From 15d66422a9d9404066a143298f092163834c2725 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        | 2 ++
 src/gb/audio.c | 1 +
 2 files changed, 3 insertions(+)

diff --git a/CHANGES b/CHANGES
index 0a46be2c2..21b34a1d2 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,4 +1,6 @@
 0.7.0: (Future)
+Bugfixes:
+ - GB Audio: Fix zombie mode bit masking
 Misc:
  - GBA Timer: Use global cycles for timers
 
diff --git a/src/gb/audio.c b/src/gb/audio.c
index 3b384cdf8..3f4435731 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;