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

/** @file\r
  Implementation of synchronization functions.\r
\r
  Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>\r
  This program and the accompanying materials\r
  are licensed and made available under the terms and conditions of the BSD License\r
  which accompanies this distribution.  The full text of the license may be found at\r
  http://opensource.org/licenses/bsd-license.php.\r
\r
  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
\r
**/\r
\r
#include "BaseSynchronizationLibInternals.h"\r
\r
#define SPIN_LOCK_RELEASED          ((UINTN) 1)\r
#define SPIN_LOCK_ACQUIRED          ((UINTN) 2)\r
\r
/**\r
  Retrieves the architecture specific spin lock alignment requirements for\r
  optimal spin lock performance.\r
\r
  This function retrieves the spin lock alignment requirements for optimal\r
  performance on a given CPU architecture. The spin lock alignment is byte alignment.\r
  It must be a power of two and is returned by this function. If there are no alignment\r
  requirements, then 1 must be returned. The spin lock synchronization\r
  functions must function correctly if the spin lock size and alignment values\r
  returned by this function are not used at all. These values are hints to the\r
  consumers of the spin lock synchronization functions to obtain optimal spin\r
  lock performance.\r
\r
  @return The architecture specific spin lock alignment.\r
\r
**/\r
UINTN\r
EFIAPI\r
GetSpinLockProperties (\r
  VOID\r
  )\r
{\r
  return 32;\r
}\r
\r
/**\r
  Initializes a spin lock to the released state and returns the spin lock.\r
\r
  This function initializes the spin lock specified by SpinLock to the released\r
  state, and returns SpinLock. Optimal performance can be achieved by calling\r
  GetSpinLockProperties() to determine the size and alignment requirements for\r
  SpinLock.\r
\r
  If SpinLock is NULL, then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to initialize to the released\r
                    state.\r
\r
  @return SpinLock is in release state.\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
InitializeSpinLock (\r
  OUT      SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  ASSERT (SpinLock != NULL);\r
  *SpinLock = SPIN_LOCK_RELEASED;\r
  return SpinLock;\r
}\r
\r
/**\r
  Waits until a spin lock can be placed in the acquired state.\r
\r
  This function checks the state of the spin lock specified by SpinLock. If\r
  SpinLock is in the released state, then this function places SpinLock in the\r
  acquired state and returns SpinLock. Otherwise, this function waits\r
  indefinitely for the spin lock to be released, and then places it in the\r
  acquired state and returns SpinLock. All state transitions of SpinLock must\r
  be performed using MP safe mechanisms.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
  If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
  PcdSpinLockTimeout microseconds, then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
\r
  @return SpinLock acquired the lock.\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
AcquireSpinLock (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  UINT64  Current;\r
  UINT64  Previous;\r
  UINT64  Total;\r
  UINT64  Start;\r
  UINT64  End;\r
  UINT64  Timeout;\r
  INT64   Cycle;\r
  INT64   Delta;\r
\r
  if (PcdGet32 (PcdSpinLockTimeout) == 0) {\r
    while (!AcquireSpinLockOrFail (SpinLock)) {\r
      CpuPause ();\r
    }\r
  } else if (!AcquireSpinLockOrFail (SpinLock)) {\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
  }\r
  return SpinLock;\r
}\r
\r
/**\r
  Attempts to place a spin lock in the acquired state.\r
\r
  This function checks the state of the spin lock specified by SpinLock. If\r
  SpinLock is in the released state, then this function places SpinLock in the\r
  acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
  transitions of SpinLock must be performed using MP safe mechanisms.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
\r
  @retval TRUE  SpinLock was placed in the acquired state.\r
  @retval FALSE SpinLock could not be acquired.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
AcquireSpinLockOrFail (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  SPIN_LOCK    LockValue;\r
\r
  ASSERT (SpinLock != NULL);\r
\r
  LockValue = *SpinLock;\r
  ASSERT (SPIN_LOCK_ACQUIRED == LockValue || SPIN_LOCK_RELEASED == LockValue);\r
\r
  return (BOOLEAN)(\r
           InterlockedCompareExchangePointer (\r
             (VOID**)SpinLock,\r
             (VOID*)SPIN_LOCK_RELEASED,\r
             (VOID*)SPIN_LOCK_ACQUIRED\r
             ) == (VOID*)SPIN_LOCK_RELEASED\r
           );\r
}\r
\r
/**\r
  Releases a spin lock.\r
\r
  This function places the spin lock specified by SpinLock in the release state\r
  and returns SpinLock.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to release.\r
\r
  @return SpinLock released lock.\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
ReleaseSpinLock (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  SPIN_LOCK    LockValue;\r
\r
  ASSERT (SpinLock != NULL);\r
\r
  LockValue = *SpinLock;\r
  ASSERT (SPIN_LOCK_ACQUIRED == LockValue || SPIN_LOCK_RELEASED == LockValue);\r
\r
  *SpinLock = SPIN_LOCK_RELEASED;\r
  return SpinLock;\r
}\r
\r
/**\r
  Performs an atomic increment of an 32-bit unsigned integer.\r
\r
  Performs an atomic increment of the 32-bit unsigned integer specified by\r
  Value and returns the incremented value. The increment operation must be\r
  performed using MP safe mechanisms.\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      volatile 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.\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      volatile UINT32           *Value\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncDecrement (Value);\r
}\r
\r
/**\r
  Performs an atomic compare exchange operation on a 16-bit unsigned integer.\r
\r
  Performs an atomic compare exchange operation on the 16-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 16-bit value for the compare exchange\r
                        operation.\r
  @param  CompareValue  16-bit value used in compare operation.\r
  @param  ExchangeValue 16-bit value used in exchange operation.\r
\r
  @return The original *Value before exchange.\r
\r
**/\r
UINT16\r
EFIAPI\r
InterlockedCompareExchange16 (\r
  IN OUT  volatile UINT16           *Value,\r
  IN      UINT16                    CompareValue,\r
  IN      UINT16                    ExchangeValue\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue);\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  volatile 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  volatile UINT64           *Value,\r
  IN      UINT64                    CompareValue,\r
  IN      UINT64                    ExchangeValue\r
  )\r
{\r
  ASSERT (Value != NULL);\r
  return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
}\r
\r
/**\r
  Performs an atomic compare exchange operation on a pointer value.\r
\r
  Performs an atomic compare exchange operation on the pointer value specified\r
  by Value. If Value is equal to CompareValue, then Value is set to\r
  ExchangeValue and CompareValue is returned. If Value is not equal to\r
  CompareValue, then Value is returned. The compare exchange operation must be\r
  performed using MP safe mechanisms.\r
\r
  If Value is NULL, then ASSERT().\r
\r
  @param  Value         A pointer to the pointer value for the compare exchange\r
                        operation.\r
  @param  CompareValue  Pointer value used in compare operation.\r
  @param  ExchangeValue Pointer value used in exchange operation.\r
\r
  @return The original *Value before exchange.\r
**/\r
VOID *\r
EFIAPI\r
InterlockedCompareExchangePointer (\r
  IN OUT  VOID                      * volatile *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
                             (volatile UINT32 *)Value,\r
                             (UINT32)(UINTN)CompareValue,\r
                             (UINT32)(UINTN)ExchangeValue\r
                             );\r
    case sizeof (UINT64):\r
      return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
                             (volatile UINT64 *)Value,\r
                             (UINT64)(UINTN)CompareValue,\r
                             (UINT64)(UINTN)ExchangeValue\r
                             );\r
    default:\r
      ASSERT (FALSE);\r
      return NULL;\r
  }\r
}\r
Commit	Line	Data
720d3c5f	1	/** @file\r
	2	Implementation of synchronization functions.\r
	3	\r
9095d37b	4	Copyright (c) 2006 - 2018, Intel Corporation. All rights reserved.<BR>\r
e2d9bfb2	5	This program and the accompanying materials\r
720d3c5f	6	are licensed and made available under the terms and conditions of the BSD License\r
720d3c5f	7	which accompanies this distribution. The full text of the license may be found at\r
2fc59a00	8	http://opensource.org/licenses/bsd-license.php.\r
720d3c5f	9	\r
	10	THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
	11	WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
	12	\r
	13	**/\r
	14	\r
	15	#include "BaseSynchronizationLibInternals.h"\r
	16	\r
	17	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
	18	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
	19	\r
	20	/**\r
	21	Retrieves the architecture specific spin lock alignment requirements for\r
	22	optimal spin lock performance.\r
	23	\r
	24	This function retrieves the spin lock alignment requirements for optimal\r
9095d37b	25	performance on a given CPU architecture. The spin lock alignment is byte alignment.\r
744265eb	26	It must be a power of two and is returned by this function. If there are no alignment\r
720d3c5f	27	requirements, then 1 must be returned. The spin lock synchronization\r
	28	functions must function correctly if the spin lock size and alignment values\r
	29	returned by this function are not used at all. These values are hints to the\r
	30	consumers of the spin lock synchronization functions to obtain optimal spin\r
	31	lock performance.\r
	32	\r
	33	@return The architecture specific spin lock alignment.\r
	34	\r
	35	**/\r
	36	UINTN\r
	37	EFIAPI\r
	38	GetSpinLockProperties (\r
	39	VOID\r
	40	)\r
	41	{\r
	42	return 32;\r
	43	}\r
	44	\r
	45	/**\r
	46	Initializes a spin lock to the released state and returns the spin lock.\r
	47	\r
	48	This function initializes the spin lock specified by SpinLock to the released\r
	49	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	50	GetSpinLockProperties() to determine the size and alignment requirements for\r
	51	SpinLock.\r
	52	\r
	53	If SpinLock is NULL, then ASSERT().\r
	54	\r
	55	@param SpinLock A pointer to the spin lock to initialize to the released\r
	56	state.\r
	57	\r
2fc59a00	58	@return SpinLock is in release state.\r
720d3c5f	59	\r
	60	**/\r
	61	SPIN_LOCK *\r
	62	EFIAPI\r
	63	InitializeSpinLock (\r
	64	OUT SPIN_LOCK *SpinLock\r
	65	)\r
	66	{\r
	67	ASSERT (SpinLock != NULL);\r
	68	*SpinLock = SPIN_LOCK_RELEASED;\r
	69	return SpinLock;\r
	70	}\r
	71	\r
	72	/**\r
	73	Waits until a spin lock can be placed in the acquired state.\r
	74	\r
	75	This function checks the state of the spin lock specified by SpinLock. If\r
	76	SpinLock is in the released state, then this function places SpinLock in the\r
	77	acquired state and returns SpinLock. Otherwise, this function waits\r
	78	indefinitely for the spin lock to be released, and then places it in the\r
	79	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	80	be performed using MP safe mechanisms.\r
	81	\r
	82	If SpinLock is NULL, then ASSERT().\r
	83	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	84	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	85	PcdSpinLockTimeout microseconds, then ASSERT().\r
	86	\r
	87	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	88	\r
2fc59a00	89	@return SpinLock acquired the lock.\r
720d3c5f	90	\r
	91	**/\r
	92	SPIN_LOCK *\r
	93	EFIAPI\r
	94	AcquireSpinLock (\r
	95	IN OUT SPIN_LOCK *SpinLock\r
	96	)\r
	97	{\r
	98	UINT64 Current;\r
	99	UINT64 Previous;\r
	100	UINT64 Total;\r
	101	UINT64 Start;\r
	102	UINT64 End;\r
	103	UINT64 Timeout;\r
	104	INT64 Cycle;\r
	105	INT64 Delta;\r
	106	\r
0f18e1ed JF	107	if (PcdGet32 (PcdSpinLockTimeout) == 0) {\r
	108	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	109	CpuPause ();\r
	110	}\r
	111	} else if (!AcquireSpinLockOrFail (SpinLock)) {\r
720d3c5f	112	//\r
	113	// Get the current timer value\r
	114	//\r
	115	Current = GetPerformanceCounter();\r
	116	\r
	117	//\r
	118	// Initialize local variables\r
	119	//\r
	120	Start = 0;\r
	121	End = 0;\r
	122	Total = 0;\r
	123	\r
	124	//\r
	125	// Retrieve the performance counter properties and compute the number of performance\r
	126	// counter ticks required to reach the timeout\r
	127	//\r
	128	Timeout = DivU64x32 (\r
	129	MultU64x32 (\r
	130	GetPerformanceCounterProperties (&Start, &End),\r
	131	PcdGet32 (PcdSpinLockTimeout)\r
	132	),\r
	133	1000000\r
	134	);\r
	135	Cycle = End - Start;\r
	136	if (Cycle < 0) {\r
	137	Cycle = -Cycle;\r
	138	}\r
	139	Cycle++;\r
	140	\r
	141	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	142	CpuPause ();\r
	143	Previous = Current;\r
	144	Current = GetPerformanceCounter();\r
	145	Delta = (INT64) (Current - Previous);\r
	146	if (Start > End) {\r
	147	Delta = -Delta;\r
	148	}\r
	149	if (Delta < 0) {\r
	150	Delta += Cycle;\r
	151	}\r
	152	Total += Delta;\r
	153	ASSERT (Total < Timeout);\r
	154	}\r
720d3c5f	155	}\r
	156	return SpinLock;\r
	157	}\r
	158	\r
	159	/**\r
	160	Attempts to place a spin lock in the acquired state.\r
	161	\r
	162	This function checks the state of the spin lock specified by SpinLock. If\r
	163	SpinLock is in the released state, then this function places SpinLock in the\r
	164	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	165	transitions of SpinLock must be performed using MP safe mechanisms.\r
	166	\r
	167	If SpinLock is NULL, then ASSERT().\r
	168	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	169	\r
	170	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	171	\r
	172	@retval TRUE SpinLock was placed in the acquired state.\r
	173	@retval FALSE SpinLock could not be acquired.\r
	174	\r
	175	**/\r
	176	BOOLEAN\r
	177	EFIAPI\r
	178	AcquireSpinLockOrFail (\r
	179	IN OUT SPIN_LOCK *SpinLock\r
	180	)\r
	181	{\r
	182	SPIN_LOCK LockValue;\r
	183	\r
	184	ASSERT (SpinLock != NULL);\r
	185	\r
	186	LockValue = *SpinLock;\r
	187	ASSERT (SPIN_LOCK_ACQUIRED == LockValue \|\| SPIN_LOCK_RELEASED == LockValue);\r
	188	\r
	189	return (BOOLEAN)(\r
	190	InterlockedCompareExchangePointer (\r
	191	(VOID**)SpinLock,\r
	192	(VOID*)SPIN_LOCK_RELEASED,\r
	193	(VOID*)SPIN_LOCK_ACQUIRED\r
	194	) == (VOID*)SPIN_LOCK_RELEASED\r
	195	);\r
	196	}\r
	197	\r
	198	/**\r
	199	Releases a spin lock.\r
	200	\r
	201	This function places the spin lock specified by SpinLock in the release state\r
	202	and returns SpinLock.\r
	203	\r
	204	If SpinLock is NULL, then ASSERT().\r
	205	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	206	\r
	207	@param SpinLock A pointer to the spin lock to release.\r
	208	\r
	209	@return SpinLock released lock.\r
	210	\r
	211	**/\r
	212	SPIN_LOCK *\r
	213	EFIAPI\r
	214	ReleaseSpinLock (\r
	215	IN OUT SPIN_LOCK *SpinLock\r
	216	)\r
	217	{\r
	218	SPIN_LOCK LockValue;\r
219	\r
220	ASSERT (SpinLock != NULL);\r
221	\r
222	LockValue = *SpinLock;\r
223	ASSERT (SPIN_LOCK_ACQUIRED == LockValue \|\| SPIN_LOCK_RELEASED == LockValue);\r
224	\r
225	*SpinLock = SPIN_LOCK_RELEASED;\r
226	return SpinLock;\r
227	}\r
228	\r
229	/**\r
230	Performs an atomic increment of an 32-bit unsigned integer.\r
231	\r
232	Performs an atomic increment of the 32-bit unsigned integer specified by\r
233	Value and returns the incremented value. The increment operation must be\r
17634d02	234	performed using MP safe mechanisms.\r
720d3c5f	235	\r
	236	If Value is NULL, then ASSERT().\r
	237	\r
	238	@param Value A pointer to the 32-bit value to increment.\r
	239	\r
	240	@return The incremented value.\r
	241	\r
	242	**/\r
	243	UINT32\r
	244	EFIAPI\r
	245	InterlockedIncrement (\r
4cee954e	246	IN volatile UINT32 *Value\r
720d3c5f	247	)\r
	248	{\r
	249	ASSERT (Value != NULL);\r
	250	return InternalSyncIncrement (Value);\r
	251	}\r
	252	\r
	253	/**\r
	254	Performs an atomic decrement of an 32-bit unsigned integer.\r
	255	\r
	256	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
	257	Value and returns the decremented value. The decrement operation must be\r
17634d02	258	performed using MP safe mechanisms.\r
720d3c5f	259	\r
	260	If Value is NULL, then ASSERT().\r
	261	\r
	262	@param Value A pointer to the 32-bit value to decrement.\r
	263	\r
	264	@return The decremented value.\r
	265	\r
	266	**/\r
	267	UINT32\r
	268	EFIAPI\r
	269	InterlockedDecrement (\r
4cee954e	270	IN volatile UINT32 *Value\r
720d3c5f	271	)\r
	272	{\r
	273	ASSERT (Value != NULL);\r
	274	return InternalSyncDecrement (Value);\r
	275	}\r
	276	\r
9b89163e AB	277	/**\r
	278	Performs an atomic compare exchange operation on a 16-bit unsigned integer.\r
	279	\r
	280	Performs an atomic compare exchange operation on the 16-bit unsigned integer\r
	281	specified by Value. If Value is equal to CompareValue, then Value is set to\r
	282	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
	283	then Value is returned. The compare exchange operation must be performed using\r
	284	MP safe mechanisms.\r
	285	\r
	286	If Value is NULL, then ASSERT().\r
	287	\r
	288	@param Value A pointer to the 16-bit value for the compare exchange\r
	289	operation.\r
	290	@param CompareValue 16-bit value used in compare operation.\r
	291	@param ExchangeValue 16-bit value used in exchange operation.\r
	292	\r
	293	@return The original *Value before exchange.\r
	294	\r
	295	**/\r
	296	UINT16\r
	297	EFIAPI\r
	298	InterlockedCompareExchange16 (\r
4cee954e	299	IN OUT volatile UINT16 *Value,\r
9b89163e AB	300	IN UINT16 CompareValue,\r
	301	IN UINT16 ExchangeValue\r
	302	)\r
	303	{\r
	304	ASSERT (Value != NULL);\r
	305	return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue);\r
	306	}\r
	307	\r
720d3c5f	308	/**\r
	309	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
	310	\r
	311	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
	312	specified by Value. If Value is equal to CompareValue, then Value is set to\r
	313	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
	314	then Value is returned. The compare exchange operation must be performed using\r
	315	MP safe mechanisms.\r
	316	\r
	317	If Value is NULL, then ASSERT().\r
	318	\r
	319	@param Value A pointer to the 32-bit value for the compare exchange\r
	320	operation.\r
	321	@param CompareValue 32-bit value used in compare operation.\r
	322	@param ExchangeValue 32-bit value used in exchange operation.\r
	323	\r
	324	@return The original *Value before exchange.\r
	325	\r
	326	**/\r
	327	UINT32\r
	328	EFIAPI\r
	329	InterlockedCompareExchange32 (\r
4cee954e	330	IN OUT volatile UINT32 *Value,\r
720d3c5f	331	IN UINT32 CompareValue,\r
	332	IN UINT32 ExchangeValue\r
	333	)\r
	334	{\r
	335	ASSERT (Value != NULL);\r
	336	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
	337	}\r
	338	\r
	339	/**\r
	340	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
	341	\r
	342	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified\r
	343	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and\r
	344	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.\r
	345	The compare exchange operation must be performed using MP safe mechanisms.\r
	346	\r
	347	If Value is NULL, then ASSERT().\r
	348	\r
	349	@param Value A pointer to the 64-bit value for the compare exchange\r
	350	operation.\r
	351	@param CompareValue 64-bit value used in compare operation.\r
	352	@param ExchangeValue 64-bit value used in exchange operation.\r
	353	\r
	354	@return The original *Value before exchange.\r
	355	\r
	356	**/\r
	357	UINT64\r
	358	EFIAPI\r
	359	InterlockedCompareExchange64 (\r
4cee954e	360	IN OUT volatile UINT64 *Value,\r
720d3c5f	361	IN UINT64 CompareValue,\r
	362	IN UINT64 ExchangeValue\r
	363	)\r
	364	{\r
	365	ASSERT (Value != NULL);\r
	366	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
	367	}\r
	368	\r
	369	/**\r
	370	Performs an atomic compare exchange operation on a pointer value.\r
	371	\r
	372	Performs an atomic compare exchange operation on the pointer value specified\r
	373	by Value. If Value is equal to CompareValue, then Value is set to\r
	374	ExchangeValue and CompareValue is returned. If Value is not equal to\r
	375	CompareValue, then Value is returned. The compare exchange operation must be\r
	376	performed using MP safe mechanisms.\r
	377	\r
	378	If Value is NULL, then ASSERT().\r
	379	\r
	380	@param Value A pointer to the pointer value for the compare exchange\r
	381	operation.\r
	382	@param CompareValue Pointer value used in compare operation.\r
	383	@param ExchangeValue Pointer value used in exchange operation.\r
	384	\r
	385	@return The original *Value before exchange.\r
	386	**/\r
	387	VOID *\r
	388	EFIAPI\r
	389	InterlockedCompareExchangePointer (\r
4cee954e	390	IN OUT VOID * volatile *Value,\r
720d3c5f	391	IN VOID *CompareValue,\r
	392	IN VOID *ExchangeValue\r
	393	)\r
	394	{\r
	395	UINT8 SizeOfValue;\r
	396	\r
	397	SizeOfValue = sizeof (*Value);\r
	398	\r
	399	switch (SizeOfValue) {\r
	400	case sizeof (UINT32):\r
	401	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
4cee954e	402	(volatile UINT32 *)Value,\r
720d3c5f	403	(UINT32)(UINTN)CompareValue,\r
	404	(UINT32)(UINTN)ExchangeValue\r
	405	);\r
	406	case sizeof (UINT64):\r
	407	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
4cee954e	408	(volatile UINT64 *)Value,\r
720d3c5f	409	(UINT64)(UINTN)CompareValue,\r
	410	(UINT64)(UINTN)ExchangeValue\r
	411	);\r
	412	default:\r
	413	ASSERT (FALSE);\r
	414	return NULL;\r
	415	}\r
	416	}\r