diff -r 1f466354a85b Lib/sre_compile.py
--- a/Lib/sre_compile.py	Mon Oct 21 09:08:39 2013 +0200
+++ b/Lib/sre_compile.py	Mon Oct 21 14:18:57 2013 +0300
@@ -339,7 +339,7 @@
     else:
         code = 'I'
     # Convert block indices to byte array of 256 bytes
-    mapping = array.array('b', mapping).tobytes()
+    mapping = array.array('B', mapping).tobytes()
     # Convert byte array to word array
     mapping = array.array(code, mapping)
     assert mapping.itemsize == _sre.CODESIZE
diff -r 1f466354a85b Lib/test/test_re.py
--- a/Lib/test/test_re.py	Mon Oct 21 09:08:39 2013 +0200
+++ b/Lib/test/test_re.py	Mon Oct 21 14:18:57 2013 +0300
@@ -482,6 +482,9 @@
                                   "\u2222").group(1), "\u2222")
         self.assertEqual(re.match("([\u2222\u2223])",
                                   "\u2222", re.UNICODE).group(1), "\u2222")
+        r = '[%s]' % ''.join(map(chr, range(256, 2**16, 255)))
+        self.assertEqual(re.match(r,
+                                  "\uff01", re.UNICODE).group(), "\uff01")
 
     def test_big_codesize(self):
         # Issue #1160
diff -r 1f466354a85b Modules/_sre.c
--- a/Modules/_sre.c	Mon Oct 21 09:08:39 2013 +0200
+++ b/Modules/_sre.c	Mon Oct 21 14:18:57 2013 +0300
@@ -457,7 +457,7 @@
                 /* !(c & ~N) == (c < N+1) for any unsigned c, this avoids
                  * warnings when c's type supports only numbers < N+1 */
                 if (!(ch & ~65535))
-                    block = ((char*)set)[ch >> 8];
+                    block = ((unsigned char*)set)[ch >> 8];
                 else
                     block = -1;
                 set += 64;