--- a/th_string.c	Thu Dec 26 05:49:49 2019 +0200
+++ b/th_string.c	Thu Dec 26 06:33:35 2019 +0200
@@ -984,30 +984,30 @@
     int len;
     *value = 0;
 
-    for (len = 0; *p && len < 6; p++, len++)
+    for (len = 0; *p && len < 6 * 2; p++, len++)
     {
         if (*p >= '0' && *p <= '9')
         {
-            (*value) *= 16;
-            (*value) += (*p - '0');
+            (*value) <<= 4;
+            (*value) |= (*p - '0');
         }
         else
         if (*p >= 'A' && *p <= 'F')
         {
-            (*value) *= 16;
-            (*value) += (*p - 'A') + 10;
+            (*value) <<= 4;
+            (*value) |= (*p - 'A') + 10;
         }
         else
         if (*p >= 'a' && *p <= 'f')
         {
-            (*value) *= 16;
-            (*value) += (*p - 'a') + 10;
+            (*value) <<= 4;
+            (*value) |= (*p - 'a') + 10;
         }
         else
             return FALSE;
     }
 
-    return (len == 6);
+    return (len == 6 * 2);
 }