/** @file
Implementation of synchronization functions.
Copyright (c) 2006 - 2010, Intel Corporation. All rights reserved.<BR>
This program and the accompanying materials
are licensed and made available under the terms and conditions of the BSD License
which accompanies this distribution. The full text of the license may be found at
THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
**/
#include "BaseSynchronizationLibInternals.h"
/**
Retrieves the architecture specific spin lock alignment requirements for
optimal spin lock performance.
This function retrieves the spin lock alignment requirements for optimal
performance on a given CPU architecture. The spin lock alignment must be a
power of two and is returned by this function. If there are no alignment
requirements, then 1 must be returned. The spin lock synchronization
functions must function correctly if the spin lock size and alignment values
returned by this function are not used at all. These values are hints to the
consumers of the spin lock synchronization functions to obtain optimal spin
lock performance.
@return The architecture specific spin lock alignment.
**/
)
{
return 32;
}
/**
Initializes a spin lock to the released state and returns the spin lock.
This function initializes the spin lock specified by SpinLock to the released
state, and returns SpinLock. Optimal performance can be achieved by calling
GetSpinLockProperties() to determine the size and alignment requirements for
SpinLock.
If SpinLock is NULL, then ASSERT().
@param SpinLock A pointer to the spin lock to initialize to the released
state.
@return SpinLock is in release state.
**/
)
{
return SpinLock;
}
/**
Waits until a spin lock can be placed in the acquired state.
This function checks the state of the spin lock specified by SpinLock. If
SpinLock is in the released state, then this function places SpinLock in the
acquired state and returns SpinLock. Otherwise, this function waits
indefinitely for the spin lock to be released, and then places it in the
acquired state and returns SpinLock. All state transitions of SpinLock must
be performed using MP safe mechanisms.
If SpinLock is NULL, then ASSERT().
If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
If PcdSpinLockTimeout is not zero, and SpinLock is can not be acquired in
PcdSpinLockTimeout microseconds, then ASSERT().
@param SpinLock A pointer to the spin lock to place in the acquired state.
@return SpinLock acquired the lock.
**/
)
{
if (PcdGet32 (PcdSpinLockTimeout) > 0) {
//
// Get the current timer value
//
//
// Initialize local variables
//
Start = 0;
End = 0;
Total = 0;
//
// Retrieve the performance counter properties and compute the number of performance
// counter ticks required to reach the timeout
//
),
1000000
);
if (Cycle < 0) {
}
Cycle++;
while (!AcquireSpinLockOrFail (SpinLock)) {
CpuPause ();
}
if (Delta < 0) {
}
}
} else {
while (!AcquireSpinLockOrFail (SpinLock)) {
CpuPause ();
}
}
return SpinLock;
}
/**
Attempts to place a spin lock in the acquired state.
This function checks the state of the spin lock specified by SpinLock. If
SpinLock is in the released state, then this function places SpinLock in the
acquired state and returns TRUE. Otherwise, FALSE is returned. All state
transitions of SpinLock must be performed using MP safe mechanisms.
If SpinLock is NULL, then ASSERT().
If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
@param SpinLock A pointer to the spin lock to place in the acquired state.
@retval TRUE SpinLock was placed in the acquired state.
@retval FALSE SpinLock could not be acquired.
**/
)
{
return (BOOLEAN)(
) == (VOID*)SPIN_LOCK_RELEASED
);
}
/**
Releases a spin lock.
This function places the spin lock specified by SpinLock in the release state
and returns SpinLock.
If SpinLock is NULL, then ASSERT().
If SpinLock was not initialized with InitializeSpinLock(), then ASSERT().
@param SpinLock A pointer to the spin lock to release.
@return SpinLock released lock.
**/
)
{
return SpinLock;
}
/**
Performs an atomic increment of an 32-bit unsigned integer.
Performs an atomic increment of the 32-bit unsigned integer specified by
Value and returns the incremented value. The increment operation must be
performed using MP safe mechanisms. The state of the return value is not
guaranteed to be MP safe.
If Value is NULL, then ASSERT().
@param Value A pointer to the 32-bit value to increment.
@return The incremented value.
**/
)
{
return InternalSyncIncrement (Value);
}
/**
Performs an atomic decrement of an 32-bit unsigned integer.
Performs an atomic decrement of the 32-bit unsigned integer specified by
Value and returns the decremented value. The decrement operation must be
performed using MP safe mechanisms. The state of the return value is not
guaranteed to be MP safe.
If Value is NULL, then ASSERT().
@param Value A pointer to the 32-bit value to decrement.
@return The decremented value.
**/
)
{
return InternalSyncDecrement (Value);
}
/**
Performs an atomic compare exchange operation on a 32-bit unsigned integer.
Performs an atomic compare exchange operation on the 32-bit unsigned integer
specified by Value. If Value is equal to CompareValue, then Value is set to
ExchangeValue and CompareValue is returned. If Value is not equal to CompareValue,
then Value is returned. The compare exchange operation must be performed using
MP safe mechanisms.
If Value is NULL, then ASSERT().
@param Value A pointer to the 32-bit value for the compare exchange
operation.
@param CompareValue 32-bit value used in compare operation.
@param ExchangeValue 32-bit value used in exchange operation.
@return The original *Value before exchange.
**/
)
{
}
/**
Performs an atomic compare exchange operation on a 64-bit unsigned integer.
Performs an atomic compare exchange operation on the 64-bit unsigned integer specified
by Value. If Value is equal to CompareValue, then Value is set to ExchangeValue and
CompareValue is returned. If Value is not equal to CompareValue, then Value is returned.
The compare exchange operation must be performed using MP safe mechanisms.
If Value is NULL, then ASSERT().
@param Value A pointer to the 64-bit value for the compare exchange
operation.
@param CompareValue 64-bit value used in compare operation.
@param ExchangeValue 64-bit value used in exchange operation.
@return The original *Value before exchange.
**/
)
{
}
/**
Performs an atomic compare exchange operation on a pointer value.
Performs an atomic compare exchange operation on the pointer value specified
by Value. If Value is equal to CompareValue, then Value is set to
ExchangeValue and CompareValue is returned. If Value is not equal to
CompareValue, then Value is returned. The compare exchange operation must be
performed using MP safe mechanisms.
If Value is NULL, then ASSERT().
@param Value A pointer to the pointer value for the compare exchange
operation.
@param CompareValue Pointer value used in compare operation.
@param ExchangeValue Pointer value used in exchange operation.
@return The original *Value before exchange.
**/
VOID *
)
{
SizeOfValue = sizeof (*Value);
switch (SizeOfValue) {
case sizeof (UINT32):
);
case sizeof (UINT64):
);
default:
return NULL;
}
}