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/* -----------------------------------------------------------------------
*
* Copyright 2003-2009 H. Peter Anvin - All Rights Reserved
* Copyright 2009 Intel Corporation; author: H. Peter Anvin
*
* 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, Inc., 51 Franklin St, Fifth Floor,
* Boston MA 02110-1301, USA; either version 2 of the License, or
* (at your option) any later version; incorporated herein by reference.
*
* ----------------------------------------------------------------------- */
/*
* Simple stub to get us to the right point in the 32-bit code;
* this module must be linked first
*/
.section ".init", "ax"
.globl _start
_start:
/* Zero the bss */
cld
movl $__bss_start, %edi
movl $__bss_end, %ecx
subl %edi, %ecx
xorl %eax, %eax
shrl $2, %ecx
rep ; stosl
/* Set up the protected-mode IDT and the interrupt jump buffers */
movl $idt, %edi
movl $ijb, %eax
movl $0xee000000, %ebx /* Interrupt gate */
movw %cs, %bx /* Target segment */
/* Make the IDT */
movl $256, %ecx
1:
stosl
stosl
movl %ebx, -6(%edi)
addl $8, %eax
loop 1b
/*
* Each entry in the interrupt jump buffer contains the following
* instructions:
*
* 60 pushal
* b0xx movb $xx, %al # interrupt number
* e9xxxxxxxx jmp handle_interrupt
*/
movl $0xe900b060, %eax
movl $256, %ecx
1:
movl %eax, (%edi)
addl $(1 << 16), %eax
movl $handle_interrupt-8, %edx
subl %edi, %edx
movl %edx, 4(%edi)
addl $8, %edi
loop 1b
lidtl idt_ptr
/* Save arguments, switch stacks */
movl %esp, %eax /* Pointer to arguments */
movl $__stack_end, %esp
call setup
jmp *(rm_args) /* First argument is return */
.section ".text","ax"
.globl intcall
.type intcall, @function
intcall:
jmp *(rm_args+1*4) /* Intcall is argument 1 */
.size intcall, .-intcall
.type handle_interrupt, @function
handle_interrupt:
jmp *(rm_args+4*4) /* Interrupt pointer is argument 4 */
.size handle_interrupt, .-handle_interrupt
.section ".rodata","a"
idt_ptr:
.word 8*256-1
.long idt
.word 0
.section ".bss.large","aw"
.balign 2048
idt:
.space 8*256
ijb:
.space 8*256
__stack:
.space 65536
__stack_end:
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