107 lines
2.4 KiB
ArmAsm
107 lines
2.4 KiB
ArmAsm
/*
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* Ported to boot 386BSD by Julian Elischer (julian@tfs.com) Sept 1992
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*
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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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#include "asm.h"
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/* Conventional GDT indexes. */
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#define BOOT_CS_INDEX 3
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#define BOOT_CS16_INDEX 5
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#define BOOT_DS_INDEX 4
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/* Vector numbers. */
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#define BREAKPOINT_VECTOR 3
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#define DEBUG_VECTOR 1
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/*
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* boot2() -- second stage boot
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*/
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.globl EXT(ouraddr)
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ENTRY(boot2)
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data32
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subl %eax, %eax
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movl %cs, %ax
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movl %ax, %ds
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movl %ax, %es
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data32
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shll $4, %eax
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addr32
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data32
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movl %eax, EXT(ouraddr)
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/* fix up GDT entries for bootstrap */
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#define FIXUP(gdt_index) \
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addr32; \
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movl %eax, EXT(Gdt)+(8*gdt_index)+2; /* actually movw %ax */ \
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addr32; \
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movb %bl, EXT(Gdt)+(8*gdt_index)+4
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data32
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shldl $16, %eax, %ebx
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FIXUP(BOOT_CS_INDEX)
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FIXUP(BOOT_CS16_INDEX)
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FIXUP(BOOT_DS_INDEX)
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/* fix up GDT pointer */
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data32
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movl %eax, %ecx
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data32
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addl $ EXT(Gdt), %eax
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addr32
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data32
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movl %eax, EXT(Gdtr)+2
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/* change to protected mode */
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data32
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call EXT(real_to_prot)
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/* clear the bss */
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movl $ EXT(edata), %edi /* no EXT(_edata) - krufty ld */
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movl $ EXT(end), %ecx /* or EXT(_end) */
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subl %edi, %ecx
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subb %al, %al
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rep
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stosb
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movzbl %dl, %edx /* discard head (%dh) and random high bits */
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pushl %edx
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call EXT(boot)
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oops:
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cli
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hlt
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.data
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.align 2
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#if 0 /* XXX this would give losing "_ouraddr :". Better declared in C */
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EXT(ouraddr):
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#else
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_ouraddr:
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#endif
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.long 0
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