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.section .stack, "aw", @nobits
.global k_stack
.align 16 /* Stack on x86 must be 16-byte aligned according to System V ABI */
k_stack_bottom:
.skip 16 * 1024 /* 16 kByte */
k_stack:
.section .pages, "aw", @nobits
.align 4096
.global k_pagedir
k_pagedir: .skip 1024 * 4
.global k_ptable0x300
k_ptable0x300: .skip 1024 * 4
.section .text
.global k_init
.extern kmain
.extern pic_init
.extern gdt_install
.extern idt_install
k_init:
# kernel entry point, higher half
# unmap the identity mapping as its no longer necessary
movl $0, k_pagedir + 0 * 4
mov %cr3, %ecx # reload cr3 to force a TLB flush
mov %ecx, %cr3
# zero out the stack
mov $4096, %ecx # loop counter
mov $k_stack_bottom, %edi # start from the bottom
xor %edx, %edx # clear %edx
1: movl %edx, (%edi) # store %edx into address in %edi
addl $4, %edi # point to next address
loop 1b # loop according to %ecx
mov $k_stack, %esp # point stack pointer to the stack
# hardware init
call pic_init # Programmable Interrupt Controller
call gdt_install # Global Descriptor Table
call idt_install # Interrupt Descriptor Table
# jump into kernel
call kmain
/* If the system has nothing more to do, put it in an infinite loop */
cli # disable interrupts
h: hlt # wait for interrupt
jmp h # continue waiting for interrupt
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