On Tue, Nov 10, 2015 at 6:44 PM, Eric Anholt <e...@anholt.net> wrote: > Ilia Mirkin <imir...@alum.mit.edu> writes: > >> In nv50, and in the python script that Rob circulated, we do: >> >> bld.mkCmp(OP_SET, CC_GE, TYPE_U32, (s = bld.getSSA()), TYPE_U32, m, b); >> >> Do the same in the nir div lowering pass. This fixes the large-udiv-udiv >> piglit tests on freedreno. > > I assume you meant *-op-div-large-uint-uint.shader_test.
Yes. > > vc4 doesn't have uge yet, but I've got a patch to add it and it does > fix one subtest. What this lowering pass is actually doing has never > really made sense to me, but it works, so: > > Acked-by: Eric Anholt <e...@anholt.net> It's a magical sequence of non-sensical operations which appear to produce the proper result with high probability... what's so confusing about that? :) More seriously, I think there are Newton-Raphson overtones in what it's doing, but I never fully traced it down. It kind of loses me after subtracting 2 from the integer representation of the float bits. _______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
