[update] documentation

doc/tutorial/tutorial.tex

@@ -146,6 +146,8 @@ The board BLUE and GREEN leds should be blinking (those leds are near the user a
 
 \newpage
 \section{Notes}
+
+\subsection{Disassembling THUMB code in GDB}
 \paragraph{}
 By default, the disassemble command in GDB operates in ARM mode. The programs running on CORTEX-M3
 are compiled in THUMB mode. To correctly disassemble them under GDB, uses an odd address. For instance,