SCP: Properly write debug output for commands run at the sim> prompt

- Without regard to whether the circular buffer data is otherwise in
   use while instructions are executing.
- When a circular debug buffer is in use, avoid writing out the contents
  with the periodic open file flushes and only do so on returns to the
  sim> prompt and when debug is closed

scp.c

@@ -3192,8 +3192,9 @@ if ((stat = sim_brk_init ()) != SCPE_OK) {
     sim_exit_status = EXIT_FAILURE;
     goto cleanup_and_exit;
     }
-/* always check for register definition problems */
-sim_sanity_check_register_declarations (NULL);
+/* always check for register definition problems, unless we already did that */
+if (register_check == FALSE)
+    sim_sanity_check_register_declarations (NULL);
 
 if (device_unit_tests) {
     int i;
@@ -9604,7 +9605,7 @@ if (warned)
 return r;
 }
 
-void sim_flush_buffered_files (void)
+void sim_flush_buffered_files (t_bool debug_flush)
 {
 uint32 i, j;
 DEVICE *dptr;
@@ -9612,7 +9613,7 @@ UNIT *uptr;
 
 if (sim_log)                                            /* flush console log */
     fflush (sim_log);
-if (sim_deb)                                            /* flush debug log */
+if (debug_flush && (sim_deb != NULL))                   /* flush debug log */
     _sim_debug_flush ();
 for (i = 1; (dptr = sim_devices[i]) != NULL; i++) {     /* flush attached files */
     for (j = 0; j < dptr->numunits; j++) {              /* if not buffered in mem */
@@ -9640,7 +9641,7 @@ t_stat
 flush_svc (UNIT *uptr)
 {
 sim_activate_after (uptr, sim_flush_interval * 1000000);
-sim_flush_buffered_files ();
+sim_flush_buffered_files (FALSE);
 return SCPE_OK;
 }
 
@@ -9920,7 +9921,7 @@ sim_brk_clrall (BRK_TYP_DYN_STEPOVER);                  /* cancel any step/over
 signal (SIGHUP, sigterm_received ? SIG_IGN : SIG_DFL);  /* cancel WRU */
 #endif
 signal (SIGTERM, sigterm_received ? SIG_IGN : SIG_DFL); /* cancel WRU */
-sim_flush_buffered_files();
+sim_flush_buffered_files (TRUE);
 sim_cancel (&sim_flush_unit);                           /* cancel flush timer */
 sim_cancel_step ();                                     /* cancel step timer */
 sim_throt_cancel ();                                    /* cancel throttle */
@@ -14232,9 +14233,9 @@ return SCPE_OK;
 void _sim_scp_abort (const char *msg, const char *file, int linenum)
 {
 sim_printf ("%s - aborting from %s:%d\n", msg, file, linenum);
-sim_flush_buffered_files ();
+sim_flush_buffered_files (TRUE);
 if (sim_deb)
-    fclose (sim_deb);
+    sim_set_deboff (0, NULL);
 abort ();
 }
 
@@ -14269,7 +14270,7 @@ static void _debug_fwrite (const char *buf, size_t len)
 {
 size_t move_size;
 
-if (sim_deb_buffer == NULL) {
+if ((sim_deb_buffer == NULL) || (!sim_is_running)) {
     _debug_fwrite_all (buf, len, sim_deb);  /* output now. */
     return;
     }

scp.h

@@ -277,7 +277,7 @@ void _sim_debug_device (uint32 dbits, DEVICE* dptr, const char* fmt, ...) GCC_FM
 #define sim_debug(dbits, dptr, ...) do { if ((sim_deb != NULL) && ((dptr) != NULL) && ((dptr)->dctrl & (dbits))) _sim_debug_device (dbits, dptr, __VA_ARGS__);} while (0)
 #define sim_debug_unit(dbits, uptr, ...) do { if ((sim_deb != NULL) && ((uptr) != NULL) && (uptr->dptr != NULL) && (((uptr)->dctrl | (uptr)->dptr->dctrl) & (dbits))) _sim_debug_unit (dbits, uptr, __VA_ARGS__);} while (0)
 #endif
-void sim_flush_buffered_files (void);
+void sim_flush_buffered_files (t_bool debug_flush);
 
 /* Only for use in SCP code and libraries - NOT in simulator code */
 #define SIM_SCP_ABORT(msg) _sim_scp_abort (msg, __FILE__, __LINE__)

sim_console.c

@@ -1437,7 +1437,7 @@ for (i=(was_active_command ? sim_rem_cmd_active_line : 0);
             sim_is_running = FALSE;
             sim_rem_collect_all_registers ();
             sim_stop_timer_services ();
-            sim_flush_buffered_files ();
+            sim_flush_buffered_files (TRUE);
             if (rem->act == NULL) {
                 for (j=0; j < sim_rem_con_tmxr.lines; j++) {
                     TMLN *lpj = &sim_rem_con_tmxr.ldsc[j];
@@ -1468,7 +1468,7 @@ for (i=(was_active_command ? sim_rem_cmd_active_line : 0);
                     sim_is_running = FALSE;
                     sim_rem_collect_all_registers ();
                     sim_stop_timer_services ();
-                    sim_flush_buffered_files ();
+                    sim_flush_buffered_files (TRUE);
                     stat = SCPE_STOP;
                     _sim_rem_message ("RUN", stat);
                     _sim_rem_log_out (lp);
@@ -2414,13 +2414,18 @@ t_stat sim_set_deboff (int32 flag, CONST char *cptr)
 {
 if (cptr && (*cptr != 0))                               /* now eol? */
     return SCPE_2MARG;
-if (sim_deb == NULL)                                    /* no debug? */
-    return SCPE_OK;
+if (sim_deb == NULL) {                                  /* no debug? */
+    if  (cptr != NULL)
+        return sim_messagef (SCPE_OK, "Debug not enabled\n");
+    else
+        return SCPE_OK;
+    }
 if (sim_deb_switches & SWMASK ('B')) {
     size_t offset = (sim_debug_buffer_inuse == sim_deb_buffer_size) ? sim_debug_buffer_offset : 0;
-    const char *bufmsg = "Circular Buffer Contents follow here:\n\n";
+    const char *bufmsg = "\nCircular Buffer Contents follow here:\n\n";
 
-    fwrite (bufmsg, 1, strlen (bufmsg), sim_deb);
+    if (sim_debug_buffer_inuse > 0)
+        fwrite (bufmsg, 1, strlen (bufmsg), sim_deb);
 
     while (sim_debug_buffer_inuse > 0) {
         size_t write_size = MIN (sim_deb_buffer_size - offset, sim_debug_buffer_inuse);

sim_tape.c

@@ -982,7 +982,7 @@ if (r == SCPE_OK) {
     }
 
 if ((sim_switches & SWMASK ('D')) && !had_debug)
-    sim_set_deboff (0, "");
+    sim_set_deboff (0, NULL);
 if (sim_switches & SWMASK ('D'))
     uptr->dctrl = starting_dctrl;
 if ((r == SCPE_OK) && (sim_switches & SWMASK ('X')))