research/opl/dosbox-trace/dosbox-trace.diff

--- dosbox-0.72-clean/src/hardware/adlib.cpp	2009-02-19 18:12:05.000000000 +0000
+++ dosbox-0.72/src/hardware/adlib.cpp	2009-03-12 18:15:41.000000000 +0000
@@ -135,15 +135,17 @@
 
 static Bitu OPL_Read(Bitu port,Bitu iolen) {
 	Bitu addr=port & 3;
+	Bitu result = 0xff;
 	switch (opl.mode) {
 	case OPL_opl2:
-		return OPL2::YM3812Read(0,addr);
+		result = OPL2::YM3812Read(0,addr);
 	case OPL_dualopl2:
-		return OPL2::YM3812Read(addr>>1,addr);
+		result = OPL2::YM3812Read(addr>>1,addr);
 	case OPL_opl3:
-		return THEOPL3::YMF262Read(0,addr);
+		result = THEOPL3::YMF262Read(0,addr);
 	}
-	return 0xff;
+	printf("OPL_read: %x -> %x\n", addr, result);
+	return result;
 }
 
 static void OPL_RawAdd(Bitu index,Bitu val);
@@ -160,6 +162,7 @@
 		if (opl.raw.capturing) OPL_RawAdd(index,val);
 	} else opl.raw.cmd[port>>1]=val;
 	if (!port) adlib_commandreg=val;
+	printf("OPL_write: %x, %x\n", port, val);
 	switch (opl.mode) {
 	case OPL_opl2:
 		OPL2::YM3812Write(0,port,val);