2 files changed, 25 insertions, 12 deletions
diff --git a/miasm2/expression/expression.py b/miasm2/expression/expression.py
index 581dc8dc..f8af52d9 100644
--- a/miasm2/expression/expression.py
+++ b/miasm2/expression/expression.py
@@ -380,6 +380,8 @@ class ExprInt(Expr):
             if size is not None and num.size != size:
                 raise RuntimeError("size must match modint size")
         elif size is not None:
+            if size not in mod_size2uint:
+                define_uint(size)
             self.__arg = mod_size2uint[size](num)
             self.__size = self.arg.size
         else:
diff --git a/miasm2/expression/modint.py b/miasm2/expression/modint.py
index 76896eb9..a801c948 100644
--- a/miasm2/expression/modint.py
+++ b/miasm2/expression/modint.py
@@ -198,25 +198,36 @@ mod_size2int = {}
 mod_uint2size = {}
 mod_int2size = {}
 
+def define_int(size):
+    """Build the 'modint' instance corresponding to size @size"""
+    global mod_size2int, mod_int2size
+
+    name = 'int%d' % size
+    cls = type(name, (modint,), {"size": size, "limit": 1 << size})
+    globals()[name] = cls
+    mod_size2int[size] = cls
+    mod_int2size[cls] = size
+    return cls
+
+def define_uint(size):
+    """Build the 'moduint' instance corresponding to size @size"""
+    global mod_size2uint, mod_uint2size
+
+    name = 'uint%d' % size
+    cls = type(name, (moduint,), {"size": size, "limit": 1 << size})
+    globals()[name] = cls
+    mod_size2uint[size] = cls
+    mod_uint2size[cls] = size
+    return cls
 
 def define_common_int():
     "Define common int: ExprInt1, ExprInt2, .."
-    global mod_size2int, mod_int2size, mod_size2uint, mod_uint2size
-
     common_int = xrange(1, 257)
 
     for i in common_int:
-        name = 'uint%d' % i
-        c = type(name, (moduint,), {"size": i, "limit": 1 << i})
-        globals()[name] = c
-        mod_size2uint[i] = c
-        mod_uint2size[c] = i
+        define_int(i)
 
     for i in common_int:
-        name = 'int%d' % i
-        c = type(name, (modint,), {"size": i, "limit": 1 << i})
-        globals()[name] = c
-        mod_size2int[i] = c
-        mod_int2size[c] = i
+        define_uint(i)
 
 define_common_int()