Recursive fibonacci in IA32 assembly implementation

Question

I currently have the following code for recursively calculating the nth term of the fibonacci sequence in assembly, however it is not working appropriately (only works for the first 3 terms). Could anyone provide any insight?

pushl %ebp 
movl %esp,%ebp
movl 8(%ebp),%eax        #retrieve argument passed to function in eax
cmpl $1,%eax             #identify if its base case     
jle fin  
decl %eax               
pushl %eax               #push n-1 to stack for next function call
call _fibonacci         
movl %eax,%ecx           #store fib(n-1) in ecx
movl 8(%ebp),%eax        
subl $2,%eax
pushl %eax              #push n-2 to stack for next function call
call _fibonacci
addl %ecx,%eax          #add fib(n-2)+fib(n-1)
fin:                    #end label
movl %ebp,%esp
popl %ebp
ret

Answer 1

call _fibonacci
addl %ecx,%eax          #add fib(n-2)+fib(n-1)

Your _fibonacci function uses %ecx without saving it (in the non-base case), so the recursive call overwrites the value in %ecx .

You should save the returned value from the first call to _fibonacci on the stack instead of in a register.