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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 <limits>
#include "base/bitfield.hh"
#include "base/logging.hh"
#include "params/BloomFilterBulk.hh"
namespace BloomFilter {
Bulk::Bulk(const BloomFilterBulkParams* p)
: MultiBitSel(p), sectorBits(floorLog2(parFilterSize))
{
fatal_if((numHashes * sectorBits) >
(std::numeric_limits<Addr>::digits - offsetBits),
"Sectors need more bits than available");
}
Bulk::~Bulk()
{
}
int
Bulk::hash(Addr addr, int hash_number) const
{
addr = permute(addr);
// Get the sector-based c index
int c = bits(addr, (offsetBits + (hash_number + 1) * sectorBits) - 1,
offsetBits + hash_number * sectorBits);
assert(c < filter.size()/numHashes);
// Transform the sector-based c index into a filder index (v)
c += (numHashes - 1 - hash_number) * (filter.size()/numHashes);
assert(c < filter.size());
return c;
}
Addr
Bulk::permute(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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