Masm Parallel Port Need Help Badly...

I really need some help with regards to this program.. Me and my classmate have written this program before but its such a long time and have forgotten the code.. Please help me by putting some comments on it.. And it does not run but does not have errors on it... Use to light leds using parallel port using masm programming assembly language help me please...

.model small
.stack
.code

mov dx,0378h
mov cx,60000

mov bl, 1

start:

bitis:
mov ax,16 ; bitis on
out dx,ax
loop bitis

off0:
mov ax,00
out dx,ax
loop off0

on:
mov ax,48 ; bitis and 1st
out dx,ax
loop on

off:
mov ax,00
out dx,ax
loop off

on2:
mov ax,80 ; bitis and 2nd
out dx,ax
loop on2

off2:
mov ax,00
out dx,ax
loop off2

on3:
mov ax,144 ; bitis and 3rd
out dx,ax
loop on3

off3:
mov ax,00
out dx,ax
loop off3

on4:
mov ax,240 ; all on
out dx,ax
loop on4

off4:
mov ax,00
out dx,ax
loop off4

all:
mov ax,144 ; bitis and 3rd
out dx,ax
loop all

off5:
mov ax,00
out dx,ax
loop off5

on6:
mov ax,80 ; bitis and 2nd
out dx,ax
loop on6

off6:
mov ax,00
out dx,ax
loop off6

on7:
mov ax,48 ; bitis and 1st
out dx,ax
loop on7

off7:
mov ax,00
out dx,ax
loop off7

on8:
mov ax,16 ; bitis
out dx,ax
loop on8

off8:
mov ax,00
out dx,ax
loop off8

on9:
mov ax,240 ; all on
out dx,ax
loop on9

off9:
mov ax,00
out dx,ax
loop off9

on10:
mov ax,16 ; bitis
out dx,ax
loop on10

off10:
mov ax,00
out dx,ax
loop off10

on11:
mov ax,48 ; bitis and 1st
out dx,ax
loop on11

off11:
mov ax,00
out dx,ax
loop off11

on12:
mov ax,112 ; bitis, 1st and 2nd
out dx,ax
loop on12

off12:
mov ax,00
out dx,ax
loop off12

on13:
mov ax,240 ; bitis, 1st, 2nd and 3rd
out dx,ax
loop on12

off13:
mov ax,00
out dx,ax
loop off13

on14:
mov ax,112 ; bitis, 1st and 2nd
out dx,ax
loop on14

off14:
mov ax,00
out dx,ax
loop off14

on15:
mov ax,48 ; bitis and 1st
out dx,ax
loop on15

off15:
mov ax,00
out dx,ax
loop off15

on16:
mov ax,16 ; bitis
out dx,ax
loop on16

off16:
mov ax,00
out dx,ax
loop off16

on17:
mov ax,240 ; bitis, 1st, 2nd and 3rd
out dx,ax
loop on17

off17:
mov ax,00
out dx,ax
loop off17

on18:
mov ax,240 ; bitis, 1st, 2nd and 3rd
out dx,ax
loop on18

off18:
mov ax,00
out dx,ax
loop off18

on13:
mov ax,240 ; bitis, 1st, 2nd and 3rd
out dx,ax
loop on12

off19:
mov ax,00
out dx,ax
loop off19


inc bl
cmp bl,20
jne start

mov ah,04ch
int 21h
end