314 lines
6.4 KiB
ArmAsm
314 lines
6.4 KiB
ArmAsm
/*
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* Mach Operating System
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* Copyright (c) 1992, 1991 Carnegie Mellon University
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* All Rights Reserved.
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*
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* Permission to use, copy, modify and distribute this software and its
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* documentation is hereby granted, provided that both the copyright
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* notice and this permission notice appear in all copies of the
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* software, derivative works or modified versions, and any portions
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* thereof, and that both notices appear in supporting documentation.
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*
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* CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
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* CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
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* ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
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*
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* Carnegie Mellon requests users of this software to return to
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*
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* Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU
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* School of Computer Science
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* Carnegie Mellon University
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* Pittsburgh PA 15213-3890
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*
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* any improvements or extensions that they make and grant Carnegie Mellon
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* the rights to redistribute these changes.
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*
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* from: Mach, Revision 2.2 92/04/04 11:34:26 rpd
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* $Id: bios.S,v 1.5 1995/09/03 05:36:13 julian Exp $
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*/
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/*
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Copyright 1988, 1989, 1990, 1991, 1992
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by Intel Corporation, Santa Clara, California.
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All Rights Reserved
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Permission to use, copy, modify, and distribute this software and
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its documentation for any purpose and without fee is hereby
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granted, provided that the above copyright notice appears in all
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copies and that both the copyright notice and this permission notice
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appear in supporting documentation, and that the name of Intel
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not be used in advertising or publicity pertaining to distribution
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of the software without specific, written prior permission.
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INTEL DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE
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INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS,
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IN NO EVENT SHALL INTEL BE LIABLE FOR ANY SPECIAL, INDIRECT, OR
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CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
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LOSS OF USE, DATA OR PROFITS, WHETHER IN ACTION OF CONTRACT,
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NEGLIGENCE, OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
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WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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/*
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* Ported to PC-9801 by Yoshio Kimura
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*/
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.file "bios.s"
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#include "asm.h"
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.text
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/*
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* biosread(dev, cyl, head, sec, nsec, offset)
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* Read "nsec" sectors from disk to offset "offset" in boot segment
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* BIOS call "INT 0x1B Function 0xn6" to read sectors from disk into memory
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* Call with %ah = 0xd6(for floppy disk) or 0x06(for hard disk)
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* %al = DA/UA
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* %bx = data length
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* %ch = sector size(for floppy) or cylinder(for hard)
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* %cl = cylinder
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* %dh = head
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* %dl = sector
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* %es:%bp = segment:offset of buffer
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* Return:
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* %al = 0x0 on success; err code on failure
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*/
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ENTRY(biosread)
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push %ebp
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mov %esp, %ebp
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push %ebx
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push %ecx
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push %edx
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push %es
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movb 0x14(%ebp), %dl /* sector */
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movb 0x10(%ebp), %dh /* head */
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movw 0x0c(%ebp), %cx /* cylinder */
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movb 0x08(%ebp), %al /* DA/UA */
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movb $0x06, %ah
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andb $0xf0, %al
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cmpb $0x90, %al
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jnz 1f
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incb %dl
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movb $0x02, %ch
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movb $0xd6, %ah
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1:
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movb 0x08(%ebp), %al
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movl %eax, %ebx
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/* prot_to_real will set %es to BOOTSEG */
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call EXT(prot_to_real) /* enter real mode */
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mov %ebx, %eax
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xor %ebx, %ebx
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addr32
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movb 0x18(%ebp), %bl /* number of sectors */
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data32
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shl $9, %ebx
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data32
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push %ebx
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addr32
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data32
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mov 0x1c(%ebp), %ebx
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data32
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mov %ebx, %ebp
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data32
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pop %ebx
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int $0x1b
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jc 1f
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xor %eax, %eax
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1:
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/* save return value (actually movw %ax, %bx) */
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mov %eax, %ebx
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data32
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call EXT(real_to_prot) /* back to protected mode */
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xor %eax, %eax
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movb %bh, %al /* return value in %ax */
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pop %es
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pop %edx
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pop %ecx
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pop %ebx
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pop %ebp
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ret
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/*
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* getc()
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* BIOS call "INT 18H Function 00H" to read character from keyboard
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* Call with %ah = 0x0
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* Return: %ah = keyboard scan code
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* %al = ASCII character
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*/
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ENTRY(getc)
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push %ebp
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mov %esp, %ebp
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push %ebx /* save %ebx */
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call EXT(prot_to_real)
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movb $0x0, %ah
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int $0x18
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movb %al, %bl /* real_to_prot uses %eax */
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data32
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call EXT(real_to_prot)
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xor %eax, %eax
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movb %bl, %al
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pop %ebx
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pop %ebp
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ret
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/*
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* ischar()
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* if there is a character pending, return it; otherwise return 0
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* BIOS call "INT 18H Function 01H" to check whether a character is pending
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* Call with %ah = 0x1
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* Return:
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* If key waiting to be input:
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* %ah = keyboard scan code
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* %al = ASCII character
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* %bh = 1
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* else
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* %bh = 0
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*/
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ENTRY(ischar)
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push %ebp
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mov %esp, %ebp
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push %ebx
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call EXT(prot_to_real) /* enter real mode */
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xor %ebx, %ebx
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movb $0x1, %ah
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int $0x18
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andb %bh, %bh
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data32
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jz nochar
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movb %al, %bl
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nochar:
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data32
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call EXT(real_to_prot)
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xor %eax, %eax
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movb %bl, %al
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pop %ebx
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pop %ebp
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ret
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/*
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*
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* get_diskinfo(): return a word that represents the
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* max number of sectors and heads and drives for this device
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*
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*/
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ENTRY(get_diskinfo)
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push %ebp
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mov %esp, %ebp
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push %es
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push %ebx
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push %ecx
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push %edx
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movb 0x8(%ebp), %dl /* diskinfo(drive #) */
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call EXT(prot_to_real) /* enter real mode */
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movb %dl, %al /* ask for disk info */
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andb $0xf0, %al
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cmpb $0x90, %al
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jz fdd
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movb %dl, %al
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movb $0x84, %ah
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int $0x1b
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jnc ok
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/*
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* Urk. Call failed. It is not supported for floppies by old BIOS's.
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* Guess it's a 15-sector floppy.
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*/
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fdd:
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subb %ah, %ah /* %ax = 0 */
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movb %al, %al
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movb %ah, %bh /* %bh = 0 */
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movb $2, %bl /* %bl bits 0-3 = drive type,
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bit 2 = 1.2M */
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movb $79, %ch /* max track */
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movb $1, %cl /* # floppy drives installed */
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movb $2, %dh /* max head */
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movb $15, %dl /* max sector */
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/* es:di = parameter table */
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/* carry = 0 */
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ok:
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data32
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call EXT(real_to_prot) /* back to protected mode */
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/*
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* form a longword representing all this gunk:
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* 16 bit cylinder
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* 8 bit head
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* 8 bit sector
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*/
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mov %ecx, %eax
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sall $16,%eax /* << 16 */
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movb %dh, %ah /* max head */
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movb %dl, %al /* max sector (and # sectors) */
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pop %edx
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pop %ecx
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pop %ebx
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pop %es
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pop %ebp
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ret
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/*
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*
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* memsize(i) : return the memory size in KB. i == 0 for conventional memory,
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* i == 1 for extended memory
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* Both have the return value in AX.
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*
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*/
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ENTRY(memsize)
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push %ebp
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mov %esp, %ebp
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push %ebx
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mov 8(%ebp), %ebx
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xor %eax, %eax
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cmpb $0x01, %bl
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jnz memcnv
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memext:
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movb 0x11401, %al
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shll $7, %eax
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xorl %ebx, %ebx
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movw 0x11594, %bx
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shll $10, %ebx
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addl %ebx, %eax
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jmp xdone
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memcnv:
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movb 0x11501, %al
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andb $0x07, %al
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incl %eax
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shll $7, %eax
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xdone:
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pop %ebx
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pop %ebp
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ret
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