[Mesa-dev] [PATCH 2/2] gallium: Desambiguate TGSI_OPCODE_IF.

[Marek Olšák]

The R600 code looks good.

Marek


On Sun, Apr 14, 2013 at 10:12 AM, <jfonseca at vmware.com> wrote:

> From: José Fonseca <jfonseca at vmware.com>
>
> TGSI_OPCODE_IF condition had two possible interpretations:
>
> - src.x != 0.0f
>
>   - Mesa statetracker when PIPE_SHADER_CAP_INTEGERS was false either for
>     vertex and fragment shaders
>   - gallivm/llvmpipe
>   - postprocess
>   - vl state tracker
>   - vega state tracker
>   - most old drivers
>   - old internal state trackers
>   - many graw examples
>
> - src.x != 0U
>
>   - Mesa statetracker when PIPE_SHADER_CAP_INTEGERS was true for both
>     vertex and fragment shaders
>   - tgsi_exec/softpipe
>   - r600
>   - radeonsi
>   - nv50
>
> And drivers that use draw module also were a mess (because Mesa would
> emit float IFs, but draw module supports native integers so it would
> interpret IF arg as integers...)
>
> This sort of works if the source argument is limited to float +0.0f or
> +1.0f, integer 0, but would fail if source is float -0.0f, or integer in
> the float NaN range.  It could also fail if source is integer 1, and
> hardware flushes denormalized numbers to zero.
>
> But with this change there are now two opcodes, IF and UIF, with clear
> meaning.
>
> Drivers that do not support native integers do not need to worry about
> UIF.  However, for backwards compatibility with old state trackers and
> examples, it is advisable that native integer capable drivers also
> support the float IF opcode.
>
> I tried to implement this for r600 and radeonsi based on the surrounding
> code.  I couldn't do this for nouveau, so I just shunted IF/UIF
> together, which matches the current behavior.
> ---
>  src/gallium/auxiliary/gallivm/lp_bld_tgsi_action.c |    1 +
>  src/gallium/auxiliary/gallivm/lp_bld_tgsi_aos.c    |    1 +
>  src/gallium/auxiliary/gallivm/lp_bld_tgsi_info.c   |    1 +
>  src/gallium/auxiliary/gallivm/lp_bld_tgsi_soa.c    |   19 ++++++++-
>  src/gallium/auxiliary/tgsi/tgsi_dump.c             |    2 +
>  src/gallium/auxiliary/tgsi/tgsi_exec.c             |   22 +++++++++++
>  src/gallium/auxiliary/tgsi/tgsi_info.c             |    2 +-
>  src/gallium/auxiliary/tgsi/tgsi_opcode_tmp.h       |    1 +
>  src/gallium/docs/source/tgsi.rst                   |   21 ++++++++--
>  .../drivers/nv50/codegen/nv50_ir_from_tgsi.cpp     |    6 +++
>  src/gallium/drivers/r600/r600_shader.c             |   21 +++++++---
>  .../drivers/radeon/radeon_setup_tgsi_llvm.c        |   41
> ++++++++++++++++----
>  src/gallium/include/pipe/p_shader_tokens.h         |    2 +-
>  src/mesa/state_tracker/st_glsl_to_tgsi.cpp         |    8 +++-
>  src/mesa/state_tracker/st_mesa_to_tgsi.c           |   12 +++++-
>  15 files changed, 137 insertions(+), 23 deletions(-)
>
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