/*****************************************************************************  The following code is derived, directly or indirectly, from the SystemC  source code Copyright (c) 1996-2002 by all Contributors.  All Rights reserved.  The contents of this file are subject to the restrictions and limitations  set forth in the SystemC Open Source License Version 2.3 (the "License");  You may not use this file except in compliance with such restrictions and  limitations. You may obtain instructions on how to receive a copy of the  License at http://www.systemc.org/. Software distributed by Contributors  under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF  ANY KIND, either express or implied. See the License for the specific  language governing rights and limitations under the License. *****************************************************************************//*****************************************************************************   simple_bus_arbiter.cpp : The arbitration unit.   Original Author: Ric Hilderink, Synopsys, Inc., 2001-10-11  *****************************************************************************/ /*****************************************************************************   MODIFICATION LOG - modifiers, enter your name, affiliation, date and  changes you are making here.       Name, Affiliation, Date:  Description of Modification:  *****************************************************************************/#include "simple_bus_arbiter.h"simple_bus_request *simple_bus_arbiter::arbitrate(const simple_bus_request_vec &requests){  int i;  // at least one request is here  simple_bus_request *best_request = requests[0];   if (m_verbose)     { // shows the list of pending requests      sb_fprintf(stdout, "%g %s :", sc_simulation_time(), name());      for (i = 0; i < requests.size(); ++i)	{	  simple_bus_request *request = requests[i];          // simple_bus_lock_status encoding          const char lock_chars[] = { '-', '=', '+' };          // simple_bus_status encoding           sb_fprintf(stdout, "\n    R[%d](%c%s@%x)",                     request->priority,                     lock_chars[request->lock],                     simple_bus_status_str[request->status],                     request->address);	}    }  // highest priority: status==SIMPLE_BUS_WAIT and lock is set:   // locked burst-action  for (i = 0; i < requests.size(); ++i)    {      simple_bus_request *request = requests[i];      if ((request->status == SIMPLE_BUS_WAIT) &&	  (request->lock == SIMPLE_BUS_LOCK_SET))	{	  // cannot break-in a locked burst	  if (m_verbose)            sb_fprintf(stdout, " -> R[%d] (rule 1)\n", request->priority);	  return request;	}    }  // second priority: lock is set at previous call,   // i.e. SIMPLE_BUS_LOCK_GRANTED  for (i = 0; i < requests.size(); ++i)    if (requests[i]->lock == SIMPLE_BUS_LOCK_GRANTED)      {	if (m_verbose)	  sb_fprintf(stdout, " -> R[%d] (rule 2)\n", requests[i]->priority);	return requests[i];      }  // third priority: priority  for (i = 1; i < requests.size(); ++i)    {      sc_assert(requests[i]->priority != best_request->priority);      if (requests[i]->priority < best_request->priority)	best_request = requests[i];    }  if (best_request->lock != SIMPLE_BUS_LOCK_NO)    best_request->lock = SIMPLE_BUS_LOCK_GRANTED;	  if (m_verbose)     sb_fprintf(stdout, " -> R[%d] (rule 3)\n", best_request->priority);  return best_request;}