src/cpu/o3/sat_counter.hh

   1 /*
   2  * Copyright (c) 2005 The Regents of The University of Michigan
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions are
   7  * met: redistributions of source code must retain the above copyright
   8  * notice, this list of conditions and the following disclaimer;
   9  * redistributions in binary form must reproduce the above copyright
  10  * notice, this list of conditions and the following disclaimer in the
  11  * documentation and/or other materials provided with the distribution;
  12  * neither the name of the copyright holders nor the names of its
  13  * contributors may be used to endorse or promote products derived from
  14  * this software without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  17  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  18  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  19  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  20  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  21  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  22  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  26  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  *
  28  * Authors: Kevin Lim
  29  */
  30
  31 #ifndef __CPU_O3_CPU_SAT_COUNTER_HH__
  32 #define __CPU_O3_CPU_SAT_COUNTER_HH__
  33
  34 #include "sim/host.hh"
  35
  36 /**
  37  * Private counter class for the internal saturating counters.
  38  * Implements an n bit saturating counter and provides methods to
  39  * increment, decrement, and read it.
  40  * @todo Consider making this something that more closely mimics a
  41  * built in class so you can use ++ or --.
  42  */
  43 class SatCounter
  44 {
  45   public:
  46     /**
  47      * Constructor for the counter.
  48      */
  49     SatCounter();
  50
  51     /**
  52      * Constructor for the counter.
  53      * @param bits How many bits the counter will have.
  54      */
  55     SatCounter(unsigned bits);
  56
  57     /**
  58      * Constructor for the counter.
  59      * @param bits How many bits the counter will have.
  60      * @param initial_val Starting value for each counter.
  61      */
  62     SatCounter(unsigned bits, unsigned initial_val);
  63
  64     /**
  65      * Sets the number of bits.
  66      */
  67     void setBits(unsigned bits);
  68
  69     /**
  70      * Increments the counter's current value.
  71      */
  72     void increment();
  73
  74     /**
  75      * Decrements the counter's current value.
  76      */
  77     void decrement();
  78
  79     /**
  80      * Read the counter's value.
  81      */
  82     const uint8_t read() const
  83     {
  84         return counter;
  85     }
  86
  87   private:
  88     uint8_t maxVal;
  89     uint8_t counter;
  90 };
  91
  92 #endif // __CPU_O3_CPU_SAT_COUNTER_HH__