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/*
* Copyright (c) 2012 Advanced Micro Devices, Inc.
* 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.
*
* Author: Brad Beckmann
*
*/
#include "base/intmath.hh"
#include "mem/ruby/structures/BankedArray.hh"
#include "mem/ruby/system/System.hh"
BankedArray::BankedArray(unsigned int banks, Cycles accessLatency,
unsigned int startIndexBit, RubySystem *rs)
: m_ruby_system(rs)
{
this->banks = banks;
this->accessLatency = accessLatency;
this->startIndexBit = startIndexBit;
if (banks != 0) {
bankBits = floorLog2(banks);
}
busyBanks.resize(banks);
}
bool
BankedArray::tryAccess(int64 idx)
{
if (accessLatency == 0)
return true;
unsigned int bank = mapIndexToBank(idx);
assert(bank < banks);
if (busyBanks[bank].endAccess >= curTick()) {
return false;
}
return true;
}
void
BankedArray::reserve(int64 idx)
{
if (accessLatency == 0)
return;
unsigned int bank = mapIndexToBank(idx);
assert(bank < banks);
if(busyBanks[bank].endAccess >= curTick()) {
if (busyBanks[bank].startAccess == curTick() &&
busyBanks[bank].idx == idx) {
// this is the same reservation (can happen when
// e.g., reserve the same resource for read and write)
return; // OK
} else {
panic("BankedArray reservation error");
}
}
busyBanks[bank].idx = idx;
busyBanks[bank].startAccess = curTick();
busyBanks[bank].endAccess = curTick() +
(accessLatency-1) * m_ruby_system->clockPeriod();
}
unsigned int
BankedArray::mapIndexToBank(int64 idx)
{
if (banks == 1) {
return 0;
}
return idx % banks;
}
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