--- nono/vm/fdc.h	2026/04/29 17:05:18	1.1.1.9
+++ nono/vm/fdc.h	2026/04/29 17:05:25	1.1.1.10
@@ -278,7 +278,7 @@ class FDCDevice : public IODevice
 
  public:
 	FDCDevice();
-	virtual ~FDCDevice() override;
+	~FDCDevice() override;
 
 	bool Create() override;
 	bool Init() override;
@@ -297,9 +297,9 @@ class FDCDevice : public IODevice
  protected:
 	// BusIO インタフェース
 	static const uint32 NPORT = 4;
-	uint64 Read(uint32 offset);
-	uint64 Write(uint32 offset, uint32 data);
-	uint64 Peek(uint32 offset);
+	busdata Read(uint32 offset);
+	busdata Write(uint32 offset, uint32 data);
+	busdata Peek(uint32 offset);
 
  private:
 	uint32 ReadData();
@@ -417,7 +417,7 @@ class FDCDevice : public IODevice
 	FixedQueue<uint8, 1> dreg {};	// 内部データレジスタ
 
 	bool hd {};					// Head address
-	uint8 us {};				// Unit Select
+	uint8 us {};				// Unit Select (US0,US1) 出力信号
 	bool tc {};					// TC 入力信号
 	bool dack {};				// DACK 入力信号