oode segmment
assume cs:code
start: mov ax.0
mov ds,ax
mov bx,70h
mov word ptr ds:[bx],offset show
mov word ptr ds:[bx],seg show
mov bl, 'a'
sti
mov bx,offffh
de1: dec bx
mov ax,0ffffh
de2: dec ax
cmp ax,0
...