279 lines
5.8 KiB
ArmAsm
279 lines
5.8 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 11:34:13 rpd
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* $Id$
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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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.file "asm.s"
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#include "asm.h"
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CR0_PE_ON = 0x1
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CR0_PE_OFF = 0xfffffffe
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.text
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/*
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*
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* real_to_prot()
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* transfer from real mode to protected mode.
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*/
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ENTRY(real_to_prot)
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/* guarantee that interrupt is disabled when in prot mode */
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cli
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/* load the gdtr */
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addr32
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data32
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lgdt EXT(Gdtr)
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/* set the PE bit of CR0 */
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mov %cr0, %eax
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data32
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or $CR0_PE_ON, %eax
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mov %eax, %cr0
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/*
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* make intrasegment jump to flush the processor pipeline and
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* reload CS register
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*/
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data32
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ljmp $0x18, $xprot
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xprot:
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/*
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* we are in USE32 mode now
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* set up the protected mode segment registers : DS, SS, ES, FS
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*/
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movw $0x20, %ax /* data segment */
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mov %ax, %ds /* gas would waste a prefix byte for movw */
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mov %ax, %ss
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mov %ax, %es
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movw $0x10, %ax /* flat segment */
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mov %ax, %fs
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#ifdef BDE_DEBUGGER
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/* load idtr so we can debug */
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lidt EXT(Idtr_prot)
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#endif
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ret
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/*
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*
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* prot_to_real()
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* transfer from protected mode to real mode
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*
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*/
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ENTRY(prot_to_real)
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/* Prepare %ax while we're still in a mode that gas understands. */
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movw $0x30, %ax
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/* Change to use16 mode. */
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ljmp $0x28, $x16
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x16:
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mov %ax, %ds
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mov %ax, %ss
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mov %ax, %es
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mov %ax, %fs
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/* clear the PE bit of CR0 */
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mov %cr0, %eax
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data32
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and $CR0_PE_OFF, %eax
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mov %eax, %cr0
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/*
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* make intersegment jmp to flush the processor pipeline
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* and reload CS register
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*/
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data32
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ljmp $BOOTSEG, $xreal
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xreal:
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/*
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* we are in real mode now
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* set up the real mode segment registers : DS, SS, ES, FS
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*/
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mov %cs, %ax
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mov %ax, %ds
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mov %ax, %ss
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mov %ax, %es
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mov %ax, %fs
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#ifdef BDE_DEBUGGER
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/* load idtr so we can debug */
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addr32
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data32
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lidt EXT(Idtr_real)
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#endif
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data32
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ret
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/*
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* startprog(phyaddr)
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* start the program on protected mode where phyaddr is the entry point
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*
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* XXX This whole mess should go away and we should run the boot code in
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* flat 32 bit mode with it linked -T BOOTSEG. See the netboot code for
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* how this is done.
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*/
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ENTRY(startprog)
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push %ebp
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mov %esp, %ebp
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movl %esp, %eax /* Use eax as the old stack pointer */
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/* convert the current stack to a 32 bit flat model */
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movw $0x10, %bx
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mov %bx, %ss
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addl $(BOOTSEG<<4),%esp
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/* copy the arguments from the old stack to the new stack */
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pushl 0x14(%eax) /* &bootinfo */
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pushl $0 /* was &nfsdiskless */
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pushl $0 /* was esym */
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pushl $0 /* was cyloffset */
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pushl 0x10(%eax) /* bootdev */
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pushl 0x0C(%eax) /* howto */
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movl $(ourreturn),%ebx
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addl $(BOOTSEG<<4),%ebx /* Fix it up for flat segments */
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pushl %ebx /* our return address */
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/* push on our entry address */
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pushl $0x08 /* segment selector */
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pushl 0x08(%eax) /* kernel entry address */
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/* convert over the other data segs */
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movw $0x10, %bx
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mov %bx, %ds
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mov %bx, %es
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/* convert the PC (and code seg) */
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lret
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ourreturn:
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/* For now there is not much we can do, just lock in a loop */
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jmp ourreturn
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/*
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*
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* pbzero( dst, cnt)
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* where src is a virtual address and dst is a physical address
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*/
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ENTRY(pbzero)
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push %ebp
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mov %esp, %ebp
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push %es
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push %esi
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push %edi
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push %ecx
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cld
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/* set %es to point at the flat segment */
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movw $0x10, %ax
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mov %ax, %es
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mov 0x8(%ebp), %edi /* destination */
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mov 0xc(%ebp), %ecx /* count */
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xorl %eax, %eax /* value 0 */
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rep
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stosb
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pop %ecx
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pop %edi
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pop %esi
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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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* pcpy(src, dst, cnt)
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* where src is a virtual address and dst is a physical address
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*/
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ENTRY(pcpy)
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push %ebp
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mov %esp, %ebp
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push %es
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push %esi
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push %edi
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push %ecx
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cld
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/* set %es to point at the flat segment */
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movw $0x10, %ax
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mov %ax, %es
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mov 0x8(%ebp), %esi /* source */
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mov 0xc(%ebp), %edi /* destination */
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mov 0x10(%ebp), %ecx /* count */
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rep
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movsb
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pop %ecx
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pop %edi
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pop %esi
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pop %es
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pop %ebp
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ret
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