boot.asm

; Solution to exercise at end of https://youtu.be/APiHPkPmwwU
; to execute $ nasm boot.asm -f bin -o boot.bin && qemu-system-x86_64 -drive file=boot.bin,format=raw
mov ah, 0x0e
mov al, 97
mov dl, 97
int 0x10

loop:
	inc dl
	mov al, dl
	and dl, 1
	mov dl, al
	jz noShift
	mov dl, al
	sub al, 32
noShift:
	int 0x10
	cmp dl, 'z'
	jne loop
jmp $
times 510-($-$$) db 0
db 0x55, 0xaa