任务控制块是任务管理的核心数据结构，操作系统在启动的时候，首先要在内存中创建一定数量的任务控制块。
以下是OS_TCB的数据结构：
1 typedef struct os_tcb { 2 OS_STK *OSTCBStkPtr; /* Pointer to current top of stack */ 3 4 #if OS_TASK_CREATE_EXT_EN > 0u 5 void *OSTCBExtPtr; /* Pointer to user definable data for TCB extension */ 6 OS_STK *OSTCBStkBottom; /* Pointer to bottom of stack */ 7 INT32U OSTCBStkSize; /* Size of task stack (in number of stack elements) */ 8 INT16U OSTCBOpt; /* Task options as passed by OSTaskCreateExt() */ 9 INT16U OSTCBId; /* Task ID (0..65535) */ 10 #endif 11 12 struct os_tcb *OSTCBNext; /* Pointer to next TCB in the TCB list */ 13 struct os_tcb *OSTCBPrev; /* Pointer to previous TCB in the TCB list */ 14 15 #if (OS_EVENT_EN) 16 OS_EVENT *OSTCBEventPtr; /* Pointer to event control block */ 17 #endif 18 19 #if (OS_EVENT_EN) && (OS_EVENT_MULTI_EN > 0u) 20 OS_EVENT **OSTCBEventMultiPtr; /* Pointer to multiple event control blocks */ 21 #endif 22 23 #if ((OS_Q_EN > 0u) && (OS_MAX_QS > 0u)) || (OS_MBOX_EN > 0u) 24 void *OSTCBMsg; /* Message received from OSMboxPost() or OSQPost() */ 25 #endif 26 27 #if (OS_FLAG_EN > 0u) && (OS_MAX_FLAGS > 0u) 28 #if OS_TASK_DEL_EN > 0u 29 OS_FLAG_NODE *OSTCBFlagNode; /* Pointer to event flag node */ 30 #endif 31 OS_FLAGS OSTCBFlagsRdy; /* Event flags that made task ready to run */ 32 #endif 33 34 INT32U OSTCBDly; /* Nbr ticks to delay task or, timeout waiting for event */ 35 INT8U OSTCBStat; /* Task status */ 36 INT8U OSTCBStatPend; /* Task PEND status */ 37 INT8U OSTCBPrio; /* Task priority (0 == highest) */ 38 39 INT8U OSTCBX; /* Bit position in group corresponding to task priority */ 40 INT8U OSTCBY; /* Index into ready table corresponding to task priority */ 41 OS_PRIO OSTCBBitX; /* Bit mask to access bit position in ready table */ 42 OS_PRIO OSTCBBitY; /* Bit mask to access bit position in ready group */ 43 44 #if OS_TASK_DEL_EN > 0u 45 INT8U OSTCBDelReq; /* Indicates whether a task needs to delete itself */ 46 #endif 47 48 #if OS_TASK_PROFILE_EN > 0u 49 INT32U OSTCBCtxSwCtr; /* Number of time the task was switched in */ 50 INT32U OSTCBCyclesTot; /* Total number of clock cycles the task has been running */ 51 INT32U OSTCBCyclesStart; /* Snapshot of cycle counter at start of task resumption */ 52 OS_STK *OSTCBStkBase; /* Pointer to the beginning of the task stack */ 53 INT32U OSTCBStkUsed; /* Number of bytes used from the stack */ 54 #endif 55 56 #if OS_TASK_NAME_EN > 0u 57 INT8U *OSTCBTaskName; 58 #endif 59 60 #if OS_TASK_REG_TBL_SIZE > 0u 61 INT32U OSTCBRegTbl[OS_TASK_REG_TBL_SIZE]; 62 #endif 63 } OS_TCB;