| Current Path : /sys/boot/pc98/cdboot/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/boot/pc98/cdboot/cdboot.S |
# # Copyright (c) 2006 TAKAHASHI Yoshihiro <nyan@FreeBSD.org> # Copyright (c) 2001 John Baldwin <jhb@FreeBSD.org> # All rights reserved. # # Redistribution and use in source and binary forms, with or without # modification, are permitted provided that the following conditions # are met: # 1. Redistributions of source code must retain the above copyright # notice, this list of conditions and the following disclaimer. # 2. Redistributions in binary form must reproduce the above copyright # notice, this list of conditions and the following disclaimer in the # documentation and/or other materials provided with the distribution. # 3. Neither the name of the author nor the names of any co-contributors # may be used to endorse or promote products derived from this software # without specific prior written permission. # # THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND # ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE # IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE # ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE # FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL # DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS # OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) # HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY # OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF # SUCH DAMAGE. # # $FreeBSD: release/9.1.0/sys/boot/pc98/cdboot/cdboot.S 237763 2012-06-29 10:12:18Z avg $ #include <bootargs.h> # # Basically, we first create a set of boot arguments to pass to the loaded # binary. Then we attempt to load /boot/loader from the CD we were booted # off of. # # # Memory locations. # .set STACK_OFF,0x6000 # Stack offset .set LOAD_SEG,0x0700 # Load segment .set LOAD_SIZE,2048 # Load size .set DAUA,0x0584 # DA/UA .set MEM_PAGE_SIZE,0x1000 # memory page size, 4k .set MEM_ARG,0x900 # Arguments at start .set MEM_ARG_BTX,0xa100 # Where we move them to so the # BTX client can see them .set MEM_ARG_SIZE,0x18 # Size of the arguments .set MEM_BTX_ADDRESS,0x9000 # where BTX lives .set MEM_BTX_ENTRY,0x9010 # where BTX starts to execute .set MEM_BTX_OFFSET,MEM_PAGE_SIZE # offset of BTX in the loader .set MEM_BTX_CLIENT,0xa000 # where BTX clients live # # PC98 machine type from sys/pc98/pc98/pc98_machdep.h # .set MEM_SYS, 0xa100 # System common area segment .set PC98_MACHINE_TYPE, 0x0620 # PC98 machine type .set EPSON_ID, 0x0624 # EPSON machine id .set M_NEC_PC98, 0x0001 .set M_EPSON_PC98, 0x0002 .set M_NOT_H98, 0x0010 .set M_H98, 0x0020 .set M_NOTE, 0x0040 .set M_NORMAL, 0x1000 .set M_8M, 0x8000 # # Signature Constants # .set SIG1_OFF,0x1fe # Signature offset .set SIG2_OFF,0x7fe # Signature offset # # a.out header fields # .set AOUT_TEXT,0x04 # text segment size .set AOUT_DATA,0x08 # data segment size .set AOUT_BSS,0x0c # zero'd BSS size .set AOUT_SYMBOLS,0x10 # symbol table .set AOUT_ENTRY,0x14 # entry point .set AOUT_HEADER,MEM_PAGE_SIZE # size of the a.out header # # Segment selectors. # .set SEL_SDATA,0x8 # Supervisor data .set SEL_RDATA,0x10 # Real mode data .set SEL_SCODE,0x18 # PM-32 code .set SEL_SCODE16,0x20 # PM-16 code # # BTX constants # .set INT_SYS,0x30 # BTX syscall interrupt # # Constants for reading from the CD. # .set ERROR_TIMEOUT,0x90 # BIOS timeout on read .set NUM_RETRIES,3 # Num times to retry .set SECTOR_SIZE,0x800 # size of a sector .set SECTOR_SHIFT,11 # number of place to shift .set BUFFER_LEN,0x100 # number of sectors in buffer .set MAX_READ,0xf800 # max we can read at a time .set MAX_READ_SEC,MAX_READ >> SECTOR_SHIFT .set MEM_READ_BUFFER,0x9000 # buffer to read from CD .set MEM_VOLDESC,MEM_READ_BUFFER # volume descriptor .set MEM_DIR,MEM_VOLDESC+SECTOR_SIZE # Lookup buffer .set VOLDESC_LBA,0x10 # LBA of vol descriptor .set VD_PRIMARY,1 # Primary VD .set VD_END,255 # VD Terminator .set VD_ROOTDIR,156 # Offset of Root Dir Record .set DIR_LEN,0 # Offset of Dir Record length .set DIR_EA_LEN,1 # Offset of EA length .set DIR_EXTENT,2 # Offset of 64-bit LBA .set DIR_SIZE,10 # Offset of 64-bit length .set DIR_NAMELEN,32 # Offset of 8-bit name len .set DIR_NAME,33 # Offset of dir name # # Program start. # .code16 .globl start start: jmp main .org 4 .ascii "IPL1 " main: cld /* Setup the stack */ xor %ax,%ax mov %ax,%ss mov $STACK_OFF,%sp push %ecx /* Setup graphic screen */ mov $0x42,%ah # 640x400 mov $0xc0,%ch int $0x18 mov $0x40,%ah # graph on int $0x18 /* Setup text screen */ mov $0x0a00,%ax # 80x25 int $0x18 mov $0x0c,%ah # text on int $0x18 mov $0x13,%ah # cursor home xor %dx,%dx int $0x18 mov $0x11,%ah # cursor on int $0x18 /* Setup keyboard */ mov $0x03,%ah int $0x18 /* Transfer PC-9801 system common area */ xor %ax,%ax mov %ax,%si mov %ax,%ds mov %ax,%di mov $MEM_SYS,%ax mov %ax,%es mov $0x0600,%cx rep movsb /* Transfer EPSON machine type */ mov $0xfd00,%ax mov %ax,%ds mov (0x804),%eax and $0x00ffffff,%eax mov %eax,%es:(EPSON_ID) /* Set machine type to PC98_SYSTEM_PARAMETER */ call machine_check /* Load cdboot */ xor %ax,%ax mov %ax,%ds mov $0x06,%ah /* Read data */ mov (DAUA),%al /* Read drive */ pop %ecx /* cylinder */ xor %dx,%dx /* head / sector */ mov $LOAD_SEG,%bx /* Load address */ mov %bx,%es xor %bp,%bp mov $LOAD_SIZE,%bx /* Load size */ int $0x1b mov $msg_readerr,%si jc error /* Jump to cdboot */ ljmp $LOAD_SEG,$cdboot # # Set machine type to PC98_SYSTEM_PARAMETER. # machine_check: xor %edx,%edx mov %dx,%ds mov $MEM_SYS,%ax mov %ax,%es /* Wait V-SYNC */ vsync.1: inb $0x60,%al test $0x20,%al jnz vsync.1 vsync.2: inb $0x60,%al test $0x20,%al jz vsync.2 /* ANK 'A' font */ xor %al,%al outb %al,$0xa1 mov $0x41,%al outb %al,$0xa3 /* Get 'A' font from CG window */ push %ds mov $0xa400,%ax mov %ax,%ds xor %eax,%eax xor %bx,%bx mov $4,%cx font.1: add (%bx),%eax add $4,%bx loop font.1 pop %ds cmp $0x6efc58fc,%eax jnz m_epson m_pc98: or $M_NEC_PC98,%edx mov $0x0458,%bx mov (%bx),%al test $0x80,%al jz m_not_h98 or $M_H98,%edx jmp 1f m_epson: or $M_EPSON_PC98,%edx m_not_h98: or $M_NOT_H98,%edx 1: inb $0x42,%al test $0x20,%al jz 1f or $M_8M,%edx 1: mov $0x0400,%bx mov (%bx),%al test $0x80,%al jz 1f or $M_NOTE,%edx 1: mov $PC98_MACHINE_TYPE,%bx mov %edx,%es:(%bx) ret # # Print out the error message at [SI], wait for a keypress, and then # reboot the machine. # error: call putstr mov $msg_keypress,%si call putstr xor %ax,%ax # Get keypress int $0x18 xor %ax,%ax # CPU reset outb %al,$0xf0 halt: hlt jmp halt # Spin # # Display a null-terminated string at [SI]. # # Trashes: AX, BX, CX, DX, SI, DI # putstr: push %ds push %es mov %cs,%ax mov %ax,%ds mov $0xa000,%ax mov %ax,%es mov cursor,%di mov $0x00e1,%bx # Attribute mov $160,%cx putstr.0: lodsb testb %al,%al jz putstr.done cmp $0x0d,%al jz putstr.cr cmp $0x0a,%al jz putstr.lf mov %bl,%es:0x2000(%di) stosb inc %di jmp putstr.move putstr.cr: xor %dx,%dx mov %di,%ax div %cx sub %dx,%di jmp putstr.move putstr.lf: add %cx,%di putstr.move: mov %di,%dx mov $0x13,%ah # Move cursor int $0x18 jmp putstr.0 putstr.done: mov %di,cursor pop %es pop %ds ret # # Display a single char at [AL], but don't move a cursor. # putc: push %es push %di push %bx mov $0xa000,%bx mov %bx,%es mov cursor,%di mov $0xe1,%bl # Attribute mov %bl,%es:0x2000(%di) stosb pop %bx pop %di pop %es ret msg_readerr: .asciz "Read Error\r\n" msg_keypress: .asciz "\r\nPress any key to reboot\r\n" /* Boot signature */ .org SIG1_OFF,0x90 .word 0xaa55 # Magic number # # cdboot # cdboot: mov %cs,%ax mov %ax,%ds xor %ax,%ax mov %ax,%es mov %es:(DAUA),%al # Save BIOS boot device mov %al,drive mov %cx,cylinder # Save BIOS boot cylinder mov $msg_welcome,%si # %ds:(%si) -> welcome message call putstr # display the welcome message # # Setup the arguments that the loader is expecting from boot[12] # mov $msg_bootinfo,%si # %ds:(%si) -> boot args message call putstr # display the message mov $MEM_ARG,%bx # %ds:(%bx) -> boot args mov %bx,%di # %es:(%di) -> boot args xor %eax,%eax # zero %eax mov $(MEM_ARG_SIZE/4),%cx # Size of arguments in 32-bit # dwords rep # Clear the arguments stosl # to zero mov drive,%dl # Store BIOS boot device mov %dl,%es:0x4(%bx) # in kargs->bootdev or $KARGS_FLAGS_CD,%es:0x8(%bx) # kargs->bootflags |= # KARGS_FLAGS_CD # # Load Volume Descriptor # mov $VOLDESC_LBA,%eax # Set LBA of first VD load_vd: push %eax # Save %eax mov $1,%dh # One sector mov $MEM_VOLDESC,%ebx # Destination call read # Read it in cmpb $VD_PRIMARY,%es:(%bx) # Primary VD? je have_vd # Yes pop %eax # Prepare to inc %eax # try next cmpb $VD_END,%es:(%bx) # Last VD? jne load_vd # No, read next mov $msg_novd,%si # No VD jmp error # Halt have_vd: # Have Primary VD # # Try to look up the loader binary using the paths in the loader_paths # array. # mov $loader_paths,%si # Point to start of array lookup_path: push %si # Save file name pointer call lookup # Try to find file pop %di # Restore file name pointer jnc lookup_found # Found this file push %es mov %cs,%ax mov %ax,%es xor %al,%al # Look for next mov $0xffff,%cx # path name by repnz # scanning for scasb # nul char pop %es mov %di,%si # Point %si at next path mov (%si),%al # Get first char of next path or %al,%al # Is it double nul? jnz lookup_path # No, try it. mov $msg_failed,%si # Failed message jmp error # Halt lookup_found: # Found a loader file # # Load the binary into the buffer. Due to real mode addressing limitations # we have to read it in 64k chunks. # mov %es:DIR_SIZE(%bx),%eax # Read file length add $SECTOR_SIZE-1,%eax # Convert length to sectors shr $SECTOR_SHIFT,%eax cmp $BUFFER_LEN,%eax jbe load_sizeok mov $msg_load2big,%si # Error message jmp error load_sizeok: movzbw %al,%cx # Num sectors to read mov %es:DIR_EXTENT(%bx),%eax # Load extent xor %edx,%edx mov %es:DIR_EA_LEN(%bx),%dl add %edx,%eax # Skip extended mov $MEM_READ_BUFFER,%ebx # Read into the buffer load_loop: mov %cl,%dh cmp $MAX_READ_SEC,%cl # Truncate to max read size jbe load_notrunc mov $MAX_READ_SEC,%dh load_notrunc: sub %dh,%cl # Update count push %eax # Save call read # Read it in pop %eax # Restore add $MAX_READ_SEC,%eax # Update LBA add $MAX_READ,%ebx # Update dest addr jcxz load_done # Done? jmp load_loop # Keep going load_done: # # Turn on the A20 address line # xor %ax,%ax # Turn A20 on outb %al,$0xf2 mov $0x02,%al outb %al,$0xf6 # # Relocate the loader and BTX using a very lazy protected mode # mov $msg_relocate,%si # Display the call putstr # relocation message mov %es:(MEM_READ_BUFFER+AOUT_ENTRY),%edi # %edi is the destination mov $(MEM_READ_BUFFER+AOUT_HEADER),%esi # %esi is # the start of the text # segment mov %es:(MEM_READ_BUFFER+AOUT_TEXT),%ecx # %ecx = length of the text # segment push %edi # Save entry point for later lgdt gdtdesc # setup our own gdt cli # turn off interrupts mov %cr0,%eax # Turn on or $0x1,%al # protected mov %eax,%cr0 # mode ljmp $SEL_SCODE,$pm_start # long jump to clear the # instruction pre-fetch queue .code32 pm_start: mov $SEL_SDATA,%ax # Initialize mov %ax,%ds # %ds and mov %ax,%es # %es to a flat selector rep # Relocate the movsb # text segment add $(MEM_PAGE_SIZE - 1),%edi # pad %edi out to a new page and $~(MEM_PAGE_SIZE - 1),%edi # for the data segment mov MEM_READ_BUFFER+AOUT_DATA,%ecx # size of the data segment rep # Relocate the movsb # data segment mov MEM_READ_BUFFER+AOUT_BSS,%ecx # size of the bss xor %eax,%eax # zero %eax add $3,%cl # round %ecx up to shr $2,%ecx # a multiple of 4 rep # zero the stosl # bss mov MEM_READ_BUFFER+AOUT_ENTRY,%esi # %esi -> relocated loader add $MEM_BTX_OFFSET,%esi # %esi -> BTX in the loader mov $MEM_BTX_ADDRESS,%edi # %edi -> where BTX needs to go movzwl 0xa(%esi),%ecx # %ecx -> length of BTX rep # Relocate movsb # BTX ljmp $SEL_SCODE16,$pm_16 # Jump to 16-bit PM .code16 pm_16: mov $SEL_RDATA,%ax # Initialize mov %ax,%ds # %ds and mov %ax,%es # %es to a real mode selector mov %cr0,%eax # Turn off and $~0x1,%al # protected mov %eax,%cr0 # mode ljmp $LOAD_SEG,$pm_end # Long jump to clear the # instruction pre-fetch queue pm_end: sti # Turn interrupts back on now # # Copy the BTX client to MEM_BTX_CLIENT # mov %cs,%ax mov %ax,%ds xor %ax,%ax mov %ax,%es mov $MEM_BTX_CLIENT,%di # Prepare to relocate mov $btx_client,%si # the simple btx client mov $(btx_client_end-btx_client),%cx # length of btx client rep # Relocate the movsb # simple BTX client # # Copy the boot[12] args to where the BTX client can see them # xor %ax,%ax mov %ax,%ds mov $MEM_ARG,%si # where the args are at now mov $MEM_ARG_BTX,%di # where the args are moving to mov $(MEM_ARG_SIZE/4),%cx # size of the arguments in longs rep # Relocate movsl # the words # # Save the entry point so the client can get to it later on # pop %eax # Restore saved entry point stosl # and add it to the end of # the arguments # # Now we just start up BTX and let it do the rest # mov $msg_jump,%si # Display the call putstr # jump message ljmp $0,$MEM_BTX_ENTRY # Jump to the BTX entry point # # Lookup the file in the path at [SI] from the root directory. # # Trashes: All but BX # Returns: CF = 0 (success), BX = pointer to record # CF = 1 (not found) # lookup: mov $VD_ROOTDIR+MEM_VOLDESC,%bx # Root directory record push %bx push %si mov $msg_lookup,%si # Display lookup message call putstr pop %si push %si call putstr mov $msg_lookup2,%si call putstr pop %si pop %bx lookup_dir: lodsb # Get first char of path cmp $0,%al # Are we done? je lookup_done # Yes cmp $'/',%al # Skip path separator. je lookup_dir dec %si # Undo lodsb side effect call find_file # Lookup first path item jnc lookup_dir # Try next component mov $msg_lookupfail,%si # Not found message push %bx call putstr pop %bx stc # Set carry ret lookup_done: mov $msg_lookupok,%si # Success message push %bx call putstr pop %bx clc # Clear carry ret # # Lookup file at [SI] in directory whose record is at [BX]. # # Trashes: All but returns # Returns: CF = 0 (success), BX = pointer to record, SI = next path item # CF = 1 (not found), SI = preserved # find_file: mov %es:DIR_EXTENT(%bx),%eax # Load extent xor %edx,%edx mov %es:DIR_EA_LEN(%bx),%dl add %edx,%eax # Skip extended attributes mov %eax,rec_lba # Save LBA mov %es:DIR_SIZE(%bx),%eax # Save size mov %eax,rec_size xor %cl,%cl # Zero length push %si # Save ff.namelen: inc %cl # Update length lodsb # Read char cmp $0,%al # Nul? je ff.namedone # Yes cmp $'/',%al # Path separator? jnz ff.namelen # No, keep going ff.namedone: dec %cl # Adjust length and save mov %cl,name_len pop %si # Restore ff.load: mov rec_lba,%eax # Load LBA mov $MEM_DIR,%ebx # Address buffer mov $1,%dh # One sector call read # Read directory block incl rec_lba # Update LBA to next block ff.scan: mov %ebx,%edx # Check for EOF sub $MEM_DIR,%edx cmp %edx,rec_size ja ff.scan.1 stc # EOF reached ret ff.scan.1: cmpb $0,%es:DIR_LEN(%bx) # Last record in block? je ff.nextblock push %si # Save movzbw %es:DIR_NAMELEN(%bx),%si # Find end of string ff.checkver: cmpb $'0',%es:DIR_NAME-1(%bx,%si) # Less than '0'? jb ff.checkver.1 cmpb $'9',%es:DIR_NAME-1(%bx,%si) # Greater than '9'? ja ff.checkver.1 dec %si # Next char jnz ff.checkver jmp ff.checklen # All numbers in name, so # no version ff.checkver.1: movzbw %es:DIR_NAMELEN(%bx),%cx cmp %cx,%si # Did we find any digits? je ff.checkdot # No cmpb $';',%es:DIR_NAME-1(%bx,%si) # Check for semicolon jne ff.checkver.2 dec %si # Skip semicolon mov %si,%cx mov %cl,%es:DIR_NAMELEN(%bx) # Adjust length jmp ff.checkdot ff.checkver.2: mov %cx,%si # Restore %si to end of string ff.checkdot: cmpb $'.',%es:DIR_NAME-1(%bx,%si) # Trailing dot? jne ff.checklen # No decb %es:DIR_NAMELEN(%bx) # Adjust length ff.checklen: pop %si # Restore movzbw name_len,%cx # Load length of name cmp %cl,%es:DIR_NAMELEN(%bx) # Does length match? je ff.checkname # Yes, check name ff.nextrec: add %es:DIR_LEN(%bx),%bl # Next record adc $0,%bh jmp ff.scan ff.nextblock: subl $SECTOR_SIZE,rec_size # Adjust size jnc ff.load # If subtract ok, keep going ret # End of file, so not found ff.checkname: lea DIR_NAME(%bx),%di # Address name in record push %si # Save repe cmpsb # Compare name je ff.match # We have a winner! pop %si # Restore jmp ff.nextrec # Keep looking. ff.match: add $2,%sp # Discard saved %si clc # Clear carry ret # # Load DH sectors starting at LBA EAX into [EBX]. # # Trashes: EAX # read: push %es # Save push %bp push %dx push %cx push %ebx mov %bx,%bp # Set destination address and $0x000f,%bp shr $4,%ebx mov %bx,%es xor %bx,%bx # Set read bytes mov %dh,%bl shl $SECTOR_SHIFT,%bx # 2048 bytes/sec mov %ax,%cx # Set LBA shr $16,%eax mov %ax,%dx read.retry: mov $0x06,%ah # BIOS device read mov drive,%al and $0x7f,%al call twiddle # Entertain the user int $0x1b # Call BIOS jc read.fail # Worked? pop %ebx # Restore pop %cx pop %dx pop %bp pop %es ret # Return read.fail: cmp $ERROR_TIMEOUT,%ah # Timeout? je read.retry # Yes, Retry. read.error: mov %ah,%al # Save error mov $hex_error,%di # Format it call hex8 # as hex mov $msg_badread,%si # Display Read error message jmp error # # Output the "twiddle" # twiddle: push %ax # Save push %bx # Save mov twiddle_index,%al # Load index mov $twiddle_chars,%bx # Address table inc %al # Next and $3,%al # char mov %al,twiddle_index # Save index for next call xlat # Get char call putc # Output it pop %bx # Restore pop %ax # Restore ret # # Convert AL to hex, saving the result to [EDI]. # hex8: pushl %eax # Save shrb $0x4,%al # Do upper call hex8.1 # 4 popl %eax # Restore hex8.1: andb $0xf,%al # Get lower 4 cmpb $0xa,%al # Convert sbbb $0x69,%al # to hex das # digit orb $0x20,%al # To lower case mov %al,(%di) # Save char inc %di ret # (Recursive) # # BTX client to start btxldr # .code32 btx_client: mov $(MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE-4), %esi # %ds:(%esi) -> end # of boot[12] args mov $(MEM_ARG_SIZE/4),%ecx # Number of words to push std # Go backwards push_arg: lodsl # Read argument push %eax # Push it onto the stack loop push_arg # Push all of the arguments cld # In case anyone depends on this pushl MEM_ARG_BTX-MEM_BTX_CLIENT+MEM_ARG_SIZE # Entry point of # the loader push %eax # Emulate a near call mov $0x1,%eax # 'exec' system call int $INT_SYS # BTX system call btx_client_end: .code16 .p2align 4 # # Global descriptor table. # gdt: .word 0x0,0x0,0x0,0x0 # Null entry .word 0xffff,0x0000,0x9200,0x00cf # SEL_SDATA .word 0xffff,0x0000,0x9200,0x0000 # SEL_RDATA .word 0xffff,LOAD_SEG<<4,0x9a00,0x00cf # SEL_SCODE (32-bit) .word 0xffff,LOAD_SEG<<4,0x9a00,0x008f # SEL_SCODE16 (16-bit) gdt.1: # # Pseudo-descriptors. # gdtdesc: .word gdt.1-gdt-1 # Limit .long LOAD_SEG<<4 + gdt # Base # # BOOT device # drive: .byte 0 cylinder: .word 0 # # State for searching dir # rec_lba: .long 0x0 # LBA (adjusted for EA) rec_size: .long 0x0 # File size name_len: .byte 0x0 # Length of current name cursor: .word 0 twiddle_index: .byte 0x0 msg_welcome: .asciz "CD Loader 1.2\r\n\n" msg_bootinfo: .asciz "Building the boot loader arguments\r\n" msg_relocate: .asciz "Relocating the loader and the BTX\r\n" msg_jump: .asciz "Starting the BTX loader\r\n" msg_badread: .ascii "Read Error: 0x" hex_error: .asciz "00\r\n" msg_novd: .asciz "Could not find Primary Volume Descriptor\r\n" msg_lookup: .asciz "Looking up " msg_lookup2: .asciz "... " msg_lookupok: .asciz "Found\r\n" msg_lookupfail: .asciz "File not found\r\n" msg_load2big: .asciz "File too big\r\n" msg_failed: .asciz "Boot failed\r\n" twiddle_chars: .ascii "|/-\\" loader_paths: .asciz "/BOOT.PC98/LOADER" .asciz "/boot.pc98/loader" .asciz "/BOOT/LOADER" .asciz "/boot/loader" .byte 0 /* Boot signature */ .org SIG2_OFF,0x90 .word 0xaa55 # Magic number