From 5ffda66f2257358f5f7290276d9201d92b2a98a5 Mon Sep 17 00:00:00 2001
From: tildearrow <tildearrow@protonmail.com>
Date: Sun, 20 Feb 2022 21:54:03 -0500
Subject: [PATCH] NES: better channel muting

---
 src/engine/platform/nes.cpp         | 10 ++++------
 src/engine/platform/sound/nes/apu.h | 11 ++++++-----
 2 files changed, 10 insertions(+), 11 deletions(-)

diff --git a/src/engine/platform/nes.cpp b/src/engine/platform/nes.cpp
index 0b8b3dc26..628cecb5d 100644
--- a/src/engine/platform/nes.cpp
+++ b/src/engine/platform/nes.cpp
@@ -428,10 +428,7 @@ int DivPlatformNES::dispatch(DivCommand c) {
 
 void DivPlatformNES::muteChannel(int ch, bool mute) {
   isMuted[ch]=mute;
-  rWrite(0x4015,(!isMuted[0])|((!isMuted[1])<<1)|((!isMuted[2])<<2)|((!isMuted[3])<<3)|((!isMuted[4])<<4));
-  if (isMuted[4]) {
-    rWrite(0x4011,0);
-  }
+  nes->muted[ch]=mute;
 }
 
 void DivPlatformNES::forceIns() {
@@ -465,7 +462,7 @@ void DivPlatformNES::reset() {
   nes->apu.cpu_cycles=0;
   nes->apu.cpu_opcode_cycle=0;
 
-  rWrite(0x4015,(!isMuted[0])|((!isMuted[1])<<1)|((!isMuted[2])<<2)|((!isMuted[3])<<3)|((!isMuted[4])<<4));
+  rWrite(0x4015,0x1f);
   rWrite(0x4001,chan[0].sweep);
   rWrite(0x4005,chan[1].sweep);
 }
@@ -510,10 +507,11 @@ int DivPlatformNES::init(DivEngine* p, int channels, int sugRate, unsigned int f
   apuType=flags;
   dumpWrites=false;
   skipRegisterWrites=false;
+  nes=new struct NESAPU;
   for (int i=0; i<5; i++) {
     isMuted[i]=false;
+    nes->muted[i]=false;
   }
-  nes=new struct NESAPU;
   setFlags(flags);
 
   init_nla_table(500,500);
diff --git a/src/engine/platform/sound/nes/apu.h b/src/engine/platform/sound/nes/apu.h
index 4d3649e0d..93cf72fef 100644
--- a/src/engine/platform/sound/nes/apu.h
+++ b/src/engine/platform/sound/nes/apu.h
@@ -338,15 +338,15 @@ enum apu_mode { APU_60HZ, APU_48HZ };
 #define _apu_channel_volume_adjust(ch, index)\
 	((ch))
 #define s1_out(a)\
-	_apu_channel_volume_adjust(a->S1.output, APU_S1)
+	(a->muted[0] ? 0 : _apu_channel_volume_adjust(a->S1.output, APU_S1))
 #define s2_out(a)\
-	_apu_channel_volume_adjust(a->S2.output, APU_S2)
+	(a->muted[1] ? 0 : _apu_channel_volume_adjust(a->S2.output, APU_S2))
 #define tr_out(a)\
-	_apu_channel_volume_adjust(a->TR.output, APU_TR)
+	(a->muted[2] ? 0 : _apu_channel_volume_adjust(a->TR.output, APU_TR))
 #define ns_out(a)\
-	_apu_channel_volume_adjust(a->NS.output, APU_NS)
+	(a->muted[3] ? 0 : _apu_channel_volume_adjust(a->NS.output, APU_NS))
 #define dmc_out(a)\
-	_apu_channel_volume_adjust(a->DMC.output, APU_DMC)
+	(a->muted[4] ? 0 : _apu_channel_volume_adjust(a->DMC.output, APU_DMC))
 #define extra_out(ch)\
 	(ch * cfg->apu.channel[APU_EXTRA])
 #define pulse_output(a)\
@@ -523,6 +523,7 @@ EXTERNC struct NESAPU {
   _apuTriangle TR;
   _apuNoise NS;
   _apuDMC DMC;
+  unsigned char muted[5];
 };
 
 /* apuPeriod[mode][type][cycles] */