[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
  Module Name:  SynchronizationGcc.c\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
  // @bug May use a PCD entry to determine this alignment.\r
  return 32;\r
}\r
\r
/**\r
  Initializes a spin lock to the released state and returns the spin lock.\r
\r
  This function initializes the spin lock specified by SpinLock to the released\r
  state, and returns SpinLock. Optimal performance can be achieved by calling\r
  GetSpinLockProperties() to determine the size and alignment requirements for\r
  SpinLock.\r
\r
  If SpinLock is NULL, then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to initialize to the released\r
                    state.\r
\r
  @return SpinLock\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
InitializeSpinLock (\r
  OUT     SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  ASSERT (SpinLock != NULL);\r
\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\r
\r
**/\r
SPIN_LOCK *\r
EFIAPI\r
AcquireSpinLock (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  UINT64                            Tick;\r
  UINT64                            Start, End;\r
  UINT64                            Timeout;\r
\r
  Tick = 0;\r
  Start = 0;\r
  End = 0;\r
  if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
    Tick = GetPerformanceCounter ();\r
    Timeout = DivU64x32 (\r
                MultU64x32 (\r
                  GetPerformanceCounterProperties (&Start, &End),\r
                  PcdGet32 (PcdSpinLockTimeout)\r
                  ),\r
                1000000\r
                );\r
    if (Start < End) {\r
      Tick += Timeout;\r
    } else {\r
      Tick -= Timeout;\r
    }\r
  }\r
\r
  while (!AcquireSpinLockOrFail (SpinLock)) {\r
    CpuPause ();\r
    ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r
  }\r
  return SpinLock;\r
}\r
\r
/**\r
  Attempts to place a spin lock in the acquired state.\r
\r
  This function checks the state of the spin lock specified by SpinLock. If\r
  SpinLock is in the released state, then this function places SpinLock in the\r
  acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
  transitions of SpinLock must be performed using MP safe mechanisms.\r
\r
  If SpinLock is NULL, then ASSERT().\r
  If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
\r
  @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
\r
  @retval TRUE  SpinLock was placed in the acquired state.\r
  @retval FALSE SpinLock could not be acquired.\r
\r
**/\r
BOOLEAN\r
EFIAPI\r
AcquireSpinLockOrFail (\r
  IN OUT  SPIN_LOCK                 *SpinLock\r
  )\r
{\r
  SPIN_LOCK   LockValue;\r
  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\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
**/\r
VOID *\r
EFIAPI\r
InterlockedCompareExchangePointer (\r
  IN OUT  VOID                      **Value,\r
  IN      VOID                      *CompareValue,\r
  IN      VOID                      *ExchangeValue\r
  )\r
{\r
  UINT8  SizeOfValue;\r
\r
  SizeOfValue = sizeof (*Value);\r
\r
  switch (SizeOfValue) {\r
    case sizeof (UINT32):\r
      return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
                             (UINT32*)Value,\r
                             (UINT32)(UINTN)CompareValue,\r
                             (UINT32)(UINTN)ExchangeValue\r
                             );\r
    case sizeof (UINT64):\r
      return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
                             (UINT64*)Value,\r
                             (UINT64)(UINTN)CompareValue,\r
                             (UINT64)(UINTN)ExchangeValue\r
                             );\r
    default:\r
      ASSERT (FALSE);\r
      return NULL;\r
  }\r
}\r
Commit	Line	Data
878ddf1f	1	/** @file\r
	2	Implementation of synchronization functions.\r
	3	\r
ef7baf58	4	Copyright (c) 2006 - 2007, Intel Corporation<BR>\r
878ddf1f	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
ef7baf58	13	Module Name: SynchronizationGcc.c\r
878ddf1f	14	\r
	15	**/\r
	16	\r
58251024	17	#include "BaseLibInternals.h"\r
58251024	18	\r
eb9603a0	19	//\r
ef7baf58	20	// GCC inline assembly for Read Write Barrier \r
eb9603a0	21	//\r
ef7baf58	22	#define _ReadWriteBarrier() do { asm volatile ("": : : "memory"); } while(0)\r
ef7baf58	23	\r
46dd23b8	24	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
46dd23b8	25	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
878ddf1f	26	\r
878ddf1f	27	/**\r
	28	Retrieves the architecture specific spin lock alignment requirements for\r
	29	optimal spin lock performance.\r
	30	\r
	31	This function retrieves the spin lock alignment requirements for optimal\r
	32	performance on a given CPU architecture. The spin lock alignment must be a\r
	33	power of two and is returned by this function. If there are no alignment\r
	34	requirements, then 1 must be returned. The spin lock synchronization\r
	35	functions must function correctly if the spin lock size and alignment values\r
	36	returned by this function are not used at all. These values are hints to the\r
	37	consumers of the spin lock synchronization functions to obtain optimal spin\r
	38	lock performance.\r
	39	\r
	40	@return The architecture specific spin lock alignment.\r
	41	\r
	42	**/\r
	43	UINTN\r
	44	EFIAPI\r
	45	GetSpinLockProperties (\r
	46	VOID\r
	47	)\r
	48	{\r
	49	// @bug May use a PCD entry to determine this alignment.\r
	50	return 32;\r
	51	}\r
	52	\r
	53	/**\r
	54	Initializes a spin lock to the released state and returns the spin lock.\r
	55	\r
	56	This function initializes the spin lock specified by SpinLock to the released\r
	57	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	58	GetSpinLockProperties() to determine the size and alignment requirements for\r
	59	SpinLock.\r
	60	\r
	61	If SpinLock is NULL, then ASSERT().\r
	62	\r
	63	@param SpinLock A pointer to the spin lock to initialize to the released\r
	64	state.\r
	65	\r
	66	@return SpinLock\r
	67	\r
	68	**/\r
	69	SPIN_LOCK *\r
	70	EFIAPI\r
	71	InitializeSpinLock (\r
	72	OUT SPIN_LOCK *SpinLock\r
	73	)\r
	74	{\r
	75	ASSERT (SpinLock != NULL);\r
ef7baf58	76	\r
ef7baf58	77	_ReadWriteBarrier();\r
27787243	78	*SpinLock = SPIN_LOCK_RELEASED;\r
ef7baf58	79	_ReadWriteBarrier();\r
ef7baf58	80	\r
878ddf1f	81	return SpinLock;\r
	82	}\r
	83	\r
	84	/**\r
	85	Waits until a spin lock can be placed in the acquired state.\r
	86	\r
	87	This function checks the state of the spin lock specified by SpinLock. If\r
	88	SpinLock is in the released state, then this function places SpinLock in the\r
	89	acquired state and returns SpinLock. Otherwise, this function waits\r
	90	indefinitely for the spin lock to be released, and then places it in the\r
	91	acquired state and returns SpinLock. All state transitions of SpinLock must\r
	92	be performed using MP safe mechanisms.\r
	93	\r
	94	If SpinLock is NULL, then ASSERT().\r
	95	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	96	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
	97	PcdSpinLockTimeout microseconds, then ASSERT().\r
	98	\r
	99	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	100	\r
	101	@return SpinLock\r
	102	\r
	103	**/\r
	104	SPIN_LOCK *\r
	105	EFIAPI\r
	106	AcquireSpinLock (\r
	107	IN OUT SPIN_LOCK *SpinLock\r
	108	)\r
	109	{\r
	110	UINT64 Tick;\r
	111	UINT64 Start, End;\r
	112	UINT64 Timeout;\r
	113	\r
	114	Tick = 0;\r
	115	Start = 0;\r
	116	End = 0;\r
dc530c7b	117	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
878ddf1f	118	Tick = GetPerformanceCounter ();\r
	119	Timeout = DivU64x32 (\r
	120	MultU64x32 (\r
	121	GetPerformanceCounterProperties (&Start, &End),\r
dc530c7b	122	PcdGet32 (PcdSpinLockTimeout)\r
878ddf1f	123	),\r
	124	1000000\r
	125	);\r
	126	if (Start < End) {\r
	127	Tick += Timeout;\r
	128	} else {\r
	129	Tick -= Timeout;\r
	130	}\r
	131	}\r
	132	\r
	133	while (!AcquireSpinLockOrFail (SpinLock)) {\r
	134	CpuPause ();\r
	135	ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r
	136	}\r
	137	return SpinLock;\r
	138	}\r
	139	\r
	140	/**\r
	141	Attempts to place a spin lock in the acquired state.\r
	142	\r
	143	This function checks the state of the spin lock specified by SpinLock. If\r
	144	SpinLock is in the released state, then this function places SpinLock in the\r
	145	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
	146	transitions of SpinLock must be performed using MP safe mechanisms.\r
	147	\r
	148	If SpinLock is NULL, then ASSERT().\r
	149	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	150	\r
	151	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
	152	\r
	153	@retval TRUE SpinLock was placed in the acquired state.\r
	154	@retval FALSE SpinLock could not be acquired.\r
	155	\r
	156	**/\r
	157	BOOLEAN\r
	158	EFIAPI\r
	159	AcquireSpinLockOrFail (\r
	160	IN OUT SPIN_LOCK *SpinLock\r
	161	)\r
	162	{\r
a4e9aab9	163	SPIN_LOCK LockValue;\r
a4e9aab9	164	VOID *Result;\r
ef7baf58	165	\r
878ddf1f	166	ASSERT (SpinLock != NULL);\r
a4e9aab9	167	\r
	168	LockValue = *SpinLock;\r
	169	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
c9708ddd	170	\r
ef7baf58	171	_ReadWriteBarrier ();\r
ef7baf58	172	Result = InterlockedCompareExchangePointer (\r
878ddf1f	173	(VOID**)SpinLock,\r
	174	(VOID*)SPIN_LOCK_RELEASED,\r
	175	(VOID*)SPIN_LOCK_ACQUIRED\r
878ddf1f	176	);\r
ef7baf58	177	\r
	178	_ReadWriteBarrier ();\r
	179	return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);\r
878ddf1f	180	}\r
	181	\r
	182	/**\r
	183	Releases a spin lock.\r
	184	\r
	185	This function places the spin lock specified by SpinLock in the release state\r
	186	and returns SpinLock.\r
	187	\r
	188	If SpinLock is NULL, then ASSERT().\r
	189	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
	190	\r
	191	@param SpinLock A pointer to the spin lock to release.\r
	192	\r
	193	@return SpinLock\r
	194	\r
	195	**/\r
	196	SPIN_LOCK *\r
	197	EFIAPI\r
	198	ReleaseSpinLock (\r
	199	IN OUT SPIN_LOCK *SpinLock\r
	200	)\r
	201	{\r
a4e9aab9	202	SPIN_LOCK LockValue;\r
a4e9aab9	203	\r
878ddf1f	204	ASSERT (SpinLock != NULL);\r
a4e9aab9	205	\r
	206	LockValue = *SpinLock;\r
	207	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
c9708ddd	208	\r
ef7baf58	209	_ReadWriteBarrier ();\r
27787243	210	*SpinLock = SPIN_LOCK_RELEASED;\r
ef7baf58	211	_ReadWriteBarrier ();\r
ef7baf58	212	\r
878ddf1f	213	return SpinLock;\r
	214	}\r
	215	\r
	216	/**\r
	217	Performs an atomic increment of an 32-bit unsigned integer.\r
	218	\r
	219	Performs an atomic increment of the 32-bit unsigned integer specified by\r
	220	Value and returns the incremented value. The increment operation must be\r
	221	performed using MP safe mechanisms. The state of the return value is not\r
	222	guaranteed to be MP safe.\r
	223	\r
	224	If Value is NULL, then ASSERT().\r
	225	\r
	226	@param Value A pointer to the 32-bit value to increment.\r
	227	\r
	228	@return The incremented value.\r
	229	\r
	230	**/\r
	231	UINT32\r
	232	EFIAPI\r
	233	InterlockedIncrement (\r
	234	IN UINT32 *Value\r
	235	)\r
	236	{\r
	237	ASSERT (Value != NULL);\r
	238	return InternalSyncIncrement (Value);\r
	239	}\r
	240	\r
	241	/**\r
	242	Performs an atomic decrement of an 32-bit unsigned integer.\r
	243	\r
	244	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
	245	Value and returns the decremented value. The decrement operation must be\r
	246	performed using MP safe mechanisms. The state of the return value is not\r
	247	guaranteed to be MP safe.\r
	248	\r
	249	If Value is NULL, then ASSERT().\r
	250	\r
	251	@param Value A pointer to the 32-bit value to decrement.\r
	252	\r
	253	@return The decremented value.\r
	254	\r
	255	**/\r
	256	UINT32\r
	257	EFIAPI\r
	258	InterlockedDecrement (\r
	259	IN UINT32 *Value\r
	260	)\r
	261	{\r
	262	ASSERT (Value != NULL);\r
	263	return InternalSyncDecrement (Value);\r
	264	}\r
	265	\r
	266	/**\r
	267	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
	268	\r
1ea5ca46	269	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
	270	specified by Value. If Value is equal to CompareValue, then Value is set to \r
	271	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
	272	then Value is returned. The compare exchange operation must be performed using \r
	273	MP safe mechanisms.\r
	274	\r
	275	If Value is NULL, then ASSERT().\r
	276	\r
878ddf1f	277	@param Value A pointer to the 32-bit value for the compare exchange\r
	278	operation.\r
	279	@param CompareValue 32-bit value used in compare operation.\r
	280	@param ExchangeValue 32-bit value used in exchange operation.\r
	281	\r
	282	@return The original *Value before exchange.\r
	283	\r
	284	**/\r
	285	UINT32\r
	286	EFIAPI\r
	287	InterlockedCompareExchange32 (\r
0ffa1286	288	IN OUT UINT32 *Value,\r
878ddf1f	289	IN UINT32 CompareValue,\r
	290	IN UINT32 ExchangeValue\r
	291	)\r
	292	{\r
	293	ASSERT (Value != NULL);\r
	294	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
	295	}\r
	296	\r
	297	/**\r
	298	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
	299	\r
1ea5ca46	300	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified \r
	301	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and \r
	302	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned. \r
	303	The compare exchange operation must be performed using MP safe mechanisms.\r
	304	\r
	305	If Value is NULL, then ASSERT().\r
	306	\r
878ddf1f	307	@param Value A pointer to the 64-bit value for the compare exchange\r
	308	operation.\r
	309	@param CompareValue 64-bit value used in compare operation.\r
	310	@param ExchangeValue 64-bit value used in exchange operation.\r
	311	\r
	312	@return The original *Value before exchange.\r
	313	\r
	314	**/\r
	315	UINT64\r
	316	EFIAPI\r
	317	InterlockedCompareExchange64 (\r
0ffa1286	318	IN OUT UINT64 *Value,\r
878ddf1f	319	IN UINT64 CompareValue,\r
	320	IN UINT64 ExchangeValue\r
	321	)\r
	322	{\r
	323	ASSERT (Value != NULL);\r
	324	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
	325	}\r
	326	\r
	327	/**\r
	328	Performs an atomic compare exchange operation on a pointer value.\r
	329	\r
	330	Performs an atomic compare exchange operation on the pointer value specified\r
	331	by Value. If Value is equal to CompareValue, then Value is set to\r
	332	ExchangeValue and CompareValue is returned. If Value is not equal to\r
	333	CompareValue, then Value is returned. The compare exchange operation must be\r
	334	performed using MP safe mechanisms.\r
	335	\r
	336	If Value is NULL, then ASSERT().\r
	337	\r
	338	@param Value A pointer to the pointer value for the compare exchange\r
	339	operation.\r
	340	@param CompareValue Pointer value used in compare operation.\r
	341	@param ExchangeValue Pointer value used in exchange operation.\r
	342	\r
	343	**/\r
	344	VOID *\r
	345	EFIAPI\r
	346	InterlockedCompareExchangePointer (\r
0ffa1286	347	IN OUT VOID **Value,\r
878ddf1f	348	IN VOID *CompareValue,\r
	349	IN VOID *ExchangeValue\r
	350	)\r
	351	{\r
58251024	352	UINT8 SizeOfValue;\r
	353	\r
	354	SizeOfValue = sizeof (*Value);\r
	355	\r
	356	switch (SizeOfValue) {\r
878ddf1f	357	case sizeof (UINT32):\r
	358	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
	359	(UINT32*)Value,\r
	360	(UINT32)(UINTN)CompareValue,\r
	361	(UINT32)(UINTN)ExchangeValue\r
	362	);\r
	363	case sizeof (UINT64):\r
	364	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
	365	(UINT64*)Value,\r
	366	(UINT64)(UINTN)CompareValue,\r
	367	(UINT64)(UINTN)ExchangeValue\r
	368	);\r
	369	default:\r
	370	ASSERT (FALSE);\r
	371	return NULL;\r
	372	}\r
	373	}\r