<html> <head> <base href="https://bugs.freedesktop.org/" /> </head> <body> <div> <a class="bz_bug_link bz_status_NEW " title="NEW - Add FP64 support to the i965 shader backends" href="https://bugs.freedesktop.org/show_bug.cgi?id=92760#c1">Comment # 1</a> on <a class="bz_bug_link bz_status_NEW " title="NEW - Add FP64 support to the i965 shader backends" href="https://bugs.freedesktop.org/show_bug.cgi?id=92760">bug 92760</a> from <a class="email" href="mailto:cwabbott0@gmail.com" title="Connor Abbott <cwabbott0@gmail.com>"> Connor Abbott</a> <pre>(In reply to Jason Ekstrand from <a href="show_bug.cgi?id=92760#c0">comment #0</a>) > We've had a variety of people take a crack at this over the last year or two > and haven't actually gotten there yet. I'm making this bug as a place to > put notes for the next person to pick it up. Connor Abbott started on this > towards the end of this summer but there's still more work to do. The best > place to pick up would probably be with his branch which can be found here: > > <a href="http://cgit.freedesktop.org/~cwabbott0/mesa/log/?h=i965-fp64-v2">http://cgit.freedesktop.org/~cwabbott0/mesa/log/?h=i965-fp64-v2</a> > > With this branch, most of the core NIR bits are in place and most of the > i965 fs backend code is in place but there's still more to do: > > 1) Review core NIR bits (Probably Jason) > > 2) Write a bit-width well-definedness validator for nir_algebraic (Probably > Jason or Connor) > > 3) Write piglit tests for and fix up Uniform alignment issues. The > hardware requires that 64-bit things be 64-bit aligned and we're doing > nothing right now to ensure that. > > 4) Implement NIR lowering of ftrunc and use that to implement fround etc. > > 5) Write more tests. Right now, the piglit tests for fp64 basically only > test the math operations. There are many other things that need testing > such as uniform packing, UBOs, SSBOs, pack/unpack operations, and whatever > other interactions need testing. One of the issues Connor ran into was that > the "simplest" tests were doing double-precision operations like sqrt that > were lowered lots of operations and made it very hard to debug simple issues. > > 6) Implement a NIR pass to lower double-precision vec4 operations to vec2 > operations for use in the vec4 backend. I actually have this pass in my branch already. What's missing is support in the vec4 backend for handling something like: dvec2 foo = vec2(bar.x, baz.y); which happens when lowering vec4 operations that "cross" the vec2 boundaries, as in e.g. dvec4 foo = bar + baz.xzyw; > > 7) Get fp64 working in the vec4 backend. The vec4 backend can only work > with doubles as vec2's; hence the splitting pass in (6) I actually got this half-working, besides the above-mentioned issue. I believe there are issues with the exec_mask, unless I'm misunderstanding something, but I don't think there are any tests that actually do anything non-dynamically-uniform, so that's another test that needs to be written. > > There's probably more I've missed here but this is what I remember. QWORD spilling! And some of the changes that came out of the discussion with curro. Other than that, I don't remember anything in particular.</pre> </div> <hr> You are receiving this mail because: <ul> <li>You are the QA Contact for the bug.</li> </ul> </body> </html>