text: /*
   * include/asm-v850/checksum.h -- Checksum ops
   *
   *  Copyright (C) 2001,2005  NEC Corporation
   *  Copyright (C) 2001,2005  Miles Bader <miles@gnu.org>
   *
   * This file is subject to the terms and conditions of the GNU General
   * Public License.  See the file COPYING in the main directory of this
   * archive for more details.
   *
   * Written by Miles Bader <miles@gnu.org>
   */
  
  #ifndef __V850_CHECKSUM_H__
  #define __V850_CHECKSUM_H__
  
  /*
   * computes the checksum of a memory block at buff, length len,
   * and adds in "sum" (32-bit)
   *
   * returns a 32-bit number suitable for feeding into itself
   * or csum_tcpudp_magic
   *
   * this function must be called with even lengths, except
   * for the last fragment, which may be odd
   *
   * it's best to have buff aligned on a 32-bit boundary
   */
  extern __wsum csum_partial(const void *buff, int len, __wsum sum);
  
  /*
   * the same as csum_partial, but copies from src while it
   * checksums
   *
   * here even more important to align src and dst on a 32-bit (or even
   * better 64-bit) boundary
   */
  extern __wsum csum_partial_copy_nocheck(const void *src,
  				   void *dst, int len, __wsum sum);
  
  
  /*
   * the same as csum_partial_copy, but copies from user space.
   *
   * here even more important to align src and dst on a 32-bit (or even
   * better 64-bit) boundary
   */
  extern __wsum csum_partial_copy_from_user (const void *src,
  					     void *dst,
  					     int len, __wsum sum,
  					     int *csum_err);
  
  __sum16 ip_fast_csum(const void *iph, unsigned int ihl);
  
  /*
   *	Fold a partial checksum
   */
  static inline __sum16 csum_fold (__wsum sum)
  {
  	unsigned int result;
  	/*
  			        %0		%1
  	      hsw %1, %0	H     L		L     H
  	      add %1, %0	H     L		H+L+C H+L
  	*/
  	asm ("hsw %1, %0; add %1, %0" : "=&r" (result) : "r" (sum));
  	return (__force __sum16)(~result >> 16);
  }
  
  
  /*
   * computes the checksum of the TCP/UDP pseudo-header
   * returns a 16-bit checksum, already complemented
   */
  static inline __wsum
  csum_tcpudp_nofold (__be32 saddr, __be32 daddr,
  		    unsigned short len,
  		    unsigned short proto, __wsum sum)
  {
  	int __carry;
  	__asm__ ("add %2, %0;"
  		 "setf c, %1;"
  		 "add %1, %0;"
  		 "add %3, %0;"
  		 "setf c, %1;"
  		 "add %1, %0;"
  		 "add %4, %0;"
  		 "setf c, %1;"
  		 "add %1, %0"
  		 : "=&r" (sum), "=&r" (__carry)
  		 : "r" (daddr), "r" (saddr),
  		 "r" ((len + proto) << 8),
  		 "0" (sum));
  	return sum;
  }
  
  static inline __sum16
  csum_tcpudp_magic (__be32 saddr, __be32 daddr,
  		   unsigned short len,
  		   unsigned short proto, __wsum sum)
  {
  	return csum_fold (csum_tcpudp_nofold (saddr, daddr, len, proto, sum));
  }
  
  /*
   * this routine is used for miscellaneous IP-like checksums, mainly
   * in icmp.c
   */
  extern __sum16 ip_compute_csum(const void *buff, int len);
  
  
  #endif /* __V850_CHECKSUM_H__ */
  