usr/src/sys/hp/dev/hil_subr.c

/*-
 * Copyright (c) 1988 University of Utah.
 * Copyright (c) 1982, 1986, 1991 The Regents of the University of California.
 * All rights reserved.
 *
 * %sccs.include.proprietary.c%
 *
 * from: Utah $Hdr: hil_subr.c 1.1 91/11/19$
 *
 *      @(#)hil_subr.c  7.1 (Berkeley) %G%
 */

#include "sys/param.h"
#include "sys/ioctl.h"
#include "sys/tty.h"
#include "sys/clist.h"

#include "hilreg.h"

/*
 * XXX this file only exists to separate out the AT&T tainted code.
 */

/*
 * This is just a copy of the virgin q_to_b routine with minor
 * optimizations for HIL use.  It is used because we don't have
 * to raise the priority to spltty() for most of the clist manipulations.
 */
hilq_to_b(q, cp, cc)
        register struct clist *q;
        register char *cp;
{
        register struct cblock *bp;
        register int nc;
        char *acp;
        int s;
        extern char cwaiting;

        if (cc <= 0)
                return (0);
        s = splhil();
        if (q->c_cc <= 0) {
                q->c_cc = 0;
                q->c_cf = q->c_cl = NULL;
                splx(s);
                return (0);
        }
        acp = cp;

        while (cc) {
                nc = sizeof (struct cblock) - ((int)q->c_cf & CROUND);
                nc = MIN(nc, cc);
                nc = MIN(nc, q->c_cc);
                (void) bcopy(q->c_cf, cp, (unsigned)nc);
                q->c_cf += nc;
                q->c_cc -= nc;
                cc -= nc;
                cp += nc;
                if (q->c_cc <= 0) {
                        bp = (struct cblock *)(q->c_cf - 1);
                        bp = (struct cblock *)((int)bp & ~CROUND);
                        q->c_cf = q->c_cl = NULL;
                        spltty();
                        bp->c_next = cfreelist;
                        cfreelist = bp;
                        cfreecount += CBSIZE;
                        if (cwaiting) {
                                wakeup(&cwaiting);
                                cwaiting = 0;
                        }
                        break;
                }
                if (((int)q->c_cf & CROUND) == 0) {
                        bp = (struct cblock *)(q->c_cf);
                        bp--;
                        q->c_cf = bp->c_next->c_info;
                        spltty();
                        bp->c_next = cfreelist;
                        cfreelist = bp;
                        cfreecount += CBSIZE;
                        if (cwaiting) {
                                wakeup(&cwaiting);
                                cwaiting = 0;
                        }
                        splhil();
                }
        }
        splx(s);
        return (cp-acp);
}