--- nono/vm/fdc.h	2026/04/29 17:05:18	1.1.1.9
+++ nono/vm/fdc.h	2026/04/29 17:05:30	1.1.1.11
@@ -85,7 +85,7 @@ struct FDCCmdBuf
 		};
 	};
 
-	int len;
+	uint len;
 
 	void Clear() {
 		len = 0;
@@ -144,11 +144,11 @@ struct FDCResBuf
 class FDCDevice : public IODevice
 {
 	using inherited = IODevice;
-	static const int baseaddr = 0xe94000;
+	static const uint32 baseaddr = 0xe94000;
 
  public:
 	// サポートしているドライブ数上限
-	static const int MAX_DRIVE = 4;
+	static const uint MAX_DRIVE = 4;
 
  private:
 	// コマンド定義
@@ -278,7 +278,7 @@ class FDCDevice : public IODevice
 
  public:
 	FDCDevice();
-	virtual ~FDCDevice() override;
+	~FDCDevice() override;
 
 	bool Create() override;
 	bool Init() override;
@@ -297,9 +297,10 @@ 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 ReadPort(uint32 offset);
+	busdata WritePort(uint32 offset, uint32 data);
+	busdata PeekPort(uint32 offset);
+	bool PokePort(uint32 offset, uint32 data);
 
  private:
 	uint32 ReadData();
@@ -309,7 +310,7 @@ class FDCDevice : public IODevice
 
 	uint32 GetDriveStatus() const;
 	void PushDreg(uint8);
-	int PopDreg();
+	uint32 PopDreg();
 	void RequestDataByte();
 
 	uint8 GetMSR() const;
@@ -417,7 +418,7 @@ 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
 
@@ -432,7 +433,7 @@ class FDCDevice : public IODevice
 	uint sect_remain {};
 	int index_detected {};
 
-	int seek_srt {};			// SEEK ステップレートタイマカウンタ
+	uint seek_srt {};			// SEEK ステップレートタイマカウンタ
 
 	MSR msr {};
 	ST0 st0 {};