diff --git a/stix/kernel/Apex.st b/stix/kernel/Apex.st
index fccb956..e038ad8 100644
--- a/stix/kernel/Apex.st
+++ b/stix/kernel/Apex.st
@@ -219,13 +219,10 @@
 	## -------------------------------------------------------
 	## -------------------------------------------------------
 
-	#method(#class) primitiveFailed
-	{
-		## TODO: implement this
-		## PrimitiveFailureError signal.
-		self dump.
-		'primitive failed' dump.
-	}
+	## #method(#class) primitiveFailed
+	## {
+	## 	this method will be added after Exception class has been defined.
+	## }
 
 	#method primitiveFailed
 	{
diff --git a/stix/kernel/Context.st b/stix/kernel/Context.st
index a5335b4..e25426d 100644
--- a/stix/kernel/Context.st
+++ b/stix/kernel/Context.st
@@ -390,3 +390,17 @@ Processor activeProcess terminate.
 		self signal: 'no such message'.
 	}
 }
+
+
+#extend Apex
+{
+	#method(#class) primitiveFailed
+	{
+		## TODO: implement this
+		## PrimitiveFailureError signal.
+		self dump.
+		##'primitive failed' dump.
+# TODO: define a specialized exception class for primitive failure and use it.
+		Exception signal: 'PRIMITIVE FAILED...'.
+	}
+}
diff --git a/stix/kernel/test-011.st b/stix/kernel/test-011.st
index 6f88124..e9337d1 100644
--- a/stix/kernel/test-011.st
+++ b/stix/kernel/test-011.st
@@ -168,6 +168,10 @@
 	##	self test12.
 
 		##100 timesRepeat: ['>>>>> END OF MAIN' dump].
+
+		## the following line(return:to:) must cause primitive failure...
+		##[ Processor return: 10 to: 20. ] on: Exception do: [:ex | ex messageText dump].
+
 		'>>>>> END OF MAIN' dump.
 	}
 }