AOutTextSectionReader.cc

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/*
    Copyright (c) 2002-2009 Tampere University.
 
    This file is part of TTA-Based Codesign Environment (TCE).
 
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/**
 * @file AOutTextSectionReader.cc
 *
 * Definition of AOutTextSectionReader class.
 *
 * @author Jussi Nykänen 2003 (nykanen-no.spam-cs.tut.fi)
 * @author Mikael Lepistö 2003 (tmlepist-no.spam-cs.tut.fi)
 * @note reviewed 23 October 2003 by pj, am, ll, jn
 *
 * @note rating: yellow
 */
 
#include "AOutTextSectionReader.hh"
#include "SafePointer.hh"
#include "AOutSymbolSectionReader.hh"
#include "ReferenceKey.hh"
#include "SectionReader.hh"
#include "Conversion.hh"
#include "ResourceSection.hh"
#include "MoveElement.hh"
#include "ImmediateElement.hh"
 
namespace TPEF {
 
using std::string;
using std::vector;
using ReferenceManager::SafePointer;
using ReferenceManager::SectionKey;
using ReferenceManager::SectionOffsetKey;
using ReferenceManager::SectionIndexKey;
 
const int AOutTextSectionReader::OFFSET_TO_IMMEDIATE_VALUE = 4;
AOutTextSectionReader AOutTextSectionReader::proto_;
 
 
/**
 * Constructor.
 *
 * Registers itself to SectionReader.
 */
AOutTextSectionReader::AOutTextSectionReader() : AOutSectionReader() {
    SectionReader::registerSectionReader(this);
}
 
/**
 * Destructor.
 */
AOutTextSectionReader::~AOutTextSectionReader() {
}
 
/**
 * Returns section type which reader can read.
 *
 * @return The type of the section that reader can read.
 */
Section::SectionType
AOutTextSectionReader::type() const {
    return Section::ST_CODE;
}
 
/**
 * Reads all Moves from stream and stores them in to Section.
 *
 * One move consists of 4 fields: guard (Byte), immediate (Byte),
 * destination index (HalfWord), and source index (Word). If immediate
 * is 1 then the source field of the move contains an immediate value.
 *
 * @param stream Stream to be read from.
 * @param section Pointer to section in which information is stored.
 * @exception UnreachableStream If reading of section fails.
 * @exception KeyAlreadyExists Key was in use when trying to register object.
 * @exception EndOfFile If end of file were reached while it shouldn't.
 * @exception OutOfRange Some of read values were out of range.
 * @exception WrongSubclass Some class couldn't do what it was asked for.
 * @exception UnexpectedValue If there was unexpected value when reading.
 */
void
AOutTextSectionReader::readData(BinaryStream& stream, Section* section) const {
    AOutReader* aOutReader = dynamic_cast<AOutReader*>(parent());
 
    FileOffset offset = stream.readPosition();
    Word length = aOutReader->header().sectionSizeText();
 
    while (stream.readPosition() < offset + length) {
 
        SectionOffset sectionOffset = stream.readPosition() - offset;
 
        // we must first discover whether instruction is immediate or not
        Byte guard = stream.readByte();
        Byte imm = stream.readByte();
 
        MoveElement* move = new MoveElement();
        ImmediateElement* immediate = NULL;
 
        // guard register is the only boolean register of a.out binaries
        assert((guard == 0) || (guard == '!') || (guard == '?'));
        move->setGuardUnit(ResourceElement::BOOL_RF);
        move->setGuardIndex(0);
        move->setGuardType(MoveElement::MF_RF);
        move->setGuarded(guard != 0);
        move->setGuardInverted(guard == '!');
 
        // always use universal bus
        move->setBus(ResourceElement::UNIVERSAL_BUS);
 
        if (imm == 1) {
            immediate = new ImmediateElement();
            initializeImmediateMove(stream, move, immediate);
            immediate->setBegin(true);
            section->addElement(immediate);
            section->addElement(move);
 
            // set reference pointing immediate, since move is never
            // referenced
            setReference(immediate, sectionOffset, AOutReader::ST_TEXT);
 
        } else {
            initializeMove(stream, move);
            move->setBegin(true);
            section->addElement(move);
            setReference(move, sectionOffset, AOutReader::ST_TEXT);
        }
    }
}
 
/**
 * The attributes of move that has immediate in its source field are
 * initialized.
 *
 * Immediate value of a move is modeled as a separate object.
 *
 * @param stream Stream to be read from.
 * @param move Move to be initialized
 * @param immediate Immediate to be initialized.
 * @exception OutOfRange If destination register index is too large.
 * @exception UnreachableStream If there occurs problems with stream.
 */
void
AOutTextSectionReader::initializeImmediateMove(
    BinaryStream& stream, MoveElement* move,
    ImmediateElement* immediate) const {
    move->setSourceType(MoveElement::MF_IMM);
 
    // mark every immediate to be inline encoded
    immediate->setDestinationUnit(ResourceElement::INLINE_IMM);
    immediate->setDestinationIndex(0);
 
    // mark move source to match immediate
    move->setSourceUnit(ResourceElement::INLINE_IMM);
    move->setSourceIndex(0);
 
    HalfWord dest = stream.readHalfWord();
    updateMoveDestination(move, dest);
 
    immediate->setWord(stream.readWord());
}
 
/**
 * Initializes an 'ordinary' Move.
 *
 * @param stream Stream to be read from.
 * @param move Move to be initialized.
 * @exception OutOfRange If destination or source register index is too big.
 * @exception UnreachableStream If there occurs problems with stream.
 */
void
AOutTextSectionReader::initializeMove(
    BinaryStream& stream, MoveElement* move) const {
    HalfWord dest = stream.readHalfWord();
    updateMoveDestination(move, dest);
 
    Word src = stream.readWord();
    updateMoveSource(move, src);
}
 
/**
 * Convert an a.out register index into a TPEF register index.
 *
 * Service helper method.  The callers are responsible for ensuring that the
 * given register index is within the allowed range.
 *
 * @param reg A.out index of the register.
 * @return The TPEF index of the same register.
 */
Word
AOutTextSectionReader::convertAOutIndexToTPEF(Word reg) const {
 
    // NOTE: This implementation depends on AOutSymbolSectionReader
    //       implementation  (Where resource section is read).
 
    // offset to first index of given register class
    int regOffset = 0;
 
    // int reg
    if (reg < AOutReader::FIRST_FP_REGISTER) {
        regOffset = AOutReader::FIRST_INT_REGISTER;
 
    // fp reg
    } else if (reg < AOutReader::FIRST_BOOL_REGISTER) {
        regOffset = AOutReader::FIRST_FP_REGISTER;
 
    // bool register
    } else if (reg < AOutReader::FIRST_FU_REGISTER) {
        regOffset = AOutReader::FIRST_BOOL_REGISTER;
 
    // fu or special register
    } else {
        regOffset = 0;
    }
 
    return reg - regOffset;
}
 
/**
 * Convert an a.out register index to a TPEF register index and update the
 * destination of the given move to reflect the given register index.
 *
 * Possible values of move destination field are indices of: integer
 * registers, floating point registers, Boolean registers, or function unit
 * registers. The type of the move destination is also set.
 *
 * @param move The Move to be updated.
 * @param dest Index of the destination register.
 * @exception OutOfRange If destination index is too large.
 */
void
AOutTextSectionReader::updateMoveDestination(
    MoveElement* move, const HalfWord dest) const {
    if (dest < AOutReader::FIRST_FP_REGISTER) {
        move->setDestinationUnit(ResourceElement::INT_RF);
        move->setDestinationType(MoveElement::MF_RF);
 
    } else if (dest < AOutReader::FIRST_BOOL_REGISTER) {
        move->setDestinationUnit(ResourceElement::FP_RF);
        move->setDestinationType(MoveElement::MF_RF);
 
    } else if (dest < AOutReader::FIRST_FU_REGISTER) {
        move->setDestinationUnit(ResourceElement::BOOL_RF);
        move->setDestinationType(MoveElement::MF_RF);
 
    } else {
        // for special registers move type fields is same that for fu
        move->setDestinationUnit(ResourceElement::UNIVERSAL_FU);
        move->setDestinationType(MoveElement::MF_UNIT);
    }
 
    move->setDestinationIndex(convertAOutIndexToTPEF(dest));
}
 
/**
 * Convert an a.out register index to a TPEF register index and update the
 * source of the given move to reflect the given register index.
 *
 * Possible values of move source field are indices of: integer registers,
 * floating point registers, Boolean registers, or function unit
 * registers. The type of the move source is also set.
 *
 * @param move The Move to be updated.
 * @param src Index of the source register.
 * @exception OutOfRange If source index is too large.
 */
void
AOutTextSectionReader::updateMoveSource(
    MoveElement* move, const Word src) const {
    if (src < AOutReader::FIRST_FP_REGISTER) {
        move->setSourceUnit(ResourceElement::INT_RF);
        move->setSourceType(MoveElement::MF_RF);
 
    } else if (src < AOutReader::FIRST_BOOL_REGISTER) {
        move->setSourceUnit(ResourceElement::FP_RF);
        move->setSourceType(MoveElement::MF_RF);
 
    } else if (src < AOutReader::FIRST_FU_REGISTER) {
        move->setSourceUnit(ResourceElement::BOOL_RF);
        move->setSourceType(MoveElement::MF_RF);
 
    } else {
        // for special registers move type fields is same that for fu
        move->setSourceUnit(ResourceElement::UNIVERSAL_FU);
        move->setSourceType(MoveElement::MF_UNIT);
    }
 
    move->setSourceIndex(convertAOutIndexToTPEF(src));
}
 
/**
 * Sets references to ReferenceManager to enable referencing if
 * it's needed later.
 *
 * @param elem Element to be registered to ReferenceManager.
 * @param sectionOffset The offset of the element in the section.
 * @param sectionID Identification code of the referenced section.
 * @exception KeyAlreadyExists If registration fails because of existing key.
 */
void
AOutTextSectionReader::setReference(
    InstructionElement* elem, SectionOffset sectionOffset,
    SectionId sectionID) const {
    SectionOffsetKey offKey = SectionOffsetKey(sectionID, sectionOffset);
    SafePointer::addObjectReference(offKey, elem);
}
}