DataSection.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 DataSection.cc
 *
 * Non-inline definitions of DataSection class.
 *
 * @author Mikael Lepistö 2003 (tmlepist-no.spam-cs.tut.fi)
 * @author Pekka Jääskeläinen 2006 (pjaaskel-no.spam-cs.tut.fi)
 *
 * @note rating: yellow
 */
 
#include <cmath>
 
#include "DataSection.hh"
#include "Application.hh"
#include "Swapper.hh"
#include "MathTools.hh"
 
namespace TPEF {
 
DataSection DataSection::proto_(true);
 
/**
 * Constructor.
 *
 * @param init true if registeration is wanted
 */
DataSection::DataSection(bool init) : UDataSection(false) {
 
    if (init) {
        Section::registerSection(this);
    }
 
    unsetFlagVLen();
    unsetFlagNoBits();
}
 
/**
 * Destructor.
 */
DataSection::~DataSection() {
}
 
/**
 * Returns section's type.
 *
 * @return Type of section.
 */
Section::SectionType
DataSection::type() const {
    return ST_DATA;
}
 
/**
 * Sets value of one byte of data section.
 *
 * NOTE: Byte here is tpef file byte. (8bits).
 *
 * @param offset Offset where to write the byte.
 * @param aByte Value to write.
 */
void
DataSection::setByte(Word offset, Byte aByte) {
    if (offset >= data_.size()) {
        abortWithError(
            "Can't set byte " +
            Conversion::toString(static_cast<int>(aByte)) +
            " to offset: " + Conversion::toString(offset) +
            "\t data section size: " + Conversion::toString(data_.size()));
    }
    data_[offset] = aByte;
}
 
/**
 * Creates an instance of DataSection.
 *
 * @return Newly created section.
 */
Section*
DataSection::clone() const {
    return new DataSection(false);
}
 
/**
 * Returns byte from chunk's offset.
 *
 * @param chunk Chunk containing offset of data.
 * @return Byte from chunk offset.
 */
Byte
DataSection::byte(const Chunk* chunk) const {
    return data_[chunk->offset()];
}
 
/**
 * Returns one MAU from section by gived MAU index.
 *
 * @param index Index of MAU to return.
 * @return One MAU of data section.
 */
MinimumAddressableUnit
DataSection::MAU(Word index) const {
 
    int byteOffset = MAUsToBytes(index);
    int mauInBytes = MAUsToBytes(1);
 
    MinimumAddressableUnit retVal = 0;
    
    // read all the bytes to retval
    for(int i = 0; i < mauInBytes; i++) {
        retVal = (retVal << BYTE_BITWIDTH) | 
            static_cast<MinimumAddressableUnit>(byte(byteOffset+i));
    }
    
    return retVal;
}
 
/**
 * Adds MAU to the end of section.
 *
 * @param aMAU MAU that will be copied into the section.
 * @exception OutOfRange If the given value could not fit to the bit count
 * defined by the address space's MAU width (when interpreted as unsigned or
 * signed integer).
 */
void
DataSection::addMAU(MinimumAddressableUnit aMAU) {
    int mauBits = aSpace()->MAU();
    
    if (MathTools::requiredBits(aMAU) > mauBits) {
        if (MathTools::requiredBitsSigned(aMAU) > mauBits) {
            throw OutOfRange(
                __FILE__, __LINE__, __func__,
                "The given value does not fit to the MAU of address space.");
        }
    }
 
    // how many bits are left to last byte
    int modulo = mauBits % BYTE_BITWIDTH;
    
    // write first bits
    if (modulo != 0) {
        mauBits -= modulo;            
        addByte(static_cast<Byte>(aMAU >> mauBits));
    }
    
    // move shifting to right for the next MAU
    mauBits -= BYTE_BITWIDTH;
    
    // write the rest
    for (; mauBits >= 0; 
         mauBits = mauBits - BYTE_BITWIDTH) {                
        
        addByte(static_cast<Byte>(aMAU >> mauBits));
    }
}
 
/**
 * Returns byte from byte offset.
 *
 * @param offset Offset of data.
 * @return Byte from offset.
 */
Byte
DataSection::byte(Word offset) const {
    return data_[offset];
}
 
/**
 * Adds byte of data into section.
 *
 * Method copies data that is given in parameter.
 *
 * @param aByte Byte that will be copied into the section.
 */
void
DataSection::addByte(Byte aByte) {
    data_.push_back(aByte);
}
 
/**
 * Returns the size of the data section in bytes.
 *
 * @return Length of data in bytes.
 */
Word
DataSection::length() const {
    return data_.size();
}
 
/**
 * Tries to set data length. 
 
 * Can be used only for making section bigger. Asserts if method is 
 * tried to use for making section smaller.
 *
 * Initializes data with zeros.
 *
 * @param length Length to which section is expanded.
 */
void
DataSection::setDataLength(Word aLength) {
    assert(length() <= aLength);
    while (length() < aLength) {
        addByte(0);
    }
}
 
/**
 * Writes unsigned value to data section.
 *
 * Value is aligned to field as normal big endian value
 * least significant bit is stored to last bit of last MAU.
 *
 * If we call writeValue(0, 4, 3) and MAU is 2bit
 * start of data section will be 00 00 00 11.
 *
 * However the MAUs are stored in data section like this:
 * 00000000|000000000|00000000|00000011 (one MAU per byte)
 *    MAU1 |   MAU2  |  MAU3  | MAU4
 *
 * @param index MAU offset to section where to we write value.
 * @param numOfMAUs Number of MAUs that we use for storing value.
 * @param value Value to write.
 */
void
DataSection::writeValue(Word index, Word numOfMAUs, unsigned long value) {
 
    int mauInBytes = MAUsToBytes(1);    
    
    MinimumAddressableUnit mauMask = 
        static_cast<unsigned int>(-1) >> 
        (sizeof(mauMask)*BYTE_BITWIDTH - aSpace()->MAU());
    
    int shiftCount = 0;
 
    // start writing from end of area..
    for (int i = numOfMAUs - 1; i >= 0; i--) {
        int byteOffset = MAUsToBytes(index + i);
        
        MinimumAddressableUnit currentMAU = 0;
 
        if (shiftCount < static_cast<int>(sizeof(value)*BYTE_BITWIDTH)) {
            // I tried math tools... system tests went broken :(
            // ssooo... if it's not broken.... 
            currentMAU = (value >> shiftCount) & mauMask;
        }
        
        shiftCount += aSpace()->MAU();
        
        // write current MAU :)
        for (int j = mauInBytes-1; j >= 0; j--) {
            Byte currentByte = static_cast<Byte>(currentMAU);
            setByte(byteOffset + j, currentByte);
            currentMAU = currentMAU >> BYTE_BITWIDTH;
        }
    }
}
 
/**
 * Writes signed value to data section.
 *
 * For example, when we call writeValue(0, 4, -3) and MAU is 2bit
 * start of data section will be 11 11 11 01.
 * 
 * MAUs are stored in data section like this:
 * 00000011 000000011 00000011 00000001 (one MAU per byte)
 *
 * If we call writeValue(0, 4, -3) and MAU is 10bit
 * start of data section will be 1111111111 1111111111 1111111111 1111111101.
 *
 * However the MAUs are stored in data section like this:
 *
 * 00000011 11111111|00000011 11111111|00000011 11111111|00000011 11111101|
 *       MAU1       |      MAU2       |      MAU3       |      MAU4       |
 *
 * @param index MAU offset to section where to we write value.
 * @param numOfMAUs Number of MAUs that we use for storing value.
 * @param value Value to write.
 */
void
DataSection::writeValue(Word index, Word numOfMAUs, signed long value) { 
 
    int mauInBytes = MAUsToBytes(1);    
    
    MinimumAddressableUnit mauMask = 
        static_cast<unsigned int>(-1) >> 
        (sizeof(mauMask)*BYTE_BITWIDTH - aSpace()->MAU());
    
    int shiftCount = 0;
 
    // start writing from end of area..
    for (int i = numOfMAUs - 1; i >= 0; i--) {
        int byteOffset = MAUsToBytes(index + i);
        
        MinimumAddressableUnit currentMAU = 
            static_cast<MinimumAddressableUnit>(~0);
        
        if (shiftCount < static_cast<int>(sizeof(value)*BYTE_BITWIDTH)) {
            // I tried math tools... system tests went broken :(
            // ssooo... if it's not broken.... 
            currentMAU = (value >> shiftCount) & mauMask;
            shiftCount += aSpace()->MAU();
        }
        
        // write current MAU :)
        for (int j = mauInBytes-1; j >= 0; j--) {
            Byte currentByte = static_cast<Byte>(currentMAU);
            setByte(byteOffset + j,currentByte);
            currentMAU = currentMAU >> BYTE_BITWIDTH;
        }
    }
}
 
}