diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/disassembly/dsf/AbstractDisassemblyBackend.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/disassembly/dsf/AbstractDisassemblyBackend.java
index ff50ac6e3db..4df56b623e4 100644
--- a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/disassembly/dsf/AbstractDisassemblyBackend.java
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/disassembly/dsf/AbstractDisassemblyBackend.java
@@ -85,6 +85,6 @@ public abstract class AbstractDisassemblyBackend implements IDisassemblyBackend
 	
 	@Override
 	public BigInteger getLastKnownAddress() {
-		return BigInteger.valueOf(-1);
+		return UNKNOWN_ADDRESS;
 	}
 }
diff --git a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/disassembly/dsf/IDisassemblyBackend.java b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/disassembly/dsf/IDisassemblyBackend.java
index d80e2a97d71..9de19982d63 100644
--- a/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/disassembly/dsf/IDisassemblyBackend.java
+++ b/debug/org.eclipse.cdt.debug.ui/src/org/eclipse/cdt/debug/internal/ui/disassembly/dsf/IDisassemblyBackend.java
@@ -201,14 +201,15 @@ public interface IDisassemblyBackend {
 	void updateExtendedPCAnnotation(IAnnotationModel model);
 	
 	/**
-	 * Returns true if this backend can disassemble instructions.
-	 * @return true if backend can perform disassemble 
+	 * This is a test for the current context.
+	 * 
+	 * @return true if backend can perform disassemble, otherwise false 
 	 */
 	boolean canDisassemble();
 	
 	/**
-	 * Returns the last know address, this API will be call if the selected
-	 * debug context is not a stackframe.
+	 * Returns the last known address, this API will be call if the selected debug context is not a stackframe.
+	 * 
 	 * @return the last know address, -1 if unknown
 	 */
 	BigInteger getLastKnownAddress();