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
  55   public:
  56     Predecoder(ThreadContext * _tc)
  57         : tc(_tc)
  58     {
  59     }
  60
  61     ThreadContext *
  62     getTC()
  63     {
  64         return tc;
  65     }
  66
  67     void
  68     setTC(ThreadContext * _tc)
  69     {
  70         tc = _tc;
  71     }
  72
  73     void
  74     process()
  75     {
  76     }
  77
  78     void
  79     reset()
  80     {
  81     }
  82
  83     // Use this to give data to the predecoder. This should be used
  84     // when there is control flow.
  85     void
  86     moreBytes(Addr pc, Addr fetchPC, MachInst inst)
  87     {
  88         emi = inst;
  89     }
  90
  91     // Use this to give data to the predecoder. This should be used
  92     // when instructions are executed in order.
  93     void
  94     moreBytes(MachInst machInst)
  95     {
  96         moreBytes(0, 0, machInst);
  97     }
  98
  99     bool
 100     needMoreBytes()
 101     {
 102         return true;
 103     }
 104
 105     bool
 106     extMachInstReady()
 107     {
 108         return true;
 109     }
 110
 111     // This returns a constant reference to the ExtMachInst to avoid a copy
 112     const ExtMachInst &
 113     getExtMachInst()
 114     {
 115         return emi;
 116     }
 117 };
 118
 119 } // PowerISA namespace
 120
 121 #endif // __ARCH_POWER_PREDECODER_HH__