lu_byte is enough for those fields (maxstack < 256)

lcode.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lcode.c,v 1.1 2001/11/29 22:14:34 rieru Exp rieru $
+** $Id: lcode.c,v 1.89 2002/02/05 22:39:12 roberto Exp roberto $
 ** Code generator for Lua
 ** See Copyright Notice in lua.h
 */
@@ -176,7 +176,7 @@ void luaK_reserveregs (FuncState *fs, int n) {
   if (fs->freereg > fs->f->maxstacksize) {
     if (fs->freereg >= MAXSTACK)
       luaK_error(fs->ls, "function or expression too complex");
-    fs->f->maxstacksize = cast(short, fs->freereg);
+    fs->f->maxstacksize = cast(lu_byte, fs->freereg);
   }
 }
 

lfunc.c

@@ -1,5 +1,5 @@
 /*
-** $Id: lfunc.c,v 1.1 2001/11/29 22:14:34 rieru Exp rieru $
+** $Id: lfunc.c,v 1.53 2001/12/21 17:31:35 roberto Exp roberto $
 ** Auxiliary functions to manipulate prototypes and closures
 ** See Copyright Notice in lua.h
 */
@@ -29,7 +29,7 @@ Closure *luaF_newCclosure (lua_State *L, int nelems) {
   c->c.next = G(L)->rootcl;
   G(L)->rootcl = c;
   c->c.marked = 0;
-  c->c.nupvalues = cast(short, nelems);
+  c->c.nupvalues = cast(lu_byte, nelems);
   return c;
 }
 
@@ -40,7 +40,7 @@ Closure *luaF_newLclosure (lua_State *L, int nelems) {
   c->c.next = G(L)->rootcl;
   G(L)->rootcl = c;
   c->l.marked = 0;
-  c->l.nupvalues = cast(short, nelems);
+  c->l.nupvalues = cast(lu_byte, nelems);
   return c;
 }
 

lobject.h

@@ -1,5 +1,5 @@
 /*
-** $Id: lobject.h,v 1.1 2001/11/29 22:14:34 rieru Exp rieru $
+** $Id: lobject.h,v 1.124 2002/02/08 22:42:41 roberto Exp roberto $
 ** Type definitions for Lua objects
 ** See Copyright Notice in lua.h
 */
@@ -147,11 +147,11 @@ typedef struct Proto {
   int sizelineinfo;  /* size of `lineinfo' */
   int sizelocvars;
   int lineDefined;
-  short nupvalues;
-  short numparams;
-  short is_vararg;
-  short maxstacksize;
-  short marked;
+  lu_byte nupvalues;
+  lu_byte numparams;
+  lu_byte is_vararg;
+  lu_byte maxstacksize;
+  lu_byte marked;
 } Proto;