Improve SPU code and support state of voice

include/PSX/SPU/spu.hpp

@@ -11,7 +11,7 @@ namespace JabyEngine {
         
         // TODO: Rename to sample...?
         struct Voice {
-            size_t get_id() {
+            size_t get_id() const {
                 return reinterpret_cast<size_t>(this);
             }
 
@@ -33,11 +33,22 @@ namespace JabyEngine {
                 SPU_IO::Key::On.write(SPU_IO::KeyOn::for_specific(Voice::get_id()));
             }
 
+            void play_if_end() {
+                if(Voice::is_end()) {
+                    Voice::play();
+                }
+            }
+
             void stop() {
                 SPU_IO::Key::Off.write(SPU_IO::KeyOff::for_specific(Voice::get_id()));
             }
+
+            bool is_end() const {
+                // TODO: Make work in XEBRA
+                return SPU_IO::Key::Status.read().is_set(Voice::get_id());
+            }
         };
 
-        extern Voice voice[SPU_IO::VoiceCount];
+        static auto& voice = __new_declare_io_port_array(Voice, SPU_IO::VoiceCount, 0x0);
     }
 }