WireBuffer.cc revision 10301:44839e8febbd 
1/*
2 * Copyright (c) 2010 Advanced Micro Devices, Inc.
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Author:  Lisa Hsu
29 *
30 */
31
32#include <algorithm>
33#include <functional>
34
35#include "base/cprintf.hh"
36#include "base/stl_helpers.hh"
37#include "mem/ruby/common/Global.hh"
38#include "mem/ruby/structures/WireBuffer.hh"
39#include "mem/ruby/system/System.hh"
40
41using namespace std;
42
43// Output operator definition
44
45ostream&
46operator<<(ostream& out, const WireBuffer& obj)
47{
48    obj.print(out);
49    out << flush;
50    return out;
51}
52
53
54// ****************************************************************
55
56// CONSTRUCTOR
57WireBuffer::WireBuffer(const Params *p)
58    : SimObject(p)
59{
60    m_msg_counter = 0;
61}
62
63void
64WireBuffer::init()
65{
66}
67
68WireBuffer::~WireBuffer()
69{
70}
71
72void
73WireBuffer::enqueue(MsgPtr message, Cycles latency)
74{
75    m_msg_counter++;
76    Cycles current_time = g_system_ptr->curCycle();
77    Cycles arrival_time = current_time + latency;
78    assert(arrival_time > current_time);
79
80    MessageBufferNode thisNode(arrival_time, m_msg_counter, message);
81    m_message_queue.push_back(thisNode);
82    if (m_consumer_ptr != NULL) {
83        m_consumer_ptr->
84            scheduleEventAbsolute(g_system_ptr->clockPeriod() * arrival_time);
85    } else {
86        panic("No Consumer for WireBuffer! %s\n", *this);
87    }
88}
89
90void
91WireBuffer::dequeue()
92{
93    assert(isReady());
94    pop_heap(m_message_queue.begin(), m_message_queue.end(),
95        greater<MessageBufferNode>());
96    m_message_queue.pop_back();
97}
98
99const Message*
100WireBuffer::peek()
101{
102    MessageBufferNode node = peekNode();
103    Message* msg_ptr = node.m_msgptr.get();
104    assert(msg_ptr != NULL);
105    return msg_ptr;
106}
107
108MessageBufferNode
109WireBuffer::peekNode()
110{
111    assert(isReady());
112    MessageBufferNode req = m_message_queue.front();
113    return req;
114}
115
116void
117WireBuffer::recycle()
118{
119    // Because you don't want anything reordered, make sure the recycle latency
120    // is just 1 cycle. As a result, you really want to use this only in
121    // Wire-like situations because you don't want to deadlock as a result of
122    // being stuck behind something if you're not actually supposed to.
123    assert(isReady());
124    MessageBufferNode node = m_message_queue.front();
125    pop_heap(m_message_queue.begin(), m_message_queue.end(),
126        greater<MessageBufferNode>());
127
128    node.m_time = g_system_ptr->curCycle() + Cycles(1);
129    m_message_queue.back() = node;
130    push_heap(m_message_queue.begin(), m_message_queue.end(),
131        greater<MessageBufferNode>());
132    m_consumer_ptr->
133        scheduleEventAbsolute(g_system_ptr->clockPeriod() * node.m_time);
134}
135
136bool
137WireBuffer::isReady()
138{
139    return ((!m_message_queue.empty()) &&
140            (m_message_queue.front().m_time <= g_system_ptr->curCycle()));
141}
142
143void
144WireBuffer::print(ostream& out) const
145{
146}
147
148void
149WireBuffer::wakeup()
150{
151}
152
153WireBuffer *
154RubyWireBufferParams::create()
155{
156    return new WireBuffer(this);
157}
158
159