[Mesa-dev] [PATCH 5/6] Implement the proper packing for the stencil payload
Ben Widawsky
benjamin.widawsky at intel.com
Tue Oct 20 14:29:40 PDT 2015
This patch is split out for review. It will be squashed before pushing.
---
src/mesa/drivers/dri/i965/brw_defines.h | 1 +
src/mesa/drivers/dri/i965/brw_fs.cpp | 6 +++-
src/mesa/drivers/dri/i965/brw_fs.h | 2 ++
src/mesa/drivers/dri/i965/brw_fs_generator.cpp | 44 ++++++++++++++++++++++++++
src/mesa/drivers/dri/i965/brw_shader.cpp | 2 ++
5 files changed, 54 insertions(+), 1 deletion(-)
diff --git a/src/mesa/drivers/dri/i965/brw_defines.h b/src/mesa/drivers/dri/i965/brw_defines.h
index c67728b..2c5cd7a 100644
--- a/src/mesa/drivers/dri/i965/brw_defines.h
+++ b/src/mesa/drivers/dri/i965/brw_defines.h
@@ -915,6 +915,7 @@ enum opcode {
*/
FS_OPCODE_FB_WRITE_LOGICAL,
+ FS_OPCODE_PACK_STENCIL_REF,
FS_OPCODE_BLORP_FB_WRITE,
FS_OPCODE_REP_FB_WRITE,
SHADER_OPCODE_RCP,
diff --git a/src/mesa/drivers/dri/i965/brw_fs.cpp b/src/mesa/drivers/dri/i965/brw_fs.cpp
index 560eb91..c962043 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -3440,7 +3440,11 @@ lower_fb_write_logical_send(const fs_builder &bld, fs_inst *inst,
if (src_stencil.file != BAD_FILE) {
assert(devinfo->gen >= 9);
assert(bld.dispatch_width() != 16);
- sources[length] = src_stencil;
+
+ sources[length] = bld.vgrf(BRW_REGISTER_TYPE_UD);
+ bld.exec_all().annotate("FB write OS")
+ .emit(FS_OPCODE_PACK_STENCIL_REF, sources[length],
+ retype(src_stencil, BRW_REGISTER_TYPE_UB));
length++;
}
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 4f59d4b..e2bc469 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -419,6 +419,8 @@ private:
void generate_fb_write(fs_inst *inst, struct brw_reg payload);
void generate_urb_write(fs_inst *inst, struct brw_reg payload);
void generate_cs_terminate(fs_inst *inst, struct brw_reg payload);
+ void generate_stencil_ref_packing(fs_inst *inst, struct brw_reg dst,
+ struct brw_reg src);
void generate_barrier(fs_inst *inst, struct brw_reg src);
void generate_blorp_fb_write(fs_inst *inst);
void generate_linterp(fs_inst *inst, struct brw_reg dst,
diff --git a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
index 1a893c9..80cc6ad 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_generator.cpp
@@ -415,6 +415,46 @@ fs_generator::generate_cs_terminate(fs_inst *inst, struct brw_reg payload)
}
void
+fs_generator::generate_stencil_ref_packing(fs_inst *inst,
+ struct brw_reg dst,
+ struct brw_reg src)
+{
+ assert(dispatch_width == 8);
+ assert(devinfo->gen >= 9);
+
+ /* Stencil value updates are provided in 8 slots of 1 byte per slot.
+ * Presumably, in order to save memory bandwidth, the stencil reference
+ * values written from the FS need to be packed into 2 dwords (this makes
+ * sense because the stencil values are limited to 1 byte each and a SIMD8
+ * send, so stencil slots 0-3 in dw0, and 4-7 in dw1.)
+ *
+ * The spec is confusing here because in the payload definition of MDP_RTW_S8
+ * (Message Data Payload for Render Target Writes with Stencil 8b) the
+ * stencil value seems to be dw4.0-dw4.7. However, if you look at the type of
+ * dw4 it is type MDPR_STENCIL (Message Data Payload Register) which is the
+ * packed values specified above and diagrammed below:
+ *
+ * 31 0
+ * --------------------------------
+ * DW | |
+ * 2-7 | IGNORED |
+ * | |
+ * --------------------------------
+ * DW1 | STC | STC | STC | STC |
+ * | slot7 | slot6 | slot5 | slot4|
+ * --------------------------------
+ * DW0 | STC | STC | STC | STC |
+ * | slot3 | slot2 | slot1 | slot0|
+ * --------------------------------
+ */
+
+ src.width = BRW_WIDTH_1;
+ src.hstride = BRW_HORIZONTAL_STRIDE_0;
+ src.vstride = BRW_VERTICAL_STRIDE_4;
+ brw_MOV(p, retype(dst, BRW_REGISTER_TYPE_UB), retype(src, BRW_REGISTER_TYPE_UB));
+}
+
+void
fs_generator::generate_barrier(fs_inst *inst, struct brw_reg src)
{
brw_barrier(p, src);
@@ -2153,6 +2193,10 @@ fs_generator::generate_code(const cfg_t *cfg, int dispatch_width)
generate_barrier(inst, src[0]);
break;
+ case FS_OPCODE_PACK_STENCIL_REF:
+ generate_stencil_ref_packing(inst, dst, src[0]);
+ break;
+
default:
unreachable("Unsupported opcode");
diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
index 2324b56..c38e34e 100644
--- a/src/mesa/drivers/dri/i965/brw_shader.cpp
+++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
@@ -290,6 +290,8 @@ brw_instruction_name(enum opcode op)
return "fb_write";
case FS_OPCODE_FB_WRITE_LOGICAL:
return "fb_write_logical";
+ case FS_OPCODE_PACK_STENCIL_REF:
+ return "fb write output stencil";
case FS_OPCODE_BLORP_FB_WRITE:
return "blorp_fb_write";
case FS_OPCODE_REP_FB_WRITE:
--
2.6.1
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