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

/** @file\r
  Implementation of synchronization functions.\r
\r
  Copyright (c) 2006 - 2007, 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
//\r
// Microsoft Visual Studio 7.1 Function Prototypes for read write barrier Intrinsics\r
//\r
void    _ReadWriteBarrier (void);\r
#pragma intrinsic(_ReadWriteBarrier)\r
\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 in released state.\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
InitializeSpinLock (\r
  OUT     SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  ASSERT (SpinLock != NULL);\r
\r
  _ReadWriteBarrier();\r
  *SpinLock = SPIN_LOCK_RELEASED;\r
  _ReadWriteBarrier();\r
\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 aquiring 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
  VOID        *Result;\r
  \r
  ASSERT (SpinLock != NULL);\r
\r
  LockValue = *SpinLock;\r
  ASSERT (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r
\r
  _ReadWriteBarrier ();\r
  Result = InterlockedCompareExchangePointer (\r
             (VOID**)SpinLock,\r
             (VOID*)SPIN_LOCK_RELEASED,\r
             (VOID*)SPIN_LOCK_ACQUIRED\r
           );\r
\r
  _ReadWriteBarrier ();\r
  return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);\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 releasing 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 (LockValue == SPIN_LOCK_ACQUIRED || LockValue == SPIN_LOCK_RELEASED);\r
\r
  _ReadWriteBarrier ();\r
  *SpinLock = SPIN_LOCK_RELEASED;\r
  _ReadWriteBarrier ();\r
\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 - 2007, 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	//\r
	23	// Microsoft Visual Studio 7.1 Function Prototypes for read write barrier Intrinsics\r
	24	//\r
	25	void _ReadWriteBarrier (void);\r
	26	#pragma intrinsic(_ReadWriteBarrier)\r
	27	\r
	28	\r
	29	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
	30	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
	31	\r
	32	/**\r
	33	Retrieves the architecture specific spin lock alignment requirements for\r
	34	optimal spin lock performance.\r
	35	\r
	36	This function retrieves the spin lock alignment requirements for optimal\r
	37	performance on a given CPU architecture. The spin lock alignment must be a\r
	38	power of two and is returned by this function. If there are no alignment\r
	39	requirements, then 1 must be returned. The spin lock synchronization\r
	40	functions must function correctly if the spin lock size and alignment values\r
	41	returned by this function are not used at all. These values are hints to the\r
	42	consumers of the spin lock synchronization functions to obtain optimal spin\r
	43	lock performance.\r
	44	\r
	45	@return The architecture specific spin lock alignment.\r
	46	\r
	47	**/\r
	48	UINTN\r
	49	EFIAPI\r
	50	GetSpinLockProperties (\r
	51	VOID\r
	52	)\r
	53	{\r
e1f414b6	54	return 32;\r
	55	}\r
	56	\r
	57	/**\r
	58	Initializes a spin lock to the released state and returns the spin lock.\r
	59	\r
	60	This function initializes the spin lock specified by SpinLock to the released\r
	61	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	62	GetSpinLockProperties() to determine the size and alignment requirements for\r
	63	SpinLock.\r
	64	\r
	65	If SpinLock is NULL, then ASSERT().\r
	66	\r
	67	@param SpinLock A pointer to the spin lock to initialize to the released\r
	68	state.\r
	69	\r
38bbd3d9	70	@return SpinLock in released state.\r
e1f414b6	71	\r
	72	**/\r
	73	SPIN_LOCK *\r
	74	EFIAPI\r
	75	InitializeSpinLock (\r
	76	OUT SPIN_LOCK *SpinLock\r
	77	)\r
	78	{\r
	79	ASSERT (SpinLock != NULL);\r
	80	\r
	81	_ReadWriteBarrier();\r
	82	*SpinLock = SPIN_LOCK_RELEASED;\r
	83	_ReadWriteBarrier();\r
	84	\r
	85	return SpinLock;\r
	86	}\r
	87	\r
	88	/**\r
	89	Waits until a spin lock can be placed in the acquired state.\r
	90	\r
	91	This function checks the state of the spin lock specified by SpinLock. If\r
	92	SpinLock is in the released state, then this function places SpinLock in the\r
	93	acquired state and returns SpinLock. Otherwise, this function waits\r
	94	indefinitely for the spin lock to be released, and then places it in the\r
	95	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	96	be performed using MP safe mechanisms.\r
	97	\r
	98	If SpinLock is NULL, then ASSERT().\r
	99	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	100	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	101	PcdSpinLockTimeout microseconds, then ASSERT().\r
	102	\r
	103	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	104	\r
38bbd3d9	105	@return SpinLock aquiring lock.\r
e1f414b6	106	\r
	107	**/\r
	108	SPIN_LOCK *\r
	109	EFIAPI\r
	110	AcquireSpinLock (\r
	111	IN OUT SPIN_LOCK *SpinLock\r
	112	)\r
	113	{\r
a82da388	114	UINT64 Current;\r
	115	UINT64 Previous;\r
	116	UINT64 Total;\r
	117	UINT64 Start;\r
	118	UINT64 End;\r
	119	UINT64 Timeout;\r
	120	INT64 Cycle;\r
	121	INT64 Delta;\r
e1f414b6	122	\r
e1f414b6	123	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
a82da388	124	//\r
	125	// Get the current timer value\r
	126	//\r
	127	Current = GetPerformanceCounter();\r
	128	\r
	129	//\r
	130	// Initialize local variables\r
	131	//\r
	132	Start = 0;\r
	133	End = 0;\r
	134	Total = 0;\r
	135	\r
	136	//\r
	137	// Retrieve the performance counter properties and compute the number of performance\r
	138	// counter ticks required to reach the timeout\r
	139	//\r
e1f414b6	140	Timeout = DivU64x32 (\r
	141	MultU64x32 (\r
	142	GetPerformanceCounterProperties (&Start, &End),\r
	143	PcdGet32 (PcdSpinLockTimeout)\r
	144	),\r
	145	1000000\r
	146	);\r
a82da388	147	Cycle = End - Start;\r
	148	if (Cycle < 0) {\r
	149	Cycle = -Cycle;\r
	150	}\r
	151	Cycle++;\r
	152	\r
	153	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	154	CpuPause ();\r
	155	Previous = Current;\r
	156	Current = GetPerformanceCounter();\r
	157	Delta = (INT64) (Current - Previous);\r
	158	if (Start > End) {\r
	159	Delta = -Delta;\r
	160	}\r
	161	if (Delta < 0) {\r
	162	Delta += Cycle;\r
	163	}\r
	164	Total += Delta;\r
	165	ASSERT (Total < Timeout);\r
	166	}\r
	167	} else {\r
	168	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	169	CpuPause ();\r
e1f414b6	170	}\r
e1f414b6	171	}\r
	172	return SpinLock;\r
	173	}\r
	174	\r
	175	/**\r
	176	Attempts to place a spin lock in the acquired state.\r
	177	\r
	178	This function checks the state of the spin lock specified by SpinLock. If\r
	179	SpinLock is in the released state, then this function places SpinLock in the\r
	180	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	181	transitions of SpinLock must be performed using MP safe mechanisms.\r
	182	\r
	183	If SpinLock is NULL, then ASSERT().\r
	184	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	185	\r
	186	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	187	\r
	188	@retval TRUE SpinLock was placed in the acquired state.\r
	189	@retval FALSE SpinLock could not be acquired.\r
	190	\r
	191	**/\r
	192	BOOLEAN\r
	193	EFIAPI\r
	194	AcquireSpinLockOrFail (\r
	195	IN OUT SPIN_LOCK *SpinLock\r
	196	)\r
	197	{\r
	198	SPIN_LOCK LockValue;\r
	199	VOID *Result;\r
	200	\r
	201	ASSERT (SpinLock != NULL);\r
	202	\r
	203	LockValue = *SpinLock;\r
	204	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
	205	\r
	206	_ReadWriteBarrier ();\r
	207	Result = InterlockedCompareExchangePointer (\r
	208	(VOID**)SpinLock,\r
	209	(VOID*)SPIN_LOCK_RELEASED,\r
	210	(VOID*)SPIN_LOCK_ACQUIRED\r
	211	);\r
	212	\r
	213	_ReadWriteBarrier ();\r
	214	return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);\r
	215	}\r
	216	\r
	217	/**\r
	218	Releases a spin lock.\r
	219	\r
	220	This function places the spin lock specified by SpinLock in the release state\r
	221	and returns SpinLock.\r
	222	\r
	223	If SpinLock is NULL, then ASSERT().\r
	224	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	225	\r
	226	@param SpinLock A pointer to the spin lock to release.\r
	227	\r
38bbd3d9	228	@return SpinLock releasing lock.\r
e1f414b6	229	\r
	230	**/\r
	231	SPIN_LOCK *\r
	232	EFIAPI\r
	233	ReleaseSpinLock (\r
	234	IN OUT SPIN_LOCK *SpinLock\r
	235	)\r
	236	{\r
	237	SPIN_LOCK LockValue;\r
	238	\r
	239	ASSERT (SpinLock != NULL);\r
	240	\r
	241	LockValue = *SpinLock;\r
	242	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
	243	\r
	244	_ReadWriteBarrier ();\r
	245	*SpinLock = SPIN_LOCK_RELEASED;\r
	246	_ReadWriteBarrier ();\r
	247	\r
	248	return SpinLock;\r
	249	}\r
	250	\r
	251	/**\r
	252	Performs an atomic increment of an 32-bit unsigned integer.\r
	253	\r
	254	Performs an atomic increment of the 32-bit unsigned integer specified by\r
	255	Value and returns the incremented value. The increment operation must be\r
	256	performed using MP safe mechanisms. The state of the return value is not\r
	257	guaranteed to be MP safe.\r
	258	\r
	259	If Value is NULL, then ASSERT().\r
	260	\r
	261	@param Value A pointer to the 32-bit value to increment.\r
	262	\r
	263	@return The incremented value.\r
	264	\r
	265	**/\r
	266	UINT32\r
	267	EFIAPI\r
	268	InterlockedIncrement (\r
	269	IN UINT32 *Value\r
	270	)\r
	271	{\r
	272	ASSERT (Value != NULL);\r
	273	return InternalSyncIncrement (Value);\r
	274	}\r
	275	\r
	276	/**\r
	277	Performs an atomic decrement of an 32-bit unsigned integer.\r
	278	\r
	279	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
	280	Value and returns the decremented value. The decrement operation must be\r
	281	performed using MP safe mechanisms. The state of the return value is not\r
	282	guaranteed to be MP safe.\r
	283	\r
	284	If Value is NULL, then ASSERT().\r
	285	\r
	286	@param Value A pointer to the 32-bit value to decrement.\r
	287	\r
	288	@return The decremented value.\r
	289	\r
	290	**/\r
	291	UINT32\r
	292	EFIAPI\r
293	InterlockedDecrement (\r
294	IN UINT32 *Value\r
295	)\r
296	{\r
297	ASSERT (Value != NULL);\r
298	return InternalSyncDecrement (Value);\r
299	}\r
300	\r
301	/**\r
302	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
303	\r
304	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
305	specified by Value. If Value is equal to CompareValue, then Value is set to \r
306	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
307	then Value is returned. The compare exchange operation must be performed using \r
308	MP safe mechanisms.\r
309	\r
310	If Value is NULL, then ASSERT().\r
311	\r
312	@param Value A pointer to the 32-bit value for the compare exchange\r
313	operation.\r
314	@param CompareValue 32-bit value used in compare operation.\r
315	@param ExchangeValue 32-bit value used in exchange operation.\r
316	\r
317	@return The original *Value before exchange.\r
318	\r
319	**/\r
320	UINT32\r
321	EFIAPI\r
322	InterlockedCompareExchange32 (\r
323	IN OUT UINT32 *Value,\r
324	IN UINT32 CompareValue,\r
325	IN UINT32 ExchangeValue\r
326	)\r
327	{\r
328	ASSERT (Value != NULL);\r
329	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
330	}\r
331	\r
332	/**\r
333	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
334	\r
335	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
336	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
337	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r
338	The compare exchange operation must be performed using MP safe mechanisms.\r
339	\r
340	If Value is NULL, then ASSERT().\r
341	\r
342	@param Value A pointer to the 64-bit value for the compare exchange\r
343	operation.\r
344	@param CompareValue 64-bit value used in compare operation.\r
345	@param ExchangeValue 64-bit value used in exchange operation.\r
346	\r
347	@return The original *Value before exchange.\r
348	\r
349	**/\r
350	UINT64\r
351	EFIAPI\r
352	InterlockedCompareExchange64 (\r
353	IN OUT UINT64 *Value,\r
354	IN UINT64 CompareValue,\r
355	IN UINT64 ExchangeValue\r
356	)\r
357	{\r
358	ASSERT (Value != NULL);\r
359	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
360	}\r
361	\r
362	/**\r
363	Performs an atomic compare exchange operation on a pointer value.\r
364	\r
365	Performs an atomic compare exchange operation on the pointer value specified\r
366	by Value. If Value is equal to CompareValue, then Value is set to\r
367	ExchangeValue and CompareValue is returned. If Value is not equal to\r
368	CompareValue, then Value is returned. The compare exchange operation must be\r
369	performed using MP safe mechanisms.\r
370	\r
371	If Value is NULL, then ASSERT().\r
372	\r
373	@param Value A pointer to the pointer value for the compare exchange\r
374	operation.\r
375	@param CompareValue Pointer value used in compare operation.\r
376	@param ExchangeValue Pointer value used in exchange operation.\r
38bbd3d9	377	\r
38bbd3d9	378	@return The original *Value before exchange.\r
e1f414b6	379	\r
	380	**/\r
	381	VOID *\r
	382	EFIAPI\r
	383	InterlockedCompareExchangePointer (\r
	384	IN OUT VOID **Value,\r
	385	IN VOID *CompareValue,\r
	386	IN VOID *ExchangeValue\r
	387	)\r
	388	{\r
	389	UINT8 SizeOfValue;\r
	390	\r
	391	SizeOfValue = sizeof (*Value);\r
	392	\r
	393	switch (SizeOfValue) {\r
	394	case sizeof (UINT32):\r
	395	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
	396	(UINT32*)Value,\r
	397	(UINT32)(UINTN)CompareValue,\r
	398	(UINT32)(UINTN)ExchangeValue\r
	399	);\r
	400	case sizeof (UINT64):\r
	401	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
	402	(UINT64*)Value,\r
	403	(UINT64)(UINTN)CompareValue,\r
	404	(UINT64)(UINTN)ExchangeValue\r
	405	);\r
	406	default:\r
	407	ASSERT (FALSE);\r
	408	return NULL;\r
	409	}\r
	410	}\r