[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
  Module Name:  Synchronization.c\r
\r
**/\r
\r
#include "BaseLibInternals.h"\r
\r
//\r
// SPIN_LOCK_RELEASED & SPIN_LOCK_ACQUIRED should belong to type "SPIN_LOCK".\r
// Here we use type-case "UINTN" to avoid "volatile" modifier on const integers.\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                            Tick;\r
  UINT64                            Start, End;\r
  UINT64                            Timeout;\r
\r
  Tick = 0;\r
  Start = 0;\r
  End = 0;\r
  if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
    Tick = GetPerformanceCounter ();\r
    Timeout = DivU64x32 (\r
                MultU64x32 (\r
                  GetPerformanceCounterProperties (&Start, &End),\r
                  PcdGet32 (PcdSpinLockTimeout)\r
                  ),\r
                1000000\r
                );\r
    if (Start < End) {\r
      Tick += Timeout;\r
    } else {\r
      Tick -= Timeout;\r
    }\r
  }\r
\r
  while (!AcquireSpinLockOrFail (SpinLock)) {\r
    CpuPause ();\r
    ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\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
878ddf1f	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
	13	Module Name: Synchronization.c\r
	14	\r
	15	**/\r
	16	\r
58251024	17	#include "BaseLibInternals.h"\r
58251024	18	\r
eb9603a0	19	//\r
	20	// SPIN_LOCK_RELEASED & SPIN_LOCK_ACQUIRED should belong to type "SPIN_LOCK".\r
	21	// Here we use type-case "UINTN" to avoid "volatile" modifier on const integers.\r
	22	//\r
46dd23b8	23	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
46dd23b8	24	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
878ddf1f	25	\r
878ddf1f	26	/**\r
	27	Retrieves the architecture specific spin lock alignment requirements for\r
	28	optimal spin lock performance.\r
	29	\r
	30	This function retrieves the spin lock alignment requirements for optimal\r
	31	performance on a given CPU architecture. The spin lock alignment must be a\r
	32	power of two and is returned by this function. If there are no alignment\r
	33	requirements, then 1 must be returned. The spin lock synchronization\r
	34	functions must function correctly if the spin lock size and alignment values\r
	35	returned by this function are not used at all. These values are hints to the\r
	36	consumers of the spin lock synchronization functions to obtain optimal spin\r
	37	lock performance.\r
	38	\r
	39	@return The architecture specific spin lock alignment.\r
	40	\r
	41	**/\r
	42	UINTN\r
	43	EFIAPI\r
	44	GetSpinLockProperties (\r
	45	VOID\r
	46	)\r
	47	{\r
	48	// @bug May use a PCD entry to determine this alignment.\r
	49	return 32;\r
	50	}\r
	51	\r
	52	/**\r
	53	Initializes a spin lock to the released state and returns the spin lock.\r
	54	\r
	55	This function initializes the spin lock specified by SpinLock to the released\r
	56	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	57	GetSpinLockProperties() to determine the size and alignment requirements for\r
	58	SpinLock.\r
	59	\r
	60	If SpinLock is NULL, then ASSERT().\r
	61	\r
	62	@param SpinLock A pointer to the spin lock to initialize to the released\r
	63	state.\r
	64	\r
	65	@return SpinLock\r
	66	\r
	67	**/\r
	68	SPIN_LOCK *\r
	69	EFIAPI\r
	70	InitializeSpinLock (\r
	71	OUT SPIN_LOCK *SpinLock\r
	72	)\r
	73	{\r
	74	ASSERT (SpinLock != NULL);\r
27787243	75	*SpinLock = SPIN_LOCK_RELEASED;\r
878ddf1f	76	return SpinLock;\r
	77	}\r
	78	\r
	79	/**\r
	80	Waits until a spin lock can be placed in the acquired state.\r
	81	\r
	82	This function checks the state of the spin lock specified by SpinLock. If\r
	83	SpinLock is in the released state, then this function places SpinLock in the\r
	84	acquired state and returns SpinLock. Otherwise, this function waits\r
	85	indefinitely for the spin lock to be released, and then places it in the\r
	86	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	87	be performed using MP safe mechanisms.\r
	88	\r
	89	If SpinLock is NULL, then ASSERT().\r
	90	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	91	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	92	PcdSpinLockTimeout microseconds, then ASSERT().\r
	93	\r
	94	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	95	\r
	96	@return SpinLock\r
	97	\r
	98	**/\r
	99	SPIN_LOCK *\r
	100	EFIAPI\r
	101	AcquireSpinLock (\r
	102	IN OUT SPIN_LOCK *SpinLock\r
	103	)\r
	104	{\r
	105	UINT64 Tick;\r
	106	UINT64 Start, End;\r
	107	UINT64 Timeout;\r
	108	\r
	109	Tick = 0;\r
	110	Start = 0;\r
	111	End = 0;\r
dc530c7b	112	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
878ddf1f	113	Tick = GetPerformanceCounter ();\r
	114	Timeout = DivU64x32 (\r
	115	MultU64x32 (\r
	116	GetPerformanceCounterProperties (&Start, &End),\r
dc530c7b	117	PcdGet32 (PcdSpinLockTimeout)\r
878ddf1f	118	),\r
	119	1000000\r
	120	);\r
	121	if (Start < End) {\r
	122	Tick += Timeout;\r
	123	} else {\r
	124	Tick -= Timeout;\r
	125	}\r
	126	}\r
	127	\r
	128	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	129	CpuPause ();\r
	130	ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r
	131	}\r
	132	return SpinLock;\r
	133	}\r
	134	\r
	135	/**\r
	136	Attempts to place a spin lock in the acquired state.\r
	137	\r
	138	This function checks the state of the spin lock specified by SpinLock. If\r
	139	SpinLock is in the released state, then this function places SpinLock in the\r
	140	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	141	transitions of SpinLock must be performed using MP safe mechanisms.\r
	142	\r
	143	If SpinLock is NULL, then ASSERT().\r
	144	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	145	\r
	146	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	147	\r
	148	@retval TRUE SpinLock was placed in the acquired state.\r
	149	@retval FALSE SpinLock could not be acquired.\r
	150	\r
	151	**/\r
	152	BOOLEAN\r
	153	EFIAPI\r
	154	AcquireSpinLockOrFail (\r
	155	IN OUT SPIN_LOCK *SpinLock\r
	156	)\r
	157	{\r
46dd23b8	158	SPIN_LOCK LockValue;\r
c9708ddd	159	\r
878ddf1f	160	ASSERT (SpinLock != NULL);\r
c9708ddd	161	\r
	162	LockValue = *SpinLock;\r
	163	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
	164	\r
878ddf1f	165	return (BOOLEAN)(\r
	166	InterlockedCompareExchangePointer (\r
	167	(VOID**)SpinLock,\r
	168	(VOID*)SPIN_LOCK_RELEASED,\r
	169	(VOID*)SPIN_LOCK_ACQUIRED\r
	170	) == (VOID*)SPIN_LOCK_RELEASED\r
	171	);\r
	172	}\r
	173	\r
	174	/**\r
	175	Releases a spin lock.\r
	176	\r
	177	This function places the spin lock specified by SpinLock in the release state\r
	178	and returns SpinLock.\r
	179	\r
	180	If SpinLock is NULL, then ASSERT().\r
	181	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	182	\r
	183	@param SpinLock A pointer to the spin lock to release.\r
	184	\r
	185	@return SpinLock\r
	186	\r
	187	**/\r
	188	SPIN_LOCK *\r
	189	EFIAPI\r
	190	ReleaseSpinLock (\r
	191	IN OUT SPIN_LOCK *SpinLock\r
	192	)\r
	193	{\r
46dd23b8	194	SPIN_LOCK LockValue;\r
c9708ddd	195	\r
878ddf1f	196	ASSERT (SpinLock != NULL);\r
c9708ddd	197	\r
	198	LockValue = *SpinLock;\r
	199	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
	200	\r
27787243	201	*SpinLock = SPIN_LOCK_RELEASED;\r
878ddf1f	202	return SpinLock;\r
	203	}\r
	204	\r
	205	/**\r
	206	Performs an atomic increment of an 32-bit unsigned integer.\r
	207	\r
	208	Performs an atomic increment of the 32-bit unsigned integer specified by\r
	209	Value and returns the incremented value. The increment operation must be\r
	210	performed using MP safe mechanisms. The state of the return value is not\r
	211	guaranteed to be MP safe.\r
	212	\r
	213	If Value is NULL, then ASSERT().\r
	214	\r
	215	@param Value A pointer to the 32-bit value to increment.\r
	216	\r
	217	@return The incremented value.\r
	218	\r
	219	**/\r
	220	UINT32\r
	221	EFIAPI\r
	222	InterlockedIncrement (\r
	223	IN UINT32 *Value\r
	224	)\r
	225	{\r
	226	ASSERT (Value != NULL);\r
	227	return InternalSyncIncrement (Value);\r
	228	}\r
	229	\r
	230	/**\r
	231	Performs an atomic decrement of an 32-bit unsigned integer.\r
	232	\r
	233	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
	234	Value and returns the decremented value. The decrement operation must be\r
	235	performed using MP safe mechanisms. The state of the return value is not\r
	236	guaranteed to be MP safe.\r
	237	\r
	238	If Value is NULL, then ASSERT().\r
	239	\r
	240	@param Value A pointer to the 32-bit value to decrement.\r
	241	\r
	242	@return The decremented value.\r
	243	\r
	244	**/\r
	245	UINT32\r
	246	EFIAPI\r
	247	InterlockedDecrement (\r
	248	IN UINT32 *Value\r
	249	)\r
	250	{\r
	251	ASSERT (Value != NULL);\r
	252	return InternalSyncDecrement (Value);\r
	253	}\r
	254	\r
	255	/**\r
	256	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
	257	\r
1ea5ca46	258	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
	259	specified by Value. If Value is equal to CompareValue, then Value is set to \r
	260	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
	261	then Value is returned. The compare exchange operation must be performed using \r
	262	MP safe mechanisms.\r
	263	\r
	264	If Value is NULL, then ASSERT().\r
	265	\r
878ddf1f	266	@param Value A pointer to the 32-bit value for the compare exchange\r
	267	operation.\r
	268	@param CompareValue 32-bit value used in compare operation.\r
	269	@param ExchangeValue 32-bit value used in exchange operation.\r
	270	\r
	271	@return The original *Value before exchange.\r
	272	\r
	273	**/\r
	274	UINT32\r
	275	EFIAPI\r
	276	InterlockedCompareExchange32 (\r
0ffa1286	277	IN OUT UINT32 *Value,\r
878ddf1f	278	IN UINT32 CompareValue,\r
	279	IN UINT32 ExchangeValue\r
	280	)\r
	281	{\r
	282	ASSERT (Value != NULL);\r
	283	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
	284	}\r
	285	\r
	286	/**\r
	287	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
	288	\r
1ea5ca46	289	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
	290	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
	291	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r
	292	The compare exchange operation must be performed using MP safe mechanisms.\r
	293	\r
	294	If Value is NULL, then ASSERT().\r
	295	\r
878ddf1f	296	@param Value A pointer to the 64-bit value for the compare exchange\r
	297	operation.\r
	298	@param CompareValue 64-bit value used in compare operation.\r
	299	@param ExchangeValue 64-bit value used in exchange operation.\r
	300	\r
	301	@return The original *Value before exchange.\r
	302	\r
	303	**/\r
	304	UINT64\r
	305	EFIAPI\r
	306	InterlockedCompareExchange64 (\r
0ffa1286	307	IN OUT UINT64 *Value,\r
878ddf1f	308	IN UINT64 CompareValue,\r
	309	IN UINT64 ExchangeValue\r
	310	)\r
	311	{\r
	312	ASSERT (Value != NULL);\r
	313	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
	314	}\r
	315	\r
	316	/**\r
	317	Performs an atomic compare exchange operation on a pointer value.\r
	318	\r
	319	Performs an atomic compare exchange operation on the pointer value specified\r
	320	by Value. If Value is equal to CompareValue, then Value is set to\r
	321	ExchangeValue and CompareValue is returned. If Value is not equal to\r
	322	CompareValue, then Value is returned. The compare exchange operation must be\r
	323	performed using MP safe mechanisms.\r
	324	\r
	325	If Value is NULL, then ASSERT().\r
	326	\r
	327	@param Value A pointer to the pointer value for the compare exchange\r
	328	operation.\r
	329	@param CompareValue Pointer value used in compare operation.\r
	330	@param ExchangeValue Pointer value used in exchange operation.\r
	331	\r
	332	**/\r
	333	VOID *\r
	334	EFIAPI\r
	335	InterlockedCompareExchangePointer (\r
0ffa1286	336	IN OUT VOID **Value,\r
878ddf1f	337	IN VOID *CompareValue,\r
	338	IN VOID *ExchangeValue\r
	339	)\r
	340	{\r
58251024	341	UINT8 SizeOfValue;\r
	342	\r
	343	SizeOfValue = sizeof (*Value);\r
	344	\r
	345	switch (SizeOfValue) {\r
878ddf1f	346	case sizeof (UINT32):\r
	347	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
	348	(UINT32*)Value,\r
	349	(UINT32)(UINTN)CompareValue,\r
	350	(UINT32)(UINTN)ExchangeValue\r
	351	);\r
	352	case sizeof (UINT64):\r
	353	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
	354	(UINT64*)Value,\r
	355	(UINT64)(UINTN)CompareValue,\r
	356	(UINT64)(UINTN)ExchangeValue\r
	357	);\r
	358	default:\r
	359	ASSERT (FALSE);\r
	360	return NULL;\r
	361	}\r
	362	}\r