anchor.diff:  
   (defun irq-fifo-reset (fifo)
     "Flush any waiting data."
  +  (check-type fifo irq-fifo)
     (safe-without-interrupts (fifo)
       (with-place-spinlock ((irq-fifo-lock fifo))
         (setf (irq-fifo-head fifo) 0
  
positive.code: (defun condition-notify (condition-variable &optional broadcast)
    "Wake one or many threads waiting on CONDITION-VARIABLE.
  May be used from an interrupt handler, assuming the associated mutex is interrupt-safe."
    (safe-without-interrupts (condition-variable broadcast)
      (flet ((pop-one ()
               (wake-thread (pop-wait-queue condition-variable))))
  
negative.code:                       :format-arguments (list mutex (mutex-name mutex) current-owner)))))))
  
  (defun release-mutex (mutex)
    (check-type mutex mutex)
    (check-mutex-release-consistence mutex)
    (setf (mutex-owner mutex) nil)
    (when (not (eql (sys.int::cas (mutex-state mutex) :locked :unlocked) :locked))
  