ipx.

1 files changed, 175 insertions, 0 deletions

diff --git a/sys/arch/i386/i386/ipx_cksum.c b/sys/arch/i386/i386/ipx_cksum.c
new file mode 100644
index 00000000000..09bc0dc224d
--- /dev/null
+++ b/sys/arch/i386/i386/ipx_cksum.c
@@ -0,0 +1,175 @@
+/*	$OpenBSD: ipx_cksum.c,v 1.1 1996/08/16 09:48:40 mickey Exp $	*/
+
+/*-
+ * Copyright (c) 1994, 1995 Charles M. Hannum.  All rights reserved.
+ * Copyright (c) 1990 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.
+ *
+ * from NetBSD: in_cksum.c	1.8	95/05/01
+ * from tahoe:	in_cksum.c	1.2	86/01/05
+ *	@(#)in_cksum.c	1.3 (Berkeley) 1/19/91
+ */
+
+#include <sys/param.h>
+#include <sys/mbuf.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 386 version.
+ */
+
+#define REDUCE          {sum = (sum & 0xffff) + (sum >> 16);}
+#define	ADDCARRY	{if (sum > 0xffff) sum -= 0xffff;}
+#define	SWAP		{sum <<= 8;}
+#define	ADVANCE(x)	{w += x; mlen -= x;}
+
+/*
+ * Thanks to gcc we don't have to guess
+ * which registers contain sum & w.
+ */
+#define	Asm	__asm __volatile
+#define ADD(n)  Asm("addl " #n "(%2),%0" : "=r" (sum) : "0" (sum), "r" (w))
+#define ADC(n)  Asm("adcl " #n "(%2),%0" : "=r" (sum) : "0" (sum), "r" (w))
+#define MOP     Asm("adcl $0,%0" :         "=r" (sum) : "0" (sum))
+#define	UNSWAP	Asm("roll $8,%0" :	   "=r" (sum) : "0" (sum))
+#define	ADDBYTE	{sum += *w; SWAP; byte_swapped ^= 1;}
+#define	ADDWORD	{sum += *(u_short *)w;}
+
+u_short
+ipx_cksum(m, len)
+	register struct mbuf *m;
+	register int len;
+{
+	register u_char *w;
+	register unsigned sum = 0;
+	register int mlen = 0;
+	int byte_swapped = 0;
+
+	for (; m && len; m = m->m_next) {
+		mlen = m->m_len;
+		if (mlen == 0)
+			continue;
+		w = mtod(m, u_char *);
+		if (len < mlen)
+			mlen = len;
+		len -= mlen;
+		if (mlen < 16)
+			goto short_mbuf;
+		/*
+		 * Force to long boundary so we do longword aligned
+		 * memory operations
+		 */
+		if ((3 & (long)w) != 0) {
+			REDUCE;
+			if ((1 & (long)w) != 0) {
+				ADDBYTE;
+				ADVANCE(1);
+			}
+			if ((2 & (long)w) != 0) {
+				ADDWORD;
+				ADVANCE(2);
+			}
+		}
+		/*
+		 * Align 4 bytes past a 16-byte cache line boundary.
+		 */
+		if ((4 & (long)w) == 0) {
+			ADD(0);
+			MOP;
+			ADVANCE(4);
+		}
+		if ((8 & (long)w) != 0) {
+			ADD(0);  ADC(4);
+			MOP;
+			ADVANCE(8);
+		}
+		/*
+		 * 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.
+			 *
+			 * We aligned the pointer above so that the out-of-
+			 * order operations will cause the next cache line to
+			 * be preloaded while we finish with the current one.
+			 */
+			ADD(12); ADC(0);  ADC(4);  ADC(8);
+			ADC(28); ADC(16); ADC(20); ADC(24);
+			MOP;
+			w += 32;
+		}
+		mlen += 32;
+		if (mlen >= 16) {
+			ADD(12); ADC(0);  ADC(4);  ADC(8);
+			MOP;
+			ADVANCE(16);
+		}
+	short_mbuf:
+		if (mlen >= 8) {
+			ADD(0);  ADC(4);
+			MOP;
+			ADVANCE(8);
+		}
+		if (mlen >= 4) {
+			ADD(0);
+			MOP;
+			ADVANCE(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);
+}
+