[mirror_edk2.git] / MdePkg / Library / BaseSynchronizationLib / Synchronization.c

/** @file\r
  Implementation of synchronization functions.\r
\r
  Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php.\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "BaseSynchronizationLibInternals.h"\r
\r
#define SPIN_LOCK_RELEASED          ((UINTN) 1)\r
#define SPIN_LOCK_ACQUIRED          ((UINTN) 2)\r
\r
/**\r
  Retrieves the architecture specific spin lock alignment requirements for\r
  optimal spin lock performance.\r
\r
  This function retrieves the spin lock alignment requirements for optimal\r
  performance on a given CPU architecture. The spin lock alignment must be a\r
  power of two and is returned by this function. If there are no alignment\r
  requirements, then 1 must be returned. The spin lock synchronization\r
  functions must function correctly if the spin lock size and alignment values\r
  returned by this function are not used at all. These values are hints to the\r
  consumers of the spin lock synchronization functions to obtain optimal spin\r
  lock performance.\r
\r
  @return The architecture specific spin lock alignment.\r
\r
**/\r
UINTN\r
EFIAPI\r
GetSpinLockProperties (\r
  VOID\r
  )\r
{\r
  return 32;\r
}\r
\r
/**\r
  Initializes a spin lock to the released state and returns the spin lock.\r
\r
  This function initializes the spin lock specified by SpinLock to the released\r
  state, and returns SpinLock. Optimal performance can be achieved by calling\r
  GetSpinLockProperties() to determine the size and alignment requirements for\r
  SpinLock.\r
\r
  If SpinLock is NULL, then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to initialize to the released\r
                    state.\r
\r
  @return SpinLock is in release state.\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
InitializeSpinLock (\r
  OUT      SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  ASSERT (SpinLock != NULL);\r
  *SpinLock = SPIN_LOCK_RELEASED;\r
  return SpinLock;\r
}\r
\r
/**\r
  Waits until a spin lock can be placed in the acquired state.\r
\r
  This function checks the state of the spin lock specified by SpinLock. If\r
  SpinLock is in the released state, then this function places SpinLock in the\r
  acquired state and returns SpinLock. Otherwise, this function waits\r
  indefinitely for the spin lock to be released, and then places it in the\r
  acquired state and returns SpinLock. All state transitions of SpinLock must\r
  be performed using MP safe mechanisms.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
  If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
  PcdSpinLockTimeout microseconds, then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
\r
  @return SpinLock acquired the lock.\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
AcquireSpinLock (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  UINT64  Current;\r
  UINT64  Previous;\r
  UINT64  Total;\r
  UINT64  Start;\r
  UINT64  End;\r
  UINT64  Timeout;\r
  INT64   Cycle;\r
  INT64   Delta;\r
\r
  if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
    //\r
    // Get the current timer value\r
    //\r
    Current = GetPerformanceCounter();\r
\r
    //\r
    // Initialize local variables\r
    //\r
    Start = 0;\r
    End   = 0;\r
    Total = 0;\r
\r
    //\r
    // Retrieve the performance counter properties and compute the number of performance\r
    // counter ticks required to reach the timeout\r
    //\r
    Timeout = DivU64x32 (\r
                MultU64x32 (\r
                  GetPerformanceCounterProperties (&Start, &End),\r
                  PcdGet32 (PcdSpinLockTimeout)\r
                  ),\r
                1000000\r
                );\r
    Cycle = End - Start;\r
    if (Cycle < 0) {\r
      Cycle = -Cycle;\r
    }\r
    Cycle++;\r
\r
    while (!AcquireSpinLockOrFail (SpinLock)) {\r
      CpuPause ();\r
      Previous = Current;\r
      Current  = GetPerformanceCounter();\r
      Delta = (INT64) (Current - Previous);\r
      if (Start > End) {\r
        Delta = -Delta;\r
      }\r
      if (Delta < 0) {\r
        Delta += Cycle;\r
      }\r
      Total += Delta;\r
      ASSERT (Total < Timeout);\r
    }\r
  } else {\r
    while (!AcquireSpinLockOrFail (SpinLock)) {\r
      CpuPause ();\r
    }\r
  }\r
  return SpinLock;\r
}\r
\r
/**\r
  Attempts to place a spin lock in the acquired state.\r
\r
  This function checks the state of the spin lock specified by SpinLock. If\r
  SpinLock is in the released state, then this function places SpinLock in the\r
  acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
  transitions of SpinLock must be performed using MP safe mechanisms.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
\r
  @retval TRUE  SpinLock was placed in the acquired state.\r
  @retval FALSE SpinLock could not be acquired.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
AcquireSpinLockOrFail (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  SPIN_LOCK    LockValue;\r
\r
  ASSERT (SpinLock != NULL);\r
\r
  LockValue = *SpinLock;\r
  ASSERT (SPIN_LOCK_ACQUIRED == LockValue || SPIN_LOCK_RELEASED == LockValue);\r
\r
  return (BOOLEAN)(\r
           InterlockedCompareExchangePointer (\r
             (VOID**)SpinLock,\r
             (VOID*)SPIN_LOCK_RELEASED,\r
             (VOID*)SPIN_LOCK_ACQUIRED\r
             ) == (VOID*)SPIN_LOCK_RELEASED\r
           );\r
}\r
\r
/**\r
  Releases a spin lock.\r
\r
  This function places the spin lock specified by SpinLock in the release state\r
  and returns SpinLock.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to release.\r
\r
  @return SpinLock released lock.\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
ReleaseSpinLock (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  SPIN_LOCK    LockValue;\r
\r
  ASSERT (SpinLock != NULL);\r
\r
  LockValue = *SpinLock;\r
  ASSERT (SPIN_LOCK_ACQUIRED == LockValue || SPIN_LOCK_RELEASED == LockValue);\r
\r
  *SpinLock = SPIN_LOCK_RELEASED;\r
  return SpinLock;\r
}\r
\r
/**\r
  Performs an atomic increment of an 32-bit unsigned integer.\r
\r
  Performs an atomic increment of the 32-bit unsigned integer specified by\r
  Value and returns the incremented value. The increment operation must be\r
  performed using MP safe mechanisms. The state of the return value is not\r
  guaranteed to be MP safe.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value A pointer to the 32-bit value to increment.\r
\r
  @return The incremented value.\r
\r
**/\r
UINT32\r
EFIAPI\r
InterlockedIncrement (\r
  IN      UINT32                    *Value\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncIncrement (Value);\r
}\r
\r
/**\r
  Performs an atomic decrement of an 32-bit unsigned integer.\r
\r
  Performs an atomic decrement of the 32-bit unsigned integer specified by\r
  Value and returns the decremented value. The decrement operation must be\r
  performed using MP safe mechanisms. The state of the return value is not\r
  guaranteed to be MP safe.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value A pointer to the 32-bit value to decrement.\r
\r
  @return The decremented value.\r
\r
**/\r
UINT32\r
EFIAPI\r
InterlockedDecrement (\r
  IN      UINT32                    *Value\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncDecrement (Value);\r
}\r
\r
/**\r
  Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
\r
  Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
  specified by Value.  If Value is equal to CompareValue, then Value is set to\r
  ExchangeValue and CompareValue is returned.  If Value is not equal to CompareValue,\r
  then Value is returned.  The compare exchange operation must be performed using\r
  MP safe mechanisms.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value         A pointer to the 32-bit value for the compare exchange\r
                        operation.\r
  @param  CompareValue  32-bit value used in compare operation.\r
  @param  ExchangeValue 32-bit value used in exchange operation.\r
\r
  @return The original *Value before exchange.\r
\r
**/\r
UINT32\r
EFIAPI\r
InterlockedCompareExchange32 (\r
  IN OUT  UINT32                    *Value,\r
  IN      UINT32                    CompareValue,\r
  IN      UINT32                    ExchangeValue\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
}\r
\r
/**\r
  Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
\r
  Performs an atomic compare exchange operation on the 64-bit unsigned integer specified\r
  by Value.  If Value is equal to CompareValue, then Value is set to ExchangeValue and\r
  CompareValue is returned.  If Value is not equal to CompareValue, then Value is returned.\r
  The compare exchange operation must be performed using MP safe mechanisms.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value         A pointer to the 64-bit value for the compare exchange\r
                        operation.\r
  @param  CompareValue  64-bit value used in compare operation.\r
  @param  ExchangeValue 64-bit value used in exchange operation.\r
\r
  @return The original *Value before exchange.\r
\r
**/\r
UINT64\r
EFIAPI\r
InterlockedCompareExchange64 (\r
  IN OUT  UINT64                    *Value,\r
  IN      UINT64                    CompareValue,\r
  IN      UINT64                    ExchangeValue\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
}\r
\r
/**\r
  Performs an atomic compare exchange operation on a pointer value.\r
\r
  Performs an atomic compare exchange operation on the pointer value specified\r
  by Value. If Value is equal to CompareValue, then Value is set to\r
  ExchangeValue and CompareValue is returned. If Value is not equal to\r
  CompareValue, then Value is returned. The compare exchange operation must be\r
  performed using MP safe mechanisms.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value         A pointer to the pointer value for the compare exchange\r
                        operation.\r
  @param  CompareValue  Pointer value used in compare operation.\r
  @param  ExchangeValue Pointer value used in exchange operation.\r
\r
  @return The original *Value before exchange.\r
**/\r
VOID *\r
EFIAPI\r
InterlockedCompareExchangePointer (\r
  IN OUT  VOID                      **Value,\r
  IN      VOID                      *CompareValue,\r
  IN      VOID                      *ExchangeValue\r
  )\r
{\r
  UINT8  SizeOfValue;\r
\r
  SizeOfValue = sizeof (*Value);\r
\r
  switch (SizeOfValue) {\r
    case sizeof (UINT32):\r
      return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
                             (UINT32*)Value,\r
                             (UINT32)(UINTN)CompareValue,\r
                             (UINT32)(UINTN)ExchangeValue\r
                             );\r
    case sizeof (UINT64):\r
      return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
                             (UINT64*)Value,\r
                             (UINT64)(UINTN)CompareValue,\r
                             (UINT64)(UINTN)ExchangeValue\r
                             );\r
    default:\r
      ASSERT (FALSE);\r
      return NULL;\r
  }\r
}\r
Commit	Line	Data
720d3c5f	1	/** @file\r
	2	Implementation of synchronization functions.\r
	3	\r
2fc59a00	4	Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>\r
e2d9bfb2	5	This program and the accompanying materials\r
720d3c5f	6	are licensed and made available under the terms and conditions of the BSD License\r
720d3c5f	7	which accompanies this distribution. The full text of the license may be found at\r
2fc59a00	8	http://opensource.org/licenses/bsd-license.php.\r
720d3c5f	9	\r
	10	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	11	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	12	\r
	13	**/\r
	14	\r
	15	#include "BaseSynchronizationLibInternals.h"\r
	16	\r
	17	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
	18	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
	19	\r
	20	/**\r
	21	Retrieves the architecture specific spin lock alignment requirements for\r
	22	optimal spin lock performance.\r
	23	\r
	24	This function retrieves the spin lock alignment requirements for optimal\r
	25	performance on a given CPU architecture. The spin lock alignment must be a\r
	26	power of two and is returned by this function. If there are no alignment\r
	27	requirements, then 1 must be returned. The spin lock synchronization\r
	28	functions must function correctly if the spin lock size and alignment values\r
	29	returned by this function are not used at all. These values are hints to the\r
	30	consumers of the spin lock synchronization functions to obtain optimal spin\r
	31	lock performance.\r
	32	\r
	33	@return The architecture specific spin lock alignment.\r
	34	\r
	35	**/\r
	36	UINTN\r
	37	EFIAPI\r
	38	GetSpinLockProperties (\r
	39	VOID\r
	40	)\r
	41	{\r
	42	return 32;\r
	43	}\r
	44	\r
	45	/**\r
	46	Initializes a spin lock to the released state and returns the spin lock.\r
	47	\r
	48	This function initializes the spin lock specified by SpinLock to the released\r
	49	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	50	GetSpinLockProperties() to determine the size and alignment requirements for\r
	51	SpinLock.\r
	52	\r
	53	If SpinLock is NULL, then ASSERT().\r
	54	\r
	55	@param SpinLock A pointer to the spin lock to initialize to the released\r
	56	state.\r
	57	\r
2fc59a00	58	@return SpinLock is in release state.\r
720d3c5f	59	\r
	60	**/\r
	61	SPIN_LOCK *\r
	62	EFIAPI\r
	63	InitializeSpinLock (\r
	64	OUT SPIN_LOCK *SpinLock\r
	65	)\r
	66	{\r
	67	ASSERT (SpinLock != NULL);\r
	68	*SpinLock = SPIN_LOCK_RELEASED;\r
	69	return SpinLock;\r
	70	}\r
	71	\r
	72	/**\r
	73	Waits until a spin lock can be placed in the acquired state.\r
	74	\r
	75	This function checks the state of the spin lock specified by SpinLock. If\r
	76	SpinLock is in the released state, then this function places SpinLock in the\r
	77	acquired state and returns SpinLock. Otherwise, this function waits\r
	78	indefinitely for the spin lock to be released, and then places it in the\r
	79	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	80	be performed using MP safe mechanisms.\r
	81	\r
	82	If SpinLock is NULL, then ASSERT().\r
	83	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	84	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	85	PcdSpinLockTimeout microseconds, then ASSERT().\r
	86	\r
	87	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	88	\r
2fc59a00	89	@return SpinLock acquired the lock.\r
720d3c5f	90	\r
	91	**/\r
	92	SPIN_LOCK *\r
	93	EFIAPI\r
	94	AcquireSpinLock (\r
	95	IN OUT SPIN_LOCK *SpinLock\r
	96	)\r
	97	{\r
	98	UINT64 Current;\r
	99	UINT64 Previous;\r
	100	UINT64 Total;\r
	101	UINT64 Start;\r
	102	UINT64 End;\r
	103	UINT64 Timeout;\r
	104	INT64 Cycle;\r
	105	INT64 Delta;\r
	106	\r
	107	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
	108	//\r
	109	// Get the current timer value\r
	110	//\r
	111	Current = GetPerformanceCounter();\r
	112	\r
	113	//\r
	114	// Initialize local variables\r
	115	//\r
	116	Start = 0;\r
	117	End = 0;\r
	118	Total = 0;\r
	119	\r
	120	//\r
	121	// Retrieve the performance counter properties and compute the number of performance\r
	122	// counter ticks required to reach the timeout\r
	123	//\r
	124	Timeout = DivU64x32 (\r
	125	MultU64x32 (\r
	126	GetPerformanceCounterProperties (&Start, &End),\r
	127	PcdGet32 (PcdSpinLockTimeout)\r
	128	),\r
	129	1000000\r
	130	);\r
	131	Cycle = End - Start;\r
	132	if (Cycle < 0) {\r
	133	Cycle = -Cycle;\r
	134	}\r
	135	Cycle++;\r
	136	\r
	137	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	138	CpuPause ();\r
	139	Previous = Current;\r
	140	Current = GetPerformanceCounter();\r
	141	Delta = (INT64) (Current - Previous);\r
	142	if (Start > End) {\r
	143	Delta = -Delta;\r
	144	}\r
	145	if (Delta < 0) {\r
	146	Delta += Cycle;\r
	147	}\r
	148	Total += Delta;\r
	149	ASSERT (Total < Timeout);\r
	150	}\r
	151	} else {\r
	152	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	153	CpuPause ();\r
154	}\r
155	}\r
156	return SpinLock;\r
157	}\r
158	\r
159	/**\r
160	Attempts to place a spin lock in the acquired state.\r
161	\r
162	This function checks the state of the spin lock specified by SpinLock. If\r
163	SpinLock is in the released state, then this function places SpinLock in the\r
164	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
165	transitions of SpinLock must be performed using MP safe mechanisms.\r
166	\r
167	If SpinLock is NULL, then ASSERT().\r
168	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
169	\r
170	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
171	\r
172	@retval TRUE SpinLock was placed in the acquired state.\r
173	@retval FALSE SpinLock could not be acquired.\r
174	\r
175	**/\r
176	BOOLEAN\r
177	EFIAPI\r
178	AcquireSpinLockOrFail (\r
179	IN OUT SPIN_LOCK *SpinLock\r
180	)\r
181	{\r
182	SPIN_LOCK LockValue;\r
183	\r
184	ASSERT (SpinLock != NULL);\r
185	\r
186	LockValue = *SpinLock;\r
187	ASSERT (SPIN_LOCK_ACQUIRED == LockValue \|\| SPIN_LOCK_RELEASED == LockValue);\r
188	\r
189	return (BOOLEAN)(\r
190	InterlockedCompareExchangePointer (\r
191	(VOID**)SpinLock,\r
192	(VOID*)SPIN_LOCK_RELEASED,\r
193	(VOID*)SPIN_LOCK_ACQUIRED\r
194	) == (VOID*)SPIN_LOCK_RELEASED\r
195	);\r
196	}\r
197	\r
198	/**\r
199	Releases a spin lock.\r
200	\r
201	This function places the spin lock specified by SpinLock in the release state\r
202	and returns SpinLock.\r
203	\r
204	If SpinLock is NULL, then ASSERT().\r
205	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
206	\r
207	@param SpinLock A pointer to the spin lock to release.\r
208	\r
209	@return SpinLock released lock.\r
210	\r
211	**/\r
212	SPIN_LOCK *\r
213	EFIAPI\r
214	ReleaseSpinLock (\r
215	IN OUT SPIN_LOCK *SpinLock\r
216	)\r
217	{\r
218	SPIN_LOCK LockValue;\r
219	\r
220	ASSERT (SpinLock != NULL);\r
221	\r
222	LockValue = *SpinLock;\r
223	ASSERT (SPIN_LOCK_ACQUIRED == LockValue \|\| SPIN_LOCK_RELEASED == LockValue);\r
224	\r
225	*SpinLock = SPIN_LOCK_RELEASED;\r
226	return SpinLock;\r
227	}\r
228	\r
229	/**\r
230	Performs an atomic increment of an 32-bit unsigned integer.\r
231	\r
232	Performs an atomic increment of the 32-bit unsigned integer specified by\r
233	Value and returns the incremented value. The increment operation must be\r
234	performed using MP safe mechanisms. The state of the return value is not\r
235	guaranteed to be MP safe.\r
236	\r
237	If Value is NULL, then ASSERT().\r
238	\r
239	@param Value A pointer to the 32-bit value to increment.\r
240	\r
241	@return The incremented value.\r
242	\r
243	**/\r
244	UINT32\r
245	EFIAPI\r
246	InterlockedIncrement (\r
247	IN UINT32 *Value\r
248	)\r
249	{\r
250	ASSERT (Value != NULL);\r
251	return InternalSyncIncrement (Value);\r
252	}\r
253	\r
254	/**\r
255	Performs an atomic decrement of an 32-bit unsigned integer.\r
256	\r
257	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
258	Value and returns the decremented value. The decrement operation must be\r
259	performed using MP safe mechanisms. The state of the return value is not\r
260	guaranteed to be MP safe.\r
261	\r
262	If Value is NULL, then ASSERT().\r
263	\r
264	@param Value A pointer to the 32-bit value to decrement.\r
265	\r
266	@return The decremented value.\r
267	\r
268	**/\r
269	UINT32\r
270	EFIAPI\r
271	InterlockedDecrement (\r
272	IN UINT32 *Value\r
273	)\r
274	{\r
275	ASSERT (Value != NULL);\r
276	return InternalSyncDecrement (Value);\r
277	}\r
278	\r
279	/**\r
280	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
281	\r
282	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
283	specified by Value. If Value is equal to CompareValue, then Value is set to\r
284	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
285	then Value is returned. The compare exchange operation must be performed using\r
286	MP safe mechanisms.\r
287	\r
288	If Value is NULL, then ASSERT().\r
289	\r
290	@param Value A pointer to the 32-bit value for the compare exchange\r
291	operation.\r
292	@param CompareValue 32-bit value used in compare operation.\r
293	@param ExchangeValue 32-bit value used in exchange operation.\r
294	\r
295	@return The original *Value before exchange.\r
296	\r
297	**/\r
298	UINT32\r
299	EFIAPI\r
300	InterlockedCompareExchange32 (\r
301	IN OUT UINT32 *Value,\r
302	IN UINT32 CompareValue,\r
303	IN UINT32 ExchangeValue\r
304	)\r
305	{\r
306	ASSERT (Value != NULL);\r
307	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
308	}\r
309	\r
310	/**\r
311	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
312	\r
313	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified\r
314	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and\r
315	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.\r
316	The compare exchange operation must be performed using MP safe mechanisms.\r
317	\r
318	If Value is NULL, then ASSERT().\r
319	\r
320	@param Value A pointer to the 64-bit value for the compare exchange\r
321	operation.\r
322	@param CompareValue 64-bit value used in compare operation.\r
323	@param ExchangeValue 64-bit value used in exchange operation.\r
324	\r
325	@return The original *Value before exchange.\r
326	\r
327	**/\r
328	UINT64\r
329	EFIAPI\r
330	InterlockedCompareExchange64 (\r
331	IN OUT UINT64 *Value,\r
332	IN UINT64 CompareValue,\r
333	IN UINT64 ExchangeValue\r
334	)\r
335	{\r
336	ASSERT (Value != NULL);\r
337	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
338	}\r
339	\r
340	/**\r
341	Performs an atomic compare exchange operation on a pointer value.\r
342	\r
343	Performs an atomic compare exchange operation on the pointer value specified\r
344	by Value. If Value is equal to CompareValue, then Value is set to\r
345	ExchangeValue and CompareValue is returned. If Value is not equal to\r
346	CompareValue, then Value is returned. The compare exchange operation must be\r
347	performed using MP safe mechanisms.\r
348	\r
349	If Value is NULL, then ASSERT().\r
350	\r
351	@param Value A pointer to the pointer value for the compare exchange\r
352	operation.\r
353	@param CompareValue Pointer value used in compare operation.\r
354	@param ExchangeValue Pointer value used in exchange operation.\r
355	\r
356	@return The original *Value before exchange.\r
357	**/\r
358	VOID *\r
359	EFIAPI\r
360	InterlockedCompareExchangePointer (\r
361	IN OUT VOID **Value,\r
362	IN VOID *CompareValue,\r
363	IN VOID *ExchangeValue\r
364	)\r
365	{\r
366	UINT8 SizeOfValue;\r
367	\r
368	SizeOfValue = sizeof (*Value);\r
369	\r
370	switch (SizeOfValue) {\r
371	case sizeof (UINT32):\r
372	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
373	(UINT32*)Value,\r
374	(UINT32)(UINTN)CompareValue,\r
375	(UINT32)(UINTN)ExchangeValue\r
376	);\r
377	case sizeof (UINT64):\r
378	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
379	(UINT64*)Value,\r
380	(UINT64)(UINTN)CompareValue,\r
381	(UINT64)(UINTN)ExchangeValue\r
382	);\r
383	default:\r
384	ASSERT (FALSE);\r
385	return NULL;\r
386	}\r
387	}\r