From f2b974acc54d913b286c5ff153dcb0bbb0dbce62 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Wed, 27 Apr 2022 22:57:36 -0500
Subject: [PATCH] SoundUnit: ring modulation

---
 src/engine/platform/sound/su.cpp | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/engine/platform/sound/su.cpp b/src/engine/platform/sound/su.cpp
index 69b02a78..a9e6d243 100644
--- a/src/engine/platform/sound/su.cpp
+++ b/src/engine/platform/sound/su.cpp
@@ -33,6 +33,10 @@ void SoundUnit::NextSample(short* l, short* r) {
         ns[i]=((((cycle[i]>>15)&127)>chan[i].duty)*127)^(short)SCtriangle[(cycle[i]>>14)&255];
         break;
     }
+
+    if (chan[i].flags.ring) {
+      ns[i]=(ns[i]*ns[(i+1)&7])>>7;
+    }
     
     if (chan[i].flags.pcm) {
       if (chan[i].freq>0x8000) {