diff --git a/kernel/trunk/network/IPv4.inc b/kernel/trunk/network/IPv4.inc
index f1f7cea307..9dc4d3a43c 100644
--- a/kernel/trunk/network/IPv4.inc
+++ b/kernel/trunk/network/IPv4.inc
@@ -490,8 +490,8 @@ ipv4_input:
 
         push    eax
         mov     ax, [edx + IPv4_header.FlagsAndFragmentOffset]
-        shl     ax, 3
         xchg    al, ah
+        shl     ax, 3
         add     cx, ax
         pop     eax
         DEBUGF  DEBUG_NETWORK_VERBOSE, "IPv4_input: Total Fragment size=%u\n", ecx
@@ -1158,4 +1158,4 @@ ipv4_api:
 
         call    net_send_event
         xor     eax, eax
-        ret
+        ret
\ No newline at end of file