| /* |
| * Copyright (c) 2007 The Hewlett-Packard Development Company |
| * All rights reserved. |
| * |
| * Redistribution and use of this software in source and binary forms, |
| * with or without modification, are permitted provided that the |
| * following conditions are met: |
| * |
| * The software must be used only for Non-Commercial Use which means any |
| * use which is NOT directed to receiving any direct monetary |
| * compensation for, or commercial advantage from such use. Illustrative |
| * examples of non-commercial use are academic research, personal study, |
| * teaching, education and corporate research & development. |
| * Illustrative examples of commercial use are distributing products for |
| * commercial advantage and providing services using the software for |
| * commercial advantage. |
| * |
| * If you wish to use this software or functionality therein that may be |
| * covered by patents for commercial use, please contact: |
| * Director of Intellectual Property Licensing |
| * Office of Strategy and Technology |
| * Hewlett-Packard Company |
| * 1501 Page Mill Road |
| * Palo Alto, California 94304 |
| * |
| * 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 HOLDER(s), HEWLETT-PACKARD COMPANY, nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. No right of |
| * sublicense is granted herewith. Derivatives of the software and |
| * output created using the software may be prepared, but only for |
| * Non-Commercial Uses. Derivatives of the software may be shared with |
| * others provided: (i) the others agree to abide by the list of |
| * conditions herein which includes the Non-Commercial Use restrictions; |
| * and (ii) such Derivatives of the software include the above copyright |
| * notice to acknowledge the contribution from this software where |
| * applicable, this list of conditions and the disclaimer below. |
| * |
| * 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_X86_PREDECODER_HH__ |
| #define __ARCH_X86_PREDECODER_HH__ |
| |
| #include <cassert> |
| |
| #include "arch/x86/types.hh" |
| #include "arch/x86/miscregs.hh" |
| #include "base/bitfield.hh" |
| #include "base/misc.hh" |
| #include "base/trace.hh" |
| #include "base/types.hh" |
| |
| class ThreadContext; |
| |
| namespace X86ISA |
| { |
| class Predecoder |
| { |
| private: |
| //These are defined and documented in predecoder_tables.cc |
| static const uint8_t Prefixes[256]; |
| static const uint8_t UsesModRM[2][256]; |
| static const uint8_t ImmediateType[2][256]; |
| static const uint8_t SizeTypeToSize[3][10]; |
| |
| protected: |
| ThreadContext * tc; |
| //The bytes to be predecoded |
| MachInst fetchChunk; |
| //The pc of the start of fetchChunk |
| Addr basePC; |
| //The pc the current instruction started at |
| Addr origPC; |
| //The offset into fetchChunk of current processing |
| int offset; |
| //The extended machine instruction being generated |
| ExtMachInst emi; |
| HandyM5Reg m5Reg; |
| |
| inline uint8_t getNextByte() |
| { |
| return ((uint8_t *)&fetchChunk)[offset]; |
| } |
| |
| void getImmediate(int &collected, uint64_t ¤t, int size) |
| { |
| //Figure out how many bytes we still need to get for the |
| //immediate. |
| int toGet = size - collected; |
| //Figure out how many bytes are left in our "buffer" |
| int remaining = sizeof(MachInst) - offset; |
| //Get as much as we need, up to the amount available. |
| toGet = toGet > remaining ? remaining : toGet; |
| |
| //Shift the bytes we want to be all the way to the right |
| uint64_t partialImm = fetchChunk >> (offset * 8); |
| //Mask off what we don't want |
| partialImm &= mask(toGet * 8); |
| //Shift it over to overlay with our displacement. |
| partialImm <<= (immediateCollected * 8); |
| //Put it into our displacement |
| current |= partialImm; |
| //Update how many bytes we've collected. |
| collected += toGet; |
| consumeBytes(toGet); |
| } |
| |
| inline void consumeByte() |
| { |
| offset++; |
| assert(offset <= sizeof(MachInst)); |
| if(offset == sizeof(MachInst)) |
| outOfBytes = true; |
| } |
| |
| inline void consumeBytes(int numBytes) |
| { |
| offset += numBytes; |
| assert(offset <= sizeof(MachInst)); |
| if(offset == sizeof(MachInst)) |
| outOfBytes = true; |
| } |
| |
| void doReset(); |
| |
| //State machine state |
| protected: |
| //Whether or not we're out of bytes |
| bool outOfBytes; |
| //Whether we've completed generating an ExtMachInst |
| bool emiIsReady; |
| //The size of the displacement value |
| int displacementSize; |
| //The size of the immediate value |
| int immediateSize; |
| //This is how much of any immediate value we've gotten. This is used |
| //for both the actual immediate and the displacement. |
| int immediateCollected; |
| |
| enum State { |
| ResetState, |
| PrefixState, |
| OpcodeState, |
| ModRMState, |
| SIBState, |
| DisplacementState, |
| ImmediateState, |
| //We should never get to this state. Getting here is an error. |
| ErrorState |
| }; |
| |
| State state; |
| |
| //Functions to handle each of the states |
| State doPrefixState(uint8_t); |
| State doOpcodeState(uint8_t); |
| State doModRMState(uint8_t); |
| State doSIBState(uint8_t); |
| State doDisplacementState(); |
| State doImmediateState(); |
| |
| public: |
| Predecoder(ThreadContext * _tc) : |
| tc(_tc), basePC(0), origPC(0), offset(0), |
| outOfBytes(true), emiIsReady(false), |
| state(ResetState) |
| { |
| emi.mode.mode = LongMode; |
| emi.mode.submode = SixtyFourBitMode; |
| m5Reg = 0; |
| } |
| |
| void reset() |
| { |
| state = ResetState; |
| } |
| |
| ThreadContext * getTC() |
| { |
| return tc; |
| } |
| |
| void setTC(ThreadContext * _tc) |
| { |
| tc = _tc; |
| } |
| |
| void process(); |
| |
| //Use this to give data to the predecoder. This should be used |
| //when there is control flow. |
| void moreBytes(Addr pc, Addr fetchPC, MachInst data) |
| { |
| DPRINTF(Predecoder, "Getting more bytes.\n"); |
| basePC = fetchPC; |
| offset = (fetchPC >= pc) ? 0 : pc - fetchPC; |
| fetchChunk = data; |
| outOfBytes = false; |
| process(); |
| } |
| |
| 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; |
| } |
| |
| int getInstSize() |
| { |
| DPRINTF(Predecoder, |
| "Calculating the instruction size: " |
| "basePC: %#x offset: %#x origPC: %#x\n", |
| basePC, offset, origPC); |
| return basePC + offset - origPC; |
| } |
| }; |
| }; |
| |
| #endif // __ARCH_X86_PREDECODER_HH__ |