sc_logic.h

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  source code Copyright (c) 1996-2014 by all Contributors.
  All Rights reserved.

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  set forth in the SystemC Open Source License (the "License");
  You may not use this file except in compliance with such restrictions and
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/*****************************************************************************

  sc_logic.h -- C++ implementation of logic type. Behaves
                pretty much the same way as HDLs except with 4 values.

  Original Author: Stan Y. Liao, Synopsys, Inc.

 *****************************************************************************/

/*****************************************************************************

  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
  changes you are making here.

      Name, Affiliation, Date:
  Description of Modification:

 *****************************************************************************/

// $Log: sc_logic.h,v $
// Revision 1.3  2011/08/07 18:54:19  acg
//  Philipp A. Hartmann: remove friend function declarations that implement
//  code, and clean up how bit and logic operators are defined in general.
//
// Revision 1.2  2011/01/25 20:50:37  acg
//  Andy Goodrich: changes for IEEE 1666 2011.
//
// Revision 1.1.1.1  2006/12/15 20:20:04  acg
// SystemC 2.3
//
// Revision 1.5  2006/12/02 21:00:57  acg
//  Andy Goodrich: fixes for concatenation support.
//
// Revision 1.4  2006/05/08 17:49:59  acg
//   Andy Goodrich: Added David Long's declarations for friend operators,
//   functions, and methods, to keep the Microsoft compiler happy.
//
// Revision 1.3  2006/01/13 18:53:53  acg
// Andy Goodrich: added $Log command so that CVS comments are reproduced in
// the source.
//

#ifndef SC_LOGIC_H
#define SC_LOGIC_H


#include <cstdio>

#include "sysc/utils/sc_iostream.h"
#include "sysc/kernel/sc_macros.h"
#include "sysc/utils/sc_mempool.h"
#include "sysc/datatypes/bit/sc_bit.h"


namespace sc_dt
{

// classes defined in this module
class sc_logic;


// ----------------------------------------------------------------------------
//  ENUM : sc_logic_value_t
//
//  Enumeration of values for sc_logic.
// ----------------------------------------------------------------------------

enum sc_logic_value_t
{
    Log_0 = 0,
    Log_1,
    Log_Z,
    Log_X
};

// ----------------------------------------------------------------------------
//  CLASS : sc_logic
//
//  Four-valued logic type.
// ----------------------------------------------------------------------------

class sc_logic
{
private:

    // support methods

    static void invalid_value( sc_logic_value_t );
    static void invalid_value( char );
    static void invalid_value( int );

    static sc_logic_value_t to_value( sc_logic_value_t v )
        {
            if( v < Log_0 || v > Log_X ) {
                invalid_value( v );
            }
            return v;
        }

    static sc_logic_value_t to_value( bool b )
        { return ( b ? Log_1 : Log_0 ); }

    static sc_logic_value_t to_value( char c )
        {
            sc_logic_value_t v;
            unsigned int index = (int)c;
            if ( index > 127 )
            {
                invalid_value(c);
                v = Log_X;
            }
            else
            {
                v = char_to_logic[index];
                if( v < Log_0 || v > Log_X ) {
                    invalid_value( c );
                }
            }
            return v;
        }

    static sc_logic_value_t to_value( int i )
        {
            if( i < 0 || i > 3 ) {
                invalid_value( i );
            }
            return sc_logic_value_t( i );
        }


    void invalid_01() const;

public:

    // conversion tables

    static const sc_logic_value_t char_to_logic[128];
    static const char logic_to_char[4];
    static const sc_logic_value_t and_table[4][4];
    static const sc_logic_value_t or_table[4][4];
    static const sc_logic_value_t xor_table[4][4];
    static const sc_logic_value_t not_table[4];


    // constructors

    sc_logic()
        : m_val( Log_X )
        {}

    sc_logic( const sc_logic& a )
        : m_val( a.m_val )
        {}

    sc_logic( sc_logic_value_t v )
        : m_val( to_value( v ) )
        {}

    explicit sc_logic( bool a )
        : m_val( to_value( a ) )
        {}

    explicit sc_logic( char a )
        : m_val( to_value( a ) )
        {}

    explicit sc_logic( int a )
        : m_val( to_value( a ) )
        {}

    explicit sc_logic( const sc_bit& a )
        : m_val( to_value( a.to_bool() ) )
        {}


    // destructor

    ~sc_logic()
        {}


    // (bitwise) assignment operators

#define DEFN_ASN_OP_T(op,tp)                       \
    sc_logic& operator op ( tp v )                 \
        { *this op sc_logic( v ); return *this; }

#define DEFN_ASN_OP(op)                            \
    DEFN_ASN_OP_T(op, sc_logic_value_t)            \
    DEFN_ASN_OP_T(op, bool)                        \
    DEFN_ASN_OP_T(op, char)                        \
    DEFN_ASN_OP_T(op, int )                        \
    DEFN_ASN_OP_T(op, const sc_bit& )

    sc_logic& operator = ( const sc_logic& a )
        { m_val = a.m_val; return *this; }

    sc_logic& operator &= ( const sc_logic& b )
        { m_val = and_table[m_val][b.m_val]; return *this; }

    sc_logic& operator |= ( const sc_logic& b )
        { m_val = or_table[m_val][b.m_val]; return *this; }

    sc_logic& operator ^= ( const sc_logic& b )
        { m_val = xor_table[m_val][b.m_val]; return *this; }

    DEFN_ASN_OP(=)
    DEFN_ASN_OP(&=)
    DEFN_ASN_OP(|=)
    DEFN_ASN_OP(^=)

#undef DEFN_ASN_OP_T
#undef DEFN_ASN_OP


    // bitwise operators and functions


    friend const sc_logic operator & ( const sc_logic&, const sc_logic& );
    friend const sc_logic operator | ( const sc_logic&, const sc_logic& );
    friend const sc_logic operator ^ ( const sc_logic&, const sc_logic& );

    // relational operators

    friend bool operator == ( const sc_logic&, const sc_logic& );
    friend bool operator != ( const sc_logic&, const sc_logic& );

    // bitwise complement

    const sc_logic operator ~ () const
        { return sc_logic( not_table[m_val] ); }

    sc_logic& b_not()
        { m_val = not_table[m_val]; return *this; }


    // explicit conversions

    sc_logic_value_t value() const
        { return m_val; }


    bool is_01() const
        { return ( (int) m_val == Log_0 || (int) m_val == Log_1 ); }

    bool to_bool() const
        { if( ! is_01() ) { invalid_01(); } return ( (int) m_val != Log_0 ); }

    char to_char() const
        { return logic_to_char[m_val]; }


    // other methods

    void print( ::std::ostream& os = ::std::cout ) const
        { os << to_char(); }

    void scan( ::std::istream& is = ::std::cin );


    // memory (de)allocation

    static void* operator new( std::size_t, void* p ) // placement new
        { return p; }

    static void* operator new( std::size_t sz )
        { return sc_core::sc_mempool::allocate( sz ); }

    static void operator delete( void* p, std::size_t sz )
        { sc_core::sc_mempool::release( p, sz ); }

    static void* operator new [] ( std::size_t sz )
        { return sc_core::sc_mempool::allocate( sz ); }

    static void operator delete [] ( void* p, std::size_t sz )
        { sc_core::sc_mempool::release( p, sz ); }

private:

    sc_logic_value_t m_val;

private:

    // disabled
    explicit sc_logic( const char* );
    sc_logic& operator = ( const char* );
};

// ----------------------------------------------------------------------------

// bitwise operators

inline const sc_logic operator & ( const sc_logic& a, const sc_logic& b )
       { return sc_logic( sc_logic::and_table[a.m_val][b.m_val] ); }

inline const sc_logic operator | ( const sc_logic& a, const sc_logic& b )
       { return sc_logic( sc_logic::or_table[a.m_val][b.m_val] ); }

inline const sc_logic operator ^ ( const sc_logic& a, const sc_logic& b )
       { return sc_logic( sc_logic::xor_table[a.m_val][b.m_val] ); }

#define DEFN_BIN_OP_T(ret,op,tp)                       \
    inline ret operator op ( const sc_logic& a, tp b ) \
        { return ( a op sc_logic( b ) ); }             \
    inline ret operator op ( tp a, const sc_logic& b ) \
        { return ( sc_logic( a ) op b ); }

#define DEFN_BIN_OP(ret,op)                            \
    DEFN_BIN_OP_T(ret,op,sc_logic_value_t)             \
    DEFN_BIN_OP_T(ret,op,bool)                         \
    DEFN_BIN_OP_T(ret,op,char)                         \
    DEFN_BIN_OP_T(ret,op,int)

DEFN_BIN_OP(const sc_logic,&)
DEFN_BIN_OP(const sc_logic,|)
DEFN_BIN_OP(const sc_logic,^)

// relational operators and functions

inline bool operator == ( const sc_logic& a, const sc_logic& b )
       { return ( (int) a.m_val == b.m_val ); }

inline bool operator != ( const sc_logic& a, const sc_logic& b )
       { return ( (int) a.m_val != b.m_val ); }

DEFN_BIN_OP(bool,==)
DEFN_BIN_OP(bool,!=)

#undef DEFN_BIN_OP_T
#undef DEFN_BIN_OP

// ----------------------------------------------------------------------------

inline
::std::ostream&
operator << ( ::std::ostream& os, const sc_logic& a )
{
    a.print( os );
    return os;
}

inline
::std::istream&
operator >> ( ::std::istream& is, sc_logic& a )
{
    a.scan( is );
    return is;
}


extern const sc_logic SC_LOGIC_0;
extern const sc_logic SC_LOGIC_1;
extern const sc_logic SC_LOGIC_Z;
extern const sc_logic SC_LOGIC_X;

// #ifdef SC_DT_DEPRECATED
extern const sc_logic sc_logic_0;
extern const sc_logic sc_logic_1;
extern const sc_logic sc_logic_Z;
extern const sc_logic sc_logic_X;
// #endif

} // namespace sc_dt

#endif