fc57ae6401
The changes made by the changeset 270c9a75e91f do not work well with switching of cpus. The problem is that decoder for the old thread context holds state that is not taken over by the new decoder. This patch adds a takeOverFrom() function to Decoder class in each ISA. Except for x86, functions in other ISAs are blank. For x86, the function copies state from the old decoder to the new decoder.
160 lines
4.3 KiB
C++
160 lines
4.3 KiB
C++
/*
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* Copyright (c) 2012 Google
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are
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* met: redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer;
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* redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution;
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* neither the name of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* Authors: Gabe Black
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*/
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#ifndef __ARCH_ARM_DECODER_HH__
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#define __ARCH_ARM_DECODER_HH__
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#include <cassert>
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#include "arch/arm/miscregs.hh"
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#include "arch/arm/types.hh"
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#include "arch/generic/decode_cache.hh"
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#include "base/types.hh"
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#include "cpu/static_inst.hh"
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namespace ArmISA
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{
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class Decoder
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{
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protected:
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//The extended machine instruction being generated
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ExtMachInst emi;
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MachInst data;
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bool bigThumb;
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bool instDone;
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bool outOfBytes;
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int offset;
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bool foundIt;
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ITSTATE itBits;
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int fpscrLen;
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int fpscrStride;
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public:
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void reset()
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{
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bigThumb = false;
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offset = 0;
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emi = 0;
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instDone = false;
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outOfBytes = true;
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foundIt = false;
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}
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Decoder() : data(0), fpscrLen(0), fpscrStride(0)
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{
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reset();
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}
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void process();
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//Use this to give data to the decoder. This should be used
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//when there is control flow.
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void moreBytes(const PCState &pc, Addr fetchPC, MachInst inst);
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//Use this to give data to the decoder. This should be used
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//when instructions are executed in order.
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void moreBytes(MachInst machInst)
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{
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moreBytes(0, 0, machInst);
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}
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inline void consumeBytes(int numBytes)
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{
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offset += numBytes;
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assert(offset <= sizeof(MachInst));
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if (offset == sizeof(MachInst))
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outOfBytes = true;
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}
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bool needMoreBytes() const
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{
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return outOfBytes;
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}
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bool instReady() const
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{
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return instDone;
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}
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int getInstSize() const
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{
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return (!emi.thumb || emi.bigThumb) ? 4 : 2;
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}
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void setContext(FPSCR fpscr)
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{
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fpscrLen = fpscr.len;
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fpscrStride = fpscr.stride;
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}
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void takeOverFrom(Decoder *old) {}
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protected:
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/// A cache of decoded instruction objects.
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static GenericISA::BasicDecodeCache defaultCache;
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public:
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StaticInstPtr decodeInst(ExtMachInst mach_inst);
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/// Decode a machine instruction.
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/// @param mach_inst The binary instruction to decode.
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/// @retval A pointer to the corresponding StaticInst object.
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StaticInstPtr
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decode(ExtMachInst mach_inst, Addr addr)
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{
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return defaultCache.decode(this, mach_inst, addr);
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}
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StaticInstPtr
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decode(ArmISA::PCState &nextPC)
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{
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if (!instDone)
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return NULL;
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assert(instDone);
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ExtMachInst thisEmi = emi;
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nextPC.npc(nextPC.pc() + getInstSize());
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if (foundIt)
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nextPC.nextItstate(itBits);
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thisEmi.itstate = nextPC.itstate();
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nextPC.size(getInstSize());
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emi = 0;
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instDone = false;
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foundIt = false;
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return decode(thisEmi, nextPC.instAddr());
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}
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};
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} // namespace ArmISA
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#endif // __ARCH_ARM_DECODER_HH__
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