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

/*
   =============================================================================
        mtzap.c -- Multi-Tasker -- free a TCB
        Version 3 -- 1988-04-14 -- 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 */

/* 

*/

/*
   =============================================================================
        MTZap() -- delete a task  (free its TCB)

                -1      not deleted     (was active or waiting)
                 0      deleted
                 1      not found
   =============================================================================
*/

short
MTZap(tid)
unsigned tid;
{
        register short oldipl, rv;
        register TCB *tcp;

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

        tcp = _MT_->mtp->TCBs;          /* point at start of TCB table */
        rv = 1;                         /* preset return code */

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

        while (tcp) {                   /* check each TCB */

                if (tcp->flags & MTF_OCC) {     /* occupied ? */

                        if (tcp->tid NE tid)    /* continue if not TCB we want */
                                goto nexttcb;

                        if (tcp->flags & ~MTF_OCC) {    /* stopped ? */

                                rv = -1;        /* not stopped */
                                break;
                        }

                        tcp->flags = 0;         /* free the TCB */
                        rv = 0;                 /* TCB deleted */
                        break;
                }

nexttcb:
                tcp = tcp->fwd;                 /* check next TCB */
        }

        setipl(oldipl);                 /* RESTORE INTERRUPTS */

        return(rv);                     /* return deletion status */
}