2007-03-15 03:47:42 +01:00
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/*
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* Copyright (c) 2007 The Hewlett-Packard Development Company
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* All rights reserved.
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*
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* Redistribution and use of this software in source and binary forms,
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* with or without modification, are permitted provided that the
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* following conditions are met:
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*
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* The software must be used only for Non-Commercial Use which means any
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* use which is NOT directed to receiving any direct monetary
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* compensation for, or commercial advantage from such use. Illustrative
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* examples of non-commercial use are academic research, personal study,
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* teaching, education and corporate research & development.
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* Illustrative examples of commercial use are distributing products for
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* commercial advantage and providing services using the software for
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* commercial advantage.
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*
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* If you wish to use this software or functionality therein that may be
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* covered by patents for commercial use, please contact:
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* Director of Intellectual Property Licensing
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* Office of Strategy and Technology
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* Hewlett-Packard Company
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* 1501 Page Mill Road
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* Palo Alto, California 94304
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*
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* Redistributions of source code must retain the above copyright notice,
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* this list of conditions and the following disclaimer. Redistributions
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* in binary form must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or
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* other materials provided with the distribution. Neither the name of
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* the COPYRIGHT HOLDER(s), HEWLETT-PACKARD COMPANY, 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. No right of
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* sublicense is granted herewith. Derivatives of the software and
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* output created using the software may be prepared, but only for
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* Non-Commercial Uses. Derivatives of the software may be shared with
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* others provided: (i) the others agree to abide by the list of
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* conditions herein which includes the Non-Commercial Use restrictions;
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* and (ii) such Derivatives of the software include the above copyright
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* notice to acknowledge the contribution from this software where
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* applicable, this list of conditions and the disclaimer below.
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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_X86_PREDECODER_HH__
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#define __ARCH_X86_PREDECODER_HH__
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#include "arch/x86/types.hh"
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#include "base/bitfield.hh"
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#include "base/misc.hh"
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#include "sim/host.hh"
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class ThreadContext;
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namespace X86ISA
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{
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class Predecoder
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{
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private:
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2007-03-15 16:29:39 +01:00
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//These are defined and documented in predecoder_tables.cc
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2007-03-15 03:47:42 +01:00
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static const uint8_t Prefixes[256];
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static const uint8_t UsesModRM[2][256];
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2007-03-15 16:29:39 +01:00
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static const uint8_t ImmediateType[2][256];
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static const uint8_t ImmediateTypeToSize[3][10];
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2007-03-15 03:47:42 +01:00
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protected:
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ThreadContext * tc;
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//The bytes to be predecoded
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MachInst fetchChunk;
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//The pc of the start of fetchChunk
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Addr basePC;
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//The offset into fetchChunk of current processing
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int offset;
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//The extended machine instruction being generated
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ExtMachInst emi;
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//State machine state
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protected:
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//Whether or not we're out of bytes
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bool outOfBytes;
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//Whether we've completed generating an ExtMachInst
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bool emiIsReady;
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//The size of the displacement value
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int displacementSize;
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int displacementCollected;
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//The size of the immediate value
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int immediateSize;
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int immediateCollected;
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//These are local to some of the states. I need to turn the states
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//into inline functions to clean things up a bit.
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int toGet;
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int remaining;
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MachInst partialDisp;
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enum State {
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Prefix,
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Opcode,
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ModRM,
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SIB,
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Displacement,
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Immediate
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};
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State state;
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public:
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Predecoder(ThreadContext * _tc) :
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tc(_tc), basePC(0), offset(0),
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outOfBytes(true), emiIsReady(false),
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state(Prefix)
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{}
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ThreadContext * getTC()
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{
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return tc;
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}
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void setTC(ThreadContext * _tc)
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{
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tc = _tc;
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}
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void process()
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{
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warn("About to process some bytes\n");
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assert(!outOfBytes);
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assert(!emiIsReady);
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while(!emiIsReady && !outOfBytes)
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{
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uint8_t nextByte = (fetchChunk >> (offset * 8)) & 0xff;
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switch(state)
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{
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case Prefix:
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uint8_t prefix = Prefixes[nextByte];
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switch(prefix)
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{
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//Operand size override prefixes
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case OperandSizeOverride:
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warn("Found operand size override prefix!\n");
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offset++;
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break;
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case AddressSizeOverride:
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warn("Found address size override prefix!\n");
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offset++;
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break;
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//Segment override prefixes
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case CSOverride:
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warn("Found cs segment override!\n");
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offset++;
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break;
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case DSOverride:
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warn("Found ds segment override!\n");
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offset++;
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break;
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case ESOverride:
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warn("Found es segment override!\n");
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offset++;
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break;
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case FSOverride:
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warn("Found fs segment override!\n");
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offset++;
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break;
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case GSOverride:
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warn("Found gs segment override!\n");
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offset++;
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break;
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case SSOverride:
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warn("Found ss segment override!\n");
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offset++;
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break;
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case Lock:
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warn("Found lock prefix!\n");
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offset++;
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break;
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case Rep:
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warn("Found rep prefix!\n");
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offset++;
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break;
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case Repne:
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warn("Found repne prefix!\n");
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offset++;
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break;
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case Rex:
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warn("Found Rex prefix %#x!\n", nextByte);
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2007-03-15 16:29:39 +01:00
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emi.rexPrefix = nextByte;
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2007-03-15 03:47:42 +01:00
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offset++;
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break;
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case 0:
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2007-03-15 16:29:39 +01:00
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emi.numOpcodes = 0;
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2007-03-15 03:47:42 +01:00
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state = Opcode;
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break;
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default:
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panic("Unrecognized prefix %#x\n", nextByte);
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}
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break;
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case Opcode:
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2007-03-15 16:29:39 +01:00
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emi.numOpcodes++;
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assert(emi.numOpcodes < 2);
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2007-03-15 03:47:42 +01:00
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if(nextByte == 0xf0)
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{
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warn("Found two byte opcode!\n");
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}
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else
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{
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2007-03-15 16:29:39 +01:00
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immediateCollected = 0;
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displacementCollected = 0;
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emi.immediate = 0;
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emi.displacement = 0;
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int immType = ImmediateType[
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emi.numOpcodes - 1][nextByte];
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if(0) //16 bit mode
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immediateSize = ImmediateTypeToSize[0][immType];
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else if(!(emi.rexPrefix & 0x4)) //32 bit mode
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immediateSize = ImmediateTypeToSize[1][immType];
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else //64 bit mode
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immediateSize = ImmediateTypeToSize[2][immType];
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2007-03-15 03:47:42 +01:00
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warn("Found opcode %#x!\n", nextByte);
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2007-03-15 16:29:39 +01:00
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if (UsesModRM[emi.numOpcodes - 1][nextByte]) {
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2007-03-15 03:47:42 +01:00
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state = ModRM;
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2007-03-15 16:29:39 +01:00
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} else if(immediateSize) {
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2007-03-15 03:47:42 +01:00
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state = Immediate;
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} else {
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emiIsReady = true;
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state = Prefix;
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}
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}
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offset++;
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break;
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case ModRM:
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warn("Found modrm byte %#x!\n", nextByte);
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if (0) {//in 16 bit mode
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//figure out 16 bit displacement size
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if(nextByte & 0xC7 == 0x06 ||
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2007-03-15 16:29:39 +01:00
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nextByte & 0xC0 == 0x80)
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2007-03-15 03:47:42 +01:00
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displacementSize = 2;
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2007-03-15 16:29:39 +01:00
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else if(nextByte & 0xC0 == 0x40)
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displacementSize = 1;
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2007-03-15 03:47:42 +01:00
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else
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displacementSize = 0;
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} else {
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//figure out 32/64 bit displacement size
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2007-03-15 16:29:39 +01:00
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if(nextByte & 0xC7 == 0x05 ||
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nextByte & 0xC0 == 0x80)
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2007-03-15 03:47:42 +01:00
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displacementSize = 4;
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2007-03-15 16:29:39 +01:00
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else if(nextByte & 0xC0 == 0x40)
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2007-03-15 03:47:42 +01:00
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displacementSize = 2;
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else
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2007-03-15 16:29:39 +01:00
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displacementSize = 0;
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2007-03-15 03:47:42 +01:00
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}
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//If there's an SIB, get that next.
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//There is no SIB in 16 bit mode.
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if(nextByte & 0x7 == 4 &&
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nextByte & 0xC0 != 0xC0) {
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// && in 32/64 bit mode)
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state = SIB;
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} else if(displacementSize) {
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state = Displacement;
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} else if(immediateSize) {
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state = Immediate;
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} else {
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emiIsReady = true;
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state = Prefix;
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}
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//The ModRM byte is consumed no matter what
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offset++;
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break;
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case SIB:
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warn("Found SIB byte %#x!\n", nextByte);
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offset++;
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if(displacementSize) {
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state = Displacement;
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} else if(immediateSize) {
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state = Immediate;
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} else {
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emiIsReady = true;
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state = Prefix;
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}
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break;
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case Displacement:
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//Gather up the displacement, or at least as much of it
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//as we can get.
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//Figure out how many bytes we still need to get for the
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//displacement.
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toGet = displacementSize - displacementCollected;
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//Figure out how many bytes are left in our "buffer"
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remaining = sizeof(MachInst) - offset;
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//Get as much as we need, up to the amount available.
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toGet = toGet > remaining ? remaining : toGet;
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//Shift the bytes we want to be all the way to the right
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partialDisp = fetchChunk >> offset;
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//Mask off what we don't want
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partialDisp &= mask(toGet * 8);
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//Shift it over to overlay with our displacement.
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partialDisp <<= displacementCollected;
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//Put it into our displacement
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emi.displacement |= partialDisp;
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//Update how many bytes we've collected.
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displacementCollected += toGet;
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2007-03-15 16:29:39 +01:00
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offset += toGet;
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warn("Collecting %d byte displacement, got %d bytes!\n",
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displacementSize, toGet);
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2007-03-15 03:47:42 +01:00
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if(displacementSize == displacementCollected) {
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//Sign extend the displacement
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switch(displacementSize)
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{
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case 1:
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emi.displacement = sext<8>(emi.displacement);
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break;
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case 2:
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emi.displacement = sext<16>(emi.displacement);
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break;
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case 4:
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emi.displacement = sext<32>(emi.displacement);
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break;
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default:
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panic("Undefined displacement size!\n");
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}
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if(immediateSize) {
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state = Immediate;
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} else {
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emiIsReady = true;
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state = Prefix;
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}
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}
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break;
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case Immediate:
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//Gather up the displacement, or at least as much of it
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//as we can get
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//Figure out how many bytes we still need to get for the
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//immediate.
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toGet = immediateSize - immediateCollected;
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//Figure out how many bytes are left in our "buffer"
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remaining = sizeof(MachInst) - offset;
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//Get as much as we need, up to the amount available.
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toGet = toGet > remaining ? remaining : toGet;
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//Shift the bytes we want to be all the way to the right
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partialDisp = fetchChunk >> offset;
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//Mask off what we don't want
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partialDisp &= mask(toGet * 8);
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//Shift it over to overlay with our immediate.
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2007-03-15 16:29:39 +01:00
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partialDisp <<= immediateCollected;
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2007-03-15 03:47:42 +01:00
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//Put it into our immediate
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2007-03-15 16:29:39 +01:00
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emi.immediate |= partialDisp;
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2007-03-15 03:47:42 +01:00
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//Update how many bytes we've collected.
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2007-03-15 16:29:39 +01:00
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immediateCollected += toGet;
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offset += toGet;
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warn("Collecting %d byte immediate, got %d bytes!\n",
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immediateSize, toGet);
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|
|
2007-03-15 03:47:42 +01:00
|
|
|
if(immediateSize == immediateCollected)
|
|
|
|
{
|
|
|
|
emiIsReady = true;
|
|
|
|
state = Prefix;
|
|
|
|
}
|
|
|
|
break;
|
|
|
|
default:
|
|
|
|
panic("Unrecognized state! %d\n", state);
|
|
|
|
}
|
|
|
|
if(offset == sizeof(MachInst))
|
|
|
|
outOfBytes = true;
|
|
|
|
}
|
|
|
|
}
|
|
|
|
|
|
|
|
//Use this to give data to the predecoder. This should be used
|
|
|
|
//when there is control flow.
|
|
|
|
void moreBytes(Addr currPC, Addr off, MachInst data)
|
|
|
|
{
|
|
|
|
basePC = currPC;
|
|
|
|
offset = off;
|
|
|
|
fetchChunk = data;
|
|
|
|
assert(off < sizeof(MachInst));
|
|
|
|
outOfBytes = false;
|
|
|
|
warn("About to call process.\n");
|
|
|
|
process();
|
|
|
|
}
|
|
|
|
|
|
|
|
//Use this to give data to the predecoder. This should be used
|
|
|
|
//when instructions are executed in order.
|
|
|
|
void moreBytes(MachInst machInst)
|
|
|
|
{
|
|
|
|
moreBytes(basePC + sizeof(machInst), 0, machInst);
|
|
|
|
}
|
|
|
|
|
|
|
|
bool needMoreBytes()
|
|
|
|
{
|
|
|
|
return outOfBytes;
|
|
|
|
}
|
|
|
|
|
|
|
|
bool extMachInstReady()
|
|
|
|
{
|
|
|
|
return emiIsReady;
|
|
|
|
}
|
|
|
|
|
|
|
|
//This returns a constant reference to the ExtMachInst to avoid a copy
|
|
|
|
const ExtMachInst & getExtMachInst()
|
|
|
|
{
|
|
|
|
assert(emiIsReady);
|
|
|
|
emiIsReady = false;
|
|
|
|
return emi;
|
|
|
|
}
|
|
|
|
};
|
|
|
|
};
|
|
|
|
|
|
|
|
#endif // __ARCH_X86_PREDECODER_HH__
|