// file: tasks.c
/* 任务延时列表 */
static List_t xDelayedTaskList1;
static List_t xDelayedTaskList2;
static List_t *volatile pxDelayedTaskList;
static List_t *volatile pxOverflowDelayedTaskList;

void prvInitialiseTaskLists(void)
{// 其他操作vListInitializeList(&xDelayedTaskList1);vListInitializeList(&xDelayedTaskList2);pxDelayedTaskList = &xDelayedTaskList1;pxOverflowDelayedTaskList = &xDelayedTaskList2;
}

// file: tasks.c
/* 下一任务解锁时间 */
static volatile TickType_t xNestTaskUnblockTime = (TickType_t)0U;/* 溢出次数计数器 */
static volatile BaseType_t xNumOfOverflows = (BaseType_t)0U;

// file: tasks.c
/* 阻塞延时函数 */
void vTaskDelay(const TickType_t xTicksToDelay)
{TCB_t *pxTCB;/* 获取当前任务TCB */pxTCB = pxCurrentTCB;/* 将任务插入延时列表 */prvAddCurrentTaskToDelayedList(xTicksToDelay);/* 主动放弃CPU */taskYIELD();
}static void prvAddCurrentTaskToDelayedList(TickType_t xTicksToWait)
{TickType_t xTimeToWake;const TickType_t xConstTickCount = xTickCount;/* 将任务从就绪列表移除 */if (uxListRemove(&(pxCurrentTCB->xStateListItem)) ==(UBaseType_t)0){/* * 当该优先级就绪列表为空时，注销该优先级* 该特点用于支持同优先级多任务*/portRESET_READY_PRIORITY(pxCurrentTCB->uxPriority,uxTopReadyPriority);}/* 计算任务到期的绝对时间并设置列表项 */xTimeToWake = xConstTickCount + xTicksToWait;listSET_LIST_ITEM_VALUE(&(pxCurrentTCB->xStateListItem),xTimeToWake);/* 处理延时溢出 */if (xTimeToWake < xConstTickCount){/* 如果延时溢出，将任务按升序加入溢出延时列表 */vListInsert(pxOverflowDelayedTaskList,&(pxCurrentTCB->xStateListItem));}else{/* 如果延时未溢出，将任务按升序加入延时列表 */vListInsert(pxDelayedTaskList,&(pxCurrentTCB->xStateListItem));/* 更新下一任务解锁时间 */if (xTimeToWake < xNestTaskUnblockTime){xNestTaskUnblockTime = xTimeToWake;}}
}

// file: tasks.c
/* 更新时基函数 */
void xTaskIncrementTick(void)
{TCB_t *pxTCB = NULL;TickType_t xItemValue;/* 更新时基 */const TickType_t xConstTickCount = xTickCount + 1;xTickCount = xConstTickCount;/* 处理系统计时溢出，交换延时列表指针 */if (xConstTickCount == (TickType_t)0U){taskSWITCH_DELAYED_LISTS();}/* 处理到期的任务 */if (xConstTickCount >= xNestTaskUnblockTime){for (;;){if (listLIST_IS_EMPTY(pxDelayedTaskList) != pdFALSE){/* * 延时列表为空，将xNesTaskUnblockTime置为最大计时值* 说明此时没有任务处于延时等待状态（溢出延时列表除外）*/xNestTaskUnblockTime = portMAX_DELAY;break;}else{/* 延时列表不为空，唤醒所有到期任务 */pxTCB = (TCB_t *)listGET_OWNER_OF_HEAD_ENTRY(pxDelayedTaskList);xItemValue = listGET_LIST_ITEM_VALUE(&(pxTCB->xStateListItem));/** 遍历到无需唤醒的任务* 根据该任务的唤醒绝对时间更新下一任务解锁时间*/if (xConstTickCount < xItemValue){xNestTaskUnblockTime = xItemValue;break;}/* 将任务从延时列表移除 */uxListRemove(&(pxTCB->xStateListItem));/* 将任务加入就绪列表 */prvAddTaskToReadyList(pxTCB);}}}/* 触发任务切换 */portYIELD();
}/* 计时溢出时，交换任务延时列表指针 */
#define taskSWITCH_DELAYED_LISTS() \
{ \List_t *pxTemp; \pxTemp = pxDelayedTaskList; \pxDelayedTaskList = pxOverflowDelayedTaskList; \pxOverflowDelayedTaskList = pxTemp; \xNumOfOverflows++; \prvResetNextTaskUnblockTime(); \
}/* 交换任务延时列表后，根据交换后的列表更新下一任务解锁时间 */
static void prvResetNextTaskUnblockTime(void)
{TCB_t *pxTCB;if (listLIST_IS_EMPTY(pxDelayedTaskList) != pdFALSE){/* 当前延时列表为空，将xNextTaskUnblockTime设置为最大计时值 */xNestTaskUnblockTime = portMAX_DELAY;}else{/* 当前延时列表不为空，使用第一个延时任务设置NextTaskUnblockTime */pxTCB = (TCB_t *)listGET_OWNER_OF_HEAD_ENTRY(pxDelayedTaskList);xNestTaskUnblockTime = listGET_LIST_ITEM_VALUE(&(pxTCB->xStateListItem));}
}