anchor.diff:             (fixnum-check :r9)
              (load-in-reg :r8 x t)
              (fixnum-check :r8)
  +           (smash-r8)
              (emit `(sys.lap-x86:or64 :r8 :r9))
              (setf *r8-value* (list (gensym))))))
   
  
positive.code:              (fixnum-check :r9)
               (load-in-reg :r8 x t)
               (fixnum-check :r8)
               (emit `(sys.lap-x86:add64 :r8 :r9)
                     `(sys.lap-x86:jo ,ovfl))
               (setf *r8-value* (list (gensym)))))))
  
negative.code:     (emit-trailer (type-error-label)
  		  (raise-type-error :r8 '(simple-array * (*))))
      (load-in-r8 array t)
      (smash-r8)
      (emit `(sys.lap-x86:mov8 :al :r8l)
  	  `(sys.lap-x86:and8 :al #b1111)
  	  `(sys.lap-x86:cmp8 :al #b0111)
  