93 lines
2.2 KiB
ArmAsm
93 lines
2.2 KiB
ArmAsm
/* $OpenBSD: srt0.S,v 1.4 2022/12/08 01:25:44 guenther Exp $ */
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/*
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* Copyright (c) 1997 Michael Shalayeff
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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*/
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#include <machine/asm.h>
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#include <assym.h>
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#define BOOTSTACK 0xfffc
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.globl end
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.globl edata
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.globl boot
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.globl _rtt
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.globl bios_bootdev
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.globl pmm_init
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.globl Gdtr
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.text
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.align 16
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.code16
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.globl _start
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_start:
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popl %eax
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cmpl $BOOTMAGIC, %eax
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je 1f
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#ifdef DEBUG
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movl $0xb80a0, %ebx
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addr32 movl $0x07420742, (%ebx)
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#endif
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1:
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popl %edx
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cli
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pushl %cs
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popl %ds
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addr32 data32 lgdt (Gdtr - LINKADDR)
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movl %cr0, %eax
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orl $CR0_PE, %eax
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data32 movl %eax, %cr0
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data32 ljmp $8, $1f
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1:
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.code32
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movl $0x10,%eax
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mov %ax,%ds
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mov %ax,%ss
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mov %ax,%es
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mov %ax,%fs
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mov %ax,%gs
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movl $BOOTSTACK,%esp
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pushl %edx
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movl %edx, bios_bootdev
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/* Now do it all */
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#ifdef DEBUG
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movl $0xb80a4, %ebx
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movl $0x07520752, (%ebx)
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#endif
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/* zero .bss */
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xorl %eax, %eax
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movl $end, %ecx
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subl $edata,%ecx
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movl $edata, %edi
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cld
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rep; stosb
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call pmm_init
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call boot
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jmp _rtt
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