/*
* Copyright (c) 1988, 1992, 1993
* The Regents of the University of California. All rights reserved.
*
* 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.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``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 REGENTS OR CONTRIBUTORS 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 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.
*
* @(#)in_cksum.c 8.1 (Berkeley) 6/10/93
* $Id$
*/
#include <sys/param.h>
#include <sys/mbuf.h>
#if (defined (__mcf5200__))
# define IS_COLDFIRE 1
#else
# define IS_COLDFIRE 0
#endif
#define REDUCE { sum = (sum & 0xFFFF) + (sum >> 16); if (sum > 0xFFFF) sum -= 0xFFFF; }
/*
* Motorola 68k version of Internet Protocol Checksum routine
* W. Eric Norum
* Saskatchewan Accelerator Laboratory
* August, 1998
*/
int
in_cksum(m, len)
struct mbuf *m;
int len;
{
unsigned short *w;
unsigned long sum = 0;
int mlen = 0;
int byte_swapped = 0;
union {
char c[2];
u_short s;
} s_util;
for ( ; m && len ; m = m->m_next) {
if (m->m_len == 0)
continue;
w = mtod(m, u_short *);
if (mlen == -1) {
/*
* The first byte of this mbuf is the continuation
* of a word spanning between this mbuf and the
* last mbuf.
*
* s_util.c[0] is already saved when scanning previous
* mbuf.
*/
s_util.c[1] = *(char *)w;
sum += s_util.s;
w = (u_short *)((char *)w + 1);
mlen = m->m_len - 1;
len--;
} else
mlen = m->m_len;
if (len < mlen)
mlen = len;
len -= mlen;
/*
* Force to longword boundary.
*/
if (3 & (int)w) {
REDUCE;
if ((1 & (int) w) && (mlen > 0)) {
sum <<= 8;
s_util.c[0] = *(u_char *)w;
w = (u_short *)((char *)w + 1);
mlen--;
byte_swapped = 1;
}
if ((2 & (int) w) && (mlen >= 2)) {
sum += *w++;
mlen -= 2;
}
}
/*
* Sum all the longwords in the buffer.
* See RFC 1071 -- Computing the Internet Checksum.
* It should work for all 68k family members.
*/
{
unsigned long tcnt = mlen, t1;
__asm__ volatile (
"movel %2,%3\n\t"
"lsrl #6,%2 | count/64 = # loop traversals\n\t"
"andl #0x3c,%3 | Then find fractions of a chunk\n\t"
"negl %3\n\t | Each long uses 4 instruction bytes\n\t"
#if IS_COLDFIRE
"addql #1,%2 | Clear X (extended carry flag)\n\t"
"subql #1,%2 | \n\t"
#else
"andi #0xf,%%cc | Clear X (extended carry flag)\n\t"
#endif
"jmp %%pc@(lcsum2_lbl-.-2:b,%3) | Jump into loop\n"
"lcsum1_lbl: | Begin inner loop...\n\t"
"movel %1@+,%3 | 0: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 1: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 2: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 3: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 4: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 5: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 6: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 7: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 8: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | 9: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | A: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | B: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | C: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | D: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | E: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n\t"
"movel %1@+,%3 | F: Fetch 32-bit word\n\t"
"addxl %3,%0 | Add word + previous carry\n"
"lcsum2_lbl: | End of unrolled loop\n\t"
#if IS_COLDFIRE
"moveq #0,%3 | Add in last carry\n\t"
"addxl %3,%0 |\n\t"
"subql #1,%2 | Update loop count\n\t"
"bplb lcsum1_lbl | Loop (with X clear) if not done\n\t"
"movel #0xffff,%2 | Get word mask\n\t"
"movel %0,%3 | Fold 32 bit sum to 16 bits\n\t"
"swap %3 |\n\t"
"andl %2,%0 | Mask to 16-bit sum\n\t"
"andl %2,%3 | Mask to 16-bit sum\n\t"
"addl %3,%0 |\n\t"
"movel %0,%3 | Add in last carry\n\t"
"swap %3 |\n\t"
"addl %3,%0 |\n\t"
"andl %2,%0 | Mask to 16-bit sum\n\t"
#else
"dbf %2,lcsum1_lbl | (NB- dbf doesn't affect X)\n\t"
"movel %0,%3 | Fold 32 bit sum to 16 bits\n\t"
"swap %3 | (NB- swap doesn't affect X)\n\t"
"addxw %3,%0 |\n\t"
"moveq #0,%3 | Add in last carry\n\t"
"addxw %3,%0 |\n\t"
"andl #0xffff,%0 | Mask to 16-bit sum\n"
#endif
:
"=d" (sum), "=a" (w), "=d" (tcnt) , "=d" (t1) :
"0" (sum), "1" (w), "2" (tcnt) :
"cc", "memory");
}
mlen &= 3;
/*
* Soak up the last 1, 2 or 3 bytes
*/
while ((mlen -= 2) >= 0)
sum += *w++;
if (byte_swapped) {
REDUCE;
sum <<= 8;
byte_swapped = 0;
if (mlen == -1) {
s_util.c[1] = *(char *)w;
sum += s_util.s;
mlen = 0;
} else
mlen = -1;
} else if (mlen == -1)
s_util.c[0] = *(char *)w;
}
if (len)
sum = 0xDEAD;
if (mlen == -1) {
/* The last mbuf has odd # of bytes. Follow the
standard (the odd byte may be shifted left by 8 bits
or not as determined by endian-ness of the machine) */
s_util.c[1] = 0;
sum += s_util.s;
}
REDUCE;
return (~sum & 0xffff);
}
