191 lines
4.6 KiB
ArmAsm
191 lines
4.6 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 11:34:13 rpd
|
|
* $Id: real_prot.S,v 1.1 1994/10/01 02:55:51 davidg 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.
|
|
*/
|
|
|
|
/*
|
|
* LP (Laptop Package)
|
|
*
|
|
* Copyright (C) 1994 by HOSOKAWA, Tatsumi <hosokawa@mt.cs.keio.ac.jp>
|
|
*
|
|
* This software may be used, modified, copied, and distributed, in
|
|
* both source and binary form provided that the above copyright and
|
|
* these terms are retained. Under no circumstances is the author
|
|
* responsible for the proper functioning of this software, nor does
|
|
* the author assume any responsibility for damages incurred with its
|
|
* use.
|
|
*
|
|
* Sep., 1994 Implemented on FreeBSD 1.1.5.1R (Toshiba AVS001WD)
|
|
*/
|
|
|
|
/*
|
|
* Modified for APM BIOS initializer by HOSOKAWA Tatsumi
|
|
*
|
|
* See also locore.s.
|
|
* (This file is based directly on /sys/i386/boot/biosboot/asm.S)
|
|
*/
|
|
|
|
.file "real_prot.S"
|
|
|
|
#include "real_prot.h"
|
|
#include "apm_segments.h"
|
|
#include "apm_bios.h"
|
|
|
|
CR0_PE_ON = 0x1
|
|
CR0_PE_OFF = 0xfffffffe
|
|
|
|
.text
|
|
|
|
/*
|
|
*
|
|
* real_to_prot()
|
|
* transfer from real mode to protected mode.
|
|
*/
|
|
|
|
ENTRY(real_to_prot)
|
|
/* guarantee that interrupt is disabled when in prot mode */
|
|
cli
|
|
|
|
/*
|
|
* deleted for APM initializer by HOSOKAWA Tatsumi
|
|
* <hosoakwa@mt.cs.keio.ac.jp>
|
|
*/
|
|
#if 0
|
|
/* load the gdtr */
|
|
addr32
|
|
data32
|
|
lgdt EXT(Gdtr)
|
|
#endif
|
|
|
|
/* set the PE bit of CR0 */
|
|
mov %cr0, %eax
|
|
|
|
data32
|
|
or $CR0_PE_ON, %eax
|
|
mov %eax, %cr0
|
|
|
|
/*
|
|
* make intrasegment jump to flush the processor pipeline and
|
|
* reload CS register
|
|
*/
|
|
data32
|
|
ljmp $(APM_INIT_CS_SEL), $xprot
|
|
xprot:
|
|
|
|
/*
|
|
* we are in USE32 mode now
|
|
* set up the protected mode segment registers : DS, SS, ES
|
|
*/
|
|
movw $(APM_INIT_DS_SEL), %ax /* data segment */
|
|
mov %ax, %ds /* gas would waste a prefix byte for movw */
|
|
mov %ax, %ss
|
|
mov %ax, %es
|
|
|
|
#ifdef BDE_DEBUGGER
|
|
/* load idtr so we can debug */
|
|
lidt EXT(Idtr_prot)
|
|
#endif
|
|
|
|
ret
|
|
|
|
/*
|
|
*
|
|
* prot_to_real()
|
|
* transfer from protected mode to real mode
|
|
*
|
|
*/
|
|
|
|
ENTRY(prot_to_real)
|
|
|
|
/* Prepare %ax while we're still in a mode that gas understands. */
|
|
movw $(APM_INIT_DS16_SEL), %ax
|
|
|
|
/* Change to use16 mode. */
|
|
ljmp $(APM_INIT_CS16_SEL), $x16
|
|
x16:
|
|
|
|
mov %ax, %ds
|
|
mov %ax, %ss
|
|
mov %ax, %es
|
|
|
|
/* clear the PE bit of CR0 */
|
|
mov %cr0, %eax
|
|
data32
|
|
and $CR0_PE_OFF, %eax
|
|
mov %eax, %cr0
|
|
|
|
/*
|
|
* make intersegment jmp to flush the processor pipeline
|
|
* and reload CS register
|
|
*/
|
|
data32
|
|
ljmp $(APM_OURADDR>>4), $xreal
|
|
xreal:
|
|
|
|
/*
|
|
* we are in real mode now
|
|
* set up the real mode segment registers : DS, SS, ES
|
|
*/
|
|
mov %cs, %ax
|
|
mov %ax, %ds
|
|
mov %ax, %ss
|
|
mov %ax, %es
|
|
|
|
#ifdef BDE_DEBUGGER
|
|
/* load idtr so we can debug */
|
|
addr32
|
|
data32
|
|
lidt EXT(Idtr_real)
|
|
#endif
|
|
|
|
data32
|
|
ret
|