From 420a22b5c743c7c9162bf52454bd9af631898f2a Mon Sep 17 00:00:00 2001
From: Barry Harris <44396066+barry65536@users.noreply.github.com>
Date: Fri, 13 Jan 2012 16:32:59 +0000
Subject: [PATCH] Normalised SN76496 sound volume in Exed Exes, Ikki, Lady Bug,
 Mr Do, Super Locomotive, Return of the Invaders and Megadrive drivers

---
 src/burn/drivers/megadrive/megadrive.cpp    |  3 +++
 src/burn/drivers/misc_pre90s/d_exedexes.cpp | 16 ++++++----------
 src/burn/drivers/misc_pre90s/d_ikki.cpp     |  2 ++
 src/burn/drivers/misc_pre90s/d_ladybug.cpp  |  7 +++++++
 src/burn/drivers/misc_pre90s/d_mrdo.cpp     |  2 ++
 src/burn/drivers/sega/d_suprloco.cpp        |  2 ++
 src/burn/drivers/taito/d_retofinv.cpp       |  2 ++
 7 files changed, 24 insertions(+), 10 deletions(-)

diff --git a/src/burn/drivers/megadrive/megadrive.cpp b/src/burn/drivers/megadrive/megadrive.cpp
index 1c32895c9..329befd47 100644
--- a/src/burn/drivers/megadrive/megadrive.cpp
+++ b/src/burn/drivers/megadrive/megadrive.cpp
@@ -1137,6 +1137,7 @@ static INT32 MegadriveResetDo()
 		
 		SN76496Exit();
 		SN76496Init(0, OSC_PAL / 15, 1);
+		SN76496SetVolShift(0, 1);
 	} else {
 		BurnSetRefreshRate(60.0);
 		Reinitialise();
@@ -1149,6 +1150,7 @@ static INT32 MegadriveResetDo()
 		
 		SN76496Exit();
 		SN76496Init(0, OSC_NTSC / 15, 1);
+		SN76496SetVolShift(0, 1);
 	}
 
 	// other reset
@@ -2965,6 +2967,7 @@ INT32 MegadriveInit()
 	BurnTimerAttachSek(OSC_NTSC / 7);
 	
 	SN76496Init(0, OSC_NTSC / 15, 1);
+	SN76496SetVolShift(0, 1);
 	
 	MegadriveSetupSRAM();
 	SetupCustomCartridgeMappers();
diff --git a/src/burn/drivers/misc_pre90s/d_exedexes.cpp b/src/burn/drivers/misc_pre90s/d_exedexes.cpp
index 86478b573..9eb8148d6 100644
--- a/src/burn/drivers/misc_pre90s/d_exedexes.cpp
+++ b/src/burn/drivers/misc_pre90s/d_exedexes.cpp
@@ -437,6 +437,8 @@ static INT32 DrvInit()
 
 	SN76489Init(0, 3000000, 0);
 	SN76489Init(1, 3000000, 1);
+	SN76496SetVolShift(0, 2);
+	SN76496SetVolShift(1, 2);
 
 	GenericTilesInit();
 
@@ -664,7 +666,7 @@ static INT32 DrvFrame()
 		SN76496Update(0, pBurnSoundOut, nBurnSoundLen);
 		SN76496Update(1, pBurnSoundOut, nBurnSoundLen);
 
-		INT32 nSample, nSample0, nSample1;
+		INT32 nSample;
 		if (nBurnSoundLen) {
 			AY8910Update(0, &pAY8910Buffer[0], nBurnSoundLen);
 			for (INT32 n = 0; n < nBurnSoundLen; n++) {
@@ -672,18 +674,12 @@ static INT32 DrvFrame()
 				nSample += pAY8910Buffer[1][n];
 				nSample += pAY8910Buffer[2][n];
 
-				nSample >>= 2;
+				nSample >>= 4;
 
 				nSample = BURN_SND_CLIP(nSample);
 				
-				nSample0 = pBurnSoundOut[(n << 1) + 0] >> 2;
-				nSample1 = pBurnSoundOut[(n << 1) + 1] >> 2;
-				
-				nSample0 = BURN_SND_CLIP(nSample0 + nSample);
-				nSample1 = BURN_SND_CLIP(nSample1 + nSample);
-
-				pBurnSoundOut[(n << 1) + 0] = nSample0;
-				pBurnSoundOut[(n << 1) + 1] = nSample1;
+				pBurnSoundOut[(n << 1) + 0] += nSample;
+				pBurnSoundOut[(n << 1) + 1] += nSample;
  			}
 		}
 	}
diff --git a/src/burn/drivers/misc_pre90s/d_ikki.cpp b/src/burn/drivers/misc_pre90s/d_ikki.cpp
index 1bef4de1e..cb88241ef 100644
--- a/src/burn/drivers/misc_pre90s/d_ikki.cpp
+++ b/src/burn/drivers/misc_pre90s/d_ikki.cpp
@@ -357,6 +357,8 @@ static INT32 DrvInit()
 
 	SN76489Init(0, 8000000/4, 0);
 	SN76489Init(1, 8000000/2, 1);
+	SN76496SetVolShift(0, 2);
+	SN76496SetVolShift(1, 2);
 
 	GenericTilesInit();
 
diff --git a/src/burn/drivers/misc_pre90s/d_ladybug.cpp b/src/burn/drivers/misc_pre90s/d_ladybug.cpp
index 74d8e0e22..0a34002e2 100644
--- a/src/burn/drivers/misc_pre90s/d_ladybug.cpp
+++ b/src/burn/drivers/misc_pre90s/d_ladybug.cpp
@@ -776,6 +776,8 @@ static INT32 DrvInit(INT32 game_select)
 
 	SN76489Init(0, 4000000, 0);
 	SN76489Init(1, 4000000, 1);
+	SN76496SetVolShift(0, 2);
+	SN76496SetVolShift(1, 2);
 
 	GenericTilesInit();
 
@@ -859,6 +861,11 @@ static INT32 SraiderInit()
 	SN76489Init(2, 4000000, 1);
 	SN76489Init(3, 4000000, 1);
 	SN76489Init(4, 4000000, 1);
+	SN76496SetVolShift(0, 3);
+	SN76496SetVolShift(1, 3);
+	SN76496SetVolShift(2, 3);
+	SN76496SetVolShift(3, 3);
+	SN76496SetVolShift(4, 3);
 
 	GenericTilesInit();
 
diff --git a/src/burn/drivers/misc_pre90s/d_mrdo.cpp b/src/burn/drivers/misc_pre90s/d_mrdo.cpp
index ee845c82b..bea74feb6 100644
--- a/src/burn/drivers/misc_pre90s/d_mrdo.cpp
+++ b/src/burn/drivers/misc_pre90s/d_mrdo.cpp
@@ -304,6 +304,8 @@ static INT32 DrvInit()
 
 	SN76489Init(0, 4000000, 0);
 	SN76489Init(1, 4000000, 1);
+	SN76496SetVolShift(0, 1);
+	SN76496SetVolShift(1, 1);
  
 	DrvDoReset();
 
diff --git a/src/burn/drivers/sega/d_suprloco.cpp b/src/burn/drivers/sega/d_suprloco.cpp
index d1b37f4a8..b06da01d8 100644
--- a/src/burn/drivers/sega/d_suprloco.cpp
+++ b/src/burn/drivers/sega/d_suprloco.cpp
@@ -431,6 +431,8 @@ static INT32 DrvInit()
 
 	SN76489Init(0, 4000000, 0);
 	SN76489Init(1, 2000000, 1);
+	SN76496SetVolShift(0, 1);
+	SN76496SetVolShift(1, 1);
 
 	GenericTilesInit();
 
diff --git a/src/burn/drivers/taito/d_retofinv.cpp b/src/burn/drivers/taito/d_retofinv.cpp
index ce6ea3a64..b33f63c19 100644
--- a/src/burn/drivers/taito/d_retofinv.cpp
+++ b/src/burn/drivers/taito/d_retofinv.cpp
@@ -587,6 +587,8 @@ static INT32 DrvInit()
 
 	SN76489Init(0, 18432000 / 6, 0);
 	SN76489Init(1, 18432000 / 6, 1);
+	SN76496SetVolShift(0, 2);
+	SN76496SetVolShift(1, 2);
 
 	GenericTilesInit();