--- nono/vm/romemu_x68k.cpp	2026/04/29 17:05:17	1.1.1.2
+++ nono/vm/romemu_x68k.cpp	2026/04/29 17:05:25	1.1.1.3
@@ -96,7 +96,7 @@ ROM30EmuDevice::Init()
 	return true;
 }
 
-uint64
+busdata
 ROM30EmuDevice::Read32(uint32 addr)
 {
 	// IPLROM2 領域からのロングワードアクセスでだけ謎の I/O 空間が見える。
@@ -124,7 +124,7 @@ ROM30EmuDevice::SCSIBoot() const
 	auto mainram = GetMainRAMDevice();
 	auto sram = GetSRAMDevice();
 
-	auto mpu680x0 = dynamic_cast<MPU680x0Device*>(mpu);
+	auto mpu680x0 = GetMPU680x0Device(mpu);
 	m68kreg& reg = mpu680x0->reg;
 
 	// SRAM の ROM 起動アドレスから SCSI ID を取得。
@@ -206,7 +206,7 @@ ROM30EmuDevice::SCSIBoot() const
 uint32
 ROM30EmuDevice::SCSIIOCS()
 {
-	auto mpu680x0 = dynamic_cast<MPU680x0Device*>(mpu);
+	auto mpu680x0 = GetMPU680x0Device(mpu);
 	m68kreg& reg = mpu680x0->reg;
 
 	uint32 scsicall = reg.D[1];
@@ -234,7 +234,7 @@ ROM30EmuDevice::SCSIIOCS()
 }
 
 #define PRE	\
-	auto mpu680x0 = dynamic_cast<MPU680x0Device*>(mpu);	\
+	auto mpu680x0 = GetMPU680x0Device(mpu);	\
 	m68kreg& reg = mpu680x0->reg;	\
 	uint32 d4 = reg.D[4];	\
 	uint32 id = d4 & 0x0000ffff;	\
@@ -262,9 +262,9 @@ ROM30EmuDevice::SCSI_S_INQUIRY(uint32 sc
 {
 	PRE;
 
-	uint32 a1 = reg.A[1];
+	busaddr a1(reg.A[1], busaddr::S);
 	uint32 reqlen = reg.D[3];
-	putlog(1, "%s a1=$%06x", loghdr.c_str(), a1);
+	putlog(1, "%s a1=$%06x", loghdr.c_str(), a1.Addr());
 	std::vector<uint8> cmdseq(6);
 	cmdseq[0] = SCSI::Command::Inquiry;
 	cmdseq[1] = lun << 5;
@@ -282,8 +282,8 @@ ROM30EmuDevice::SCSI_S_INQUIRY(uint32 sc
 	// アロケーションサイズ(reqlen)と結果(cmd->buf)の小さい方まで転送
 	int len = std::min((int)reqlen, (int)res.size());
 	for (int i = 0; i < len; i++) {
-		int64 r = mainbus->Write8(a1++, res[i]);
-		if (r < 0) {
+		busdata bd = mainbus->Write8(a1++, res[i]);
+		if (bd.IsBusErr()) {
 			return -1;
 		}
 	}
@@ -295,7 +295,7 @@ ROM30EmuDevice::SCSI_S_READEXT(uint32 sc
 {
 	PRE;
 
-	uint32 a1 = reg.A[1];
+	busaddr a1(reg.A[1], busaddr::S);
 	uint32 lba = reg.D[2];
 	uint32 blkcount = reg.D[3];
 	uint32 blkshift = reg.D[5];
@@ -304,7 +304,7 @@ ROM30EmuDevice::SCSI_S_READEXT(uint32 sc
 	uint32 bytes = blkcount * blkbytes;
 
 	putlog(1, "%s a1=$%06x lba=$%08x bytes=%d d5=%d",
-		loghdr.c_str(), a1, lba, bytes, blkshift);
+		loghdr.c_str(), a1.Addr(), lba, bytes, blkshift);
 	std::vector<uint8> cmdseq(10);
 	cmdseq[0] = SCSI::Command::Read10;
 	cmdseq[1] = lun << 5;
@@ -337,8 +337,8 @@ ROM30EmuDevice::SCSI_S_READEXT(uint32 sc
 	}
 
 	for (int i = 0; i < bytes; i++) {
-		int64 r = mainbus->Write8(a1++, res[i]);
-		if (r < 0) {
+		busdata bd = mainbus->Write8(a1++, res[i]);
+		if (bd.IsBusErr()) {
 			return -1;
 		}
 	}
@@ -359,8 +359,8 @@ ROM30EmuDevice::SCSI_S_READCAP(uint32 sc
 {
 	PRE;
 
-	uint32 a1 = reg.A[1];
-	putlog(1, "%s a1=$%06x", loghdr.c_str(), a1);
+	busaddr a1(reg.A[1], busaddr::S);
+	putlog(1, "%s a1=$%06x", loghdr.c_str(), a1.Addr());
 	std::vector<uint8> cmdseq(10);
 	cmdseq[0] = SCSI::Command::ReadCapacity;
 	cmdseq[1] = lun << 5;
@@ -376,8 +376,8 @@ ROM30EmuDevice::SCSI_S_READCAP(uint32 sc
 	const std::vector<uint8>& res = cmd->buf;
 	assert(res.size() == 8);
 	for (auto data : res) {
-		int64 r = mainbus->Write8(a1++, data);
-		if (r < 0) {
+		busdata bd = mainbus->Write8(a1++, data);
+		if (bd.IsBusErr()) {
 			return -1;
 		}
 	}