arch/cris/include/arch-v10/arch/checksum.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _CRIS_ARCH_CHECKSUM_H
   3 #define _CRIS_ARCH_CHECKSUM_H
   4
   5 /* Checksum some values used in TCP/UDP headers.
   6  *
   7  * The gain by doing this in asm is that C will not generate carry-additions
   8  * for the 32-bit components of the checksum, so otherwise we would have had
   9  * to split all of those into 16-bit components, then add.
  10  */
  11
  12 static inline __wsum
  13 csum_tcpudp_nofold(__be32 saddr, __be32 daddr, __u32 len,
  14                    __u8 proto, __wsum sum)
  15 {
  16         __wsum res;
  17         __asm__ ("add.d %2, %0\n\t"
  18                  "ax\n\t"
  19                  "add.d %3, %0\n\t"
  20                  "ax\n\t"
  21                  "add.d %4, %0\n\t"
  22                  "ax\n\t"
  23                  "addq 0, %0\n"
  24         : "=r" (res)
  25         : "0" (sum), "r" (daddr), "r" (saddr), "r" ((len + proto) << 8));
  26
  27         return res;
  28 }
  29
  30 #endif