基于STC8的最小操作系统

#include "stc8h.h" #include "intrins.h" #define MAX_TASKS 2 #define MAX_TASK_DEP 32 unsigned char idata task_sp[MAX_TASKS]; //任务的堆栈指针，简化方便我们当前操作系统只有2个task unsigned char idata task_stack[MAX_TASKS][MAX_TASK_DEP];//每一个task任务的堆栈 unsigned char task_id;//当前任务号，从0开始 typedef enum{ TASK_RUNNING,//运行状态 TASK_SUSPENDED//挂起状态 }TaskStatus; typedef struct{ unsigned char id;//任务id TaskStatus status;//任务状态 unsigned int delay_count;//延迟计算器 unsigned int delay_duration;//延迟时间 }Task; Task idata tasks[MAX_TASKS] = { {0,TASK_RUNNING,0,0}, {1,TASK_RUNNING,0,0},//两个任务都是默认运行状态 }; void Timer0_init(void);//原型函数 void sleep(unsigned int,unsigned int); void sleep(unsigned int task_id,unsigned int delay_ms) { tasks[task_id].status = TASK_SUSPENDED; tasks[task_id].delay_count = 0; tasks[task_id].delay_duration = delay_ms; } void Timer0_init(void)//定时1ms中断 { AUXR |=0x80; TMOD &=0xF0; TL0 = 0x40; TH0 = 0xA2; TF0 = 0; TR0 = 1; } //void Delay1000ms() //@24.000MHz //{ // unsigned char i, j, k; // _nop_(); // _nop_(); // i = 122; // j = 193; // k = 128; // do // { // do // { // while (--k); // } while (--j); // } while (--i); //} //定义一个任务切换的函数(任务调度器) void task_switch() { task_sp[task_id]=SP; task_id++; if(task_id ==MAX_TASKS) { task_id=0; } SP=task_sp[task_id]; } void task0()//第0号任务 { // static unsigned int a=3; P5M0=0x00; P5M1=0x00; P53=1; while(1) { // a=a+3; if(tasks[0].status == TASK_SUSPENDED) { task_switch(); continue; } sleep(0,1000); P53=~P53; task_switch(); } } void task1()//第1号任务 { static unsigned int b=5; while(1) { if(tasks[1].status == TASK_SUSPENDED) { task_switch(); continue; } sleep(1,1000); b=b+5; task_switch(); } } void Timer0_ISR(void) interrupt 1 { unsigned char i; for(i=0;i<MAX_TASKS;i++) { if(tasks[i].status == TASK_SUSPENDED) { tasks[i].delay_count++; } if(tasks[i].delay_count>=tasks[i].delay_duration) { tasks[i].status = TASK_RUNNING;//睡眠结束 tasks[i].delay_count=0; } } } //fn是一个函数指针，注意数据类型是int //tid_task id 是8位的， 0，1 //下面函数作用是将一个task的函数指针放入对应的堆栈空间里面 void task_load(unsigned int fn,unsigned char tid)//加载任务 { task_sp[tid]=task_stack[tid]+1; task_stack[tid][0]=fn&0xff; task_stack[tid][1]=fn>>8; } void main() { Timer0_init(); task_load(task0,0);//把task0装载入内存 task_load(task1,1);//把task1装载入内存 task_id=0; SP=task_sp[0]; }