src/arch/power/predecoder.hh

   1 /*
   2  * Copyright (c) 2006 The Regents of The University of Michigan
   3  * Copyright (c) 2007-2008 The Florida State University
   4  * Copyright (c) 2009 The University of Edinburgh
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions are
   9  * met: redistributions of source code must retain the above copyright
  10  * notice, this list of conditions and the following disclaimer;
  11  * redistributions in binary form must reproduce the above copyright
  12  * notice, this list of conditions and the following disclaimer in the
  13  * documentation and/or other materials provided with the distribution;
  14  * neither the name of the copyright holders nor the names of its
  15  * contributors may be used to endorse or promote products derived from
  16  * this software without specific prior written permission.
  17  *
  18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  29  *
  30  * Authors: Gabe Black
  31  *          Stephen Hines
  32  *          Timothy M. Jones
  33  */
  34
  35 #ifndef __ARCH_ARM_PREDECODER_HH__
  36 #define __ARCH_ARM_PREDECODER_HH__
  37
  38 #include "arch/power/types.hh"
  39 #include "base/misc.hh"
  40 #include "base/types.hh"
  41
  42 class ThreadContext;
  43
  44 namespace PowerISA
  45 {
  46
  47 class Predecoder
  48 {
  49   protected:
  50     ThreadContext * tc;
  51
  52     // The extended machine instruction being generated
  53     ExtMachInst emi;
  54     bool emiIsReady;
  55
  56   public:
  57     Predecoder(ThreadContext * _tc)
  58         : tc(_tc), emiIsReady(false)
  59     {
  60     }
  61
  62     ThreadContext *
  63     getTC()
  64     {
  65         return tc;
  66     }
  67
  68     void
  69     setTC(ThreadContext * _tc)
  70     {
  71         tc = _tc;
  72     }
  73
  74     void
  75     process()
  76     {
  77     }
  78
  79     void
  80     reset()
  81     {
  82         emiIsReady = false;
  83     }
  84
  85     // Use this to give data to the predecoder. This should be used
  86     // when there is control flow.
  87     void
  88     moreBytes(const PCState &pc, Addr fetchPC, MachInst inst)
  89     {
  90         emi = inst;
  91         emiIsReady = true;
  92     }
  93
  94     // Use this to give data to the predecoder. This should be used
  95     // when instructions are executed in order.
  96     void
  97     moreBytes(MachInst machInst)
  98     {
  99         moreBytes(0, 0, machInst);
 100     }
 101
 102     bool
 103     needMoreBytes()
 104     {
 105         return true;
 106     }
 107
 108     bool
 109     extMachInstReady()
 110     {
 111         return emiIsReady;
 112     }
 113
 114     // This returns a constant reference to the ExtMachInst to avoid a copy
 115     const ExtMachInst &
 116     getExtMachInst(PCState &pcState)
 117     {
 118         emiIsReady = false;
 119         return emi;
 120     }
 121 };
 122
 123 } // namespace PowerISA
 124
 125 #endif // __ARCH_POWER_PREDECODER_HH__