/* mark.c - markinit, mark */

#include 

int32   *marks[MAXMARK];                /* Pointers to marked locations */
int32   nmarks;                         /* Number of marked locations   */
sid32   mkmutex;                        /* Mutual exclusion semaphore   */

/*------------------------------------------------------------------------
 *  markinit  -  Called once at system startup
 *------------------------------------------------------------------------
 */
void    markinit(void)
{
        nmarks = 0;
        mkmutex = semcreate(1);
}


/*------------------------------------------------------------------------
 *  notmarked  -  Return nonzero if a location has not been marked
 *------------------------------------------------------------------------
 */
syscall notmarked(memmark loc)
{       
        intmask mask;                   /* Saved interrupt mask         */

        mask = disable();

        /* See if the location has been marked */

        if (loc[0]<0 || loc[0]>=nmarks || marks[loc[0]] != loc) {
                restore(mask);
                return FALSE;
        }
        return TRUE;
}


/*------------------------------------------------------------------------
 *  mark  -  Mark a specified memory location
 *------------------------------------------------------------------------
 */
syscall mark(
          int32 *loc                    /* Location to mark             */
        )

{
        intmask mask;                   /* Saved interrupt mask         */

        mask = disable();

        /* If location is already marked, do nothing */

        if ( (*loc>=0) && (*loc= MAXMARK) {
                restore(mask);
                return SYSERR;
        }

        /* Obtain exclusive access and mark the specified location */

        marks[ (*loc) = nmarks++ ] = loc;
        restore(mask);
        return OK;
}