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/*
* Copyright (c) 2012 Google
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* 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
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* Authors: Gabe Black
*/
#ifndef __ARCH_ALPHA_DECODER_HH__
#define __ARCH_ALPHA_DECODER_HH__
#include "arch/generic/decode_cache.hh"
#include "arch/types.hh"
#include "cpu/static_inst.hh"
#include "sim/full_system.hh"
namespace AlphaISA
{
class ISA;
class Decoder
{
protected:
// The extended machine instruction being generated
ExtMachInst ext_inst;
bool instDone;
public:
Decoder(ISA* isa = nullptr) : instDone(false)
{}
void
process()
{ }
void
reset()
{
instDone = false;
}
// Use this to give data to the predecoder. This should be used
// when there is control flow.
void
moreBytes(const PCState &pc, Addr fetchPC, MachInst inst)
{
ext_inst = inst;
instDone = true;
if (FullSystem)
ext_inst |= (static_cast<ExtMachInst>(pc.pc() & 0x1) << 32);
}
bool
needMoreBytes()
{
return true;
}
bool
instReady()
{
return instDone;
}
void takeOverFrom(Decoder * old) {}
protected:
/// A cache of decoded instruction objects.
static GenericISA::BasicDecodeCache defaultCache;
public:
StaticInstPtr decodeInst(ExtMachInst mach_inst);
/// Decode a machine instruction.
/// @param mach_inst The binary instruction to decode.
/// @retval A pointer to the corresponding StaticInst object.
StaticInstPtr
decode(ExtMachInst mach_inst, Addr addr)
{
return defaultCache.decode(this, mach_inst, addr);
}
StaticInstPtr
decode(AlphaISA::PCState &nextPC)
{
if (!instDone)
return NULL;
instDone = false;
return decode(ext_inst, nextPC.instAddr());
}
};
} // namespace AlphaISA
#endif // __ARCH_ALPHA_DECODER_HH__
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