boot.s (view raw)
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.section .text
# disable interrupts
cli
# canonicalize %CS:%EIP to a known value
ljmp $0, $start
start:
# setup segments
mov $0x0000, %ax
mov %ax, %ss
mov %ax, %ds
mov %ax, %es
mov %ax, %fs
# setup stack
mov $0x9000, %ax
mov %ax, %bp
mov %ax, %sp
# select display page 0
movb $0, %al
movb 0x05, %ah
int $0x10
# print hello world
mov $message, %si
mov $0x0000, %bx
mov $0x0E, %ah
print_loop:
lodsb
or %al, %al
jz print_end
int $0x10
jmp print_loop
print_end:
# loop forever
loop:
jmp loop
# some data
message: .ascii "Hello World!\n\0"
end:
.=510
.byte 0x55
.byte 0xAA