[Mesa-dev] [PATCH 28/53] st/nine: Match REP implementation to LOOP

[Ilia Mirkin]

On Wed, Jan 7, 2015 at 11:36 AM, Axel Davy <axel.davy at ens.fr> wrote:
> Previous implementation was fine,
> just instead of having increasing counter,
> have a decreasing counter.
>
> Signed-off-by: Axel Davy <axel.davy at ens.fr>
> ---
>  src/gallium/state_trackers/nine/nine_shader.c | 41 +++++++++++++++------------
>  1 file changed, 23 insertions(+), 18 deletions(-)
>
> diff --git a/src/gallium/state_trackers/nine/nine_shader.c b/src/gallium/state_trackers/nine/nine_shader.c
> index 21b06ce..88d4c07 100644
> --- a/src/gallium/state_trackers/nine/nine_shader.c
> +++ b/src/gallium/state_trackers/nine/nine_shader.c
> @@ -1562,9 +1562,7 @@ 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;
>
>      label = tx_bgnloop(tx);
>      ctr = tx_get_loopctr(tx, FALSE);
> @@ -1572,33 +1570,40 @@ DECL_SPECIAL(REP)
>      /* 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);
> +    ureg_MOV(ureg, ureg_writemask(ctr, NINED3DSP_WRITEMASK_0), rep);
> +    /* in the case ctr is float, remove 0.5 to avoid precision issues for comparisons */
> +    if (!tx->native_integers)
> +        ureg_ADD(ureg, ureg_writemask(ctr, NINED3DSP_WRITEMASK_0), ureg_src(ctr), ureg_imm1f(ureg, -0.5f));
> +
>      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);
> +
> +    /* stop when crt.x <= 0 */

ctr.x

> +    if (!tx->native_integers) {
> +        ureg_SLE(ureg, tmp, ureg_scalar(ureg_src(ctr), TGSI_SWIZZLE_X), ureg_imm1f(ureg, 0.0f));

It would be less confusing if this were the same as below, i.e. switch
it to SGT. Or switch the other one to ISLT. Having one be greater and
one less-than is weird.

>          ureg_IF(ureg, tx_src_scalar(tmp), tx_cond(tx));
> +    } else {
> +        ureg_ISGE(ureg, tmp, ureg_imm1i(ureg, 0), ureg_scalar(ureg_src(ctr), TGSI_SWIZZLE_X));
> +        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);
> +
> +    if (!tx->native_integers) {
> +        ureg_ADD(ureg, ureg_writemask(ctr, NINED3DSP_WRITEMASK_0), ureg_src(ctr), ureg_imm1f(ureg, -1.0f));
> +    } else {
> +        ureg_UADD(ureg, ureg_writemask(ctr, NINED3DSP_WRITEMASK_0), ureg_src(ctr), ureg_imm1i(ureg, -1.0));

-1 -- presumably this is an integer...

But at what point does ctr get converted to an integer? At the
beginning, when you subtract 0.5, it appears to still be a float... I
think that ADD is wrong and needs to be a UADD? (But then obviously
-0.5 doesn't make sense).

> +    }
> +
>      ureg_ENDLOOP(tx->ureg, tx_endloop(tx));
>      return D3D_OK;
>  }
> --
> 2.1.3
>
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