[Mesa-dev] TGSI 16-bit support

[Nicolai Hähnle]

On 24.08.2017 14:19, Erik Faye-Lund wrote:
> On Wed, Aug 23, 2017 at 6:19 PM, Marek Olšák <maraeo at gmail.com> wrote:
>> On Wed, Aug 23, 2017 at 3:08 PM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
>>>
>>> Here's another question: What does "low precision" mean on a texture
>>> instruction? Are the offsets low precision or is it the output? Maybe we can
>>> punt on this for now -- at least GCN doesn't have low precision there
>>> anyway.
>>
>> HalfPrecision means that all dst and src sources can be 16-bit.
>>
>> If the consumer of a TEX instruction is 16-bit, TEX should return
>> 16-bit automatically. If a source of a TEX instruction is 16-bit, TEX
>> should accept 16-bit automatically.
> 
> This sounds inconsistent with how lowp works; a texture-sampler
> declared as lowp in GLSL only have low precision output AFAIK.

lowp and mediump are entirely optional concepts. Their precision can be 
as high as highp operations.

Cheers,
Nicolai
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