evtqueue.c

C++ 编写的EROS RTOS

/*
 * Copyright (C) 1998, 1999, Jonathan S. Shapiro.
 *
 * This file is part of the EROS Operating System.
 *
 * 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,
 * 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, 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

/* Event Queue -- impedence matcher for event passing. */

#include <eros/target.h>
#include <eros/Invoke.h>
#include <eros/ReturnerKey.h>
#include <eros/ProcessKey.h>
#include <eros/NodeKey.h>
#include <memory.h>
#include <domain/domdbg.h>
#include <domain/EventQueueKey.h>
#include <domain/ProtoSpace.h>

#include "constituents.h"

#define KR_DOMCRE      3
#define KR_SCHED       5

#define KR_CLIENT      6

#if EROS_NODE_SIZE != 32
#error "wrong node size!"
#endif

#define KR_OSTREAM     28
#define KR_RETURNER    29
#define KR_SCRATCH     30
#define KR_RESUME      31

#define KI_MASTER      128	/* key info of master start key */

#define NEVENT         64

typedef struct evt_s {
  uint32_t	w0;
  uint32_t	w1;
  uint32_t	w2;
} evt_s;


evt_s events[NEVENT];
int firstEvent = 0;
int nextEvent = 0;
int count = 0;			/* number of events in list */
int waiting = 0;		/* client is waiting */

uint32_t
PostEvent(Message *msg)
{
  if (count == NEVENT)
    return RC_EvtQ_Full;

  events[nextEvent].w0 = msg->rcv_w1;
  events[nextEvent].w1 = msg->rcv_w2;
  events[nextEvent].w2 = msg->rcv_w3;

  nextEvent++;
  
  if (nextEvent == NEVENT)
    nextEvent = 0;

  count++;

  if (waiting) {
    Message wakemsg;
    bzero(&wakemsg, sizeof(wakemsg));
    
    /*    kprintf(KR_OSTREAM, "Waking sleeper\n"); */
    
    wakemsg.snd_invKey = KR_CLIENT;
    wakemsg.snd_code = RC_OK;
    wakemsg.snd_w1 = events[firstEvent].w0;
    wakemsg.snd_w2 = events[firstEvent].w1;
    wakemsg.snd_w3 = events[firstEvent].w2;

    SEND(&wakemsg);

    kprintf(KR_OSTREAM, "Now awake\n");

    waiting = 0;
    
    if (firstEvent == NEVENT)
      firstEvent = 0;
    else
      firstEvent++;
    count--;
  }

  return RC_OK;
}

uint32_t
PollEvent(Message *msg, int shouldWait)
{
  /* Special case if evt Q is full to pull the first item.  Otherwise
     we can use the simple logic. */
  if (count == 0) {
    if (shouldWait) {
      msg->snd_invKey = KR_VOID;
      waiting = 1;
    }

    return RC_EvtQ_Empty;
  }
  
  msg->snd_w1 = events[firstEvent].w0;
  msg->snd_w2 = events[firstEvent].w1;
  msg->snd_w3 = events[firstEvent].w2;

  firstEvent++;
  
  if (firstEvent == NEVENT)
    firstEvent = 0;

  count--;
  
  return RC_OK;
}

volatile void
teardown()
{
  /* get the protospace */
  node_copy(KR_CONSTIT, KC_PROTOSPC, KR_SCRATCH);

  /* destroy as small space. */
  protospace_destroy(KR_RETURNER, KR_SCRATCH, KR_SELF, KR_DOMCRE,
		     KR_BANK, 1);
  /* NOTREACHED */
}

int
ProcessRequest(Message *msg)
{
  uint32_t result = RC_OK;
  uint32_t code = msg->rcv_code;
  
  msg->snd_w1 = 0;
  msg->snd_key0 = KR_VOID;

  switch(code) {
  case OC_EvtQ_Post:
    result = PostEvent(msg);
    break;
    
  case OC_EvtQ_Poll:
    result = PollEvent(msg, 0);
    break;
    
  case OC_EvtQ_Wait:
    result = PollEvent(msg, 1);
    break;

  case OC_Destroy:
    teardown();
    break;
    
  default:
    result = RC_UnknownRequest;
    break;
  }

  msg->snd_code = result;
  msg->rcv_key3 = waiting ? KR_RESUME : KR_CLIENT;

  return 1;
}

int
main(void)
{
  uint32_t result;
  Message msg;
  
  msg.snd_invKey = KR_VOID;
  msg.snd_key0 = KR_VOID;
  msg.snd_key1 = KR_VOID;
  msg.snd_key2 = KR_VOID;
  msg.snd_key3 = KR_VOID;
  msg.snd_data = 0;
  msg.snd_len = 0;
  msg.snd_code = 0;
  msg.snd_w1 = 0;
  msg.snd_w2 = 0;
  msg.snd_w3 = 0;

  msg.rcv_key0 = KR_VOID;
  msg.rcv_key1 = KR_VOID;
  msg.rcv_key2 = KR_VOID;
  msg.rcv_key3 = KR_RESUME;
  msg.rcv_len = 0;
  msg.rcv_data = 0;
  msg.rcv_code = 0;
  msg.rcv_w1 = 0;
  msg.rcv_w2 = 0;
  msg.rcv_w3 = 0;

  node_copy(KR_CONSTIT, KC_RETURNER, KR_RETURNER);
  node_copy(KR_CONSTIT, KC_OSTREAM, KR_OSTREAM);

  /* Fabricate the master start key and arrange to return that: */
  result = process_make_start_key(KR_SELF, 0, KR_SCRATCH);
  if (result != RC_OK)
    kdprintf(KR_OSTREAM, "Result from evtq cre strt key: 0x%x\n",
	     result);
  
  msg.snd_key0 = KR_SCRATCH;
#ifdef USE_RETURNER
  msg.snd_invKey = KR_RETURNER;
  msg.snd_key3 = KR_RESUME;
#else    
  msg.snd_invKey = KR_RESUME;
#endif

  msg.rcv_key3 = KR_CLIENT;

  RETURN(&msg);

  msg.snd_key0 = KR_VOID;
  
  for(;;) {
    msg.snd_invKey = msg.rcv_key3;
    
    (void) ProcessRequest(&msg);

    RETURN(&msg);
  }
}