SCP: Adjust RUNLIMIT time values on slow host systems

As reported and discussed in #819

PDP8/tests/pdp8_test.ini

@@ -8,6 +8,9 @@ cd %~p0
 
 :: Limit maximum diagnostic execution time
 runlimit 2 minutes
+set on
+on error ignore
+on runtime echof "\r\n*** Test Runtime Limit %SIM_RUNLIMIT% %SIM_RUNLIMIT_UNITS% Exceeded ***\n"; exit 1
 
 :: Maximum memory, extended address element:
 set cpu 32k

VAX/tests/vax-diag_test.ini

@@ -19,6 +19,10 @@
 #break A3B4 SHOW HIST=40
 cd %~p0
 set runlimit 2 minutes
+set on
+on error ignore
+on runtime echof "\r\n*** Test Runtime Limit %SIM_RUNLIMIT% %SIM_RUNLIMIT_UNITS% Exceeded ***\n"; exit 1
+
 set env DIAG_QUIET_MODE=0
 if ("%1" == "-v") set console notelnet
 else set -qu console telnet=localhost:65432,telnet=buffered; set env -a DIAG_QUIET_MODE=1

scp.c

@@ -7005,6 +7005,8 @@ char gbuf[CBUFSIZE];
 int32 num;
 t_stat r;
 double usec_factor = 1.0;
+const char *units = "";
+char runlimit[32];
 
 GET_SWITCHES (cptr);                                    /* get switches */
 if (0 == flag) {
@@ -7014,6 +7016,8 @@ if (0 == flag) {
     sim_runlimit_switches = 0;
     sim_runlimit_enabled = FALSE;
     sim_cancel (&sim_runlimit_unit);
+    unsetenv ("SIM_RUNLIMIT");
+    unsetenv ("SIM_RUNLIMIT_UNITS");
     return SCPE_OK;
     }
 
@@ -7023,8 +7027,10 @@ if ((r != SCPE_OK) || (num == 0))               /* error? */
     return sim_messagef (SCPE_ARG, "Invalid argument: %s\n", gbuf);
 cptr = get_glyph (cptr, gbuf, 0);               /* get next glyph */
 if ((gbuf[0] == '\0') ||
-    (MATCH_CMD (gbuf, sim_vm_interval_units) == 0))
+    (MATCH_CMD (gbuf, sim_vm_interval_units) == 0)) {
     sim_switches &= ~SWMASK ('T');
+    units = sim_vm_interval_units;
+    }
 else {
     int i;
     struct {
@@ -7042,6 +7048,7 @@ else {
         if (MATCH_CMD (gbuf, time_units[i].name) == 0) {
             sim_switches |= SWMASK ('T');
             usec_factor = time_units[i].usec_factor;
+            units = time_units[i].name;
             break;
             }
         }
@@ -7054,11 +7061,19 @@ sim_runlimit_enabled = TRUE;
 sim_cancel (&sim_runlimit_unit);
 sim_runlimit_switches = sim_switches;
 if (sim_runlimit_switches & SWMASK ('T')) {
-    sim_runlimit_d_initial = sim_runlimit_d = num * usec_factor;
+    sim_runlimit_d_initial = sim_runlimit_d = num * usec_factor * sim_host_speed_factor ();
+    if (sim_host_speed_factor () > 1.0)
+        sim_messagef (SCPE_OK, "Slow host - adjusting RUNLIMIT from %d %s to %.1f %s\n", num, units, num * sim_host_speed_factor (), units);
+    snprintf (runlimit, sizeof (runlimit), "%.f", num * sim_host_speed_factor ());
+    setenv ("SIM_RUNLIMIT", runlimit, 1);
+    setenv ("SIM_RUNLIMIT_UNITS", units, 1);
     return sim_activate_after_d (&sim_runlimit_unit, sim_runlimit_d);
     }
 else {
     sim_runlimit_initial = sim_runlimit = num;
+    snprintf (runlimit, sizeof (runlimit), "%d", num);
+    setenv ("SIM_RUNLIMIT", runlimit, 1);
+    setenv ("SIM_RUNLIMIT_UNITS", units, 1);
     return sim_activate (&sim_runlimit_unit, sim_runlimit);
     }
 }

sim_timer.c

@@ -3467,3 +3467,11 @@ for (tmr=0; tmr<=SIM_NTIMERS; tmr++) {
 sim_inst_per_sec_last = sim_precalibrate_ips;
 sim_idle_stable = 0;
 }
+
+double 
+sim_host_speed_factor (void)
+{
+if (sim_precalibrate_ips > SIM_INITIAL_IPS)
+    return 1.0;
+return (double)SIM_INITIAL_IPS / (double)sim_precalibrate_ips;
+}

sim_timer.h

@@ -158,6 +158,7 @@ t_stat sim_os_set_thread_priority (int below_normal_above);
 uint32 sim_get_rom_delay_factor (void);
 void sim_set_rom_delay_factor (uint32 delay);
 int32 sim_rom_read_with_delay (int32 val);
+double sim_host_speed_factor (void);
 
 extern t_bool sim_idle_enab;                        /* idle enabled flag */
 extern volatile t_bool sim_idle_wait;               /* idle waiting flag */