Microsoft Specific
Loads a 128-bit value atomically.
__int64 __load128(
__int64 volatile * Source,
__int64 *DestinationHigh
);
__int64 __load128_acq(
__int64 volatile * Source,
__int64 *DestinationHigh
);
Parameters
[in] Source
Pointer to the 128-bit source value.[out] DestinationHigh
Pointer to a memory location where the most significant 64-bit quadword of the 128-bit loaded value is stored.
Return Value
The return value is the least significant quadword of the 128-bit loaded value.
Platforms
Function |
Architecture |
|---|---|
__load128 |
IA64 |
__load128_acq |
IA64 |
Requirements
Header file <intrin.h>
Remarks
The __load128 function performs an atomic 128-bit read from the source memory location. The Source pointer should point to a 16-byte aligned memory location.
These functions are not general purpose 128-bit intrinsics. These functions should only be used if you really need 128-bit atomic loads. You get better performance with regular 64-bit operations.
Note that the intrinsic form of this function has a leading underscore in the name. Also note that these functions are always expanded as intrinsics. That means you might use /Oi or #pragma intrinsic, but it is not required.
The __load128_acq intrinsic function is the same as the corresponding function without the _acq suffix except that the operation is performed with acquire semantics.
In Visual C++ 2005, these functions behave as read-write barriers. For more information, see _ReadWriteBarrier.