Fibonacci n-th number (modulo 2^32) in x86 assembler

fibonacci.asm

; Fibonacci n-th number (modulo 2^32)
;
; input:
; 	ecx = n
; modifies:
; 	eax, ecx, edx
; ouput:
; 	eax = number
; size:
; 	15 bytes

use32

_fibonacci:
	xor    eax, eax           ; 31 c0
	jecxz  _fibonacci_end     ; e3 0a
	dec    ecx                ; 49
	inc    eax                ; 40
	jecxz  _fibonacci_end     ; e3 06
	cdq                       ; 99
_fibonacci_loop:
	xchg   eax, edx           ; 92
	add    eax, edx           ; 01 d0
	loop   _fibonacci_loop    ; e2 fb
_fibonacci_end:
	ret                       ; c3

And here's a version using the same formula but runs in linear time :) :

_start:

        fld     tword [sqrt5]
        fld     tword [n]
        fld     tword [phi]

        fyl2x
        fld     st0
        frndint
        fsub    st1, st0
        fxch    st1
        f2xm1
        fld1
        fadd
        fscale
        fdiv    st2
        fistp  qword [result]
Exit: 
...

@paulfurber: Thanks for providing FP versions! They're not as short as I would like them to be, though. :>

Anyway, I'm not FP guy myself, so I won't fiddle with squeezing it as much as possible (please forgive my rude assumption that it is possible), but others are free to do so in the comments!

And sorry for late reply, but unfortunately gists lacks any notification system...