Re: [Mesa-dev] [PATCH 7/8] i965/fs: Optimize gl_FrontFacing calculation on Gen6+.
On Fri, Aug 15, 2014 at 4:43 PM, Matt Turner matts...@gmail.com wrote: On Fri, Aug 15, 2014 at 3:26 PM, Anuj Phogat anuj.pho...@gmail.com wrote: With comment on patch 3 addressed: Patches 1-7 are: Acked-by: Anuj Phogat anuj.pho...@gmail.com Thanks for looking over the patches! Acked-by is used in the kernel by a maintainer to acknowledge the changes to his particular subsystem in a patch that affects many subsystems, or for maintainers to say yeah, looks good to me. We use it in Mesa to say yeah, the idea seems good without really saying that we've reviewed the contents of the patch itself. The kernel docs describe what a Reviewed-by really means here [1], but basically it's that (1) I read the patch, (2) I'm satisfied with the patch, (3) I think the patch is worthwhile, and (4) I'm not making any guarantees. :-) Can I upgrade your Acked-bys to Reviewed-bys? Yes. go ahead. [1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/SubmittingPatches#n498 ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
Re: [Mesa-dev] [PATCH 7/8] i965/fs: Optimize gl_FrontFacing calculation on Gen6+.
On Sun, Aug 10, 2014 at 4:18 PM, Matt Turner matts...@gmail.com wrote:
total instructions in shared programs: 4288650 - 4282838 (-0.14%)
instructions in affected programs: 595018 - 589206 (-0.98%)
---
src/mesa/drivers/dri/i965/brw_fs.cpp | 21 +++--
1 file changed, 15 insertions(+), 6 deletions(-)
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp
b/src/mesa/drivers/dri/i965/brw_fs.cpp
index f394ec9..f7cadd5 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -1188,13 +1188,22 @@
fs_visitor::emit_frontfacing_interpolation(ir_variable *ir)
{
fs_reg *reg = new(this-mem_ctx) fs_reg(this, ir-type);
- /* The frontfacing comes in as a bit in the thread payload. */
if (brw-gen = 6) {
- emit(BRW_OPCODE_SHL, *reg,
- fs_reg(retype(brw_vec1_grf(0, 0), BRW_REGISTER_TYPE_D)),
- fs_reg(16));
- emit(BRW_OPCODE_NOT, *reg, *reg);
- emit(BRW_OPCODE_ASR, *reg, *reg, fs_reg(31));
+ /* Bit 15 of g0.0 is 0 if the polygon is front facing. We want to
create
+ * a boolean result from this (~0/true or 0/false).
+ *
+ * We can use the fact that bit 15 is the MSB of g0.0:W to accomplish
+ * this task in only one instruction:
+ *- a negation source modifier will flip the bit; and
+ *- a W - D type conversion will sign extend the bit into the high
+ * word of the destination.
+ *
+ * An ASR 15 fills the low word of the destination.
+ */
Nice trick.
+ fs_reg g0 = fs_reg(retype(brw_vec1_grf(0, 0), BRW_REGISTER_TYPE_W));
+ g0.negate = true;
+
+ emit(ASR(*reg, g0, fs_reg(15)));
} else {
struct brw_reg r1_6ud = retype(brw_vec1_grf(1, 6),
BRW_REGISTER_TYPE_UD);
/* bit 31 is primitive is back face, so checking (1 31) gives
--
1.8.5.5
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With comment on patch 3 addressed:
Patches 1-7 are: Acked-by: Anuj Phogat anuj.pho...@gmail.com
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Re: [Mesa-dev] [PATCH 7/8] i965/fs: Optimize gl_FrontFacing calculation on Gen6+.
On Fri, Aug 15, 2014 at 3:26 PM, Anuj Phogat anuj.pho...@gmail.com wrote: With comment on patch 3 addressed: Patches 1-7 are: Acked-by: Anuj Phogat anuj.pho...@gmail.com Thanks for looking over the patches! Acked-by is used in the kernel by a maintainer to acknowledge the changes to his particular subsystem in a patch that affects many subsystems, or for maintainers to say yeah, looks good to me. We use it in Mesa to say yeah, the idea seems good without really saying that we've reviewed the contents of the patch itself. The kernel docs describe what a Reviewed-by really means here [1], but basically it's that (1) I read the patch, (2) I'm satisfied with the patch, (3) I think the patch is worthwhile, and (4) I'm not making any guarantees. :-) Can I upgrade your Acked-bys to Reviewed-bys? [1] http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/SubmittingPatches#n498 ___ mesa-dev mailing list mesa-dev@lists.freedesktop.org http://lists.freedesktop.org/mailman/listinfo/mesa-dev
