16位单片机多任务调度器1.12版：小小调度器

#include <stc89c51.h>

/****小小调度器开始**********************************************/
#define MAXTASKS 3
volatile unsigned short timers[MAXTASKS];
#define _SS static unsigned char _lc=0; switch(_lc){default: 
#define _EE ;}; _lc=0; return 65535;

#define WaitX(tickets)  do { _lc=(__LINE__%255)+1; return (tickets) ;case (__LINE__%255)+1:;} while(0)
#define WaitUntil(A)    do { while(!(A)) WaitX(1);} while(0)
#define WaitUtilT(A,TimeOut)  do { static unsigned short _count=(TimeOut); do { WaitX(1); _count--; } while((!(A))&&(_count>0));} while(0)

#define RunTask(TaskName,TaskID)    {if (timers[TaskID]==0) { unsigned short d=TaskName(); while(timers[TaskID]!=d) timers[TaskID]=d;}}
#define RunTaskA(TaskName,TaskID)   {if (timers[TaskID]==0) {unsigned short d=TaskName(); while(timers[TaskID]!=d) timers[TaskID]=d; continue;}}   

#define CallSub(SubTaskName) do {unsigned short currdt; _lc=(__LINE__%255)+1; return 0; case (__LINE__%255)+1:  currdt=SubTaskName(); if(currdt!=65535) return currdt;} while(0)
#define InitTasks() do {unsigned char i; for(i=MAXTASKS;i>0 ;i--) timers[i-1]=0; } while(0)
#define UpdateTimers() do{unsigned char i; for(i=MAXTASKS;i>0 ;i--){if((timers[i-1]!=0)&&(timers[i-1]!=65535)) timers[i-1]--;}} while(0)

#define SEM unsigned int 
//初始化信号量
#define InitSem(sem) do{sem=0;}while(0)
//等待信号量
#define WaitSem(sem) do{ sem=1; WaitX(0); if (sem>0) return 1;} while(0)
//发送信号量
#define SendSem(sem)  do {sem=0;} while(0)

/*****小小调度器结束*******************************************************/