data segment
a db 3
b db 3
data ends
code segment
assume ds:data,cs:code
start:
mov ax,data
mov ds,ax
test a,1
jz next1
test b,1
jz tj
inc a
inc b
jmp tj
next1:
test b,1
jz tj
mov al,a
xchg al,b
mov a,al
tj:
mov ah,4ch
int 21h
code ends
end start
就if语句