scfx_mant.h

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

  scfx_mant.h - 

  Original Author: Robert Graulich, Synopsys, Inc.
                   Martin Janssen,  Synopsys, Inc.

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

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  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
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// $Log: scfx_mant.h,v $
// Revision 1.2  2011/08/24 22:05:43  acg
//  Torsten Maehne: initialization changes to remove warnings.
//
// Revision 1.1.1.1  2006/12/15 20:20:04  acg
// SystemC 2.3
//
// Revision 1.3  2006/01/13 18:53:58  acg
// Andy Goodrich: added $Log command so that CVS comments are reproduced in
// the source.
//

#ifndef SCFX_MANT_H
#define SCFX_MANT_H


#include "sysc/datatypes/fx/scfx_ieee.h"
#include "sysc/datatypes/fx/scfx_utils.h"
#include "sysc/kernel/sc_macros.h"


namespace sc_dt
{

// classes defined in this module
class scfx_mant;
class scfx_mant_ref;


typedef unsigned int  word;       // Using int because of 64-bit machines.
typedef unsigned short half_word;


class SC_API scfx_mant
{

    word* m_array;
    int   m_size;

public:

    explicit scfx_mant( std::size_t );
             scfx_mant( const scfx_mant& );

    scfx_mant& operator = ( const scfx_mant& );

    ~scfx_mant();

    void clear();

    void resize_to( int, int = 0 );

    int size() const;

    word  operator [] ( int ) const;
    word& operator [] ( int );

    half_word  half_at( int ) const;
    half_word& half_at( int );

    half_word* half_addr( int = 0 ) const;

private:

    static word* alloc( std::size_t );
    static void free( word*, std::size_t );

    static word* alloc_word( std::size_t size );
    static void free_word( word* array, std::size_t size );

};


// IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

inline
int
scfx_mant::size() const
{
    return m_size;
}


inline
word*
scfx_mant::alloc( std::size_t size )
{
#if defined( SC_BIG_ENDIAN )
    return alloc_word( size ) + ( size - 1 );
#elif defined( SC_LITTLE_ENDIAN )
    return alloc_word( size );
#endif
}

inline
void
scfx_mant::free( word* mant, std::size_t size )
{
#if defined( SC_BIG_ENDIAN )
    free_word( mant - ( size - 1 ), size );
#elif defined( SC_LITTLE_ENDIAN )
    free_word( mant, size );
#endif
}

inline
word
scfx_mant::operator[]( int i ) const
{
    SC_ASSERT_( i >= 0 && i < m_size, "mantissa index out of range" );
#if defined( SC_BIG_ENDIAN )
    return m_array[-i];
#elif defined( SC_LITTLE_ENDIAN )
    return m_array[i];
#endif
}

inline
word&
scfx_mant::operator[]( int i )
{
    SC_ASSERT_( i >= 0 && i < m_size, "mantissa index out of range" );
#if defined( SC_BIG_ENDIAN )
    return m_array[-i];
#elif defined( SC_LITTLE_ENDIAN )
    return m_array[i];
#endif
}

inline
scfx_mant::scfx_mant( std::size_t size_ )
: m_array(0), m_size(size_)
{
    m_array = alloc( size_ );
}

inline
scfx_mant::scfx_mant( const scfx_mant& rhs )
: m_array(0), m_size(rhs.m_size)
{
    m_array = alloc( m_size );
    for( int i = 0; i < m_size; i ++ )
    {
        (*this)[i] = rhs[i];
    }
}

inline
scfx_mant&
scfx_mant::operator = ( const scfx_mant& rhs )
{
    if( &rhs != this )
    {
        if( m_size != rhs.m_size )
        {
            free( m_array, m_size );
            m_array = alloc( m_size = rhs.m_size );
        }

        for( int i = 0; i < m_size; i ++ )
        {
            (*this)[i] = rhs[i];
        }
    }
    return *this;
}

inline
scfx_mant::~scfx_mant()
{
    if( m_array != 0 )
    {
        free( m_array, m_size );
    }
}

inline
void
scfx_mant::clear()
{
    for( int i = 0; i < m_size; i ++ )
    {
        (*this)[i] = 0;
    }
}

inline
void
scfx_mant::resize_to( int size, int restore )
{
    if( size == m_size )
    {
        return;
    }

    if( ! m_array )
    {
        m_array = alloc( m_size = size );
    }
    else
    {
        word* p = alloc( size );

        if( restore )
        {
            int end = sc_min( size, m_size );
            if( restore == 1 )          // msb resized -> align at 0
            {
                for( int i = 0; i < size; i ++ )
                {
                    if( i < end )
                    {
#if defined( SC_BIG_ENDIAN )
                        p[-i] = m_array[-i];
#elif defined( SC_LITTLE_ENDIAN )
                        p[i] = m_array[i];
#endif
                    }
                    else
                    {
#if defined( SC_BIG_ENDIAN )
                        p[-i] = 0;
#elif defined( SC_LITTLE_ENDIAN )
                        p[i] = 0;
#endif
                    }
                }
            }
            else                        // lsb resized -> align at size-1
            {
                for( int i = 0; i < size; i ++ )
                {
                    if( i < end )
                    {
#if defined( SC_BIG_ENDIAN )
                        p[-size+1+i] = m_array[-m_size+1+i];
#elif defined( SC_LITTLE_ENDIAN )
                        p[size-1-i] = m_array[m_size-1-i];
#endif
                    }
                    else
                    {
#if defined( SC_BIG_ENDIAN )
                        p[-size+1+i] = 0;
#elif defined( SC_LITTLE_ENDIAN )
                        p[size-1-i] = 0;
#endif
                    }
                }
            }
        }

        free( m_array, m_size );
        m_array = p;
        m_size = size;
    }
}

inline
half_word
scfx_mant::half_at( int i ) const
{
    SC_ASSERT_( ( i >> 1 ) >= 0 && ( i >> 1 ) < m_size,
                "mantissa index out of range" );
#if defined( SC_BIG_ENDIAN )
    return reinterpret_cast<half_word*>( m_array )[-i];
#elif defined( SC_LITTLE_ENDIAN )
    return reinterpret_cast<half_word*>( m_array )[i];
#endif
}

inline
half_word&
scfx_mant::half_at( int i )
{
    SC_ASSERT_( ( i >> 1 ) >= 0 && ( i >> 1 ) < m_size,
                "mantissa index out of range" );
#if defined( SC_BIG_ENDIAN )
    return reinterpret_cast<half_word*>( m_array )[-i];
#elif defined( SC_LITTLE_ENDIAN )
    return reinterpret_cast<half_word*>( m_array )[i];
#endif
}

inline
half_word*
scfx_mant::half_addr( int i ) const
{
    SC_ASSERT_( i >= 0 && i < m_size, "mantissa index out of range" );
#if defined( SC_BIG_ENDIAN )
    return reinterpret_cast<half_word*>( m_array - i ) + 1;
#elif defined( SC_LITTLE_ENDIAN )
    return reinterpret_cast<half_word*>( m_array + i );
#endif
}


inline
void
complement( scfx_mant& target, const scfx_mant& source, int size )
{
    for( int i = 0; i < size; i ++ )
    {
        target[i] = ~source[i];
    }
}


inline
void
inc( scfx_mant& mant )
{
    for( int i = 0; i < mant.size(); i ++ )
    {
        if( ++ mant[i] )
        {
            break;
        }
    }
}


class SC_API scfx_mant_ref
{

    scfx_mant* m_mant;
    bool       m_not_const;

public:

    scfx_mant_ref();
    scfx_mant_ref( const scfx_mant& );
    scfx_mant_ref( scfx_mant* );

    scfx_mant_ref& operator = ( const scfx_mant& );
    scfx_mant_ref& operator = ( scfx_mant* );

    ~scfx_mant_ref();

    operator scfx_mant&();

    word operator [] ( int );

private:

    void remove_it();

    scfx_mant_ref( const scfx_mant_ref& );
    scfx_mant_ref& operator = ( const scfx_mant_ref& );

    void* operator new( std::size_t sz ) { return ::operator new( sz ); }

};


// IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

inline
void
scfx_mant_ref::remove_it()
{
    if( m_not_const )
    {
        delete m_mant;
    }
}

inline
scfx_mant_ref::scfx_mant_ref()
: m_mant( 0 ), m_not_const( false )
{}

inline
scfx_mant_ref::scfx_mant_ref( const scfx_mant& mant )
: m_mant( const_cast<scfx_mant*>( &mant ) ), m_not_const( false )
{}

inline
scfx_mant_ref::scfx_mant_ref( scfx_mant* mant )
: m_mant( mant ), m_not_const( true )
{}

inline
scfx_mant_ref&
scfx_mant_ref::operator = ( const scfx_mant& mant )
{
    remove_it();

    m_mant = const_cast<scfx_mant*>( &mant );
    m_not_const = false;

    return *this;
}

inline
scfx_mant_ref&
scfx_mant_ref::operator = ( scfx_mant* mant )
{
    remove_it();

    m_mant = mant;
    m_not_const = true;

    return *this;
}

inline
scfx_mant_ref::~scfx_mant_ref()
{
    remove_it();
}

inline
scfx_mant_ref::operator scfx_mant&()
{
    // SC_ASSERT_( m_not_const, "not allowed to modify mant" );
    return *m_mant;
}

inline
word
scfx_mant_ref::operator [] ( int i )
{
    return (*m_mant)[i];
}

} // namespace sc_dt


#endif

// Taf!