From 89e057a2baafce2b339b12cedd21d940b35c8db0 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Sat, 24 Dec 2022 18:29:01 -0500
Subject: [PATCH] OPLL: fix possible overflow

---
 src/engine/platform/opll.cpp | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/engine/platform/opll.cpp b/src/engine/platform/opll.cpp
index d902e2422..0136123e3 100644
--- a/src/engine/platform/opll.cpp
+++ b/src/engine/platform/opll.cpp
@@ -248,6 +248,7 @@ void DivPlatformOPLL::tick(bool sysTick) {
       if (chan[i].freq<0) chan[i].freq=0;
       if (chan[i].freq>65535) chan[i].freq=65535;
       int freqt=toFreq(chan[i].freq);
+      if (freqt>2047) freqt=2047;
       chan[i].freqL=freqt&0xff;
       if (i>=6 && properDrums && (i<9 || !noTopHatFreq)) {
         immWrite(0x10+drumSlot[i],freqt&0xff);
@@ -257,7 +258,7 @@ void DivPlatformOPLL::tick(bool sysTick) {
           immWrite(0x10+i,freqt&0xff);
         }
       }
-      chan[i].freqH=freqt>>8;
+      chan[i].freqH=(freqt>>8)&15;
     }
     if (chan[i].keyOn && i>=6 && properDrums) {
       if (!isMuted[i]) {