Optional extensions that implement atomic operations on 64bit signed and unsigned integers to locations in __global and __local memory.
An application that wants to use this extension will need to include the #pragma OPENCL EXTENSION cl_khr_int64_base_atomics : enable
directive in the OpenCL program source.
The atomic functions supported by the cl_khr_int64_base_atomics
extension are described in the following table. All of the functions listed in the following table are performed in one atomic transaction.
These transactions are atomic for the device executing these atomic functions. There is no guarantee of atomicity if the atomic operations to the same memory location are being performed by kernels executing on multiple devices.
Function  Description 

long
long 
Read the 64bit value (referred to as old )
stored at location pointed by p . Compute
(old + val ) and store result at location
pointed by p . The function returns old .

long
long 
Read the 64bit value (referred to as old )
stored at location pointed by p . Compute
(old  val ) and store result at location
pointed by p . The function returns old .

long
long 
Swaps the old value
stored at location p with new value given by
val ). Returns old value.

long
long 
Read the 64bit value (referred to as old )
stored at location pointed by p . Compute
(old + 1) and store result at location
pointed by p . The function returns old .

long
long 
Read the 64bit value (referred to as old )
stored at location pointed by p . Compute
(old  1) and store result at location
pointed by p . The function returns old .

long
long
ulong
ulong 
Read the 64bit value (referred to as old )
stored at location pointed by p . Compute
(old == cmp ) ? val : old and store result at location
pointed by p . The function returns old .
