/*
*********************************************************************************************************
* uC/OS-II
* The Real-Time Kernel
* CORE FUNCTIONS
*
* (c) Copyright 1992-2002, Jean J. Labrosse, Weston, FL
* All Rights Reserved
*
* File : OS_CORE.C
* By : Jean J. Labrosse
*********************************************************************************************************
*/
#ifndef OS_MASTER_FILE
#define OS_GLOBALS
#include "includes.h"
#endif
/*
*********************************************************************************************************
* MAPPING TABLE TO MAP BIT POSITION TO BIT MASK
*
* Note: Index into table is desired bit position, 0..7
* Indexed value corresponds to bit mask
*********************************************************************************************************
*/
//任务进行就绪状态
INT8U const OSMapTbl[] = {0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80};
/*
*********************************************************************************************************
* PRIORITY RESOLUTION TABLE
*
* Note: Index into table is bit pattern to resolve highest priority
* Indexed value corresponds to highest priority bit position (i.e. 0..7)
*********************************************************************************************************
*/
//为了提高查询优先级数组的数组--就是为x--与y做准备 查找高优先级做方便
INT8U const OSUnMapTbl[] = {
0, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x00 to 0x0F */
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x10 to 0x1F */
5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x20 to 0x2F */
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x30 to 0x3F */
6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x40 to 0x4F */
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x50 to 0x5F */
5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x60 to 0x6F */
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x70 to 0x7F */
7, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x80 to 0x8F */
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0x90 to 0x9F */
5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0xA0 to 0xAF */
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0xB0 to 0xBF */
6, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0xC0 to 0xCF */
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0xD0 to 0xDF */
5, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0, /* 0xE0 to 0xEF */
4, 0, 1, 0, 2, 0, 1, 0, 3, 0, 1, 0, 2, 0, 1, 0 /* 0xF0 to 0xFF */
};
/*
*********************************************************************************************************
* FUNCTION PROTOTYPES
*********************************************************************************************************
*/
//初始化事件控制块缓冲池，与上面初始化任务控制块缓冲池类似，但移植手册没详细介绍
static void OS_InitEventList(void);
static void OS_InitMisc(void);
static void OS_InitRdyList(void);
static void OS_InitTaskIdle(void);
static void OS_InitTaskStat(void);
static void OS_InitTCBList(void);//初始化任务控制块--空
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZATION
*
* Description: This function is used to initialize the internals of uC/OS-II and MUST be called prior to
* creating any uC/OS-II object and, prior to calling OSStart().
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//初始化uc/os-II
void OSInit (void) /*1 第一步:初始化UC/OS-II */
{
#if OS_VERSION >= 204
// 2 这个函数的原因在于，想把与OS有关的初始化代码也放在OSInit()函数中。这个函数由用户自己编写，此程序中为空函数。
//钩子函数
OSInitHookBegin(); /* Call port specific initialization code */
#endif
//初始化各种变量
OS_InitMisc(); /* Initialize miscellaneous variables */
//初始化就绪链表
OS_InitRdyList(); /* Initialize the Ready List */
//初始化任务控制块NULL
OS_InitTCBList(); /* Initialize the free list of OS_TCBs */
//初始化事件表
OS_InitEventList(); /* Initialize the free list of OS_EVENTs */
#if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0)
OS_FlagInit();//初始化标志控制块缓冲池 /* Initialize the event flag structures */
#endif
#if (OS_MEM_EN > 0) && (OS_MAX_MEM_PART > 0)
//初始化内存
OS_MemInit(); /* Initialize the memory manager */
#endif
#if (OS_Q_EN > 0) && (OS_MAX_QS > 0)
//初始化消息队列
OS_QInit(); /* Initialize the message queue structures */
#endif
//初始化空闲任务
OS_InitTaskIdle(); /* Create the Idle Task */
#if OS_TASK_STAT_EN > 0
//初始够统计任务
OS_InitTaskStat(); /* Create the Statistic Task */
#endif
#if OS_VERSION >= 204
//空函数
OSInitHookEnd(); /* Call port specific init. code */
#endif
}
/*$PAGE*/
/*
*********************************************************************************************************
* ENTER ISR
*
* Description: This function is used to notify uC/OS-II that you are about to service an interrupt
* service routine (ISR). This allows uC/OS-II to keep track of interrupt nesting and thus
* only perform rescheduling at the last nested ISR.
*
* Arguments : none
*
* Returns : none
*
* Notes : 1) This function should be called ith interrupts already disabled
* 2) Your ISR can directly increment OSIntNesting without calling this function because
* OSIntNesting has been declared 'global'.
* 3) You MUST still call OSIntExit() even though you increment OSIntNesting directly.
* 4) You MUST invoke OSIntEnter() and OSIntExit() in pair. In other words, for every call
* to OSIntEnter() at the beginning of the ISR you MUST have a call to OSIntExit() at the
* end of the ISR.
* 5) You are allowed to nest interrupts up to 255 levels deep.
* 6) I removed the OS_ENTER_CRITICAL() and OS_EXIT_CRITICAL() around the increment because
* OSIntEnter() is always called with interrupts disabled.
*********************************************************************************************************
*/
//把全局变量 OSIntNesting++ 进入中断函数
void OSIntEnter (void)
{
//是否多任务状态
if (OSRunning == TRUE) {
if (OSIntNesting < 255) {
//增加中断嵌套层数
OSIntNesting++; /* Increment ISR nesting level */
}
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* EXIT ISR
*
* Description: This function is used to notify uC/OS-II that you have completed serviving an ISR. When
* the last nested ISR has completed, uC/OS-II will call the scheduler to determine whether
* a new, high-priority task, is ready to run.
*
* Arguments : none
*
* Returns : none
*
* Notes : 1) You MUST invoke OSIntEnter() and OSIntExit() in pair. In other words, for every call
* to OSIntEnter() at the beginning of the ISR you MUST have a call to OSIntExit() at the
* end of the ISR.
* 2) Rescheduling is prevented when the scheduler is locked (see OS_SchedLock())
*********************************************************************************************************
*/
//退出中断函数
void OSIntExit (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
//是否在多任务运行
if (OSRunning == TRUE) {
OS_ENTER_CRITICAL();
//是否在嵌套函数
if (OSIntNesting > 0) { /* Prevent OSIntNesting from wrapping */
OSIntNesting--;
}
if ((OSIntNesting == 0) && (OSLockNesting == 0)) { /* Reschedule only if all ISRs complete ... */
//从就绪表中获取最高的就绪任务
OSIntExitY = OSUnMapTbl[OSRdyGrp]; /* ... and not locked. */
OSPrioHighRdy = (INT8U)((OSIntExitY << 3) + OSUnMapTbl[OSRdyTbl[OSIntExitY]]);
//判断当前最高级优先任务
if (OSPrioHighRdy != OSPrioCur) { /* No Ctx Sw if current task is highest rdy */
//改变就绪标志
OSTCBHighRdy = OSTCBPrioTbl[OSPrioHighRdy];
//任务切换的数++
OSCtxSwCtr++; /* Keep track of the number of ctx switches */
//进行中断级的任务切换
OSIntCtxSw(); /* Perform interrupt level ctx switch */
}
}
OS_EXIT_CRITICAL();
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* PREVENT SCHEDULING
*
* Description: This function is used to prevent rescheduling to take place. This allows your application
* to prevent context switches until you are ready to permit context switching.
*
* Arguments : none
*
* Returns : none
*
* Notes : 1) You MUST invoke OSSchedLock() and OSSchedUnlock() in pair. In other words, for every
* call to OSSchedLock() you MUST have a call to OSSchedUnlock().
*********************************************************************************************************
*/
//实现任务上锁
#if OS_SCHED_LOCK_EN > 0
void OSSchedLock (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
//是否在多任务
if (OSRunning == TRUE) { /* Make sure multitasking is running */
OS_ENTER_CRITICAL();
if (OSLockNesting < 255) { /* Prevent OSLockNesting from wrapping back to 0 */
//给任务加锁
OSLockNesting++; /* Increment lock nesting level */
}
OS_EXIT_CRITICAL();
}
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* ENABLE SCHEDULING
*
* Description: This function is used to re-allow rescheduling.
*
* Arguments : none
*
* Returns : none
*
* Notes : 1) You MUST invoke OSSchedLock() and OSSchedUnlock() in pair. In other words, for every
* call to OSSchedLock() you MUST have a call to OSSchedUnlock().
*********************************************************************************************************
*/
//给任务解锁
#if OS_SCHED_LOCK_EN > 0
void OSSchedUnlock (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
//是否在多任务
if (OSRunning == TRUE) { /* Make sure multitasking is running */
OS_ENTER_CRITICAL();
//是否在嵌套函数中
if (OSLockNesting > 0) { /* Do not decrement if already 0 */
OSLockNesting--; /* Decrement lock nesting level */
//检查任务是否在中断--是否被锁住
if ((OSLockNesting == 0) && (OSIntNesting == 0)) { /* See if sched. enabled and not an ISR */
OS_EXIT_CRITICAL();
//进行一次任务调度
OS_Sched(); /* See if a HPT is ready */
} else {
OS_EXIT_CRITICAL();
}
} else {
OS_EXIT_CRITICAL();
}
}
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* START MULTITASKING
*
* Description: This function is used to start the multitasking process which lets uC/OS-II manages the
* task that you have created. Before you can call OSStart(), you MUST have called OSInit()
* and you MUST have created at least one task.
*
* Arguments : none
*
* Returns : none
*
* Note : OSStartHighRdy() MUST:
* a) Call OSTaskSwHook() then,
* b) Set OSRunning to TRUE.
* c) Load the context of the task pointed to by OSTCBHighRdy.
* d_ Execute the task.
*********************************************************************************************************
*/
//os开启 --lets uC/OS-II manages the task that you have created.
void OSStart (void)
{
INT8U y;
INT8U x;
//不是在多任务
if (OSRunning == FALSE) {
//在就绪表中获取优先级最高的任务
y = OSUnMapTbl[OSRdyGrp]; /* Find highest priority's task priority number */
x = OSUnMapTbl[OSRdyTbl[y]];
OSPrioHighRdy = (INT8U)((y << 3) + x);
OSPrioCur = OSPrioHighRdy; //修改当前的优先级
OSTCBHighRdy = OSTCBPrioTbl[OSPrioHighRdy]; /* Point to highest priority task ready to run */
OSTCBCur = OSTCBHighRdy;
//运行最高优先级的任务
OSStartHighRdy(); /* Execute target specific code to start task */
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* STATISTICS INITIALIZATION
*
* Description: This function is called by your application to establish CPU usage by first determining
* how high a 32-bit counter would count to in 1 second if no other tasks were to execute
* during that time. CPU usage is then determined by a low priority task which keeps track
* of this 32-bit counter every second but this time, with other tasks running. CPU usage is
* determined by:
*
* OSIdleCtr
* CPU Usage (%) = 100 * (1 - ------------)
* OSIdleCtrMax
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//os的初始化
#if OS_TASK_STAT_EN > 0
void OSStatInit (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
OSTimeDly(2); /* Synchronize with clock tick */
OS_ENTER_CRITICAL();
OSIdleCtr = 0L; /* Clear idle counter */
OS_EXIT_CRITICAL();
OSTimeDly(OS_TICKS_PER_SEC); /* Determine MAX. idle counter value for 1 second */
OS_ENTER_CRITICAL();
OSIdleCtrMax = OSIdleCtr; /* Store maximum idle counter count in 1 second */
OSStatRdy = TRUE;
OS_EXIT_CRITICAL();
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* PROCESS SYSTEM TICK
*
* Description: This function is used to signal to uC/OS-II the occurrence of a 'system tick' (also known
* as a 'clock tick'). This function should be called by the ticker ISR but, can also be
* called by a high priority task.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//时钟节拍服务函数 --是在发生中断时 调用
void OSTimeTick (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
OS_TCB *ptcb;
OSTimeTickHook(); /* Call user definable hook */
#if OS_TIME_GET_SET_EN > 0
OS_ENTER_CRITICAL(); /* Update the 32-bit tick counter */
//记录节拍数
OSTime++;
OS_EXIT_CRITICAL();
#endif
if (OSRunning == TRUE) {
ptcb = OSTCBList; /* Point at first TCB in TCB list */
while (ptcb->OSTCBPrio != OS_IDLE_PRIO) { /* Go through all TCBs in TCB list */
OS_ENTER_CRITICAL();
if (ptcb->OSTCBDly != 0) { /* Delayed or waiting for event with TO */
if (--ptcb->OSTCBDly == 0) { /* Decrement nbr of ticks to end of delay */
/* Is task suspended? 如果任务不是被挂起*/
if ((ptcb->OSTCBStat & OS_STAT_SUSPEND) == OS_STAT_RDY) { /* Is task suspended? */
//直接给就绪组和就绪表给标志让任务就绪
OSRdyGrp |= ptcb->OSTCBBitY; /* No, Make task R-to-R (timed out)*/
OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
} else { /* Yes, Leave 1 tick to prevent ... */
//loosing the task time
ptcb->OSTCBDly = 1; /* ... loosing the task when the ... */
} /* ... suspension is removed. */
}
}
//判断下一块
ptcb = ptcb->OSTCBNext; /* Point at next TCB in TCB list */
OS_EXIT_CRITICAL();
}
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* GET VERSION
*
* Description: This function is used to return the version number of uC/OS-II. The returned value
* corresponds to uC/OS-II's version number multiplied by 100. In other words, version 2.00
* would be returned as 200.
*
* Arguments : none
*
* Returns : the version number of uC/OS-II multiplied by 100.
*********************************************************************************************************
*/
INT16U OSVersion (void)
{
return (OS_VERSION);
}
/*$PAGE*/
/*
*********************************************************************************************************
* DUMMY FUNCTION
*
* Description: This function doesn't do anything. It is called by OSTaskDel().
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//啥也不做 --OSTaskDel
#if OS_TASK_DEL_EN > 0
void OS_Dummy (void)
{
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* MAKE TASK READY TO RUN BASED ON EVENT OCCURING
*
* Description: This function is called by other uC/OS-II services and is used to ready a task that was
* waiting for an event to occur.
*
* Arguments : pevent is a pointer to the event control block corresponding to the event.
*
* msg is a pointer to a message. This pointer is used by message oriented services
* such as MAILBOXEs and QUEUEs. The pointer is not used when called by other
* service functions.
*
* msk is a mask that is used to clear the status byte of the TCB. For example,
* OSSemPost() will pass OS_STAT_SEM, OSMboxPost() will pass OS_STAT_MBOX etc.
*
* Returns : none
*
* Note : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/
//is used to ready a task that was waiting for an event to occur.
#if OS_EVENT_EN > 0
INT8U OS_EventTaskRdy (OS_EVENT *pevent, void *msg, INT8U msk)
{
OS_TCB *ptcb;
INT8U x;
INT8U y;
INT8U bitx;
INT8U bity;
INT8U prio;
//找到最高优先级的等待任务的优先级
y = OSUnMapTbl[pevent->OSEventGrp]; /* Find highest prio. task waiting for message */
bity = OSMapTbl[y];
x = OSUnMapTbl[pevent->OSEventTbl[y]];
bitx = OSMapTbl[x];
prio = (INT8U)((y << 3) + x); /* Find priority of task getting the msg */
// Remove this task from the waiting list
if ((pevent->OSEventTbl[y] &= ~bitx) == 0x00) { /* Remove this task from the waiting list */
pevent->OSEventGrp &= ~bity; /* Clr group bit if this was only task pending */
}
//改变任务控制块
ptcb = OSTCBPrioTbl[prio]; /* Point to this task's OS_TCB */
ptcb->OSTCBDly = 0; /* Prevent OSTimeTick() from readying task */
ptcb->OSTCBEventPtr = (OS_EVENT *)0; /* Unlink ECB from this task */
#if ((OS_Q_EN > 0) && (OS_MAX_QS > 0)) || (OS_MBOX_EN > 0)
ptcb->OSTCBMsg = msg; /* Send message directly to waiting task */
#else
// Prevent compiler warning if not used
msg = msg; /* Prevent compiler warning if not used */
#endif
ptcb->OSTCBStat &= ~msk; /* Clear bit associated with event type */
// See if task is ready (could be susp'd
if (ptcb->OSTCBStat == OS_STAT_RDY) { /* See if task is ready (could be susp'd) */
//使得任务就绪
OSRdyGrp |= bity; /* Put task in the ready to run list */
OSRdyTbl[y] |= bitx;
}
return (prio);
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* MAKE TASK WAIT FOR EVENT TO OCCUR
*
* Description: This function is called by other uC/OS-II services to suspend a task because an event has
* not occurred.
*
* Arguments : pevent is a pointer to the event control block for which the task will be waiting for.
*
* Returns : none
*
* Note : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/
//设置事件等待 pevent表示控制块的指针
#if OS_EVENT_EN > 0
void OS_EventTaskWait (OS_EVENT *pevent)
{
OSTCBCur->OSTCBEventPtr = pevent; /* Store pointer to event control block in TCB */
//判断就绪表里是否有任务在运行
if ((OSRdyTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0x00) { /* Task no longer ready */
//若没有 改变就绪组
OSRdyGrp &= ~OSTCBCur->OSTCBBitY; /* Clear event grp bit if this was only task pending */
}
//把当前的任务---在ecb等待表中添加此事件
pevent->OSEventTbl[OSTCBCur->OSTCBY] |= OSTCBCur->OSTCBBitX; /* Put task in waiting list */
//若对应的事件等待组中的对应位 没置位的话 进行置位
pevent->OSEventGrp |= OSTCBCur->OSTCBBitY;
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* MAKE TASK READY TO RUN BASED ON EVENT TIMEOUT
*
* Description: This function is called by other uC/OS-II services to make a task ready to run because a
* timeout occurred.
*
* Arguments : pevent is a pointer to the event control block which is readying a task.
*
* Returns : none
*
* Note : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/
//services to make a task ready to run because a timeout occurred.
#if OS_EVENT_EN > 0
void OS_EventTO (OS_EVENT *pevent)
{
//判断就绪表里是否有任务在运行
if ((pevent->OSEventTbl[OSTCBCur->OSTCBY] &= ~OSTCBCur->OSTCBBitX) == 0x00) {
pevent->OSEventGrp &= ~OSTCBCur->OSTCBBitY;
}
//Set status to ready
OSTCBCur->OSTCBStat = OS_STAT_RDY; /* Set status to ready */
//使得当前的事件块为0
OSTCBCur->OSTCBEventPtr = (OS_EVENT *)0; /* No longer waiting for event */
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZE EVENT CONTROL BLOCK'S WAIT LIST
*
* Description: This function is called by other uC/OS-II services to initialize the event wait list.
*
* Arguments : pevent is a pointer to the event control block allocated to the event.
*
* Returns : none
*
* Note : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/
//initialize the event wait list.
#if ((OS_Q_EN > 0) && (OS_MAX_QS > 0)) || (OS_MBOX_EN > 0) || (OS_SEM_EN > 0) || (OS_MUTEX_EN > 0)
void OS_EventWaitListInit (OS_EVENT *pevent)
{
INT8U *ptbl;
pevent->OSEventGrp = 0x00; /* No task waiting on event */
ptbl = &pevent->OSEventTbl[0];
#if OS_EVENT_TBL_SIZE > 0
*ptbl++ = 0x00;
#endif
#if OS_EVENT_TBL_SIZE > 1
*ptbl++ = 0x00;
#endif
#if OS_EVENT_TBL_SIZE > 2
*ptbl++ = 0x00;
#endif
#if OS_EVENT_TBL_SIZE > 3
*ptbl++ = 0x00;
#endif
#if OS_EVENT_TBL_SIZE > 4
*ptbl++ = 0x00;
#endif
#if OS_EVENT_TBL_SIZE > 5
*ptbl++ = 0x00;
#endif
#if OS_EVENT_TBL_SIZE > 6
*ptbl++ = 0x00;
#endif
#if OS_EVENT_TBL_SIZE > 7
*ptbl = 0x00;
#endif
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZATION
* INITIALIZE THE FREE LIST OF EVENT CONTROL BLOCKS
*
* Description: This function is called by OSInit() to initialize the free list of event control blocks.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//This function is called by OSInit() to initialize the free list of event control blocks.
static void OS_InitEventList (void)
{
#if (OS_EVENT_EN > 0) && (OS_MAX_EVENTS > 0)
#if (OS_MAX_EVENTS > 1)
INT16U i;
OS_EVENT *pevent1;
OS_EVENT *pevent2;
pevent1 = &OSEventTbl[0];
pevent2 = &OSEventTbl[1];
//Init. list of free EVENT control blocks 空链表
for (i = 0; i < (OS_MAX_EVENTS - 1); i++) { /* Init. list of free EVENT control blocks */
pevent1->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent1->OSEventPtr = pevent2;
pevent1++;
pevent2++;
}
//链表构建完成--但最后一个任务为初始化--OS_EVENT_TYPE_UNUSED=0
pevent1->OSEventType = OS_EVENT_TYPE_UNUSED;
pevent1->OSEventPtr = (OS_EVENT *)0;
OSEventFreeList = &OSEventTbl[0];
#else
OSEventFreeList = &OSEventTbl[0]; /* Only have ONE event control block */
OSEventFreeList->OSEventType = OS_EVENT_TYPE_UNUSED;
OSEventFreeList->OSEventPtr = (OS_EVENT *)0; //将表头指向链表的头部
#endif
#endif
}
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZATION
* INITIALIZE MISCELLANEOUS VARIABLES
*
* Description: This function is called by OSInit() to initialize miscellaneous variables.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//初始化各种变量
static void OS_InitMisc (void)
{
#if OS_TIME_GET_SET_EN > 0
OSTime = 0L; /* Clear the 32-bit system clock */
#endif
//interrupt nesting counter
OSIntNesting = 0; /* Clear the interrupt nesting counter */
//scheduling lock counter
OSLockNesting = 0; /* Clear the scheduling lock counter */
//the number of tasks
OSTaskCtr = 0; /* Clear the number of tasks */
//Indicate--表明multitasking not started --多任务未启动
OSRunning = FALSE; /* Indicate that multitasking not started */
//context switch counter
OSCtxSwCtr = 0; /* Clear the context switch counter */
// idle counter
OSIdleCtr = 0L; /* Clear the 32-bit idle counter */
//
#if (OS_TASK_STAT_EN > 0) && (OS_TASK_CREATE_EXT_EN > 0)
OSIdleCtrRun = 0L;
OSIdleCtrMax = 0L;
OSStatRdy = FALSE; /* Statistic task is not ready */
#endif
}
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZATION
* INITIALIZE THE READY LIST
*
* Description: This function is called by OSInit() to initialize the Ready List.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//3...初始化就绪表--initialize the Ready List.
static void OS_InitRdyList (void)
{
INT16U i;
INT8U *prdytbl;
OSRdyGrp = 0x00; /* Clear the ready list */
prdytbl = &OSRdyTbl[0];
for (i = 0; i < OS_RDY_TBL_SIZE; i++) {
*prdytbl++ = 0x00;
}
OSPrioCur = 0;
OSPrioHighRdy = 0;
OSTCBHighRdy = (OS_TCB *)0;
OSTCBCur = (OS_TCB *)0;
}
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZATION
* CREATING THE IDLE TASK
*
* Description: This function creates the Idle Task.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//creates the Idle Task.
static void OS_InitTaskIdle (void)
{
//是否裁剪
#if OS_TASK_CREATE_EXT_EN > 0
#if OS_STK_GROWTH == 1
(void)OSTaskCreateExt(OS_TaskIdle,
(void *)0, /* No arguments passed to OS_TaskIdle() */
&OSTaskIdleStk[OS_TASK_IDLE_STK_SIZE - 1], /* Set Top-Of-Stack */
OS_IDLE_PRIO, /* Lowest priority level */
OS_TASK_IDLE_ID,
&OSTaskIdleStk[0], /* Set Bottom-Of-Stack */
OS_TASK_IDLE_STK_SIZE,
(void *)0, /* No TCB extension */
OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR);/* Enable stack checking + clear stack */
#else
(void)OSTaskCreateExt(OS_TaskIdle,
(void *)0, /* No arguments passed to OS_TaskIdle() */
&OSTaskIdleStk[0], /* Set Top-Of-Stack */
OS_IDLE_PRIO, /* Lowest priority level */
OS_TASK_IDLE_ID,
&OSTaskIdleStk[OS_TASK_IDLE_STK_SIZE - 1], /* Set Bottom-Of-Stack */
OS_TASK_IDLE_STK_SIZE,
(void *)0, /* No TCB extension */
OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR);/* Enable stack checking + clear stack */
#endif
#else
#if OS_STK_GROWTH == 1
(void)OSTaskCreate(OS_TaskIdle,
(void *)0,
&OSTaskIdleStk[OS_TASK_IDLE_STK_SIZE - 1],
OS_IDLE_PRIO);
#else
(void)OSTaskCreate(OS_TaskIdle,
(void *)0,
&OSTaskIdleStk[0],
OS_IDLE_PRIO);
#endif
#endif
}
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZATION
* CREATING THE STATISTIC TASK
*
* Description: This function creates the Statistic Task.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//统计任务 creates the Statistic Task.
#if OS_TASK_STAT_EN > 0
static void OS_InitTaskStat (void)
{
#if OS_TASK_CREATE_EXT_EN > 0
#if OS_STK_GROWTH == 1
(void)OSTaskCreateExt(OS_TaskStat,
(void *)0, /* No args passed to OS_TaskStat()*/
&OSTaskStatStk[OS_TASK_STAT_STK_SIZE - 1], /* Set Top-Of-Stack */
OS_STAT_PRIO, /* One higher than the idle task */
OS_TASK_STAT_ID,
&OSTaskStatStk[0], /* Set Bottom-Of-Stack */
OS_TASK_STAT_STK_SIZE,
(void *)0, /* No TCB extension */
OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR); /* Enable stack checking + clear */
#else
(void)OSTaskCreateExt(OS_TaskStat,
(void *)0, /* No args passed to OS_TaskStat()*/
&OSTaskStatStk[0], /* Set Top-Of-Stack */
OS_STAT_PRIO, /* One higher than the idle task */
OS_TASK_STAT_ID,
&OSTaskStatStk[OS_TASK_STAT_STK_SIZE - 1], /* Set Bottom-Of-Stack */
OS_TASK_STAT_STK_SIZE,
(void *)0, /* No TCB extension */
OS_TASK_OPT_STK_CHK | OS_TASK_OPT_STK_CLR); /* Enable stack checking + clear */
#endif
#else
#if OS_STK_GROWTH == 1
(void)OSTaskCreate(OS_TaskStat,
(void *)0, /* No args passed to OS_TaskStat()*/
&OSTaskStatStk[OS_TASK_STAT_STK_SIZE - 1], /* Set Top-Of-Stack */
OS_STAT_PRIO); /* One higher than the idle task */
#else
(void)OSTaskCreate(OS_TaskStat,
(void *)0, /* No args passed to OS_TaskStat()*/
&OSTaskStatStk[0], /* Set Top-Of-Stack */
OS_STAT_PRIO); /* One higher than the idle task */
#endif
#endif
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZATION
* INITIALIZE THE FREE LIST OF TASK CONTROL BLOCKS
*
* Description: This function is called by OSInit() to initialize the free list of OS_TCBs.
*
* Arguments : none
*
* Returns : none
*********************************************************************************************************
*/
//初始化5个空的数据结构缓冲区,这里只初始化了任务控制块缓冲池和事件控制块缓冲池
static void OS_InitTCBList (void)//初始化任务控制块缓冲池
{
INT8U i;
OS_TCB *ptcb1;
OS_TCB *ptcb2;
//初始化 TCB
OSTCBList = (OS_TCB *)0; /* TCB Initialization */
//初始化就绪表
for (i = 0; i < (OS_LOWEST_PRIO + 1); i++) { /* Clear the priority table */
OSTCBPrioTbl[i] = (OS_TCB *)0;
}
ptcb1 = &OSTCBTbl[0];
ptcb2 = &OSTCBTbl[1];
//Init. list of free TCBs
for (i = 0; i < (OS_MAX_TASKS + OS_N_SYS_TASKS - 1); i++) { /* Init. list of free TCBs */
ptcb1->OSTCBNext = ptcb2;
ptcb1++;
ptcb2++;
}
//初始化最后一个tcb指针指向null
ptcb1->OSTCBNext = (OS_TCB *)0; /* Last OS_TCB */
//让OSTCBFreeList指向tcb头部
OSTCBFreeList = &OSTCBTbl[0];
}
/*$PAGE*/
/*
*********************************************************************************************************
* SCHEDULER
*
* Description: This function is called by other uC/OS-II services to determine whether a new, high
* priority task has been made ready to run. This function is invoked by TASK level code
* and is not used to reschedule tasks from ISRs (see OSIntExit() for ISR rescheduling).
*
* Arguments : none
*
* Returns : none
*
* Notes : 1) This function is INTERNAL to uC/OS-II and your application should not call it.
* 2) Rescheduling is prevented when the scheduler is locked (see OS_SchedLock())
*********************************************************************************************************
*/
//任务调度
void OS_Sched (void)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
INT8U y;
OS_ENTER_CRITICAL();
if ((OSIntNesting == 0) && (OSLockNesting == 0)) { /* Sched. only if all ISRs done & not locked */
//从就绪表中获取优先级最高的任务
y = OSUnMapTbl[OSRdyGrp]; /* Get pointer to HPT ready to run */
OSPrioHighRdy = (INT8U)((y << 3) + OSUnMapTbl[OSRdyTbl[y]]);
if (OSPrioHighRdy != OSPrioCur) { /* No Ctx Sw if current task is highest rdy */
OSTCBHighRdy = OSTCBPrioTbl[OSPrioHighRdy];
OSCtxSwCtr++; /* Increment context switch counter */
//Perform-执行一次任务切换
OS_TASK_SW(); /* Perform a context switch */
}
}
OS_EXIT_CRITICAL();
}
/*$PAGE*/
/*
*********************************************************************************************************
* IDLE TASK
*
* Description: This task is internal to uC/OS-II and executes whenever no other higher priority tasks
* executes because they are ALL waiting for event(s) to occur.
*
* Arguments : none
*
* Returns : none
*
* Note(s) : 1) OSTaskIdleHook() is called after the critical section to ensure that interrupts will be
* enabled for at least a few instructions. On some processors (ex. Philips XA), enabling
* and then disabling interrupts didn't allow the processor enough time to have interrupts
* enabled before they were disabled again. uC/OS-II would thus never recognize
* interrupts.
* 2) This hook has been added to allow you to do such things as STOP the CPU to conserve
* power.
*********************************************************************************************************
*/
//空闲任务 不能用来删除
void OS_TaskIdle (void *pdata)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
pdata = pdata; /* Prevent compiler warning for not using 'pdata' */
for (;;) {
OS_ENTER_CRITICAL();
OSIdleCtr++;
OS_EXIT_CRITICAL();
OSTaskIdleHook(); /* Call user definable HOOK */
}
}
/*$PAGE*/
/*
*********************************************************************************************************
* STATISTICS TASK
*
* Description: This task is internal to uC/OS-II and is used to compute some statistics about the
* multitasking environment. Specifically, OS_TaskStat() computes the CPU usage.
* CPU usage is determined by:
*
* OSIdleCtr
* OSCPUUsage = 100 * (1 - ------------) (units are in %)
* OSIdleCtrMax
*
* Arguments : pdata this pointer is not used at this time.
*
* Returns : none
*
* Notes : 1) This task runs at a priority level higher than the idle task. In fact, it runs at the
* next higher priority, OS_IDLE_PRIO-1.
* 2) You can disable this task by setting the configuration #define OS_TASK_STAT_EN to 0.
* 3) We delay for 5 seconds in the beginning to allow the system to reach steady state and
* have all other tasks created before we do statistics. You MUST have at least a delay
* of 2 seconds to allow for the system to establish the maximum value for the idle
* counter.
*********************************************************************************************************
*/
//统计任务----This task runs at a priority level higher than the idle task.
#if OS_TASK_STAT_EN > 0
void OS_TaskStat (void *pdata)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
INT32U run;
INT32U max;
INT8S usage;
// Prevent compiler warning for not using 'pdata'
pdata = pdata; /* Prevent compiler warning for not using 'pdata' */
while (OSStatRdy == FALSE) {
OSTimeDly(2 * OS_TICKS_PER_SEC); /* Wait until statistic task is ready */
}
max = OSIdleCtrMax / 100L;
for (;;) {
OS_ENTER_CRITICAL();
OSIdleCtrRun = OSIdleCtr; /* Obtain the of the idle counter for the past second */
run = OSIdleCtr;
OSIdleCtr = 0L; /* Reset the idle counter for the next second */
OS_EXIT_CRITICAL();
if (max > 0L) {
usage = (INT8S)(100L - run / max);
if (usage >= 0) { /* Make sure we don't have a negative percentage */
OSCPUUsage = usage;
} else {
OSCPUUsage = 0;
}
} else {
OSCPUUsage = 0;
max = OSIdleCtrMax / 100L;
}
OSTaskStatHook(); /* Invoke user definable hook */
OSTimeDly(OS_TICKS_PER_SEC); /* Accumulate OSIdleCtr for the next second */
}
}
#endif
/*$PAGE*/
/*
*********************************************************************************************************
* INITIALIZE TCB
*
* Description: This function is internal to uC/OS-II and is used to initialize a Task Control Block when
* a task is created (see OSTaskCreate() and OSTaskCreateExt()).
*
* Arguments : prio is the priority of the task being created
*
* ptos is a pointer to the task's top-of-stack assuming that the CPU registers
* have been placed on the stack. Note that the top-of-stack corresponds to a
* 'high' memory location is OS_STK_GROWTH is set to 1 and a 'low' memory
* location if OS_STK_GROWTH is set to 0. Note that stack growth is CPU
* specific.
*
* pbos is a pointer to the bottom of stack. A NULL pointer is passed if called by
* 'OSTaskCreate()'.
*
* id is the task's ID (0..65535)
*
* stk_size is the size of the stack (in 'stack units'). If the stack units are INT8Us
* then, 'stk_size' contains the number of bytes for the stack. If the stack
* units are INT32Us then, the stack contains '4 * stk_size' bytes. The stack
* units are established by the #define constant OS_STK which is CPU
* specific. 'stk_size' is 0 if called by 'OSTaskCreate()'.
*
* pext is a pointer to a user supplied memory area that is used to extend the task
* control block. This allows you to store the contents of floating-point
* registers, MMU registers or anything else you could find useful during a
* context switch. You can even assign a name to each task and store this name
* in this TCB extension. A NULL pointer is passed if called by OSTaskCreate().
*
* opt options as passed to 'OSTaskCreateExt()' or,
* 0 if called from 'OSTaskCreate()'.
*
* Returns : OS_NO_ERR if the call was successful
* OS_NO_MORE_TCB if there are no more free TCBs to be allocated and thus, the task cannot
* be created.
*
* Note : This function is INTERNAL to uC/OS-II and your application should not call it.
*********************************************************************************************************
*/
//internal-内部的 This function is internal to uC/OS-II and is used to initialize a Task Control Block when
// a task is created (see OSTaskCreate() and OSTaskCreateExt()).
INT8U OS_TCBInit (INT8U prio, OS_STK *ptos, OS_STK *pbos, INT16U id, INT32U stk_size, void *pext, INT16U opt)
{
#if OS_CRITICAL_METHOD == 3 /* Allocate storage for CPU status register */
OS_CPU_SR cpu_sr;
#endif
OS_TCB *ptcb;
OS_ENTER_CRITICAL();
//Get a free TCB from the free TCB list
ptcb = OSTCBFreeList; /* Get a free TCB from the free TCB list */
if (ptcb != (OS_TCB *)0) {
OSTCBFreeList = ptcb->OSTCBNext; /* Update pointer to free TCB list */
OS_EXIT_CRITICAL();
ptcb->OSTCBStkPtr = ptos; /* Load Stack pointer in TCB */
ptcb->OSTCBPrio = (INT8U)prio; /* Load task priority into TCB */
ptcb->OSTCBStat = OS_STAT_RDY; /* Task is ready to run */
ptcb->OSTCBDly = 0; /* Task is not delayed */
#if OS_TASK_CREATE_EXT_EN > 0
ptcb->OSTCBExtPtr = pext; /* Store pointer to TCB extension */
ptcb->OSTCBStkSize = stk_size; /* Store stack size */
ptcb->OSTCBStkBottom = pbos; /* Store pointer to bottom of stack */
ptcb->OSTCBOpt = opt; /* Store task options */
ptcb->OSTCBId = id; /* Store task ID */
#else
pext = pext; /* Prevent compiler warning if not used */
stk_size = stk_size;
pbos = pbos;
opt = opt;
id = id;
#endif
#if OS_TASK_DEL_EN > 0
ptcb->OSTCBDelReq = OS_NO_ERR;
#endif
ptcb->OSTCBY = prio >> 3; /* Pre-compute X, Y, BitX and BitY */
ptcb->OSTCBBitY = OSMapTbl[ptcb->OSTCBY];
ptcb->OSTCBX = prio & 0x07;
ptcb->OSTCBBitX = OSMapTbl[ptcb->OSTCBX];
#if OS_EVENT_EN > 0
ptcb->OSTCBEventPtr = (OS_EVENT *)0; /* Task is not pending on an event */
#endif
#if (OS_VERSION >= 251) && (OS_FLAG_EN > 0) && (OS_MAX_FLAGS > 0) && (OS_TASK_DEL_EN > 0)
ptcb->OSTCBFlagNode = (OS_FLAG_NODE *)0; /* Task is not pending on an event flag */
#endif
#if (OS_MBOX_EN > 0) || ((OS_Q_EN > 0) && (OS_MAX_QS > 0))
ptcb->OSTCBMsg = (void *)0; /* No message received */
#endif
#if OS_VERSION >= 204
OSTCBInitHook(ptcb);
#endif
//Call user defined hook
OSTaskCreateHook(ptcb); /* Call user defined hook */
OS_ENTER_CRITICAL();
OSTCBPrioTbl[prio] = ptcb;
ptcb->OSTCBNext = OSTCBList; /* Link into TCB chain */
ptcb->OSTCBPrev = (OS_TCB *)0;
if (OSTCBList != (OS_TCB *)0) {
OSTCBList->OSTCBPrev = ptcb;
}
OSTCBList = ptcb;
//让任务就绪
OSRdyGrp |= ptcb->OSTCBBitY; /* Make task ready to run */
OSRdyTbl[ptcb->OSTCBY] |= ptcb->OSTCBBitX;
OS_EXIT_CRITICAL();
return (OS_NO_ERR);
}
OS_EXIT_CRITICAL();
return (OS_NO_MORE_TCB);
}