jne load_vd # No, read next 138 mov $msg_novd,%si # No VD 139 jmp error # Halt 140have_vd: # Have Primary VD 141# |
| 142# Lookup the loader binary. | 142# Try to look up the loader binary using the paths in the loader_paths 143# array. |
| 143# | 144# |
| 144 mov $loader_path,%si # File to lookup 145 call lookup # Try to find it | 145 mov $loader_paths,%si # Point to start of array 146lookup_path: push %si # Save file name pointer 147 call lookup # Try to find file 148 pop %di # Restore file name pointer 149 jnc lookup_found # Found this file 150 xor %al,%al # Look for next 151 mov $0xffff,%cx # path name by 152 repnz # scanning for 153 scasb # nul char 154 inc %di # Skip nul 155 mov %di,%si # Point %si at next path 156 mov (%si),%al # Get first char of next path 157 or %al,%al # Is it double nul? 158 jnz lookup_path # No, try it. 159 mov $msg_failed,%si # Failed message 160 jmp error # Halt 161lookup_found: # Found a loader file |
| 146# 147# Load the binary into the buffer. Due to real mode addressing limitations 148# we have to read it in in 64k chunks. 149# 150 mov DIR_SIZE(%bx),%eax # Read file length 151 add $SECTOR_SIZE-1,%eax # Convert length to sectors 152 shr $11,%eax 153 cmp $BUFFER_LEN,%eax --- 107 unchanged lines hidden (view full) --- 261 mov $msg_jump,%si # Display the 262 call putstr # jump message 263 ljmp $0,$MEM_BTX_ENTRY # Jump to the BTX entry point 264 265# 266# Lookup the file in the path at [SI] from the root directory. 267# 268# Trashes: All but BX | 162# 163# Load the binary into the buffer. Due to real mode addressing limitations 164# we have to read it in in 64k chunks. 165# 166 mov DIR_SIZE(%bx),%eax # Read file length 167 add $SECTOR_SIZE-1,%eax # Convert length to sectors 168 shr $11,%eax 169 cmp $BUFFER_LEN,%eax --- 107 unchanged lines hidden (view full) --- 277 mov $msg_jump,%si # Display the 278 call putstr # jump message 279 ljmp $0,$MEM_BTX_ENTRY # Jump to the BTX entry point 280 281# 282# Lookup the file in the path at [SI] from the root directory. 283# 284# Trashes: All but BX |
| 269# Returns: BX = pointer to record | 285# Returns: CF = 0 (success), BX = pointer to record 286# CF = 1 (not found) |
| 270# 271lookup: mov $VD_ROOTDIR+MEM_VOLDESC,%bx # Root directory record 272 push %si 273 mov $msg_lookup,%si # Display lookup message 274 call putstr 275 pop %si 276 push %si 277 call putstr 278 mov $msg_lookup2,%si 279 call putstr 280 pop %si 281lookup_dir: lodsb # Get first char of path 282 cmp $0,%al # Are we done? 283 je lookup_done # Yes 284 cmp $'/',%al # Skip path separator. 285 je lookup_dir 286 dec %si # Undo lodsb side effect 287 call find_file # Lookup first path item 288 jnc lookup_dir # Try next component | 287# 288lookup: mov $VD_ROOTDIR+MEM_VOLDESC,%bx # Root directory record 289 push %si 290 mov $msg_lookup,%si # Display lookup message 291 call putstr 292 pop %si 293 push %si 294 call putstr 295 mov $msg_lookup2,%si 296 call putstr 297 pop %si 298lookup_dir: lodsb # Get first char of path 299 cmp $0,%al # Are we done? 300 je lookup_done # Yes 301 cmp $'/',%al # Skip path separator. 302 je lookup_dir 303 dec %si # Undo lodsb side effect 304 call find_file # Lookup first path item 305 jnc lookup_dir # Try next component |
| 289 mov $msg_lookupfail,%si # Not found. | 306 mov $msg_lookupfail,%si # Not found message 307 call putstr 308 stc # Set carry 309 ret |
| 290 jmp error 291lookup_done: mov $msg_lookupok,%si # Success message 292 call putstr | 310 jmp error 311lookup_done: mov $msg_lookupok,%si # Success message 312 call putstr |
| 313 clc # Clear carry |
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| 293 ret 294 295# 296# Lookup file at [SI] in directory whose record is at [BX]. 297# 298# Trashes: All but returns | 314 ret 315 316# 317# Lookup file at [SI] in directory whose record is at [BX]. 318# 319# Trashes: All but returns |
| 299# Returns: CF = 0 (success), BX = pointer to record, SX = next path item | 320# Returns: CF = 0 (success), BX = pointer to record, SI = next path item |
| 300# CF = 1 (not found), SI = preserved 301# 302find_file: mov DIR_EXTENT(%bx),%eax # Load extent 303 xor %edx,%edx 304 mov DIR_EA_LEN(%bx),%dl 305 add %edx,%eax # Skip extended attributes 306 mov %eax,rec_lba # Save LBA 307 mov DIR_SIZE(%bx),%eax # Save size --- 223 unchanged lines hidden (view full) --- 531# State for searching dir 532# 533rec_lba: .long 0x0 # LBA (adjusted for EA) 534rec_size: .long 0x0 # File size 535name_len: .byte 0x0 # Length of current name 536 537twiddle_index: .byte 0x0 538 | 321# CF = 1 (not found), SI = preserved 322# 323find_file: mov DIR_EXTENT(%bx),%eax # Load extent 324 xor %edx,%edx 325 mov DIR_EA_LEN(%bx),%dl 326 add %edx,%eax # Skip extended attributes 327 mov %eax,rec_lba # Save LBA 328 mov DIR_SIZE(%bx),%eax # Save size --- 223 unchanged lines hidden (view full) --- 552# State for searching dir 553# 554rec_lba: .long 0x0 # LBA (adjusted for EA) 555rec_size: .long 0x0 # File size 556name_len: .byte 0x0 # Length of current name 557 558twiddle_index: .byte 0x0 559 |
| 539msg_welcome: .asciz "CD Loader 1.01\r\n\n" | 560msg_welcome: .asciz "CD Loader 1.2\r\n\n" |
| 540msg_bootinfo: .asciz "Building the boot loader arguments\r\n" 541msg_relocate: .asciz "Relocating the loader and the BTX\r\n" 542msg_jump: .asciz "Starting the BTX loader\r\n" 543msg_badread: .ascii "Read Error: 0x" 544hex_error: .ascii "00\r\n" 545msg_novd: .asciz "Could not find Primary Volume Descriptor\r\n" 546msg_lookup: .asciz "Looking up " 547msg_lookup2: .asciz "... " 548msg_lookupok: .asciz "Found\r\n" 549msg_lookupfail: .asciz "File not found\r\n" 550msg_load2big: .asciz "File too big\r\n" | 561msg_bootinfo: .asciz "Building the boot loader arguments\r\n" 562msg_relocate: .asciz "Relocating the loader and the BTX\r\n" 563msg_jump: .asciz "Starting the BTX loader\r\n" 564msg_badread: .ascii "Read Error: 0x" 565hex_error: .ascii "00\r\n" 566msg_novd: .asciz "Could not find Primary Volume Descriptor\r\n" 567msg_lookup: .asciz "Looking up " 568msg_lookup2: .asciz "... " 569msg_lookupok: .asciz "Found\r\n" 570msg_lookupfail: .asciz "File not found\r\n" 571msg_load2big: .asciz "File too big\r\n" |
| 551loader_path: .asciz "/BOOT/LOADER" | 572msg_failed: .asciz "Boot failed\r\n" |
| 552twiddle_chars: .ascii "|/-\\" | 573twiddle_chars: .ascii "|/-\\" |
| 574loader_paths: .asciz "/BOOT/LOADER" 575 .asciz "/boot/loader" 576 .byte 0 |
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| 553 | 577 |