From 151df6adf9d63c9b8c8a61946243800610ac3a65 Mon Sep 17 00:00:00 2001
From: notaz <notasas@gmail.com>
Date: Sat, 7 Oct 2017 01:36:22 +0300
Subject: [PATCH] simple ym2612 fixes

---
 pico/sound/ym2612.c | 37 +++++++++----------------------------
 1 file changed, 9 insertions(+), 28 deletions(-)

diff --git a/pico/sound/ym2612.c b/pico/sound/ym2612.c
index 5c52785d..e712278b 100644
--- a/pico/sound/ym2612.c
+++ b/pico/sound/ym2612.c
@@ -1693,22 +1693,19 @@ int YM2612Write_(unsigned int a, unsigned int v)
 
 	v &= 0xff;	/* adjust to 8 bit bus */
 
-	switch( a&3){
+	switch( a & 3 ){
 	case 0:	/* address port 0 */
+	case 2:	/* address port 1 */
 		ym2612.OPN.ST.address = v;
-		ym2612.addr_A1 = 0;
-		ret=0;
+		ym2612.addr_A1 = (a & 2) >> 1;
+		ret = 0;
 		break;
 
-	case 1:	/* data port 0    */
-		if (ym2612.addr_A1 != 0) {
-			ret=0;
-			break;	/* verified on real YM2608 */
-		}
-
-		addr = ym2612.OPN.ST.address;
+	case 1:
+	case 3:	/* data port */
+		addr = ym2612.OPN.ST.address | ((int)ym2612.addr_A1 << 8);
 
-		switch( addr & 0xf0 )
+		switch( addr & 0x1f0 )
 		{
 		case 0x20:	/* 0x20-0x2f Mode */
 			switch( addr )
@@ -1721,6 +1718,7 @@ int YM2612Write_(unsigned int a, unsigned int v)
 				else
 				{
 					ym2612.OPN.lfo_inc = 0;
+					ym2612.OPN.lfo_cnt = 0;
 				}
 				break;
 #if 0 // handled elsewhere
@@ -1790,23 +1788,6 @@ int YM2612Write_(unsigned int a, unsigned int v)
 			ret = OPNWriteReg(addr,v);
 		}
 		break;
-
-	case 2:	/* address port 1 */
-		ym2612.OPN.ST.address = v;
-		ym2612.addr_A1 = 1;
-		ret=0;
-		break;
-
-	case 3:	/* data port 1    */
-		if (ym2612.addr_A1 != 1) {
-			ret=0;
-			break;	/* verified on real YM2608 */
-		}
-
-		addr = ym2612.OPN.ST.address | 0x100;
-
-		ret = OPNWriteReg(addr, v);
-		break;
 	}
 
 	return ret;
-- 
2.39.5