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

/** @file\r
  Implementation of synchronization functions.\r
\r
  Copyright (c) 2006 - 2008, 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
#include "BaseSynchronizationLibInternals.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 acquired 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
720d3c5f	1	/** @file\r
	2	Implementation of synchronization functions.\r
	3	\r
	4	Copyright (c) 2006 - 2008, 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
	13	**/\r
	14	\r
	15	#include "BaseSynchronizationLibInternals.h"\r
	16	\r
	17	//\r
	18	// GCC inline assembly for Read Write Barrier \r
	19	//\r
	20	#define _ReadWriteBarrier() do { asm volatile ("": : : "memory"); } while(0)\r
	21	\r
	22	#define SPIN_LOCK_RELEASED ((UINTN) 1)\r
	23	#define SPIN_LOCK_ACQUIRED ((UINTN) 2)\r
	24	\r
	25	/**\r
	26	Retrieves the architecture specific spin lock alignment requirements for\r
	27	optimal spin lock performance.\r
	28	\r
	29	This function retrieves the spin lock alignment requirements for optimal\r
	30	performance on a given CPU architecture. The spin lock alignment must be a\r
	31	power of two and is returned by this function. If there are no alignment\r
	32	requirements, then 1 must be returned. The spin lock synchronization\r
	33	functions must function correctly if the spin lock size and alignment values\r
	34	returned by this function are not used at all. These values are hints to the\r
	35	consumers of the spin lock synchronization functions to obtain optimal spin\r
	36	lock performance.\r
	37	\r
	38	@return The architecture specific spin lock alignment.\r
	39	\r
	40	**/\r
	41	UINTN\r
	42	EFIAPI\r
	43	GetSpinLockProperties (\r
	44	VOID\r
	45	)\r
	46	{\r
	47	return 32;\r
	48	}\r
	49	\r
	50	/**\r
	51	Initializes a spin lock to the released state and returns the spin lock.\r
	52	\r
	53	This function initializes the spin lock specified by SpinLock to the released\r
	54	state, and returns SpinLock. Optimal performance can be achieved by calling\r
	55	GetSpinLockProperties() to determine the size and alignment requirements for\r
	56	SpinLock.\r
	57	\r
	58	If SpinLock is NULL, then ASSERT().\r
	59	\r
	60	@param SpinLock A pointer to the spin lock to initialize to the released\r
	61	state.\r
	62	\r
	63	@return SpinLock in release state.\r
	64	\r
65	**/\r
66	SPIN_LOCK *\r
67	EFIAPI\r
68	InitializeSpinLock (\r
69	OUT SPIN_LOCK *SpinLock\r
70	)\r
71	{\r
72	ASSERT (SpinLock != NULL);\r
73	\r
74	_ReadWriteBarrier();\r
75	*SpinLock = SPIN_LOCK_RELEASED;\r
76	_ReadWriteBarrier();\r
77	\r
78	return SpinLock;\r
79	}\r
80	\r
81	/**\r
82	Waits until a spin lock can be placed in the acquired state.\r
83	\r
84	This function checks the state of the spin lock specified by SpinLock. If\r
85	SpinLock is in the released state, then this function places SpinLock in the\r
86	acquired state and returns SpinLock. Otherwise, this function waits\r
87	indefinitely for the spin lock to be released, and then places it in the\r
88	acquired state and returns SpinLock. All state transitions of SpinLock must\r
89	be performed using MP safe mechanisms.\r
90	\r
91	If SpinLock is NULL, then ASSERT().\r
92	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
93	If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in\r
94	PcdSpinLockTimeout microseconds, then ASSERT().\r
95	\r
96	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
97	\r
98	@return SpinLock acquired lock.\r
99	\r
100	**/\r
101	SPIN_LOCK *\r
102	EFIAPI\r
103	AcquireSpinLock (\r
104	IN OUT SPIN_LOCK *SpinLock\r
105	)\r
106	{\r
107	UINT64 Current;\r
108	UINT64 Previous;\r
109	UINT64 Total;\r
110	UINT64 Start;\r
111	UINT64 End;\r
112	UINT64 Timeout;\r
113	INT64 Cycle;\r
114	INT64 Delta;\r
115	\r
116	if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
117	//\r
118	// Get the current timer value\r
119	//\r
120	Current = GetPerformanceCounter();\r
121	\r
122	//\r
123	// Initialize local variables\r
124	//\r
125	Start = 0;\r
126	End = 0;\r
127	Total = 0;\r
128	\r
129	//\r
130	// Retrieve the performance counter properties and compute the number of performance\r
131	// counter ticks required to reach the timeout\r
132	//\r
133	Timeout = DivU64x32 (\r
134	MultU64x32 (\r
135	GetPerformanceCounterProperties (&Start, &End),\r
136	PcdGet32 (PcdSpinLockTimeout)\r
137	),\r
138	1000000\r
139	);\r
140	Cycle = End - Start;\r
141	if (Cycle < 0) {\r
142	Cycle = -Cycle;\r
143	}\r
144	Cycle++;\r
145	\r
146	while (!AcquireSpinLockOrFail (SpinLock)) {\r
147	CpuPause ();\r
148	Previous = Current;\r
149	Current = GetPerformanceCounter();\r
150	Delta = (INT64) (Current - Previous);\r
151	if (Start > End) {\r
152	Delta = -Delta;\r
153	}\r
154	if (Delta < 0) {\r
155	Delta += Cycle;\r
156	}\r
157	Total += Delta;\r
158	ASSERT (Total < Timeout);\r
159	}\r
160	} else {\r
161	while (!AcquireSpinLockOrFail (SpinLock)) {\r
162	CpuPause ();\r
163	}\r
164	}\r
165	return SpinLock;\r
166	}\r
167	\r
168	/**\r
169	Attempts to place a spin lock in the acquired state.\r
170	\r
171	This function checks the state of the spin lock specified by SpinLock. If\r
172	SpinLock is in the released state, then this function places SpinLock in the\r
173	acquired state and returns TRUE. Otherwise, FALSE is returned. All state\r
174	transitions of SpinLock must be performed using MP safe mechanisms.\r
175	\r
176	If SpinLock is NULL, then ASSERT().\r
177	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
178	\r
179	@param SpinLock A pointer to the spin lock to place in the acquired state.\r
180	\r
181	@retval TRUE SpinLock was placed in the acquired state.\r
182	@retval FALSE SpinLock could not be acquired.\r
183	\r
184	**/\r
185	BOOLEAN\r
186	EFIAPI\r
187	AcquireSpinLockOrFail (\r
188	IN OUT SPIN_LOCK *SpinLock\r
189	)\r
190	{\r
191	SPIN_LOCK LockValue;\r
192	VOID *Result;\r
193	\r
194	ASSERT (SpinLock != NULL);\r
195	\r
196	LockValue = *SpinLock;\r
197	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
198	\r
199	_ReadWriteBarrier ();\r
200	Result = InterlockedCompareExchangePointer (\r
201	(VOID**)SpinLock,\r
202	(VOID*)SPIN_LOCK_RELEASED,\r
203	(VOID*)SPIN_LOCK_ACQUIRED\r
204	);\r
205	\r
206	_ReadWriteBarrier ();\r
207	return (BOOLEAN) (Result == (VOID*) SPIN_LOCK_RELEASED);\r
208	}\r
209	\r
210	/**\r
211	Releases a spin lock.\r
212	\r
213	This function places the spin lock specified by SpinLock in the release state\r
214	and returns SpinLock.\r
215	\r
216	If SpinLock is NULL, then ASSERT().\r
217	If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().\r
218	\r
219	@param SpinLock A pointer to the spin lock to release.\r
220	\r
221	@return SpinLock released lock.\r
222	\r
223	**/\r
224	SPIN_LOCK *\r
225	EFIAPI\r
226	ReleaseSpinLock (\r
227	IN OUT SPIN_LOCK *SpinLock\r
228	)\r
229	{\r
230	SPIN_LOCK LockValue;\r
231	\r
232	ASSERT (SpinLock != NULL);\r
233	\r
234	LockValue = *SpinLock;\r
235	ASSERT (LockValue == SPIN_LOCK_ACQUIRED \|\| LockValue == SPIN_LOCK_RELEASED);\r
236	\r
237	_ReadWriteBarrier ();\r
238	*SpinLock = SPIN_LOCK_RELEASED;\r
239	_ReadWriteBarrier ();\r
240	\r
241	return SpinLock;\r
242	}\r
243	\r
244	/**\r
245	Performs an atomic increment of an 32-bit unsigned integer.\r
246	\r
247	Performs an atomic increment of the 32-bit unsigned integer specified by\r
248	Value and returns the incremented value. The increment operation must be\r
249	performed using MP safe mechanisms. The state of the return value is not\r
250	guaranteed to be MP safe.\r
251	\r
252	If Value is NULL, then ASSERT().\r
253	\r
254	@param Value A pointer to the 32-bit value to increment.\r
255	\r
256	@return The incremented value.\r
257	\r
258	**/\r
259	UINT32\r
260	EFIAPI\r
261	InterlockedIncrement (\r
262	IN UINT32 *Value\r
263	)\r
264	{\r
265	ASSERT (Value != NULL);\r
266	return InternalSyncIncrement (Value);\r
267	}\r
268	\r
269	/**\r
270	Performs an atomic decrement of an 32-bit unsigned integer.\r
271	\r
272	Performs an atomic decrement of the 32-bit unsigned integer specified by\r
273	Value and returns the decremented value. The decrement operation must be\r
274	performed using MP safe mechanisms. The state of the return value is not\r
275	guaranteed to be MP safe.\r
276	\r
277	If Value is NULL, then ASSERT().\r
278	\r
279	@param Value A pointer to the 32-bit value to decrement.\r
280	\r
281	@return The decremented value.\r
282	\r
283	**/\r
284	UINT32\r
285	EFIAPI\r
286	InterlockedDecrement (\r
287	IN UINT32 *Value\r
288	)\r
289	{\r
290	ASSERT (Value != NULL);\r
291	return InternalSyncDecrement (Value);\r
292	}\r
293	\r
294	/**\r
295	Performs an atomic compare exchange operation on a 32-bit unsigned integer.\r
296	\r
297	Performs an atomic compare exchange operation on the 32-bit unsigned integer\r
298	specified by Value. If Value is equal to CompareValue, then Value is set to\r
299	ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,\r
300	then Value is returned. The compare exchange operation must be performed using\r
301	MP safe mechanisms.\r
302	\r
303	If Value is NULL, then ASSERT().\r
304	\r
305	@param Value A pointer to the 32-bit value for the compare exchange\r
306	operation.\r
307	@param CompareValue 32-bit value used in compare operation.\r
308	@param ExchangeValue 32-bit value used in exchange operation.\r
309	\r
310	@return The original *Value before exchange.\r
311	\r
312	**/\r
313	UINT32\r
314	EFIAPI\r
315	InterlockedCompareExchange32 (\r
316	IN OUT UINT32 *Value,\r
317	IN UINT32 CompareValue,\r
318	IN UINT32 ExchangeValue\r
319	)\r
320	{\r
321	ASSERT (Value != NULL);\r
322	return InternalSyncCompareExchange32 (Value, CompareValue, ExchangeValue);\r
323	}\r
324	\r
325	/**\r
326	Performs an atomic compare exchange operation on a 64-bit unsigned integer.\r
327	\r
328	Performs an atomic compare exchange operation on the 64-bit unsigned integer specified\r
329	by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and\r
330	CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.\r
331	The compare exchange operation must be performed using MP safe mechanisms.\r
332	\r
333	If Value is NULL, then ASSERT().\r
334	\r
335	@param Value A pointer to the 64-bit value for the compare exchange\r
336	operation.\r
337	@param CompareValue 64-bit value used in compare operation.\r
338	@param ExchangeValue 64-bit value used in exchange operation.\r
339	\r
340	@return The original *Value before exchange.\r
341	\r
342	**/\r
343	UINT64\r
344	EFIAPI\r
345	InterlockedCompareExchange64 (\r
346	IN OUT UINT64 *Value,\r
347	IN UINT64 CompareValue,\r
348	IN UINT64 ExchangeValue\r
349	)\r
350	{\r
351	ASSERT (Value != NULL);\r
352	return InternalSyncCompareExchange64 (Value, CompareValue, ExchangeValue);\r
353	}\r
354	\r
355	/**\r
356	Performs an atomic compare exchange operation on a pointer value.\r
357	\r
358	Performs an atomic compare exchange operation on the pointer value specified\r
359	by Value. If Value is equal to CompareValue, then Value is set to\r
360	ExchangeValue and CompareValue is returned. If Value is not equal to\r
361	CompareValue, then Value is returned. The compare exchange operation must be\r
362	performed using MP safe mechanisms.\r
363	\r
364	If Value is NULL, then ASSERT().\r
365	\r
366	@param Value A pointer to the pointer value for the compare exchange\r
367	operation.\r
368	@param CompareValue Pointer value used in compare operation.\r
369	@param ExchangeValue Pointer value used in exchange operation.\r
370	\r
371	@return The original *Value before exchange.\r
372	**/\r
373	VOID *\r
374	EFIAPI\r
375	InterlockedCompareExchangePointer (\r
376	IN OUT VOID **Value,\r
377	IN VOID *CompareValue,\r
378	IN VOID *ExchangeValue\r
379	)\r
380	{\r
381	UINT8 SizeOfValue;\r
382	\r
383	SizeOfValue = sizeof (*Value);\r
384	\r
385	switch (SizeOfValue) {\r
386	case sizeof (UINT32):\r
387	return (VOID*)(UINTN)InterlockedCompareExchange32 (\r
388	(UINT32*)Value,\r
389	(UINT32)(UINTN)CompareValue,\r
390	(UINT32)(UINTN)ExchangeValue\r
391	);\r
392	case sizeof (UINT64):\r
393	return (VOID*)(UINTN)InterlockedCompareExchange64 (\r
394	(UINT64*)Value,\r
395	(UINT64)(UINTN)CompareValue,\r
396	(UINT64)(UINTN)ExchangeValue\r
397	);\r
398	default:\r
399	ASSERT (FALSE);\r
400	return NULL;\r
401	}\r
402	}\r