Hi guys!
I found out a problem in my assembly that i cant push a 8 bit register into the stack. i dont know why buy please do have a look at the code below

Code:
DrawBox proc
              
                mov bx,0
                mov dl,79
                mov al,num[bx]
                sub dl,al            
                
                add cx,dl           ;<----Problem here
                push cx
                
                call PointCursor
                pop ax
                
                mov ah,09h
                mov bh,00h
                mov al,20h
                mov cx,10D
                mov bl,20h
                int 10h

                ret

DrawBox endp
i tried to 'add cx,dl' to change it to 16 bit but failed. Can any 1 please do help me with this register problem. i just need to push the correct value i minus into the stack without error. Thanks!!