fibanocci in x86

fib.s

# compile: gcc -o fib fib.s -m32
# run: ./fib <number>
.global main
.data
    formatstr: .asciz "fib(%d)= %d\n"

main:	
    pop %ecx
    movl 4(%eax),%edx
    pushl %edx
    call atoi
    push %eax
    movl %eax,%edi
    call fib

    pushl %eax
    pushl %edi
    pushl $formatstr
    call printf
    call exit
fib:
    pushl %ebp
    movl %esp, %ebp

    subl $4,%esp
    movl 8(%ebp),%edx

    cmpl $1,%edx
    je fib_base
    cmpl $0,%edx
    je fib_base
    
    decl %edx
    push %edx
    call fib
    movl %eax,-4(%ebp)
    pop %edx

    decl %edx
    push %edx
    call fib
    addl -4(%ebp),%eax
    leave
    ret
fib_base:
    movl $1,%eax
    leave
    ret