[Mesa-dev] [PATCH 04/11] i965/fs: Fix discard and alpha test in 16-wide.

[Kenneth Graunke]

On 05/12/2011 09:05 PM, Eric Anholt wrote:
> As of gen6, alt-mode (which we use) MOVs of floats are not raw --
> they'll modify infs/nans.

This is good to know - I wasn't aware of that.  I'd been assuming that 
any type was as good as any other.  Apparently not...thanks.

> This broke discard and alpha test in
> 16-wide, where apparently the upper 8 bits of the pixel enables being
> set were causing the whole value to get trashed upon being moved.
> Treating the values as UD instead of float makes sure they get
> preserved.  While I'm here, replace the two 8-wide moves of the halves
> of the header with a single compressed move.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=36648

Using UD for loading headers seems quite sensible.  And using a 
compressed MOV makes a lot more sense.

Reviewed-by: Kenneth Graunke <kenneth at whitecape.org>