extern getnum
	extern putnum
	extern usage
	extern gcd

	global start

	section .text

start:

	;; check that there are two arguments
	pop rax
	cmp rax,3
	jne usage

	;; remove the pointer to the string for the program name
	pop rax

	;; now retrieve the point to the string for the first argument, answer comes back in r15
	pop rax
	call getnum
	mov rbx,r15

	;; now retrieve the point to the string for the second argument
	pop rax
	call getnum
	mov rcx,r15

	;; and now call our gcd; it expects its arguments in rbx and rcx, and returns its argument in rbx
	call gcd

	;; answer came back in rbx, time to call putnum, but it expects its arguments in rax
	mov rax,rbx
	call putnum

	;; output an end-of-line
	call puteoln

	;; and call exit
	mov rdi,0		; program ended normally
	mov rax,60		; exit code
	syscall


puteoln:

	mov rdi,1
	mov rsi,eoln
	mov rdx,1
	mov rax,1
	syscall

	ret


eoln:	db 10