/* $NetBSD: bios_disk.S,v 1.18 2005/12/11 12:17:48 christos Exp $ */ /* * Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992 * * 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. */ /* 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. */ /* extracted from netbsd:sys/arch/i386/boot/bios.S */ #include /* * BIOS call "INT 0x13 Function 0x0" to reset the disk subsystem * Call with %ah = 0x0 * %dl = drive (0x80 for hard disk, 0x0 for floppy disk) * Return: * %al = 0x0 on success; err code on failure */ ENTRY(biosdisk_reset) pushl %ebp movl %esp, %ebp pushl %ebx push %edx push %edi movb 8(%ebp), %dl # device call _C_LABEL(prot_to_real) # enter real mode .code16 movb $0x0, %ah # subfunction int $0x13 setc %bl movb %ah, %bh # save error code calll _C_LABEL(real_to_prot) # back to protected mode .code32 xorl %eax, %eax movw %bx, %ax # return value in %ax pop %edi pop %edx popl %ebx popl %ebp ret /* * 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 * * biosdisk_read(dev, cyl, head, sect, count, buff_addr); * * Note: On failure, you must reset the disk with biosdisk_reset() before * sending another command. */ ENTRY(biosdisk_read) pushl %ebp movl %esp, %ebp pushl %ebx push %ecx push %edx push %esi push %edi movb 16(%ebp), %dh movw 12(%ebp), %cx xchgb %ch, %cl # cylinder; the highest 2 bits of cyl is in %cl rorb $2, %cl movb 20(%ebp), %al orb %al, %cl incb %cl # sector; sec starts from 1, not 0 movb 8(%ebp), %dl # device movl 28(%ebp), %ebx # buffer address (may be >64k) movb 24(%ebp), %al # number of sectors call _C_LABEL(prot_to_real) # enter real mode .code16 push %bx shrl $4, %ebx # max segment mov %ds, %si add %si, %bx mov %bx, %es # %es:%bx now valid buffer address pop %bx and $0xf, %bx # and min offset - to avoid overrun movb $0x2, %ah # subfunction int $0x13 setc %al # error code is in %ah calll _C_LABEL(real_to_prot) # back to protected mode .code32 andl $0xffff, %eax pop %edi pop %esi pop %edx pop %ecx popl %ebx popl %ebp ret /* * biosdisk_getinfo(int dev): return a word that represents the * max number of sectors, heads and cylinders for this device */ ENTRY(biosdisk_getinfo) pushl %ebp movl %esp, %ebp push %es pushl %ebx push %ecx push %edx push %esi push %edi movb 8(%ebp), %dl # diskinfo(drive #) call _C_LABEL(prot_to_real) # enter real mode .code16 push %dx # save drive # movb $0x08, %ah # ask for disk info int $0x13 pop %bx # restore drive # jnc ok testb $0x80, %bl # is it a hard disk? jnz ok /* * Urk. Call failed. It is not supported for floppies by old BIOS's. * Guess it's a 15-sector floppy. Initialize all the registers for * documentation, although we only need head and sector counts. */ xorw %ax, %ax # set status to success # movb %ah, %bh # %bh = 0 # movb $2, %bl # %bl bits 0-3 = drive type, 2 = 1.2M movb $79, %ch # max track movb $15, %cl # max sector movb $1, %dh # max head # movb $1, %dl # # floppy drives installed # es:di = parameter table # carry = 0 ok: calll _C_LABEL(real_to_prot) # back to protected mode .code32 /* form a longword representing all this gunk */ shrl $8, %eax # clear unnecessary bits shll $24, %eax shll $16, %ecx # do the same for %ecx shrl $8, %ecx movb %dh, %cl # max head orl %ecx, %eax # return value in %eax pop %edi pop %esi pop %edx pop %ecx popl %ebx pop %es popl %ebp ret /* * int biosdisk_int13ext(int dev): * check for availibility of int13 extensions. */ ENTRY(biosdisk_int13ext) pushl %ebp movl %esp, %ebp pushl %ebx pushl %ecx pushl %edx pushl %esi pushl %edi movb 8(%ebp), %dl # drive # movw $0x55aa, %bx call _C_LABEL(prot_to_real) # enter real mode .code16 movb $0x41, %ah # ask for disk info int $0x13 setnc %dl calll _C_LABEL(real_to_prot) # switch back .code32 xorl %eax, %eax movb %dl, %al # return value in %ax cmpw $0xaa55, %bx sete %dl andb %dl, %al andb %cl, %al popl %edi popl %esi popl %edx popl %ecx popl %ebx popl %ebp ret /* * BIOS call "INT 0x13 Function 0x42" to read sectors from disk into memory * Call with %ah = 0x42 * %ds:%si = parameter block (data buffer address * must be a real mode physical address). * %dl = drive (0x80 for hard disk, 0x0 for floppy disk) * Return: * %al = 0x0 on success; err code on failure */ ENTRY(biosdisk_extread) pushl %ebp movl %esp, %ebp pushl %ebx push %ecx push %edx push %esi push %edi movb 8(%ebp), %dl # device movl 12(%ebp), %esi # parameter block call _C_LABEL(prot_to_real) # enter real mode .code16 movl %esi, %eax shrl $4, %eax movw %ds, %bx addw %bx, %ax movw %ax, %ds andw $0xf, %si movb $0x42, %ah # subfunction int $0x13 setc %bl movb %ah, %bh # save error code calll _C_LABEL(real_to_prot) # back to protected mode .code32 xorl %eax, %eax movw %bx, %ax # return value in %ax pop %edi pop %esi pop %edx pop %ecx popl %ebx popl %ebp ret ENTRY(biosdisk_getextinfo) pushl %ebp movl %esp, %ebp pushl %ebx push %ecx push %edx push %esi push %edi movb 8(%ebp), %dl # device movl 12(%ebp), %esi # parameter block call _C_LABEL(prot_to_real) # enter real mode .code16 movl %esi, %eax shrl $4, %eax andw $0xf, %si movw %ds, %bx addw %bx, %ax movw %ax, %ds movb $0x48, %ah # subfunction int $0x13 setc %bl calll _C_LABEL(real_to_prot) # back to protected mode .code32 xorl %eax, %eax movb %bl, %al # return value in %ax pop %edi pop %esi pop %edx pop %ecx popl %ebx popl %ebp ret