--- nono/vm/opm.cpp	2026/04/29 17:05:16	1.1.1.6
+++ nono/vm/opm.cpp	2026/04/29 17:05:24	1.1.1.7
@@ -50,17 +50,16 @@ OPMDevice::ResetHard(bool poweron)
 	fdc->SetForceReady(false);
 }
 
-uint64
+busdata
 OPMDevice::Read(uint32 offset)
 {
-	uint8 data;
-
-	mpu->AddCycle(19);	// InsideOut p.135
+	busdata data;
 
 	switch (offset) {
 	 case 0:
 		putlog(0, "Read $%06x (NOT IMPLEMENTED)", mpu->GetPaddr());
-		return 0;
+		data = 0;
+		break;
 	 case 1:
 		// OPM ステータスレジスタ
 		data = 0;
@@ -69,19 +68,24 @@ OPMDevice::Read(uint32 offset)
 		}
 		// タイマ関係の bit1, bit0 は未実装
 
-		putlog(1, "STAT -> $%02x", data);
-		return data;
+		putlog(1, "STAT -> $%02x", data.Data());
+		break;
 	 default:
 		VMPANIC("corrupted offset=%d", offset);
-		return 0xff;
+		data = 0xff;
+		break;
 	}
+
+	// InsideOut p.135
+	const busdata read_wait = busdata::Wait(19 * 40_usec);
+	data |= read_wait;
+
+	return data;
 }
 
-uint64
+busdata
 OPMDevice::Write(uint32 offset, uint32 data)
 {
-	mpu->AddCycle(53);	// InsideOut p.135
-
 	uint64 now = scheduler->GetVirtTime();
 
 	switch (offset) {
@@ -136,10 +140,13 @@ OPMDevice::Write(uint32 offset, uint32 d
 		break;
 	}
 
-	return 0;
+	// InsideOut p.135
+	const busdata write_wait = busdata::Wait(53 * 40_nsec);
+
+	return write_wait;
 }
 
-uint64
+busdata
 OPMDevice::Peek(uint32 offset)
 {
 	// XXX 未実装