From c524a62c4069e16e20b361845cb7351414118d15 Mon Sep 17 00:00:00 2001
From: OBattler <oubattler@gmail.com>
Date: Wed, 8 Jan 2020 19:01:24 +0100
Subject: [PATCH] Fixed an intance of undefined behavior in sb_mpu401.c.

---
 src/sound/snd_mpu401.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/sound/snd_mpu401.c b/src/sound/snd_mpu401.c
index 5b4d2635b..03916ae3e 100644
--- a/src/sound/snd_mpu401.c
+++ b/src/sound/snd_mpu401.c
@@ -1216,7 +1216,8 @@ MPU401_Event(void *priv)
 	mpu->clock.cth_counter++;
 	if (mpu->clock.cth_counter >= mpu->clock.cth_rate[mpu->clock.cth_mode]) {
 		mpu->clock.cth_counter = 0;
-		mpu->clock.cth_mode= (++mpu->clock.cth_mode) % 4;
+		mpu->clock.cth_mode++;
+		mpu->clock.cth_mode %= 4;
 		mpu->state.req_mask |= (1 << 13);
 	}
     }