SECTION	.text
		ALIGN	16
		BITS	32

		GLOBAL	_factorial
_factorial:
		; function returns n! when called as factorial(n)
		; return value is expected in EAX by DJGPP compiler
	
		; move (copy) number from stack into register EAX
		MOV	ECX,[ESP+4]

		MOV	EAX,1
		
		CMP	ECX,0
		JBE	L2	; jump to L2 if parameter <= 0, return 1
		
L1:		MUL	ECX	; Perform EDX:EAX = EAX*ECX
		LOOP	L1	; decrement ECX and go to L1 if ECX != 0
		

L2:		RET		; Return to calling program.