freebsd-dev/sys/pc98/boot/biosboot/bios.S
Satoshi Asami 4c7278c696 The PC98-specific files.
Ok'd by:	core
Submitted by:	FreeBSD(98) development team
1996-06-14 10:04:54 +00:00

314 lines
6.4 KiB
ArmAsm

/*
* 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 11:34:26 rpd
* $Id: bios.S,v 1.5 1995/09/03 05:36:13 julian 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
*/
.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 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:
* %al = 0x0 on success; err code on failure
*/
ENTRY(biosread)
push %ebp
mov %esp, %ebp
push %ebx
push %ecx
push %edx
push %es
movb 0x14(%ebp), %dl /* sector */
movb 0x10(%ebp), %dh /* head */
movw 0x0c(%ebp), %cx /* cylinder */
movb 0x08(%ebp), %al /* DA/UA */
movb $0x06, %ah
andb $0xf0, %al
cmpb $0x90, %al
jnz 1f
incb %dl
movb $0x02, %ch
movb $0xd6, %ah
1:
movb 0x08(%ebp), %al
movl %eax, %ebx
/* prot_to_real will set %es to BOOTSEG */
call EXT(prot_to_real) /* enter real mode */
mov %ebx, %eax
xor %ebx, %ebx
addr32
movb 0x18(%ebp), %bl /* number of sectors */
data32
shl $9, %ebx
data32
push %ebx
addr32
data32
mov 0x1c(%ebp), %ebx
data32
mov %ebx, %ebp
data32
pop %ebx
int $0x1b
jc 1f
xor %eax, %eax
1:
/* save return value (actually movw %ax, %bx) */
mov %eax, %ebx
data32
call EXT(real_to_prot) /* back to protected mode */
xor %eax, %eax
movb %bh, %al /* return value in %ax */
pop %es
pop %edx
pop %ecx
pop %ebx
pop %ebp
ret
/*
* getc()
* BIOS call "INT 18H Function 00H" to read character from keyboard
* Call with %ah = 0x0
* Return: %ah = keyboard scan code
* %al = ASCII character
*/
ENTRY(getc)
push %ebp
mov %esp, %ebp
push %ebx /* save %ebx */
call EXT(prot_to_real)
movb $0x0, %ah
int $0x18
movb %al, %bl /* real_to_prot uses %eax */
data32
call EXT(real_to_prot)
xor %eax, %eax
movb %bl, %al
pop %ebx
pop %ebp
ret
/*
* ischar()
* if there is a character pending, return it; otherwise return 0
* BIOS call "INT 18H 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
* %bh = 1
* else
* %bh = 0
*/
ENTRY(ischar)
push %ebp
mov %esp, %ebp
push %ebx
call EXT(prot_to_real) /* enter real mode */
xor %ebx, %ebx
movb $0x1, %ah
int $0x18
andb %bh, %bh
data32
jz nochar
movb %al, %bl
nochar:
data32
call EXT(real_to_prot)
xor %eax, %eax
movb %bl, %al
pop %ebx
pop %ebp
ret
/*
*
* get_diskinfo(): return a word that represents the
* max number of sectors and heads and drives for this device
*
*/
ENTRY(get_diskinfo)
push %ebp
mov %esp, %ebp
push %es
push %ebx
push %ecx
push %edx
movb 0x8(%ebp), %dl /* diskinfo(drive #) */
call EXT(prot_to_real) /* enter real mode */
movb %dl, %al /* ask for disk info */
andb $0xf0, %al
cmpb $0x90, %al
jz fdd
movb %dl, %al
movb $0x84, %ah
int $0x1b
jnc ok
/*
* Urk. Call failed. It is not supported for floppies by old BIOS's.
* Guess it's a 15-sector floppy.
*/
fdd:
subb %ah, %ah /* %ax = 0 */
movb %al, %al
movb %ah, %bh /* %bh = 0 */
movb $2, %bl /* %bl bits 0-3 = drive type,
bit 2 = 1.2M */
movb $79, %ch /* max track */
movb $1, %cl /* # floppy drives installed */
movb $2, %dh /* max head */
movb $15, %dl /* max sector */
/* es:di = parameter table */
/* carry = 0 */
ok:
data32
call EXT(real_to_prot) /* back to protected mode */
/*
* form a longword representing all this gunk:
* 16 bit cylinder
* 8 bit head
* 8 bit sector
*/
mov %ecx, %eax
sall $16,%eax /* << 16 */
movb %dh, %ah /* max head */
movb %dl, %al /* max sector (and # sectors) */
pop %edx
pop %ecx
pop %ebx
pop %es
pop %ebp
ret
/*
*
* memsize(i) : return the memory size in KB. i == 0 for conventional memory,
* i == 1 for extended memory
* Both have the return value in AX.
*
*/
ENTRY(memsize)
push %ebp
mov %esp, %ebp
push %ebx
mov 8(%ebp), %ebx
xor %eax, %eax
cmpb $0x01, %bl
jnz memcnv
memext:
movb 0x11401, %al
shll $7, %eax
xorl %ebx, %ebx
movw 0x11594, %bx
shll $10, %ebx
addl %ebx, %eax
jmp xdone
memcnv:
movb 0x11501, %al
andb $0x07, %al
incl %eax
shll $7, %eax
xdone:
pop %ebx
pop %ebp
ret