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// $Id: arbiter.cpp 5188 2012-08-30 00:31:31Z dub $
/*
Copyright (c) 2007-2012, Trustees of The Leland Stanford Junior University
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this
list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
// ----------------------------------------------------------------------
//
// Arbiter: Base class for Matrix and Round Robin Arbiter
//
// ----------------------------------------------------------------------
#include "arbiter.hpp"
#include "roundrobin_arb.hpp"
#include "matrix_arb.hpp"
#include "tree_arb.hpp"
#include <limits>
#include <cassert>
using namespace std ;
Arbiter::Arbiter( Module *parent, const string &name, int size )
: Module( parent, name ),
_size(size), _selected(-1), _highest_pri(numeric_limits<int>::min()),
_best_input(-1), _num_reqs(0)
{
_request.resize(size);
for ( int i = 0 ; i < size ; i++ )
_request[i].valid = false ;
}
void Arbiter::AddRequest( int input, int id, int pri )
{
assert( 0 <= input && input < _size ) ;
assert( !_request[input].valid );
_num_reqs++ ;
_request[input].valid = true ;
_request[input].id = id ;
_request[input].pri = pri ;
}
int Arbiter::Arbitrate( int* id, int* pri )
{
if ( _selected != -1 ) {
if ( id )
*id = _request[_selected].id ;
if ( pri )
*pri = _request[_selected].pri ;
}
assert((_selected >= 0) || (_num_reqs == 0));
return _selected ;
}
void Arbiter::Clear()
{
if(_num_reqs > 0) {
// clear the request vector
for ( int i = 0; i < _size ; i++ )
_request[i].valid = false ;
_num_reqs = 0 ;
_selected = -1;
}
}
Arbiter *Arbiter::NewArbiter( Module *parent, const string& name,
const string &arb_type, int size)
{
Arbiter *a = NULL;
if(arb_type == "round_robin") {
a = new RoundRobinArbiter( parent, name, size );
} else if(arb_type == "matrix") {
a = new MatrixArbiter( parent, name, size );
} else if(arb_type.substr(0, 5) == "tree(") {
size_t left = 4;
size_t middle = arb_type.find_first_of(',');
assert(middle != string::npos);
size_t right = arb_type.find_last_of(')');
assert(right != string::npos);
string groups_str = arb_type.substr(left+1, middle-left-1);
int groups = atoi(groups_str.c_str());
string sub_arb_type = arb_type.substr(middle+1, right-middle-1);
a = new TreeArbiter( parent, name, size, groups, sub_arb_type );
} else assert(false);
return a;
}
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