/* * Mach Operating System * Copyright (c) 1992, 1991 Carnegie Mellon University * All Rights Reserved. * * Permission to use, copy, modify and distribute this software and its * documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie Mellon * the rights to redistribute these changes. * * from: Mach, Revision 2.2 92/04/04 11:36:29 rpd * $FreeBSD: src/sys/boot/pc98/boot2/start.S,v 1.5 2002/05/14 12:34:03 nyan Exp $ * $DragonFly: src/sys/boot/pc98/boot2/Attic/start.S,v 1.3 2003/11/10 06:08:38 dillon Exp $ */ /* Copyright 1988, 1989, 1990, 1991, 1992 by Intel Corporation, Santa Clara, California. All Rights Reserved Permission to use, copy, modify, and distribute this software and its documentation for any purpose and without fee is hereby granted, provided that the above copyright notice appears in all copies and that both the copyright notice and this permission notice appear in supporting documentation, and that the name of Intel not be used in advertising or publicity pertaining to distribution of the software without specific, written prior permission. INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT, NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* * Ported to PC-9801 by Yoshio Kimura */ #include "asm.h" .file "start.S" SIGNATURE= 0xaa55 LOADSZ= 8192 /* size of unix boot */ NAMEBLOCKMAGIC= 0xfadefeed /* value of magicnumebr for block2 */ /* * This DEBUGMSG(msg) macro may be useful for debugging. Its use is * restricted to this file since it only works in real mode. */ #define DEBUGMSG(msg) \ data32 ; \ mov $msg, %esi ; \ data32 ; \ call message .code16 .text .globl start start: jmp main boot_cyl: .word 0 String "IPL1 " main: /* set up %ds */ xor %ax, %ax mov %ax, %ds /* set up %ss and %esp */ mov $BOOTSEG, %eax mov %ax, %ss /* * make a little room on the stack for * us to save the default bootstring we might find.. * effectively, we push the bootstring. */ mov $BOOTSTACK-64, %esp /* set up %es, (where we will load boot2 to) */ mov %ax, %es push %es push %ecx push %dx mov $0xa000, %eax mov %ax, %es /* set up graphic screen */ movb $0x42, %ah movb $0xc0, %ch int $0x18 movb $0x40, %ah int $0x18 mov $0x0a00, %eax /* 80 x 25 mode */ int $0x18 movb $0x0c, %ah /* text on */ int $0x18 /* cursor home and on */ xor %dx, %dx movb $0x13, %ah int $0x18 movb $0x11, %ah int $0x18 /* keyboad reset */ movb $0x03, %ah int $0x18 /* transfer PC-9801 system common area to 0xa1000 */ mov $0x0000, %esi mov $0x1000, %edi mov $0x0630, %ecx cld rep movsb /* transfer EPSON machine type to 0xa1200 */ push %ds mov $0xfd00, %eax mov %ax, %ds mov 0x804, %eax and $0x00ffffff, %eax mov %eax, %es: (0x1624) pop %ds pop %dx pop %ecx pop %es /* bootstrap passes */ mov %cs, %bx cmp $0x1fe0, %bx jz fd cmp $0x1fc0, %bx jnz hd xor %cx, %cx movb 0x584, %al andb $0xf0, %al cmpb $0x30, %al jz fd cmpb $0x90, %al jnz hd fd: mov $0x0200, %cx mov $0x0001, %dx movb $0xd6, %ah jmp load hd: and %cx, %cx jnz 1f .code32 addr32 mov %cs: (boot_cyl), %ecx /* actualy %cx in real mode */ .code16 1: xor %dx, %dx movb $0x06, %ah /* * BIOS call "INT 0x1B Function 0xn6" to read sectors from disk into memory * Call with %ah = 0xd6(for floppy disk) or 0x06(for hard disk) * %al = DA/UA * %bx = data length * %ch = sector size(for floppy) or cylinder(for hard) * %cl = cylinder * %dh = head * %dl = sector * %es:%bp = segment:offset of buffer * Return: * %ah = 0x0 on success; err code on failure */ load: #ifdef NAMEBLOCK /* * Load the second sector and see if it is a boot instruction block. * If it is then scan the contents for the first valid string and copy it to * the location of the default boot string.. then zero it out. * Finally write the block back to disk with the zero'd out entry.. * I hate writing at this stage but we need this to be persistant. * If the boot fails, then the next boot will get the next string. * /etc/rc will regenerate a complete block2 iff the boot succeeds. * * Format of block 2 is: * [NAMEBLOCKMAGIC] <--0xdeafc0de * [nulls] * [bootstring]NULL <---e.g. 0:wd(0,a)/kernel.experimental * [bootstring]NULL <---e.g. 0:wd(0,a)/kernel.old * .... * [bootstring]NULL <---e.g. 0:wd(0,f)/kernel * FF FF FF */ where: /* * save things we might smash * (that are not smashed immedatly after us anyway.) */ data32 push %ecx /* preserve 'cyl,sector ' */ data32 push %edx /* * Load the second sector * BIOS call "INT 0x13 Function 0x2" to read sectors from disk into memory * Call with %ah = 0x2 * %al = number of sectors * %ch = cylinder * %cl = sector * %dh = head * %dl = drive (0x80 for hard disk, 0x0 for floppy disk) * %es:%bx = segment:offset of buffer * Return: * %al = 0x0 on success; err code on failure */ data32 movl $0x0201, %eax /function 2 (read) 1 sector */ xor %ebx, %ebx /* %bx = 0 */ /* buffer address (ES:0) */ data32 movl $0x0002, %ecx /* sector 2, cylinder 0 */ data32 andl $0x00ff, %edx /* head 0, drive N */ int $0x13 data32 jb read_error /* * confirm that it is one for us */ data32 xorl %ebx, %ebx /* magic number at start of buffer */ data32 addr32 movl %es:(%ebx), %eax data32 cmpl $NAMEBLOCKMAGIC, %eax data32 jne notours /* not ours so return to caller */ /* * scan for a bootstring * Skip the magic number, and scan till we find a non-null, * or a -1 */ incl %ebx /* quicker and smaller */ incl %ebx incl %ebx scan: incl %ebx addr32 movb %es:(%ebx), %al /* load the next byte */ testb %al, %al /* and if it is null */ data32 /* keep scanning (past deleted entries) */ jz scan incb %al /* now look for -1 */ data32 jz notours /* if we reach the 0xFF then we have finished */ /* * save our settings.. we need them twice.. */ data32 push %ebx /* * copy it to the default string location * which is just above the stack for 64 bytes. */ data32 movl $BOOTSTACK-64, %ecx /* 64 bytes at the top of the stack */ nxtbyte: addr32 movb %es:(%ebx), %al /* get the next byte in */ addr32 movb %al, %es:(%ecx) /* and transfer it to the name buffer */ incl %ebx /* get on with the next byte */ incl %ecx /* get on with the next byte */ testb %al, %al /* if it was 0 then quit this */ data32 jnz nxtbyte /* and looop if more to do */ /* * restore the saved settings and * zero it out so next time we don't try it again */ data32 pop %ebx /* get back our starting location */ #ifdef NAMEBLOCK_WRITEBACK nxtbyte2: addr32 movb %es:(%ebx), %al /* get the byte */ addr32 movb $0, %es:(%ebx) /* zero it out */ data32 incl %ebx /* point to the next byte */ testb %al, %al /* check if we have finished.. */ data32 jne nxtbyte2 /* * Write the second sector back * Load the second sector * BIOS call "INT 0x13 Function 0x3" to write sectors from memory to disk * Call with %ah = 0x3 * %al = number of sectors * %ch = cylinder * %cl = sector * %dh = head * %dl = drive (0x80 for hard disk, 0x0 for floppy disk) * %es:%bx = segment:offset of buffer * Return: * %al = 0x0 on success; err code on failure */ data32 movl $0x0301, %eax /* write 1 sector */ xor %ebx, %ebx /* buffer is at offset 0 */ data32 movl $0x0002, %ecx /* block 2 */ data32 andl $0xff, %edx /* head 0 */ int $0x13 data32 jnb notours data32 mov $eread, %esi jmp err_stop #endif /* NAMEBLOCK_WRITEBACK */ /* * return to the main-line */ notours: data32 pop %edx data32 pop %ecx #endif mov $LOADSZ, %ebx movb 0x584, %al xor %bp, %bp /* %bp = 0, put it at 0 in the BOOTSEG */ int $0x1b jc read_error /* * ljmp to the second stage boot loader (boot2). * After ljmp, %cs is BOOTSEG and boot1 (512 bytes) will be used * as an internal buffer "intbuf". */ .code32 data32 ljmp $BOOTSEG, $ EXT(boot2) .code16 /* * read_error */ read_error: mov $eread, %esi err_stop: call message jmp stop /* * message: write the error message in %ds:%esi to console */ message: push %eax push %ebx push %ds push %es mov $0xe000, %dx mov 0x501, %al testb $0x08, %al jnz 1f mov $0xa000, %dx 1: mov %dx, %es mov %cs, %ax mov %ax, %ds mov vram, %di mov $0x00e1, %bx mov $160, %cx cld nextb: lodsb /* load a byte into %al */ cmpb $0x0, %al je done cmpb $0x0d, %al je cr_code cmpb $0x0a, %al je lf_code movb %bl, %es:0x2000(%di) stosb inc %di jmp move_cursor lf_code: add %cx, %di jmp move_cursor cr_code: xor %dx, %dx mov %di, %ax div %cx sub %dx, %di move_cursor: mov %di, %dx movb $0x13, %ah int $0x18 jmp nextb done: mov %di, vram pop %es pop %ds pop %ebx pop %eax ret stop: hlt jmp stop /* halt doesnt actually halt forever */ vram: .word 0 /* error messages */ #ifdef DEBUG one: String "1-\0" two: String "2-\0" three: String "3-\0" four: String "4-\0" #endif /* DEBUG */ #ifdef NAMEBLOCK_WRITEBACK ewrite: String "Write error\r\n\0" #endif /* NAMEBLOCK_WRITEBACK */ eread: String "Read error\r\n\0" enoboot: String "No bootable partition\r\n\0" endofcode: . = EXT(start) + 0x1be /* Partition table */ .fill 0x30,0x1,0x0 .byte 0x80, 0x00, 0x01, 0x00 .byte 0xa5, 0xff, 0xff, 0xff .byte 0x00, 0x00, 0x00, 0x00 .byte 0x50, 0xc3, 0x00, 0x00 /* the last 2 bytes in the sector 0 contain the signature */ .value SIGNATURE ENTRY(disklabel) . = EXT(start) + 0x400