;;; -*- Mode:LISP; Package:TCP; Base:10; Patch-File:T; Readtable:ZL -*-


(DEFVAR *HANDLE-OWN-EXINTR-WINS* 0)
(DEFVAR *HANDLE-OWN-EXINTR-CALLS* 0)

(DEFVAR *HANDLE-OWN-EXINTR-BUSY* 200)


(DEFUN HANDLE-OWN-EXINTR-STATS (&OPTIONAL RESETP)
  (FORMAT T "~&~D calls, ~D wins, ~D percent, BUSY LOOP COUNT = ~D~%"
	  *HANDLE-OWN-EXINTR-CALLS*
	  *HANDLE-OWN-EXINTR-WINS*
	  (ROUND (TIMES *HANDLE-OWN-EXINTR-WINS* 100)
		 (IF (ZEROP *HANDLE-OWN-EXINTR-CALLS*) 1
		   *HANDLE-OWN-EXINTR-CALLS*))
	  *HANDLE-OWN-EXINTR-BUSY* )
  (when RESETP
    (setq *HANDLE-OWN-EXINTR-WINS* 0)
    (setq *HANDLE-OWN-EXINTR-CALLS* 0)))


(DEFUN EXINTR-MESSAGE-READYP ()
  (ZEROP (LOGAND (READ-UCHAR *DMA* (MSG-OFFSET (RMSG-AREA-LASTR RMSGAREA)) 'MESSAGES-STATUS)
		 (LOGIOR MQ-DONE MQ-EXOS))))



(DEFUN EXINTR-WAIT ()
  (PROCESS-WAIT "Exintr wait"
		#'(LAMBDA ()
		    (WHEN (AND (NOT (EQ *EXINTR-IN-PROCESS* :USER))
			       (EXINTR-MESSAGE-READYP))
		      ;; Note, just because the wait function returns T doesnt
		      ;; mean that our process will be run next. That is why
		      ;; we use the flag values of NIL, :SYSTEM, :USER rather than
		      ;; just T and NIL.
		      (SETQ *EXINTR-IN-PROCESS* :SYSTEM)))))

      

(DEFUN HANDLE-OWN-EXINTR (KP)
  (WHEN (%STORE-CONDITIONAL (LOCF *EXINTR-IN-PROCESS*) NIL :USER)
    (INCF *HANDLE-OWN-EXINTR-CALLS*)
      (DO ((J 0 (1+ J)))
	  ((OR (EXINTR-MESSAGE-READYP)
	       (= J *HANDLE-OWN-EXINTR-BUSY*))))
      (PROG1 (DO ((K 1 (1+ K)))
		 ((NOT (EXINTR-MESSAGE-READYP))
		  NIL)
	       (EXINTR)
	       (COND ((KP-READYP KP)
		      (RETURN (INCF *HANDLE-OWN-EXINTR-WINS*)))
		     ((= K 3)
		      (RETURN NIL))))
	     (SETQ *EXINTR-IN-PROCESS* NIL))))

(DEFUN BUSY-TIME ()
  (LET ((OFFSET (+ (MSG-OFFSET (RMSG-AREA-LASTR RMSGAREA)) MESSAGES-STATUS))
	(MASK (LOGIOR MQ-DONE MQ-EXOS)))
    (LET ((X (TIME:MICROSECOND-TIME)))
      (DO ((J 0 (1+ J)))
	  ((OR (ZEROP (LOGAND MASK (AREF *DMA* OFFSET)))
	       (= J *HANDLE-OWN-EXINTR-BUSY*))))
      (- (TIME:MICROSECOND-TIME) X))))

;;; we know that about 25 process switches per second of the kind we need.
;; that is 66 milliseconds. A count of 100 is only 5 miliseconds.

(DEFUN BUSY-TIME-TEST ()
  (FORMAT T "~&COUNT milliseconds used~%")
  (DOTIMES (J 10)
    (LET ((*HANDLE-OWN-EXINTR-BUSY* (* J 30)))
      (FORMAT T "~4D ~$~%" *HANDLE-OWN-EXINTR-BUSY* (QUOTIENT (BUSY-TIME) 1000.0)))))