diff --git a/doc/nes.sgml b/doc/nes.sgml
index a3ac79a68..d4e6a3fac 100644
--- a/doc/nes.sgml
+++ b/doc/nes.sgml
@@ -69,6 +69,7 @@ Programs containing NES specific code may use the <tt/nes.h/ header file.
 
 <itemize>
 <item>waitvblank
+<item>get_tv
 </itemize>
 
 
diff --git a/include/nes.h b/include/nes.h
index 7a2f3e176..48c5418e0 100644
--- a/include/nes.h
+++ b/include/nes.h
@@ -83,11 +83,19 @@
 #define COLOR_LIGHTBLUE      	0x0E
 #define COLOR_GRAY3  	       	0x0F
 
+/* Return codes of get_tv */
+#define TV_NTSC         0
+#define TV_PAL          1
+#define TV_OTHER        2
+
 
 
 void __fastcall__ waitvblank (void);
 /* Wait for the vertical blanking */
 
+unsigned char __fastcall__ get_tv (void);
+/* Return the video mode the machine is using. */
+
 
 
 /* End of nes.h */