anchor.diff:      ;; If the aux clock bit is clear, then it can't be a dual-channel controller.
       (unless (logtest config-byte +ps/2-config-aux-clock+)
         (setf single-channelp t))
  -    (format t "Config word: ~8,'0B~%" config-byte)
       ;; Disable the key and aux interrupts and key translation.
       (ps/2-write-config (logand config-byte
                                  (lognot (logior +ps/2-config-key-interrupt+
  
positive.code:       (setf (isa-pic-irq-mask +ps/2-aux-irq+) nil))
      ;; Flush data FIFOs.
      (ps/2-flush-input :key)
      (ps/2-flush-input :aux)
      (format t "Config word: ~8,'0B  KEY: ~S  AUX: ~S (after setup)~%"
              (ps/2-read-config)
              *ps/2-key-port-working*
              *ps/2-aux-port-working*)))
  
  (defun ps/2-write (port byte)
    (ecase port
  
negative.code:       (setf (io-port/8 +ps/2-control-port+) +ps/2-enable-aux-port+)
        ;; This bit should be clear now, for a dual-channel controller.
        (setf config-byte (ps/2-read-config))
        (when (logtest config-byte +ps/2-config-aux-clock+)
          (setf single-channelp t))
        (ps/2-input-wait "disable-aux")
  