From b24c5726328ec66e162bbe43dbbc59235c5f559d Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Tue, 15 Feb 2022 15:19:36 -0500
Subject: [PATCH] prevent division by zero, part 1

---
 src/engine/engine.cpp           | 2 +-
 src/engine/platform/genesis.cpp | 5 +++--
 src/engine/platform/pce.cpp     | 2 +-
 src/engine/platform/tia.cpp     | 1 +
 4 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/engine/engine.cpp b/src/engine/engine.cpp
index 9129c874..fab98860 100644
--- a/src/engine/engine.cpp
+++ b/src/engine/engine.cpp
@@ -4017,7 +4017,7 @@ SafeWriter* DivEngine::saveVGM(bool* sysToExport, bool loop) {
         }
       }
       if (nextToTouch>=0) {
-        double waitTime=totalWait+(loopTimer[nextToTouch]*(44100.0/loopFreq[nextToTouch]));
+        double waitTime=totalWait+(loopTimer[nextToTouch]*(44100.0/MIN(1,loopFreq[nextToTouch])));
         if (waitTime>0) {
           w->writeC(0x61);
           w->writeS(waitTime);
diff --git a/src/engine/platform/genesis.cpp b/src/engine/platform/genesis.cpp
index e580e2cc..945ec60b 100644
--- a/src/engine/platform/genesis.cpp
+++ b/src/engine/platform/genesis.cpp
@@ -385,7 +385,8 @@ void DivPlatformGenesis::tick() {
             off=8363.0/(double)s->centerRate;
           }
         }
-        dacRate=(1280000*1.25*off)/chan[i].baseFreq;
+        dacRate=(1280000*1.25*off)/MIN(1,chan[i].baseFreq);
+        if (dacRate<1) dacRate=1;
         if (dumpWrites) addWrite(0xffff0001,1280000/dacRate);
       }
       chan[i].freqChanged=false;
@@ -514,7 +515,7 @@ int DivPlatformGenesis::dispatch(DivCommand c) {
           }
           dacPos=0;
           dacPeriod=0;
-          dacRate=1280000/parent->song.sample[dacSample]->rate;
+          dacRate=1280000/MIN(1,parent->song.sample[dacSample]->rate);
           if (dumpWrites) addWrite(0xffff0001,parent->song.sample[dacSample]->rate);
           chan[c.chan].furnaceDac=false;
         }
diff --git a/src/engine/platform/pce.cpp b/src/engine/platform/pce.cpp
index df11d6da..301f8509 100644
--- a/src/engine/platform/pce.cpp
+++ b/src/engine/platform/pce.cpp
@@ -209,7 +209,7 @@ void DivPlatformPCE::tick() {
             off=8363.0/(double)s->centerRate;
           }
         }
-        chan[i].dacRate=((double)chipClock/2)/(off*chan[i].freq);
+        chan[i].dacRate=((double)chipClock/2)/MIN(1,off*chan[i].freq);
         if (dumpWrites) addWrite(0xffff0001+(i<<8),chan[i].dacRate);
       }
       if (chan[i].freq>4095) chan[i].freq=4095;
diff --git a/src/engine/platform/tia.cpp b/src/engine/platform/tia.cpp
index 9f97a7e5..f2c23310 100644
--- a/src/engine/platform/tia.cpp
+++ b/src/engine/platform/tia.cpp
@@ -57,6 +57,7 @@ unsigned char DivPlatformTIA::dealWithFreq(unsigned char shape, int base, int pi
   }
   int bp=base+pitch;
   double mult=0.25*(parent->song.tuning*0.0625)*pow(2.0,double(768+bp)/(256.0*12.0));
+  if (mult<0.5) mult=0.5;
   switch (shape) {
     case 1: // buzzy
       return ceil(31400/(30.6*mult))-1;