--- nono/vm/dmac.h	2026/04/29 17:04:32	1.1.1.2
+++ nono/vm/dmac.h	2026/04/29 17:04:35	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
@@ -169,19 +170,15 @@ struct DMAC
 class DMACDevice
 	: public IODevice
 {
-	typedef IODevice inherited;
+	using inherited = IODevice;
 
 	static const int baseaddr = 0xe84000;
 
  public:
 	DMACDevice();
-	virtual ~DMACDevice();
+	~DMACDevice() override;
 
-	virtual uint64 Read8(uint32 addr);
-	virtual uint64 Write8(uint32 addr, uint32 data);
-	virtual uint64 Peek8(uint32 addr);
-
-	virtual bool MonitorUpdate();
+	bool MonitorUpdate() override;
 
 	// 転送
 	void AbortTransfer(DMAC::Channel *chan);
@@ -189,6 +186,13 @@ class DMACDevice
 	int64 TransferM8toD8(DMAC::Channel *chan);
 	int64 TransferD8toM8(DMAC::Channel *chan);
 
+ protected:
+	// BusIO インタフェース
+	static const uint NPORT = 256;
+	uint64 Read(uint32 addr);
+	uint64 Write(uint32 addr, uint32 data);
+	uint64 Peek(uint32 addr);
+
  private:
 	void MonitorReg4(int x, int y, uint32 reg, const char * const *names);