Is OpenCL not supported on the 3870 cards because compute shader mode is not supported?
Why isn't compute shader mode supported? The SIMD engines on the 3870 are essentially the same as the 4870 and the 5870 correct?
IMHO radeon 3xxx does not have local memory.
http://www.bit-tech.net/hardware/graphics/2008/09/02/ati-radeon-4850-4870-architecture-review/7
The introduction of a 16KB local data share (that's separate from the texture cache) for each SIMD unit allows data to be shared between threads or stream processors, while there's also a global data share that all SIMDs can access, meaning data can be shared right across the GPU.
Is there any plan to suppoirt OpenCL on the 3xxx series chips? They were supported in the 1.4 Stream SDK after all...
OpenCL wont be supported in 3xxx series chips as they don't have the required hardware to execute OpenCL kernels.
Surely you can use LLVM to translate higher level GPU IL code into something the 3xxx series can handle?
Well OpenCL requires that the hardware have some capability to organize threads into groups that execute on a SIMD and that the thread group have some sort of synchronization ability. 38xx series doesnt have that ability that at all. There is no way to say "group these 512 threads together". RV7xx is the first series from AMD to feature the so-called "compute shaders" which allow you to form thread groups. So OpenCL isnt going to come to 38xx series cards.
(Note : not associated with AMD.)