cl_khr_local_int32_base_atomics

Optional extensions that implement atomic operations on 32-bit signed and unsigned integers to locations in __local memory.

#pragma OPENCL EXTENSION cl_khr_local_int32_base_atomics : enable

Description

An application that wants to use this extension will need to include the #pragma OPENCL EXTENSION cl_khr_local_int32_base_atomics : enable directive in the OpenCL program source.

The atomic functions supported by the cl_khr_local_int32_base_atomics extension are described in the table below. All of the functions listed in the table are performed in one atomic transaction.

Function Description

int atom_add (__local int *p, int val)

unsigned int atom_add (__local unsigned int *p,
          unsigned int val)

 Read the 32-bit 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.

int atom_sub (__local int *p, int val)

unsigned int atom_sub (__local unsigned int *p,
          unsigned int val)

 Read the 32-bit 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.

int atom_xchg (__local int *p, int val)

unsigned int atom_xchg (__local unsigned int *p,
          unsigned int val)

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

int atom_inc (__local int *p)

unsigned int atom_inc (__local unsigned int *p)

 Read the 32-bit 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.

int atom_dec (__local int *p)

unsigned int atom_dec (__local unsigned int *p)

 Read the 32-bit 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.

int atom_cmpxchg (__local int *p, intint, int val)

unsigned int atom_cmpxchg (__local unsigned int *p, 
          unsigned int cmp, unsigned int val)

 Read the 32-bit 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.

Specification

OpenCL Specification

Also see

EXTENSION

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