mirror of https://github.com/dzavalishin/oskit/
83 lines
2.4 KiB
ArmAsm
Executable File
83 lines
2.4 KiB
ArmAsm
Executable File
/*
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* Copyright (c) 1995-1997 University of Utah and the Flux Group.
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*
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* This file is part of the OSKit Linux Boot Loader, which is free software,
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* also known as "open source;" you can redistribute it and/or modify it under
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* the terms of the GNU General Public License (GPL), version 2, as published
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* by the Free Software Foundation (FSF).
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*
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* The OSKit is distributed in the hope that it will be useful, but WITHOUT ANY
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* WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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* FOR A PARTICULAR PURPOSE. See the GPL for more details. You should have
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* received a copy of the GPL along with the OSKit; see the file COPYING. If
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* not, write to the FSF, 59 Temple Place #330, Boston, MA 02111-1307, USA.
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*/
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#include <oskit/x86/asm.h>
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/* NOTE! These had better be the same as in bootsect.s! */
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#include <linux/config.h>
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#define INITSEG DEF_INITSEG /* we move boot here - out of the way */
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#define SYSSEG DEF_SYSSEG /* system loaded at 0x10000 (65536). */
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#define SETUPSEG DEF_SETUPSEG /* this is the current segment */
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#define HIGHSECS 5 /* nr of sectors loaded at INITSEG */
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#define STACK_SIZE 4096
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.text
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.code16
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/*
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* Entrypoint from Linux boot loaders such as LILO.
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*
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* Note that whereas in the Linux 16-bit boot code,
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* the 'bootsect' and 'setup' fragments are compiled and linked separately,
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* in this code they are linked into one big small-model binary image.
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* This means that, whereas the Linux setup code expects to run at 9020:0000,
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* this setup code wants to run at 9000:0200.
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* Since LILO and other Linux boot loaders will be starting us at 9020:0000,
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* we need to fix the CS and EIP early on to conform to our environment.
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* That's what the ljmp instruction below is for.
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*/
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setup_entry:
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cli
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cld
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/* Move the rest of the linuxboot code and data up from SYSSEG. */
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movw $SYSSEG,%ax
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movw %ax,%ds
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movw $INITSEG,%ax
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movw %ax,%es
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xorw %si,%si
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movw $HIGHSECS*512,%di
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movl $EXT(edata)-HIGHSECS*512,%ecx
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rep
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movsb
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/* Jump to the segment we want to be running in. */
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ljmp $INITSEG,$0f
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0:
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movw %ax,%ds
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/* Switch to a stack in the same segment as everything else. */
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movw %ax,%ss
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movl $stack+STACK_SIZE,%esp
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.comm stack,STACK_SIZE
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/* Clear our BSS segment. */
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movl $EXT(edata),%edi
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movl $EXT(end),%ecx
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subw %di,%cx
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xorb %al,%al
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cld
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rep
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stosb
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/* Make backtraces terminate */
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xorl %ebp,%ebp
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jmp EXT(i16_bios_main)
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