assembly language program help

Shynash21's Avatar, Join Date: May 2011
Newbie Member
Hello the below 8086 ALP program is to display FIRE and HELP messages alternatively with flickering effects on a seven segment display interface...
Code:
.model small
.data
msg1 db 86h,88h,of9h,8eh  
msg2 db 8ch,0c7h,86h,89h  
.code
mov ax,@data
mov ds,ax
mov dx,133h
mov al,80h
out dx,al
mov cx,25
again: lea si,msg1
          push cx
          call disp
          call delay
          lea si,msg2
          call disp 
          call delay
          pop cx
          loop again 
         mov ah,4ch
         int 21h

  disp proc near
  mov cx,04
l1:   mov bl,08
     mov al,[si]
l2:  rol al,01
     mov dx,131h
    out dx,al
    push ax
    mov al,0ffh
   mov dx,132h
   out dx,al
   dec bl
   pop ax
   jnz l1
l3:  inc si
     loop l1
     ret
    disp endp
please explain me how the codes in msg1 and msg 2 are equivalent to "FIRE" and "HELP" and please explain me the display procedure of the 7 segment display interface

Last edited by shabbir; 13May2011 at 11:14.. Reason: Code blocks
0
neo_vi's Avatar, Join Date: Feb 2008
Invasive contributor
It depends whether the 7 segment Common cathode or common anode.
Please refer http://en.wikipedia.org/wiki/Seven-segment_display
and you can convert accordingly.
Hope this helps