The following are diffs from an slightly earlier version of the 4.3BSD
Excelan driver found in /sys/vaxif.  The work was done by:

	Kenichi Katsumi
	Engineering Computing Management Division.
	SONY/TEKTRONIX Corp.
	...kddlab!muse!katsumi

*** if_ex.c	Fri Oct 14 17:06:14 1988
--- /sys/vaxif/if_ex.c	Tue Sep 27 17:16:42 1988
***************
*** 1,9 ****
! /*
!  * Copyright (c) 1982, 1986 Regents of the University of California.
   * All rights reserved.  The Berkeley software License Agreement
   * specifies the terms and conditions for redistribution.
   *
!  *	@(#)if_ex.c	7.1 (Berkeley) 6/5/86
   */
  
  
--- 1,8 ----
! /* Copyright (c) 1982, 1986 Regents of the University of California.
   * All rights reserved.  The Berkeley software License Agreement
   * specifies the terms and conditions for redistribution.
   *
!  *	@(#)if_ex.c	7.2 (Berkeley) 10/13/86
   */
  
  
***************
*** 17,63 ****
   *	Excelan Inc.
   */
  
! #include "../machine/pte.h"
  
  #include "param.h"
! #include "systm.h"
  #include "mbuf.h"
- #include "buf.h"
  #include "protosw.h"
  #include "socket.h"
- #include "vmmac.h"
  #include "ioctl.h"
  #include "errno.h"
  
  #include "../net/if.h"
  #include "../net/netisr.h"
  #include "../net/route.h"
  
- #ifdef	INET
- #include "../netinet/in.h"
  #include "../netinet/in_systm.h"
  #include "../netinet/in_var.h"
  #include "../netinet/ip.h"
  #include "../netinet/if_ether.h"
- #endif
- 
- #ifdef NS
  #include "../netns/ns.h"
  #include "../netns/ns_if.h"
- #endif
  
! #include "../vax/cpu.h"
! #include "../vax/mtpr.h"
! #include "if_exreg.h"
! #include "if_uba.h"
! #include "../vaxuba/ubareg.h"
! #include "../vaxuba/ubavar.h"
  
  #define DEBUG			/* check for "impossible" events */
  
  #define	NH2X 4			/* a sufficient number is critical */
  #define	NX2H 4			/* this is pretty arbitrary */
! #define	EXWATCHINTVL 10		/* call exwatch() every 10 seconds */
  
  int	exprobe(), exattach(), excdint();
  struct	uba_device *exinfo[NEX];
--- 16,66 ----
   *	Excelan Inc.
   */
  
! /*
!  * Modification from Berkeley 4.3BSD
!  *	for PDP11/44 2.10BSD
!  *
!  *	Kenichi Katsumi
!  *	SONY/TEKTRONIX Corp.
!  *				88/09/20
!  */
  
  #include "param.h"
! #include "../machine/seg.h"
! 
! #include "short_names.h"
  #include "mbuf.h"
  #include "protosw.h"
  #include "socket.h"
  #include "ioctl.h"
  #include "errno.h"
  
+ #ifdef BSD2_10
+ # include "buf.h"
+ #endif
+ 
+ #include "pdpuba/ubavar.h"
+ 
  #include "../net/if.h"
  #include "../net/netisr.h"
  #include "../net/route.h"
  
  #include "../netinet/in_systm.h"
+ #include "../netinet/in.h"
  #include "../netinet/in_var.h"
  #include "../netinet/ip.h"
  #include "../netinet/if_ether.h"
  #include "../netns/ns.h"
  #include "../netns/ns_if.h"
  
! #include "../vaxif/if_uba.h"
! #include "../vaxif/if_exreg.h"
  
  #define DEBUG			/* check for "impossible" events */
  
  #define	NH2X 4			/* a sufficient number is critical */
  #define	NX2H 4			/* this is pretty arbitrary */
! #define	EXWATCHINTVL 60		/* call exwatch() every 60 seconds */
  
  int	exprobe(), exattach(), excdint();
  struct	uba_device *exinfo[NEX];
***************
*** 94,102 ****
  #define EX_SETADDR	(1<<3)		/* physaddr has been changed */
  	struct	ex_msg *xs_h2xnext;	/* host pointer to request queue */
  	struct	ex_msg *xs_x2hnext;	/* host pointer to reply queue */
! 	int	xs_ubaddr;		/* map info for structs below */
! #define	UNIADDR(x)	((u_long)(x)&0x3FFFF)
! #define	P_UNIADDR(x)	((u_long)(x)&0x3FFF0)
  	/* the following structures are always mapped in */
  	u_short	xs_h2xhdr;		/* EXOS's request queue header */
  	u_short	xs_x2hhdr;		/* EXOS's reply queue header */
--- 97,105 ----
  #define EX_SETADDR	(1<<3)		/* physaddr has been changed */
  	struct	ex_msg *xs_h2xnext;	/* host pointer to request queue */
  	struct	ex_msg *xs_x2hnext;	/* host pointer to reply queue */
! 	ubadr_t	xs_ubaddr;		/* map info for structs below */
! #define	UNIADDR(x)	((u_long)(x)&0x3FFFFL)
! #define	P_UNIADDR(x)	((u_long)(x)&0x3FFF0L)
  	/* the following structures are always mapped in */
  	u_short	xs_h2xhdr;		/* EXOS's request queue header */
  	u_short	xs_x2hhdr;		/* EXOS's reply queue header */
***************
*** 105,111 ****
  	struct	confmsg xs_cm;		/* configuration message */
  	struct	stat_array xs_xsa;	/* EXOS writes stats here */
  	/* end mapped area */
! #define	INCORE_BASE(p)	((caddr_t)((u_long)(&(p)->xs_h2xhdr) & 0xFFFFFFF0))
  #define	RVAL_OFF(unit, n) \
  	((caddr_t)(&(ex_softc[unit].n)) - INCORE_BASE(&ex_softc[unit]))
  #define	LVAL_OFF(unit, n) \
--- 108,114 ----
  	struct	confmsg xs_cm;		/* configuration message */
  	struct	stat_array xs_xsa;	/* EXOS writes stats here */
  	/* end mapped area */
! #define	INCORE_BASE(p)	((caddr_t)((u_long)(&(p)->xs_h2xhdr) & 0xFFFFFFF0L))
  #define	RVAL_OFF(unit, n) \
  	((caddr_t)(&(ex_softc[unit].n)) - INCORE_BASE(&ex_softc[unit]))
  #define	LVAL_OFF(unit, n) \
***************
*** 142,148 ****
  	 * We program the EXOS interrupt vector, like dmf device.
  	 */
  	br = 0x15;
! 	cvec = (uba_hd[numuba].uh_lastiv -= 4);
  	ex_cvecs[ex_ncall].xc_csraddr = addr;
  	ex_cvecs[ex_ncall].xc_cvec = cvec;
  	/*
--- 145,151 ----
  	 * We program the EXOS interrupt vector, like dmf device.
  	 */
  	br = 0x15;
! 	cvec = 0770;
  	ex_cvecs[ex_ncall].xc_csraddr = addr;
  	ex_cvecs[ex_ncall].xc_cvec = cvec;
  	/*
***************
*** 162,168 ****
  	excdint(0);
  #endif
  	ex_ncall++;
! 	return (sizeof(struct exdevice));
  }
  
  /*
--- 165,171 ----
  	excdint(0);
  #endif
  	ex_ncall++;
! 	return (1);
  }
  
  /*
***************
*** 179,184 ****
--- 182,190 ----
  	register struct exdevice *addr = (struct exdevice *)ui->ui_addr;
  	register struct ex_msg *bp;
  	int unit = ui->ui_unit;
+ 
+ 	if (ex_ncall == 0)
+ 		exinfo[unit] = ui;
  	ifp->if_unit = ui->ui_unit;
  	ifp->if_name = "ex";
  	ifp->if_mtu = ETHERMTU;
***************
*** 318,323 ****
--- 324,331 ----
  	int i;
  	u_long shiftreg;
  
+ 	if (ex_ncall == 0)
+ 		exprobe(addr);
  	xs->xs_flags = 0;
  	/*
  	 * Reset EXOS, wait for self-test to complete
***************
*** 331,340 ****
  	cm->cm_1rsrv = 1;
  	cm->cm_cc = 0xFF;
  	cm->cm_opmode = 0;		/* link-level controller mode */
! 	cm->cm_dfo = 0x0101;		/* enable host data order conversion */
  	cm->cm_dcn1 = 1;
! 	cm->cm_2rsrv[0] =
! 		cm->cm_2rsrv[1] = 0;
  	cm->cm_ham = 3;			/* absolute address mode */
  	cm->cm_3rsrv = 0;
  	cm->cm_mapsiz = 0;
--- 339,348 ----
  	cm->cm_1rsrv = 1;
  	cm->cm_cc = 0xFF;
  	cm->cm_opmode = 0;		/* link-level controller mode */
! 	cm->cm_dfo = 0x0101L;		/* enable host data order conversion */
  	cm->cm_dcn1 = 1;
! 	cm->cm_2rsrv[0] = 0;
! 	cm->cm_2rsrv[1] = 0;
  	cm->cm_ham = 3;			/* absolute address mode */
  	cm->cm_3rsrv = 0;
  	cm->cm_mapsiz = 0;
***************
*** 342,352 ****
  	cm->cm_byteptrn[1] = 0x03;	/*  by looking at this pattern */
  	cm->cm_byteptrn[2] = 0x07;
  	cm->cm_byteptrn[3] = 0x0F;
! 	cm->cm_wordptrn[0] = 0x0103;
! 	cm->cm_wordptrn[1] = 0x070F;
! 	cm->cm_lwordptrn = 0x0103070F;
  	for (i=0; i<20; i++) cm->cm_rsrvd[i] = 0;
! 	cm->cm_mba = 0xFFFFFFFF;
  	cm->cm_nproc = 0xFF;
  	cm->cm_nmbox = 0xFF;
  	cm->cm_nmcast = 0xFF;
--- 350,360 ----
  	cm->cm_byteptrn[1] = 0x03;	/*  by looking at this pattern */
  	cm->cm_byteptrn[2] = 0x07;
  	cm->cm_byteptrn[3] = 0x0F;
! 	cm->cm_wordptrn[0] = 0x0103L;
! 	cm->cm_wordptrn[1] = 0x070FL;
! 	cm->cm_lwordptrn = 0x0103070FL;
  	for (i=0; i<20; i++) cm->cm_rsrvd[i] = 0;
! 	cm->cm_mba = 0xFFFFFFFFL;
  	cm->cm_nproc = 0xFF;
  	cm->cm_nmbox = 0xFF;
  	cm->cm_nmcast = 0xFF;
***************
*** 402,408 ****
  	 * configuration to complete (guaranteed response
  	 * within 2 seconds).
  	 */
! 	shiftreg = (u_long)0x0000FFFF;
  	for (i = 0; i < 8; i++) {
  		if (i == 4)
  			shiftreg = P_UNIADDR(xs->xs_ubaddr) + CM_OFFSET(unit);
--- 410,416 ----
  	 * configuration to complete (guaranteed response
  	 * within 2 seconds).
  	 */
! 	shiftreg = (u_long)0x0000FFFFL;
  	for (i = 0; i < 8; i++) {
  		if (i == 4)
  			shiftreg = P_UNIADDR(xs->xs_ubaddr) + CM_OFFSET(unit);
***************
*** 411,417 ****
--- 419,428 ----
  		addr->xd_portb = (u_char)(shiftreg & 0xFF);
  		shiftreg >>= 8;
  	}
+ 	{
+ 	long i;
  	for (i = 1000000; (cm->cm_cc == 0xFF) && i; --i);
+ 	}
  	if (cm->cm_cc)
  		printf("ex%d: configuration failed; cc = %x\n",
  			unit, cm->cm_cc);
***************
*** 555,561 ****
--- 566,575 ----
      	struct mbuf *m;
  	register int len, off, resid;
  	register struct ifqueue *inq;
+ 	int s;
+ 	mapinfo map;
  
+ 	savemap(map);
  	xs->xs_if.if_ipackets++;
  	len = bp->mb_er.er_blks[0].bb_len - sizeof(struct ether_header) - 4;
  	if (bp->mb_rply != LL_OK) {
***************
*** 562,570 ****
  		xs->xs_if.if_ierrors++;
  		printf("ex%d: receive error=%b\n",
  			unit, bp->mb_rply, RECV_BITS);
  		return;
  	}
! 	eh = (struct ether_header *)(xs->xs_ifuba.ifu_r.ifrw_addr);
  
  	/*
  	 * Deal with trailer protocol: if type is trailer
--- 576,586 ----
  		xs->xs_if.if_ierrors++;
  		printf("ex%d: receive error=%b\n",
  			unit, bp->mb_rply, RECV_BITS);
+ 		restormap(map);
  		return;
  	}
! 	mapseg5(xs->xs_ifuba.ifu_r.ifrw_click, MBMAPSIZE);
! 	eh = (struct ether_header *)MBX;
  
  	/*
  	 * Deal with trailer protocol: if type is trailer
***************
*** 576,592 ****
  	if (eh->ether_type >= ETHERTYPE_TRAIL &&
  	    eh->ether_type < ETHERTYPE_TRAIL+ETHERTYPE_NTRAILER) {
  		off = (eh->ether_type - ETHERTYPE_TRAIL) * 512;
! 		if (off >= ETHERMTU)
  			return;		/* sanity */
  		eh->ether_type = ntohs(*exdataaddr(eh, off, u_short *));
  		resid = ntohs(*(exdataaddr(eh, off+2, u_short *)));
! 		if (off + resid > len)
  			return;		/* sanity */
  		len = off + resid;
  	} else
  		off = 0;
! 	if (len == 0)
  		return;
  
  	/*
  	 * Pull packet off interface.  Off is nonzero if packet
--- 592,614 ----
  	if (eh->ether_type >= ETHERTYPE_TRAIL &&
  	    eh->ether_type < ETHERTYPE_TRAIL+ETHERTYPE_NTRAILER) {
  		off = (eh->ether_type - ETHERTYPE_TRAIL) * 512;
! 		if (off >= ETHERMTU) {
! 			restormap(map);
  			return;		/* sanity */
+ 		}
  		eh->ether_type = ntohs(*exdataaddr(eh, off, u_short *));
  		resid = ntohs(*(exdataaddr(eh, off+2, u_short *)));
! 		if (off + resid > len) {
! 			restormap(map);
  			return;		/* sanity */
+ 		}
  		len = off + resid;
  	} else
  		off = 0;
! 	if (len == 0) {
! 		restormap(map);
  		return;
+ 	}
  
  	/*
  	 * Pull packet off interface.  Off is nonzero if packet
***************
*** 595,602 ****
  	 * the type and length which are at the front of any trailer data.
  	 */
  	m = if_rubaget(&xs->xs_ifuba, len, off, &xs->xs_if);
! 	if (m == 0)
  		return;
  	if (off) {
  		struct ifnet *ifp;
  
--- 617,626 ----
  	 * the type and length which are at the front of any trailer data.
  	 */
  	m = if_rubaget(&xs->xs_ifuba, len, off, &xs->xs_if);
! 	if (m == 0) {
! 		restormap(map);
  		return;
+ 	}
  	if (off) {
  		struct ifnet *ifp;
  
***************
*** 615,620 ****
--- 639,645 ----
  
  	case ETHERTYPE_ARP:
  		arpinput(&xs->xs_ac, m);
+ 		restormap(map);
  		return;
  #endif
  #ifdef NS
***************
*** 626,640 ****
  #endif
  	default:
  		m_freem(m);
  		return;
  	}
  
  	if (IF_QFULL(inq)) {
  		IF_DROP(inq);
  		m_freem(m);
! 		return;
! 	}
! 	IF_ENQUEUE(inq, m);
  }
  
  /*
--- 651,668 ----
  #endif
  	default:
  		m_freem(m);
+ 		restormap(map);
  		return;
  	}
  
+ 	s = splimp();
  	if (IF_QFULL(inq)) {
  		IF_DROP(inq);
  		m_freem(m);
! 	} else
! 		IF_ENQUEUE(inq, m);
! 	splx(s);
! 	restormap(map);
  }
  
  /*
***************
*** 677,683 ****
--- 705,713 ----
  	register struct ether_header *eh;
  	register int off;
  	int usetrailers;
+ 	segm save5;
  
+ 	saveseg5(save5);
  	if ((ifp->if_flags & (IFF_UP|IFF_RUNNING)) != (IFF_UP|IFF_RUNNING)) {
  		error = ENETDOWN;
  		goto bad;
***************
*** 687,694 ****
  #ifdef INET
  	case AF_INET:
  		idst = ((struct sockaddr_in *)dst)->sin_addr;
! 		if (!arpresolve(&xs->xs_ac, m, &idst, edst, &usetrailers))
  			return (0);	/* if not yet resolved */
  		off = ntohs((u_short)mtod(m, struct ip *)->ip_len) - m->m_len;
  		if (usetrailers && off > 0 && (off & 0x1ff) == 0 &&
  		    m->m_off >= MMINOFF + 2 * sizeof (u_short)) {
--- 717,726 ----
  #ifdef INET
  	case AF_INET:
  		idst = ((struct sockaddr_in *)dst)->sin_addr;
! 		if (!arpresolve(&xs->xs_ac, m, &idst, edst, &usetrailers)) {
! 			restorseg5(save5);
  			return (0);	/* if not yet resolved */
+ 		}
  		off = ntohs((u_short)mtod(m, struct ip *)->ip_len) - m->m_len;
  		if (usetrailers && off > 0 && (off & 0x1ff) == 0 &&
  		    m->m_off >= MMINOFF + 2 * sizeof (u_short)) {
***************
*** 786,795 ****
--- 818,829 ----
  	}
  #endif
  	splx(s);
+ 	restorseg5(save5);
  	return (0);
  
  bad:
  	m_freem(m0);
+ 	restorseg5(save5);
  	return (error);
  }
  
***************
*** 897,903 ****
  	
  	if (physaddr) {
  		xs->xs_flags |= EX_SETADDR;
! 		bcopy((caddr_t)physaddr, (caddr_t)xs->xs_addr, 6);
  	}
  	if (! (xs->xs_flags & EX_RUNNING))
  		return;
--- 931,937 ----
  	
  	if (physaddr) {
  		xs->xs_flags |= EX_SETADDR;
! 		bcopy(physaddr, xs->xs_addr, 6);
  	}
  	if (! (xs->xs_flags & EX_RUNNING))
  		return;
***************
*** 905,911 ****
  	bp->mb_rqst = LLNET_ADDRS;
  	bp->mb_na.na_mask = READ_OBJ|WRITE_OBJ;
  	bp->mb_na.na_slot = PHYSSLOT;
! 	bcopy((caddr_t)xs->xs_addr, (caddr_t)bp->mb_na.na_addrs, 6);
  	bp->mb_status |= MH_EXOS;
  	addr->xd_portb = EX_NTRUPT;
  	bp = xs->xs_x2hnext;
--- 939,945 ----
  	bp->mb_rqst = LLNET_ADDRS;
  	bp->mb_na.na_mask = READ_OBJ|WRITE_OBJ;
  	bp->mb_na.na_slot = PHYSSLOT;
! 	bcopy(xs->xs_addr, bp->mb_na.na_addrs, 6);
  	bp->mb_status |= MH_EXOS;
  	addr->xd_portb = EX_NTRUPT;
  	bp = xs->xs_x2hnext;
***************
*** 928,931 ****
  	while ((bp->mb_status & MH_OWNER) == MH_EXOS)	/* poll for reply */
  		;
  }
! #endif
--- 962,965 ----
  	while ((bp->mb_status & MH_OWNER) == MH_EXOS)	/* poll for reply */
  		;
  }
! #endif NEX

*** if_exreg.h	Fri Oct 14 17:06:19 1988
--- /sys/vaxif/if_exreg.h	Tue Sep 27 17:16:55 1988
***************
*** 6,11 ****
--- 6,18 ----
   *	@(#)if_exreg.h	7.1 (Berkeley) 6/5/86
   */
  
+ /*
+  * Modification from Berkeley 4.3BSD
+  *
+  *	Kenichi Katsumi
+  *	SONY/TEKTRONIX Corp.
+  *				88/09/20
+  */
  
  struct	exdevice {
  	char	xd_porta;	/* write on porta resets EXOS */
***************
*** 193,200 ****
--- 200,212 ----
  		struct	net_addrs	mb_net_addrs;
  		struct	net_recv	mb_net_recv;
  		struct	net_ststcs	mb_net_ststcs;
+ #ifndef pdp11
  		struct	enet_xmit	mb_enet_xmit;
  		struct	enet_recv	mb_enet_recv;
+ #else
+ 		struct	enet_xmit	mbenet_xmit;
+ 		struct	enet_recv	mbenet_recv;
+ #endif
  	} mb_all;
  /* following field is used only by host, not read by board */
  	struct	ex_msg *mb_next;	/* host's pointer to next message */
***************
*** 203,210 ****
--- 215,227 ----
  #define	mb_na	mb_all.mb_net_addrs
  #define	mb_nr	mb_all.mb_net_recv
  #define	mb_ns	mb_all.mb_net_ststcs
+ #ifndef pdp11
  #define	mb_et	mb_all.mb_enet_xmit
  #define	mb_er	mb_all.mb_enet_recv
+ #else
+ #define	mb_et	mb_all.mbenet_xmit
+ #define	mb_er	mb_all.mbenet_recv
+ #endif
  #define	mb_rqst	mb_nm.nm_rqst
  #define	mb_rply	mb_nm.nm_rply
  #define	MBDATALEN (sizeof(union mb_all)+6)

*** scb.s	Fri Oct 14 17:12:59 1988
--- /sys/machine/scb.s	Tue Sep 13 00:09:16 1988
***************
*** 11,16 ****
--- 11,17 ----
  #include "../machine/mch_iopage.h"
  #include "../machine/koverlay.h"	/* for OVLY_TABLE_BASE */
  
+ #include "ex.h"
  #include "de.h"
  #include "dh.h"
  #include "dhu.h"
***************
*** 192,197 ****
--- 193,202 ----
  #endif
  
  
+ #if NEX > 0				/* EXOS 204 */
+ 	DEVTRAP(770,	excdint, br5+0.)
+ #endif
+ 
  /*
   * End of floating vectors.  Endvec should be past vector space if NONSEP,
   * should be at least 450.
***************
*** 388,391 ****
--- 393,400 ----
  
  #if NDZ > 0				/* DZ */
  	HANDLER(dzrint)
+ #endif
+ 
+ #if NEX > 0
+ 	HANDLER(excdint)		/* EXOS204 */
  #endif

*** dtab	Fri Oct 14 17:15:24 1988
--- /etc/dtab	Wed Sep 28 16:18:28 1988
***************
*** 36,38 ****
--- 36,39 ----
  # kw	? 172540 100	6	hardclock	# kw11-p clock
  # sr	?        500	5	srirint	srixint	# sri dr11-c arpanet imp
  # vv	? 161000 350	5	vvrint	vvxint	# pronet
+ # ex	? 164100 770	5	excdint		# excelan exos204