From af0754f93ae3f98441f44e65e7b3a43b324fb0a6 Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Fri, 16 Apr 2021 11:33:42 -0700
Subject: [PATCH] PDP11: Clarify TC device attach and detach read only & write
 update messages

As discussed in #1034
---
 PDP11/pdp11_tc.c | 40 ++++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/PDP11/pdp11_tc.c b/PDP11/pdp11_tc.c
index 8012651a..617dfdad 100644
--- a/PDP11/pdp11_tc.c
+++ b/PDP11/pdp11_tc.c
@@ -127,7 +127,7 @@
 #define STATE           u3                              /* unit state */
 #define LASTT           u4                              /* last time update */
 #define WRITTEN         u5                              /* device buffer is dirty and needs flushing */
-#define UNIT_WPRT       (UNIT_WLK | UNIT_RO)            /* write protect */
+#define UNIT_WPRT       (UNIT_WLK)                      /* write protect */
 
 /* System independent DECtape constants */
 
@@ -313,6 +313,8 @@ void dt_stopunit (UNIT *uptr);
 int32 dt_comobv (int32 val);
 int32 dt_csum (UNIT *uptr, int32 blk);
 int32 dt_gethdr (UNIT *uptr, int32 blk, int32 relpos);
+t_stat dt_set_writelock (UNIT *uptr, int32 val, CONST char *cptr, void *desc);
+t_stat dt_show_writelock (FILE *st, UNIT *uptr, int32 val, CONST void *desc);
 t_stat dt_help (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr);
 const char *dt_description (DEVICE *dptr);
 
@@ -381,10 +383,10 @@ REG dt_reg[] = {
     };
 
 MTAB dt_mod[] = {
-    { UNIT_WLK,        0, "write enabled", "WRITEENABLED", 
-        NULL, NULL, NULL, "Write enable tape drive" },
-    { UNIT_WLK, UNIT_WLK, "write locked",  "LOCKED", 
-        NULL, NULL, NULL, "Write lock tape drive"  },
+    { MTAB_XTD|MTAB_VUN, 0, "write enabled", "WRITEENABLED", 
+        &dt_set_writelock, &dt_show_writelock,   NULL, "Write enable tape drive" },
+    { MTAB_XTD|MTAB_VUN, 1, NULL, "LOCKED", 
+        &dt_set_writelock, NULL,   NULL, "Write enable tape drive" },
     { UNIT_8FMT + UNIT_11FMT,          0, "18b", NULL },
     { UNIT_8FMT + UNIT_11FMT,  UNIT_8FMT, "12b", NULL },
     { UNIT_8FMT + UNIT_11FMT, UNIT_11FMT, "16b", NULL },
@@ -1269,6 +1271,8 @@ uint32 ba, sz, k, *fbuf;
 int32 u = uptr - dt_dev.units;
 t_stat r;
 
+if (uptr->flags & UNIT_WPRT)                            /* Write locked drive? */
+    sim_switches |= SWMASK ('R');                       /* Force Read Only Open */
 r = attach_unit (uptr, cptr);                           /* attach */
 if (r != SCPE_OK)                                       /* fail? */
     return r;
@@ -1354,6 +1358,7 @@ int32 k;
 uint32 ba, *fbuf;
 
 if (uptr->WRITTEN && uptr->hwmark && ((uptr->flags & UNIT_RO)== 0)) {    /* any data? */
+    sim_printf ("%s: writing buffer to file\n", sim_uname (uptr));
     rewind (uptr->fileref);                             /* start of file */
     fbuf = (uint32 *) uptr->filebuf;                    /* file buffer */
     if (uptr->flags & UNIT_8FMT) {                      /* 12b? */
@@ -1405,18 +1410,33 @@ if (sim_is_active (uptr)) {                             /* active? cancel op */
         }
     uptr->STATE = 0, uptr->pos = 0;
     }
-if (uptr->hwmark && ((uptr->flags & UNIT_RO) == 0)) {   /* any data? */
-    sim_printf ("%s%d: writing buffer to file\n", sim_dname (&dt_dev), u);
-    dt_flush (uptr);
-    }                                                   /* end if hwmark */
+if (uptr->hwmark && ((uptr->flags & UNIT_RO) == 0))     /* any data? */
+    dt_flush (uptr);                                    /* end if hwmark */
 free (uptr->filebuf);                                   /* release buf */
-uptr->flags = uptr->flags & ~UNIT_BUF;                  /* clear buf flag */
+uptr->flags = uptr->flags & ~(UNIT_BUF | UNIT_RO);      /* clear buf & read only flags */
 uptr->filebuf = NULL;                                   /* clear buf ptr */
 uptr->flags = (uptr->flags | UNIT_11FMT) & ~UNIT_8FMT;  /* default fmt */
 uptr->capac = DT_CAPAC;                                 /* default size */
 return detach_unit (uptr);
 }
 
+t_stat dt_set_writelock (UNIT *uptr, int32 val, CONST char *cptr, void *desc)
+{
+if ((uptr->flags & UNIT_ATT) != 0)
+    return sim_messagef (SCPE_ALATT, "%s: Already attached\n", sim_uname (uptr));
+if (val)
+    uptr->flags |= UNIT_WPRT;
+else
+    uptr->flags &= ~UNIT_WPRT;
+return SCPE_OK;
+}
+
+t_stat dt_show_writelock (FILE *st, UNIT *uptr, int32 val, CONST void *desc)
+{
+fprintf (st, "write %s", (uptr->flags & (UNIT_WPRT | UNIT_RO)) ? "locked" : "enabled");
+return SCPE_OK;
+}
+
 t_stat dt_help (FILE *st, DEVICE *dptr, UNIT *uptr, int32 flag, const char *cptr)
 {
 const char *text2;