text: #ifndef __LIST_H
  #define __LIST_H
  
  /* This file is from Linux Kernel (include/linux/list.h) 
   * and modified by simply removing hardware prefetching of list items. 
   * Here by copyright, credits attributed to wherever they belong.
   * Kulesh Shanmugasundaram (kulesh [squiggly] isis.poly.edu)
   */
  
  /*
   * Simple doubly linked list implementation.
   *
   * Some of the internal functions ("__xxx") are useful when
   * manipulating whole lists rather than single entries, as
   * sometimes we already know the next/prev entries and we can
   * generate better code by using them directly rather than
   * using the generic single-entry routines.
   */
  
  struct list_head {
  	struct list_head *next, *prev;
  };
  
  #define LIST_HEAD_INIT(name) { &(name), &(name) }
  
  #define LIST_HEAD(name) \
  	struct list_head name = LIST_HEAD_INIT(name)
  
  #define INIT_LIST_HEAD(ptr) do { \
  	(ptr)->next = (ptr); (ptr)->prev = (ptr); \
  } while (0)
  
  /*
   * Insert a new entry between two known consecutive entries. 
   *
   * This is only for internal list manipulation where we know
   * the prev/next entries already!
   */
  static inline void __list_add(struct list_head *newt,
  			      struct list_head *prev,
  			      struct list_head *next)
  {
  	next->prev = newt;
  	newt->next = next;
  	newt->prev = prev;
  	prev->next = newt;
  }
  
  /**
   * list_add - add a new entry
   * @new: new entry to be added
   * @head: list head to add it after
   *
   * Insert a new entry after the specified head.
   * This is good for implementing stacks.
   */
  static inline void list_add(struct list_head *newt, struct list_head *head)
  {
  	__list_add(newt, head, head->next);
  }
  
  /**
   * list_add_tail - add a new entry
   * @new: new entry to be added
   * @head: list head to add it before
   *
   * Insert a new entry before the specified head.
   * This is useful for implementing queues.
   */
  static inline void list_add_tail(struct list_head *newt, struct list_head *head)
  {
  	__list_add(newt, head->prev, head);
  }
  
  /*
   * Delete a list entry by making the prev/next entries
   * point to each other.
   *
   * This is only for internal list manipulation where we know
   * the prev/next entries already!
   */
  static inline void __list_del(struct list_head *prev, struct list_head *next)
  {
  	next->prev = prev;
  	prev->next = next;
  }
  
  /**
   * list_del - deletes entry from list.
   * @entry: the element to delete from the list.
   * Note: list_empty on entry does not return true after this, the entry is in an undefined state.
   */
  static inline void list_del(struct list_head *entry)
  {
  	__list_del(entry->prev, entry->next);
  	entry->next = (struct list_head *) 0;
  	entry->prev = (struct list_head *) 0;
  }
  
  /**
   * list_del_init - deletes entry from list and reinitialize it.
   * @entry: the element to delete from the list.
   */
  static inline void list_del_init(struct list_head *entry)
  {
  	__list_del(entry->prev, entry->next);
  	INIT_LIST_HEAD(entry); 
  }
  
  /**
   * list_move - delete from one list and add as another's head
   * @list: the entry to move
   * @head: the head that will precede our entry
   */
  static inline void list_move(struct list_head *list, struct list_head *head)
  {
          __list_del(list->prev, list->next);
          list_add(list, head);
  }
  
  /**
   * list_move_tail - delete from one list and add as another's tail
   * @list: the entry to move
   * @head: the head that will follow our entry
   */
  static inline void list_move_tail(struct list_head *list,
  				  struct list_head *head)
  {
          __list_del(list->prev, list->next);
          list_add_tail(list, head);
  }
  
  /**
   * list_empty - tests whether a list is empty
   * @head: the list to test.
   */
  static inline int list_empty(struct list_head *head)
  {
  	return head->next == head;
  }
  
  static inline void __list_splice(struct list_head *list,
  				 struct list_head *head)
  {
  	struct list_head *first = list->next;
  	struct list_head *last = list->prev;
  	struct list_head *at = head->next;
  
  	first->prev = head;
  	head->next = first;
  
  	last->next = at;
  	at->prev = last;
  }
  
  /**
   * list_splice - join two lists
   * @list: the new list to add.
   * @head: the place to add it in the first list.
   */
  static inline void list_splice(struct list_head *list, struct list_head *head)
  {
  	if (!list_empty(list))
  		__list_splice(list, head);
  }
  
  /**
   * list_splice_init - join two lists and reinitialise the emptied list.
   * @list: the new list to add.
   * @head: the place to add it in the first list.
   *
   * The list at @list is reinitialised
   */
  static inline void list_splice_init(struct list_head *list,
  				    struct list_head *head)
  {
  	if (!list_empty(list)) {
  		__list_splice(list, head);
  		INIT_LIST_HEAD(list);
  	}
  }
  
  /**
   * list_entry - get the struct for this entry
   * @ptr:	the &struct list_head pointer.
   * @type:	the type of the struct this is embedded in.
   * @member:	the name of the list_struct within the struct.
   */
  #define list_entry(ptr, type, member) \
  	((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))
  
  /**
   * list_for_each	-	iterate over a list
   * @pos:	the &struct list_head to use as a loop counter.
   * @head:	the head for your list.
   */
  #define list_for_each(pos, head) \
  	for (pos = (head)->next; pos != (head); \
          	pos = pos->next)
  /**
   * list_for_each_prev	-	iterate over a list backwards
   * @pos:	the &struct list_head to use as a loop counter.
   * @head:	the head for your list.
   */
  #define list_for_each_prev(pos, head) \
  	for (pos = (head)->prev; pos != (head); \
          	pos = pos->prev)
          	
  /**
   * list_for_each_safe	-	iterate over a list safe against removal of list entry
   * @pos:	the &struct list_head to use as a loop counter.
   * @n:		another &struct list_head to use as temporary storage
   * @head:	the head for your list.
   */
  #define list_for_each_safe(pos, n, head) \
  	for (pos = (head)->next, n = pos->next; pos != (head); \
  		pos = n, n = pos->next)
  
  /**
   * list_for_each_entry	-	iterate over list of given type
   * @pos:	the type * to use as a loop counter.
   * @head:	the head for your list.
   * @member:	the name of the list_struct within the struct.
   */
  #define list_for_each_entry(pos, head, member)				\
  	for (pos = list_entry((head)->next, typeof(*pos), member);	\
  	     &pos->member != (head); 					\
  	     pos = list_entry(pos->member.next, typeof(*pos), member))
  
  /**
   * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
   * @pos:	the type * to use as a loop counter.
   * @n:		another type * to use as temporary storage
   * @head:	the head for your list.
   * @member:	the name of the list_struct within the struct.
   */
  #define list_for_each_entry_safe(pos, n, head, member)			\
  	for (pos = list_entry((head)->next, typeof(*pos), member),	\
  		n = list_entry(pos->member.next, typeof(*pos), member);	\
  	     &pos->member != (head); 					\
  	     pos = n, n = list_entry(n->member.next, typeof(*n), member))
  
  
  #endif
  