Improve thread code

src/Library/internal-include/System/callbacks_internal.hpp

@@ -1,12 +1,15 @@
 #pragma once
-#include <PSX/System/threads.hpp>
+#include "threads.hpp"
 
 namespace JabyEngine {
     namespace Callback {
         namespace internal {
-            static void execute_thread(SysCall::ThreadHandle thread_handle) {
-                MainThread::prepare_if_main(thread_handle);
-                Thread::execute_next();    
+            static void execute_callback(Thread::Handle thread_handle) {
+                if(CurrentThread::is_me(MainThread::Handle)) {
+                    CurrentThread::replace_with(thread_handle);
+                }
+
+                SysCall::ReturnFromException();
             }
 
             namespace VSync {
@@ -17,7 +20,7 @@ namespace JabyEngine {
                 void                         routine();
 
                 static void [[deprecated("Currently not in use")]] execute() {
-                    execute_thread(VSync::thread_handle);
+                    execute_callback(VSync::thread_handle);
                 }
             }
 
@@ -28,7 +31,7 @@ namespace JabyEngine {
                 extern uint32_t              stack[StackSize];
 
                 static void execute() {
-                    execute_thread(CD::thread_handle);
+                    execute_callback(CD::thread_handle);
                 }
             }
         }