score: Create chain implementation header

Move implementation specific parts of chain.h and chain.inl into new
header file chainimpl.h.  The chain.h contains now only the application
visible API.

6 files changed, 971 insertions, 186 deletions

diff --git a/cpukit/score/include/rtems/score/apiext.h b/cpukit/score/include/rtems/score/apiext.h
index 54b8049241..d980bb1ecc 100644
--- a/cpukit/score/include/rtems/score/apiext.h
+++ b/cpukit/score/include/rtems/score/apiext.h
@@ -18,6 +18,13 @@
 #ifndef _RTEMS_SCORE_APIEXT_H
 #define _RTEMS_SCORE_APIEXT_H
 
+#include <rtems/score/chainimpl.h>
+#include <rtems/score/thread.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  *  @defgroup ScoreAPIExtension API Extension Handler
  *
@@ -32,9 +39,6 @@
  */
 /**@{*/
 
-#include <rtems/score/chain.h>
-#include <rtems/score/thread.h>
-
 #if defined(FUNCTIONALITY_NOT_CURRENTLY_USED_BY_ANY_API)
   /**
    *  This type defines the prototype of the Predriver Hook.
@@ -179,5 +183,9 @@ static inline void _API_extensions_Run_post_switch( Thread_Control *executing )
 
 /**@}*/
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif
 /* end of include file */
diff --git a/cpukit/score/include/rtems/score/chain.h b/cpukit/score/include/rtems/score/chain.h
index 4b2a449823..00f30c3082 100644
--- a/cpukit/score/include/rtems/score/chain.h
+++ b/cpukit/score/include/rtems/score/chain.h
@@ -20,6 +20,10 @@
 #ifndef _RTEMS_SCORE_CHAIN_H
 #define _RTEMS_SCORE_CHAIN_H
 
+#ifdef __cplusplus
+extern "C" {
+#endif
+
 /**
  *  @defgroup ScoreChain Chain Handler
  *
@@ -33,12 +37,6 @@
  */
 /**@{*/
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-#include <rtems/score/address.h>
-
 /**
  *  @typedef Chain_Node
  *
@@ -94,187 +92,11 @@ typedef union {
   } Tail;
 } Chain_Control;
 
-/**
- *  @brief Chain initializer for an empty chain with designator @a name.
- */
-#define CHAIN_INITIALIZER_EMPTY(name) \
-  { { { &(name).Tail.Node, NULL }, &(name).Head.Node } }
-
-/**
- *  @brief Chain definition for an empty chain with designator @a name.
- */
-#define CHAIN_DEFINE_EMPTY(name) \
-  Chain_Control name = CHAIN_INITIALIZER_EMPTY(name)
-
-/**
- *  @brief Initialize a chain header.
- *
- *  This routine initializes @a the_chain structure to manage the
- *  contiguous array of @a number_nodes nodes which starts at
- *  @a starting_address.  Each node is of @a node_size bytes.
- *
- *  @param[in] the_chain specifies the chain to initialize
- *  @param[in] starting_address is the starting address of the array
- *         of elements
- *  @param[in] number_nodes is the numebr of nodes that will be in the chain
- *  @param[in] node_size is the size of each node
- */
-void _Chain_Initialize(
-  Chain_Control *the_chain,
-  void          *starting_address,
-  size_t         number_nodes,
-  size_t         node_size
-);
-
-/**
- *  @brief Extract the specified node from a chain.
- *
- *  This routine extracts @a the_node from the chain on which it resides.
- *  It disables interrupts to ensure the atomicity of the extract operation.
- *
- *  @param[in] the_node is the node to be extracted
- *
- *  - INTERRUPT LATENCY:
- *    + single case
- */
-void _Chain_Extract(
-  Chain_Node *the_node
-);
-
-/**
- *  @brief Obtain the first node on a chain.
- *
- *  This function removes the first node from @a the_chain and returns
- *  a pointer to that node.  If @a the_chain is empty, then NULL is returned.
- *
- *  @retval This method returns a pointer a node.  If a node was removed,
- *          then a pointer to that node is returned.  If @a the_chain was
- *          empty, then NULL is returned.
- *
- *  @note It disables interrupts to ensure the atomicity of the get operation.
- */
-Chain_Node *_Chain_Get(
-  Chain_Control *the_chain
-);
-
-/**
- *  @brief Insert a node on a chain.
- *
- *  This routine inserts @a the_node on a chain immediately following
- *  @a after_node.
- *
- *  @param[in] after_node is the pointer to the node in chain to be
- *             inserted after
- *  @param[in] the_node is the pointer to the node to be inserted
- *
- *  @note It disables interrupts to ensure the atomicity
- *  of the insert operation.
- *
- *  - INTERRUPT LATENCY:
- *    + single case
- */
-void _Chain_Insert(
-  Chain_Node *after_node,
-  Chain_Node *the_node
-);
-
-/**
- *  @brief Append a node on the end of a chain.
- *
- *  This routine appends @a the_node onto the end of @a the_chain.
- *
- *  @note It disables interrupts to ensure the atomicity of the
- *  append operation.
- */
-void _Chain_Append(
-  Chain_Control *the_chain,
-  Chain_Node    *the_node
-);
-
-/**
- * @brief Append a node and check if the chain was empty before.
- *
- * This routine appends the_node onto the end of the_chain.
- *
- * @param[in] the_chain is the chain to be operated upon.
- * @param[in] the_node is the node to be appended.
- *
- * @note It disables interrupts to ensure the atomicity of the append
- * operation.
- *
- * @retval true The chain was empty before.
- * @retval false The chain contained at least one node before.
- */
-bool _Chain_Append_with_empty_check(
-  Chain_Control *the_chain,
-  Chain_Node    *the_node
-);
-
-/**
- * @brief Prepend a node and check if the chain was empty before.
- *
- * This routine prepends the_node onto the front of the_chain.
- *
- * @param[in] the_chain is the chain to be operated upon.
- * @param[in] the_node is the node to be prepended.
- *
- * @note It disables interrupts to ensure the atomicity of the append
- * operation.
- *
- * @retval true The chain was empty before.
- * @retval false The chain contained at least one node before.
- */
-bool _Chain_Prepend_with_empty_check(
-  Chain_Control *the_chain,
-  Chain_Node    *the_node
-);
-
-/**
- * @brief Get the first node and check if the chain is empty afterwards.
- *
- * This function removes the first node from the_chain and returns
- * a pointer to that node in @a the_node.  If the_chain is empty, then NULL is
- * returned.
- *
- * @param[in] the_chain is the chain to attempt to get the first node from.
- * @param[out] the_node is the first node on the chain or NULL if the chain is
- * empty.
- *
- * @note It disables interrupts to ensure the atomicity of the append
- * operation.
- *
- * @retval true The chain is empty now.
- * @retval false The chain contains at least one node now.
- *
- *  - INTERRUPT LATENCY:
- *    + single case
- */
-bool _Chain_Get_with_empty_check(
-  Chain_Control *the_chain,
-  Chain_Node **the_node
-);
-
-/**
- * @brief Returns the node count of the chain.
- *
- * @param[in] chain The chain.
- *
- * @note It does NOT disable interrupts to ensure the atomicity of the
- * operation.
- *
- * @retval The node count of the chain.
- */
-size_t _Chain_Node_count_unprotected( const Chain_Control *chain );
-
-#ifndef __RTEMS_APPLICATION__
-#include <rtems/score/chain.inl>
-#endif
+/**@}*/
 
 #ifdef __cplusplus
 }
 #endif
 
-/**@}*/
-
 #endif
 /* end of include file */
diff --git a/cpukit/score/include/rtems/score/chainimpl.h b/cpukit/score/include/rtems/score/chainimpl.h
new file mode 100644
index 0000000000..f87ce82098
--- /dev/null
+++ b/cpukit/score/include/rtems/score/chainimpl.h
@@ -0,0 +1,952 @@
+/**
+ * @file
+ *
+ * @brief Chain Handler API
+ */
+
+/*
+ *  Copyright (c) 2010 embedded brains GmbH.
+ *
+ *  COPYRIGHT (c) 1989-2006.
+ *  On-Line Applications Research Corporation (OAR).
+ *
+ *  The license and distribution terms for this file may be
+ *  found in the file LICENSE in this distribution or at
+ *  http://www.rtems.com/license/LICENSE.
+ */
+
+#ifndef _RTEMS_SCORE_CHAINIMPL_H
+#define _RTEMS_SCORE_CHAINIMPL_H
+
+#include <rtems/score/chain.h>
+#include <rtems/score/address.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @addtogroup ScoreChain
+ */
+/**@{**/
+
+/**
+ *  @brief Chain initializer for an empty chain with designator @a name.
+ */
+#define CHAIN_INITIALIZER_EMPTY(name) \
+  { { { &(name).Tail.Node, NULL }, &(name).Head.Node } }
+
+/**
+ *  @brief Chain definition for an empty chain with designator @a name.
+ */
+#define CHAIN_DEFINE_EMPTY(name) \
+  Chain_Control name = CHAIN_INITIALIZER_EMPTY(name)
+
+/**
+ *  @brief Initialize a chain header.
+ *
+ *  This routine initializes @a the_chain structure to manage the
+ *  contiguous array of @a number_nodes nodes which starts at
+ *  @a starting_address.  Each node is of @a node_size bytes.
+ *
+ *  @param[in] the_chain specifies the chain to initialize
+ *  @param[in] starting_address is the starting address of the array
+ *         of elements
+ *  @param[in] number_nodes is the numebr of nodes that will be in the chain
+ *  @param[in] node_size is the size of each node
+ */
+void _Chain_Initialize(
+  Chain_Control *the_chain,
+  void          *starting_address,
+  size_t         number_nodes,
+  size_t         node_size
+);
+
+/**
+ *  @brief Extract the specified node from a chain.
+ *
+ *  This routine extracts @a the_node from the chain on which it resides.
+ *  It disables interrupts to ensure the atomicity of the extract operation.
+ *
+ *  @param[in] the_node is the node to be extracted
+ *
+ *  - INTERRUPT LATENCY:
+ *    + single case
+ */
+void _Chain_Extract(
+  Chain_Node *the_node
+);
+
+/**
+ *  @brief Obtain the first node on a chain.
+ *
+ *  This function removes the first node from @a the_chain and returns
+ *  a pointer to that node.  If @a the_chain is empty, then NULL is returned.
+ *
+ *  @retval This method returns a pointer a node.  If a node was removed,
+ *          then a pointer to that node is returned.  If @a the_chain was
+ *          empty, then NULL is returned.
+ *
+ *  @note It disables interrupts to ensure the atomicity of the get operation.
+ */
+Chain_Node *_Chain_Get(
+  Chain_Control *the_chain
+);
+
+/**
+ *  @brief Insert a node on a chain.
+ *
+ *  This routine inserts @a the_node on a chain immediately following
+ *  @a after_node.
+ *
+ *  @param[in] after_node is the pointer to the node in chain to be
+ *             inserted after
+ *  @param[in] the_node is the pointer to the node to be inserted
+ *
+ *  @note It disables interrupts to ensure the atomicity
+ *  of the insert operation.
+ *
+ *  - INTERRUPT LATENCY:
+ *    + single case
+ */
+void _Chain_Insert(
+  Chain_Node *after_node,
+  Chain_Node *the_node
+);
+
+/**
+ *  @brief Append a node on the end of a chain.
+ *
+ *  This routine appends @a the_node onto the end of @a the_chain.
+ *
+ *  @note It disables interrupts to ensure the atomicity of the
+ *  append operation.
+ */
+void _Chain_Append(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+);
+
+/**
+ * @brief Append a node and check if the chain was empty before.
+ *
+ * This routine appends the_node onto the end of the_chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to be appended.
+ *
+ * @note It disables interrupts to ensure the atomicity of the append
+ * operation.
+ *
+ * @retval true The chain was empty before.
+ * @retval false The chain contained at least one node before.
+ */
+bool _Chain_Append_with_empty_check(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+);
+
+/**
+ * @brief Prepend a node and check if the chain was empty before.
+ *
+ * This routine prepends the_node onto the front of the_chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to be prepended.
+ *
+ * @note It disables interrupts to ensure the atomicity of the append
+ * operation.
+ *
+ * @retval true The chain was empty before.
+ * @retval false The chain contained at least one node before.
+ */
+bool _Chain_Prepend_with_empty_check(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+);
+
+/**
+ * @brief Get the first node and check if the chain is empty afterwards.
+ *
+ * This function removes the first node from the_chain and returns
+ * a pointer to that node in @a the_node.  If the_chain is empty, then NULL is
+ * returned.
+ *
+ * @param[in] the_chain is the chain to attempt to get the first node from.
+ * @param[out] the_node is the first node on the chain or NULL if the chain is
+ * empty.
+ *
+ * @note It disables interrupts to ensure the atomicity of the append
+ * operation.
+ *
+ * @retval true The chain is empty now.
+ * @retval false The chain contains at least one node now.
+ *
+ *  - INTERRUPT LATENCY:
+ *    + single case
+ */
+bool _Chain_Get_with_empty_check(
+  Chain_Control *the_chain,
+  Chain_Node **the_node
+);
+
+/**
+ * @brief Returns the node count of the chain.
+ *
+ * @param[in] chain The chain.
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity of the
+ * operation.
+ *
+ * @retval The node count of the chain.
+ */
+size_t _Chain_Node_count_unprotected( const Chain_Control *chain );
+
+/**
+ * @brief Set off chain.
+ *
+ * This function sets the next and previous fields of the @a node to NULL
+ * indicating the @a node is not part of a chain.
+ *
+ * @param[in] node the node set to off chain.
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Set_off_chain(
+  Chain_Node *node
+)
+{
+  node->next = node->previous = NULL;
+}
+
+/**
+ * @brief Is the node off chain.
+ *
+ * This function returns true if the @a node is not on a chain. A @a node is
+ * off chain if the next and previous fields are set to NULL.
+ *
+ * @param[in] node is the node off chain.
+ *
+ * @retval true The @a node is off chain.
+ * @retval false The @a node is not off chain.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Is_node_off_chain(
+  const Chain_Node *node
+)
+{
+  return (node->next == NULL) && (node->previous == NULL);
+}
+
+/**
+ * @brief Are two nodes equal.
+ *
+ * This function returns true if @a left and @a right are equal,
+ * and false otherwise.
+ *
+ * @param[in] left is the node on the left hand side of the comparison.
+ * @param[in] right is the node on the left hand side of the comparison.
+ *
+ * @retval true @a left and @a right are equal.
+ * @retval false @a left and @a right are not equal.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Are_nodes_equal(
+  const Chain_Node *left,
+  const Chain_Node *right
+)
+{
+  return left == right;
+}
+
+/**
+ * @brief Is this chain control pointer NULL.
+ *
+ * This function returns true if the_chain is NULL and false otherwise.
+ *
+ * @param[in] the_chain is the chain to be checked for empty status.
+ *
+ * @retval true @a the_chain is @c NULL.
+ * @retval false @a the_chain is not @c NULL.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Is_null(
+  const Chain_Control *the_chain
+)
+{
+  return (the_chain == NULL);
+}
+
+/**
+ * @brief Is the chain node pointer NULL.
+ *
+ * This function returns true if the_node is NULL and false otherwise.
+ *
+ * @param[in] the_node is the node pointer to check.
+ *
+ * @retval true @a the_node is @c NULL.
+ * @retval false @a the_node is not @c NULL.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Is_null_node(
+  const Chain_Node *the_node
+)
+{
+  return (the_node == NULL);
+}
+
+/**
+ * @brief Return pointer to chain head.
+ *
+ * This function returns a pointer to the head node on the chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This method returns the permanent head node of the chain.
+ */
+RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Head(
+  Chain_Control *the_chain
+)
+{
+  return &the_chain->Head.Node;
+}
+
+/**
+ * @brief Return pointer to immutable chain head.
+ *
+ * This function returns a pointer to the head node on the chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This method returns the permanent head node of the chain.
+ */
+RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_head(
+  const Chain_Control *the_chain
+)
+{
+  return &the_chain->Head.Node;
+}
+
+/**
+ * @brief Return pointer to chain tail.
+ *
+ * This function returns a pointer to the tail node on the chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This method returns the permanent tail node of the chain.
+ */
+RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Tail(
+  Chain_Control *the_chain
+)
+{
+  return &the_chain->Tail.Node;
+}
+
+/**
+ * @brief Return pointer to immutable chain tail.
+ *
+ * This function returns a pointer to the tail node on the chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This method returns the permanent tail node of the chain.
+ */
+RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_tail(
+  const Chain_Control *the_chain
+)
+{
+  return &the_chain->Tail.Node;
+}
+
+/**
+ * @brief Return pointer to chain's first node.
+ *
+ * This function returns a pointer to the first node on the chain after the
+ * head.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This method returns the first node of the chain.
+ */
+RTEMS_INLINE_ROUTINE Chain_Node *_Chain_First(
+  Chain_Control *the_chain
+)
+{
+  return _Chain_Head( the_chain )->next;
+}
+
+/**
+ * @brief Return pointer to immutable chain's first node.
+ *
+ * This function returns a pointer to the first node on the chain after the
+ * head.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This method returns the first node of the chain.
+ */
+RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_first(
+  const Chain_Control *the_chain
+)
+{
+  return _Chain_Immutable_head( the_chain )->next;
+}
+
+/**
+ * @brief Return pointer to chain's last node.
+ *
+ * This function returns a pointer to the last node on the chain just before
+ * the tail.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This method returns the last node of the chain.
+ */
+RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Last(
+  Chain_Control *the_chain
+)
+{
+  return _Chain_Tail( the_chain )->previous;
+}
+
+/**
+ * @brief Return pointer to immutable chain's last node.
+ *
+ * This function returns a pointer to the last node on the chain just before
+ * the tail.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This method returns the last node of the chain.
+ */
+RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_last(
+  const Chain_Control *the_chain
+)
+{
+  return _Chain_Immutable_tail( the_chain )->previous;
+}
+
+/**
+ * @brief Return pointer the next node from this node.
+ *
+ * This function returns a pointer to the next node after this node.
+ *
+ * @param[in] the_node is the node to be operated upon.
+ *
+ * @return This method returns the next node on the chain.
+ */
+RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Next(
+  Chain_Node *the_node
+)
+{
+  return the_node->next;
+}
+
+/**
+ * @brief Return pointer the immutable next node from this node.
+ *
+ * This function returns a pointer to the next node after this node.
+ *
+ * @param[in] the_node is the node to be operated upon.
+ *
+ * @return This method returns the next node on the chain.
+ */
+RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_next(
+  const Chain_Node *the_node
+)
+{
+  return the_node->next;
+}
+
+/**
+ * @brief Return pointer the previous node from this node.
+ *
+ * This function returns a pointer to the previous node on this chain.
+ *
+ * @param[in] the_node is the node to be operated upon.
+ *
+ * @return This method returns the previous node on the chain.
+ */
+RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Previous(
+  Chain_Node *the_node
+)
+{
+  return the_node->previous;
+}
+
+/**
+ * @brief Return pointer the immutable previous node from this node.
+ *
+ * This function returns a pointer to the previous node on this chain.
+ *
+ * @param[in] the_node is the node to be operated upon.
+ *
+ * @return This method returns the previous node on the chain.
+ */
+RTEMS_INLINE_ROUTINE const Chain_Node *_Chain_Immutable_previous(
+  const Chain_Node *the_node
+)
+{
+  return the_node->previous;
+}
+
+/**
+ * @brief Is the chain empty.
+ *
+ * This function returns true if there a no nodes on @a the_chain and
+ * false otherwise.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @retval true There are no nodes on @a the_chain.
+ * @retval false There are nodes on @a the_chain.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Is_empty(
+  const Chain_Control *the_chain
+)
+{
+  return _Chain_Immutable_first( the_chain )
+    == _Chain_Immutable_tail( the_chain );
+}
+
+/**
+ * @brief Is this the first node on the chain.
+ *
+ * This function returns true if the_node is the first node on a chain and
+ * false otherwise.
+ *
+ * @param[in] the_node is the node the caller wants to know if it is
+ *            the first node on a chain.
+ *
+ * @retval true @a the_node is the first node on a chain.
+ * @retval false @a the_node is not the first node on a chain.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Is_first(
+  const Chain_Node *the_node
+)
+{
+  return (the_node->previous->previous == NULL);
+}
+
+/**
+ * @brief Is this the last node on the chain.
+ *
+ * This function returns true if @a the_node is the last node on a chain and
+ * false otherwise.
+ *
+ * @param[in] the_node is the node to check as the last node.
+ *
+ * @retval true @a the_node is the last node on a chain.
+ * @retval false @a the_node is not the last node on a chain.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Is_last(
+  const Chain_Node *the_node
+)
+{
+  return (the_node->next->next == NULL);
+}
+
+/**
+ * @brief Does this chain have only one node.
+ *
+ * This function returns true if there is only one node on @a the_chain and
+ * false otherwise.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ *
+ * @return This function returns true if there is only one node on
+ *         @a the_chain and false otherwise.
+ *
+ * @retval true There is only one node on @a the_chain.
+ * @retval false There is more than one node on @a the_chain.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Has_only_one_node(
+  const Chain_Control *the_chain
+)
+{
+  return _Chain_Immutable_first( the_chain )
+    == _Chain_Immutable_last( the_chain );
+}
+
+/**
+ * @brief Is this node the chain head.
+ *
+ * This function returns true if @a the_node is the head of @a the_chain and
+ * false otherwise.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to check for being the Chain Head.
+ *
+ * @retval true @a the_node is the head of @a the_chain.
+ * @retval false @a the_node is not the head of @a the_chain.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Is_head(
+  const Chain_Control *the_chain,
+  const Chain_Node    *the_node
+)
+{
+  return (the_node == _Chain_Immutable_head( the_chain ));
+}
+
+/**
+ * @brief Is this node the chail tail.
+ *
+ * This function returns true if @a the_node is the tail of @a the_chain and
+ * false otherwise.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to check for being the Chain Tail.
+ *
+ * @retval true @a the_node is the tail of @a the_chain.
+ * @retval false @a the_node is not the tail of @a the_chain.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Is_tail(
+  const Chain_Control *the_chain,
+  const Chain_Node    *the_node
+)
+{
+  return (the_node == _Chain_Immutable_tail( the_chain ));
+}
+
+/**
+ * @brief Initialize this chain as empty.
+ *
+ * This routine initializes the specified chain to contain zero nodes.
+ *
+ * @param[in] the_chain is the chain to be initialized.
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Initialize_empty(
+  Chain_Control *the_chain
+)
+{
+  Chain_Node *head = _Chain_Head( the_chain );
+  Chain_Node *tail = _Chain_Tail( the_chain );
+
+  head->next = tail;
+  head->previous = NULL;
+  tail->previous = head;
+}
+
+/**
+ * @brief Extract this node (unprotected).
+ *
+ * This routine extracts the_node from the chain on which it resides.
+ * It does NOT disable interrupts to ensure the atomicity of the
+ * extract operation.
+ *
+ * @param[in] the_node is the node to be extracted.
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Extract_unprotected(
+  Chain_Node *the_node
+)
+{
+  Chain_Node *next;
+  Chain_Node *previous;
+
+  next           = the_node->next;
+  previous       = the_node->previous;
+  next->previous = previous;
+  previous->next = next;
+}
+
+/**
+ * @brief Get the first node (unprotected).
+ *
+ * This function removes the first node from the_chain and returns
+ * a pointer to that node.  It does NOT disable interrupts to ensure
+ * the atomicity of the get operation.
+ *
+ * @param[in] the_chain is the chain to attempt to get the first node from.
+ *
+ * @return This method returns the first node on the chain even if it is
+ *         the Chain Tail.
+ *
+ * @note This routine assumes that there is at least one node on the chain
+ *       and always returns a node even if it is the Chain Tail.
+ */
+RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Get_first_unprotected(
+  Chain_Control *the_chain
+)
+{
+  Chain_Node *head = _Chain_Head( the_chain );
+  Chain_Node *old_first = head->next;
+  Chain_Node *new_first = old_first->next;
+
+  head->next = new_first;
+  new_first->previous = head;
+
+  return old_first;
+}
+
+/**
+ * @brief Get the first node (unprotected).
+ *
+ * This function removes the first node from the_chain and returns
+ * a pointer to that node.  If the_chain is empty, then NULL is returned.
+ *
+ * @param[in] the_chain is the chain to attempt to get the first node from.
+ *
+ * @return This method returns the first node on the chain or NULL if the
+ *         chain is empty.
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity of the
+ *       get operation.
+ */
+RTEMS_INLINE_ROUTINE Chain_Node *_Chain_Get_unprotected(
+  Chain_Control *the_chain
+)
+{
+  if ( !_Chain_Is_empty(the_chain))
+    return _Chain_Get_first_unprotected(the_chain);
+  else
+    return NULL;
+}
+
+/**
+ * @brief Insert a node (unprotected).
+ *
+ * This routine inserts the_node on a chain immediately following
+ * after_node.
+ *
+ * @param[in] after_node is the node which will precede @a the_node on the
+ *            chain.
+ * @param[in] the_node is the node to be inserted.
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity
+ *       of the extract operation.
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Insert_unprotected(
+  Chain_Node *after_node,
+  Chain_Node *the_node
+)
+{
+  Chain_Node *before_node;
+
+  the_node->previous    = after_node;
+  before_node           = after_node->next;
+  after_node->next      = the_node;
+  the_node->next        = before_node;
+  before_node->previous = the_node;
+}
+
+/**
+ * @brief Append a node (unprotected).
+ *
+ * This routine appends the_node onto the end of the_chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to be appended.
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity of the
+ *       append operation.
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Append_unprotected(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+)
+{
+  Chain_Node *tail = _Chain_Tail( the_chain );
+  Chain_Node *old_last = tail->previous;
+
+  the_node->next = tail;
+  tail->previous = the_node;
+  old_last->next = the_node;
+  the_node->previous = old_last;
+}
+
+/**
+ * @brief Append a node on the end of a chain if the node is in the off chain
+ * state (unprotected).
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity of the
+ *       append operation.
+ *
+ * @see _Chain_Append_unprotected() and _Chain_Is_node_off_chain().
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Append_if_is_off_chain_unprotected(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+)
+{
+  if ( _Chain_Is_node_off_chain( the_node ) ) {
+    _Chain_Append_unprotected( the_chain, the_node );
+  }
+}
+
+/**
+ * @brief Prepend a node (unprotected).
+ *
+ * This routine prepends the_node onto the front of the_chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to be prepended.
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity of the
+ *       prepend operation.
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Prepend_unprotected(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+)
+{
+  _Chain_Insert_unprotected(_Chain_Head(the_chain), the_node);
+}
+
+/**
+ * @brief Prepend a node (protected).
+ *
+ * This routine prepends the_node onto the front of the_chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to be prepended.
+ *
+ * @note It disables interrupts to ensure the atomicity of the
+ *       prepend operation.
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Prepend(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+)
+{
+  _Chain_Insert(_Chain_Head(the_chain), the_node);
+}
+
+/**
+ * @brief Append a node and check if the chain was empty before (unprotected).
+ *
+ * This routine appends the_node onto the end of the_chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to be appended.
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity of the
+ *       append operation.
+ *
+ * @retval true The chain was empty before.
+ * @retval false The chain contained at least one node before.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Append_with_empty_check_unprotected(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+)
+{
+  bool was_empty = _Chain_Is_empty( the_chain );
+
+  _Chain_Append_unprotected( the_chain, the_node );
+
+  return was_empty;
+}
+
+/**
+ * @brief Prepend a node and check if the chain was empty before (unprotected).
+ *
+ * This routine prepends the_node onto the front of the_chain.
+ *
+ * @param[in] the_chain is the chain to be operated upon.
+ * @param[in] the_node is the node to be prepended.
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity of the
+ *       prepend operation.
+ *
+ * @retval true The chain was empty before.
+ * @retval false The chain contained at least one node before.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Prepend_with_empty_check_unprotected(
+  Chain_Control *the_chain,
+  Chain_Node    *the_node
+)
+{
+  bool was_empty = _Chain_Is_empty( the_chain );
+
+  _Chain_Prepend_unprotected( the_chain, the_node );
+
+  return was_empty;
+}
+
+/**
+ * @brief Get the first node and check if the chain is empty afterwards
+ * (unprotected).
+ *
+ * This function removes the first node from the_chain and returns
+ * a pointer to that node in @a the_node.  If the_chain is empty, then NULL is
+ * returned.
+ *
+ * @param[in] the_chain is the chain to attempt to get the first node from.
+ * @param[out] the_node is the first node on the chain or NULL if the chain is
+ * empty.
+ *
+ * @note It does NOT disable interrupts to ensure the atomicity of the
+ *       get operation.
+ *
+ * @retval true The chain is empty now.
+ * @retval false The chain contains at least one node now.
+ */
+RTEMS_INLINE_ROUTINE bool _Chain_Get_with_empty_check_unprotected(
+  Chain_Control *the_chain,
+  Chain_Node **the_node
+)
+{
+  bool is_empty_now = true;
+  Chain_Node *head = _Chain_Head( the_chain );
+  Chain_Node *tail = _Chain_Tail( the_chain );
+  Chain_Node *old_first = head->next;
+
+  if ( old_first != tail ) {
+    Chain_Node *new_first = old_first->next;
+
+    head->next = new_first;
+    new_first->previous = head;
+
+    *the_node = old_first;
+
+    is_empty_now = new_first == tail;
+  } else
+    *the_node = NULL;
+
+  return is_empty_now;
+}
+
+/**
+ * @brief Chain node order.
+ *
+ * @param[in] left The left node.
+ * @param[in] right The right node.
+ *
+ * @retval true According to the order the left node precedes the right node.
+ * @retval false Otherwise.
+ */
+typedef bool ( *Chain_Node_order )(
+  const Chain_Node *left,
+  const Chain_Node *right
+);
+
+/**
+ * @brief Inserts a node into the chain according to the order relation.
+ *
+ * After the operation the chain contains the node to insert and the order
+ * relation holds for all nodes from the head up to the inserted node.  Nodes
+ * after the inserted node are not moved.
+ *
+ * @param[in,out] chain The chain.
+ * @param[in,out] to_insert The node to insert.
+ * @param[in] order The order relation.
+ */
+RTEMS_INLINE_ROUTINE void _Chain_Insert_ordered_unprotected(
+  Chain_Control *chain,
+  Chain_Node *to_insert,
+  Chain_Node_order order
+)
+{
+  const Chain_Node *tail = _Chain_Immutable_tail( chain );
+  Chain_Node *next = _Chain_First( chain );
+
+  while ( next != tail && !( *order )( to_insert, next ) ) {
+    next = _Chain_Next( next );
+  }
+
+  _Chain_Insert_unprotected( _Chain_Previous( next ), to_insert );
+}
+
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
+/* end of include file */
diff --git a/cpukit/score/include/rtems/score/coremsgimpl.h b/cpukit/score/include/rtems/score/coremsgimpl.h
index f579e6363b..d9f8f91c0b 100644
--- a/cpukit/score/include/rtems/score/coremsgimpl.h
+++ b/cpukit/score/include/rtems/score/coremsgimpl.h
@@ -20,6 +20,7 @@
 #define _RTEMS_SCORE_COREMSGIMPL_H
 
 #include <rtems/score/coremsg.h>
+#include <rtems/score/chainimpl.h>
 
 #include <limits.h>
 #include <string.h>
diff --git a/cpukit/score/include/rtems/score/coremuteximpl.h b/cpukit/score/include/rtems/score/coremuteximpl.h
index e84875d963..5a139556ca 100644
--- a/cpukit/score/include/rtems/score/coremuteximpl.h
+++ b/cpukit/score/include/rtems/score/coremuteximpl.h
@@ -19,6 +19,7 @@
 #define _RTEMS_SCORE_COREMUTEXIMPL_H
 
 #include <rtems/score/coremutex.h>
+#include <rtems/score/chainimpl.h>
 #include <rtems/score/threaddispatch.h>
 
 #ifdef __cplusplus
diff --git a/cpukit/score/include/rtems/score/userextimpl.h b/cpukit/score/include/rtems/score/userextimpl.h
index 6ecdcc579a..a79b858b26 100644
--- a/cpukit/score/include/rtems/score/userextimpl.h
+++ b/cpukit/score/include/rtems/score/userextimpl.h
@@ -19,6 +19,7 @@
 #define _RTEMS_SCORE_USEREXTIMPL_H
 
 #include <rtems/score/userext.h>
+#include <rtems/score/chainimpl.h>
 
 #ifdef __cplusplus
 extern "C" {