From 95f6dc70118ea711e13de79300a8a052bbd7e0ed Mon Sep 17 00:00:00 2001
From: goldsimon <goldsimon>
Date: Wed, 6 May 2009 17:35:50 +0000
Subject: [PATCH] On little endian architectures, use LWIP_PLATFORM_HTONS (if
 defined) for SWAP_BYTES_IN_WORD to speed up checksumming.

---
 CHANGELOG                   | 4 ++++
 src/core/ipv4/inet_chksum.c | 7 +++++++
 2 files changed, 11 insertions(+)

diff --git a/CHANGELOG b/CHANGELOG
index ce0f6960..0207262d 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -99,6 +99,10 @@ HISTORY
 
   ++ Bugfixes:
 
+  2009-05-06 Simon Goldschmidt
+  * inet_chksum.c: On little endian architectures, use LWIP_PLATFORM_HTONS (if
+    defined) for SWAP_BYTES_IN_WORD to speed up checksumming.
+
   2009-05-05 Simon Goldschmidt
   * sockets.c: bug #26405: Prematurely released semaphore causes lwip_select()
     to crash
diff --git a/src/core/ipv4/inet_chksum.c b/src/core/ipv4/inet_chksum.c
index 439c9760..a30a1834 100644
--- a/src/core/ipv4/inet_chksum.c
+++ b/src/core/ipv4/inet_chksum.c
@@ -64,7 +64,14 @@
 #endif
 
 /** Like the name says... */
+#if LWIP_PLATFORM_BYTESWAP && (BYTE_ORDER == LITTLE_ENDIAN)
+/* little endian and PLATFORM_BYTESWAP defined */
+#define SWAP_BYTES_IN_WORD(w) LWIP_PLATFORM_HTONS(x)
+#else
+/* can't use htons on big endian (or PLATFORM_BYTESWAP not defined)... */
 #define SWAP_BYTES_IN_WORD(w) ((w & 0xff) << 8) | ((w & 0xff00) >> 8)
+#endif
+
 /** Split an u32_t in two u16_ts and add them up */
 #define FOLD_U32T(u)          ((u >> 16) + (u & 0x0000ffffUL))