sim/ppc/events.c

   1 /*  This file is part of the program psim.
   2
   3     Copyright (C) 1994-1998, Andrew Cagney <cagney@highland.com.au>
   4
   5     This program is free software; you can redistribute it and/or modify
   6     it under the terms of the GNU General Public License as published by
   7     the Free Software Foundation; either version 3 of the License, or
   8     (at your option) any later version.
   9
  10     This program is distributed in the hope that it will be useful,
  11     but WITHOUT ANY WARRANTY; without even the implied warranty of
  12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13     GNU General Public License for more details.
  14
  15     You should have received a copy of the GNU General Public License
  16     along with this program; if not, see <http://www.gnu.org/licenses/>.
  17
  18     */
  19
  20
  21 #ifndef _EVENTS_C_
  22 #define _EVENTS_C_
  23
  24 #include "basics.h"
  25 #include "events.h"
  26
  27 #include <signal.h>
  28 #include <stdlib.h>
  29
  30 #if !defined (SIM_EVENTS_POLL_RATE)
  31 #define SIM_EVENTS_POLL_RATE 0x1000
  32 #endif
  33
  34
  35
  36 /* The event queue maintains a single absolute time using two
  37    variables.
  38
  39    TIME_OF_EVENT: this holds the time at which the next event is ment
  40    to occure.  If no next event it will hold the time of the last
  41    event.
  42
  43    TIME_FROM_EVENT: The current distance from TIME_OF_EVENT.  If an
  44    event is pending, this will be positive.  If no future event is
  45    pending this will be negative.  This variable is decremented once
  46    for each iteration of a clock cycle.
  47
  48    Initially, the clock is started at time one (1) with TIME_OF_EVENT
  49    == 0 and TIME_FROM_EVENT == -1.
  50
  51    Clearly there is a bug in that this code assumes that the absolute
  52    time counter will never become greater than 2^62. */
  53
  54 typedef struct _event_entry event_entry;
  55 struct _event_entry {
  56   void *data;
  57   event_handler *handler;
  58   int64_t time_of_event;
  59   event_entry *next;
  60 };
  61
  62 struct _event_queue {
  63   int processing;
  64   event_entry *queue;
  65   event_entry *volatile held;
  66   event_entry *volatile *volatile held_end;
  67   int64_t time_of_event;
  68   int64_t time_from_event;
  69 };
  70
  71
  72 STATIC_INLINE_EVENTS\
  73 (void)
  74 sim_events_poll (void *data)
  75 {
  76   event_queue *queue = data;
  77   /* just re-schedule in 1000 million ticks time */
  78   event_queue_schedule (queue, SIM_EVENTS_POLL_RATE, sim_events_poll, queue);
  79   sim_io_poll_quit ();
  80 }
  81
  82
  83 INLINE_EVENTS\
  84 (event_queue *)
  85 event_queue_create(void)
  86 {
  87   event_queue *new_event_queue = ZALLOC(event_queue);
  88
  89   new_event_queue->processing = 0;
  90   new_event_queue->queue = NULL;
  91   new_event_queue->held = NULL;
  92   new_event_queue->held_end = &new_event_queue->held;
  93
  94   /* both times are already zero */
  95   return new_event_queue;
  96 }
  97
  98
  99 INLINE_EVENTS\
 100 (void)
 101 event_queue_init(event_queue *queue)
 102 {
 103   event_entry *event;
 104
 105   /* drain the interrupt queue */
 106   {
 107 #if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
 108     sigset_t old_mask;
 109     sigset_t new_mask;
 110     sigfillset(&new_mask);
 111     /*-LOCK-*/ sigprocmask(SIG_SETMASK, &new_mask, &old_mask);
 112 #endif
 113     event = queue->held;
 114     while (event != NULL) {
 115       event_entry *dead = event;
 116       event = event->next;
 117       free(dead);
 118     }
 119     queue->held = NULL;
 120     queue->held_end = &queue->held;
 121 #if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
 122     /*-UNLOCK-*/ sigprocmask(SIG_SETMASK, &old_mask, NULL);
 123 #endif
 124   }
 125
 126   /* drain the normal queue */
 127   event = queue->queue;
 128   while (event != NULL) {
 129     event_entry *dead = event;
 130     event = event->next;
 131     free(dead);
 132   }
 133   queue->queue = NULL;
 134
 135   /* wind time back to one */
 136   queue->processing = 0;
 137   queue->time_of_event = 0;
 138   queue->time_from_event = -1;
 139
 140   /* schedule our initial counter event */
 141   event_queue_schedule (queue, 0, sim_events_poll, queue);
 142 }
 143
 144 INLINE_EVENTS\
 145 (int64_t)
 146 event_queue_time(event_queue *queue)
 147 {
 148   return queue->time_of_event - queue->time_from_event;
 149 }
 150
 151 STATIC_INLINE_EVENTS\
 152 (void)
 153 update_time_from_event(event_queue *events)
 154 {
 155   int64_t current_time = event_queue_time(events);
 156   if (events->queue != NULL) {
 157     events->time_from_event = (events->queue->time_of_event - current_time);
 158     events->time_of_event = events->queue->time_of_event;
 159   }
 160   else {
 161     events->time_of_event = current_time - 1;
 162     events->time_from_event = -1;
 163   }
 164   if (WITH_TRACE && ppc_trace[trace_events])
 165     {
 166       event_entry *event;
 167       int i;
 168       for (event = events->queue, i = 0;
 169            event != NULL;
 170            event = event->next, i++)
 171         {
 172           TRACE(trace_events, ("event time-from-event - time %" PRIi64 ", delta %" PRIi64 " - event %d, tag %p, time %" PRIi64 ", handler %p, data %p\n",
 173                                current_time,
 174                                events->time_from_event,
 175                                i,
 176                                event,
 177                                event->time_of_event,
 178                                event->handler,
 179                                event->data));
 180         }
 181     }
 182   ASSERT(current_time == event_queue_time(events));
 183 }
 184
 185 STATIC_INLINE_EVENTS\
 186 (void)
 187 insert_event_entry(event_queue *events,
 188                    event_entry *new_event,
 189                    int64_t delta)
 190 {
 191   event_entry *curr;
 192   event_entry **prev;
 193   int64_t time_of_event;
 194
 195   if (delta < 0)
 196     error("what is past is past!\n");
 197
 198   /* compute when the event should occure */
 199   time_of_event = event_queue_time(events) + delta;
 200
 201   /* find the queue insertion point - things are time ordered */
 202   prev = &events->queue;
 203   curr = events->queue;
 204   while (curr != NULL && time_of_event >= curr->time_of_event) {
 205     ASSERT(curr->next == NULL
 206            || curr->time_of_event <= curr->next->time_of_event);
 207     prev = &curr->next;
 208     curr = curr->next;
 209   }
 210   ASSERT(curr == NULL || time_of_event < curr->time_of_event);
 211
 212   /* insert it */
 213   new_event->next = curr;
 214   *prev = new_event;
 215   new_event->time_of_event = time_of_event;
 216
 217   /* adjust the time until the first event */
 218   update_time_from_event(events);
 219 }
 220
 221 INLINE_EVENTS\
 222 (event_entry_tag)
 223 event_queue_schedule(event_queue *events,
 224                      int64_t delta_time,
 225                      event_handler *handler,
 226                      void *data)
 227 {
 228   event_entry *new_event = ZALLOC(event_entry);
 229   new_event->data = data;
 230   new_event->handler = handler;
 231   insert_event_entry(events, new_event, delta_time);
 232   TRACE(trace_events, ("event scheduled at %" PRIi64 " - tag %p - time %" PRIi64 ", handler %p, data %p\n",
 233                        event_queue_time(events),
 234                        new_event,
 235                        new_event->time_of_event,
 236                        new_event->handler,
 237                        new_event->data));
 238   return (event_entry_tag)new_event;
 239 }
 240
 241
 242 INLINE_EVENTS\
 243 (event_entry_tag)
 244 event_queue_schedule_after_signal(event_queue *events,
 245                                   int64_t delta_time,
 246                                   event_handler *handler,
 247                                   void *data)
 248 {
 249   event_entry *new_event = ZALLOC(event_entry);
 250
 251   new_event->data = data;
 252   new_event->handler = handler;
 253   new_event->time_of_event = delta_time; /* work it out later */
 254   new_event->next = NULL;
 255
 256   {
 257 #if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
 258     sigset_t old_mask;
 259     sigset_t new_mask;
 260     sigfillset(&new_mask);
 261     /*-LOCK-*/ sigprocmask(SIG_SETMASK, &new_mask, &old_mask);
 262 #endif
 263     if (events->held == NULL) {
 264       events->held = new_event;
 265     }
 266     else {
 267       *events->held_end = new_event;
 268     }
 269     events->held_end = &new_event->next;
 270 #if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
 271     /*-UNLOCK-*/ sigprocmask(SIG_SETMASK, &old_mask, NULL);
 272 #endif
 273   }
 274
 275   TRACE(trace_events, ("event scheduled at %" PRIi64 " - tag %p - time %" PRIi64 ", handler %p, data %p\n",
 276                        event_queue_time(events),
 277                        new_event,
 278                        new_event->time_of_event,
 279                        new_event->handler,
 280                        new_event->data));
 281
 282   return (event_entry_tag)new_event;
 283 }
 284
 285
 286 INLINE_EVENTS\
 287 (void)
 288 event_queue_deschedule(event_queue *events,
 289                        event_entry_tag event_to_remove)
 290 {
 291   event_entry *to_remove = (event_entry*)event_to_remove;
 292   ASSERT((events->time_from_event >= 0) == (events->queue != NULL));
 293   if (event_to_remove != NULL) {
 294     event_entry *current;
 295     event_entry **ptr_to_current;
 296     for (ptr_to_current = &events->queue, current = *ptr_to_current;
 297          current != NULL && current != to_remove;
 298          ptr_to_current = &current->next, current = *ptr_to_current);
 299     if (current == to_remove) {
 300       *ptr_to_current = current->next;
 301       TRACE(trace_events, ("event descheduled at %" PRIi64 " - tag %p - time %" PRIi64 ", handler %p, data %p\n",
 302                            event_queue_time(events),
 303                            event_to_remove,
 304                            current->time_of_event,
 305                            current->handler,
 306                            current->data));
 307       free(current);
 308       update_time_from_event(events);
 309     }
 310     else {
 311       TRACE(trace_events, ("event descheduled at %" PRIi64 " - tag %p - not found\n",
 312                            event_queue_time(events),
 313                            event_to_remove));
 314     }
 315   }
 316   ASSERT((events->time_from_event >= 0) == (events->queue != NULL));
 317 }
 318
 319
 320
 321
 322 INLINE_EVENTS\
 323 (int)
 324 event_queue_tick(event_queue *events)
 325 {
 326   int64_t time_from_event;
 327
 328   /* we should only be here when the previous tick has been fully processed */
 329   ASSERT(!events->processing);
 330
 331   /* move any events that were queued by any signal handlers onto the
 332      real event queue.  BTW: When inlining, having this code here,
 333      instead of in event_queue_process() causes GCC to put greater
 334      weight on keeping the pointer EVENTS in a register.  This, in
 335      turn results in better code being output. */
 336   if (events->held != NULL) {
 337     event_entry *held_events;
 338     event_entry *curr_event;
 339
 340     {
 341 #if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
 342       sigset_t old_mask;
 343       sigset_t new_mask;
 344       sigfillset(&new_mask);
 345       /*-LOCK-*/ sigprocmask(SIG_SETMASK, &new_mask, &old_mask);
 346 #endif
 347       held_events = events->held;
 348       events->held = NULL;
 349       events->held_end = &events->held;
 350 #if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
 351       /*-UNLOCK-*/ sigprocmask(SIG_SETMASK, &old_mask, NULL);
 352 #endif
 353     }
 354
 355     do {
 356       curr_event = held_events;
 357       held_events = curr_event->next;
 358       insert_event_entry(events, curr_event, curr_event->time_of_event);
 359     } while (held_events != NULL);
 360   }
 361
 362   /* advance time, checking to see if we've reached time zero which
 363      would indicate the time for the next event has arrived */
 364   time_from_event = events->time_from_event;
 365   events->time_from_event = time_from_event - 1;
 366   return time_from_event == 0;
 367 }
 368
 369
 370
 371 INLINE_EVENTS\
 372 (void)
 373 event_queue_process(event_queue *events)
 374 {
 375   int64_t event_time = event_queue_time(events);
 376
 377   ASSERT((events->time_from_event == -1 && events->queue != NULL)
 378          || events->processing); /* something to do */
 379
 380   /* consume all events for this or earlier times.  Be careful to
 381      allow a new event to appear under our feet */
 382   events->processing = 1;
 383   while (events->queue != NULL
 384          && events->queue->time_of_event <= event_time) {
 385     event_entry *to_do = events->queue;
 386     event_handler *handler = to_do->handler;
 387     void *data = to_do->data;
 388     events->queue = to_do->next;
 389     TRACE(trace_events, ("event issued at %" PRIi64 " - tag %p - time %" PRIi64 ", handler %p, data %p\n",
 390                          event_time,
 391                          to_do,
 392                          to_do->time_of_event,
 393                          handler,
 394                          data));
 395     free(to_do);
 396     /* Always re-compute the time to the next event so that HANDLER()
 397        can safely insert new events into the queue. */
 398     update_time_from_event(events);
 399     handler(data);
 400   }
 401   events->processing = 0;
 402
 403   ASSERT(events->time_from_event > 0);
 404   ASSERT(events->queue != NULL); /* always poll event */
 405 }
 406
 407
 408 #endif /* _EVENTS_C_ */