[Mesa-dev] [PATCH 20/37] i965/gen6/gs: Implement GS_OPCODE_SET_PRIMITIVE_ID.

[Jordan Justen]

On Thu, Aug 14, 2014 at 4:11 AM, Iago Toral Quiroga <itoral at igalia.com> wrote:
> In gen6 the geometry shader payload includes the PrimitiveID information in
> r0.1. When the shader code uses glPimitiveIdIn we will have to move this to
> a separate hardware register where we can map this attribute. This opcode
> takes the selected destination register and moves r0.1 there.
> ---
>  src/mesa/drivers/dri/i965/brw_defines.h          |  8 ++++++++
>  src/mesa/drivers/dri/i965/brw_shader.cpp         |  2 ++
>  src/mesa/drivers/dri/i965/brw_vec4.h             |  1 +
>  src/mesa/drivers/dri/i965/brw_vec4_generator.cpp | 17 +++++++++++++++++
>  4 files changed, 28 insertions(+)
>
> diff --git a/src/mesa/drivers/dri/i965/brw_defines.h b/src/mesa/drivers/dri/i965/brw_defines.h
> index f6bdaeb..b30a095 100644
> --- a/src/mesa/drivers/dri/i965/brw_defines.h
> +++ b/src/mesa/drivers/dri/i965/brw_defines.h
> @@ -1032,6 +1032,14 @@ enum opcode {
>      * - src1 is the number of primitives written.
>      */
>     GS_OPCODE_FF_SYNC,
> +
> +   /**
> +    * Move r0.1 (which holds PrimitiveID information in gen6) to a separate
> +    * register.
> +    *
> +    * - dst is the GRF where PrimitiveID information will be moved.
> +    */
> +   GS_OPCODE_SET_PRIMITIVE_ID,
>  };
>
>  enum brw_urb_write_flags {
> diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
> index b927601..fc3146c 100644
> --- a/src/mesa/drivers/dri/i965/brw_shader.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
> @@ -534,6 +534,8 @@ brw_instruction_name(enum opcode op)
>        return "get_instance_id";
>     case GS_OPCODE_FF_SYNC:
>        return "ff_sync";
> +   case GS_OPCODE_SET_PRIMITIVE_ID:
> +      return "set_primitive_id";
>
>     default:
>        /* Yes, this leaks.  It's in debug code, it should never occur, and if
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h b/src/mesa/drivers/dri/i965/brw_vec4.h
> index ad3a77f..6e0da6d 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4.h
> +++ b/src/mesa/drivers/dri/i965/brw_vec4.h
> @@ -665,6 +665,7 @@ private:
>     void generate_gs_ff_sync(struct brw_reg dst,
>                              struct brw_reg src0,
>                              struct brw_reg src1);
> +   void generate_gs_set_primitive_id(struct brw_reg dst);
>     void generate_oword_dual_block_offsets(struct brw_reg m1,
>                                           struct brw_reg index);
>     void generate_scratch_write(vec4_instruction *inst,
> diff --git a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
> index 2bf2b67..8293f60 100644
> --- a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
> +++ b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
> @@ -694,6 +694,19 @@ vec4_generator::generate_gs_ff_sync(struct brw_reg dst,
>  }
>
>  void
> +vec4_generator::generate_gs_set_primitive_id(struct brw_reg dst)
> +{
> +   /* In gen6, PrimitiveID is delivered in R0.1 of the payload */
> +   struct brw_reg src = brw_vec8_grf(0, 0);
> +   brw_push_insn_state(p);
> +   brw_set_default_mask_control(p, BRW_MASK_DISABLE);
> +   brw_set_default_access_mode(p, BRW_ALIGN_1);
> +   brw_MOV(p, get_element_ud(dst, 0), get_element_ud(src, 1));
> +   brw_set_default_access_mode(p, BRW_ALIGN_16);

The pop below makes this unneeded, right?

18-20
Reviewed-by: Jordan Justen <jordan.l.justen at intel.com>

> +   brw_pop_insn_state(p);
> +}
> +
> +void
>  vec4_generator::generate_oword_dual_block_offsets(struct brw_reg m1,
>                                                    struct brw_reg index)
>  {
> @@ -1283,6 +1296,10 @@ vec4_generator::generate_vec4_instruction(vec4_instruction *instruction,
>        generate_gs_ff_sync(dst, src[0], src[1]);
>        break;
>
> +   case GS_OPCODE_SET_PRIMITIVE_ID:
> +      generate_gs_set_primitive_id(dst);
> +      break;
> +
>     case SHADER_OPCODE_SHADER_TIME_ADD:
>        brw_shader_time_add(p, src[0],
>                            prog_data->base.binding_table.shader_time_start);
> --
> 1.9.1
>
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