[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
  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 initialized 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 aquired 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\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
**/\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
e1f414b6	47	return 32;\r
	48	}\r
	49	\r
	50	/**\r
	51	Initializes a spin lock to the released state and returns the spin lock.\r
	52	\r
	53	This function initializes the spin lock specified by SpinLock to the released\r
	54	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	55	GetSpinLockProperties() to determine the size and alignment requirements for\r
	56	SpinLock.\r
	57	\r
	58	If SpinLock is NULL, then ASSERT().\r
	59	\r
	60	@param SpinLock A pointer to the spin lock to initialize to the released\r
	61	state.\r
	62	\r
38bbd3d9	63	@return SpinLock initialized in release state.\r
e1f414b6	64	\r
	65	**/\r
	66	SPIN_LOCK *\r
	67	EFIAPI\r
	68	InitializeSpinLock (\r
	69	OUT SPIN_LOCK *SpinLock\r
	70	)\r
	71	{\r
	72	ASSERT (SpinLock != NULL);\r
	73	*SpinLock = SPIN_LOCK_RELEASED;\r
	74	return SpinLock;\r
	75	}\r
	76	\r
	77	/**\r
	78	Waits until a spin lock can be placed in the acquired state.\r
	79	\r
	80	This function checks the state of the spin lock specified by SpinLock. If\r
	81	SpinLock is in the released state, then this function places SpinLock in the\r
	82	acquired state and returns SpinLock. Otherwise, this function waits\r
	83	indefinitely for the spin lock to be released, and then places it in the\r
	84	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	85	be performed using MP safe mechanisms.\r
	86	\r
	87	If SpinLock is NULL, then ASSERT().\r
	88	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	89	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	90	PcdSpinLockTimeout microseconds, then ASSERT().\r
	91	\r
	92	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	93	\r
38bbd3d9	94	@return SpinLock aquired lock.\r
e1f414b6	95	\r
	96	**/\r
	97	SPIN_LOCK *\r
	98	EFIAPI\r
	99	AcquireSpinLock (\r
	100	IN OUT SPIN_LOCK *SpinLock\r
	101	)\r
	102	{\r
a82da388	103	UINT64 Current;\r
	104	UINT64 Previous;\r
	105	UINT64 Total;\r
	106	UINT64 Start;\r
	107	UINT64 End;\r
	108	UINT64 Timeout;\r
	109	INT64 Cycle;\r
	110	INT64 Delta;\r
e1f414b6	111	\r
e1f414b6	112	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
a82da388	113	//\r
	114	// Get the current timer value\r
	115	//\r
	116	Current = GetPerformanceCounter();\r
	117	\r
	118	//\r
	119	// Initialize local variables\r
	120	//\r
	121	Start = 0;\r
	122	End = 0;\r
	123	Total = 0;\r
	124	\r
	125	//\r
	126	// Retrieve the performance counter properties and compute the number of performance\r
	127	// counter ticks required to reach the timeout\r
	128	//\r
e1f414b6	129	Timeout = DivU64x32 (\r
	130	MultU64x32 (\r
	131	GetPerformanceCounterProperties (&Start, &End),\r
	132	PcdGet32 (PcdSpinLockTimeout)\r
	133	),\r
	134	1000000\r
	135	);\r
a82da388	136	Cycle = End - Start;\r
	137	if (Cycle < 0) {\r
	138	Cycle = -Cycle;\r
	139	}\r
	140	Cycle++;\r
	141	\r
	142	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	143	CpuPause ();\r
	144	Previous = Current;\r
	145	Current = GetPerformanceCounter();\r
	146	Delta = (INT64) (Current - Previous);\r
	147	if (Start > End) {\r
	148	Delta = -Delta;\r
	149	}\r
	150	if (Delta < 0) {\r
	151	Delta += Cycle;\r
	152	}\r
	153	Total += Delta;\r
	154	ASSERT (Total < Timeout);\r
	155	}\r
	156	} else {\r
	157	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	158	CpuPause ();\r
e1f414b6	159	}\r
e1f414b6	160	}\r
	161	return SpinLock;\r
	162	}\r
	163	\r
	164	/**\r
	165	Attempts to place a spin lock in the acquired state.\r
	166	\r
	167	This function checks the state of the spin lock specified by SpinLock. If\r
	168	SpinLock is in the released state, then this function places SpinLock in the\r
	169	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	170	transitions of SpinLock must be performed using MP safe mechanisms.\r
	171	\r
	172	If SpinLock is NULL, then ASSERT().\r
	173	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	174	\r
	175	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	176	\r
	177	@retval TRUE SpinLock was placed in the acquired state.\r
	178	@retval FALSE SpinLock could not be acquired.\r
	179	\r
	180	**/\r
	181	BOOLEAN\r
	182	EFIAPI\r
	183	AcquireSpinLockOrFail (\r
	184	IN OUT SPIN_LOCK *SpinLock\r
	185	)\r
	186	{\r
	187	SPIN_LOCK LockValue;\r
	188	\r
	189	ASSERT (SpinLock != NULL);\r
	190	\r
	191	LockValue = *SpinLock;\r
38bbd3d9	192	ASSERT (SPIN_LOCK_ACQUIRED == LockValue \|\| SPIN_LOCK_RELEASED == LockValue);\r
e1f414b6	193	\r
	194	return (BOOLEAN)(\r
	195	InterlockedCompareExchangePointer (\r
	196	(VOID**)SpinLock,\r
	197	(VOID*)SPIN_LOCK_RELEASED,\r
	198	(VOID*)SPIN_LOCK_ACQUIRED\r
	199	) == (VOID*)SPIN_LOCK_RELEASED\r
	200	);\r
	201	}\r
	202	\r
	203	/**\r
	204	Releases a spin lock.\r
	205	\r
	206	This function places the spin lock specified by SpinLock in the release state\r
	207	and returns SpinLock.\r
	208	\r
	209	If SpinLock is NULL, then ASSERT().\r
	210	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	211	\r
	212	@param SpinLock A pointer to the spin lock to release.\r
	213	\r
	214	@return SpinLock\r
	215	\r
	216	**/\r
	217	SPIN_LOCK *\r
	218	EFIAPI\r
	219	ReleaseSpinLock (\r
	220	IN OUT SPIN_LOCK *SpinLock\r
	221	)\r
	222	{\r
	223	SPIN_LOCK LockValue;\r
	224	\r
	225	ASSERT (SpinLock != NULL);\r
	226	\r
	227	LockValue = *SpinLock;\r
38bbd3d9	228	ASSERT (SPIN_LOCK_ACQUIRED == LockValue \|\| SPIN_LOCK_RELEASED == LockValue);\r
e1f414b6	229	\r
	230	*SpinLock = SPIN_LOCK_RELEASED;\r
	231	return SpinLock;\r
	232	}\r
	233	\r
	234	/**\r
	235	Performs an atomic increment of an 32-bit unsigned integer.\r
	236	\r
	237	Performs an atomic increment of the 32-bit unsigned integer specified by\r
	238	Value and returns the incremented value. The increment operation must be\r
	239	performed using MP safe mechanisms. The state of the return value is not\r
	240	guaranteed to be MP safe.\r
	241	\r
	242	If Value is NULL, then ASSERT().\r
	243	\r
	244	@param Value A pointer to the 32-bit value to increment.\r
	245	\r
	246	@return The incremented value.\r
	247	\r
	248	**/\r
	249	UINT32\r
	250	EFIAPI\r
	251	InterlockedIncrement (\r
	252	IN UINT32 *Value\r
	253	)\r
	254	{\r
	255	ASSERT (Value != NULL);\r
	256	return InternalSyncIncrement (Value);\r
	257	}\r
	258	\r
	259	/**\r
	260	Performs an atomic decrement of an 32-bit unsigned integer.\r
	261	\r
	262	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
	263	Value and returns the decremented value. The decrement operation must be\r
	264	performed using MP safe mechanisms. The state of the return value is not\r
	265	guaranteed to be MP safe.\r
	266	\r
	267	If Value is NULL, then ASSERT().\r
	268	\r
	269	@param Value A pointer to the 32-bit value to decrement.\r
	270	\r
	271	@return The decremented value.\r
	272	\r
	273	**/\r
	274	UINT32\r
	275	EFIAPI\r
	276	InterlockedDecrement (\r
	277	IN UINT32 *Value\r
	278	)\r
	279	{\r
	280	ASSERT (Value != NULL);\r
	281	return InternalSyncDecrement (Value);\r
	282	}\r
	283	\r
	284	/**\r
	285	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
	286	\r
	287	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
	288	specified by Value. If Value is equal to CompareValue, then Value is set to \r
	289	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
	290	then Value is returned. The compare exchange operation must be performed using \r
	291	MP safe mechanisms.\r
	292	\r
293	If Value is NULL, then ASSERT().\r
294	\r
295	@param Value A pointer to the 32-bit value for the compare exchange\r
296	operation.\r
297	@param CompareValue 32-bit value used in compare operation.\r
298	@param ExchangeValue 32-bit value used in exchange operation.\r
299	\r
300	@return The original *Value before exchange.\r
301	\r
302	**/\r
303	UINT32\r
304	EFIAPI\r
305	InterlockedCompareExchange32 (\r
306	IN OUT UINT32 *Value,\r
307	IN UINT32 CompareValue,\r
308	IN UINT32 ExchangeValue\r
309	)\r
310	{\r
311	ASSERT (Value != NULL);\r
312	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
313	}\r
314	\r
315	/**\r
316	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
317	\r
318	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
319	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
320	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r
321	The compare exchange operation must be performed using MP safe mechanisms.\r
322	\r
323	If Value is NULL, then ASSERT().\r
324	\r
325	@param Value A pointer to the 64-bit value for the compare exchange\r
326	operation.\r
327	@param CompareValue 64-bit value used in compare operation.\r
328	@param ExchangeValue 64-bit value used in exchange operation.\r
329	\r
330	@return The original *Value before exchange.\r
331	\r
332	**/\r
333	UINT64\r
334	EFIAPI\r
335	InterlockedCompareExchange64 (\r
336	IN OUT UINT64 *Value,\r
337	IN UINT64 CompareValue,\r
338	IN UINT64 ExchangeValue\r
339	)\r
340	{\r
341	ASSERT (Value != NULL);\r
342	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
343	}\r
344	\r
345	/**\r
346	Performs an atomic compare exchange operation on a pointer value.\r
347	\r
348	Performs an atomic compare exchange operation on the pointer value specified\r
349	by Value. If Value is equal to CompareValue, then Value is set to\r
350	ExchangeValue and CompareValue is returned. If Value is not equal to\r
351	CompareValue, then Value is returned. The compare exchange operation must be\r
352	performed using MP safe mechanisms.\r
353	\r
354	If Value is NULL, then ASSERT().\r
355	\r
356	@param Value A pointer to the pointer value for the compare exchange\r
357	operation.\r
358	@param CompareValue Pointer value used in compare operation.\r
359	@param ExchangeValue Pointer value used in exchange operation.\r
38bbd3d9	360	\r
38bbd3d9	361	@return The original *Value before exchange.\r
e1f414b6	362	\r
	363	**/\r
	364	VOID *\r
	365	EFIAPI\r
	366	InterlockedCompareExchangePointer (\r
	367	IN OUT VOID **Value,\r
	368	IN VOID *CompareValue,\r
	369	IN VOID *ExchangeValue\r
	370	)\r
	371	{\r
	372	UINT8 SizeOfValue;\r
	373	\r
	374	SizeOfValue = sizeof (*Value);\r
	375	\r
	376	switch (SizeOfValue) {\r
	377	case sizeof (UINT32):\r
	378	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
	379	(UINT32*)Value,\r
	380	(UINT32)(UINTN)CompareValue,\r
	381	(UINT32)(UINTN)ExchangeValue\r
	382	);\r
	383	case sizeof (UINT64):\r
	384	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
	385	(UINT64*)Value,\r
	386	(UINT64)(UINTN)CompareValue,\r
	387	(UINT64)(UINTN)ExchangeValue\r
	388	);\r
	389	default:\r
	390	ASSERT (FALSE);\r
	391	return NULL;\r
	392	}\r
	393	}\r