330 lines
6.6 KiB
ArmAsm
330 lines
6.6 KiB
ArmAsm
/* $NetBSD: bios.S,v 1.6 1994/10/27 04:14:31 cgd 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.
|
|
*/
|
|
|
|
.file "bios.s"
|
|
|
|
#include "asm.h"
|
|
.text
|
|
|
|
/*
|
|
# biosread(dev, cyl, head, sec, nsec, offset)
|
|
# Read "nsec" sectors from disk to offset "offset" in boot segment
|
|
# 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 %ecx
|
|
pushl %edx
|
|
pushl %es
|
|
|
|
movb 0x10(%ebp), %dh
|
|
movw 0x0c(%ebp), %cx
|
|
xchgb %ch, %cl # cylinder; the highest 2 bits of cyl is in %cl
|
|
rorb $2, %cl
|
|
movb 0x14(%ebp), %al
|
|
orb %al, %cl
|
|
incb %cl # sector; sec starts from 1, not 0
|
|
movb 0x8(%ebp), %dl # device
|
|
movl 0x1c(%ebp), %ebx # offset
|
|
# prot_to_real will set %es to BOOTSEG
|
|
|
|
call EXT(prot_to_real) # enter real mode
|
|
movb $0x2, %ah # subfunction
|
|
addr32
|
|
movb 0x18(%ebp), %al # number of sectors
|
|
|
|
sti
|
|
int $0x13
|
|
cli
|
|
|
|
movl %eax, %ebx # save return value (actually movw %ax, %bx)
|
|
|
|
data32
|
|
call EXT(real_to_prot) # back to protected mode
|
|
|
|
xorl %eax, %eax
|
|
movb %bh, %al # return value in %ax
|
|
|
|
popl %es
|
|
popl %edx
|
|
popl %ecx
|
|
popl %ebx
|
|
popl %ebp
|
|
|
|
ret
|
|
|
|
|
|
/*
|
|
# putc(ch)
|
|
# BIOS call "INT 10H Function 0Eh" to write character to console
|
|
# Call with %ah = 0x0e
|
|
# %al = character
|
|
# %bh = page
|
|
# %bl = foreground color ( graphics modes)
|
|
*/
|
|
|
|
|
|
ENTRY(putc)
|
|
pushl %ebp
|
|
movl %esp, %ebp
|
|
pushl %ebx
|
|
pushl %ecx
|
|
|
|
movb 0x8(%ebp), %cl
|
|
|
|
call EXT(prot_to_real)
|
|
|
|
data32
|
|
movl $0x1, %ebx # %bh=0, %bl=1 (blue)
|
|
movb $0xe, %ah
|
|
movb %cl, %al
|
|
sti
|
|
int $0x10 # display a byte
|
|
cli
|
|
|
|
data32
|
|
call EXT(real_to_prot)
|
|
|
|
popl %ecx
|
|
popl %ebx
|
|
popl %ebp
|
|
ret
|
|
|
|
|
|
/*
|
|
# getc()
|
|
# BIOS call "INT 16H Function 00H" to read character from keyboard
|
|
# Call with %ah = 0x0
|
|
# Return: %ah = keyboard scan code
|
|
# %al = ASCII character
|
|
*/
|
|
|
|
ENTRY(getc)
|
|
pushl %ebp
|
|
movl %esp, %ebp
|
|
pushl %ebx # save %ebx
|
|
|
|
call EXT(prot_to_real)
|
|
|
|
movb $0x0, %ah
|
|
sti
|
|
int $0x16
|
|
cli
|
|
|
|
movb %al, %bl # real_to_prot uses %eax
|
|
|
|
data32
|
|
call EXT(real_to_prot)
|
|
|
|
xorl %eax, %eax
|
|
movb %bl, %al
|
|
|
|
popl %ebx
|
|
popl %ebp
|
|
ret
|
|
/*
|
|
# ischar()
|
|
# if there is a character pending, return it; otherwise return 0
|
|
# BIOS call "INT 16H Function 01H" to check whether a character is pending
|
|
# Call with %ah = 0x1
|
|
# Return:
|
|
# If key waiting to be input:
|
|
# %ah = keyboard scan code
|
|
# %al = ASCII character
|
|
# Zero flag = clear
|
|
# else
|
|
# Zero flag = set
|
|
*/
|
|
ENTRY(ischar)
|
|
pushl %ebp
|
|
movl %esp, %ebp
|
|
pushl %ebx
|
|
|
|
call EXT(prot_to_real) # enter real mode
|
|
|
|
xorl %ebx, %ebx
|
|
movb $0x1, %ah
|
|
sti
|
|
int $0x16
|
|
cli
|
|
data32
|
|
jz nochar
|
|
movb %al, %bl
|
|
|
|
nochar:
|
|
data32
|
|
call EXT(real_to_prot)
|
|
|
|
xorl %eax, %eax
|
|
movb %bl, %al
|
|
|
|
popl %ebx
|
|
popl %ebp
|
|
ret
|
|
|
|
/*
|
|
#
|
|
# 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 %es
|
|
pushl %ebx
|
|
pushl %ecx
|
|
pushl %edx
|
|
|
|
movb 0x8(%ebp), %dl # diskinfo(drive #)
|
|
call EXT(prot_to_real) # enter real mode
|
|
|
|
movb $0x8, %ah # ask for disk info
|
|
|
|
sti
|
|
int $0x13
|
|
cli
|
|
|
|
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 EXT(real_to_prot) # back to protected mode
|
|
|
|
xor %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 %edx
|
|
popl %ecx
|
|
popl %ebx
|
|
popl %es
|
|
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
|
|
|
|
movl 8(%ebp), %ebx
|
|
|
|
call EXT(prot_to_real) # enter real mode
|
|
|
|
testb %bl, %bl
|
|
data32
|
|
jnz xext
|
|
|
|
sti
|
|
int $0x12
|
|
cli
|
|
data32
|
|
jmp xdone
|
|
|
|
xext: movb $0x88, %ah
|
|
sti
|
|
int $0x15
|
|
cli
|
|
|
|
xdone:
|
|
movl %eax, %ebx
|
|
|
|
data32
|
|
call EXT(real_to_prot)
|
|
|
|
movl %ebx, %eax
|
|
popl %ebx
|
|
popl %ebp
|
|
ret
|