PerfectCacheMemory.hh revision 11020:882ce080c9f7 
1/*
2 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
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
29#ifndef __MEM_RUBY_STRUCTURES_PERFECTCACHEMEMORY_HH__
30#define __MEM_RUBY_STRUCTURES_PERFECTCACHEMEMORY_HH__
31
32#include "base/hashmap.hh"
33#include "mem/protocol/AccessPermission.hh"
34#include "mem/ruby/common/Address.hh"
35
36template<class ENTRY>
37struct PerfectCacheLineState
38{
39    PerfectCacheLineState() { m_permission = AccessPermission_NUM; }
40    AccessPermission m_permission;
41    ENTRY m_entry;
42};
43
44template<class ENTRY>
45inline std::ostream&
46operator<<(std::ostream& out, const PerfectCacheLineState<ENTRY>& obj)
47{
48    return out;
49}
50
51template<class ENTRY>
52class PerfectCacheMemory
53{
54  public:
55    PerfectCacheMemory();
56
57    // tests to see if an address is present in the cache
58    bool isTagPresent(const Address& address) const;
59
60    // Returns true if there is:
61    //   a) a tag match on this address or there is
62    //   b) an Invalid line in the same cache "way"
63    bool cacheAvail(const Address& address) const;
64
65    // find an Invalid entry and sets the tag appropriate for the address
66    void allocate(const Address& address);
67
68    void deallocate(const Address& address);
69
70    // Returns with the physical address of the conflicting cache line
71    Address cacheProbe(const Address& newAddress) const;
72
73    // looks an address up in the cache
74    ENTRY* lookup(const Address& address);
75    const ENTRY* lookup(const Address& address) const;
76
77    // Get/Set permission of cache block
78    AccessPermission getPermission(const Address& address) const;
79    void changePermission(const Address& address, AccessPermission new_perm);
80
81    // Print cache contents
82    void print(std::ostream& out) const;
83
84  private:
85    // Private copy constructor and assignment operator
86    PerfectCacheMemory(const PerfectCacheMemory& obj);
87    PerfectCacheMemory& operator=(const PerfectCacheMemory& obj);
88
89    // Data Members (m_prefix)
90    m5::hash_map<Address, PerfectCacheLineState<ENTRY> > m_map;
91};
92
93template<class ENTRY>
94inline std::ostream&
95operator<<(std::ostream& out, const PerfectCacheMemory<ENTRY>& obj)
96{
97    obj.print(out);
98    out << std::flush;
99    return out;
100}
101
102template<class ENTRY>
103inline
104PerfectCacheMemory<ENTRY>::PerfectCacheMemory()
105{
106}
107
108// tests to see if an address is present in the cache
109template<class ENTRY>
110inline bool
111PerfectCacheMemory<ENTRY>::isTagPresent(const Address& address) const
112{
113    return m_map.count(line_address(address)) > 0;
114}
115
116template<class ENTRY>
117inline bool
118PerfectCacheMemory<ENTRY>::cacheAvail(const Address& address) const
119{
120    return true;
121}
122
123// find an Invalid or already allocated entry and sets the tag
124// appropriate for the address
125template<class ENTRY>
126inline void
127PerfectCacheMemory<ENTRY>::allocate(const Address& address)
128{
129    PerfectCacheLineState<ENTRY> line_state;
130    line_state.m_permission = AccessPermission_Invalid;
131    line_state.m_entry = ENTRY();
132    m_map[line_address(address)] = line_state;
133}
134
135// deallocate entry
136template<class ENTRY>
137inline void
138PerfectCacheMemory<ENTRY>::deallocate(const Address& address)
139{
140    m_map.erase(line_address(address));
141}
142
143// Returns with the physical address of the conflicting cache line
144template<class ENTRY>
145inline Address
146PerfectCacheMemory<ENTRY>::cacheProbe(const Address& newAddress) const
147{
148    panic("cacheProbe called in perfect cache");
149    return newAddress;
150}
151
152// looks an address up in the cache
153template<class ENTRY>
154inline ENTRY*
155PerfectCacheMemory<ENTRY>::lookup(const Address& address)
156{
157    return &m_map[line_address(address)].m_entry;
158}
159
160// looks an address up in the cache
161template<class ENTRY>
162inline const ENTRY*
163PerfectCacheMemory<ENTRY>::lookup(const Address& address) const
164{
165    return &m_map[line_address(address)].m_entry;
166}
167
168template<class ENTRY>
169inline AccessPermission
170PerfectCacheMemory<ENTRY>::getPermission(const Address& address) const
171{
172    return m_map[line_address(address)].m_permission;
173}
174
175template<class ENTRY>
176inline void
177PerfectCacheMemory<ENTRY>::changePermission(const Address& address,
178                                            AccessPermission new_perm)
179{
180    Address line_address = address;
181    line_address.makeLineAddress();
182    PerfectCacheLineState<ENTRY>& line_state = m_map[line_address];
183    line_state.m_permission = new_perm;
184}
185
186template<class ENTRY>
187inline void
188PerfectCacheMemory<ENTRY>::print(std::ostream& out) const
189{
190}
191
192#endif // __MEM_RUBY_STRUCTURES_PERFECTCACHEMEMORY_HH__
193