decode_cache.hh

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/*
 * Copyright (c) 2011 Google
 * All rights reserved.
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 * modification, are permitted provided that the following conditions are
 * met: redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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#ifndef __ARCH_GENERIC_DECODE_CACHE_HH__
#define __ARCH_GENERIC_DECODE_CACHE_HH__
 
#include "base/types.hh"
#include "cpu/decode_cache.hh"
#include "cpu/static_inst_fwd.hh"
 
namespace gem5
{
 
namespace GenericISA
{
 
template <typename Decoder, typename EMI>
class BasicDecodeCache
{
  private:
    decode_cache::InstMap<EMI> instMap;
    struct AddrMapEntry
    {
        StaticInstPtr inst;
        EMI machInst;
    };
    decode_cache::AddrMap<AddrMapEntry> decodePages;
 
  public:
    StaticInstPtr
    decode(Decoder *const decoder, EMI mach_inst, Addr addr)
    {
        auto &entry = decodePages.lookup(addr);
        if (entry.inst && (entry.machInst == mach_inst))
            return entry.inst;
 
        entry.machInst = mach_inst;
 
        auto iter = instMap.find(mach_inst);
        if (iter != instMap.end()) {
            entry.inst = iter->second;
            return entry.inst;
        }
 
        entry.inst = decoder->decodeInst(mach_inst);
        instMap[mach_inst] = entry.inst;
        return entry.inst;
    }
};
 
} // namespace GenericISA
} // namespace gem5
 
#endif // __ARCH_GENERIC_DECODE_CACHE_HH__