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Last active July 31, 2019 16:01
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; Very simple booting code
; Copyright (C) 2011 Alessandro Ghedini <>
; --------------------------------------------------------------
; "THE BEER-WARE LICENSE" (Revision 42):
; Alessandro Ghedini wrote this file. As long as you retain this
; notice you can do whatever you want with this stuff. If we
; meet some day, and you think this stuff is worth it, you can
; buy me a beer in return.
; --------------------------------------------------------------
org 7C00h ; where BIOS wants me to be loaded
section .data
msg db "Fuck yeah!", 0 ; string to be printed
section .text
global start
cli ; disable interrupts (not really needed)
mov SI, msg ; setup SI for our string (used by lodsb)
mov AH, 0Eh ; set BIOS int to print a char
lodsb ; load the next byte to be printed
cmp AL, 0 ; if AL is 0 we are at the end of the string
je $ ; loop to infinity and beyond if AL is 0
int 10h ; BIOS interrupt call (print byte)
jmp print ; re-do
ISO=genisoimage -input-charset utf-8 -boot-load-size 4 -no-emul-boot -r
all: boot.iso
boot.bin: boot.asm
$(ASM) -o boot.bin boot.asm
boot.iso: boot.bin
mkdir iso/
cp boot.bin iso/boot
$(ISO) -b boot -no-emul-boot -o boot.iso iso 2> /dev/null
run: boot.iso
qemu -boot once=d -cdrom boot.iso
rm -rf *.iso *.bin iso/
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