EFIAPI
InterlockedCompareExchangePointer (
IN OUT VOID **Value,
IN VOID *CompareValue,
IN VOID *ExchangeValue
)
{
UINT8 SizeOfValue;
SizeOfValue = sizeof (*Value);
switch (SizeOfValue) {
case sizeof (UINT32):
return (VOID*)(UINTN)InterlockedCompareExchange32 (
(UINT32*)Value,
(UINT32)(UINTN)CompareValue,
(UINT32)(UINTN)ExchangeValue
);
case sizeof (UINT64):
return (VOID*)(UINTN)InterlockedCompareExchange64 (
(UINT64*)Value,
(UINT64)(UINTN)CompareValue,
(UINT64)(UINTN)ExchangeValue
);
default:
ASSERT (FALSE);
return NULL;
}
}
/**
Performs an atomic compare exchange operation to lock semaphore.
The compare exchange operation must be performed using
MP safe mechanisms.
@param Sem IN: 32-bit unsigned integer
OUT: -1
@return Original integer
**/
UINT32
LockdownSemaphore (
IN OUT volatile UINT32 *Sem
)
{
UINT32 Value;
do {
Value = *Sem;
} while (InterlockedCompareExchange32 (
(UINT32*)Sem,
Value, (UINT32)-1
) != Value);
return Value;
}
/**
Performs an atomic compare exchange operation to release semaphore.
The compare exchange operation must be performed using
MP safe mechanisms.
@param Sem IN: 32-bit unsigned integer
OUT: original integer + 1
@return Original integer + 1
**/
UINT32
ReleaseSemaphore (
IN OUT volatile UINT32 *Sem
)
{
UINT32 Value;
do {
Value = *Sem;
} while (Value + 1 != 0 &&
InterlockedCompareExchange32 (
(UINT32*)Sem,
Value,
Value + 1
) != Value);
return Value + 1;
}
/**
Performs an atomic compare exchange operation to get semaphore.
The compare exchange operation must be performed using
MP safe mechanisms.
@param Sem IN: 32-bit unsigned integer
OUT: original integer - 1
@return Original integer - 1
**/
UINT32
WaitForSemaphore (
IN OUT volatile UINT32 *Sem
)
{
UINT32 Value;
do {
Value = *Sem;
} while (Value == 0 ||
InterlockedCompareExchange32 (
(UINT32*)Sem,
Value,
Value - 1
) != Value);
return Value - 1;
}