Display a box with a dynamic size [nasm]

[radnomguywfq3]

The book I'm reading says one comment per a line so thats why theres comments all over the place. This was probably the most time consuming thing for the most simple output I've ever done in my life, and I must say, it feels good :O Anyways I'm going to be learning a lot more about the stack soon, so that should make these 112 lines into 70 or 80 lines. I'm probably going to end-up rebuilding the whole bloody thing, but still, it was fun to make.

  [BITS 16]           ; Set 16 bit code generation

        SEGMENT junk  ; Segment containing code

  ..start:

  ;  linker where the code segment begins.

    mov  ax,data      ; Move segment address of data segment into AX
    mov  ds,ax        ; Copy address from AX into DS
    mov  ax,stack     ; Move segment address of stack segment into AX
    mov  ss,ax        ; Copy address from AX into SS

    mov  sp,stacktop  ; Point SP to the top of the stack

    call createBox    ; Call createBox

    jmp quit


;+----------------------+
;|      Functions       +
;+----------------------+

createBox:
    mov cx,010H        ; move 10h to CX register
    call ?drawTop      ; call draw top

    mov bx,0Ah         ; mov 0Ah to BX register

??createBoxLoop:
      mov  cx,010h     ; move 010h to cx register
      call ?drawSides  ; Call drawSides

      dec  bx          ; decrement bx register by one

      call ?eof          ; call eof
      cmp  bx,0h         ; Compare BX,0
     jne ??createBoxLoop ; is CF(Carry Flag) set?

    mov  cx,010h         ; move CX Register to 010h
    call ?drawTop        ; call draw top
    ret                  ; return


;+---------------------+
;|      Sub-Calls      |
;+---------------------+

;DRAW TOP FUNCTIONS
?drawTop:

    mov ah,09h           ; The service we want to call
    mov dx,drawChar      ; THe message we want to draw

 ??drawTopLoop:          ; define loop label
       INT 21h           ; call service from DOS

       dec cx            ; decrease cx register by one
       cmp cx,0h         ; compare CX and 0
      jne ??drawTopLoop  ; if CX != 0h then hump do !draw

    call ?eof            ; call eof
    ret                  ; return

;EOF Functions, outputs ASCII 13 to the console\End of line
?eof:
    mov ah,09h           ; Select service to call from DOS
    mov dx,eofChar       ; mov dx register to EOF char
    int 21h              ; Call selected service
    ret                  ; return

;DRAW SIDES FUNCTIONS
?drawSides:

    mov ah,09h        ; the service within dos we want to call;
    mov dx,drawChar   ; Move dx register to addresses of drawChar

    int 21h           ; call selected service

    mov dx,fillChar   ; move dx register to the address of fillChar
 ??drawSideLoop:
       int 21h        ; Call selected service
       dec cx         ; decrease cx
       cmp cx,2h      ; Compare CX and 2h
       jne ??drawSideLoop ; is CF set?

    mov dx,drawChar   ; mov dx register to the address of drawCharacter
    int 21h           ; call selected service
    ret               ; return


;+---------------------+
;|       Jmp to        |
;+---------------------+

quit:
    mov  ax, 04C00H   ;  select service
    int  21H          ;  Call selected service from DOS



        SEGMENT data  ; Segment containing initialized data

  drawChar   db "+$"
  fillChar   db " $"
  eofChar    db 10,"$"
        SEGMENT stack stack

          resb 64
    stacktop: