--- nono/vm/iocon.cpp	2026/04/29 17:04:28	1.1
+++ nono/vm/iocon.cpp	2026/04/29 17:04:32	1.1.1.2
@@ -6,7 +6,7 @@
 #include "iocon.h"
 #include "mpu.h"
 
-IOConDevice *gIOCon;
+std::unique_ptr<IOConDevice> gIOCon;
 
 IOConDevice::IOConDevice()
 {
@@ -20,12 +20,24 @@ IOConDevice::~IOConDevice()
 {
 }
 
+inline uint64
+IOConDevice::Decoder(uint32 addr) const
+{
+	// 折り返しは?
+	addr -= baseaddr;
+
+	// 偶数アドレスはバスエラー
+	if ((addr & 1) == 0)
+		return (uint64)-1;
+
+	return addr >> 1;
+}
+
 uint64
 IOConDevice::Read8(uint32 addr)
 {
-	uint32 offset = addr - baseaddr;
-	switch (offset) {
-	 case 1:	// $E9C001 割り込みステータス
+	switch (Decoder(addr)) {
+	 case 0:	// $E9C001 割り込みステータス
 		return (fdc_int ? 0x80 : 0)
 			|  (fdd_int ? 0x40 : 0)
 			|  (prt_int ? 0x20 : 0)
@@ -34,7 +46,7 @@ IOConDevice::Read8(uint32 addr)
 			|  (fdc_en  ? 0x04 : 0)
 			|  (fdd_en  ? 0x02 : 0)
 			|  (prt_en  ? 0x01 : 0);
-	 case 3:	// $E9C003 割り込みベクタ
+	 case 1:	// $E9C003 割り込みベクタ
 		return vector;
 		break;
 	}
@@ -50,9 +62,8 @@ IOConDevice::Read16(uint32 addr)
 uint64
 IOConDevice::Write8(uint32 addr, uint32 data)
 {
-	uint32 offset = addr - baseaddr;
-	switch (offset) {
-	 case 1:	// $E9C001 割り込みマスク
+	switch (Decoder(addr)) {
+	 case 0:	// $E9C001 割り込みマスク
 		hdd_en = (data & 0x08);
 		fdc_en = (data & 0x04);
 		fdd_en = (data & 0x02);
@@ -60,7 +71,7 @@ IOConDevice::Write8(uint32 addr, uint32
 		putlog(1, "割り込みマスク設定 HDD=%d FDC=%d FDD=%d PRT=%d",
 			hdd_en, fdc_en, fdd_en, prt_en);
 		return 0;
-	 case 3:	// $E9C003 割り込みベクタ
+	 case 1:	// $E9C003 割り込みベクタ
 		vector = data & 0xfc;
 		putlog(1, "割り込みベクタ設定 $%02x", vector);
 		return 0;
@@ -79,9 +90,8 @@ IOConDevice::Write16(uint32 addr, uint32
 uint64
 IOConDevice::Peek8(uint32 addr)
 {
-	uint32 offset = addr - baseaddr;
-	switch (offset) {
-	 case 1:
+	switch (Decoder(addr)) {
+	 case 0:
 		return (fdc_int ? 0x80 : 0)
 			|  (fdd_int ? 0x40 : 0)
 			|  (prt_int ? 0x20 : 0)
@@ -91,7 +101,7 @@ IOConDevice::Peek8(uint32 addr)
 			|  (fdd_en  ? 0x02 : 0)
 			|  (prt_en  ? 0x01 : 0);
 
-	 case 3:
+	 case 1:
 		return vector;
 
 	 default:
@@ -106,7 +116,7 @@ IOConDevice::IntFDC()
 	fdc_int = true;
 	if (fdc_en) {
 		putlog(1, "FDC からの割り込み要求");
-		gMPU->Interrupt(1, vector + 0);
+		gMPU680x0->Interrupt(1, vector + 0);
 	} else {
 		putlog(2, "FDC からの割り込み要求(マスク)");
 	}