Function

OSBitXorAtomic

32-bit logical xor operation, performed atomically with respect to all devices that participate in the coherency architecture of the platform.

Declaration

UInt32 OSBitXorAtomic(UInt32 mask, volatile UInt32 *address);

Parameters

mask

The mask to logically or with the value.

address

The 4-byte aligned address of the value to update atomically.

Return Value

The value before the bitwise operation.

Discussion

This function guarantees atomicity only with main system memory. It is specifically unsuitable for use on noncacheable memory such as that in devices; this function cannot guarantee atomicity, for example, on memory mapped from a PCI device. Additionally, this function incorporates a memory barrier on systems with weakly-ordered memory architectures.

The OSBitXorAtomic function logically xors the bits of the specified mask into the value at the specified address and returns the original value.