NAME

       cl_khr_int64_base_atomics - Optional extensions that implement atomic operations on 64-bit
       signed and unsigned integers to locations in __global and __local memory.

       #pragma OPENCL EXTENSION
       cl_khr_int64_base_atomics : enable

DESCRIPTION

       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.

       Atomic operations on 64-bit integers and 32-bit integers (and float) are also atomic
       w.r.t. each other.

       ┌───────────────────┬──────────────────────────────────┐
       │Function           │ Description                      │
       ├───────────────────┼──────────────────────────────────┤
       │atom_add(3clc)     │ Compute (old + val)              │
       ├───────────────────┼──────────────────────────────────┤
       │atom_sub(3clc)     │ Compute (old - val)              │
       ├───────────────────┼──────────────────────────────────┤
       │atom_xchg(3clc)    │ Swaps the 32-bit value (old)     │
       │                   │ stored at location p with new    │
       │                   │ value val.                       │
       ├───────────────────┼──────────────────────────────────┤
       │atom_inc(3clc)     │ Compute (old + 1)                │
       ├───────────────────┼──────────────────────────────────┤
       │atom_dec(3clc)     │ Compute (old - 1)                │
       ├───────────────────┼──────────────────────────────────┤
       │atom_cmpxchg(3clc) │ Compute (old == cmp) ? val : old │
       └───────────────────┴──────────────────────────────────┘

SPECIFICATION

       OpenCL Specification[1]

SEE ALSO

       EXTENSION(3clc), cl_khr_int64_extended_atomics(3clc), atomicFunctions(3clc)

AUTHORS

       The Khronos Group

COPYRIGHT

       Copyright © 2007-2011 The Khronos Group Inc.
       Permission is hereby granted, free of charge, to any person obtaining a copy of this
       software and/or associated documentation files (the "Materials"), to deal in the Materials
       without restriction, including without limitation the rights to use, copy, modify, merge,
       publish, distribute, sublicense, and/or sell copies of the Materials, and to permit
       persons to whom the Materials are furnished to do so, subject to the condition that this
       copyright notice and permission notice shall be included in all copies or substantial
       portions of the Materials.

NOTES

        1. OpenCL Specification
           page 10, section 9.3 - 64-bit Atomics