Coherent4.2.10/conf/tty/src/clist.c

/* $Header: /ker/coh.386/RCS/clist.c,v 2.3 93/08/19 03:26:21 nigel Exp Locker: nigel $ */
/* (lgl-
 *	The information contained herein is a trade secret of Mark Williams
 *	Company, and  is confidential information.  It is provided  under a
 *	license agreement,  and may be  copied or disclosed  only under the
 *	terms of  that agreement.  Any  reproduction or disclosure  of this
 *	material without the express written authorization of Mark Williams
 *	Company or persuant to the license agreement is unlawful.
 *
 *	COHERENT Version 5.0
 *	Copyright (c) 1982, 1983, 1984, 1993.
 *	An unpublished work by Mark Williams Company, Chicago.
 *	All rights reserved.
 -lgl) */
/*
 * Character list management.
 *
 * $Log:	clist.c,v $
 * Revision 2.3  93/08/19  03:26:21  nigel
 * Nigel's r83 (Stylistic cleanup)
 */

#define	_KERNEL		1

#include <kernel/trace.h>
#include <kernel/param.h>
#include <sys/clist.h>
#include <sys/sched.h>

#define	cvirt(p)	((CLIST *)(p))

static int	cltwant;
static cmap_t	cltfree;

int nclfree = 0;

caddr_t		 clistp;	/* Base of clists */


/*
 * Initialise character list queues.
 *
 * Clist are not mapped.
 */
cltinit()
{
	register cmap_t cm;
	register cmap_t lm;
	register paddr_t p;
	register int s;

	s = sphi();
	lm = 0;
	p = clistp + NCLIST * sizeof (CLIST);

	while ((p -= sizeof (CLIST)) >= clistp) {
		cm = p;
		cvirt(cm)->cl_fp = lm;
		lm = cm;
	}
	cltfree = lm;

	nclfree = NCLIST;

	spl (s);
}

/*
 * Get a character from the given queue.
 */
cltgetq(cqp)
register CQUEUE *cqp;
{
	register cmap_t op;
	register cmap_t np;
	register int ox;
	register int c;
	register int s;

	if (cqp->cq_cc == 0)
		return (-1);
	s = sphi();
	op = cqp->cq_op;
	ox = cqp->cq_ox;
	c = cvirt(op)->cl_ch[ox]&0377;
	if (--cqp->cq_cc==0 || ++cqp->cq_ox==NCPCL) {
		cqp->cq_ox = 0;
		np = cvirt(op)->cl_fp;
		cvirt(op)->cl_fp = cltfree;
		cqp->cq_op = np;
		cltfree = op;
		if (np == 0) {
			cqp->cq_ip = 0;
			cqp->cq_ix = 0;
		}
		if (cltwant) {
			cltwant = 0;
			wakeup((char *)&cltwant);
		}

		nclfree++;

	}
	spl(s);
	return (c);
}

/*
 * Put a character on the given queue.
 */
cltputq(cqp, c)
register CQUEUE *cqp;
{
	register cmap_t ip;
	register int ix;
	register int s;
	register cmap_t np;

	s = sphi();
	ip = cqp->cq_ip;
	if ((ix=cqp->cq_ix) == 0) {
		if ((ip=cltfree) == 0) {
			spl(s);
			return (-1);
		}
		cltfree = cvirt(ip)->cl_fp;
		cvirt(ip)->cl_fp = 0;
		if ((np=cqp->cq_ip) == 0)
			cqp->cq_op = ip;
		else {
			cvirt(np)->cl_fp = ip;
		}
		cqp->cq_ip = ip;
		nclfree--;
	}
	cvirt(ip)->cl_ch[ix] = c;
	if (++cqp->cq_ix == NCPCL)
		cqp->cq_ix = 0;
	cqp->cq_cc++;
	spl(s);
	return c;
}

/*
 * Clear a character queue.
 */
clrq(cqp)
register CQUEUE *cqp;
{
	register int s;

	s = sphi();
	while (cltgetq(cqp) >= 0)
		;
	spl(s);
}

/*
 * Wait for more character queues to become available.
 */
waitq()
{
	while (cltfree == 0) {
		T_HAL(0x0080, putchar('+'));
		cltwant = 1;
		x_sleep((char *)&cltwant, pritty, slpriNoSig, "waitq");
		/* Wait for more character queues to become available.  */
	}
}