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

[Axel Davy]

Le 07/01/2015 21:13, Ilia Mirkin a écrit :
On Wed, Jan 7, 2015 at 11:36 AM, Axel Davy <axel.d...@ens.fr> wrote:
Previous implementation was fine,
just instead of having increasing counter,
have a decreasing counter.
Signed-off-by: Axel Davy <axel.d...@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...
Yep, should be -1. Strange compiler didn't warn.

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).
ctr is either an integer from the start, or not.

When the card doesn't support integers, ctr is a float. To avoid 
precision issues when doing comparison to 0, I choosed to substract 0.5 
to ctr.

I realise now it makes more sense to compare ctr to 0.5 and not 
substract anything at the start.

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

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