--- nono/vm/opm.cpp	2026/04/29 17:04:45	1.1
+++ nono/vm/opm.cpp	2026/04/29 17:05:09	1.1.1.4
@@ -4,38 +4,76 @@
 // Licensed under nono-license.txt
 //
 
+//
+// OPM (YM2151)
+//
+
 #include "opm.h"
+#include "mpu.h"
+#include "fdc.h"
 
-std::unique_ptr<OPMDevice> gOPM;
+// グローバル参照用
+OPMDevice *gOPM;
 
+// コンストラクタ
 OPMDevice::OPMDevice()
+	: inherited("OPM")
 {
-	logname = "opm";
-	devname = "OPM";
 	devaddr = baseaddr;
 	devlen  = 0x2000;
 }
 
+// デストラクタ
 OPMDevice::~OPMDevice()
 {
+	gOPM = NULL;
 }
 
 uint64
-OPMDevice::Read(uint32 addr)
+OPMDevice::Read(uint32 offset)
 {
-	putlog(0, "未実装読み込み +$%02x", addr);
-	return 0;
+	switch (offset) {
+	 case 0:
+		putlog(0, "未実装読み込み $%06x", gMPU->GetPaddr());
+		return 0;
+	 case 1:
+		// OPM ステータスレジスタ
+		putlog(0, "未実装OPMステータスレジスタ読み込み");
+		return 0;
+	 default:
+		__unreachable();
+	}
 }
 
 uint64
-OPMDevice::Write(uint32 addr, uint32 data)
+OPMDevice::Write(uint32 offset, uint32 data)
 {
-	putlog(0, "未実装書き込み +$%02x <- $%02x", addr, data);
+	switch (offset) {
+	 case 0:
+		putlog(1, "REG <- $%02x", data);
+		reg = data;
+		break;
+	 case 1:
+		putlog(1, "DATA <- $%02x", data);
+		switch (reg) {
+		 case 0x1b:
+			gFDC->SetForceReady(reg & 0x40);
+			// 他のビットは未対応
+			break;
+		 default:
+			putlog(0, "未実装書き込み $%06x <- $%02x", gMPU->GetPaddr(), data);
+			break;
+		}
+		break;
+	 default:
+		__unreachable();
+	}
+
 	return 0;
 }
 
 uint64
-OPMDevice::Peek(uint32 addr)
+OPMDevice::Peek(uint32 offset)
 {
 	// XXX 未実装
 	return 0xff;