diff --git a/lua-engine.cpp b/lua-engine.cpp
index 55f314f2..b06977b6 100644
--- a/lua-engine.cpp
+++ b/lua-engine.cpp
@@ -1129,14 +1129,14 @@ DEFINE_LUA_FUNCTION(addressof, "table_or_function")
 	return 1;
 }
 
-// the following bit operations are ported from LuaBitOp 1.0.1,
+// the following bit operations are ported from LuaBitOp 1.0.12
 // because it can handle the sign bit (bit 31) correctly.
 
 /*
-** Lua BitOp -- a bit operations library for Lua 5.1.
+** Lua BitOp -- a bit operations library for Lua 5.1/5.2.
 ** http://bitop.luajit.org/
 **
-** Copyright (C) 2008-2009 Mike Pall. All rights reserved.
+** Copyright (C) 2008-2012 Mike Pall. All rights reserved.
 **
 ** Permission is hereby granted, free of charge, to any person obtaining
 ** a copy of this software and associated documentation files (the
@@ -1186,7 +1186,11 @@ static UBits barg(lua_State *L, int idx)
 {
   BitNum bn;
   UBits b;
+#if LUA_VERSION_NUM < 502
   bn.n = lua_tonumber(L, idx);
+#else
+  bn.n = luaL_checknumber(L, idx);
+#endif
 #if defined(LUA_NUMBER_DOUBLE)
   bn.n += 6755399441055744.0;  /* 2^52+2^51 */
 #ifdef SWAPPED_DOUBLE
@@ -1206,8 +1210,11 @@ static UBits barg(lua_State *L, int idx)
 #else
 #error "Unknown number type, check LUA_NUMBER_* in luaconf.h"
 #endif
-  if (b == 0 && !lua_isnumber(L, idx))
+#if LUA_VERSION_NUM < 502
+  if (b == 0 && !lua_isnumber(L, idx)) {
     luaL_typerror(L, idx, "number");
+  }
+#endif
   return b;
 }
 
@@ -1301,6 +1308,11 @@ bool luabitop_validate(lua_State *L) // originally named as luaopen_bit
     luaL_error(L, "bit library self-test failed (%s)", msg);
     return false;
   }
+#if LUA_VERSION_NUM < 502
+  luaL_register(L, "bit", bit_funcs);
+#else
+  luaL_newlib(L, bit_funcs);
+#endif
   return true;
 }