Hello world

## boot.asm
; boot.asm

; setup segment register
mov ax, 0x07c0
mov ds, ax

; setup display
mov ah, 0x0     ;setup video mode
mov al, 0x3     ;0x3 = text mode, color, 80x25
int 0x10        ;0x10 = video service

mov si, msg     ;target of lodsb
mov ah, 0x0E    ;0x0E = tty

print_character_loop:
    lodsb

    or al, al
    jz hang     ;jump if zero

    int 0x10    ;when ah is 0x0E, then print

    jmp print_character_loop

msg:
    db 'Hello World!', 13, 10, 0    ;13 = \r, 10 = \n, 0 = NULL


hang:
    jmp hang

    times 510-($-$$) db 0

; this is a comment

    db 0x55
    db 0xAA

## Makefile
boot.bin: boot.asm
	nasm -f bin boot.asm -o boot.bin

qemu: boot.bin
	qemu-system-x86_64 -curses boot.bin

clean:
	rm *.bin