rt_Robin.c

00001 /*----------------------------------------------------------------------------
00002  *      RL-ARM - RTX
00003  *----------------------------------------------------------------------------
00004  *      Name:    RT_ROBIN.C
00005  *      Purpose: Round Robin Task switching
00006  *      Rev.:    V4.60
00007  *----------------------------------------------------------------------------
00008  *
00009  * Copyright (c) 1999-2009 KEIL, 2009-2012 ARM Germany GmbH
00010  * All rights reserved.
00011  * Redistribution and use in source and binary forms, with or without
00012  * modification, are permitted provided that the following conditions are met:
00013  *  - Redistributions of source code must retain the above copyright
00014  *    notice, this list of conditions and the following disclaimer.
00015  *  - Redistributions in binary form must reproduce the above copyright
00016  *    notice, this list of conditions and the following disclaimer in the
00017  *    documentation and/or other materials provided with the distribution.
00018  *  - Neither the name of ARM  nor the names of its contributors may be used 
00019  *    to endorse or promote products derived from this software without 
00020  *    specific prior written permission.
00021  *
00022  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
00023  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
00024  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
00025  * ARE DISCLAIMED. IN NO EVENT SHALL COPYRIGHT HOLDERS AND CONTRIBUTORS BE
00026  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
00027  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
00028  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
00029  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
00030  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
00031  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
00032  * POSSIBILITY OF SUCH DAMAGE.
00033  *---------------------------------------------------------------------------*/
00034 
00035 #include "rt_TypeDef.h"
00036 #include "RTX_Conf.h"
00037 #include "rt_List.h"
00038 #include "rt_Task.h"
00039 #include "rt_Time.h"
00040 #include "rt_Robin.h"
00041 #include "rt_HAL_CM.h"
00042 
00043 /*----------------------------------------------------------------------------
00044  *      Global Variables
00045  *---------------------------------------------------------------------------*/
00046 
00047 struct OS_ROBIN os_robin;
00048 
00049 
00050 /*----------------------------------------------------------------------------
00051  *      Global Functions
00052  *---------------------------------------------------------------------------*/
00053 
00054 /*--------------------------- rt_init_robin ---------------------------------*/
00055 
00056 __weak void rt_init_robin (void) {
00057   /* Initialize Round Robin variables. */
00058   os_robin.task = NULL;
00059   os_robin.tout = (U16)os_rrobin;
00060 }
00061 
00062 /*--------------------------- rt_chk_robin ----------------------------------*/
00063 
00064 __weak void rt_chk_robin (void) {
00065   /* Check if Round Robin timeout expired and switch to the next ready task.*/
00066   P_TCB p_new;
00067 
00068   if (os_robin.task != os_rdy.p_lnk) {
00069     /* New task was suspended, reset Round Robin timeout. */
00070     os_robin.task = os_rdy.p_lnk;
00071     os_robin.time = (U16)os_time + os_robin.tout - 1;
00072   }
00073   if (os_robin.time == (U16)os_time) {
00074     /* Round Robin timeout has expired, swap Robin tasks. */
00075     os_robin.task = NULL;
00076     p_new = rt_get_first (&os_rdy);
00077     rt_put_prio ((P_XCB)&os_rdy, p_new);
00078   }
00079 }
00080 
00081 /*----------------------------------------------------------------------------
00082  * end of file
00083  *---------------------------------------------------------------------------*/
00084