/* semreset.c - semreset */

#include 

/*------------------------------------------------------------------------
 *  semreset  -  Reset a semaphore's count and release waiting processes
 *------------------------------------------------------------------------
 */
syscall semreset(
          sid32         sem,            /* ID of semaphore to reset     */
          int32         count           /* New count (must be >= 0)     */
        )
{
        intmask mask;                   /* Saved interrupt mask         */
        struct  sentry *semptr;         /* Ptr to semaphore table entry */
        qid16   semqueue;               /* Semaphore's process queue ID */
        pid32   pid;                    /* ID of a waiting process      */

        mask = disable();

        if (count < 0 || isbadsem(sem) || semtab[sem].sstate==S_FREE) {
                restore(mask);
                return SYSERR;
        }
        
        semptr = &semtab[sem];
        semqueue = semptr->squeue;      /* Free any waiting processes */
        resched_cntl(DEFER_START);
        while ((pid=getfirst(semqueue)) != EMPTY)
                ready(pid);
        semptr->scount = count;         /* Reset count as specified */
        resched_cntl(DEFER_STOP);
        restore(mask);
        return OK;
}