d2d581cf01
into zizzer.eecs.umich.edu:/.automount/zamp/z/ktlim2/clean/newmem --HG-- extra : convert_revision : 1d2f499bdc6e21c658a9262da1c8d27d6b74cafe
116 lines
3.5 KiB
C++
116 lines
3.5 KiB
C++
/*
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* Copyright (c) 2005-2006 The Regents of The University of Michigan
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Kevin Lim
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*/
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#ifndef __CPU_O3_SAT_COUNTER_HH__
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#define __CPU_O3_SAT_COUNTER_HH__
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#include "base/misc.hh"
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#include "sim/host.hh"
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/**
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* Private counter class for the internal saturating counters.
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* Implements an n bit saturating counter and provides methods to
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* increment, decrement, and read it.
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* @todo Consider making this something that more closely mimics a
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* built in class so you can use ++ or --.
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*/
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class SatCounter
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{
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public:
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/**
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* Constructor for the counter.
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*/
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SatCounter()
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: initialVal(0), counter(0)
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{ }
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/**
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* Constructor for the counter.
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* @param bits How many bits the counter will have.
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*/
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SatCounter(unsigned bits)
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: initialVal(0), maxVal((1 << bits) - 1), counter(0)
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{ }
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/**
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* Constructor for the counter.
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* @param bits How many bits the counter will have.
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* @param initial_val Starting value for each counter.
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*/
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SatCounter(unsigned bits, uint8_t initial_val)
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: initialVal(initialVal), maxVal((1 << bits) - 1), counter(initial_val)
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{
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// Check to make sure initial value doesn't exceed the max
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// counter value.
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if (initial_val > maxVal) {
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fatal("BP: Initial counter value exceeds max size.");
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}
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}
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/**
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* Sets the number of bits.
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*/
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void setBits(unsigned bits) { maxVal = (1 << bits) - 1; }
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void reset() { counter = initialVal; }
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/**
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* Increments the counter's current value.
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*/
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void increment()
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{
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if (counter < maxVal) {
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++counter;
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}
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}
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/**
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* Decrements the counter's current value.
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*/
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void decrement()
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{
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if (counter > 0) {
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--counter;
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}
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}
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/**
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* Read the counter's value.
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*/
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const uint8_t read() const
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{ return counter; }
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private:
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uint8_t initialVal;
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uint8_t maxVal;
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uint8_t counter;
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};
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#endif // __CPU_O3_SAT_COUNTER_HH__
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