[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
  SPDX-License-Identifier: BSD-2-Clause-Patent\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
\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
\r
      if (Delta < 0) {\r
        Delta += Cycle;\r
      }\r
\r
      Total += Delta;\r
      ASSERT (Total < Timeout);\r
    }\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
9344f092	5	SPDX-License-Identifier: BSD-2-Clause-Patent\r
720d3c5f	6	\r
	7	**/\r
	8	\r
	9	#include "BaseSynchronizationLibInternals.h"\r
	10	\r
2f88bd3a MK	11	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
2f88bd3a MK	12	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
720d3c5f	13	\r
	14	/**\r
	15	Retrieves the architecture specific spin lock alignment requirements for\r
	16	optimal spin lock performance.\r
	17	\r
	18	This function retrieves the spin lock alignment requirements for optimal\r
9095d37b	19	performance on a given CPU architecture. The spin lock alignment is byte alignment.\r
744265eb	20	It must be a power of two and is returned by this function. If there are no alignment\r
720d3c5f	21	requirements, then 1 must be returned. The spin lock synchronization\r
	22	functions must function correctly if the spin lock size and alignment values\r
	23	returned by this function are not used at all. These values are hints to the\r
	24	consumers of the spin lock synchronization functions to obtain optimal spin\r
	25	lock performance.\r
	26	\r
	27	@return The architecture specific spin lock alignment.\r
	28	\r
	29	**/\r
	30	UINTN\r
	31	EFIAPI\r
	32	GetSpinLockProperties (\r
	33	VOID\r
	34	)\r
	35	{\r
	36	return 32;\r
	37	}\r
	38	\r
	39	/**\r
	40	Initializes a spin lock to the released state and returns the spin lock.\r
	41	\r
	42	This function initializes the spin lock specified by SpinLock to the released\r
	43	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	44	GetSpinLockProperties() to determine the size and alignment requirements for\r
	45	SpinLock.\r
	46	\r
	47	If SpinLock is NULL, then ASSERT().\r
	48	\r
	49	@param SpinLock A pointer to the spin lock to initialize to the released\r
	50	state.\r
	51	\r
2fc59a00	52	@return SpinLock is in release state.\r
720d3c5f	53	\r
	54	**/\r
	55	SPIN_LOCK *\r
	56	EFIAPI\r
	57	InitializeSpinLock (\r
2f88bd3a	58	OUT SPIN_LOCK *SpinLock\r
720d3c5f	59	)\r
	60	{\r
	61	ASSERT (SpinLock != NULL);\r
	62	*SpinLock = SPIN_LOCK_RELEASED;\r
	63	return SpinLock;\r
	64	}\r
	65	\r
	66	/**\r
	67	Waits until a spin lock can be placed in the acquired state.\r
	68	\r
	69	This function checks the state of the spin lock specified by SpinLock. If\r
	70	SpinLock is in the released state, then this function places SpinLock in the\r
	71	acquired state and returns SpinLock. Otherwise, this function waits\r
	72	indefinitely for the spin lock to be released, and then places it in the\r
	73	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	74	be performed using MP safe mechanisms.\r
	75	\r
	76	If SpinLock is NULL, then ASSERT().\r
	77	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	78	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	79	PcdSpinLockTimeout microseconds, then ASSERT().\r
	80	\r
	81	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	82	\r
2fc59a00	83	@return SpinLock acquired the lock.\r
720d3c5f	84	\r
	85	**/\r
	86	SPIN_LOCK *\r
	87	EFIAPI\r
	88	AcquireSpinLock (\r
2f88bd3a	89	IN OUT SPIN_LOCK *SpinLock\r
720d3c5f	90	)\r
	91	{\r
	92	UINT64 Current;\r
	93	UINT64 Previous;\r
	94	UINT64 Total;\r
	95	UINT64 Start;\r
	96	UINT64 End;\r
	97	UINT64 Timeout;\r
	98	INT64 Cycle;\r
	99	INT64 Delta;\r
	100	\r
0f18e1ed JF	101	if (PcdGet32 (PcdSpinLockTimeout) == 0) {\r
	102	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	103	CpuPause ();\r
	104	}\r
	105	} else if (!AcquireSpinLockOrFail (SpinLock)) {\r
720d3c5f	106	//\r
	107	// Get the current timer value\r
	108	//\r
2f88bd3a	109	Current = GetPerformanceCounter ();\r
720d3c5f	110	\r
	111	//\r
	112	// Initialize local variables\r
	113	//\r
	114	Start = 0;\r
	115	End = 0;\r
	116	Total = 0;\r
	117	\r
	118	//\r
	119	// Retrieve the performance counter properties and compute the number of performance\r
	120	// counter ticks required to reach the timeout\r
	121	//\r
	122	Timeout = DivU64x32 (\r
	123	MultU64x32 (\r
	124	GetPerformanceCounterProperties (&Start, &End),\r
	125	PcdGet32 (PcdSpinLockTimeout)\r
	126	),\r
	127	1000000\r
	128	);\r
	129	Cycle = End - Start;\r
	130	if (Cycle < 0) {\r
	131	Cycle = -Cycle;\r
	132	}\r
2f88bd3a	133	\r
720d3c5f	134	Cycle++;\r
	135	\r
	136	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	137	CpuPause ();\r
	138	Previous = Current;\r
2f88bd3a MK	139	Current = GetPerformanceCounter ();\r
2f88bd3a MK	140	Delta = (INT64)(Current - Previous);\r
720d3c5f	141	if (Start > End) {\r
	142	Delta = -Delta;\r
	143	}\r
2f88bd3a	144	\r
720d3c5f	145	if (Delta < 0) {\r
	146	Delta += Cycle;\r
	147	}\r
2f88bd3a	148	\r
720d3c5f	149	Total += Delta;\r
	150	ASSERT (Total < Timeout);\r
	151	}\r
720d3c5f	152	}\r
2f88bd3a	153	\r
720d3c5f	154	return SpinLock;\r
	155	}\r
	156	\r
	157	/**\r
	158	Attempts to place a spin lock in the acquired state.\r
	159	\r
	160	This function checks the state of the spin lock specified by SpinLock. If\r
	161	SpinLock is in the released state, then this function places SpinLock in the\r
	162	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	163	transitions of SpinLock must be performed using MP safe mechanisms.\r
	164	\r
	165	If SpinLock is NULL, then ASSERT().\r
	166	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	167	\r
	168	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	169	\r
	170	@retval TRUE SpinLock was placed in the acquired state.\r
	171	@retval FALSE SpinLock could not be acquired.\r
	172	\r
	173	**/\r
	174	BOOLEAN\r
	175	EFIAPI\r
	176	AcquireSpinLockOrFail (\r
2f88bd3a	177	IN OUT SPIN_LOCK *SpinLock\r
720d3c5f	178	)\r
720d3c5f	179	{\r
2f88bd3a	180	SPIN_LOCK LockValue;\r
720d3c5f	181	\r
	182	ASSERT (SpinLock != NULL);\r
	183	\r
	184	LockValue = *SpinLock;\r
	185	ASSERT (SPIN_LOCK_ACQUIRED == LockValue \|\| SPIN_LOCK_RELEASED == LockValue);\r
	186	\r
	187	return (BOOLEAN)(\r
2f88bd3a MK	188	InterlockedCompareExchangePointer (\r
	189	(VOID **)SpinLock,\r
	190	(VOID *)SPIN_LOCK_RELEASED,\r
	191	(VOID *)SPIN_LOCK_ACQUIRED\r
	192	) == (VOID *)SPIN_LOCK_RELEASED\r
	193	);\r
720d3c5f	194	}\r
	195	\r
	196	/**\r
	197	Releases a spin lock.\r
	198	\r
	199	This function places the spin lock specified by SpinLock in the release state\r
	200	and returns SpinLock.\r
	201	\r
	202	If SpinLock is NULL, then ASSERT().\r
	203	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	204	\r
	205	@param SpinLock A pointer to the spin lock to release.\r
	206	\r
	207	@return SpinLock released lock.\r
	208	\r
	209	**/\r
	210	SPIN_LOCK *\r
	211	EFIAPI\r
	212	ReleaseSpinLock (\r
2f88bd3a	213	IN OUT SPIN_LOCK *SpinLock\r
720d3c5f	214	)\r
720d3c5f	215	{\r
2f88bd3a	216	SPIN_LOCK LockValue;\r
720d3c5f	217	\r
	218	ASSERT (SpinLock != NULL);\r
	219	\r
	220	LockValue = *SpinLock;\r
	221	ASSERT (SPIN_LOCK_ACQUIRED == LockValue \|\| SPIN_LOCK_RELEASED == LockValue);\r
	222	\r
	223	*SpinLock = SPIN_LOCK_RELEASED;\r
	224	return SpinLock;\r
	225	}\r
	226	\r
	227	/**\r
	228	Performs an atomic increment of an 32-bit unsigned integer.\r
	229	\r
	230	Performs an atomic increment of the 32-bit unsigned integer specified by\r
	231	Value and returns the incremented value. The increment operation must be\r
17634d02	232	performed using MP safe mechanisms.\r
720d3c5f	233	\r
	234	If Value is NULL, then ASSERT().\r
	235	\r
	236	@param Value A pointer to the 32-bit value to increment.\r
	237	\r
	238	@return The incremented value.\r
	239	\r
	240	**/\r
	241	UINT32\r
	242	EFIAPI\r
	243	InterlockedIncrement (\r
2f88bd3a	244	IN volatile UINT32 *Value\r
720d3c5f	245	)\r
	246	{\r
	247	ASSERT (Value != NULL);\r
	248	return InternalSyncIncrement (Value);\r
	249	}\r
	250	\r
	251	/**\r
	252	Performs an atomic decrement of an 32-bit unsigned integer.\r
	253	\r
	254	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
	255	Value and returns the decremented value. The decrement operation must be\r
17634d02	256	performed using MP safe mechanisms.\r
720d3c5f	257	\r
	258	If Value is NULL, then ASSERT().\r
	259	\r
	260	@param Value A pointer to the 32-bit value to decrement.\r
	261	\r
	262	@return The decremented value.\r
	263	\r
	264	**/\r
	265	UINT32\r
	266	EFIAPI\r
	267	InterlockedDecrement (\r
2f88bd3a	268	IN volatile UINT32 *Value\r
720d3c5f	269	)\r
	270	{\r
	271	ASSERT (Value != NULL);\r
	272	return InternalSyncDecrement (Value);\r
	273	}\r
	274	\r
9b89163e AB	275	/**\r
	276	Performs an atomic compare exchange operation on a 16-bit unsigned integer.\r
	277	\r
	278	Performs an atomic compare exchange operation on the 16-bit unsigned integer\r
	279	specified by Value. If Value is equal to CompareValue, then Value is set to\r
	280	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
	281	then Value is returned. The compare exchange operation must be performed using\r
	282	MP safe mechanisms.\r
	283	\r
	284	If Value is NULL, then ASSERT().\r
	285	\r
	286	@param Value A pointer to the 16-bit value for the compare exchange\r
	287	operation.\r
	288	@param CompareValue 16-bit value used in compare operation.\r
	289	@param ExchangeValue 16-bit value used in exchange operation.\r
	290	\r
	291	@return The original *Value before exchange.\r
	292	\r
	293	**/\r
	294	UINT16\r
	295	EFIAPI\r
	296	InterlockedCompareExchange16 (\r
2f88bd3a MK	297	IN OUT volatile UINT16 *Value,\r
	298	IN UINT16 CompareValue,\r
	299	IN UINT16 ExchangeValue\r
9b89163e AB	300	)\r
	301	{\r
	302	ASSERT (Value != NULL);\r
	303	return InternalSyncCompareExchange16 (Value, CompareValue, ExchangeValue);\r
	304	}\r
	305	\r
720d3c5f	306	/**\r
	307	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
	308	\r
	309	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
	310	specified by Value. If Value is equal to CompareValue, then Value is set to\r
	311	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
	312	then Value is returned. The compare exchange operation must be performed using\r
	313	MP safe mechanisms.\r
	314	\r
	315	If Value is NULL, then ASSERT().\r
	316	\r
	317	@param Value A pointer to the 32-bit value for the compare exchange\r
	318	operation.\r
	319	@param CompareValue 32-bit value used in compare operation.\r
	320	@param ExchangeValue 32-bit value used in exchange operation.\r
	321	\r
	322	@return The original *Value before exchange.\r
	323	\r
	324	**/\r
	325	UINT32\r
	326	EFIAPI\r
	327	InterlockedCompareExchange32 (\r
2f88bd3a MK	328	IN OUT volatile UINT32 *Value,\r
	329	IN UINT32 CompareValue,\r
	330	IN UINT32 ExchangeValue\r
720d3c5f	331	)\r
	332	{\r
	333	ASSERT (Value != NULL);\r
	334	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
	335	}\r
	336	\r
	337	/**\r
	338	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
	339	\r
	340	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified\r
	341	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and\r
	342	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.\r
	343	The compare exchange operation must be performed using MP safe mechanisms.\r
	344	\r
	345	If Value is NULL, then ASSERT().\r
	346	\r
	347	@param Value A pointer to the 64-bit value for the compare exchange\r
	348	operation.\r
	349	@param CompareValue 64-bit value used in compare operation.\r
	350	@param ExchangeValue 64-bit value used in exchange operation.\r
	351	\r
	352	@return The original *Value before exchange.\r
	353	\r
	354	**/\r
	355	UINT64\r
	356	EFIAPI\r
	357	InterlockedCompareExchange64 (\r
2f88bd3a MK	358	IN OUT volatile UINT64 *Value,\r
	359	IN UINT64 CompareValue,\r
	360	IN UINT64 ExchangeValue\r
720d3c5f	361	)\r
	362	{\r
	363	ASSERT (Value != NULL);\r
	364	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
	365	}\r
	366	\r
	367	/**\r
	368	Performs an atomic compare exchange operation on a pointer value.\r
	369	\r
	370	Performs an atomic compare exchange operation on the pointer value specified\r
	371	by Value. If Value is equal to CompareValue, then Value is set to\r
	372	ExchangeValue and CompareValue is returned. If Value is not equal to\r
	373	CompareValue, then Value is returned. The compare exchange operation must be\r
	374	performed using MP safe mechanisms.\r
	375	\r
	376	If Value is NULL, then ASSERT().\r
	377	\r
	378	@param Value A pointer to the pointer value for the compare exchange\r
	379	operation.\r
	380	@param CompareValue Pointer value used in compare operation.\r
	381	@param ExchangeValue Pointer value used in exchange operation.\r
	382	\r
	383	@return The original *Value before exchange.\r
	384	**/\r
	385	VOID *\r
	386	EFIAPI\r
	387	InterlockedCompareExchangePointer (\r
2f88bd3a MK	388	IN OUT VOID volatile Value,\r
	389	IN VOID *CompareValue,\r
	390	IN VOID *ExchangeValue\r
720d3c5f	391	)\r
	392	{\r
	393	UINT8 SizeOfValue;\r
	394	\r
	395	SizeOfValue = sizeof (*Value);\r
	396	\r
	397	switch (SizeOfValue) {\r
	398	case sizeof (UINT32):\r
2f88bd3a MK	399	return (VOID *)(UINTN)InterlockedCompareExchange32 (\r
	400	(volatile UINT32 *)Value,\r
	401	(UINT32)(UINTN)CompareValue,\r
	402	(UINT32)(UINTN)ExchangeValue\r
	403	);\r
720d3c5f	404	case sizeof (UINT64):\r
2f88bd3a MK	405	return (VOID *)(UINTN)InterlockedCompareExchange64 (\r
	406	(volatile UINT64 *)Value,\r
	407	(UINT64)(UINTN)CompareValue,\r
	408	(UINT64)(UINTN)ExchangeValue\r
	409	);\r
720d3c5f	410	default:\r
	411	ASSERT (FALSE);\r
	412	return NULL;\r
	413	}\r
	414	}\r