anchor.diff:           (emit '(sys.lap-x86:lea64 :r8 ((:rax ,(ash 1 sys.int::+n-fixnum-bits+)))))
            (setf *r8-value* (list (gensym)))))
        (defbuiltin ,(intern (format nil "~A-UNSCALED" name) (symbol-package name)) (object offset) ()
  -       (let ((constant-offset (and (constant-type-p offset `(signed-byte ,(- 64 sys.int::+n-fixnum-bits+)))
  +       (let ((constant-offset (and (constant-type-p offset `(signed-byte ,(- 32 sys.int::+n-fixnum-bits+)))
                                      (second offset))))
            (unless constant-offset
              (load-in-reg :rdi offset t)
  
positive.code: (defmacro define-u-b-object-ref (name width read-op write-op register)
    `(progn
       (defbuiltin ,name (object offset) ()
         (let ((constant-offset (and (constant-type-p offset `(signed-byte ,(- 64 sys.int::+n-fixnum-bits+)))
                                     (second offset))))
           (unless constant-offset
             (load-in-reg :rdi offset t)
  
negative.code: ;;   (prog1 (%object-ref-t object slot)
  ;;     (setf (%object-ref-t object slot) new)))
  (defbuiltin sys.int::%xchg-object (object offset new) ()
    (let ((constant-offset (and (constant-type-p offset `(signed-byte ,(- 32 sys.int::+n-fixnum-bits+)))
                                (second offset))))
      (unless constant-offset
        (load-in-reg :rdi offset t)
  