.data
        a : .long 6
        r : .long 0
        out : .string "result %d\n"
.text
.global main
fib:
        pushl %ebp
        movl %esp, %ebp
        movl 8(%ebp), %eax
        cmpl $0, %eax #fib(0)=0
        je endf
        cmpl $1, %eax #fib(1)=1
        je endf
        decl %eax #eax=n-1
        pushl %eax #set arg
        call fib #re in ecx
        popl %eax #get n-1
        decl %eax #eax=n-2
        pushl %ecx #save result for n-1
        pushl %eax #set arg
        call fib #res in ecx
        popl %eax # eax=n-2, discard
        popl %eax # eax=fib(n-1)
        addl %eax, %ecx #fib(n)=fib(n-1)+fib(n+2)
        movl %ebp,%esp #Exit
        popl %ebp
        ret
endf:
        movl %eax, %ecx#fib(0) or fib(1) to %ebx
        movl %ebp,%esp
        popl %ebp
        ret

main:
        pushl a  #stack [a]
        call fib #result in %ecx
        popl %eax # remove arg to fib
        pushl %ecx
        pushl $out
        call printf
        addl $8, %esp
        xor %eax, %eax
        ret