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

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