[bits 16]

BLANK:
    db 0x12

SPACE:
    db " ",0

;print_string routine ([bx])
;this routine will print a null terminated string at [bx] to the screen.
print_string:

    pusha			;push all registers
    mov ah,0x0e

    print_string_loop:

	;check if value at [bx] is "\0" (end of string)
	mov cl,[bx]
	cmp cl,0
	je print_string_finish

	;otherwise instruct BIOS to print the current char
	mov al,cl
	int 0x10

	;proceed with next char
        inc bx
	jmp print_string_loop

    print_string_finish:

    popa			;pop all registers
    ret				;return to caller

print_clear:

pusha
    mov ah,0x6	    ;func
    mov al,0	    ;scroll one line
    mov bh,[BLANK]  ;blank char

    mov ch,0	    ;upper left corner
    mov cl,0
    mov dh,20	    ;lower right corner
    mov dl,40
    int 0x10

    mov ah,0x2
    mov bh,0
    mov dl,0
    mov dh,20
    int 0x10
popa

print_nextline:

    pusha

    mov ah,0x6	    ;func
    mov al,1	    ;scroll one line
    mov bh,[BLANK]  ;blank char

    mov ch,0	    ;upper left corner
    mov cl,0
    mov dh,20	    ;lower right corner
    mov dl,40
    int 0x10


    mov ah,0x3
    mov bh,0
    int 0x10


    mov ah,0x2
    mov dl,0
    int 0x10

    mov bx,SPACE
    call print_string

    popa
    ret


;print byte from al to screen
 print_hex_byte: 

 pusha

   mov [.temp],al
   shr al,4
   cmp al,10
   sbb al,69h
   das
 
   mov ah,0Eh
   int 10h
 
   mov al,[.temp]
   ror al,4
   shr al,4
   cmp al,10
   sbb al,69h
   das
 
   mov ah,0Eh
   int 10h

popa
 
   ret
 
 .temp db 0