GCD and LCM of two numbers, implemented with Forth

gcd.fth

\ This implements Euclidean algorithm in Forth
: gcd ( X Y )
	2dup <= if swap ( Y X ) then
	( X Y )
	begin
		tuck ( Y X Y )
		mod ( Y Z )
		dup ( Y Z Z )
	0= until ( Y Z )
	( Y 0 )
	drop ( Y )
;

\ Calculates LCM of two integers
: lcm ( X Y )
	2dup ( X Y X Y )
	* ( X Y P )
	rot rot ( P X Y )
	gcd ( P Q )
	/ ( LCM )
;