events.c
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/* This file is part of the program psim.
Copyright (C) 1994-1998, 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_
#include "basics.h"
#include "events.h"
#include <signal.h>
#if !defined (SIM_EVENTS_POLL_RATE)
#define SIM_EVENTS_POLL_RATE 0x1000
#endif
/* 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.
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.
Initially, the clock is started at time one (1) with TIME_OF_EVENT
== 0 and TIME_FROM_EVENT == -1.
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 {
int processing;
event_entry *queue;
event_entry *volatile held;
event_entry *volatile *volatile held_end;
signed64 time_of_event;
signed64 time_from_event;
};
STATIC_INLINE_EVENTS\
(void)
sim_events_poll (void *data)
{
event_queue *queue = data;
/* just re-schedule in 1000 million ticks time */
event_queue_schedule (queue, SIM_EVENTS_POLL_RATE, sim_events_poll, queue);
sim_io_poll_quit ();
}
INLINE_EVENTS\
(event_queue *)
event_queue_create(void)
{
event_queue *new_event_queue = ZALLOC(event_queue);
new_event_queue->processing = 0;
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;
}
INLINE_EVENTS\
(void)
event_queue_init(event_queue *queue)
{
event_entry *event;
/* drain the interrupt queue */
{
#if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
sigset_t old_mask;
sigset_t new_mask;
sigfillset(&new_mask);
/*-LOCK-*/ sigprocmask(SIG_SETMASK, &new_mask, &old_mask);
#endif
event = queue->held;
while (event != NULL) {
event_entry *dead = event;
event = event->next;
zfree(dead);
}
queue->held = NULL;
queue->held_end = &queue->held;
#if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
/*-UNLOCK-*/ sigprocmask(SIG_SETMASK, &old_mask, NULL);
#endif
}
/* drain the normal queue */
event = queue->queue;
while (event != NULL) {
event_entry *dead = event;
event = event->next;
zfree(dead);
}
queue->queue = NULL;
/* wind time back to one */
queue->processing = 0;
queue->time_of_event = 0;
queue->time_from_event = -1;
/* schedule our initial counter event */
event_queue_schedule (queue, 0, sim_events_poll, queue);
}
INLINE_EVENTS\
(signed64)
event_queue_time(event_queue *queue)
{
return queue->time_of_event - queue->time_from_event;
}
STATIC_INLINE_EVENTS\
(void)
update_time_from_event(event_queue *events)
{
signed64 current_time = event_queue_time(events);
if (events->queue != NULL) {
events->time_from_event = (events->queue->time_of_event - current_time);
events->time_of_event = events->queue->time_of_event;
}
else {
events->time_of_event = current_time - 1;
events->time_from_event = -1;
}
if (WITH_TRACE && ppc_trace[trace_events])
{
event_entry *event;
int i;
for (event = events->queue, i = 0;
event != NULL;
event = event->next, i++)
{
TRACE(trace_events, ("event time-from-event - time %ld, delta %ld - event %d, tag 0x%lx, time %ld, handler 0x%lx, data 0x%lx\n",
(long)current_time,
(long)events->time_from_event,
i,
(long)event,
(long)event->time_of_event,
(long)event->handler,
(long)event->data));
}
}
ASSERT(current_time == event_queue_time(events));
}
STATIC_INLINE_EVENTS\
(void)
insert_event_entry(event_queue *events,
event_entry *new_event,
signed64 delta)
{
event_entry *curr;
event_entry **prev;
signed64 time_of_event;
if (delta < 0)
error("what is past is past!\n");
/* compute when the event should occure */
time_of_event = event_queue_time(events) + delta;
/* find the queue insertion point - things are time ordered */
prev = &events->queue;
curr = events->queue;
while (curr != NULL && time_of_event >= curr->time_of_event) {
ASSERT(curr->next == NULL
|| curr->time_of_event <= curr->next->time_of_event);
prev = &curr->next;
curr = curr->next;
}
ASSERT(curr == NULL || time_of_event < curr->time_of_event);
/* insert it */
new_event->next = curr;
*prev = new_event;
new_event->time_of_event = time_of_event;
/* adjust the time until the first event */
update_time_from_event(events);
}
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);
TRACE(trace_events, ("event scheduled at %ld - tag 0x%lx - time %ld, handler 0x%lx, data 0x%lx\n",
(long)event_queue_time(events),
(long)new_event,
(long)new_event->time_of_event,
(long)new_event->handler,
(long)new_event->data));
return (event_entry_tag)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;
{
#if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
sigset_t old_mask;
sigset_t new_mask;
sigfillset(&new_mask);
/*-LOCK-*/ sigprocmask(SIG_SETMASK, &new_mask, &old_mask);
#endif
if (events->held == NULL) {
events->held = new_event;
}
else {
*events->held_end = new_event;
}
events->held_end = &new_event->next;
#if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
/*-UNLOCK-*/ sigprocmask(SIG_SETMASK, &old_mask, NULL);
#endif
}
TRACE(trace_events, ("event scheduled at %ld - tag 0x%lx - time %ld, handler 0x%lx, data 0x%lx\n",
(long)event_queue_time(events),
(long)new_event,
(long)new_event->time_of_event,
(long)new_event->handler,
(long)new_event->data));
return (event_entry_tag)new_event;
}
INLINE_EVENTS\
(void)
event_queue_deschedule(event_queue *events,
event_entry_tag event_to_remove)
{
event_entry *to_remove = (event_entry*)event_to_remove;
ASSERT((events->time_from_event >= 0) == (events->queue != NULL));
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 != to_remove;
ptr_to_current = ¤t->next, current = *ptr_to_current);
if (current == to_remove) {
*ptr_to_current = current->next;
TRACE(trace_events, ("event descheduled at %ld - tag 0x%lx - time %ld, handler 0x%lx, data 0x%lx\n",
(long)event_queue_time(events),
(long)event_to_remove,
(long)current->time_of_event,
(long)current->handler,
(long)current->data));
zfree(current);
update_time_from_event(events);
}
else {
TRACE(trace_events, ("event descheduled at %ld - tag 0x%lx - not found\n",
(long)event_queue_time(events),
(long)event_to_remove));
}
}
ASSERT((events->time_from_event >= 0) == (events->queue != NULL));
}
INLINE_EVENTS\
(int)
event_queue_tick(event_queue *events)
{
signed64 time_from_event;
/* we should only be here when the previous tick has been fully processed */
ASSERT(!events->processing);
/* move any events that were queued by any signal handlers onto the
real event queue. BTW: When inlining, having this code here,
instead of in event_queue_process() causes GCC to put greater
weight on keeping the pointer EVENTS in a register. This, in
turn results in better code being output. */
if (events->held != NULL) {
event_entry *held_events;
event_entry *curr_event;
{
#if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
sigset_t old_mask;
sigset_t new_mask;
sigfillset(&new_mask);
/*-LOCK-*/ sigprocmask(SIG_SETMASK, &new_mask, &old_mask);
#endif
held_events = events->held;
events->held = NULL;
events->held_end = &events->held;
#if defined(HAVE_SIGPROCMASK) && defined(SIG_SETMASK)
/*-UNLOCK-*/ sigprocmask(SIG_SETMASK, &old_mask, NULL);
#endif
}
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 */
time_from_event = events->time_from_event;
events->time_from_event = time_from_event - 1;
return time_from_event == 0;
}
INLINE_EVENTS\
(void)
event_queue_process(event_queue *events)
{
signed64 event_time = event_queue_time(events);
ASSERT((events->time_from_event == -1 && events->queue != NULL)
|| events->processing); /* something to do */
/* consume all events for this or earlier times. Be careful to
allow a new event to appear under our feet */
events->processing = 1;
while (events->queue != NULL
&& events->queue->time_of_event <= event_time) {
event_entry *to_do = events->queue;
event_handler *handler = to_do->handler;
void *data = to_do->data;
events->queue = to_do->next;
TRACE(trace_events, ("event issued at %ld - tag 0x%lx - time %ld, handler 0x%lx, data 0x%lx\n",
(long)event_time,
(long)to_do,
(long)to_do->time_of_event,
(long)handler,
(long)data));
zfree(to_do);
/* Always re-compute the time to the next event so that HANDLER()
can safely insert new events into the queue. */
update_time_from_event(events);
handler(data);
}
events->processing = 0;
ASSERT(events->time_from_event > 0);
ASSERT(events->queue != NULL); /* always poll event */
}
#endif /* _EVENTS_C_ */