I want to openCL pointer compute using global ulong pointer.

My purpose is that one image in host computer is copyed the gpu memory and this image is computed using pointer in openCL(gpu)..
Then I finally obtain from bmp image to encoding data.

But the pointer operation is very difficult to me.
It is not same action with cpu. (it = opencl or gpu)

Give me an advise.. Almost like I'm going crazy..