sim_timer.c - emulators/simh - Rivoreo Source Code Repositories

 /* sim_timer.c: simulator timer library

    Copyright (c) 1993-2008, Robert M Supnik

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the "Software"),
    to deal in the Software without restriction, including without limitation
    the rights to use, copy, modify, merge, publish, distribute, sublicense,
    and/or sell copies of the Software, and to permit persons to whom the
    Software is furnished to do so, subject to the following conditions:

    The above copyright notice and this permission notice shall be included in
    all copies or substantial portions of the Software.

    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
    ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
    IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
    CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

    Except as contained in this notice, the name of Robert M Supnik shall not be
    used in advertising or otherwise to promote the sale, use or other dealings
    in this Software without prior written authorization from Robert M Supnik.

    22-Sep-08    RMS     Added "stability threshold" for idle routine
    27-May-08    RMS     Fixed bug in Linux idle routines (from Walter Mueller)
    18-Jun-07    RMS     Modified idle to exclude counted delays
    22-Mar-07    RMS     Added sim_rtcn_init_all
    17-Oct-06    RMS     Added idle support (based on work by Mark Pizzolato)
                         Added throttle support
    16-Aug-05    RMS     Fixed C++ declaration and cast problems
    02-Jan-04    RMS     Split out from SCP

    This library includes the following routines:

    sim_timer_init -     initialize timing system
    sim_rtc_init -       initialize calibration
    sim_rtc_calb -       calibrate clock
    sim_timer_init -     initialize timing system
    sim_idle -           virtual machine idle
    sim_os_msec  -       return elapsed time in msec
    sim_os_sleep -       sleep specified number of seconds
    sim_os_ms_sleep -    sleep specified number of milliseconds

    The calibration, idle, and throttle routines are OS-independent; the _os_
    routines are not.
 */

 #include "sim_defs.h"
 #include <ctype.h>

 t_bool sim_idle_enab = FALSE;                           /* global flag */

 static uint32 sim_idle_rate_ms = 0;
 static uint32 sim_idle_stable = SIM_IDLE_STDFLT;
 static uint32 sim_throt_ms_start = 0;
 static uint32 sim_throt_ms_stop = 0;
 static uint32 sim_throt_type = 0;
 static uint32 sim_throt_val = 0;
 static uint32 sim_throt_state = 0;
 static int32 sim_throt_wait = 0;
 extern int32 sim_interval, sim_switches;
 extern FILE *sim_log;
 extern UNIT *sim_clock_queue;

 t_stat sim_throt_svc (UNIT *uptr);

 UNIT sim_throt_unit = { UDATA (&sim_throt_svc, 0, 0) };

 /* OS-dependent timer and clock routines */

 /* VMS */

 #if defined (VMS)

 #if defined (__VAX)
 #define sys$gettim SYS$GETTIM
 #endif

 #include <starlet.h>
 #include <lib$routines.h>
 #include <unistd.h>

 const t_bool rtc_avail = TRUE;

 uint32 sim_os_msec ()
 {
 uint32 quo, htod, tod[2];
 int32 i;

 sys$gettim (tod);                                       /* time 0.1usec */

 /* To convert to msec, must divide a 64b quantity by 10000.  This is actually done
    by dividing the 96b quantity 0'time by 10000, producing 64b of quotient, the
    high 32b of which are discarded.  This can probably be done by a clever multiply...
 */

 quo = htod = 0;
 for (i = 0; i < 64; i++) {                              /* 64b quo */
     htod = (htod << 1) | ((tod[1] >> 31) & 1);          /* shift divd */
     tod[1] = (tod[1] << 1) | ((tod[0] >> 31) & 1);
     tod[0] = tod[0] << 1;
     quo = quo << 1;                                     /* shift quo */
     if (htod >= 10000) {                                /* divd work? */
         htod = htod - 10000;                            /* subtract */
         quo = quo | 1;                                  /* set quo bit */
         }
     }
 return quo;
 }

 void sim_os_sleep (unsigned int sec)
 {
 sleep (sec);
 return;
 }

 uint32 sim_os_ms_sleep_init (void)
 {
 #if defined (__VAX)
 return 10;                                              /* VAX/VMS is 10ms */
 #else
 return 1;                                               /* Alpha/VMS is 1ms */
 #endif
 }

 uint32 sim_os_ms_sleep (unsigned int msec)
 {
 uint32 stime = sim_os_msec ();
 uint32 qtime[2];
 int32 nsfactor = -10000;
 static int32 zero = 0;

 lib$emul (&msec, &nsfactor, &zero, qtime);
 sys$setimr (2, qtime, 0, 0);
 sys$waitfr (2);
 return sim_os_msec () - stime;
 }

 /* Win32 routines */

 #elif defined (_WIN32)

 #include <windows.h>

 const t_bool rtc_avail = TRUE;

 uint32 sim_os_msec ()
 {
 if (sim_idle_rate_ms)
     return timeGetTime ();
 else return GetTickCount ();
 }

 void sim_os_sleep (unsigned int sec)
 {
 Sleep (sec * 1000);
 return;
 }

 void sim_timer_exit (void)
 {
 timeEndPeriod (sim_idle_rate_ms);
 return;
 }

 uint32 sim_os_ms_sleep_init (void)
 {
 TIMECAPS timers;

 if (timeGetDevCaps (&timers, sizeof (timers)) != TIMERR_NOERROR)
     return 0;
 if ((timers.wPeriodMin == 0) || (timers.wPeriodMin > SIM_IDLE_MAX))
     return 0;
 if (timeBeginPeriod (timers.wPeriodMin) != TIMERR_NOERROR)
     return 0;
 atexit (sim_timer_exit);
 Sleep (1);
 Sleep (1);
 Sleep (1);
 Sleep (1);
 Sleep (1);
 return timers.wPeriodMin;                               /* sim_idle_rate_ms */
 }

 uint32 sim_os_ms_sleep (unsigned int msec)
 {
 uint32 stime = sim_os_msec();

 Sleep (msec);
 return sim_os_msec () - stime;
 }

 /* OS/2 routines, from Bruce Ray */

 #elif defined (__OS2__)

 const t_bool rtc_avail = FALSE;

 uint32 sim_os_msec ()
 {
 return 0;
 }

 void sim_os_sleep (unsigned int sec)
 {
 return;
 }

 uint32 sim_os_ms_sleep_init (void)
 {
 return FALSE;
 }

 uint32 sim_os_ms_sleep (unsigned int msec)
 {
 return 0;
 }

 /* Metrowerks CodeWarrior Macintosh routines, from Ben Supnik */

 #elif defined (__MWERKS__) && defined (macintosh)

 #include <Timer.h>
 #include <Mactypes.h>
 #include <sioux.h>
 #include <unistd.h>
 #include <siouxglobals.h>
 #define NANOS_PER_MILLI     1000000
 #define MILLIS_PER_SEC      1000

 const t_bool rtc_avail = TRUE;

 uint32 sim_os_msec (void)
 {
 unsigned long long micros;
 UnsignedWide macMicros;
 unsigned long millis;

 Microseconds (&macMicros);
 micros = *((unsigned long long *) &macMicros);
 millis = micros / 1000LL;
 return (uint32) millis;
 }

 void sim_os_sleep (unsigned int sec)
 {
 sleep (sec);
 return;
 }

 uint32 sim_os_ms_sleep_init (void)
 {
 return 1;
 }

 uint32 sim_os_ms_sleep (unsigned int milliseconds)
 {
 uint32 stime = sim_os_msec ();
 struct timespec treq;

 treq.tv_sec = milliseconds / MILLIS_PER_SEC;
 treq.tv_nsec = (milliseconds % MILLIS_PER_SEC) * NANOS_PER_MILLI;
 (void) nanosleep (&treq, NULL);
 return sim_os_msec () - stime;
 }

 #else

 /* UNIX routines */

 #include <time.h>
 #include <sys/time.h>
 #include <unistd.h>
 #define NANOS_PER_MILLI     1000000
 #define MILLIS_PER_SEC      1000
 #define sleep1Samples       100

 const t_bool rtc_avail = TRUE;

 uint32 sim_os_msec ()
 {
 struct timeval cur;
 struct timezone foo;
 uint32 msec;

 gettimeofday (&cur, &foo);
 msec = (((uint32) cur.tv_sec) * 1000) + (((uint32) cur.tv_usec) / 1000);
 return msec;
 }

 void sim_os_sleep (unsigned int sec)
 {
 sleep (sec);
 return;
 }

 uint32 sim_os_ms_sleep_init (void)
 {
 #if defined (_POSIX_SOURCE)                              /* POSIX-compliant */

 struct timespec treq;
 uint32 msec;

 if (clock_getres (CLOCK_REALTIME, &treq) != 0)
     return 0;
 msec = (treq.tv_nsec + (NANOS_PER_MILLI - 1)) / NANOS_PER_MILLI;
 if (msec > SIM_IDLE_MAX) return 0;
 return msec;

 #else                                                   /* others */

 uint32 i, t1, t2, tot, tim;

 for (i = 0, tot = 0; i < sleep1Samples; i++) {
     t1 = sim_os_msec ();
     sim_os_ms_sleep (1);
     t2 = sim_os_msec ();
     tot += (t2 - t1);
     }
 tim = (tot + (sleep1Samples - 1)) / sleep1Samples;
 if (tim == 0)
     tim = 1;
 else if (tim > SIM_IDLE_MAX)
     tim = 0;
 return tim;

 #endif
 }

 uint32 sim_os_ms_sleep (unsigned int milliseconds)
 {
 uint32 stime = sim_os_msec ();
 struct timespec treq;

 treq.tv_sec = milliseconds / MILLIS_PER_SEC;
 treq.tv_nsec = (milliseconds % MILLIS_PER_SEC) * NANOS_PER_MILLI;
 (void) nanosleep (&treq, NULL);
 return sim_os_msec () - stime;
 }

 #endif

 /* OS independent clock calibration package */

 static int32 rtc_ticks[SIM_NTIMERS] = { 0 };            /* ticks */
 static int32 rtc_hz[SIM_NTIMERS] = { 0 };               /* tick rate */
 static uint32 rtc_rtime[SIM_NTIMERS] = { 0 };           /* real time */
 static uint32 rtc_vtime[SIM_NTIMERS] = { 0 };           /* virtual time */
 static uint32 rtc_nxintv[SIM_NTIMERS] = { 0 };          /* next interval */
 static int32 rtc_based[SIM_NTIMERS] = { 0 };            /* base delay */
 static int32 rtc_currd[SIM_NTIMERS] = { 0 };            /* current delay */
 static int32 rtc_initd[SIM_NTIMERS] = { 0 };            /* initial delay */
 static uint32 rtc_elapsed[SIM_NTIMERS] = { 0 };         /* sec since init */

 void sim_rtcn_init_all (void)
 {
 uint32 i;

 for (i = 0; i < SIM_NTIMERS; i++) {
     if (rtc_initd[i] != 0) sim_rtcn_init (rtc_initd[i], i);
     }
 return;
 }

 int32 sim_rtcn_init (int32 time, int32 tmr)
 {
 if (time == 0)
     time = 1;
 if ((tmr < 0) || (tmr >= SIM_NTIMERS))
     return time;
 rtc_rtime[tmr] = sim_os_msec ();
 rtc_vtime[tmr] = rtc_rtime[tmr];
 rtc_nxintv[tmr] = 1000;
 rtc_ticks[tmr] = 0;
 rtc_hz[tmr] = 0;
 rtc_based[tmr] = time;
 rtc_currd[tmr] = time;
 rtc_initd[tmr] = time;
 rtc_elapsed[tmr] = 0;
 return time;
 }

 int32 sim_rtcn_calb (int32 ticksper, int32 tmr)
 {
 uint32 new_rtime, delta_rtime;
 int32 delta_vtime;

 if ((tmr < 0) || (tmr >= SIM_NTIMERS))
     return 10000;
 rtc_hz[tmr] = ticksper;
 rtc_ticks[tmr] = rtc_ticks[tmr] + 1;                    /* count ticks */
 if (rtc_ticks[tmr] < ticksper)                          /* 1 sec yet? */
     return rtc_currd[tmr];
 rtc_ticks[tmr] = 0;                                     /* reset ticks */
 rtc_elapsed[tmr] = rtc_elapsed[tmr] + 1;                /* count sec */
 if (!rtc_avail)                                         /* no timer? */
     return rtc_currd[tmr];
 new_rtime = sim_os_msec ();                             /* wall time */
 if (new_rtime < rtc_rtime[tmr]) {                       /* time running backwards? */
     rtc_rtime[tmr] = new_rtime;                         /* reset wall time */
     return rtc_currd[tmr];                              /* can't calibrate */
     }
 delta_rtime = new_rtime - rtc_rtime[tmr];               /* elapsed wtime */
 rtc_rtime[tmr] = new_rtime;                             /* adv wall time */
 rtc_vtime[tmr] = rtc_vtime[tmr] + 1000;                 /* adv sim time */
 if (delta_rtime > 30000)                                /* gap too big? */
     return rtc_initd[tmr];                              /* can't calibr */
 if (delta_rtime == 0)                                   /* gap too small? */
     rtc_based[tmr] = rtc_based[tmr] * ticksper;         /* slew wide */
 else rtc_based[tmr] = (int32) (((double) rtc_based[tmr] * (double) rtc_nxintv[tmr]) /
     ((double) delta_rtime));                            /* new base rate */
 delta_vtime = rtc_vtime[tmr] - rtc_rtime[tmr];          /* gap */
 if (delta_vtime > SIM_TMAX)                             /* limit gap */
     delta_vtime = SIM_TMAX;
 else if (delta_vtime < -SIM_TMAX)
     delta_vtime = -SIM_TMAX;
 rtc_nxintv[tmr] = 1000 + delta_vtime;                   /* next wtime */
 rtc_currd[tmr] = (int32) (((double) rtc_based[tmr] * (double) rtc_nxintv[tmr]) /
     1000.0);                                            /* next delay */
 if (rtc_based[tmr] <= 0)                                /* never negative or zero! */
     rtc_based[tmr] = 1;
 if (rtc_currd[tmr] <= 0)                                /* never negative or zero! */
     rtc_currd[tmr] = 1;
 return rtc_currd[tmr];
 }

 /* Prior interfaces - default to timer 0 */

 int32 sim_rtc_init (int32 time)
 {
 return sim_rtcn_init (time, 0);
 }

 int32 sim_rtc_calb (int32 ticksper)
 {
 return sim_rtcn_calb (ticksper, 0);
 }

 /* sim_timer_init - get minimum sleep time available on this host */

 t_bool sim_timer_init (void)
 {
 sim_idle_enab = FALSE;                                  /* init idle off */
 sim_idle_rate_ms = sim_os_ms_sleep_init ();             /* get OS timer rate */
 return (sim_idle_rate_ms != 0);
 }

 /* sim_idle - idle simulator until next event or for specified interval

    Inputs:
         tmr =   calibrated timer to use

    Must solve the linear equation

         ms_to_wait = w * ms_per_wait

    Or
         w = ms_to_wait / ms_per_wait
 */

 t_bool sim_idle (uint32 tmr, t_bool sin_cyc)
 {
 uint32 cyc_ms, w_ms, w_idle, act_ms;
 int32 act_cyc;

 if ((sim_clock_queue == NULL) ||                        /* clock queue empty? */
     ((sim_clock_queue->flags & UNIT_IDLE) == 0) ||      /* event not idle-able? */
     (rtc_elapsed[tmr] < sim_idle_stable)) {             /* timer not stable? */
     if (sin_cyc)
         sim_interval = sim_interval - 1;
     return FALSE;
     }
 cyc_ms = (rtc_currd[tmr] * rtc_hz[tmr]) / 1000;         /* cycles per msec */
 if ((sim_idle_rate_ms == 0) || (cyc_ms == 0)) {         /* not possible? */
     if (sin_cyc)
         sim_interval = sim_interval - 1;
     return FALSE;
     }
 w_ms = (uint32) sim_interval / cyc_ms;                  /* ms to wait */
 w_idle = w_ms / sim_idle_rate_ms;                       /* intervals to wait */
 if (w_idle == 0) {                                      /* none? */
     if (sin_cyc)
         sim_interval = sim_interval - 1;
     return FALSE;
     }
 act_ms = sim_os_ms_sleep (w_idle);                      /* wait */
 act_cyc = act_ms * cyc_ms;
 if (sim_interval > act_cyc)
     sim_interval = sim_interval - act_cyc;
 else sim_interval = 1;
 return TRUE;
 }

 /* Set idling - implicitly disables throttling */

 t_stat sim_set_idle (UNIT *uptr, int32 val, char *cptr, void *desc)
 {
 t_stat r;
 uint32 v;

 if (sim_idle_rate_ms == 0)
     return SCPE_NOFNC;
 if ((val != 0) && (sim_idle_rate_ms > (uint32) val))
     return SCPE_NOFNC;
 if (cptr) {
     v = (uint32) get_uint (cptr, 10, SIM_IDLE_STMAX, &r);
     if ((r != SCPE_OK) || (v < SIM_IDLE_STMIN))
         return SCPE_ARG;
     sim_idle_stable = v;
     }
 sim_idle_enab = TRUE;
 if (sim_throt_type != SIM_THROT_NONE) {
     sim_set_throt (0, NULL);
     printf ("Throttling disabled\n");
     if (sim_log)
         fprintf (sim_log, "Throttling disabled\n");
     }
 return SCPE_OK;
 }

 /* Clear idling */

 t_stat sim_clr_idle (UNIT *uptr, int32 val, char *cptr, void *desc)
 {
 sim_idle_enab = FALSE;
 return SCPE_OK;
 }

 /* Show idling */

 t_stat sim_show_idle (FILE *st, UNIT *uptr, int32 val, void *desc)
 {
 if (sim_idle_enab)
     fprintf (st, "idle enabled, stability wait = %ds", sim_idle_stable);
 else fputs ("idle disabled", st);
 return SCPE_OK;
 }

 /* Throttling package */

 t_stat sim_set_throt (int32 arg, char *cptr)
 {
 char *tptr, c;
 t_value val;

 if (arg == 0) {
     if ((cptr != 0) && (*cptr != 0))
         return SCPE_ARG;
     sim_throt_type = SIM_THROT_NONE;
     sim_throt_cancel ();
     }
 else if (sim_idle_rate_ms == 0)
     return SCPE_NOFNC;
 else {
     val = strtotv (cptr, &tptr, 10);
     if (cptr == tptr)
         return SCPE_ARG;
     c = toupper (*tptr++);
     if (*tptr != 0)
         return SCPE_ARG;
     if (c == 'M')
         sim_throt_type = SIM_THROT_MCYC;
     else if (c == 'K')
         sim_throt_type = SIM_THROT_KCYC;
     else if ((c == '%') && (val > 0) && (val < 100))
         sim_throt_type = SIM_THROT_PCT;
     else return SCPE_ARG;
     if (sim_idle_enab) {
         printf ("Idling disabled\n");
         if (sim_log)
             fprintf (sim_log, "Idling disabled\n");
         sim_clr_idle (NULL, 0, NULL, NULL);
         }
     sim_throt_val = (uint32) val;
     }
 return SCPE_OK;
 }

 t_stat sim_show_throt (FILE *st, DEVICE *dnotused, UNIT *unotused, int32 flag, char *cptr)
 {
 if (sim_idle_rate_ms == 0)
     fprintf (st, "Throttling not available\n");
 else {
     switch (sim_throt_type) {

     case SIM_THROT_MCYC:
         fprintf (st, "Throttle = %d megacycles\n", sim_throt_val);
         break;

     case SIM_THROT_KCYC:
         fprintf (st, "Throttle = %d kilocycles\n", sim_throt_val);
         break;

     case SIM_THROT_PCT:
         fprintf (st, "Throttle = %d%%\n", sim_throt_val);
         break;

     default:
         fprintf (st, "Throttling disabled\n");
         break;
         }

     if (sim_switches & SWMASK ('D')) {
         fprintf (st, "Wait rate = %d ms\n", sim_idle_rate_ms);
         if (sim_throt_type != 0)
             fprintf (st, "Throttle interval = %d cycles\n", sim_throt_wait);
         }
     }
 return SCPE_OK;
 }

 void sim_throt_sched (void)
 {
 sim_throt_state = 0;
 if (sim_throt_type)
     sim_activate (&sim_throt_unit, SIM_THROT_WINIT);
 return;
 }

 void sim_throt_cancel (void)
 {
 sim_cancel (&sim_throt_unit);
 }

 /* Throttle service

    Throttle service has three distinct states

    0        take initial measurement
    1        take final measurement, calculate wait values
    2        periodic waits to slow down the CPU
 */

 t_stat sim_throt_svc (UNIT *uptr)
 {
 uint32 delta_ms;
 double a_cps, d_cps;

 switch (sim_throt_state) {

     case 0:                                             /* take initial reading */
         sim_throt_ms_start = sim_os_msec ();
         sim_throt_wait = SIM_THROT_WST;
         sim_throt_state++;                              /* next state */
         break;                                          /* reschedule */

     case 1:                                             /* take final reading */
         sim_throt_ms_stop = sim_os_msec ();
         delta_ms = sim_throt_ms_stop - sim_throt_ms_start;
         if (delta_ms < SIM_THROT_MSMIN) {               /* not enough time? */
             if (sim_throt_wait >= 100000000) {          /* too many inst? */
                 sim_throt_state = 0;                    /* fails in 32b! */
                 return SCPE_OK;
                 }
             sim_throt_wait = sim_throt_wait * SIM_THROT_WMUL;
             sim_throt_ms_start = sim_throt_ms_stop;
             }
         else {                                          /* long enough */
             a_cps = ((double) sim_throt_wait) * 1000.0 / (double) delta_ms;
             if (sim_throt_type == SIM_THROT_MCYC)       /* calc desired cps */
                 d_cps = (double) sim_throt_val * 1000000.0;
             else if (sim_throt_type == SIM_THROT_KCYC)
                 d_cps = (double) sim_throt_val * 1000.0;
             else d_cps = (a_cps * ((double) sim_throt_val)) / 100.0;
             if (d_cps >= a_cps) {
                 sim_throt_state = 0;
                 return SCPE_OK;
                 }
             sim_throt_wait = (int32)                    /* time between waits */
                 ((a_cps * d_cps * ((double) sim_idle_rate_ms)) /
                  (1000.0 * (a_cps - d_cps)));
             if (sim_throt_wait < SIM_THROT_WMIN) {      /* not long enough? */
                 sim_throt_state = 0;
                 return SCPE_OK;
                 }
             sim_throt_state++;
 //            fprintf (stderr, "Throttle values a_cps = %f, d_cps = %f, wait = %d\n",
 //                a_cps, d_cps, sim_throt_wait);
             }
         break;

     case 2:                                             /* throttling */
         sim_os_ms_sleep (1);
         break;
         }

 sim_activate (uptr, sim_throt_wait);                    /* reschedule */
 return SCPE_OK;
 }
	/* sim_timer.c: simulator timer library

	Copyright (c) 1993-2008, Robert M Supnik

	Permission is hereby granted, free of charge, to any person obtaining a
	copy of this software and associated documentation files (the "Software"),
	to deal in the Software without restriction, including without limitation
	the rights to use, copy, modify, merge, publish, distribute, sublicense,
	and/or sell copies of the Software, and to permit persons to whom the
	Software is furnished to do so, subject to the following conditions:

	The above copyright notice and this permission notice shall be included in
	all copies or substantial portions of the Software.

	THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	ROBERT M SUPNIK BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
	IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
	CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

	Except as contained in this notice, the name of Robert M Supnik shall not be
	used in advertising or otherwise to promote the sale, use or other dealings
	in this Software without prior written authorization from Robert M Supnik.

	22-Sep-08 RMS Added "stability threshold" for idle routine
	27-May-08 RMS Fixed bug in Linux idle routines (from Walter Mueller)
	18-Jun-07 RMS Modified idle to exclude counted delays
	22-Mar-07 RMS Added sim_rtcn_init_all
	17-Oct-06 RMS Added idle support (based on work by Mark Pizzolato)
	Added throttle support
	16-Aug-05 RMS Fixed C++ declaration and cast problems
	02-Jan-04 RMS Split out from SCP

	This library includes the following routines:

	sim_timer_init - initialize timing system
	sim_rtc_init - initialize calibration
	sim_rtc_calb - calibrate clock
	sim_timer_init - initialize timing system
	sim_idle - virtual machine idle
	sim_os_msec - return elapsed time in msec
	sim_os_sleep - sleep specified number of seconds
	sim_os_ms_sleep - sleep specified number of milliseconds

	The calibration, idle, and throttle routines are OS-independent; the _os_
	routines are not.
	*/

	#include "sim_defs.h"
	#include <ctype.h>

	t_bool sim_idle_enab = FALSE; /* global flag */

	static uint32 sim_idle_rate_ms = 0;
	static uint32 sim_idle_stable = SIM_IDLE_STDFLT;
	static uint32 sim_throt_ms_start = 0;
	static uint32 sim_throt_ms_stop = 0;
	static uint32 sim_throt_type = 0;
	static uint32 sim_throt_val = 0;
	static uint32 sim_throt_state = 0;
	static int32 sim_throt_wait = 0;
	extern int32 sim_interval, sim_switches;
	extern FILE *sim_log;
	extern UNIT *sim_clock_queue;

	t_stat sim_throt_svc (UNIT *uptr);

	UNIT sim_throt_unit = { UDATA (&sim_throt_svc, 0, 0) };

	/* OS-dependent timer and clock routines */

	/* VMS */

	#if defined (VMS)

	#if defined (__VAX)
	#define sys$gettim SYS$GETTIM
	#endif

	#include <starlet.h>
	#include <lib$routines.h>
	#include <unistd.h>

	const t_bool rtc_avail = TRUE;

	uint32 sim_os_msec ()
	{
	uint32 quo, htod, tod[2];
	int32 i;

	sys$gettim (tod); /* time 0.1usec */

	/* To convert to msec, must divide a 64b quantity by 10000. This is actually done
	by dividing the 96b quantity 0'time by 10000, producing 64b of quotient, the
	high 32b of which are discarded. This can probably be done by a clever multiply...
	*/

	quo = htod = 0;
	for (i = 0; i < 64; i++) { /* 64b quo */
	htod = (htod << 1) \| ((tod[1] >> 31) & 1); /* shift divd */
	tod[1] = (tod[1] << 1) \| ((tod[0] >> 31) & 1);
	tod[0] = tod[0] << 1;
	quo = quo << 1; /* shift quo */
	if (htod >= 10000) { /* divd work? */
	htod = htod - 10000; /* subtract */
	quo = quo \| 1; /* set quo bit */
	}
	}
	return quo;
	}

	void sim_os_sleep (unsigned int sec)
	{
	sleep (sec);
	return;
	}

	uint32 sim_os_ms_sleep_init (void)
	{
	#if defined (__VAX)
	return 10; /* VAX/VMS is 10ms */
	#else
	return 1; /* Alpha/VMS is 1ms */
	#endif
	}

	uint32 sim_os_ms_sleep (unsigned int msec)
	{
	uint32 stime = sim_os_msec ();
	uint32 qtime[2];
	int32 nsfactor = -10000;
	static int32 zero = 0;

	lib$emul (&msec, &nsfactor, &zero, qtime);
	sys$setimr (2, qtime, 0, 0);
	sys$waitfr (2);
	return sim_os_msec () - stime;
	}

	/* Win32 routines */

	#elif defined (_WIN32)

	#include <windows.h>

	const t_bool rtc_avail = TRUE;

	uint32 sim_os_msec ()
	{
	if (sim_idle_rate_ms)
	return timeGetTime ();
	else return GetTickCount ();
	}

	void sim_os_sleep (unsigned int sec)
	{
	Sleep (sec * 1000);
	return;
	}

	void sim_timer_exit (void)
	{
	timeEndPeriod (sim_idle_rate_ms);
	return;
	}

	uint32 sim_os_ms_sleep_init (void)
	{
	TIMECAPS timers;

	if (timeGetDevCaps (&timers, sizeof (timers)) != TIMERR_NOERROR)
	return 0;
	if ((timers.wPeriodMin == 0) \|\| (timers.wPeriodMin > SIM_IDLE_MAX))
	return 0;
	if (timeBeginPeriod (timers.wPeriodMin) != TIMERR_NOERROR)
	return 0;
	atexit (sim_timer_exit);
	Sleep (1);
	Sleep (1);
	Sleep (1);
	Sleep (1);
	Sleep (1);
	return timers.wPeriodMin; /* sim_idle_rate_ms */
	}

	uint32 sim_os_ms_sleep (unsigned int msec)
	{
	uint32 stime = sim_os_msec();

	Sleep (msec);
	return sim_os_msec () - stime;
	}

	/* OS/2 routines, from Bruce Ray */

	#elif defined (__OS2__)

	const t_bool rtc_avail = FALSE;

	uint32 sim_os_msec ()
	{
	return 0;
	}

	void sim_os_sleep (unsigned int sec)
	{
	return;
	}

	uint32 sim_os_ms_sleep_init (void)
	{
	return FALSE;
	}

	uint32 sim_os_ms_sleep (unsigned int msec)
	{
	return 0;
	}

	/* Metrowerks CodeWarrior Macintosh routines, from Ben Supnik */

	#elif defined (__MWERKS__) && defined (macintosh)

	#include <Timer.h>
	#include <Mactypes.h>
	#include <sioux.h>
	#include <unistd.h>
	#include <siouxglobals.h>
	#define NANOS_PER_MILLI 1000000
	#define MILLIS_PER_SEC 1000

	const t_bool rtc_avail = TRUE;

	uint32 sim_os_msec (void)
	{
	unsigned long long micros;
	UnsignedWide macMicros;
	unsigned long millis;

	Microseconds (&macMicros);
	micros = ((unsigned long long ) &macMicros);
	millis = micros / 1000LL;
	return (uint32) millis;
	}

	void sim_os_sleep (unsigned int sec)
	{
	sleep (sec);
	return;
	}

	uint32 sim_os_ms_sleep_init (void)
	{
	return 1;
	}

	uint32 sim_os_ms_sleep (unsigned int milliseconds)
	{
	uint32 stime = sim_os_msec ();
	struct timespec treq;

	treq.tv_sec = milliseconds / MILLIS_PER_SEC;
	treq.tv_nsec = (milliseconds % MILLIS_PER_SEC) * NANOS_PER_MILLI;
	(void) nanosleep (&treq, NULL);
	return sim_os_msec () - stime;
	}

	#else

	/* UNIX routines */

	#include <time.h>
	#include <sys/time.h>
	#include <unistd.h>
	#define NANOS_PER_MILLI 1000000
	#define MILLIS_PER_SEC 1000
	#define sleep1Samples 100

	const t_bool rtc_avail = TRUE;

	uint32 sim_os_msec ()
	{
	struct timeval cur;
	struct timezone foo;
	uint32 msec;

	gettimeofday (&cur, &foo);
	msec = (((uint32) cur.tv_sec) * 1000) + (((uint32) cur.tv_usec) / 1000);
	return msec;
	}

	void sim_os_sleep (unsigned int sec)
	{
	sleep (sec);
	return;
	}

	uint32 sim_os_ms_sleep_init (void)
	{
	#if defined (_POSIX_SOURCE) /* POSIX-compliant */

	struct timespec treq;
	uint32 msec;

	if (clock_getres (CLOCK_REALTIME, &treq) != 0)
	return 0;
	msec = (treq.tv_nsec + (NANOS_PER_MILLI - 1)) / NANOS_PER_MILLI;
	if (msec > SIM_IDLE_MAX) return 0;
	return msec;

	#else /* others */

	uint32 i, t1, t2, tot, tim;

	for (i = 0, tot = 0; i < sleep1Samples; i++) {
	t1 = sim_os_msec ();
	sim_os_ms_sleep (1);
	t2 = sim_os_msec ();
	tot += (t2 - t1);
	}
	tim = (tot + (sleep1Samples - 1)) / sleep1Samples;
	if (tim == 0)
	tim = 1;
	else if (tim > SIM_IDLE_MAX)
	tim = 0;
	return tim;

	#endif
	}

	uint32 sim_os_ms_sleep (unsigned int milliseconds)
	{
	uint32 stime = sim_os_msec ();
	struct timespec treq;

	treq.tv_sec = milliseconds / MILLIS_PER_SEC;
	treq.tv_nsec = (milliseconds % MILLIS_PER_SEC) * NANOS_PER_MILLI;
	(void) nanosleep (&treq, NULL);
	return sim_os_msec () - stime;
	}

	#endif

	/* OS independent clock calibration package */

	static int32 rtc_ticks[SIM_NTIMERS] = { 0 }; /* ticks */
	static int32 rtc_hz[SIM_NTIMERS] = { 0 }; /* tick rate */
	static uint32 rtc_rtime[SIM_NTIMERS] = { 0 }; /* real time */
	static uint32 rtc_vtime[SIM_NTIMERS] = { 0 }; /* virtual time */
	static uint32 rtc_nxintv[SIM_NTIMERS] = { 0 }; /* next interval */
	static int32 rtc_based[SIM_NTIMERS] = { 0 }; /* base delay */
	static int32 rtc_currd[SIM_NTIMERS] = { 0 }; /* current delay */
	static int32 rtc_initd[SIM_NTIMERS] = { 0 }; /* initial delay */
	static uint32 rtc_elapsed[SIM_NTIMERS] = { 0 }; /* sec since init */

	void sim_rtcn_init_all (void)
	{
	uint32 i;

	for (i = 0; i < SIM_NTIMERS; i++) {
	if (rtc_initd[i] != 0) sim_rtcn_init (rtc_initd[i], i);
	}
	return;
	}

	int32 sim_rtcn_init (int32 time, int32 tmr)
	{
	if (time == 0)
	time = 1;
	if ((tmr < 0) \|\| (tmr >= SIM_NTIMERS))
	return time;
	rtc_rtime[tmr] = sim_os_msec ();
	rtc_vtime[tmr] = rtc_rtime[tmr];
	rtc_nxintv[tmr] = 1000;
	rtc_ticks[tmr] = 0;
	rtc_hz[tmr] = 0;
	rtc_based[tmr] = time;
	rtc_currd[tmr] = time;
	rtc_initd[tmr] = time;
	rtc_elapsed[tmr] = 0;
	return time;
	}

	int32 sim_rtcn_calb (int32 ticksper, int32 tmr)
	{
	uint32 new_rtime, delta_rtime;
	int32 delta_vtime;

	if ((tmr < 0) \|\| (tmr >= SIM_NTIMERS))
	return 10000;
	rtc_hz[tmr] = ticksper;
	rtc_ticks[tmr] = rtc_ticks[tmr] + 1; /* count ticks */
	if (rtc_ticks[tmr] < ticksper) /* 1 sec yet? */
	return rtc_currd[tmr];
	rtc_ticks[tmr] = 0; /* reset ticks */
	rtc_elapsed[tmr] = rtc_elapsed[tmr] + 1; /* count sec */
	if (!rtc_avail) /* no timer? */
	return rtc_currd[tmr];
	new_rtime = sim_os_msec (); /* wall time */
	if (new_rtime < rtc_rtime[tmr]) { /* time running backwards? */
	rtc_rtime[tmr] = new_rtime; /* reset wall time */
	return rtc_currd[tmr]; /* can't calibrate */
	}
	delta_rtime = new_rtime - rtc_rtime[tmr]; /* elapsed wtime */
	rtc_rtime[tmr] = new_rtime; /* adv wall time */
	rtc_vtime[tmr] = rtc_vtime[tmr] + 1000; /* adv sim time */
	if (delta_rtime > 30000) /* gap too big? */
	return rtc_initd[tmr]; /* can't calibr */
	if (delta_rtime == 0) /* gap too small? */
	rtc_based[tmr] = rtc_based[tmr] * ticksper; /* slew wide */
	else rtc_based[tmr] = (int32) (((double) rtc_based[tmr] * (double) rtc_nxintv[tmr]) /
	((double) delta_rtime)); /* new base rate */
	delta_vtime = rtc_vtime[tmr] - rtc_rtime[tmr]; /* gap */
	if (delta_vtime > SIM_TMAX) /* limit gap */
	delta_vtime = SIM_TMAX;
	else if (delta_vtime < -SIM_TMAX)
	delta_vtime = -SIM_TMAX;
	rtc_nxintv[tmr] = 1000 + delta_vtime; /* next wtime */
	rtc_currd[tmr] = (int32) (((double) rtc_based[tmr] * (double) rtc_nxintv[tmr]) /
	1000.0); /* next delay */
	if (rtc_based[tmr] <= 0) /* never negative or zero! */
	rtc_based[tmr] = 1;
	if (rtc_currd[tmr] <= 0) /* never negative or zero! */
	rtc_currd[tmr] = 1;
	return rtc_currd[tmr];
	}

	/* Prior interfaces - default to timer 0 */

	int32 sim_rtc_init (int32 time)
	{
	return sim_rtcn_init (time, 0);
	}

	int32 sim_rtc_calb (int32 ticksper)
	{
	return sim_rtcn_calb (ticksper, 0);
	}

	/* sim_timer_init - get minimum sleep time available on this host */

	t_bool sim_timer_init (void)
	{
	sim_idle_enab = FALSE; /* init idle off */
	sim_idle_rate_ms = sim_os_ms_sleep_init (); /* get OS timer rate */
	return (sim_idle_rate_ms != 0);
	}

	/* sim_idle - idle simulator until next event or for specified interval

	Inputs:
	tmr = calibrated timer to use

	Must solve the linear equation

	ms_to_wait = w * ms_per_wait

	Or
	w = ms_to_wait / ms_per_wait
	*/

	t_bool sim_idle (uint32 tmr, t_bool sin_cyc)
	{
	uint32 cyc_ms, w_ms, w_idle, act_ms;
	int32 act_cyc;

	if ((sim_clock_queue == NULL) \|\| /* clock queue empty? */
	((sim_clock_queue->flags & UNIT_IDLE) == 0) \|\| /* event not idle-able? */
	(rtc_elapsed[tmr] < sim_idle_stable)) { /* timer not stable? */
	if (sin_cyc)
	sim_interval = sim_interval - 1;
	return FALSE;
	}
	cyc_ms = (rtc_currd[tmr] * rtc_hz[tmr]) / 1000; /* cycles per msec */
	if ((sim_idle_rate_ms == 0) \|\| (cyc_ms == 0)) { /* not possible? */
	if (sin_cyc)
	sim_interval = sim_interval - 1;
	return FALSE;
	}
	w_ms = (uint32) sim_interval / cyc_ms; /* ms to wait */
	w_idle = w_ms / sim_idle_rate_ms; /* intervals to wait */
	if (w_idle == 0) { /* none? */
	if (sin_cyc)
	sim_interval = sim_interval - 1;
	return FALSE;
	}
	act_ms = sim_os_ms_sleep (w_idle); /* wait */
	act_cyc = act_ms * cyc_ms;
	if (sim_interval > act_cyc)
	sim_interval = sim_interval - act_cyc;
	else sim_interval = 1;
	return TRUE;
	}

	/* Set idling - implicitly disables throttling */

	t_stat sim_set_idle (UNIT uptr, int32 val, char cptr, void *desc)
	{
	t_stat r;
	uint32 v;

	if (sim_idle_rate_ms == 0)
	return SCPE_NOFNC;
	if ((val != 0) && (sim_idle_rate_ms > (uint32) val))
	return SCPE_NOFNC;
	if (cptr) {
	v = (uint32) get_uint (cptr, 10, SIM_IDLE_STMAX, &r);
	if ((r != SCPE_OK) \|\| (v < SIM_IDLE_STMIN))
	return SCPE_ARG;
	sim_idle_stable = v;
	}
	sim_idle_enab = TRUE;
	if (sim_throt_type != SIM_THROT_NONE) {
	sim_set_throt (0, NULL);
	printf ("Throttling disabled\n");
	if (sim_log)
	fprintf (sim_log, "Throttling disabled\n");
	}
	return SCPE_OK;
	}

	/* Clear idling */

	t_stat sim_clr_idle (UNIT uptr, int32 val, char cptr, void *desc)
	{
	sim_idle_enab = FALSE;
	return SCPE_OK;
	}

	/* Show idling */

	t_stat sim_show_idle (FILE st, UNIT uptr, int32 val, void *desc)
	{
	if (sim_idle_enab)
	fprintf (st, "idle enabled, stability wait = %ds", sim_idle_stable);
	else fputs ("idle disabled", st);
	return SCPE_OK;
	}

	/* Throttling package */

	t_stat sim_set_throt (int32 arg, char *cptr)
	{
	char *tptr, c;
	t_value val;

	if (arg == 0) {
	if ((cptr != 0) && (*cptr != 0))
	return SCPE_ARG;
	sim_throt_type = SIM_THROT_NONE;
	sim_throt_cancel ();
	}
	else if (sim_idle_rate_ms == 0)
	return SCPE_NOFNC;
	else {
	val = strtotv (cptr, &tptr, 10);
	if (cptr == tptr)
	return SCPE_ARG;
	c = toupper (*tptr++);
	if (*tptr != 0)
	return SCPE_ARG;
	if (c == 'M')
	sim_throt_type = SIM_THROT_MCYC;
	else if (c == 'K')
	sim_throt_type = SIM_THROT_KCYC;
	else if ((c == '%') && (val > 0) && (val < 100))
	sim_throt_type = SIM_THROT_PCT;
	else return SCPE_ARG;
	if (sim_idle_enab) {
	printf ("Idling disabled\n");
	if (sim_log)
	fprintf (sim_log, "Idling disabled\n");
	sim_clr_idle (NULL, 0, NULL, NULL);
	}
	sim_throt_val = (uint32) val;
	}
	return SCPE_OK;
	}

	t_stat sim_show_throt (FILE st, DEVICE dnotused, UNIT unotused, int32 flag, char cptr)
	{
	if (sim_idle_rate_ms == 0)
	fprintf (st, "Throttling not available\n");
	else {
	switch (sim_throt_type) {

	case SIM_THROT_MCYC:
	fprintf (st, "Throttle = %d megacycles\n", sim_throt_val);
	break;

	case SIM_THROT_KCYC:
	fprintf (st, "Throttle = %d kilocycles\n", sim_throt_val);
	break;

	case SIM_THROT_PCT:
	fprintf (st, "Throttle = %d%%\n", sim_throt_val);
	break;

	default:
	fprintf (st, "Throttling disabled\n");
	break;
	}

	if (sim_switches & SWMASK ('D')) {
	fprintf (st, "Wait rate = %d ms\n", sim_idle_rate_ms);
	if (sim_throt_type != 0)
	fprintf (st, "Throttle interval = %d cycles\n", sim_throt_wait);
	}
	}
	return SCPE_OK;
	}

	void sim_throt_sched (void)
	{
	sim_throt_state = 0;
	if (sim_throt_type)
	sim_activate (&sim_throt_unit, SIM_THROT_WINIT);
	return;
	}

	void sim_throt_cancel (void)
	{
	sim_cancel (&sim_throt_unit);
	}

	/* Throttle service

	Throttle service has three distinct states

	0 take initial measurement
	1 take final measurement, calculate wait values
	2 periodic waits to slow down the CPU
	*/

	t_stat sim_throt_svc (UNIT *uptr)
	{
	uint32 delta_ms;
	double a_cps, d_cps;

	switch (sim_throt_state) {

	case 0: /* take initial reading */
	sim_throt_ms_start = sim_os_msec ();
	sim_throt_wait = SIM_THROT_WST;
	sim_throt_state++; /* next state */
	break; /* reschedule */

	case 1: /* take final reading */
	sim_throt_ms_stop = sim_os_msec ();
	delta_ms = sim_throt_ms_stop - sim_throt_ms_start;
	if (delta_ms < SIM_THROT_MSMIN) { /* not enough time? */
	if (sim_throt_wait >= 100000000) { /* too many inst? */
	sim_throt_state = 0; /* fails in 32b! */
	return SCPE_OK;
	}
	sim_throt_wait = sim_throt_wait * SIM_THROT_WMUL;
	sim_throt_ms_start = sim_throt_ms_stop;
	}
	else { /* long enough */
	a_cps = ((double) sim_throt_wait) * 1000.0 / (double) delta_ms;
	if (sim_throt_type == SIM_THROT_MCYC) /* calc desired cps */
	d_cps = (double) sim_throt_val * 1000000.0;
	else if (sim_throt_type == SIM_THROT_KCYC)
	d_cps = (double) sim_throt_val * 1000.0;
	else d_cps = (a_cps * ((double) sim_throt_val)) / 100.0;
	if (d_cps >= a_cps) {
	sim_throt_state = 0;
	return SCPE_OK;
	}
	sim_throt_wait = (int32) /* time between waits */
	((a_cps * d_cps * ((double) sim_idle_rate_ms)) /
	(1000.0 * (a_cps - d_cps)));
	if (sim_throt_wait < SIM_THROT_WMIN) { /* not long enough? */
	sim_throt_state = 0;
	return SCPE_OK;
	}
	sim_throt_state++;
	// fprintf (stderr, "Throttle values a_cps = %f, d_cps = %f, wait = %d\n",
	// a_cps, d_cps, sim_throt_wait);
	}
	break;

	case 2: /* throttling */
	sim_os_ms_sleep (1);
	break;
	}

	sim_activate (uptr, sim_throt_wait); /* reschedule */
	return SCPE_OK;
	}