diff -urN 10-STYMulator-0.21a_avoid_ambiguous_else/src/stsoundlib/YmMusic.cpp 11-STYMulator-0.21a_protect_loopframe/src/stsoundlib/YmMusic.cpp
--- 10-STYMulator-0.21a_avoid_ambiguous_else/src/stsoundlib/YmMusic.cpp	2010-04-21 19:01:44.377500997 +0200
+++ 11-STYMulator-0.21a_protect_loopframe/src/stsoundlib/YmMusic.cpp	2010-04-24 02:07:48.297625418 +0200
@@ -325,6 +325,10 @@
 		if (bLoop)
 		{
 			currentFrame = loopFrame;
+			if (currentFrame < 0)
+				currentFrame = 0;
+			else if (currentFrame >= nbFrame)
+				currentFrame = nbFrame - 1;
 		}
 		else
 		{