[Mesa-dev] [PATCH 1/2] i965: Assert that math instructions don't have conditional mod.

[Matt Turner]

On Sat, Nov 22, 2014 at 12:50 AM, Kenneth Graunke <kenneth at whitecape.org> wrote:
> On Friday, November 21, 2014 12:41:25 PM Matt Turner wrote:
>> ---
>> Strangely, the suggested implementations of double-precision sqrt/rcp
>> in the BSpec show using a math instruction with an "eo" conditional
>> modifier. I have no idea what that could possibly mean, or how it could
>> work since conditional mod shares the same four bits with math SFID.
>
> I'm confused - what generation of hardware are you talking about?
> The MATH instruction doesn't have an SFID on Gen6+...only Gen4-5, where
> it was a message.  But I wasn't aware double precision was even remotely
> possible on Gen4-5.

Gen6+. I think SFID was the wrong term. The IVB PRM calls it FC in the
instruction machine word table.