[mirror_edk2.git] / MdePkg / Library / BaseLib / SynchronizationGcc.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
// GCC inline assembly for Read Write Barrier  \r
//\r
#define _ReadWriteBarrier() do { asm volatile ("": : : "memory"); } while(0)\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 release 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 accquired 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 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 (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
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	// GCC inline assembly for Read Write Barrier \r
	24	//\r
	25	#define _ReadWriteBarrier() do { asm volatile ("": : : "memory"); } while(0)\r
	26	\r
	27	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
	28	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
	29	\r
	30	/**\r
	31	Retrieves the architecture specific spin lock alignment requirements for\r
	32	optimal spin lock performance.\r
	33	\r
	34	This function retrieves the spin lock alignment requirements for optimal\r
	35	performance on a given CPU architecture. The spin lock alignment must be a\r
	36	power of two and is returned by this function. If there are no alignment\r
	37	requirements, then 1 must be returned. The spin lock synchronization\r
	38	functions must function correctly if the spin lock size and alignment values\r
	39	returned by this function are not used at all. These values are hints to the\r
	40	consumers of the spin lock synchronization functions to obtain optimal spin\r
	41	lock performance.\r
	42	\r
	43	@return The architecture specific spin lock alignment.\r
	44	\r
	45	**/\r
	46	UINTN\r
	47	EFIAPI\r
	48	GetSpinLockProperties (\r
	49	VOID\r
	50	)\r
	51	{\r
e1f414b6	52	return 32;\r
	53	}\r
	54	\r
	55	/**\r
	56	Initializes a spin lock to the released state and returns the spin lock.\r
	57	\r
	58	This function initializes the spin lock specified by SpinLock to the released\r
	59	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	60	GetSpinLockProperties() to determine the size and alignment requirements for\r
	61	SpinLock.\r
	62	\r
	63	If SpinLock is NULL, then ASSERT().\r
	64	\r
	65	@param SpinLock A pointer to the spin lock to initialize to the released\r
	66	state.\r
	67	\r
38bbd3d9	68	@return SpinLock in release state.\r
e1f414b6	69	\r
	70	**/\r
	71	SPIN_LOCK *\r
	72	EFIAPI\r
	73	InitializeSpinLock (\r
	74	OUT SPIN_LOCK *SpinLock\r
	75	)\r
	76	{\r
	77	ASSERT (SpinLock != NULL);\r
	78	\r
	79	_ReadWriteBarrier();\r
	80	*SpinLock = SPIN_LOCK_RELEASED;\r
	81	_ReadWriteBarrier();\r
	82	\r
	83	return SpinLock;\r
	84	}\r
	85	\r
	86	/**\r
	87	Waits until a spin lock can be placed in the acquired state.\r
	88	\r
	89	This function checks the state of the spin lock specified by SpinLock. If\r
	90	SpinLock is in the released state, then this function places SpinLock in the\r
	91	acquired state and returns SpinLock. Otherwise, this function waits\r
	92	indefinitely for the spin lock to be released, and then places it in the\r
	93	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	94	be performed using MP safe mechanisms.\r
	95	\r
	96	If SpinLock is NULL, then ASSERT().\r
	97	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	98	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	99	PcdSpinLockTimeout microseconds, then ASSERT().\r
	100	\r
	101	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	102	\r
38bbd3d9	103	@return SpinLock accquired lock.\r
e1f414b6	104	\r
	105	**/\r
	106	SPIN_LOCK *\r
	107	EFIAPI\r
	108	AcquireSpinLock (\r
	109	IN OUT SPIN_LOCK *SpinLock\r
	110	)\r
	111	{\r
a82da388	112	UINT64 Current;\r
	113	UINT64 Previous;\r
	114	UINT64 Total;\r
	115	UINT64 Start;\r
	116	UINT64 End;\r
	117	UINT64 Timeout;\r
	118	INT64 Cycle;\r
	119	INT64 Delta;\r
e1f414b6	120	\r
e1f414b6	121	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
a82da388	122	//\r
	123	// Get the current timer value\r
	124	//\r
	125	Current = GetPerformanceCounter();\r
	126	\r
	127	//\r
	128	// Initialize local variables\r
	129	//\r
	130	Start = 0;\r
	131	End = 0;\r
	132	Total = 0;\r
	133	\r
	134	//\r
	135	// Retrieve the performance counter properties and compute the number of performance\r
	136	// counter ticks required to reach the timeout\r
	137	//\r
e1f414b6	138	Timeout = DivU64x32 (\r
	139	MultU64x32 (\r
	140	GetPerformanceCounterProperties (&Start, &End),\r
	141	PcdGet32 (PcdSpinLockTimeout)\r
	142	),\r
	143	1000000\r
	144	);\r
a82da388	145	Cycle = End - Start;\r
	146	if (Cycle < 0) {\r
	147	Cycle = -Cycle;\r
	148	}\r
	149	Cycle++;\r
	150	\r
	151	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	152	CpuPause ();\r
	153	Previous = Current;\r
	154	Current = GetPerformanceCounter();\r
	155	Delta = (INT64) (Current - Previous);\r
	156	if (Start > End) {\r
	157	Delta = -Delta;\r
	158	}\r
	159	if (Delta < 0) {\r
	160	Delta += Cycle;\r
	161	}\r
	162	Total += Delta;\r
	163	ASSERT (Total < Timeout);\r
	164	}\r
	165	} else {\r
	166	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	167	CpuPause ();\r
e1f414b6	168	}\r
e1f414b6	169	}\r
	170	return SpinLock;\r
	171	}\r
	172	\r
	173	/**\r
	174	Attempts to place a spin lock in the acquired state.\r
	175	\r
	176	This function checks the state of the spin lock specified by SpinLock. If\r
	177	SpinLock is in the released state, then this function places SpinLock in the\r
	178	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	179	transitions of SpinLock must be performed using MP safe mechanisms.\r
	180	\r
	181	If SpinLock is NULL, then ASSERT().\r
	182	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	183	\r
	184	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	185	\r
	186	@retval TRUE SpinLock was placed in the acquired state.\r
	187	@retval FALSE SpinLock could not be acquired.\r
	188	\r
	189	**/\r
	190	BOOLEAN\r
	191	EFIAPI\r
	192	AcquireSpinLockOrFail (\r
	193	IN OUT SPIN_LOCK *SpinLock\r
	194	)\r
	195	{\r
	196	SPIN_LOCK LockValue;\r
	197	VOID *Result;\r
	198	\r
	199	ASSERT (SpinLock != NULL);\r
	200	\r
	201	LockValue = *SpinLock;\r
	202	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
	203	\r
	204	_ReadWriteBarrier ();\r
	205	Result = InterlockedCompareExchangePointer (\r
	206	(VOID**)SpinLock,\r
	207	(VOID*)SPIN_LOCK_RELEASED,\r
	208	(VOID*)SPIN_LOCK_ACQUIRED\r
	209	);\r
	210	\r
	211	_ReadWriteBarrier ();\r
	212	return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);\r
	213	}\r
	214	\r
	215	/**\r
	216	Releases a spin lock.\r
	217	\r
	218	This function places the spin lock specified by SpinLock in the release state\r
	219	and returns SpinLock.\r
	220	\r
	221	If SpinLock is NULL, then ASSERT().\r
	222	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	223	\r
	224	@param SpinLock A pointer to the spin lock to release.\r
	225	\r
38bbd3d9	226	@return SpinLock released lock.\r
e1f414b6	227	\r
	228	**/\r
	229	SPIN_LOCK *\r
	230	EFIAPI\r
	231	ReleaseSpinLock (\r
	232	IN OUT SPIN_LOCK *SpinLock\r
	233	)\r
	234	{\r
	235	SPIN_LOCK LockValue;\r
	236	\r
	237	ASSERT (SpinLock != NULL);\r
	238	\r
	239	LockValue = *SpinLock;\r
	240	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
	241	\r
	242	_ReadWriteBarrier ();\r
	243	*SpinLock = SPIN_LOCK_RELEASED;\r
	244	_ReadWriteBarrier ();\r
	245	\r
	246	return SpinLock;\r
	247	}\r
	248	\r
	249	/**\r
	250	Performs an atomic increment of an 32-bit unsigned integer.\r
	251	\r
	252	Performs an atomic increment of the 32-bit unsigned integer specified by\r
	253	Value and returns the incremented value. The increment operation must be\r
	254	performed using MP safe mechanisms. The state of the return value is not\r
	255	guaranteed to be MP safe.\r
	256	\r
	257	If Value is NULL, then ASSERT().\r
	258	\r
	259	@param Value A pointer to the 32-bit value to increment.\r
	260	\r
	261	@return The incremented value.\r
	262	\r
	263	**/\r
	264	UINT32\r
	265	EFIAPI\r
	266	InterlockedIncrement (\r
	267	IN UINT32 *Value\r
	268	)\r
	269	{\r
	270	ASSERT (Value != NULL);\r
	271	return InternalSyncIncrement (Value);\r
	272	}\r
	273	\r
	274	/**\r
	275	Performs an atomic decrement of an 32-bit unsigned integer.\r
	276	\r
	277	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
	278	Value and returns the decremented value. The decrement operation must be\r
	279	performed using MP safe mechanisms. The state of the return value is not\r
	280	guaranteed to be MP safe.\r
	281	\r
	282	If Value is NULL, then ASSERT().\r
	283	\r
	284	@param Value A pointer to the 32-bit value to decrement.\r
	285	\r
	286	@return The decremented value.\r
	287	\r
	288	**/\r
	289	UINT32\r
	290	EFIAPI\r
291	InterlockedDecrement (\r
292	IN UINT32 *Value\r
293	)\r
294	{\r
295	ASSERT (Value != NULL);\r
296	return InternalSyncDecrement (Value);\r
297	}\r
298	\r
299	/**\r
300	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
301	\r
302	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
303	specified by Value. If Value is equal to CompareValue, then Value is set to \r
304	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
305	then Value is returned. The compare exchange operation must be performed using \r
306	MP safe mechanisms.\r
307	\r
308	If Value is NULL, then ASSERT().\r
309	\r
310	@param Value A pointer to the 32-bit value for the compare exchange\r
311	operation.\r
312	@param CompareValue 32-bit value used in compare operation.\r
313	@param ExchangeValue 32-bit value used in exchange operation.\r
314	\r
315	@return The original *Value before exchange.\r
316	\r
317	**/\r
318	UINT32\r
319	EFIAPI\r
320	InterlockedCompareExchange32 (\r
321	IN OUT UINT32 *Value,\r
322	IN UINT32 CompareValue,\r
323	IN UINT32 ExchangeValue\r
324	)\r
325	{\r
326	ASSERT (Value != NULL);\r
327	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
328	}\r
329	\r
330	/**\r
331	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
332	\r
333	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
334	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
335	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r
336	The compare exchange operation must be performed using MP safe mechanisms.\r
337	\r
338	If Value is NULL, then ASSERT().\r
339	\r
340	@param Value A pointer to the 64-bit value for the compare exchange\r
341	operation.\r
342	@param CompareValue 64-bit value used in compare operation.\r
343	@param ExchangeValue 64-bit value used in exchange operation.\r
344	\r
345	@return The original *Value before exchange.\r
346	\r
347	**/\r
348	UINT64\r
349	EFIAPI\r
350	InterlockedCompareExchange64 (\r
351	IN OUT UINT64 *Value,\r
352	IN UINT64 CompareValue,\r
353	IN UINT64 ExchangeValue\r
354	)\r
355	{\r
356	ASSERT (Value != NULL);\r
357	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
358	}\r
359	\r
360	/**\r
361	Performs an atomic compare exchange operation on a pointer value.\r
362	\r
363	Performs an atomic compare exchange operation on the pointer value specified\r
364	by Value. If Value is equal to CompareValue, then Value is set to\r
365	ExchangeValue and CompareValue is returned. If Value is not equal to\r
366	CompareValue, then Value is returned. The compare exchange operation must be\r
367	performed using MP safe mechanisms.\r
368	\r
369	If Value is NULL, then ASSERT().\r
370	\r
371	@param Value A pointer to the pointer value for the compare exchange\r
372	operation.\r
373	@param CompareValue Pointer value used in compare operation.\r
374	@param ExchangeValue Pointer value used in exchange operation.\r
375	\r
38bbd3d9	376	@return The original *Value before exchange.\r
e1f414b6	377	**/\r
	378	VOID *\r
	379	EFIAPI\r
	380	InterlockedCompareExchangePointer (\r
	381	IN OUT VOID **Value,\r
	382	IN VOID *CompareValue,\r
	383	IN VOID *ExchangeValue\r
	384	)\r
	385	{\r
	386	UINT8 SizeOfValue;\r
	387	\r
	388	SizeOfValue = sizeof (*Value);\r
	389	\r
	390	switch (SizeOfValue) {\r
	391	case sizeof (UINT32):\r
	392	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
	393	(UINT32*)Value,\r
	394	(UINT32)(UINTN)CompareValue,\r
	395	(UINT32)(UINTN)ExchangeValue\r
	396	);\r
	397	case sizeof (UINT64):\r
	398	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
	399	(UINT64*)Value,\r
	400	(UINT64)(UINTN)CompareValue,\r
	401	(UINT64)(UINTN)ExchangeValue\r
	402	);\r
	403	default:\r
	404	ASSERT (FALSE);\r
	405	return NULL;\r
	406	}\r
	407	}\r