From 9403b6b84f084203ebab2406463eb75441d2d227 Mon Sep 17 00:00:00 2001
From: Vicki Pfau <vi@endrift.com>
Date: Sat, 8 Jul 2017 21:13:54 -0700
Subject: [PATCH] GB Audio: Fix zombie mode bit masking

---
 CHANGES        | 1 +
 src/gb/audio.c | 1 +
 2 files changed, 2 insertions(+)

diff --git a/CHANGES b/CHANGES
index d2e597da7..03887185d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -168,6 +168,7 @@ Bugfixes:
  - Qt: Fix shader selector on Ubuntu (fixes mgba.io/i/767)
  - GB Serialize: Fix timer serialization
  - GB Audio: Fix incorrect channel 4 iteration
+ - GB Audio: Fix zombie mode bit masking
 Misc:
  - Qt: Add language selector
  - GBA Timer: Improve accuracy of timers
diff --git a/src/gb/audio.c b/src/gb/audio.c
index 6a9abe0c7..1ec288162 100644
--- a/src/gb/audio.c
+++ b/src/gb/audio.c
@@ -702,6 +702,7 @@ bool _writeEnvelope(struct GBAudioEnvelope* envelope, uint8_t value) {
 	if (!envelope->stepTime) {
 		// TODO: Improve "zombie" mode
 		++envelope->currentVolume;
+		envelope->currentVolume &= 0xF;
 	}
 	_updateEnvelopeDead(envelope);
 	envelope->nextStep = envelope->stepTime;