source: buchla-68k/orig/MT/MTID.C

/*
   =============================================================================
        mtid.c -- Multi-Tasker -- get next task ID
        Version 1 -- 1988-04-11 -- D.N. Lynx Crowe
        (c) Copyright 1988 -- D.N. Lynx Crowe
   =============================================================================
*/

#include "stddefs.h"
#include "biosdefs.h"
#include "mtdefs.h"
#include "debug.h"

extern  short           setipl();       /* set processor IPL function */

extern  struct _mtdef   *_MT_;          /* Multi-Tasker structure pointer */

/* 

*/

/*
   =============================================================================
        MTID() -- return next available task identifier
   =============================================================================
*/

unsigned
MTID()
{
        register short inuse, oldipl;
        register unsigned newtid;
        register TCB *tcp;

        inuse = TRUE;                   /* preset inuse to get things started */

        if ((struct _mt_def *)NIL EQ _MT_)
                _MT_ = (struct _mt_def *)XBIOS(X_MTDEFS);

        oldipl = setipl(7);             /* DISABLE INTERRUPTS */

        while (inuse) {

                newtid = _MT_->mtp->IDct++;     /* pick the next ID to try */
                inuse = FALSE;          /* say it's not in use */
                tcp = _MT_->mtp->TCBs;  /* start search at beginning */

                while (tcp) {           /* search the TCB table */

                        if (tcp->flags & MTF_OCC)               /* TCB occupied ? */
                                if (tcp->tid EQ newtid) {       /* tid in use ? */

                                        inuse = TRUE;   /* set to search again */
                                        break;
                                }

                        tcp = tcp->fwd;
                }
        }

        setipl(oldipl);                 /* RESTORE INTERRUPTS */

        return(newtid);                 /* return the new task ID */
}