Global Pointer - Bitwise operation


Hi There,

Is it possible to perform a bitwise xor, and, or on a __global uint * pointer in OpenCL? I’m trying to do this but compiler throws me an error.
The goal is to perform something like:
__global uint *p = an address on global memory
*p = some value
*(p ^ 1) = other value

In C we can manipulate pointers freely - can it be done on OpenCL?

Thanks in advance.


Why not share the error the compiler threw? It would be helpful. Was it that “1” isn’t the same type as “p”? If so, perhaps *(p ^ (__global uint *)1) would work. If not, try casting the pointer to an unsigned integer of the same width, then doing your bitops there, and then casting back.


Hi There,

I have tried what you proposed - something like:
__global uint *p1 = p2 ^ (__global uint *)1 (where p2 is a valid __global uint *)
however compiler throws: "invalid operands to binary expression (’__global uint *’ and ‘__global uint *’)


Seems like you’ll need to use the cast to int, do xor, cast to ptr route.


OK - casting to ulong - then XORing - then cast to __global uint * - worked like a charm. Thanks.

__global uint *p1 = (__global uint *)((ulong)p2 ^ 1);