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Diffstat (limited to 'sys/boot/pc98/boot2/start.S')
| -rw-r--r-- | sys/boot/pc98/boot2/start.S | 475 |
1 files changed, 475 insertions, 0 deletions
diff --git a/sys/boot/pc98/boot2/start.S b/sys/boot/pc98/boot2/start.S new file mode 100644 index 0000000..2a9bcbb --- /dev/null +++ b/sys/boot/pc98/boot2/start.S @@ -0,0 +1,475 @@ +/* + * 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 + * $FreeBSD$ + */ + +/* + 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 |
