; SI = pointer to start of string to be printed
os_print_string:
	pusha

	mov ah, 0Eh			; int 10h teletype function, we're telling the BIOS we will print something

.repeat:
	lodsb				; Get char from si into al
	cmp al, 0			; Compare al to 0
	je .done			; If char is zero, end of string

	int 10h				; Otherwise, print it
	jmp .repeat			; And move on to next char

.done:
	popa
	ret

; Exact same as the above procedure, but this adds a newline 
; after priting, similar to the difference between Rust's print! and println!
os_print_string_nl:				
	pusha

	mov ah, 0Eh			; int 10h teletype function, we're telling the BIOS we will print something

.repeat:
	lodsb				; Get char from si into al
	cmp al, 0			; Compare al to 0
	je .done			; If char is zero, end of string

	int 10h				; Otherwise, print it
	jmp .repeat			; And move on to next char

.done:
	call os_print_newline
	popa
	ret

; --------------------------------------------

os_print_newline:
	pusha
	
	mov ah, 0Eh
	mov al, 13
	int 10h
	mov al, 10
	int 10h

	popa
	ret

; -------------------------------------------

os_set_text_mode:
	pusha
	; Set mode = 80x25 (text mode)
	mov ah, 00h
	mov al, 03h
	int 10h

	; Move cursor to the top left
	mov ah, 02h
	mov dh, 0
	mov dl, 0
	int 10h

	popa
	ret