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# declare some constants
.set ALIGN, 1<<0 # align loaded modules on page boundaries
.set MEMINFO, 1<<1 # provide memory map
.set FLAGS, ALIGN | MEMINFO # this is the Multiboot 'flag' field
.set MAGIC, 0x1BADB002 # 'magic number' lets bootloader find the header
.set CHECKSUM, -(MAGIC + FLAGS) # checksum of above, to prove we are multiboot
# the bootloader will search for this magic sequence
# and recognize us as a multiboot kernel
.section .multiboot
.align 4
.long MAGIC
.long FLAGS
.long CHECKSUM
# allocatable, writable, contains no data
.section .bootstrap_stack, "aw", @nobits
stack_bottom:
.skip 16384 # 16 KiB
stack_top:
# the linker script specifies _start as the entry point to the kernel and the
# bootloader will jump to this position once the kernel has been loaded
.section .text
.global _start
.type _start, @function
_start:
movl $stack_top, %esp
push %eax
push %ebx
call kernel_main
cli
hang:
hlt
jmp hang
# Set the size of the _start symbol to the current location '.' minus its start.
# This is useful when debugging or when you implement call tracing.
.size _start, . - _start
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