src/cpu/pred/ras.cc

   1 /*
   2  * Copyright (c) 2004-2005 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
  29 #include "cpu/pred/ras.hh"
  30
  31 void
  32 ReturnAddrStack::init(unsigned _numEntries)
  33 {
  34      numEntries  = _numEntries;
  35      addrStack.resize(numEntries);
  36      reset();
  37 }
  38
  39 void
  40 ReturnAddrStack::reset()
  41 {
  42     usedEntries = 0;
  43     tos = 0;
  44     for (unsigned i = 0; i < numEntries; ++i)
  45         addrStack[i].set(0);
  46 }
  47
  48 void
  49 ReturnAddrStack::push(const TheISA::PCState &return_addr)
  50 {
  51     incrTos();
  52
  53     addrStack[tos] = return_addr;
  54
  55     if (usedEntries != numEntries) {
  56         ++usedEntries;
  57     }
  58 }
  59
  60 void
  61 ReturnAddrStack::pop()
  62 {
  63     if (usedEntries > 0) {
  64         --usedEntries;
  65     }
  66
  67     decrTos();
  68 }
  69
  70 void
  71 ReturnAddrStack::restore(unsigned top_entry_idx,
  72                          const TheISA::PCState &restored)
  73 {
  74     tos = top_entry_idx;
  75
  76     addrStack[tos] = restored;
  77
  78     if (usedEntries != numEntries) {
  79         ++usedEntries;
  80     }
  81 }