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/*
* Copyright (c) 2019 Inria
* Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
* 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;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* 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.
*
* Authors: Daniel Carvalho
*/
#include "base/filters/bulk_bloom_filter.hh"
#include <vector>
#include <limits>
#include "base/bitfield.hh"
#include "params/BloomFilterBulk.hh"
namespace BloomFilter {
Bulk::Bulk(const BloomFilterBulkParams* p)
: Base(p), sectorBits(sizeBits - 1)
{
}
Bulk::~Bulk()
{
}
void
Bulk::set(Addr addr)
{
// c0 contains the cache index bits
int c0 = bits(addr, offsetBits + sectorBits - 1, offsetBits);
// c1 contains the lower sectorBits permuted bits
//Address permuted_bits = permute(addr);
int c1 = bits(addr, (offsetBits + 2 * sectorBits) - 1,
offsetBits + sectorBits);
//assert(c0 < (filter_size/2));
//assert(c0 + (filter_size/2) < filter_size);
//assert(c1 < (filter_size/2));
// set v0 bit
filter[c0 + (filter.size()/2)] = 1;
// set v1 bit
filter[c1] = 1;
}
bool
Bulk::isSet(Addr addr) const
{
// c0 contains the cache index bits
const int filter_size = filter.size();
int c0 = bits(addr, offsetBits + sectorBits - 1, offsetBits);
// c1 contains the lower 10 permuted bits
//Address permuted_bits = permute(addr);
int c1 = bits(addr, (offsetBits + 2 * sectorBits) - 1,
offsetBits + sectorBits);
//assert(c0 < (filter_size/2));
//assert(c0 + (filter_size/2) < filter_size);
//assert(c1 < (filter_size/2));
// set v0 bit
std::vector<int> temp_filter(filter.size(), 0);
temp_filter[c0 + (filter_size/2)] = 1;
// set v1 bit
temp_filter[c1] = 1;
// perform filter intersection. If any c part is 0, no possibility
// of address being in signature. get first c intersection part
bool zero = false;
for (int i = 0; i < filter_size/2; ++i){
// get intersection of signatures
temp_filter[i] = temp_filter[i] && filter[i];
zero = zero || temp_filter[i];
}
zero = !zero;
if (zero) {
// one section is zero, no possiblility of address in signature
// reset bits we just set
temp_filter[c0 + (filter_size / 2)] = 0;
temp_filter[c1] = 0;
return false;
}
// check second section
zero = false;
for (int i = filter_size / 2; i < filter_size; ++i) {
// get intersection of signatures
temp_filter[i] = temp_filter[i] && filter[i];
zero = zero || temp_filter[i];
}
zero = !zero;
if (zero) {
// one section is zero, no possiblility of address in signature
temp_filter[c0 + (filter_size / 2)] = 0;
temp_filter[c1] = 0;
return false;
}
// one section has at least one bit set
temp_filter[c0 + (filter_size / 2)] = 0;
temp_filter[c1] = 0;
return true;
}
int
Bulk::getCount(Addr addr) const
{
// TODO as in the multi-hashed filters
return 0;
}
Addr
Bulk::hash(Addr addr) const
{
// permutes the original address bits according to Table 5
Addr part1 = bits(addr, offsetBits + 6, offsetBits),
part2 = bits(addr, offsetBits + 9),
part3 = bits(addr, offsetBits + 11),
part4 = bits(addr, offsetBits + 17),
part5 = bits(addr, offsetBits + 8, offsetBits + 7),
part6 = bits(addr, offsetBits + 10),
part7 = bits(addr, offsetBits + 12),
part8 = bits(addr, offsetBits + 13),
part9 = bits(addr, offsetBits + 16, offsetBits + 15),
part10 = bits(addr, offsetBits + 20, offsetBits + 18),
part11 = bits(addr, offsetBits + 14);
Addr result =
(part1 << 14) | (part2 << 13) | (part3 << 12) | (part4 << 11) |
(part5 << 9) | (part6 << 8) | (part7 << 7) | (part8 << 6) |
(part9 << 4) | (part10 << 1) | (part11);
// Select the remaining high-order bits
Addr remaining_bits = bits(addr, std::numeric_limits<Addr>::digits - 1,
offsetBits + 21) << 21;
result = result | remaining_bits;
return result;
}
} // namespace BloomFilter
BloomFilter::Bulk*
BloomFilterBulkParams::create()
{
return new BloomFilter::Bulk(this);
}
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