scsh-0.5/rts/interrupt.scm

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1995-10-13 23:34:21 -04:00
; Copyright (c) 1993, 1994 Richard Kelsey and Jonathan Rees. See file COPYING.
; Interrupts
(define interrupt-handlers
(make-vector interrupt-count 0))
(do ((i 0 (+ i 1)))
((= i interrupt-count))
(vector-set! interrupt-handlers i
(lambda (enabled-int)
(signal 'interrupt i enabled-int))))
(define (initialize-interrupts!)
(set-interrupt-handlers! interrupt-handlers)
(set! one-second (time time-option/ticks-per-second #f))
(set-enabled-interrupts! all-interrupts))
(define time-option/ticks-per-second (enum time-option ticks-per-second))
(define one-second #f)
(define no-interrupts 0)
(define all-interrupts (- (arithmetic-shift 1 interrupt-count) 1))
(define (with-interrupts-inhibited thunk)
(with-interrupts no-interrupts thunk))
(define (with-interrupts-allowed thunk)
(with-interrupts all-interrupts thunk))
(define (with-interrupts interrupts thunk)
;; I might consider using dynamic-wind here, but (a) I'm worried
;; about the speed of thread switching (which uses this) and (b)
;; it's a pretty bad idea to throw in or out of one of these anyhow.
(let ((ei (set-enabled-interrupts! interrupts)))
(call-with-values thunk
(lambda results
(set-enabled-interrupts! ei)
(apply values results)))))
(define (enabled-interrupts) ;For debugging
(let ((e (set-enabled-interrupts! 0)))
(set-enabled-interrupts! e)
e))
; Signal an interrupt if an insufficient amount of memory is reclaimed by
; a garbage collection. The amount defaults to 10% of the heap.
(define (interrupt-before-heap-overflow! . maybe-required-space)
(let ((space (if (null? maybe-required-space)
(quotient (memory-status memory-status-option/heap-size 0)
10)
(car maybe-required-space))))
(vector-set! interrupt-handlers
interrupt/memory-shortage
(lambda (ei)
(memory-status
memory-status-option/set-minimum-recovered-space!
space)
(signal 'interrupt interrupt/memory-shortage ei)))
(memory-status memory-status-option/set-minimum-recovered-space!
space)))
(define interrupt/memory-shortage (enum interrupt memory-shortage))
(define memory-status-option/set-minimum-recovered-space!
(enum memory-status-option set-minimum-recovered-space!))
(define memory-status-option/heap-size
(enum memory-status-option heap-size))