[Mesa-dev] [PATCH 01/12] i965/fs: Define logical framebuffer write opcode.

[Francisco Jerez]

The logical variant is largely equivalent to the original opcode but
instead of taking a single payload source it expects the arguments
that make up the payload separately as individual sources, like:

 fb_write_logical null, color0, color1, src0_alpha,
                        src_depth, dst_depth, sample_mask, num_components

This patch defines the opcode and usual instruction boilerplate,
including a placeholder lowering function provided mostly as
self-documentation of its source registers.
---
 src/mesa/drivers/dri/i965/brw_defines.h  |  1 +
 src/mesa/drivers/dri/i965/brw_fs.cpp     | 34 ++++++++++++++++++++++++++++++++
 src/mesa/drivers/dri/i965/brw_fs.h       |  2 +-
 src/mesa/drivers/dri/i965/brw_shader.cpp |  2 ++
 4 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/src/mesa/drivers/dri/i965/brw_defines.h b/src/mesa/drivers/dri/i965/brw_defines.h
index 5bf53e3..65685a9 100644
--- a/src/mesa/drivers/dri/i965/brw_defines.h
+++ b/src/mesa/drivers/dri/i965/brw_defines.h
@@ -875,6 +875,7 @@ enum opcode {
     * instructions.
     */
    FS_OPCODE_FB_WRITE = 128,
+   FS_OPCODE_FB_WRITE_LOGICAL,
    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 eeb6938..ae050b7 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs.cpp
@@ -701,6 +701,13 @@ fs_inst::regs_read(int arg) const
          return 1;
       break;
 
+   case FS_OPCODE_FB_WRITE_LOGICAL:
+      assert(src[6].file == IMM);
+      /* First/second FB write color. */
+      if (arg < 2)
+         components = src[6].fixed_hw_reg.dw1.ud;
+      break;
+
    default:
       if (is_tex() && arg == 0 && src[0].file == GRF)
          return mlen;
@@ -3180,6 +3187,25 @@ fs_visitor::lower_integer_multiplication()
    return progress;
 }
 
+static void
+lower_fb_write_logical_send(const fs_builder &bld, fs_inst *inst,
+                            const brw_wm_prog_data *prog_data,
+                            const brw_wm_prog_key *key,
+                            const fs_visitor::thread_payload &payload)
+{
+   assert(inst->src[6].file == IMM);
+   const brw_device_info *devinfo = bld.shader->devinfo;
+   const fs_reg &color0 = inst->src[0];
+   const fs_reg &color1 = inst->src[1];
+   const fs_reg &src0_alpha = inst->src[2];
+   const fs_reg &src_depth = inst->src[3];
+   const fs_reg &dst_depth = inst->src[4];
+   fs_reg sample_mask = inst->src[5];
+   const unsigned components = inst->src[6].fixed_hw_reg.dw1.ud;
+
+   assert(!"Not implemented");
+}
+
 bool
 fs_visitor::lower_logical_sends()
 {
@@ -3191,6 +3217,14 @@ fs_visitor::lower_logical_sends()
                                  .at(block, inst);
 
       switch (inst->opcode) {
+      case FS_OPCODE_FB_WRITE_LOGICAL:
+         assert(stage == MESA_SHADER_FRAGMENT);
+         lower_fb_write_logical_send(ibld, inst,
+                                     (const brw_wm_prog_data *)prog_data,
+                                     (const brw_wm_prog_key *)key,
+                                     payload);
+         break;
+
       default:
          continue;
       }
diff --git a/src/mesa/drivers/dri/i965/brw_fs.h b/src/mesa/drivers/dri/i965/brw_fs.h
index 9582648..3533d38 100644
--- a/src/mesa/drivers/dri/i965/brw_fs.h
+++ b/src/mesa/drivers/dri/i965/brw_fs.h
@@ -387,7 +387,7 @@ public:
    fs_reg result;
 
    /** Register numbers for thread payload fields. */
-   struct {
+   struct thread_payload {
       uint8_t source_depth_reg;
       uint8_t source_w_reg;
       uint8_t aa_dest_stencil_reg;
diff --git a/src/mesa/drivers/dri/i965/brw_shader.cpp b/src/mesa/drivers/dri/i965/brw_shader.cpp
index d66baf3..44681e4 100644
--- a/src/mesa/drivers/dri/i965/brw_shader.cpp
+++ b/src/mesa/drivers/dri/i965/brw_shader.cpp
@@ -533,6 +533,8 @@ brw_instruction_name(enum opcode op)
       return opcode_descs[op].name;
    case FS_OPCODE_FB_WRITE:
       return "fb_write";
+   case FS_OPCODE_FB_WRITE_LOGICAL:
+      return "fb_write_logical";
    case FS_OPCODE_BLORP_FB_WRITE:
       return "blorp_fb_write";
    case FS_OPCODE_REP_FB_WRITE:
-- 
2.4.3