Direct3D has two levels of optional double precision support in shaders: Basic/default and extended. I was wondering, which AMD GPUs support extended double precision under Direct3D?
To answer my question (partially), I have verified that the extended double precision instructions are at least supported on GCN cards. However, it appears (surprisingly) that Trinity/Richland APUs do not support fp64 at all under DirectCompute. I have no idea about 5800 series cards but my guess is they do support all fp64 functionality under DirectCompute.