--- deliantra/server/utils/cfhq2xa.C	2010/03/26 00:59:22	1.9
+++ deliantra/server/utils/cfhq2xa.C	2016/11/18 05:53:42	1.15
@@ -1,23 +1,23 @@
 /*
  * This file is part of Deliantra, the Roguelike Realtime MMORPG.
- * 
- * Copyright (©) 2007 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
+ *
+ * Copyright (©) 2007,2008,2009,2010,2011,2012,2013,2014,2015,2016 Marc Alexander Lehmann / Robin Redeker / the Deliantra team
  * Copyright (©) 2003 MaxSt <maxst@hiend3d.com>
- * 
+ *
  * Deliantra is free software: you can redistribute it and/or modify it under
  * the terms of the Affero GNU General Public License as published by the
  * Free Software Foundation, either version 3 of the License, or (at your
  * option) any later version.
- * 
+ *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  * GNU General Public License for more details.
- * 
+ *
  * You should have received a copy of the Affero GNU General Public License
  * and the GNU General Public License along with this program. If not, see
  * <http://www.gnu.org/licenses/>.
- * 
+ *
  * The authors can be reached via e-mail to <support@deliantra.net>
  */
 
@@ -55,6 +55,13 @@
 # define trV   0x10
 # define trA   0x40
 
+static int32_t
+udiff (uint32_t a, uint32_t b)
+{
+  return a > b ? a - b : b - a;
+
+}
+
 static inline pixel lerp (pixel c1, int w1, pixel c2, int w2, pixel c3, int w3, int shift)
 {
 #if 0
@@ -182,10 +189,10 @@
   pixel YUV1 = RGBAtoYUVA (w1);
   pixel YUV2 = RGBAtoYUVA (w2);
 
-  return ((abs (((YUV1 >> Rshift) & Cmask) - ((YUV2 >> Rshift) & Cmask)) > trY) ||
-          (abs (((YUV1 >> Gshift) & Cmask) - ((YUV2 >> Gshift) & Cmask)) > trU) ||
-          (abs (((YUV1 >> Bshift) & Cmask) - ((YUV2 >> Bshift) & Cmask)) > trV) ||
-          (abs (((YUV1 >> Ashift) & Cmask) - ((YUV2 >> Ashift) & Cmask)) > trA) );
+  return ((udiff ((YUV1 >> Rshift) & Cmask, (YUV2 >> Rshift) & Cmask) > trY) ||
+          (udiff ((YUV1 >> Gshift) & Cmask, (YUV2 >> Gshift) & Cmask) > trU) ||
+          (udiff ((YUV1 >> Bshift) & Cmask, (YUV2 >> Bshift) & Cmask) > trV) ||
+          (udiff ((YUV1 >> Ashift) & Cmask, (YUV2 >> Ashift) & Cmask) > trA) );
 }
 
 static void