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; Part of Scheme 48 1.9. See file COPYING for notices and license.
; Authors: Richard Kelsey, Jonathan Rees, Marcus Crestani, Mike Sperber
; Alternate implementation of PRIMITIVES module.
(define underlying-error error)
(define (unspecific) (if #f #f))
; Records
(define-record-type new-record :new-record
(make-new-record fields)
record?
(fields new-record-fields))
(define (make-record size init)
(make-new-record (make-vector size init)))
(define (record-ref r i)
(vector-ref (new-record-fields r) i))
(define (record-set! r i value)
(vector-set! (new-record-fields r) i value))
(define (record-length r)
(vector-length (new-record-fields r)))
; Extended numbers
(define-record-type new-extended-number :new-extended-number
(make-new-extended-number fields)
extended-number?
(fields new-extended-number-fields))
(define-record-discloser :new-extended-number
(lambda (n) `(extended-number ,(new-extended-number-fields n))))
(define (make-extended-number size init)
(make-new-extended-number (make-vector size init)))
(define (extended-number-ref n i)
(vector-ref (new-extended-number-fields n) i))
(define (extended-number-set! n i value)
(vector-set! (new-extended-number-fields n) i value))
(define (extended-number-length n)
(vector-length (new-extended-number-fields n)))
; Current thread
(define *current-thread* 'uninitialized-current-thread)
(define (current-thread) *current-thread*)
(define (set-current-thread! thread)
(if (not (and (record? thread)
(list? (record-ref thread 1))))
(underlying-error "invalid current thread" thread))
(set! *current-thread* thread))
; Etc.
(define (close-port port)
((if (input-port? port) close-input-port close-output-port)
port))
(define (write-string s port)
(display s port))
(define (write-string-tail s start port)
(display (substring s start (port))))
(define (schedule-interrupt interval)
(if (not (= interval 0))
(warn "ignoring schedule-interrupt" interval)))
(define *pseudo-enabled-interrupts* 0)
(define (set-enabled-interrupts! ei)
(let ((previous *pseudo-enabled-interrupts*))
(set! *pseudo-enabled-interrupts* ei)
;; (if (bitwise-and *pseudo-pending-interrupts* ei) ...)
previous))
(define *pseudo-pending-interrupts* 0)
(define *pseudo-exception-handlers* #f)
(define (set-exception-handlers! h)
(let ((old *pseudo-exception-handlers*))
(set! *pseudo-exception-handlers* h)
old))
(define *pseudo-interrupt-handlers* #f)
(define (set-interrupt-handlers! v)
(let ((old *pseudo-interrupt-handlers*))
(set! *pseudo-interrupt-handlers* v)
old))
(define (unimplemented name)
(lambda args (underlying-error "unimplemented primitive" name args)))
(define collect (unimplemented 'collect))
(define call-external-value (unimplemented 'call-external-value))
(define call-external-value-2 (unimplemented 'call-external-value-2))
(define lookup-shared-binding (unimplemented 'lookup-shared-binding))
(define define-shared-binding (unimplemented 'define-shared-binding))
(define undefine-shared-binding (unimplemented 'undefine-shared-binding))
(define (shared-binding? x) #f)
(define make-shared-binding (unimplemented 'make-shared-binding))
(define shared-binding-name (unimplemented 'shared-binding-name))
(define shared-binding-is-import? (unimplemented 'shared-binding-is-import?))
(define shared-binding-ref (unimplemented 'shared-binding-ref))
(define shared-binding-set! (unimplemented 'shared-binding-set!))
(define find-undefined-imported-bindings (unimplemented 'find-undefined-imported-bindings))
(define find-all (unimplemented 'find-all))
(define vm-extension (unimplemented 'vm-extension))
(define (memory-status which arg)
(case which
((2) 100)
((3) (display "(Ignoring set-minimum-recovered-space!)") (newline))
(else (underlying-error "unimplemented memory-status" which arg))))
(define (time which arg)
(case which
((0) 1000)
(else (underlying-error "unimplemented time" which arg))))
; end of definitions implementing PRIMITIVES structure
; --------------------
; Auxiliary crud.
(define (maybe-handle-interrupt which)
;; Should actually do (get-highest-priority-interrupt!) ...
(let ((bit (arithmetic-shift 1 which)))
(cond ((= (bitwise-and *pseudo-enabled-interrupts* bit) 0)
(set! *pseudo-pending-interrupts*
(bitwise-ior *pseudo-pending-interrupts* bit))
(display "(Interrupt deferred)")
(newline)
#f)
(else
(set! *pseudo-pending-interrupts*
(bitwise-and *pseudo-pending-interrupts*
(bitwise-not bit)))
(display "(Handling interrupt)")
(newline)
((vector-ref *pseudo-interrupt-handlers* which)
(set-enabled-interrupts! 0))
#t))))
(define (raise-exception opcode exception arguments)
(apply (vector-ref (get-exception-handlers) opcode)
(cons exception arguments)))
(define (get-exception-handlers)
*pseudo-exception-handlers*)
(define (clear-registers!)
(set! *current-thread* 'uninitialized-current-thread)
(set! *pseudo-enabled-interrupts* 0)
(set! *pseudo-interrupt-handlers* #f)
(set! *pseudo-exception-handlers* #f))
(define *vm-return* #f)
(define (vm-return . rest)
(if *vm-return*
(apply *vm-return* rest)
(underlying-error "vm-return" rest)))
(define (?start entry-point arg) ;E.g. (?start (usual-resumer bare #t) 0)
(clear-registers!)
(call-with-current-continuation
(lambda (k)
(set! *vm-return* k)
(entry-point arg
(current-input-port)
(current-output-port)))))
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