Add PowerPC simulator from Andrew Cagney <cagney@highland.com.au>

1 files changed, 238 insertions, 0 deletions

diff --git a/sim/ppc/events.c b/sim/ppc/events.c
new file mode 100644
index 0000000..4b26a6a
--- /dev/null
+++ b/sim/ppc/events.c
@@ -0,0 +1,238 @@
+/*  This file is part of the program psim.
+
+    Copyright (C) 1994-1995, Andrew Cagney <cagney@highland.com.au>
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+ 
+    You should have received a copy of the GNU General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ 
+    */
+
+
+#ifndef _EVENTS_C_
+#define _EVENTS_C_
+
+#ifndef STATIC_INLINE_EVENTS
+#define STATIC_INLINE_EVENTS STATIC_INLINE
+#endif
+
+
+#include "basics.h"
+#include "events.h"
+
+
+/* The event queue maintains a single absolute time using two
+   variables.
+   
+   TIME_OF_EVENT: this holds the time at which the next event is ment
+   to occure.  If no next event it will hold the time of the last
+   event.  The first event occures at time 0 - system start.
+
+   TIME_FROM_EVENT: The current distance from TIME_OF_EVENT.  If an
+   event is pending, this will be positive.  If no future event is
+   pending this will be negative.  This variable is decremented once
+   for each iteration of a clock cycle.
+
+   Clearly there is a bug in that this code assumes that the absolute
+   time counter will never become greater than 2^62. */
+
+typedef struct _event_entry event_entry;
+struct _event_entry {
+  void *data;
+  event_handler *handler;
+  signed64 time_of_event;  
+  event_entry *next;
+};
+
+struct _event_queue {
+  event_entry *queue;
+  event_entry *volatile held;
+  event_entry *volatile *volatile held_end;
+  signed64 time_of_event;
+  signed64 time_from_event;
+};
+
+
+INLINE_EVENTS event_queue *
+event_queue_create(void)
+{
+  event_queue *new_event_queue = ZALLOC(event_queue);
+
+  new_event_queue->queue = NULL;
+  new_event_queue->held = NULL;
+  new_event_queue->held_end = &new_event_queue->held;
+  /* both times are already zero */
+  return new_event_queue;
+}
+
+
+
+STATIC_INLINE_EVENTS void
+insert_event_entry(event_queue *events,
+		   event_entry *new_event,
+		   signed64 delta)
+{
+  event_entry *curr;
+  event_entry **last;
+  signed64 time_of_event;
+
+  if (delta <= 0)
+    error("can not schedule event for current time\n");
+
+  /* compute when the event should occure */
+  time_of_event = (events->time_of_event
+		   - events->time_from_event
+		   + delta);
+
+  /* find the queue insertion point - things are time ordered */
+  last = &events->queue;
+  curr = events->queue;
+  while (curr != NULL && time_of_event >= curr->time_of_event) {
+    last = &curr->next;
+    curr = curr->next;
+  }
+
+  /* insert it */
+  new_event->next = curr;
+  *last = new_event;
+  new_event->time_of_event = time_of_event;
+
+  /* adjust the time until the first event */
+  events->time_from_event = (events->queue->time_of_event
+			     - (events->time_of_event
+				- events->time_from_event));
+  events->time_of_event = events->queue->time_of_event;
+}
+
+INLINE_EVENTS event_entry_tag
+event_queue_schedule(event_queue *events,
+		     signed64 delta_time,
+		     event_handler *handler,
+		     void *data)
+{
+  event_entry *new_event = ZALLOC(event_entry);
+  new_event->data = data;
+  new_event->handler = handler;
+  insert_event_entry(events, new_event, delta_time);
+  return new_event;
+}
+
+
+INLINE_EVENTS event_entry_tag
+event_queue_schedule_after_signal(event_queue *events,
+				  signed64 delta_time,
+				  event_handler *handler,
+				  void *data)
+{
+  event_entry *new_event = ZALLOC(event_entry);
+
+  new_event->data = data;
+  new_event->handler = handler;
+  new_event->time_of_event = delta_time; /* work it out later */
+  new_event->next = NULL;
+
+  /*-LOCK-*/
+  if (events->held == NULL) {
+    events->held = new_event;
+  }
+  else {
+    *events->held_end = new_event;
+  }
+  events->held_end = &new_event->next;
+  /*-UNLOCK-*/
+
+  return new_event;
+}
+
+
+INLINE_EVENTS void
+event_queue_deschedule(event_queue *events,
+		       event_entry_tag event_to_remove)
+{
+  if (event_to_remove != NULL) {
+    event_entry *current;
+    event_entry **ptr_to_current;
+    for (ptr_to_current = &events->queue, current = *ptr_to_current;
+	 current != NULL && current != event_to_remove;
+	 ptr_to_current = &current->next, current = *ptr_to_current);
+    if (current == event_to_remove) {
+      *ptr_to_current = current->next;
+      zfree(current);
+      /* Just forget to recompute the delay to the next event */
+    }
+  }
+}
+
+
+
+
+INLINE_EVENTS int
+event_queue_tick(event_queue *events)
+{
+  /* remove things from the asynchronous event queue onto the real one */
+  if (events->held != NULL) {
+    event_entry *held_events;
+    event_entry *curr_event;
+
+    /*-LOCK-*/
+    held_events = events->held;
+    events->held = NULL;
+    events->held_end = &events->held;
+    /*-UNLOCK-*/
+
+    do {
+      curr_event = held_events;
+      held_events = curr_event->next;
+      insert_event_entry(events, curr_event, curr_event->time_of_event);
+    } while (held_events != NULL);
+  }
+
+  /* advance time, checking to see if we've reached time zero which
+     would indicate the time for the next event has arrived */
+  events->time_from_event -= 1;
+  return events->time_from_event == 0;
+}
+
+INLINE_EVENTS void
+event_queue_process(event_queue *events)
+{
+  if (events->time_from_event == 0) {
+    /* consume all events for this or earlier times */
+    do {
+      event_entry *to_do = events->queue;
+      events->queue = to_do->next;
+      to_do->handler(events,
+		     to_do->data);
+      zfree(to_do);
+    } while (events->queue != NULL
+	     && events->queue->time_of_event <= events->time_of_event);
+    /* re-caculate time for new events */
+    if (events->queue != NULL) {
+      events->time_from_event = (events->queue->time_of_event
+				 - events->time_of_event);
+      events->time_of_event = events->queue->time_of_event;
+    }
+    else {
+      /* nothing to do, time_from_event will go negative */
+    }
+  }
+}
+
+INLINE_EVENTS signed64
+event_queue_time(event_queue *queue)
+{
+  return queue->time_of_event - queue->time_from_event;
+}
+
+
+#endif /* _EVENTS_C_ */