95 lines
2.8 KiB
Scheme
95 lines
2.8 KiB
Scheme
; Copyright (c) 1999-2001 by Martin Gasbichler. See file COPYING.
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;;; Functional event system.
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;;; System by Olin Shivers, implementation by Martin Gasbichler
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(define-record-type sigevent :sigevent
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(really-make-sigevent type next)
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sigevent?
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(type sigevent-type set-sigevent-type!)
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(next sigevent-next set-sigevent-next!))
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(define (make-sigevent type)
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(really-make-sigevent type #f))
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(define empty-sigevent (make-sigevent #f))
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(define *most-recent-sigevent* empty-sigevent)
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(define (most-recent-sigevent) *most-recent-sigevent*)
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(define sigevent-thread-queue #f)
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;Wait for an sigevent of a certain type.
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(define (rts-next-sigevent pre-sigevent set type-in-set?)
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(with-interrupts-inhibited
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(lambda ()
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(let lp ((pre-sigevent pre-sigevent))
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(let ((sigevent (sigevent-next pre-sigevent)))
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(if sigevent
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(if (type-in-set? (sigevent-type sigevent) set)
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sigevent
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(lp sigevent))
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(begin (block-on-queue sigevent-thread-queue)
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(lp pre-sigevent))))))))
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; same as above, but don't block
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(define (rts-next-sigevent/no-wait pre-sigevent set type-in-set?)
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(let ((sigevent (sigevent-next pre-sigevent)))
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(if sigevent
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(if (type-in-set? (sigevent-type sigevent) set)
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sigevent
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(rts-next-sigevent/no-wait (sigevent-next sigevent)
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set
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type-in-set?))
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#f)))
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;Called when the interrupt actually happened.
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;;; TODO w-i-i is problaly not necessary since they're off already
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(define (register-interrupt type)
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(let ((waiters (with-interrupts-inhibited
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(lambda ()
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(set-sigevent-next! *most-recent-sigevent* (make-sigevent type))
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(set! *most-recent-sigevent* (sigevent-next *most-recent-sigevent*))
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(do ((waiters '() (cons (maybe-dequeue-thread! sigevent-thread-queue)
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waiters)))
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((thread-queue-empty? sigevent-thread-queue)
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waiters))))))
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(for-each make-ready waiters)))
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;;; Records whether the sigevent system is running.
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;;; If set to #f we ignore threads waiting for a sigevent.
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(define sigevents-running? #f)
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;;; has to be called with interrupts disabled
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(define (waiting-for-sigevent?)
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(if sigevents-running?
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(not (thread-queue-empty? sigevent-thread-queue))
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#f))
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(define (with-sigevents thunk)
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(set! sigevent-thread-queue (make-queue))
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(set-interrupt-handler! (enum interrupt os-signal)
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(lambda (type enabled-interrupts)
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; type is already set in the unix signal handler
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(register-interrupt type)))
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(set-interrupt-handler! (enum interrupt keyboard)
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(lambda (enabled-interrupts)
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(register-interrupt (enum interrupt keyboard))))
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(dynamic-wind
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(lambda ()
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(set! sigevents-running? #t))
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thunk
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(lambda ()
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(set! sigevents-running? #f))))
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;;; the vm uses the timer for the scheduler
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(define (schedule-timer-interrupt! msec)
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(spawn (lambda ()
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(sleep msec)
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(register-interrupt (enum interrupt alarm)))))
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