diff options
Diffstat (limited to 'sys/arch/vax/vax/in_cksum.c')
| -rw-r--r-- | sys/arch/vax/vax/in_cksum.c | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/sys/arch/vax/vax/in_cksum.c b/sys/arch/vax/vax/in_cksum.c new file mode 100644 index 00000000000..fa336ba344a --- /dev/null +++ b/sys/arch/vax/vax/in_cksum.c @@ -0,0 +1,152 @@ +/* $NetBSD: in_cksum.c,v 1.2 1996/04/08 18:32:38 ragge Exp $ */ + +/* + * 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 + */ + +#include <sys/param.h> +#include <sys/mbuf.h> +#include <sys/systm.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. + * + * This implementation is VAX version. + */ + +#define REDUCE {sum = (sum & 0xffff) + (sum >> 16);} +#define ADDCARRY {if (sum > 0xffff) sum -= 0xffff;} +#define ADVANCE(n) {w += n; mlen -= n;} +#define SWAP {sum <<= 8;} /* depends on recent REDUCE */ + +#define Asm __asm __volatile +#define ADDL Asm("addl2 (%2)+,%0" : "=r" (sum) : "0" (sum), "r" (w)) +#define ADWC Asm("adwc (%2)+,%0" : "=r" (sum) : "0" (sum), "r" (w)) +#define ADDC Asm("adwc $0,%0" : "=r" (sum) : "0" (sum)) +#define UNSWAP Asm("rotl $8,%0,%0" : "=r" (sum) : "0" (sum)) +#define ADDBYTE {sum += *w; SWAP; byte_swapped ^= 1;} +#define ADDWORD {sum += *(u_short *)w;} + +int +in_cksum(m, len) + register struct mbuf *m; + register int len; +{ + register u_char *w; + register u_int sum = 0; + register int mlen = 0; + int byte_swapped = 0; + + for (;m && len; m = m->m_next) { + if ((mlen = m->m_len) == 0) + continue; + w = mtod(m, u_char *); + if (len < mlen) + mlen = len; + len -= mlen; + if (mlen < 16) + goto short_mbuf; + /* + * Ensure that we're aligned on a word boundary here so + * that we can do 32 bit operations below. + */ + if ((3 & (long)w) != 0) { + REDUCE; + if ((1 & (long)w) != 0) { + ADDBYTE; + ADVANCE(1); + } + if ((2 & (long)w) != 0) { + ADDWORD; + ADVANCE(2); + } + } + /* + * Do as much of the checksum as possible 32 bits at at time. + * In fact, this loop is unrolled to make overhead from + * branches &c small. + */ + while ((mlen -= 32) >= 0) { + /* + * Add with carry 16 words and fold in the last carry + * by adding a 0 with carry. + */ + ADDL; ADWC; ADWC; ADWC; + ADWC; ADWC; ADWC; ADWC; + ADDC; + } + mlen += 32; + if (mlen >= 16) { + ADDL; ADWC; ADWC; ADWC; + ADDC; + mlen -= 16; + } + short_mbuf: + if (mlen >= 8) { + ADDL; ADWC; + ADDC; + mlen -= 8; + } + if (mlen >= 4) { + ADDL; + ADDC; + mlen -= 4; + } + if (mlen > 0) { + REDUCE; + if (mlen >= 2) { + ADDWORD; + ADVANCE(2); + } + if (mlen >= 1) { + ADDBYTE; + } + } + } + + if (len) + printf("cksum: out of data\n"); + if (byte_swapped) { + UNSWAP; + } + REDUCE; + ADDCARRY; + return (sum ^ 0xffff); +} + |