Add ASM optimised range_limit() for ARM, which gives a tiny performance

gain. Removed a couple of tabs.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8740 a1c6a512-1295-4272-9138-f99709370657

apps/plugins/jpeg.c

@@ -172,6 +172,16 @@ INLINE unsigned range_limit(int value)
         [v]"+r"(value)
     );
     return value;
+#elif defined(CPU_ARM)
+    asm (
+        "adds %[v], %[v], #128\n"  /* value += 128 */
+        "movmi %[v], #0       \n"  /* clip to 0 if negative result */
+        "cmp %[v], #255       \n"  /* did we exceed 255? */
+        "movgt %[v], #255     \n"  /* yes, clip to limit */
+        :
+        [v]"+r"(value)
+    );
+    return value;
 #else
     value += 128;