/* $NetBSD: bios.S,v 1.13 1996/01/06 22:15:29 mycroft 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. */ #include #define addr32 .byte 0x67 #define data32 .byte 0x66 /* # 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 */ ENTRY(biosread) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %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 # offset # prot_to_real will set %es to BOOTSEG call _C_LABEL(prot_to_real) # enter real mode movb $0x2, %ah # subfunction addr32 movb 24(%ebp), %al # number of sectors int $0x13 setc %bl data32 call _C_LABEL(real_to_prot) # back to protected mode xorl %eax, %eax movb %bl, %al # return value in %ax popl %edi popl %esi popl %ebx popl %ebp ret #ifdef DOSREAD /* # MSDOS call "INT 0x21 Function 0x3d" to open a file. # Call with %ah = 0x3d # %al = 0x0 (access and sharing modes) # %ds:%dx = ASCIZ filename # %cl = attribute mask of files to look for */ ENTRY(dosexit) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi movl 0x8(%ebp), %ebx # exit code call _C_LABEL(prot_to_real) # enter real mode movb %bl, %al # exit code movb $0x4c , %ah # Exit int $0x21 cli hlt ENTRY(dosopen) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi movl 0x8(%ebp), %edx # File name. movb $0x0 , %cl # Attribute mask. call _C_LABEL(prot_to_real) # enter real mode movb $0x3d, %ah # Open existing file. movb $0x0 , %al # Compatibility mode int $0x21 jnc ok1 addr32 movl %eax, _C_LABEL(doserrno) data32 movl $-1, %eax ok1: pushl %eax data32 call _C_LABEL(real_to_prot) # back to protected mode xorl %eax, %eax popw %ax # return value in %eax popl %edi popl %esi popl %ebx popl %ebp ret ENTRY(dosread) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi movl 0x8(%ebp), %ebx # File handle movl 0xc(%ebp), %edx # Buffer. movl 0x10(%ebp) , %ecx # Bytes to read call _C_LABEL(prot_to_real) # enter real mode movb $0x3f, %ah # Read from file or device movb $0x0 , %al # Compatibility mode int $0x21 jnc ok2 addr32 movl %eax, _C_LABEL(doserrno) data32 movl $-1, %eax ok2: pushl %eax data32 call _C_LABEL(real_to_prot) # back to protected mode xorl %eax, %eax popw %ax # return value in %eax popl %edi popl %esi popl %ebx popl %ebp ret ENTRY(dosclose) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi movl 0x8(%ebp), %ebx # File handle call _C_LABEL(prot_to_real) # enter real mode movb $0x3e, %ah # Close file. movb $0x0 , %al # Compatibility mode int $0x21 jnc ok3 addr32 movl %eax, _C_LABEL(doserrno) data32 movl $-1, %eax ok3: pushl %eax data32 call _C_LABEL(real_to_prot) # back to protected mode xorl %eax, %eax popw %ax # return value in %eax popl %edi popl %esi popl %ebx popl %ebp ret #endif #ifndef SERIAL /* # BIOS call "INT 10H Function 0Eh" to write character to console # Call with %ah = 0x0e # %al = character # %bh = page # %bl = foreground color */ ENTRY(putc) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi movb 8(%ebp), %cl call _C_LABEL(prot_to_real) movb %cl, %al movb $0x0e, %ah data32 movl $0x0001, %ebx int $0x10 # display a byte data32 call _C_LABEL(real_to_prot) popl %edi popl %esi popl %ebx popl %ebp ret /* # BIOS call "INT 16H Function 00H" to read character from the keyboard # Call with %ah = 0x00 # Return: %ah = keyboard scan code # %al = ASCII character */ ENTRY(getc) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi call _C_LABEL(prot_to_real) movb $0x00, %ah int $0x16 movb %al, %bl # real_to_prot uses %eax data32 call _C_LABEL(real_to_prot) xorl %eax, %eax movb %bl, %al popl %edi popl %esi popl %ebx popl %ebp ret /* # BIOS call "INT 16H Function 01H" to check whether a character is pending # Call with %ah = 0x01 # Return: # If key waiting to be input: # %ah = keyboard scan code # %al = ASCII character # ZF = clear # else # ZF = set */ ENTRY(ischar) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi call _C_LABEL(prot_to_real) movb $0x01, %ah int $0x16 setnz %ah movb %ah, %bl # real_to_prot uses %eax data32 call _C_LABEL(real_to_prot) xorl %eax, %eax movb %bl, %al popl %edi popl %esi popl %ebx popl %ebp ret #endif /* #ifndef SERIAL */ /* # # get_diskinfo(): return a word that represents the # max number of sectors and heads and drives for this device # */ ENTRY(get_diskinfo) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi movb 8(%ebp), %dl # diskinfo(drive #) call _C_LABEL(prot_to_real) # enter real mode movb $0x08, %ah # ask for disk info int $0x13 jnc 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. */ subb %ah, %ah # %ax = 0 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: data32 call _C_LABEL(real_to_prot) # back to protected mode xorl %eax, %eax /*form a longword representing all this gunk*/ movb %dh, %ah # max head andb $0x3f, %cl # mask of cylinder gunk movb %cl, %al # max sector (and # sectors) popl %edi popl %esi popl %ebx popl %ebp ret /* # # memsize(i) : return the memory size in KB. i == 0 for conventional memory, # i == 1 for extended memory # BIOS call "INT 12H" to get conventional memory size # BIOS call "INT 15H, AH=88H" to get extended memory size # Both have the return value in AX. # */ ENTRY(memsize) pushl %ebp movl %esp, %ebp pushl %ebx pushl %esi pushl %edi movl 8(%ebp), %ebx call _C_LABEL(prot_to_real) # enter real mode testb %bl, %bl data32 jnz xext int $0x12 data32 jmp xdone xext: movb $0x88, %ah int $0x15 xdone: movl %eax, %ebx data32 call _C_LABEL(real_to_prot) movl %ebx, %eax popl %edi popl %esi popl %ebx popl %ebp ret /* # BIOS call "INT 15H Function 86H" to sleep for a set number of microseconds # Call with %ah = 0x86 # %cx = time interval (high) # %dx = time interval (low) # Return: # If error # CF = set # else # CF = clear */ ENTRY(usleep) pushl %ebp movl %esp, %ebp pushl %ebx movw 8(%ebp), %dx movw 10(%ebp), %cx call _C_LABEL(prot_to_real) movb $0x86, %ah int $0x15 setnc %ah movb %ah, %bl # real_to_prot uses %eax data32 call _C_LABEL(real_to_prot) xorl %eax, %eax movb %bl, %al popl %ebx popl %ebp ret