173 lines
3.8 KiB
ArmAsm
173 lines
3.8 KiB
ArmAsm
/*
|
|
* Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
|
|
*
|
|
* 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.
|
|
*/
|
|
|
|
#include "asm.h"
|
|
|
|
/* Conventional GDT indexes. */
|
|
#define BOOT_CS_INDEX 3
|
|
#define BOOT_CS16_INDEX 5
|
|
#define BOOT_DS_INDEX 4
|
|
#define DB_CS_INDEX 14
|
|
#define DB_CS16_INDEX 15
|
|
#define DB_DS_INDEX 16
|
|
#define GDT_INDEX 17
|
|
|
|
/* Vector numbers. */
|
|
#define BREAKPOINT_VECTOR 3
|
|
#define DEBUG_VECTOR 1
|
|
|
|
/*
|
|
* boot2() -- second stage boot
|
|
*/
|
|
|
|
.globl EXT(ouraddr)
|
|
|
|
ENTRY(boot2)
|
|
data32
|
|
subl %eax, %eax
|
|
mov %cs, %ax
|
|
mov %ax, %ds
|
|
mov %ax, %es
|
|
data32
|
|
shll $4, %eax
|
|
addr32
|
|
data32
|
|
movl %eax, EXT(ouraddr)
|
|
|
|
/* 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 entry for GDT, and GDT and IDT pointers */
|
|
data32
|
|
movl %eax, %ecx
|
|
data32
|
|
addl $ EXT(Gdt), %eax
|
|
data32
|
|
shld $16, %eax, %ebx
|
|
FIXUP(GDT_INDEX)
|
|
addr32
|
|
data32
|
|
movl %eax, EXT(Gdtr)+2
|
|
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
|
|
|
|
#ifdef BDB
|
|
/* 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
|
|
|
|
/* XXX appears to be broken */
|
|
/* fix up IDT entries for bdb */
|
|
subl $2, %ebx
|
|
movl %es:(%edi), %eax /* actually movw %es:(%bx), %ax */
|
|
addr32
|
|
movl %eax, EXT(Idt)+8*DEBUG_VECTOR /* actually movw %ax */
|
|
movl %ecx, %ebx
|
|
subl $2, %ebx
|
|
movl %es:(%edi), %eax /* actually movw %es:(%bx), %ax */
|
|
addr32
|
|
movl %eax, EXT(Idt)+8*BREAKPOINT_VECTOR /* actually movw %ax */
|
|
#endif
|
|
|
|
/* finished with groping in real mode segments */
|
|
pop %es
|
|
|
|
/* 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
|
|
|
|
movzbl %dl, %edx /* discard head (%dh) and random high bits */
|
|
pushl %edx
|
|
call EXT(boot)
|
|
oops:
|
|
hlt
|
|
jmp oops
|
|
|
|
.data
|
|
.align 2
|
|
#if 0 /* XXX this would give losing "_ouraddr :". Better declared in C */
|
|
EXT(ouraddr):
|
|
#else
|
|
_ouraddr:
|
|
#endif
|
|
.long 0
|