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/*
* Erik Arjan Hendriks <hendriks@lanl.gov>
* Copyright (C) 2000 Scyld.
* Copyright (C) 2000 Scyld Computing Corporation
* Copyright (C) 2001 University of California. LA-CC Number 01-67.
* Copyright (C) 2005 Nick.Barker9@btinternet.com
* Copyright (C) 2007 coresystems GmbH
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
*/
/* Declare a temporary global descriptor table -
* necessary because the core part of the bios
* no longer sets up any 16 bit segments
*/
__asm__ (
/* pointer to original gdt */
" .globl gdtarg\n"
"gdtarg: \n"
" .word gdt_limit \n"
" .long gdtptr \n"
/* compute the table limit */
"__mygdt_limit = __mygdt_end - __mygdt - 1 \n"
" .globl __mygdtaddr\n"
"__mygdtaddr: \n"
" .word __mygdt_limit \n"
" .long __mygdt \n"
" .globl __mygdt\n"
"__mygdt: \n"
/* selgdt 0, unused */
" .word 0x0000, 0x0000 \n"
" .byte 0x00, 0x00, 0x00, 0x00 \n"
/* selgdt 8, unused */
" .word 0x0000, 0x0000 \n"
" .byte 0x00, 0x00, 0x00, 0x00 \n"
/* selgdt 0x10, flat code segment */
" .word 0xffff, 0x0000 \n"
" .byte 0x00, 0x9b, 0xcf, 0x00 \n"
/* selgdt 0x18, flat data segment */
" .word 0xffff, 0x0000 \n"
" .byte 0x00, 0x93, 0xcf, 0x00 \n"
/* selgdt 0x20, unused */
" .word 0x0000, 0x0000 \n"
" .byte 0x00, 0x00, 0x00, 0x00 \n"
/* selgdt 0x28 16-bit 64k code at 0x00000000 */
" .word 0xffff, 0x0000 \n"
" .byte 0, 0x9a, 0, 0 \n"
/* selgdt 0x30 16-bit 64k data at 0x00000000 */
" .word 0xffff, 0x0000 \n"
" .byte 0, 0x92, 0, 0 \n"
"__mygdt_end: \n"
/* FIXME: This does probably not belong here */
" .globl idtarg\n"
"idtarg:\n"
" .word _idt_end - _idt - 1\n" /* limit */
" .long _idt\n"
" .word 0\n"
"_idt:\n"
" .fill 20, 8, 0\n" // # idt is unitiailzed
"_idt_end:\n"
/* Declare a pointer to where our idt is going to be i.e. at mem zero */
" .globl __myidt\n"
"__myidt: \n"
/* 16-bit limit */
" .word 1023 \n"
/* 24-bit base */
" .long 0 \n"
" .word 0 \n"
);
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