Maxwell3D: Rework CBData Upload

src/video_core/engines/maxwell_3d.h

@@ -1244,6 +1244,15 @@ private:
 
     Upload::State upload_state;
 
+    static constexpr u32 null_cb_data = 0xFFFFFFFF;
+    struct {
+        std::array<std::array<u32, 0x4000>, 16> buff;
+        u32 current{null_cb_data};
+        u32 id{null_cb_data};
+        u32 start_pos{};
+        u32 counter{};
+    } cb_data_state;
+
     /// Retrieves information about a specific TIC entry from the TIC buffer.
     Texture::TICEntry GetTICEntry(u32 tic_index) const;
 
@@ -1275,7 +1284,9 @@ private:
     void ProcessSyncPoint();
 
     /// Handles a write to the CB_DATA[i] register.
+    void StartCBData(u32 method);
     void ProcessCBData(u32 value);
+    void FinishCBData();
 
     /// Handles a write to the CB_BIND register.
     void ProcessCBBind(Regs::ShaderStage stage);