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/*
* 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 11:35:26 rpd
* $FreeBSD$
*/
#include "asm.h"
/* Conventional GDT indexes. */
#define BOOT_CS_INDEX 3
#define BOOT_CS16_INDEX 5
#define BOOT_DS_INDEX 4
#ifdef BDE_DEBUGGER
#define DB_CS_INDEX 14
#define DB_CS16_INDEX 15
#define DB_DS_INDEX 16
#define GDT_INDEX 17
#endif
/* Vector numbers. */
#define BREAKPOINT_VECTOR 3
#define DEBUG_VECTOR 1
/*
* boot2() -- second stage boot
* SP points to default string if found
*/
ENTRY(boot2)
data32
subl %eax, %eax
mov %cs, %ax
mov %ax, %ds
mov %ax, %es
data32
shll $4, %eax
/* fix up GDT entries for bootstrap */
#define FIXUP(gdt_index) \
addr32; \
movl %eax, EXT(Gdt)+(8*gdt_index)+2; /* actually movw %ax */ \
addr32; \
movb %bl, EXT(Gdt)+(8*gdt_index)+4
data32
shld $16, %eax, %ebx
FIXUP(BOOT_CS_INDEX)
FIXUP(BOOT_CS16_INDEX)
FIXUP(BOOT_DS_INDEX)
/* fix up GDT pointer */
data32
movl %eax, %ecx
data32
addl $ EXT(Gdt), %eax
addr32
data32
movl %eax, EXT(Gdtr)+2
#ifdef BDE_DEBUGGER
/* fix up GDT entry for GDT */
data32
shld $16, %eax, %ebx
FIXUP(GDT_INDEX)
/* fix up IDT pointer */
data32
addl $ EXT(Idt), %ecx
addr32
data32
movl %ecx, EXT(Idtr_prot)+2
/* %es = vector table segment for a while */
push %es
data32
subl %eax, %eax
mov %ax, %es
/* fix up GDT entries for bdb */
data32
movl $4*DEBUG_VECTOR, %esi
addr32
movl %es: 2(%esi), %eax /* actually movw to %ax */
data32
shll $4, %eax
data32
shld $16, %eax, %ebx
FIXUP(DB_CS_INDEX)
FIXUP(DB_CS16_INDEX)
FIXUP(DB_DS_INDEX)
/* Fetch entry points of bdb's protected mode trap handlers. These
* are stored at 2 before the corresponding entry points for real mode.
*/
data32
subl %ebx, %ebx
addr32
movl %es: (%esi), %ebx /* actually movw to %bx */
data32
subl %ecx, %ecx
addr32
movl %es: 4*(BREAKPOINT_VECTOR-DEBUG_VECTOR)(%esi), %ecx
/* actually movw to %cx */
/* %es = bdb segment for a while */
data32
shrl $4, %eax
mov %ax, %es
/* fix up IDT entries for bdb */
data32
subl $2, %ebx /* calculate EA to check it */
jb 1f /* give up if it would trap */
addr32
movl %es: (%ebx), %eax /* actually movw to %ax */
addr32
movl %eax, EXT(Idt)+8*DEBUG_VECTOR /* actually movw %ax */
1:
data32
subl $2, %ecx
jb 1f
addr32
movl %es: (%ecx), %eax /* actually movw to %ax */
addr32
movl %eax, EXT(Idt)+8*BREAKPOINT_VECTOR /* actually movw %ax */
1:
/* finished with groping in real mode segments */
pop %es
#endif /* BDE_DEBUGGER */
/* change to protected mode */
data32
call EXT(real_to_prot)
/* clear the bss */
movl $ EXT(edata), %edi /* no EXT(_edata) - krufty ld */
movl $ EXT(end), %ecx /* or EXT(_end) */
subl %edi, %ecx
subb %al, %al
rep
stosb
#ifdef NAMEBLOCK
movl %esp, EXT(dflt_name)
#endif
movzbl %dl, %edx /* discard head (%dh) and random high bits */
pushl %edx
call EXT(boot)
oops:
hlt
jmp oops
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