/* $OpenBSD: in_cksum.c,v 1.3 2004/04/07 18:24:19 mickey Exp $ */
/*
* Copyright (c) 2000 Michael Shalayeff
* All rights reserved.
*
* based on a sparc version of Zubin Dittia.
* Copyright (c) 1995 Zubin Dittia.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE AUTHOR OR HIS RELATIVES BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
* SERVICES; LOSS OF MIND, USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
* THE POSSIBILITY OF SUCH DAMAGE.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <netinet/in.h>
/*
* Checksum routine for Internet Protocol family headers.
*
* This routine is very heavily used in the network
* code and should be modified for each CPU to be as fast as possible.
*
* HPPA version.
*/
#define ADD32 asm volatile( "ldw 0x00(%1), %%r19! ldw 0x04(%1), %%r20\n\t" \
"add %0, %%r19, %0 ! addc %0, %%r20, %0\n\t" \
"ldw 0x08(%1), %%r19! ldw 0x0c(%1), %%r20\n\t" \
"addc %0, %%r19, %0 ! addc %0, %%r20, %0\n\t" \
"ldw 0x10(%1), %%r19! ldw 0x14(%1), %%r20\n\t" \
"addc %0, %%r19, %0 ! addc %0, %%r20, %0\n\t" \
"ldw 0x18(%1), %%r19! ldw 0x1c(%1), %%r20\n\t" \
"addc %0, %%r19, %0 ! addc %0, %%r20, %0\n\t" \
"ldo 0x20(%1), %1 ! addc %0, %%r0 , %0" \
: "+r" (sum), "+r" (w) :: "r20", "r19")
#define ADD16 asm volatile( "ldw 0x00(%1), %%r19! ldw 0x04(%1), %%r20\n\t" \
"add %0, %%r19, %0! addc %0, %%r20, %0\n\t" \
"ldw 0x08(%1), %%r19! ldw 0x0c(%1), %%r20\n\t" \
"addc %0, %%r19, %0! addc %0, %%r20, %0\n\t" \
"ldo 0x10(%1), %1 ! addc %0, %%r0 , %0" \
: "+r" (sum), "+r" (w) :: "r20", "r19")
#define ADDCARRY {if (sum > 0xffff) sum -= 0xffff;}
#define REDUCE {sum = (sum & 0xffff) + (sum >> 16); ADDCARRY}
#define ROL asm volatile ("shd %0, %0, 8, %0" : "+r" (sum))
#define ADDBYTE {ROL; sum += *w++; bins++; mlen--;}
#define ADDSHORT {sum += *((u_short *)w)++; mlen -= 2;}
#define ADDWORD asm volatile( "ldwm 4(%1), %%r19! add %0, %%r19, %0\n\t" \
"ldo -4(%2), %2 ! addc %0, 0, %0" \
: "+r" (sum), "+r" (w), "+r" (mlen) :: "r19")
int
in_cksum(m, len)
register struct mbuf *m;
register int len;
{
register u_int sum = 0;
register u_int bins = 0;
for (; m && len; m = m->m_next) {
register int mlen = m->m_len;
register u_char *w;
if (!mlen)
continue;
if (len < mlen)
mlen = len;
len -= mlen;
w = mtod(m, u_char *);
if (mlen > 16) {
/*
* If we are aligned on a doubleword boundary
* do 32 bit bundled operations
*/
if ((7 & (u_long)w) != 0) {
if ((1 & (u_long)w) != 0)
ADDBYTE;
if ((2 & (u_long)w) != 0)
ADDSHORT;
if ((4 & (u_long)w) != 0)
ADDWORD;
}
while ((mlen -= 32) >= 0)
ADD32;
mlen += 32;
if (mlen >= 16) {
ADD16;
mlen -= 16;
}
}
while (mlen > 0)
ADDBYTE;
}
if (bins & 1)
ROL;
REDUCE;
return (0xffff ^ sum);
}