extern printf
extern scanf
global main

section .data
znak db 0
fmt db "%c",0
l1 dq 0
l2 dq 0
fmt2 db "%d",0
fmt3 db "%d",10,0

section .text
main:
mov rdi,fmt
mov rsi,znak
xor rax,rax
call scanf

mov rdi,fmt2
mov rsi,l1
xor rax,rax
call scanf

mov rdi,fmt2
mov rsi,l2
xor rax,rax
call scanf

mov r12,qword [l1]
mov r13,qword [l2]

cmp byte [znak],'+'
je dodaj
jmp odejmij

dodaj:
add r12,r13
jmp koniec

odejmij:
sub r12,r13
jmp koniec

koniec:
mov rdi,fmt3
mov rsi,r12
xor rax,rax
call printf

mov rax,1
mov rbx,0
int 80h