From e519c93ebf8855a83e8ee95641c8e9a6386f35c7 Mon Sep 17 00:00:00 2001
From: Mark Pizzolato <mark@infocomm.com>
Date: Tue, 8 Jun 2021 14:25:23 -0700
Subject: [PATCH] H316, NOVA, PDP11, PDP8, PDP18B, KX10: Record Sequential
 updates consistently

Devices that do single character I/O could be attached to non seekable
host OS devices (tty, pipes, etc.) and thus shouldn't count on fseek()
and ftell().  These DEVICEs on these simulators do single character I/O
and easily can update their POS REGisters to reflect how much data has
been emitted.  Changing such a REGister will have no  useful effect
when attached to a non seekable file.
---
 H316/h316_stddev.c | 8 ++++----
 NOVA/nova_lp.c     | 2 +-
 PDP10/kx10_pt.c    | 2 +-
 PDP11/pdp11_lp.c   | 2 +-
 PDP18B/pdp18b_lp.c | 2 +-
 PDP8/pdp8_lp.c     | 2 +-
 6 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/H316/h316_stddev.c b/H316/h316_stddev.c
index cf519a9f..5752f634 100644
--- a/H316/h316_stddev.c
+++ b/H316/h316_stddev.c
@@ -408,7 +408,7 @@ else {
         }
     else if ((uptr->flags & UNIT_ASC) && (c != 0))      /* ASCII? */
         c = c | 0200;
-    uptr->pos = ftell (uptr->fileref);                  /* update pos */
+    uptr->pos = uptr->pos + 1;                          /* update pos */
     }
 SET_INT (INT_PTR);                                      /* set ready flag */
 uptr->buf = c & 0377;                                   /* get byte */
@@ -568,7 +568,7 @@ if (putc (c, uptr->fileref) == EOF) {                   /* output byte */
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
-uptr->pos = ftell (uptr->fileref);                      /* update pos */
+uptr->pos = uptr->pos + 1;                              /* update pos */
 return SCPE_OK;
 }
 
@@ -704,7 +704,7 @@ else if ((ruptr->flags & UNIT_ATT) &&                   /* TTR attached */
             }
         else if ((ruptr->flags & UNIT_ASC) && (c != 0))
             c = c | 0200;                               /* ASCII nz? cvt */
-        ruptr->pos = ftell (ruptr->fileref);
+        ruptr->pos = ruptr->pos + 1;
         }
     if (ttr_xoff_read != 0) {                           /* reader stopping? */
         if (c == RUBOUT)                                /* rubout? stop */
@@ -808,7 +808,7 @@ if ((puptr->flags & UNIT_ATT) &&                        /* TTP attached */
             clearerr (puptr->fileref);
             return SCPE_IOERR;
             }
-        puptr->pos = ftell (puptr->fileref);            /* update pos */
+        puptr->pos = puptr->pos + 1;                    /* update pos */
         }
     }
 return SCPE_OK;
diff --git a/NOVA/nova_lp.c b/NOVA/nova_lp.c
index c7f71d56..59de2380 100644
--- a/NOVA/nova_lp.c
+++ b/NOVA/nova_lp.c
@@ -133,12 +133,12 @@ DEV_UPDATE_INTR ;
 if ((lpt_unit.flags & UNIT_ATT) == 0)                   /* attached? */
     return IORETURN (lpt_stopioe, SCPE_UNATT);
 fputc (uptr->buf, uptr->fileref);
-uptr->pos = ftell (uptr->fileref);
 if (ferror (uptr->fileref)) {
     sim_perror ("LPT I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
+uptr->pos = uptr->pos + 1;
 return SCPE_OK;
 }
 
diff --git a/PDP10/kx10_pt.c b/PDP10/kx10_pt.c
index 6a326e3c..842463af 100644
--- a/PDP10/kx10_pt.c
+++ b/PDP10/kx10_pt.c
@@ -181,12 +181,12 @@ t_stat ptp_svc (UNIT *uptr)
         return SCPE_OK;
     }
     fputc (uptr->CHR, uptr->fileref);                       /* print char */
-    uptr->pos = ftell (uptr->fileref);
     if (ferror (uptr->fileref)) {                           /* error? */
         perror ("PTP I/O error");
         clearerr (uptr->fileref);
         return SCPE_IOERR;
     }
+    uptr->pos = uptr->pos + 1;
     return SCPE_OK;
 }
 
diff --git a/PDP11/pdp11_lp.c b/PDP11/pdp11_lp.c
index e9fb881b..0410e9ae 100644
--- a/PDP11/pdp11_lp.c
+++ b/PDP11/pdp11_lp.c
@@ -163,12 +163,12 @@ if (lpt_csr & CSR_IE)
 if ((uptr->flags & UNIT_ATT) == 0)
     return IORETURN (lpt_stopioe, SCPE_UNATT);
 fputc (uptr->buf & 0177, uptr->fileref);
-uptr->pos = ftell (uptr->fileref);
 if (ferror (uptr->fileref)) {
     sim_perror ("LPT I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
+uptr->pos = uptr->pos + 1;
 lpt_csr = lpt_csr & ~CSR_ERR;
 return SCPE_OK;
 }
diff --git a/PDP18B/pdp18b_lp.c b/PDP18B/pdp18b_lp.c
index 0db2ec41..b7ab1d1e 100644
--- a/PDP18B/pdp18b_lp.c
+++ b/PDP18B/pdp18b_lp.c
@@ -623,12 +623,12 @@ c = uptr->buf & 0177;                                   /* get char */
 if ((c == 0) || (c == 0177))                            /* skip NULL, DEL */
     return SCPE_OK;
 fputc (c, uptr->fileref);                               /* print char */
-uptr->pos = ftell (uptr->fileref);                      /* update position */
 if (ferror (uptr->fileref)) {                           /* error? */
     sim_perror ("LPT I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
+uptr->pos = uptr->pos + 1;                              /* update position */
 return SCPE_OK;
 }
 
diff --git a/PDP8/pdp8_lp.c b/PDP8/pdp8_lp.c
index 092758b6..d352e825 100644
--- a/PDP8/pdp8_lp.c
+++ b/PDP8/pdp8_lp.c
@@ -149,12 +149,12 @@ if ((uptr->flags & UNIT_ATT) == 0) {
     return IORETURN (lpt_stopioe, SCPE_UNATT);
     }
 fputc (uptr->buf, uptr->fileref);                       /* print char */
-uptr->pos = ftell (uptr->fileref);
 if (ferror (uptr->fileref)) {                           /* error? */
     sim_perror ("LPT I/O error");
     clearerr (uptr->fileref);
     return SCPE_IOERR;
     }
+uptr->pos = uptr->pos + 1;
 return SCPE_OK;
 }