Source to bsd/netat/adsp_TimerElem.c

/*
 * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * "Portions Copyright (c) 1999 Apple Computer, Inc.  All Rights
 * Reserved.  This file contains Original Code and/or Modifications of
 * Original Code as defined in and that are subject to the Apple Public
 * Source License Version 1.0 (the 'License').  You may not use this file
 * except in compliance with the License.  Please obtain a copy of the
 * License at http://www.apple.com/publicsource and read it before using
 * this file.
 * 
 * The Original Code and all software distributed under the License are
 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License."
 * 
 * @APPLE_LICENSE_HEADER_END@
 */


#include <adsp_local.h>
atlock_t adsptmr_lock;

extern	void DoTimerElem();	/* (TimerElemPtr t);  
				 * External routine called to 
				 * process each one. */

/*
 * InsertTimerElem
 * 
 * INPUTS:
 * 	qhead		Address of ptr to first item in list
 *	t		timer element to link in
 *	vbl		timer value to use
 * OUTPUTS:
 * 	void
 */
void InsertTimerElem(qhead, t, val)
    /* (TimerElemPtr *qhead, TimerElemPtr t, word val) */
    TimerElemPtr *qhead, t;
    int val;
{
    TimerElemPtr p;		/* parent pointer */
    TimerElemPtr n;		/* current */
    int	s;
	
    ATDISABLE(s, adsptmr_lock);
	
    if (t->onQ) {
        /*
	 * someone else beat us to the punch and put this
	 * element back on the queue, just return in this case
	 */
        ATENABLE(s, adsptmr_lock);
	return;
    }
    p = (TimerElemPtr)qhead;

    while (n = p->link) {
	if (val <= n->timer)	/* Do we go in front of this? */
	{
	    n->timer -= val;	/* Yes, adjust his delta */
	    break;		/* and go link us in */
	}
	val -= n->timer;	/* No, subtract off delta from our value */
	p = n;
    }				/* while */
	
    /* It must go after item pointed to by p and in front of item 
     * pointed to by n */

    t->onQ = 1;	/* we're linked in now */
    p->link = t;		/* parent points to us */
    t->timer = val;		/* this is our value */
    t->link = n;		/* we point to n */
    
    ATENABLE(s, adsptmr_lock);
}


/*
 * RemoveTimerElem
 * 
 * INPUTS:
 *	qhead		Address of ptr to first item in list
 *	t		timer element to link in
 * OUTPUTS:
 * 	void
 */
void RemoveTimerElem(qhead, t)	/* (TimerElemPtr *qhead, TimerElemPtr t) */
    TimerElemPtr *qhead, t;
{
    TimerElemPtr p;		/* parent pointer */
    TimerElemPtr n;		/* current */
    int	s;
	
    ATDISABLE(s, adsptmr_lock);
	
    if ( !t->onQ) {
        /*
	 * someone else beat us to the punch and took this
	 * element off of the queue, just return in this case
	 */
        ATENABLE(s, adsptmr_lock);
	return;
    }
    p = (TimerElemPtr)qhead;

    while (n = p->link)	/* Get next item in queue */
    {
	if (n == t)		/* Is it us? */
	{
	    if (p->link = n->link) /* Link our parent to our child */
	    {
		n->link->timer += t->timer; /* and update child's timer */
	    }
	    n->onQ = 0;		/* Not on linked list anymore */
	    break;
	}
	p = n;
    }				/* while */
	
    ATENABLE(s, adsptmr_lock);
}


/*
 * TimerQueueTick
 * 
 * INPUTS:
 * 	qhead		Address of ptr to first item in list
 * 	
 * OUTPUTS:
 * 	void
 */
void TimerQueueTick(qhead)	/* (TimerElemPtr *qhead) */
    TimerElemPtr *qhead;
{
    TimerElemPtr p;		/* parent pointer */
    TimerElemPtr n;		/* current */
    int	s;
	
    ATDISABLE(s, adsptmr_lock);
	
    p = (TimerElemPtr)qhead;
    if (p->link)		/* Is anything on queue? */
	p->link->timer--;	/* Yes, decrement by a tick */
    else
	goto done;		/* No, we're outta' here */
		
    while ((n = p->link) && 
	   (n->timer == 0)) /* Next guy needs to be serviced */
    {
	p->link = n->link;	/* Unlink us */
	n->onQ	= 0;

	ATENABLE(s, adsptmr_lock);
	DoTimerElem(n);
	ATDISABLE(s, adsptmr_lock);

	p = (TimerElemPtr)qhead;
    }				/* while */
	
done:
    ATENABLE(s, adsptmr_lock);
}