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     class Predecoder
  44     {
  45       protected:
  46         ThreadContext * tc;
  47         //The extended machine instruction being generated
  48         ExtMachInst emi;
  49
  50       public:
  51         Predecoder(ThreadContext * _tc) : tc(_tc)
  52         {}
  53
  54         ThreadContext * getTC()
  55         {
  56             return tc;
  57         }
  58
  59         void setTC(ThreadContext * _tc)
  60         {
  61             tc = _tc;
  62         }
  63
  64         void process()
  65         {
  66         }
  67
  68         void reset()
  69         {}
  70
  71         //Use this to give data to the predecoder. This should be used
  72         //when there is control flow.
  73         void moreBytes(Addr pc, Addr fetchPC, MachInst inst)
  74         {
  75             emi = inst;
  76         }
  77
  78         bool needMoreBytes()
  79         {
  80             return true;
  81         }
  82
  83         bool extMachInstReady()
  84         {
  85             return true;
  86         }
  87
  88         //This returns a constant reference to the ExtMachInst to avoid a copy
  89         const ExtMachInst & getExtMachInst()
  90         {
  91             return emi;
  92         }
  93     };
  94 };
  95
  96 #endif // __ARCH_MIPS_PREDECODER_HH__