(inst lea header ; (w-1 << 8) | type
(make-ea :qword :base header :disp (+ (ash -2 n-widetag-bits) type)))
(inst and bytes (lognot lowtag-mask))
(inst lea header ; (w-1 << 8) | type
(make-ea :qword :base header :disp (+ (ash -2 n-widetag-bits) type)))
(inst and bytes (lognot lowtag-mask))