From b78991fc83eaa0015eca9d81a858b65f2d786d49 Mon Sep 17 00:00:00 2001
From: Aaron Giles <aaron@aarongiles.com>
Date: Sat, 22 May 2021 13:28:30 -0700
Subject: [PATCH] ymfm: Fix OPL3 waveform 7 to better match hardware.

---
 3rdparty/ymfm/src/ymfm_opl.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/3rdparty/ymfm/src/ymfm_opl.cpp b/3rdparty/ymfm/src/ymfm_opl.cpp
index 108262f4b63..5819a411620 100644
--- a/3rdparty/ymfm/src/ymfm_opl.cpp
+++ b/3rdparty/ymfm/src/ymfm_opl.cpp
@@ -96,7 +96,7 @@ opl_registers_base<Revision>::opl_registers_base() :
 				wf4[index] = bitfield(index, 9) ? zeroval : wf0[index * 2];
 				wf5[index] = bitfield(index, 9) ? zeroval : wf0[(index * 2) & 0x1ff];
 				wf6[index] = bitfield(index, 9) << 15;
-				wf7[index] = (zeroval - wf0[(index / 2)]) | (bitfield(index, 9) << 15);
+				wf7[index] = (bitfield(index, 9) ? (index ^ 0x13ff) : index) << 3;
 			}
 		}
 	}