def builtin_4dup(a, b, c, d):
	"""Modify the stack: ( a b c d -- a b c d a b c d )."""
	d2 = type(d)(d.value)
	c2 = type(c)(c.value)
	b2 = type(b)(b.value)
	a2 = type(a)(a.value)
	return (a, b, c, d, a2, b2, c2, d2)