[Mesa-dev] [PATCH] gm107/ir: fix sign bit emission for FADD32I

[Samuel Pitoiset]

On 07/04/2016 01:59 PM, Ilia Mirkin wrote:
> That flips the sign of the immediate. Why not flip 0x35, which is an
> explicit neg modifier? I guess we mess with the immediate in the other
> emitters, so r-b either way.

Sure, that flips the sign yeah.

I guess we mess up with the neg modifier actually because it is not set 
for that source. I didn't check the other emitters but that test passes 
on GK107 (and probably on GF100/GK110 as well).

>
> As an aside, how did you hit this? Should have gotten folded in...

With piglit. :)

>
>
> On Jul 4, 2016 7:12 AM, "Samuel Pitoiset" <samuel.pitoiset at gmail.com
> <mailto:samuel.pitoiset at gmail.com>> wrote:
>
>     When emitting OP_SUB, the sign bit for FADD and FADD32I is not
>     at the same position. It's at position 45 for FADD but 51 for FADD32I.
>
>     This fixes the following piglit test:
>     tests/spec/arb_fragment_program/fdo30337b.shader_test
>
>     Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com
>     <mailto:samuel.pitoiset at gmail.com>>
>     Cc: <mesa-stable at lists.freedesktop.org
>     <mailto:mesa-stable at lists.freedesktop.org>>
>     ---
>      src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp | 9
>     ++++++---
>      1 file changed, 6 insertions(+), 3 deletions(-)
>
>     diff --git
>     a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
>     b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
>     index 2c5e8f6..f1ba27a 100644
>     --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
>     +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_emit_gm107.cpp
>     @@ -1234,6 +1234,9 @@ CodeEmitterGM107::emitFADD()
>            emitABS(0x2e, insn->src(0));
>            emitNEG(0x2d, insn->src(1));
>            emitFMZ(0x2c, 1);
>     +
>     +      if (insn->op == OP_SUB)
>     +         code[1] ^= 0x00002000;
>         } else {
>            emitInsn(0x08000000);
>            emitABS(0x39, insn->src(1));
>     @@ -1243,10 +1246,10 @@ CodeEmitterGM107::emitFADD()
>            emitNEG(0x35, insn->src(1));
>            emitCC  (0x34);
>            emitIMMD(0x14, 32, insn->src(1));
>     -   }
>
>     -   if (insn->op == OP_SUB)
>     -      code[1] ^= 0x00002000;
>     +      if (insn->op == OP_SUB)
>     +         code[1] ^= 0x00080000;
>     +   }
>
>         emitGPR(0x08, insn->src(0));
>         emitGPR(0x00, insn->def(0));
>     --
>     2.8.0
>
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-- 
-Samuel