name "add-sub"

org 100h

mov al, 5       ; bin=00000101b 
mov bl, 10      ; hex=0ah or bin=00001010b 

; 5 + 10 = 15 (decimal) or hex=0fh or bin=00001111b 
add bl, al

; 15 - 1 = 14 (decimal) or hex=0eh or bin=00001110b 
sub bl, 1

; print result in binary: 
mov cx, 8
print: mov ah, 2   ; print function. 
       mov dl, '0'
       test bl, 10000000b  ; test first bit. 
       jz zero
       mov dl, '1'
zero:  int 21h
       shl bl, 1
loop print

; print binary suffix: 
mov dl, 'b'
int 21h

; wait for any key press: 
mov ah, 0
int 16h

ret