[Mesa-dev] [PATCH v3 06/10] gallium/docs: add precise instruction modifier

[Roland Scheidegger]

While you're at it, you could also add something to TGSI_OPCODE_MAD
itself, that it can be either fused or unfused, whatever is fastest. But
either way,
Reviewed-by: Roland Scheidegger <sroland at vmware.com


Am 16.06.2017 um 21:08 schrieb Karol Herbst:
> Signed-off-by: Karol Herbst <karolherbst at gmail.com>
> ---
>  src/gallium/docs/source/tgsi.rst | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
> index c65d721dec..76c82b3e88 100644
> --- a/src/gallium/docs/source/tgsi.rst
> +++ b/src/gallium/docs/source/tgsi.rst
> @@ -26,7 +26,13 @@ each of the components of *dst*. When this happens, the result is said to be
>  Modifiers
>  ^^^^^^^^^^^^^^^
>  
> -TGSI supports modifiers on inputs (as well as saturate modifier on instructions).
> +TGSI supports modifiers on inputs (as well as saturate and precise modifier
> +on instructions).
> +
> +For arithmetic instruction having a precise modifier certain optimizations
> +which may alter the result are disallowed. Example: *add(mul(a,b),c)* can't be
> +optimized to TGSI_OPCODE_MAD, because some hardware only supports the fused
> +MAD instruction.
>  
>  For inputs which have a floating point type, both absolute value and
>  negation modifiers are supported (with absolute value being applied
>