Migrating scp and library global variables to be declared as extern in the appropriate library include file and remove repetitive declarations in referencing modules.

PDP1/pdp1_cpu.c

@@ -335,10 +335,6 @@ int32 hst_p = 0;                                        /* history pointer */
 int32 hst_lnt = 0;                                      /* history length */
 InstHistory *hst = NULL;                                /* inst history */
 
-extern UNIT *sim_clock_queue;
-extern int32 sim_int_char;
-extern uint32 sim_brk_types, sim_brk_dflt, sim_brk_summ; /* breakpoint info */
-
 t_stat cpu_ex (t_value *vptr, t_addr addr, UNIT *uptr, int32 sw);
 t_stat cpu_dep (t_value val, t_addr addr, UNIT *uptr, int32 sw);
 t_stat cpu_reset (DEVICE *dptr);
@@ -503,7 +499,6 @@ DEVICE cpu_dev = {
 
 t_stat sim_instr (void)
 {
-extern int32 sim_interval;
 int32 IR, op, i, t, xct_count;
 int32 sign, signd, v, sbs_lvl, byno;
 int32 dev, pulse, io_data, sc, skip;
@@ -1656,8 +1651,6 @@ char *cptr = (char *) desc;
 t_stat r;
 t_value sim_eval;
 InstHistory *h;
-extern t_stat fprint_sym (FILE *ofile, t_addr addr, t_value *val,
-    UNIT *uptr, int32 sw);
 
 if (hst_lnt == 0)                                       /* enabled? */
     return SCPE_NOFNC;

PDP1/pdp1_dt.c

@@ -250,9 +250,6 @@
 extern int32 M[];
 extern int32 stop_inst;
 extern UNIT cpu_unit;
-extern int32 sim_switches;
-extern int32 sim_is_running;
-extern FILE *sim_deb;
 
 int32 dtsa = 0;                                         /* status A */
 int32 dtsb = 0;                                         /* status B */

PDP1/pdp1_sys.c

@@ -65,7 +65,6 @@ extern int32 M[];
 extern int32 PC;
 extern int32 ascii_to_fiodec[], fiodec_to_ascii[];
 extern int32 sc_map[];
-extern int32 sim_switches;
 
 /* SCP data structures and interface routines