%define opcode 0xAB50

start:
push ds ; stack -> ds
pop es ; es -> ds, stack is empty
; mov es, ds ;; this does not work

push ds
pop ss ; ss -> ds
; moved es and ss to the arena

; equal to this
; mov bx, ds
; mov es, bx

mov sp, ax
mov di, ax
add di, finish
;; di -> our end
;; sp -> our beginning

mov ax, opcode
loop1:
stosw
;; stosw does this:
;; mov [es:di], ax
;; add di, 2
finish:

;; this will write to the next two bytes the opcodes of :
;; push ax
;; stosw