--- nono/vm/sysport.h	2026/04/29 17:04:32	1.1.1.2
+++ nono/vm/sysport.h	2026/04/29 17:04:36	1.1.1.3
@@ -1,6 +1,7 @@
 //
 // nono
-// Copyright (C) 2017 isaki@NetBSD.org
+// Copyright (C) 2020 nono project
+// Licensed under nono-license.txt
 //
 
 #pragma once
@@ -26,23 +27,21 @@ struct SYSPORT
 class SysportDevice
 	: public IODevice
 {
-	typedef IODevice inherited;
+	using inherited = IODevice;
  private:
 	static const uint32 baseaddr = 0xe8e000;
 
  public:
 	SysportDevice();
-	virtual ~SysportDevice();
+	~SysportDevice() override;
 
-	virtual uint64 Read8(uint32 addr);
-	virtual uint64 Read16(uint32 addr);
-	virtual uint64 Write8(uint32 addr, uint32 data);
-	virtual uint64 Write16(uint32 addr, uint32 data);
-	virtual uint64 Peek8(uint32 addr);
+ protected:
+	// BusIO インタフェース
+	static const uint32 NPORT = 8;
+	uint64 Read(uint32 addr);
+	uint64 Write(uint32 addr, uint32 data);
+	uint64 Peek(uint32 addr);
 
  private:
-	// アドレスデコーダ
-	uint64 Decoder(uint32 addr) const;
-
 	struct SYSPORT sysport {};
 };