建立一个AVR的RTOS（6）时间片轮番调度法的内核

latile__("POP R30 \n\t");

__asm__ __volatile__("POP R27 \n\t");

__asm__ __volatile__("POP R26 \n\t");

__asm__ __volatile__("POP R25 \n\t");

__asm__ __volatile__("POP R24 \n\t");

__asm__ __volatile__("POP R23 \n\t");

__asm__ __volatile__("POP R22 \n\t");

__asm__ __volatile__("POP R21 \n\t");

__asm__ __volatile__("POP R20 \n\t");

__asm__ __volatile__("POP R19 \n\t");

__asm__ __volatile__("POP R18 \n\t");

__asm__ __volatile__("POP __tmp_reg__ \n\t"); //SERG出栈并恢复

__asm__ __volatile__("OUT __SREG__,__tmp_reg__ \n\t"); //

__asm__ __volatile__("POP __tmp_reg__ \n\t"); //R0出栈

__asm__ __volatile__("POP __zero_reg__ \n\t"); //R1出栈

__asm__ __volatile__("RETI \n\t"); //返回并开中断

//中断时出栈完成

}

void IntSwitch(void)

{

__asm__ __volatile__("POP R31 \n\t"); //去除因调用子程序而入栈的PC

__asm__ __volatile__("POP R31 \n\t");

__asm__ __volatile__("RJMP Int_OSSched \n\t"); //重新调度

}

void TCN0Init(void) //计时器0

{

TCCR0 = 0;

TCCR0 |= (1

TIMSK |= (1

TCNT0 = 100; //置计数起始值

}

SIGNAL(SIG_OVERFLOW0)

{

TCNT0=100;

IntSwitch(); //任务调度

}

void Task0()

{

unsigned int j=0;

while(1)

{

PORTB=j++;

//OSTimeDly(50);

}

}

void Task1()

{

unsigned int j=0;

while(1)

{

PORTC=j++;

//OSTimeDly(5);

}

}

void Task2()

{

unsigned int j=0;

while(1)

{

PORTD=j++;

//OSTimeDly(5);

}

}

void TaskScheduler()

{

while(1)

{

OSSched(); //反复进行调度

}

}

int main(void)

{

TCN0Init();

OSRdyTbl=0;

OSTaskCreate(Task0,&Stack[99],0);

OSTaskCreate(Task1,&Stack[199],1);

OSTaskCreate(Task2,&Stack[299],2);

OSTaskCreate(TaskScheduler,&Stack[399],OS_TASKS);

OSStartTask();

}