[Mesa-dev] [PATCH v2 28/52] st/nine: Match REP implementation to LOOP

[Ilia Mirkin]

Is there a "continue" in d3d9? I couldn't find one, but if there is,
then this change won't work.

On Sat, Jan 10, 2015 at 5:42 AM, Axel Davy <axel.davy at ens.fr> wrote:
> Previous implementation was fine,
> just instead of having increasing counter,
> have a decreasing counter.

Didn't you have some other reason to do this? Why are there all these
changes which are basically just like "Well, I was debugging some bug,
made a bunch of changes, but they ended up making no difference. The
new code has _no_ benefits at all that I can think of, but let's push
them anyways, since code churn is fun."?

Look, I'm sure there's _some_ sort of reason for this stuff, but you
just have to explain it in the commit logs.

>
> Signed-off-by: Axel Davy <axel.davy at ens.fr>
> ---
>  src/gallium/state_trackers/nine/nine_shader.c | 49 ++++++++++++++++-----------
>  1 file changed, 30 insertions(+), 19 deletions(-)
>
> diff --git a/src/gallium/state_trackers/nine/nine_shader.c b/src/gallium/state_trackers/nine/nine_shader.c
> index 9e708c6..0ced8f8 100644
> --- a/src/gallium/state_trackers/nine/nine_shader.c
> +++ b/src/gallium/state_trackers/nine/nine_shader.c
> @@ -1571,43 +1571,54 @@ DECL_SPECIAL(REP)
>      unsigned *label;
>      struct ureg_src rep = tx_src_param(tx, &tx->insn.src[0]);
>      struct ureg_dst ctr;
> -    struct ureg_dst tmp = tx_scratch_scalar(tx);
> -    struct ureg_src imm =
> -        tx->native_integers ? ureg_imm1u(ureg, 0) : ureg_imm1f(ureg, 0.0f);
> +    struct ureg_dst tmp;
> +    struct ureg_src ctrx;
>
>      label = tx_bgnloop(tx);
> -    ctr = tx_get_loopctr(tx, FALSE);
> +    ctr = ureg_writemask(tx_get_loopctr(tx, FALSE), NINED3DSP_WRITEMASK_0);
> +    ctrx = ureg_scalar(ureg_src(ctr), TGSI_SWIZZLE_X);
>
>      /* NOTE: rep must be constant, so we don't have to save the count */
>      assert(rep.File == TGSI_FILE_CONSTANT || rep.File == TGSI_FILE_IMMEDIATE);
>
> -    ureg_MOV(ureg, ctr, imm);
> +    /* rep: num_iterations - 0 - 0 - 0 */
> +    ureg_MOV(ureg, ctr, rep);
>      ureg_BGNLOOP(ureg, label);
> -    if (tx->native_integers)
> -    {
> -        ureg_USGE(ureg, tmp, tx_src_scalar(ctr), rep);
> -        ureg_UIF(ureg, tx_src_scalar(tmp), tx_cond(tx));
> -    }
> -    else
> -    {
> -        ureg_SGE(ureg, tmp, tx_src_scalar(ctr), rep);
> +    tmp = tx_scratch_scalar(tx);
> +    /* Initially ctr.x contains the number of iterations.
> +     * We decrease ctr.x at the end of every iteration,
> +     * and stop when it reaches 0. */
> +
> +    if (!tx->native_integers) {
> +        /* case src and ctr contain floats */
> +        /* to avoid precision issue, we stop when ctr <= 0.5 */
> +        ureg_SGE(ureg, tmp, ureg_imm1f(ureg, 0.5f), ctrx);
>          ureg_IF(ureg, tx_src_scalar(tmp), tx_cond(tx));
> +    } else {
> +        /* case src and ctr contain integers */
> +        ureg_ISGE(ureg, tmp, ureg_imm1i(ureg, 0), ctrx);
> +        ureg_UIF(ureg, tx_src_scalar(tmp), tx_cond(tx));
>      }
>      ureg_BRK(ureg);
>      tx_endcond(tx);
>      ureg_ENDIF(ureg);
>
> -    if (tx->native_integers) {
> -        ureg_UADD(ureg, ctr, tx_src_scalar(ctr), ureg_imm1u(ureg, 1));
> -    } else {
> -        ureg_ADD(ureg, ctr, tx_src_scalar(ctr), ureg_imm1f(ureg, 1.0f));
> -    }
> -
>      return D3D_OK;
>  }
>
>  DECL_SPECIAL(ENDREP)
>  {
> +    struct ureg_program *ureg = tx->ureg;
> +    struct ureg_dst ctr = tx_get_loopctr(tx, FALSE);
> +    struct ureg_dst dst_ctrx = ureg_writemask(ctr, NINED3DSP_WRITEMASK_0);
> +    struct ureg_src src_ctr = ureg_src(ctr);
> +
> +    /* ctr.x -= 1 */
> +    if (!tx->native_integers)
> +        ureg_ADD(ureg, dst_ctrx, src_ctr, ureg_imm1f(ureg, -1.0f));
> +    else
> +        ureg_UADD(ureg, dst_ctrx, src_ctr, ureg_imm1i(ureg, -1));
> +
>      ureg_ENDLOOP(tx->ureg, tx_endloop(tx));
>      return D3D_OK;
>  }
> --
> 2.1.0
>
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