;Converts a byte in AL to a hex string at DI.

byte2hex:

;Store the initial registers in the stack
push si
push ax
push bx
push cx

;Move the byte to AH
mov ah, al

;Set a key for the hex digits
mov si, .key

;Set a counter for the two hex digits
mov cx, 0x2

.loop:

;Read a nibble
rol ax, 0x1
rol ax, 0x1
rol ax, 0x1
rol ax, 0x1
mov bx, ax

;Convert the nibble to a hex digit
and bx, 0xf
mov bl, [si + bx]

;Store the hex digit
mov [di], bl

;Repeat
inc di
dec cx
jnz .loop

;Load the initial registers from the stack
pop cx
pop bx
pop ax
pop si

ret

.key db "0123456789abcdef"