add API (tos_task_create_dyn & tos_task_walkthru & tos_task_curr_task_get)

tos_task_create_dyn: create task with dynamic allocated task handler and stack
tos_task_walkthru: API to walk through the statistic list of all the existing task
tos_task_curr_task_get: get current running task handler

kernel/core/include/tos_sem.h

@@ -23,8 +23,24 @@
 typedef struct k_sem_st {
     pend_obj_t      pend_obj;
     k_sem_cnt_t     count;
+    k_sem_cnt_t     count_max;
 } k_sem_t;
 
+/**
+ * @brief Create a semaphore with a limitation of maximum count.
+ * create a semaphore with a limitation of maximum count.
+ *
+ * @attention None
+ *
+ * @param[in]   sem         pointer to the handler of the semaphore.
+ * @param[in]   init_count  initial count of the semaphore.
+ * @param[in]   max_count   maximum count of the semaphore.
+ *
+ * @return  errcode
+ * @retval  #K_ERR_NONE                   return successfully.
+ */
+__API__ k_err_t tos_sem_create_max(k_sem_t *sem, k_sem_cnt_t init_count, k_sem_cnt_t max_count);
+
 /**
  * @brief Create a semaphore.
  * create a semaphore.
@@ -32,6 +48,7 @@ typedef struct k_sem_st {
  * @attention None
  *
  * @param[in]   sem         pointer to the handler of the semaphore.
+ * @param[in]   init_count  initial count of the semaphore.
  *
  * @return  errcode
  * @retval  #K_ERR_NONE                   return successfully.