/* ttycontrol.c - ttycontrol */

#include 

/*------------------------------------------------------------------------
 *  ttycontrol  -  Control a tty device by setting modes
 *------------------------------------------------------------------------
 */
devcall ttycontrol(
          struct dentry *devptr,        /* Entry in device switch table */
          int32  func,                  /* Function to perform          */
          int32  arg1,                  /* Argument 1 for request       */
          int32  arg2                   /* Argument 2 for request       */
        )
{
        struct  ttycblk *typtr;         /* Pointer to tty control block */
        char    ch;                     /* Character for lookahead      */

        typtr = &ttytab[devptr->dvminor];

        /* Process the request */

        switch ( func ) {

        case TC_NEXTC:
                wait(typtr->tyisem);
                ch = *typtr->tyitail;
                signal(typtr->tyisem);
                return (devcall)(0xff & ch);

        case TC_MODER:
                typtr->tyimode = TY_IMRAW;
                return (devcall)OK;

        case TC_MODEC:
                typtr->tyimode = TY_IMCOOKED;
                return (devcall)OK;

        case TC_MODEK:
                typtr->tyimode = TY_IMCBREAK;
                return (devcall)OK;

        case TC_ICHARS:
                return(semcount(typtr->tyisem));

        case TC_ECHO:
                typtr->tyiecho = TRUE;
                return (devcall)OK;

        case TC_NOECHO:
                typtr->tyiecho = FALSE;
                return (devcall)OK;

        default:
                return (devcall)SYSERR;
        }
}