;;; Make a fixnum out of NUM. (I.e. shift by two bits if it will fit.)
(defun fixnumize (num)
(if (fixnump num)
- (ash num (1- n-lowtag-bits))
+ (ash num n-fixnum-tag-bits)
(error "~W is too big for a fixnum." num)))
;;; Determining whether a constant offset fits in an addressing mode.