I am new to Renderscript, but not parallel processing.
I am attempting to do an AES ECB design using render script in Android 4.4. I am struggling with the best way to pass to the renderscript root function the necessary preallocated memory structures, SBOX, input stream, output stream, expanded key. My goal is get the execution to occur on the GPU if available.
I have read up on using an allocated array to hold indexes each thread to should accessing(In Android's Renderscript, using the rs_script_call structure to restrict the range of the allocation that is operated upon during a rsForEach call), but even with that I believe I will need three other pointers to the *input stream, *output stream, and the expanded key, plus the sbox.
Is it possible to copy an allocated array into a temp variable in a render script without causing the execution to be tied to the cpu? can I use the X, Y parameters in a thread-id, work-id? Am I missing something else?
x, y do work like thread-id in other compute languages. You should be using global variables for any other necessary input structures (like sboxes, expanded key, etc.). The whole point of RS is to not focus on CPU vs. GPU. The device will take care of things in the most appropriate manner. Trying to force something onto the GPU may result in lower performance, as GPUs might be busy for doing actual graphics work too.