diff -up src-orig/arm_instructions.cpp src/arm_instructions.cpp
--- src-orig/arm_instructions.cpp	2010-04-18 02:11:20.000000000 +0900
+++ src/arm_instructions.cpp	2010-06-04 18:45:54.625000000 +0900
@@ -6376,6 +6376,12 @@ TEMPLATE static u32 FASTCALL  OP_STMDB_W
 	u32 c = 0, b;
 	u32 start = cpu->R[REG_POS(i,16)];
 	
+#ifdef HAVE_LUA
+	if (REG_POS(i,16) == 13 && BIT_N(i, 14) && PROCNUM == 0) {
+		CallRegisteredLuaFunctions(LUACALL_ENTERFUNCTION);
+	}
+#endif
+	
 	for(b=0; b<16; ++b)
 	{
 		if(BIT_N(i, 15-b))
diff -up src-orig/lua-engine.cpp src/lua-engine.cpp
--- src-orig/lua-engine.cpp	2010-02-04 15:22:54.000000000 +0900
+++ src/lua-engine.cpp	2010-06-04 18:20:34.328125000 +0900
@@ -154,6 +154,8 @@ static const char* luaCallIDStrings [] =
 	"CALL_HOTKEY_14",
 	"CALL_HOTKEY_15",
 	"CALL_HOTKEY_16",
+	
+	"CALL_ENTERFUNCTION",
 };
 static const int _makeSureWeHaveTheRightNumberOfStrings [sizeof(luaCallIDStrings)/sizeof(*luaCallIDStrings) == LUACALL_COUNT ? 1 : 0];
 
@@ -393,6 +395,18 @@ DEFINE_LUA_FUNCTION(input_registerhotkey
 	}
 }
 
+DEFINE_LUA_FUNCTION(emu_registerenterfunc, "func")
+{
+	if (!lua_isnil(L,1))
+		luaL_checktype(L, 1, LUA_TFUNCTION);
+	lua_settop(L,1);
+	lua_getfield(L, LUA_REGISTRYINDEX, luaCallIDStrings[LUACALL_ENTERFUNCTION]);
+	lua_insert(L,1);
+	lua_setfield(L, LUA_REGISTRYINDEX, luaCallIDStrings[LUACALL_ENTERFUNCTION]);
+	StopScriptIfFinished(luaStateToUIDMap[L->l_G->mainthread]);
+	return 1;
+}
+
 static int doPopup(lua_State* L, const char* deftype, const char* deficon)
 {
 	const char* str = toCString(L,1);
@@ -4126,6 +4140,7 @@ static const struct luaL_reg emulib [] =
 	{"reset", emu_reset},
 	// alternative names
 //	{"openrom", emu_loadrom},
+	{"registerenterfunc", emu_registerenterfunc},
 	{NULL, NULL}
 };
 static const struct luaL_reg guilib [] =
diff -up src-orig/lua-engine.h src/lua-engine.h
--- src-orig/lua-engine.h	2009-10-17 00:46:36.000000000 +0900
+++ src/lua-engine.h	2010-06-04 17:16:47.296875000 +0900
@@ -37,6 +37,8 @@ enum LuaCallID
 	LUACALL_SCRIPT_HOTKEY_15,
 	LUACALL_SCRIPT_HOTKEY_16,
 
+	LUACALL_ENTERFUNCTION,
+
 	LUACALL_COUNT
 };
 void CallRegisteredLuaFunctions(LuaCallID calltype);
diff -up src-orig/thumb_instructions.cpp src/thumb_instructions.cpp
--- src-orig/thumb_instructions.cpp	2010-04-18 20:51:46.000000000 +0900
+++ src/thumb_instructions.cpp	2010-06-04 18:45:39.250000000 +0900
@@ -869,6 +869,11 @@ TEMPLATE static  u32 FASTCALL OP_PUSH_LR
 	u32 adr = cpu->R[13] - 4;
 	u32 c = 0, j;
 	
+#ifdef HAVE_LUA
+	if (PROCNUM == 0) {
+		CallRegisteredLuaFunctions(LUACALL_ENTERFUNCTION);
+	}
+#endif
 	WRITE32(cpu->mem_if->data, adr, cpu->R[14]);
 	c += MMU_memAccessCycles<PROCNUM,32,MMU_AD_WRITE>(adr);
 	adr -= 4;