scfx_mant.hh

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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 __SYSTEMC_EXT_DT_FX_SCFX_MANT_HH__
#define __SYSTEMC_EXT_DT_FX_SCFX_MANT_HH__

#include "../../utils/endian.hh"
#include "../../utils/functions.hh"
#include "scfx_ieee.hh"
#include "scfx_utils.hh"

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 : scfx_mant
//
//  Mantissa class.
// ----------------------------------------------------------------------------

class 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_BOOST_BIG_ENDIAN )
    return alloc_word(size) + (size - 1);
#elif defined(SC_BOOST_LITTLE_ENDIAN)
    return alloc_word(size);
#endif
}

inline void
scfx_mant::free(word *mant, std::size_t size)
{
#if defined(SC_BOOST_BIG_ENDIAN)
    free_word(mant - (size - 1), size);
#elif defined(SC_BOOST_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_BOOST_BIG_ENDIAN)
    return m_array[-i];
#elif defined(SC_BOOST_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_BOOST_BIG_ENDIAN)
    return m_array[-i];
#elif defined(SC_BOOST_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_BOOST_BIG_ENDIAN)
                        p[-i] = m_array[-i];
#elif defined(SC_BOOST_LITTLE_ENDIAN)
                        p[i] = m_array[i];
#endif
                    } else {
#if defined(SC_BOOST_BIG_ENDIAN)
                        p[-i] = 0;
#elif defined(SC_BOOST_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_BOOST_BIG_ENDIAN)
                        p[-size + 1 + i] = m_array[-m_size + 1 + i];
#elif defined(SC_BOOST_LITTLE_ENDIAN)
                        p[size - 1 - i] = m_array[m_size - 1 - i];
#endif
                    } else {
#if defined(SC_BOOST_BIG_ENDIAN)
                        p[-size + 1 + i] = 0;
#elif defined(SC_BOOST_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_BOOST_BIG_ENDIAN)
    return reinterpret_cast<half_word *>(m_array)[-i];
#elif defined(SC_BOOST_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_BOOST_BIG_ENDIAN)
    return reinterpret_cast<half_word *>(m_array)[-i];
#elif defined(SC_BOOST_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_BOOST_BIG_ENDIAN)
    return reinterpret_cast<half_word *>(m_array - i) + 1;
#elif defined(SC_BOOST_LITTLE_ENDIAN)
    return reinterpret_cast<half_word *>(m_array + i);
#endif
}

// ----------------------------------------------------------------------------
//  one's complement of a mantissa
// ----------------------------------------------------------------------------

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

// ----------------------------------------------------------------------------
//  increment mantissa
// ----------------------------------------------------------------------------

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

// ----------------------------------------------------------------------------
//  CLASS : scfx_mant_ref
//
//  Mantissa reference class.
// ----------------------------------------------------------------------------

class 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 // __SYSTEMC_EXT_DT_FX_SCFX_MANT_HH__