[Mesa-dev] [PATCH 1/2] r600g: use ieee variants of multiplication instructions

[Ilia Mirkin]

On Tue, Jan 24, 2017 at 1:11 PM, Matteo Bruni <matteo.mystral at gmail.com> wrote:
> 2017-01-24 3:18 GMT+01:00 Ilia Mirkin <imirkin at alum.mit.edu>:
>> This matches the behavior of most other drivers, including nouveau.
>
> Doesn't this break all the applications depending on d3d9 NaN behavior
> (including, but not limited to, d3d9 games in Wine) on r600g?
>
> If I got this right, flipping around the two patches in this series
> and enabling the TGSI_PROPERTY_MUL_ZERO_WINS flag for OpenGL
> non-compute shaders (if that's not the case already) should avoid
> regressions.

This patch normalizes r600g wrt multiply handling with the other
DX10/11 hardware drivers. nv50, nvc0, si, and i965 all use the IEEE
behavior. I don't know for sure, but assume that nv30 and r300 have
the DX9 behavior natively without IEEE support.

The next patch allows for the MUL_ZERO_WINS property to be used to get
the DX9 behavior, which st/nine will make use of.

Cheers,

  -ilia