anchor.diff:  
   (defun decode+rgv64 (context opcode-byte rex opcode)
     (declare (ignore context))
  -  `(,opcode ,(decode-gpr64 (ldb (byte 3 0) opcode-byte) (rex-b rex))))
  +  (make-instruction opcode
  +                    (decode-gpr64 (ldb (byte 3 0) opcode-byte) (rex-b rex))))
   
   (defun decode-ev-gv (context opcode-byte rex opcode16 opcode32 opcode64)
     (declare (ignore opcode-byte opcode16))
  
positive.code:       (disassemble-ordinary-modr/m context rex)
      (if (rex-w rex)
          (and opcode64
               `(,opcode64 ,(decode-gpr64 reg (rex-r rex))
                           ,(decode-gpr64-or-mem r/m (rex-b rex))))
          (and opcode32
               `(,opcode32 ,(decode-gpr32 reg (rex-r rex))
                           ,(decode-gpr32-or-mem r/m (rex-b rex)))))))
  
  (defun decode-ev64 (context opcode-byte rex group-table)
    (declare (ignore opcode-byte))
  
negative.code:       (disassemble-ordinary-modr/m context rex)
      (if (rex-w rex)
          (and opcode64
               (make-instruction opcode64
                                 (decode-gpr64-or-mem r/m (rex-b rex))
                                 (decode-gpr64 reg (rex-r rex))))
          (and opcode32
               (make-instruction opcode32
                                 (decode-gpr32-or-mem r/m (rex-b rex))
                                 (decode-gpr32 reg (rex-r rex)))))))
  
  (defun decode-gv-ev (context opcode-byte rex opcode16 opcode32 opcode64)
    (declare (ignore opcode-byte opcode16))
  