new file mode 100644
--- /dev/null
+++ b/window/system.cc
@@ -0,0 +1,108 @@
+/*
+ * Copyright (c) 2004-2006  Kazunori "jagarl" Ueno
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+ * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+ * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include<SDL.h>
+#include"system.h"
+#include<iostream>
+#include<stdio.h>
+
+using namespace std;
+
+// void SDL_SetEventFilter(SDL_EventFilter filter);
+// typedef int (*SDL_EventFilter)(const SDL_Event *event);
+namespace System {
+
+Main* Main::instance = 0;
+
+int Main::event_filter(const SDL_Event* event) {
+	return 1; /* throw all event */
+}
+
+Main::Main(void) {
+	instance = this;
+	framerate = 20;
+	cursor = 0;
+}
+Main::~Main() {
+	if (cursor) delete cursor;
+}
+void Main::Quit(void) {
+	is_exit = true;
+}
+void Main::EnableVideo(void) {
+	is_video_update = true;
+}
+void Main::DisableVideo(void) {
+	is_video_update = false;
+}
+bool Main::is_exit = false;
+bool Main::is_video_update = true;
+
+void Main::Mainloop(void) {
+	SDL_SetEventFilter(&event_filter);
+	Uint32 old_time = 0;
+	while(!is_exit) {
+		Uint32 start_time = SDL_GetTicks();
+		if (! event.Exec(start_time)) break;
+		if (start_time - old_time > 1000/framerate) {
+			if (is_video_update) root.ExecUpdate();
+			event.Exec(Event::Time::FRAME_UPDATE);
+			cout.flush();
+			old_time = start_time;
+		}
+
+// 問題：
+// z 軸と xy 軸の相互干渉；高速化
+// 移動するウィジット描画の高速化
+// キャッシュ
+// 文字列の一部のみ更新の高速化
+// 「階層 z で x なる領域無効化、y なる領域生成」で良い？＞Expose
+/*
+		Uint32 end_time = SDL_GetTicks();
+		Uint32 delay = (end_time-start_time);
+		if(delay < 1000/framerate) SDL_Delay(1000/framerate - delay);
+		else SDL_Delay(0);
+*/
+		SDL_Delay(0);
+	};
+}
+
+void Main::SetCursor(Surface* s, const Rect& r) {
+	if (instance == 0) return;
+	if (instance->cursor) delete instance->cursor;
+	if (s == 0) { // カーソル消去
+		instance->cursor = 0;
+	} else if (s == DEFAULT_MOUSECURSOR) {
+		instance->cursor = 0;
+		SDL_ShowCursor(SDL_ENABLE);
+	} else {
+		instance->cursor = new WidMouseCursor(instance->event, instance->root.root, s, r.lx, r.ty, r.width(), r.height());
+		instance->cursor->show();
+		SDL_ShowCursor(SDL_DISABLE);
+	}
+}
+}