/* chprio.c - chprio */

#include 

/*------------------------------------------------------------------------
 *  chprio  -  Change the scheduling priority of a process
 *------------------------------------------------------------------------
 */
syscall chprio(
          pid32         pid,            /* ID of process to change      */
          pri16         newprio         /* New priority                 */
        )
{
        intmask mask;                   /* Saved interrupt mask         */
        struct  procent *prptr;         /* Ptr to process's table entry */
        pri16   oldprio;                /* Priority to return           */

        mask = disable();
        if (isbadpid(pid)) {
                restore(mask);
                return SYSERR;
        }
        prptr = &proctab[pid];
        oldprio = prptr->prprio;
        prptr->prprio = newprio;
        restore(mask);
        return 0xffff & oldprio;
}