RegisterState.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 RegisterState.cc
 *
 * Definition of RegisterState class.
 *
 * @author Jussi Nykänen 2004 (nykanen-no.spam-cs.tut.fi)
 * @author Pekka Jääskeläinen 2005 (pjaaskel-no.spam-cs.tut.fi)
 * @note rating: red
 */
 
#include "RegisterState.hh"
#include "Application.hh"
 
using std::string;
 
//////////////////////////////////////////////////////////////////////////////
// RegisterState
//////////////////////////////////////////////////////////////////////////////
 
 
/**
 * Constructor.
 *
 * @param width The width of the register.
 * @param constantZero Tells whether the register is constant zero
 */
RegisterState::RegisterState(int width, bool constantZero) : 
    StateData(), value_(*(new SimValue(width))), shared_(false),
    constantZero_(constantZero) {
}
 
/**
 * Constructor for RegisterState which shares the actual register storage.
 *
 * @param sharedRegister The register which is shared with this.
 */
RegisterState::RegisterState(SimValue& sharedRegister) : 
    StateData(), value_(sharedRegister), shared_(true),
    constantZero_(false) {
}
 
/**
 * Destructor.
 */
RegisterState::~RegisterState() {
    if (!shared_) {
        delete &value_;
    }
}
 
/**
 * Sets the value for the register.
 *
 * @param value Value to be set.
 */
void
RegisterState::setValue(const SimValue& value) {
    if (!constantZero_) {
        value_ = value;
    } 
}
 
/**
 * Returns the value of the register.
 *
 * @return The value of the register.
 */
const SimValue&
RegisterState::value() const {
    return value_;
}
 
//////////////////////////////////////////////////////////////////////////////
// NullRegisterState
//////////////////////////////////////////////////////////////////////////////
 
NullRegisterState* NullRegisterState::instance_ = NULL;
 
/**
 * Returns instance of NullRegisterState.
 *
 * @return The instance of NullRegisterState.
 */
NullRegisterState&
NullRegisterState::instance() {
    if (instance_ == NULL) {
        instance_ = new NullRegisterState();
    }
    return *instance_;
}
 
/**
 * Constructor.
 */
NullRegisterState::NullRegisterState() : RegisterState(0) {
}
 
/**
 * Destructor.
 */
NullRegisterState::~NullRegisterState() {
}
 
/**
 * Aborts the program with error message.
 */
void
NullRegisterState::setValue(const SimValue&) {
    Application::abortWithError("setValue()");
}
 
/**
 * Aborts the program with error message.
 *
 * @return Never returns.
 */
const SimValue&
NullRegisterState::value() const {
    Application::abortWithError("value()");
    return NullSimValue::instance();
}