DirectAccessMemory.hh

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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 DirectAccessMemory.hh
 *
 * Declaration of DirectAccessMemory class.
 *
 * @author Pekka Jääskeläinen 2007 (pekka.jaaskelainen-no.spam-tut.fi)
 * @note This file is used in compiled simulation. Keep dependencies *clean*
 * @note rating: red
 */
 
#ifndef TTA_DIRECT_ACCESS_MEMORY_HH
#define TTA_DIRECT_ACCESS_MEMORY_HH
 
#include "Memory.hh"
#include "BaseType.hh"
 
class MemoryContents;
 
/**
 * Class that models an "ideal" memory to which updates are visible
 * immediately.
 *
 * This model is used in compiled simulation. It does not require an
 * advance clock call: all writes to it are visible immediately. Thus,
 * one has to make sure that all reads in the same cycle are executed
 * before writes in order for the reads to read the old values.
 *
 * Note that all range checking is disabled for fastest possible simulation
 * model. In case you are unsure of your simulated input correctness, use
 * the old simulation engine for verification.
 */
class DirectAccessMemory : public Memory {
public:
    DirectAccessMemory(
        ULongWord start,
        ULongWord end,
        Word MAUSize, bool littleEndian);
 
    virtual ~DirectAccessMemory();
 
    void write(ULongWord address, Memory::MAU data) override;
    
    void fastWriteMAU(
        ULongWord address,
        ULongWord data);
    
    void fastWrite2MAUsBE(
        ULongWord address,
        ULongWord data);
    
    void fastWrite4MAUsBE(
        ULongWord address,
        ULongWord data);
 
    void fastWrite2MAUsLE(
        ULongWord address,
        ULongWord data);
    
    void fastWrite4MAUsLE(
        ULongWord address,
        ULongWord data);
 
    Memory::MAU read(ULongWord address) override;
    
    void fastReadMAU(
        ULongWord address,
        ULongWord& data);
    
    void fastRead2MAUsBE(
        ULongWord address,
        ULongWord& data);
    
    void fastRead4MAUsBE(
        ULongWord address,
        ULongWord& data);
 
    void fastRead2MAUsLE(
        ULongWord address,
        ULongWord& data);
    
    void fastRead4MAUsLE(
        ULongWord address,
        ULongWord& data);
 
    virtual void advanceClock() {}
    virtual void reset() {}
    virtual void fillWithZeros();
 
    void writeBE(ULongWord address, int count, ULongWord data) override;
 
 
    using Memory::write;
    using Memory::read;
 
private:
    /// Copying not allowed.
    DirectAccessMemory(const DirectAccessMemory&);
    /// Assignment not allowed.
    DirectAccessMemory& operator=(const DirectAccessMemory&);
 
    /// Starting point of the address space.
    Word start_;
    /// End point of the address space.
    Word end_;
    /// Size of the minimum adressable unit.
    Word MAUSize_;
    /// precalculated MAUSize_ * 3
    Word MAUSize3_;
    /// precalculated MAUSize_ * 2
    Word MAUSize2_;    
    /// Size of the natural word as MAUs.
    Word wordSize_;
    /// Mask bit pattern for unpacking IntWord to MAUs.
    Word mask_;
    /// Contains MAUs of the memory model, that is, the actual data of the
    /// memory.
    MemoryContents* data_;
};
 
#endif