[Mesa-dev] [PATCH] radeonsi: implement legacy RCP behavior to fix Unreal engine demos

[Marek Olšák]

It affects all floating-point instructions and it works like an output
modifier. If DX10 doesn't allow it, then I don't know why it's called
"DX10 mode".

Marek

On Wed, Dec 10, 2014 at 9:55 PM, Roland Scheidegger <sroland at vmware.com> wrote:
> Hmm so would that apply to all vector alu ops? Weird (dx10 certainly
> does not generally clamp NaNs to zero).
>
> Roland
>
> Am 10.12.2014 um 21:40 schrieb Marek Olšák:
>> From the SI ISA:
>>
>> "Used by the vector ALU to force DX10-style treatment of NaNs: when
>> set, clamp NaN to zero; otherwise, pass NaN through."
>>
>> Marek
>>
>> On Wed, Dec 10, 2014 at 9:33 PM, Roland Scheidegger <sroland at vmware.com> wrote:
>>> I am curious, how does this bit change the shader (or shader operations,
>>> export, or whatever).
>>> I guess you're referring to the bit saying "Drives dx10 clamp in spi_sq
>>> newWave cmd" settable separately for each shader type but that doesn't
>>> mean much to me :-).
>>>
>>> Roland
>>>
>>> Am 10.12.2014 um 21:16 schrieb Marek Olšák:
>>>> Wow, yes! The DX10_CLAMP bit fixes this issue too. I guess we don't
>>>> have to use legacy instructions now.
>>>>
>>>> Marek
>>>>
>>>> On Mon, Dec 8, 2014 at 5:05 AM, Michel Dänzer <michel at daenzer.net> wrote:
>>>>> On 04.12.2014 21:34, Marek Olšák wrote:
>>>>>> From: Marek Olšák <marek.olsak at amd.com>
>>>>>>
>>>>>> Discussion: https://urldefense.proofpoint.com/v2/url?u=https-3A__bugs.freedesktop.org_show-5Fbug.cgi-3Fid-3D83510-23c8&d=AAIGaQ&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=Vjtt0vs_iqoI31UfJxBl7yv9I2FeiaeAYgMTLKRBc_I&m=wYbokNJOnFBGstvWMmYoGPCVEP9QfPQw0wnRl42Jw0Q&s=rVzVSrX2MYZiMDzqraJyiS53MdcsrSnVfVdG6WQyWOs&e=
>>>>>
>>>>> I wonder if we could avoid at least some of this trouble using the DX10
>>>>> / IEEE bits in the shader MODE register.
>>>>>
>>>>>
>>>>> --
>>>>> Earthling Michel Dänzer               |               https://urldefense.proofpoint.com/v2/url?u=http-3A__www.amd.com_&d=AAIGaQ&c=Sqcl0Ez6M0X8aeM67LKIiDJAXVeAw-YihVMNtXt-uEs&r=Vjtt0vs_iqoI31UfJxBl7yv9I2FeiaeAYgMTLKRBc_I&m=wYbokNJOnFBGstvWMmYoGPCVEP9QfPQw0wnRl42Jw0Q&s=j8yXvz073rSQDrLT-gDX9jMI3wFgZNH4XNK78KVjwF4&e=
>>>>> Libre software enthusiast             |             Mesa and X developer
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>>>>
>>>
>