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

/** @file\r
  Implementation of synchronization functions.\r
\r
  Copyright (c) 2006, Intel Corporation<BR>\r
  All rights reserved. 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
//\r
// Include common header file for this module.\r
//\r
\r
\r
#include "BaseLibInternals.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
  // @bug May use a PCD entry to determine this alignment.\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\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\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 (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\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\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 (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\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
**/\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
e1f414b6	1	/** @file\r
	2	Implementation of synchronization functions.\r
	3	\r
	4	Copyright (c) 2006, Intel Corporation<BR>\r
	5	All rights reserved. This program and the accompanying materials\r
	6	are licensed and made available under the terms and conditions of the BSD License\r
	7	which accompanies this distribution. The full text of the license may be found at\r
	8	http://opensource.org/licenses/bsd-license.php\r
	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
e1f414b6	13	**/\r
	14	\r
	15	//\r
	16	// Include common header file for this module.\r
	17	//\r
f734a10a	18	\r
e1f414b6	19	\r
	20	#include "BaseLibInternals.h"\r
	21	\r
	22	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
	23	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
	24	\r
	25	/**\r
	26	Retrieves the architecture specific spin lock alignment requirements for\r
	27	optimal spin lock performance.\r
	28	\r
	29	This function retrieves the spin lock alignment requirements for optimal\r
	30	performance on a given CPU architecture. The spin lock alignment must be a\r
	31	power of two and is returned by this function. If there are no alignment\r
	32	requirements, then 1 must be returned. The spin lock synchronization\r
	33	functions must function correctly if the spin lock size and alignment values\r
	34	returned by this function are not used at all. These values are hints to the\r
	35	consumers of the spin lock synchronization functions to obtain optimal spin\r
	36	lock performance.\r
	37	\r
	38	@return The architecture specific spin lock alignment.\r
	39	\r
	40	**/\r
	41	UINTN\r
	42	EFIAPI\r
	43	GetSpinLockProperties (\r
	44	VOID\r
	45	)\r
	46	{\r
	47	// @bug May use a PCD entry to determine this alignment.\r
	48	return 32;\r
	49	}\r
	50	\r
	51	/**\r
	52	Initializes a spin lock to the released state and returns the spin lock.\r
	53	\r
	54	This function initializes the spin lock specified by SpinLock to the released\r
	55	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	56	GetSpinLockProperties() to determine the size and alignment requirements for\r
	57	SpinLock.\r
	58	\r
	59	If SpinLock is NULL, then ASSERT().\r
	60	\r
	61	@param SpinLock A pointer to the spin lock to initialize to the released\r
	62	state.\r
	63	\r
	64	@return SpinLock\r
	65	\r
	66	**/\r
	67	SPIN_LOCK *\r
	68	EFIAPI\r
	69	InitializeSpinLock (\r
	70	OUT SPIN_LOCK *SpinLock\r
	71	)\r
	72	{\r
	73	ASSERT (SpinLock != NULL);\r
	74	*SpinLock = SPIN_LOCK_RELEASED;\r
	75	return SpinLock;\r
	76	}\r
	77	\r
	78	/**\r
	79	Waits until a spin lock can be placed in the acquired state.\r
	80	\r
	81	This function checks the state of the spin lock specified by SpinLock. If\r
	82	SpinLock is in the released state, then this function places SpinLock in the\r
83	acquired state and returns SpinLock. Otherwise, this function waits\r
84	indefinitely for the spin lock to be released, and then places it in the\r
85	acquired state and returns SpinLock. All state transitions of SpinLock must\r
86	be performed using MP safe mechanisms.\r
87	\r
88	If SpinLock is NULL, then ASSERT().\r
89	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
90	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
91	PcdSpinLockTimeout microseconds, then ASSERT().\r
92	\r
93	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
94	\r
95	@return SpinLock\r
96	\r
97	**/\r
98	SPIN_LOCK *\r
99	EFIAPI\r
100	AcquireSpinLock (\r
101	IN OUT SPIN_LOCK *SpinLock\r
102	)\r
103	{\r
a82da388	104	UINT64 Current;\r
	105	UINT64 Previous;\r
	106	UINT64 Total;\r
	107	UINT64 Start;\r
	108	UINT64 End;\r
	109	UINT64 Timeout;\r
	110	INT64 Cycle;\r
	111	INT64 Delta;\r
e1f414b6	112	\r
e1f414b6	113	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
a82da388	114	//\r
	115	// Get the current timer value\r
	116	//\r
	117	Current = GetPerformanceCounter();\r
	118	\r
	119	//\r
	120	// Initialize local variables\r
	121	//\r
	122	Start = 0;\r
	123	End = 0;\r
	124	Total = 0;\r
	125	\r
	126	//\r
	127	// Retrieve the performance counter properties and compute the number of performance\r
	128	// counter ticks required to reach the timeout\r
	129	//\r
e1f414b6	130	Timeout = DivU64x32 (\r
	131	MultU64x32 (\r
	132	GetPerformanceCounterProperties (&Start, &End),\r
	133	PcdGet32 (PcdSpinLockTimeout)\r
	134	),\r
	135	1000000\r
	136	);\r
a82da388	137	Cycle = End - Start;\r
	138	if (Cycle < 0) {\r
	139	Cycle = -Cycle;\r
	140	}\r
	141	Cycle++;\r
	142	\r
	143	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	144	CpuPause ();\r
	145	Previous = Current;\r
	146	Current = GetPerformanceCounter();\r
	147	Delta = (INT64) (Current - Previous);\r
	148	if (Start > End) {\r
	149	Delta = -Delta;\r
	150	}\r
	151	if (Delta < 0) {\r
	152	Delta += Cycle;\r
	153	}\r
	154	Total += Delta;\r
	155	ASSERT (Total < Timeout);\r
	156	}\r
	157	} else {\r
	158	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	159	CpuPause ();\r
e1f414b6	160	}\r
e1f414b6	161	}\r
	162	return SpinLock;\r
	163	}\r
	164	\r
	165	/**\r
	166	Attempts to place a spin lock in the acquired state.\r
	167	\r
	168	This function checks the state of the spin lock specified by SpinLock. If\r
	169	SpinLock is in the released state, then this function places SpinLock in the\r
	170	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	171	transitions of SpinLock must be performed using MP safe mechanisms.\r
	172	\r
	173	If SpinLock is NULL, then ASSERT().\r
	174	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	175	\r
	176	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	177	\r
	178	@retval TRUE SpinLock was placed in the acquired state.\r
	179	@retval FALSE SpinLock could not be acquired.\r
	180	\r
	181	**/\r
	182	BOOLEAN\r
	183	EFIAPI\r
	184	AcquireSpinLockOrFail (\r
	185	IN OUT SPIN_LOCK *SpinLock\r
	186	)\r
	187	{\r
	188	SPIN_LOCK LockValue;\r
	189	\r
	190	ASSERT (SpinLock != NULL);\r
	191	\r
	192	LockValue = *SpinLock;\r
	193	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
	194	\r
	195	return (BOOLEAN)(\r
	196	InterlockedCompareExchangePointer (\r
	197	(VOID**)SpinLock,\r
	198	(VOID*)SPIN_LOCK_RELEASED,\r
	199	(VOID*)SPIN_LOCK_ACQUIRED\r
	200	) == (VOID*)SPIN_LOCK_RELEASED\r
	201	);\r
	202	}\r
	203	\r
	204	/**\r
	205	Releases a spin lock.\r
	206	\r
	207	This function places the spin lock specified by SpinLock in the release state\r
	208	and returns SpinLock.\r
	209	\r
	210	If SpinLock is NULL, then ASSERT().\r
	211	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	212	\r
	213	@param SpinLock A pointer to the spin lock to release.\r
	214	\r
	215	@return SpinLock\r
	216	\r
	217	**/\r
	218	SPIN_LOCK *\r
	219	EFIAPI\r
	220	ReleaseSpinLock (\r
	221	IN OUT SPIN_LOCK *SpinLock\r
	222	)\r
	223	{\r
	224	SPIN_LOCK LockValue;\r
225	\r
226	ASSERT (SpinLock != NULL);\r
227	\r
228	LockValue = *SpinLock;\r
229	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
230	\r
231	*SpinLock = SPIN_LOCK_RELEASED;\r
232	return SpinLock;\r
233	}\r
234	\r
235	/**\r
236	Performs an atomic increment of an 32-bit unsigned integer.\r
237	\r
238	Performs an atomic increment of the 32-bit unsigned integer specified by\r
239	Value and returns the incremented value. The increment operation must be\r
240	performed using MP safe mechanisms. The state of the return value is not\r
241	guaranteed to be MP safe.\r
242	\r
243	If Value is NULL, then ASSERT().\r
244	\r
245	@param Value A pointer to the 32-bit value to increment.\r
246	\r
247	@return The incremented value.\r
248	\r
249	**/\r
250	UINT32\r
251	EFIAPI\r
252	InterlockedIncrement (\r
253	IN UINT32 *Value\r
254	)\r
255	{\r
256	ASSERT (Value != NULL);\r
257	return InternalSyncIncrement (Value);\r
258	}\r
259	\r
260	/**\r
261	Performs an atomic decrement of an 32-bit unsigned integer.\r
262	\r
263	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
264	Value and returns the decremented value. The decrement operation must be\r
265	performed using MP safe mechanisms. The state of the return value is not\r
266	guaranteed to be MP safe.\r
267	\r
268	If Value is NULL, then ASSERT().\r
269	\r
270	@param Value A pointer to the 32-bit value to decrement.\r
271	\r
272	@return The decremented value.\r
273	\r
274	**/\r
275	UINT32\r
276	EFIAPI\r
277	InterlockedDecrement (\r
278	IN UINT32 *Value\r
279	)\r
280	{\r
281	ASSERT (Value != NULL);\r
282	return InternalSyncDecrement (Value);\r
283	}\r
284	\r
285	/**\r
286	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
287	\r
288	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
289	specified by Value. If Value is equal to CompareValue, then Value is set to \r
290	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
291	then Value is returned. The compare exchange operation must be performed using \r
292	MP safe mechanisms.\r
293	\r
294	If Value is NULL, then ASSERT().\r
295	\r
296	@param Value A pointer to the 32-bit value for the compare exchange\r
297	operation.\r
298	@param CompareValue 32-bit value used in compare operation.\r
299	@param ExchangeValue 32-bit value used in exchange operation.\r
300	\r
301	@return The original *Value before exchange.\r
302	\r
303	**/\r
304	UINT32\r
305	EFIAPI\r
306	InterlockedCompareExchange32 (\r
307	IN OUT UINT32 *Value,\r
308	IN UINT32 CompareValue,\r
309	IN UINT32 ExchangeValue\r
310	)\r
311	{\r
312	ASSERT (Value != NULL);\r
313	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
314	}\r
315	\r
316	/**\r
317	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
318	\r
319	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
320	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
321	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r
322	The compare exchange operation must be performed using MP safe mechanisms.\r
323	\r
324	If Value is NULL, then ASSERT().\r
325	\r
326	@param Value A pointer to the 64-bit value for the compare exchange\r
327	operation.\r
328	@param CompareValue 64-bit value used in compare operation.\r
329	@param ExchangeValue 64-bit value used in exchange operation.\r
330	\r
331	@return The original *Value before exchange.\r
332	\r
333	**/\r
334	UINT64\r
335	EFIAPI\r
336	InterlockedCompareExchange64 (\r
337	IN OUT UINT64 *Value,\r
338	IN UINT64 CompareValue,\r
339	IN UINT64 ExchangeValue\r
340	)\r
341	{\r
342	ASSERT (Value != NULL);\r
343	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
344	}\r
345	\r
346	/**\r
347	Performs an atomic compare exchange operation on a pointer value.\r
348	\r
349	Performs an atomic compare exchange operation on the pointer value specified\r
350	by Value. If Value is equal to CompareValue, then Value is set to\r
351	ExchangeValue and CompareValue is returned. If Value is not equal to\r
352	CompareValue, then Value is returned. The compare exchange operation must be\r
353	performed using MP safe mechanisms.\r
354	\r
355	If Value is NULL, then ASSERT().\r
356	\r
357	@param Value A pointer to the pointer value for the compare exchange\r
358	operation.\r
359	@param CompareValue Pointer value used in compare operation.\r
360	@param ExchangeValue Pointer value used in exchange operation.\r
361	\r
362	**/\r
363	VOID *\r
364	EFIAPI\r
365	InterlockedCompareExchangePointer (\r
366	IN OUT VOID **Value,\r
367	IN VOID *CompareValue,\r
368	IN VOID *ExchangeValue\r
369	)\r
370	{\r
371	UINT8 SizeOfValue;\r
372	\r
373	SizeOfValue = sizeof (*Value);\r
374	\r
375	switch (SizeOfValue) {\r
376	case sizeof (UINT32):\r
377	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
378	(UINT32*)Value,\r
379	(UINT32)(UINTN)CompareValue,\r
380	(UINT32)(UINTN)ExchangeValue\r
381	);\r
382	case sizeof (UINT64):\r
383	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
384	(UINT64*)Value,\r
385	(UINT64)(UINTN)CompareValue,\r
386	(UINT64)(UINTN)ExchangeValue\r
387	);\r
388	default:\r
389	ASSERT (FALSE);\r
390	return NULL;\r
391	}\r
392	}\r