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/*
 * Project: S.Ha.R.K.
 *
 * Coordinators:
 *   Giorgio Buttazzo    <giorgio@sssup.it>
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *
 * Authors     :
 *   Paolo Gai           <pj@gandalf.sssup.it>
 *   Massimiliano Giorgi <massy@gandalf.sssup.it>
 *   Luca Abeni          <luca@gandalf.sssup.it>
 *   (see the web pages for full authors list)
 *
 * ReTiS Lab (Scuola Superiore S.Anna - Pisa - Italy)
 *
 * http://www.sssup.it
 * http://retis.sssup.it
 * http://shark.sssup.it
 */


/**
 ------------
 CVS :        $Id: rrsoft.h,v 1.3 2003-03-13 13:39:05 pj Exp $

 File:        $File$
 Revision:    $Revision: 1.3 $
 Last update: $Date: 2003-03-13 13:39:05 $
 ------------

 This file contains the scheduling module RRSOFT (Round Robin for
 Hard & Soft Model)

 Title:
   RRSOFT (Round Robin) version 1

 Task Models Accepted:
   NRT_TASK_MODEL - Non-Realtime Tasks
     weight field is ignored
     slice  field is used to set the slice of a task, if it is !=0
     policy field is ignored
     inherit field is ignored
   SOFT_TASK_MODEL - Soft tasks
     only the periodicity and the met are used.
   HARD_TASK_MODEL - Hard tasks
     only the periodicity and the period are used.


 Description:
   This module schedule his tasks following the classic round-robin
   scheme. The default timeslice is given at registration time and is a
   a per-task specification. The default timeslice is used if the slice
   field in the NRT_TASK_MODEL is 0.

   The module can SAVE or SKIP activations
   There is another module, RR, thar always SKIP activations...

   The Module is derived from the RRSOFT, and it accepts only one
   kind of task Model (hard, soft or nrt).

 Exceptions raised:
   XUNVALID_GUEST
     This level doesn't support guests. When a guest operation
     is called, the exception is raised.

 Restrictions & special features:
   - if specified, it creates at init time a task,
     called "Main", attached to the function __init__().
   - There must be only one module in the system that creates a task
     attached to the function __init__().
   - The level tries to guarantee that a task uses a "full" timeslice
     before going to the queue tail. "full" means that a task can execute
     a maximum time of slice+sys_tick due to the approx. done by
     the Virtual Machine. If a task execute more time than the slice,
     the next time it execute less...

**/

/*
 * Copyright (C) 2000 Paolo Gai
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */


#ifndef __RRSOFT_H__
#define __RRSOFT_H__

#include <ll/ll.h>
#include <kernel/config.h>
#include <sys/types.h>
#include <kernel/types.h>
#include "ll/sys/cdefs.h"

__BEGIN_DECLS

extern TASK __init__(void *arg);



/*+ Const: +*/
#define RRSOFT_MINIMUM_SLICE      1000 /*+ Minimum Timeslice +*/
#define RRSOFT_MAXIMUM_SLICE    500000 /*+ Maximum Timeslice +*/

#define RRSOFT_MAIN_YES              1 /*+ The level creates the main +*/
#define RRSOFT_MAIN_NO               0 /*+ The level does'nt create the main +*/

#define RRSOFT_ONLY_HARD             1 /*+ The level accepts only Hard Tasks +*/
#define RRSOFT_ONLY_SOFT             2 /*+ The level accepts only Soft Tasks +*/
#define RRSOFT_ONLY_NRT              4 /*+ The level accepts only NRT  Tasks +*/


/*+ Registration function:
    TIME slice                the slice for the Round Robin queue
    int createmain            1 if the level creates the main task 0 otherwise
    struct multiboot_info *mb used if createmain specified  

    returns the level number at which the module has been registered.
+*/

LEVEL RRSOFT_register_level(TIME slice,
                           int createmain,
                           struct multiboot_info *mb,
                           BYTE models);

__END_DECLS
#endif