OpenRTX/lib/miosix-kernel/miosix/kernel/scheduler/tick_interrupt.h

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/***************************************************************************
* Copyright (C) 2010 by Terraneo Federico *
* *
* 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. *
* *
* As a special exception, if other files instantiate templates or use *
* macros or inline functions from this file, or you compile this file *
* and link it with other works to produce a work based on this file, *
* this file does not by itself cause the resulting work to be covered *
* by the GNU General Public License. However the source code for this *
* file must still be made available in accordance with the GNU General *
* Public License. This exception does not invalidate any other reasons *
* why a work based on this file might be covered by the GNU General *
* Public License. *
* *
* You should have received a copy of the GNU General Public License *
* along with this program; if not, see <http://www.gnu.org/licenses/> *
***************************************************************************/
#ifndef TICK_INTERRUPT_H
#define TICK_INTERRUPT_H
#include "config/miosix_settings.h"
#include "scheduler.h"
namespace miosix {
//These are a couple of global variables and a function that are part of the
//internal implementation of the kernel and are defined in kernel.cpp
//User code should not know about these nor try to use them.
extern volatile int kernel_running;///\internal Do not use outside the kernel
extern volatile bool tick_skew;///\internal Do not use outside the kernel
extern volatile Thread *cur;///\internal Do not use outside the kernel
extern bool IRQwakeThreads();///\internal Do not use outside the kernel
inline void IRQtickInterrupt()
{
bool woken=IRQwakeThreads();//Increment tick and wake threads,if any
(void)woken; //Avoid unused variable warning.
#ifdef SCHED_TYPE_PRIORITY
//With the priority scheduler every tick causes a context switck
Scheduler::IRQfindNextThread();//If the kernel is running, preempt
if(kernel_running!=0) tick_skew=true;
#elif defined(SCHED_TYPE_CONTROL_BASED)
//Normally, with the control based scheduler, preemptions do not happen
//here, but in the auxiliary timer interrupt to take into account variable
//bursts. But there is one exception: when a thread wakes up from sleep
//and the idle thread is running.
if(woken && cur==ControlScheduler::IRQgetIdleThread())
{
Scheduler::IRQfindNextThread();
if(kernel_running!=0) tick_skew=true;
}
#elif defined(SCHED_TYPE_EDF)
//With the EDF scheduler a preemption happens only if a thread with a closer
//deadline appears. So by deafult there is no need to call the scheduler;
//only if some threads were woken, they may have closer deadlines
if(woken)
{
Scheduler::IRQfindNextThread();
if(kernel_running!=0) tick_skew=true;
}
#endif
}
}
#endif //TICK_INTERRUPT_H