What the standard would mean is that compute, graphics and digital-signal processors will be able to directly address the same physical RAM in a more cache-coherent manner. It will mean the end of external buses and loosely linked interconnects, and allow data to be processed at the same time.
A GPU and CPU can work on the same bits of memory in an application in a multi-threaded way. The spec refers to GPUs and DSPs as "kernel agents" which sounds a bit like corporate spies for KFC.
The blueprints support 64-bit and 32-bit, and map out virtual memory, memory coherency, and message passing, programming models, and hardware requirements.
While the standard is backed by AMD, ARM, Imagination Technologies, MediaTek, Qualcomm, and Samsung, Intel and Nvidia are giving it a miss. The thought is that with these names onboard there should be a enough of a critical mass of developers who will build HSA-compliant games and tools.
