Gen6 geometry shaders need to allocate URB handles for each new vertex they
emit after the first (the URB handle for the first vertex is obtained via the
FF_SYNC message).
This opcode adds the URB allocation mechanism to regular URB writes.
---
src/mesa/drivers/dri/i965/brw_defines.h | 8 +++++++
src/mesa/drivers/dri/i965/brw_shader.cpp | 2 ++
src/mesa/drivers/dri/i965/brw_vec4.cpp | 1 +
src/mesa/drivers/dri/i965/brw_vec4.h | 1 +
src/mesa/drivers/dri/i965/brw_vec4_generator.cpp | 30 ++++++++++++++++++++++++
5 files changed, 42 insertions(+)
diff --git a/src/mesa/drivers/dri/i965/brw_defines.h
b/src/mesa/drivers/dri/i965/brw_defines.h
index 125d728..60b3846 100644
--- a/src/mesa/drivers/dri/i965/brw_defines.h
+++ b/src/mesa/drivers/dri/i965/brw_defines.h
@@ -929,6 +929,14 @@ enum opcode {
GS_OPCODE_URB_WRITE,
/**
+ * Write geometry shader output data to the URB and request a new URB
+ * handle (gen6).
+ *
+ * This opcode doesn't do an implied move from R0 to the first MRF.
+ */
+ GS_OPCODE_URB_WRITE_ALLOCATE,
+
+ /**
* Terminate the geometry shader thread by doing an empty URB write.
*
* This opcode doesn't do an implied move from R0 to the first MRF. This
diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp
b/src/mesa/drivers/dri/i965/brw_shader.cpp
index 5749061..69d16a7 100644
--- a/src/mesa/drivers/dri/i965/brw_shader.cpp
+++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
@@ -514,6 +514,8 @@ brw_instruction_name(enum opcode op)
case GS_OPCODE_URB_WRITE:
return "gs_urb_write";
+ case GS_OPCODE_URB_WRITE_ALLOCATE:
+ return "gs_urb_write_allocate";
case GS_OPCODE_THREAD_END:
return "gs_thread_end";
case GS_OPCODE_SET_WRITE_OFFSET:
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.cpp
b/src/mesa/drivers/dri/i965/brw_vec4.cpp
index b572b61..e413a05 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4.cpp
@@ -274,6 +274,7 @@ vec4_visitor::implied_mrf_writes(vec4_instruction *inst)
case SHADER_OPCODE_GEN4_SCRATCH_WRITE:
return 3;
case GS_OPCODE_URB_WRITE:
+ case GS_OPCODE_URB_WRITE_ALLOCATE:
case GS_OPCODE_THREAD_END:
return 0;
case SHADER_OPCODE_SHADER_TIME_ADD:
diff --git a/src/mesa/drivers/dri/i965/brw_vec4.h
b/src/mesa/drivers/dri/i965/brw_vec4.h
index 72fabdd..c1daf54 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4.h
+++ b/src/mesa/drivers/dri/i965/brw_vec4.h
@@ -649,6 +649,7 @@ private:
void generate_vs_urb_write(vec4_instruction *inst);
void generate_gs_urb_write(vec4_instruction *inst);
+ void generate_gs_urb_write_allocate(vec4_instruction *inst);
void generate_gs_thread_end(vec4_instruction *inst);
void generate_gs_set_write_offset(struct brw_reg dst,
struct brw_reg src0,
diff --git a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
index 05f4892..8ef0c34 100644
--- a/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
+++ b/src/mesa/drivers/dri/i965/brw_vec4_generator.cpp
@@ -429,6 +429,32 @@ vec4_generator::generate_gs_urb_write(vec4_instruction
*inst)
}
void
+vec4_generator::generate_gs_urb_write_allocate(vec4_instruction *inst)
+{
+ struct brw_reg src = brw_message_reg(inst->base_mrf);
+
+ /* We pass the temporary passed in src0 as the writeback register */
+ brw_urb_WRITE(p,
+ inst->get_src(this->prog_data, 0), /* dest */
+ inst->base_mrf, /* starting mrf reg nr */
+ src,
+ BRW_URB_WRITE_ALLOCATE_COMPLETE,
+ inst->mlen,
+ 1, /* response len */
+ inst->offset, /* urb destination offset */
+ BRW_URB_SWIZZLE_INTERLEAVE);
+
+ /* Now put allocated urb handle in dst.0 */
+ brw_push_insn_state(p);
+ brw_set_default_access_mode(p, BRW_ALIGN_1);
+ brw_set_default_mask_control(p, BRW_MASK_DISABLE);
+ brw_MOV(p, get_element_ud(inst->get_dst(), 0),
+ get_element_ud(inst->get_src(this->prog_data, 0), 0));
+ brw_set_default_access_mode(p, BRW_ALIGN_16);
+ brw_pop_insn_state(p);
+}
+
+void
vec4_generator::generate_gs_thread_end(vec4_instruction *inst)
{
struct brw_reg src = brw_message_reg(inst->base_mrf);
@@ -1206,6 +1232,10 @@
vec4_generator::generate_vec4_instruction(vec4_instruction *instruction,
generate_gs_urb_write(inst);
break;
+ case GS_OPCODE_URB_WRITE_ALLOCATE:
+ generate_gs_urb_write_allocate(inst);
+ break;
+
case GS_OPCODE_THREAD_END:
generate_gs_thread_end(inst);
break;
--
1.9.1
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