From 8c0439feaa976c6a4cec11b024dddd694c71edb9 Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Sun, 24 Jun 2018 03:21:22 -0700
Subject: [PATCH] PDP11, VAX: Fix RQ and TQ Get Unit Status to properly report
 no more units

As reported in #592
---
 PDP11/pdp11_rq.c |  6 +++++-
 PDP11/pdp11_tq.c | 10 +++++++---
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/PDP11/pdp11_rq.c b/PDP11/pdp11_rq.c
index 4ffc22f3..c8bb0c6c 100644
--- a/PDP11/pdp11_rq.c
+++ b/PDP11/pdp11_rq.c
@@ -813,6 +813,7 @@ typedef struct {
     struct uq_ring      cq;                             /* cmd ring */
     struct uq_ring      rq;                             /* rsp ring */
     struct rqpkt        pak[RQ_NPKTS];                  /* packet queue */
+    uint16              max_plug;                       /* highest unit plug number */
     } MSC;
 
 /* debugging bitmaps */
@@ -1798,7 +1799,7 @@ UNIT *uptr;
 sim_debug (DBG_TRC, rq_devmap[cp->cnum], "rq_gus\n");
 
 if (cp->pak[pkt].d[CMD_MOD] & MD_NXU) {                 /* next unit? */
-    if (lu == 65535) {                                  /* end of range? */
+    if (lu > cp->max_plug) {                            /* beyond last unit plug? */
         lu = 0;                                         /* reset to 0 */
         cp->pak[pkt].d[RSP_UN] = lu;
         }
@@ -3006,6 +3007,9 @@ for (i = 0; i < (RQ_NUMDR + 2); i++) {                  /* init units */
     if (uptr->rqxb == NULL)
         return SCPE_MEM;
     }
+for (i=cp->max_plug=0; i<RQ_NUMDR; i++)
+    if (dptr->units[i].unit_plug > cp->max_plug)
+        cp->max_plug = (uint16)dptr->units[i].unit_plug;
 return auto_config (0, 0);                              /* run autoconfig */
 }
 
diff --git a/PDP11/pdp11_tq.c b/PDP11/pdp11_tq.c
index 9a17f9c2..3bfbddb0 100644
--- a/PDP11/pdp11_tq.c
+++ b/PDP11/pdp11_tq.c
@@ -256,8 +256,9 @@ uint32 tq_pip = 0;                                      /* poll in progress */
 struct uq_ring tq_cq = { 0 };                           /* cmd ring */
 struct uq_ring tq_rq = { 0 };                           /* rsp ring */
 struct tqpkt tq_pkt[TQ_NPKTS];                          /* packet queue */
-uint16 tq_freq = 0;                                      /* free list */
-uint16 tq_rspq = 0;                                      /* resp list */
+uint16 tq_freq = 0;                                     /* free list */
+uint16 tq_rspq = 0;                                     /* resp list */
+uint16 tq_max_plug;                                     /* highest unit plug number */
 uint32 tq_pbsy = 0;                                     /* #busy pkts */
 uint32 tq_credits = 0;                                  /* credits */
 uint32 tq_hat = 0;                                      /* host timer */
@@ -1019,7 +1020,7 @@ UNIT *uptr;
 sim_debug(DBG_TRC, &tq_dev, "tq_gus\n");
 
 if (tq_pkt[pkt].d[CMD_MOD] & MD_NXU) {                  /* next unit? */
-    if (lu == 65535) {                                  /* end of range? */
+    if (lu > tq_max_plug) {                             /* beyond last unit plug? */
         lu = 0;                                         /* reset to 0 */
         tq_pkt[pkt].d[RSP_UN] = (uint16)lu;
         }
@@ -2068,6 +2069,9 @@ int32 i, j;
 UNIT *uptr;
 static t_bool plugs_inited = FALSE;
 
+for (i=tq_max_plug=0; i<TQ_NUMDR; i++)
+    if (dptr->units[i].unit_plug > tq_max_plug)
+        tq_max_plug = (uint16)dptr->units[i].unit_plug;
 if (!plugs_inited ) {
     uint32 d;
     char uname[16];