/* *  arch/s390/lib/checksum.c *    S390 fast network checksum routines * *  S390 version *    Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation *    Author(s): Ulrich Hild        (first version), *               Martin Schwidefsky (schwidefsky@de.ibm.com), *               Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com), * * This file contains network checksum routines */ #include <linux/string.h>#include <linux/types.h>#include <asm/uaccess.h>#include <asm/byteorder.h>#include <asm/checksum.h>/* * computes a partial checksum, e.g. for TCP/UDP fragments */unsigned intcsum_partial (const unsigned char *buff, int len, unsigned int sum){	register_pair rp;	  /*	   * Experiments with ethernet and slip connections show that buff	   * is aligned on either a 2-byte or 4-byte boundary.	   */	rp.subreg.even = (unsigned long) buff;	rp.subreg.odd = (unsigned long) len;        __asm__ __volatile__ (                "0:  cksm %0,%1\n"    /* do checksum on longs */                "    jo   0b\n"                : "+&d" (sum), "+&a" (rp) : : "cc" );        return sum;}/* *	Fold a partial checksum without adding pseudo headers */unsigned short csum_fold(unsigned int sum){	register_pair rp;	__asm__ __volatile__ (		"    slr  %N1,%N1\n" /* %0 = H L */		"    lr   %1,%0\n"   /* %0 = H L, %1 = H L 0 0 */		"    srdl %1,16\n"   /* %0 = H L, %1 = 0 H L 0 */		"    alr  %1,%N1\n"  /* %0 = H L, %1 = L H L 0 */		"    alr  %0,%1\n"   /* %0 = H+L+C L+H */		"    srl  %0,16\n"   /* %0 = H+L+C */		: "+&d" (sum), "=d" (rp) : : "cc" );	return ((unsigned short) ~sum);}