On 2009-10-27, Hugh Fisher wrote: > Petter Urkedal and Timothy Miller wrote: > >> (c) Someone else will have to tell us about computed branches. > > > > (Just quoting this as a reminder to the readers.) > > Shader Models 1 through 4, corresponding to DirectX up to version 10 and > OpenGL up to 2.1, don't require computed branches. All flow of control > instructions are to known labels or entry points within the source code. > So for just 3D, there's no need for anything but PC-relative/absolute. > > But it occurs to me that GPUs these days also get used for decompressing > images/video and various kinds of Photoshop style image filtering. Since > this is done on existing hardware I'd assume that they don't *need* > indirect branching, but maybe it would make it easier? Anyone want to > comment? > > DirectX 11, just coming out, has a new general purpose computer shader > API. And there's OpenCL ... Long term, I'd suggest people are going to > want computed branches on their GPUs, so allow for it in the design.
It sounds to me that that we can it for now. I think it has somewhat limited applicability anyway, and one can always do the same in log N time with binary branches, where N is smaller than the address width. _______________________________________________ Open-graphics mailing list [email protected] http://lists.duskglow.com/mailman/listinfo/open-graphics List service provided by Duskglow Consulting, LLC (www.duskglow.com)
