src/arch/mips/predecoder.hh

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