1/*
2 * Copyright (c) 2019 Inria
3 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Daniel Carvalho
30 */
31
32#include "base/filters/block_bloom_filter.hh"
33
34#include "base/bitfield.hh"
35#include "base/logging.hh"
36#include "params/BloomFilterBlock.hh"
37
38namespace BloomFilter {
39
40Block::Block(const BloomFilterBlockParams* p)
41    : Base(p), masksLSBs(p->masks_lsbs),
42      masksSizes(p->masks_sizes)
43{
44    fatal_if(masksLSBs.size() != masksSizes.size(),
45        "Masks haven't been properly provided");
46    fatal_if(masksLSBs.size() < 1,
47        "There must be at least one mask to extract an address bitfield");
48
49    for (int i = 0; i < masksLSBs.size(); i++) {
50        fatal_if((masksSizes[i] > sizeBits) || (masksSizes[i] <= 0),
51            "The bitfields must be indexable in the filter");
52        fatal_if(masksLSBs[i] + masksSizes[i] >
53            std::numeric_limits<Addr>::digits,
54            "The total size of the bitfields cannot be bigger than the " \
55            "number of bits in an address");
56    }
57}
58
59Block::~Block()
60{
61}
62
63void
64Block::set(Addr addr)
65{
66    filter[hash(addr)]++;
67}
68
69void
70Block::unset(Addr addr)
71{
72    filter[hash(addr)]--;
73}
74
75int
76Block::getCount(Addr addr) const
77{
78    return filter[hash(addr)];
79}
80
81int
82Block::hash(Addr addr) const
83{
84    Addr hashed_addr = 0;
85    for (int i = 0; i < masksLSBs.size(); i++) {
86        hashed_addr ^=
87            bits(addr, offsetBits + masksLSBs[i] + masksSizes[i] - 1,
88            offsetBits + masksLSBs[i]);
89    }
90    assert(hashed_addr < filter.size());
91    return hashed_addr;
92}
93
94} // namespace BloomFilter
95
96BloomFilter::Block*
97BloomFilterBlockParams::create()
98{
99    return new BloomFilter::Block(this);
100}
101
102