f7710986e2
be loaded above 1MB. Same boot code for floppies now. Speed improvements. etc etc etc. (I don't have much history on this, but then have been tested)
159 lines
5.7 KiB
C
159 lines
5.7 KiB
C
/*
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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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/*
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* HISTORY
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* $Log: table.c,v $
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* Revision 1.2 1993/07/11 12:02:25 andrew
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* Fixes from bde, including support for loading @ any MB boundary (e.g. a
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* kernel linked for 0xfe100000 will load at the 1MB mark) and read-ahead
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* buffering to speed booting from floppies. Also works with aha174x
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* controllers in enhanced mode.
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*
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*
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* 93/06/28 bde
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* Remove remaining magic numbers that depend on the load address.
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* IDTs and many more GDT entries to support my debugger.
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*
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* 93/06/27 bde
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* Remove unused Gdtr2.
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* Remove some magic numbers from Gdtr and Gdt. The boot loader may
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* override the ones related to the standard load address of 0x90000.
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*
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* Revision 1.1 1993/03/21 18:08:47 cgd
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* after 0.2.2 "stable" patches applied
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*
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* Revision 2.2 92/04/04 11:36:43 rpd
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* Fix Intel Copyright as per B. Davies authorization.
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* [92/04/03 rvb]
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* Taken from 2.5 bootstrap.
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* [92/03/30 rvb]
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*
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* Revision 2.2 91/04/02 14:42:22 mbj
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* Add Intel copyright
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* [90/02/09 rvb]
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*
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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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/* Segment Descriptor
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*
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* 31 24 19 16 7 0
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* ------------------------------------------------------------
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* | | |B| |A| | | |1|0|E|W|A| |
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* | BASE 31..24 |G|/|0|V| LIMIT |P|DPL| TYPE | BASE 23:16 |
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* | | |D| |L| 19..16| | |1|1|C|R|A| |
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* ------------------------------------------------------------
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* | | |
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* | BASE 15..0 | LIMIT 15..0 |
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* | | |
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* ------------------------------------------------------------
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*/
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struct seg_desc {
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unsigned short limit_15_0;
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unsigned short base_15_0;
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unsigned char base_23_16;
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unsigned char p_dpl_type;
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unsigned char g_b_a_limit;
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unsigned char base_31_24;
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};
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#define RUN 0 /* not really 0, but filled in at boot time */
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struct seg_desc Gdt[] = {
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{0x0, 0x0, 0x0, 0x0, 0x0, 0x0}, /* 0x0 : null */
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{0xFFFF, 0x0, 0x0, 0x9F, 0xCF, 0x0}, /* 0x08 : kernel code */
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/* 0x9E? */
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{0xFFFF, 0x0, 0x0, 0x93, 0xCF, 0x0}, /* 0x10 : kernel data */
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/* 0x92? */
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{0xFFFF, RUN, RUN, 0x9E, 0x40, 0x0}, /* 0x18 : boot code */
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{0xFFFF, RUN, RUN, 0x92, 0x40, 0x0}, /* 0x20 : boot data */
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{0xFFFF, RUN, RUN, 0x9E, 0x0, 0x0}, /* 0x28 : boot code, 16 bits */
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/* More for bdb. */
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{}, /* BIOS_CS_INDEX = 6 : null */
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{}, /* BIOS_TMP_INDEX = 7 : null */
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{}, /* TSS_INDEX = 8 : null */
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{0xFFFF, 0x0, 0x0, 0xB2, 0x40, 0x0}, /* DS_286_INDEX = 9 */
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{0xFFFF, 0x0, 0x0, 0xB2, 0x40, 0x0}, /* ES_286_INDEX = 10 */
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{}, /* Unused = 11 : null */
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{0x7FFF, 0x8000, 0xB, 0xB2, 0x40, 0x0}, /* COLOR_INDEX = 12 */
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{0x7FFF, 0x0, 0xB, 0xB2, 0x40, 0x0}, /* MONO_INDEX = 13 */
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{0xFFFF, RUN, RUN, 0x9A, 0x40, 0x0}, /* DB_CS_INDEX = 14 */
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{0xFFFF, RUN, RUN, 0x9A, 0x0, 0x0}, /* DB_CS16_INDEX = 15 */
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{0xFFFF, RUN, RUN, 0x92, 0x40, 0x0}, /* DB_DS_INDEX = 16 */
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{8*18-1, RUN, RUN, 0x92, 0x40, 0x0}, /* GDT_INDEX = 17 */
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};
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struct idt_desc {
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unsigned short entry_15_0;
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unsigned short selector;
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unsigned char padding;
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unsigned char p_dpl_type;
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unsigned short entry_31_16;
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};
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struct idt_desc Idt[] = {
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{}, /* Null (int 0) */
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{RUN, 0x70, 0, 0x8E, 0}, /* DEBUG_VECTOR = 1 */
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{}, /* Null (int 2) */
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{RUN, 0x70, 0, 0xEE, 0}, /* BREAKPOINT_VECTOR = 3 */
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};
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struct pseudo_desc {
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unsigned short limit;
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unsigned short base_low;
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unsigned short base_high;
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};
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struct pseudo_desc Gdtr = { sizeof Gdt - 1, RUN, RUN };
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struct pseudo_desc Idtr_prot = { sizeof Idt - 1, RUN, RUN };
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struct pseudo_desc Idtr_real = { 0x400 - 1, 0x0, 0x0 };
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