scfx_rep.hh

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  scfx_rep.h -

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

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// $Log: scfx_rep.h,v $
// Revision 1.6  2011/08/24 22:05:43  acg
//  Torsten Maehne: initialization changes to remove warnings.
//
// Revision 1.5  2011/07/25 10:20:29  acg
//  Andy Goodrich: check in aftermath of call to automake.
//
// Revision 1.4  2010/12/07 20:09:08  acg
// Andy Goodrich: Philipp Hartmann's constructor disambiguation fix
//
// Revision 1.3  2010/08/03 15:54:52  acg
//  Andy Goodrich: formatting.
//
// Revision 1.2  2010/03/15 18:29:01  acg
//  Andy Goodrich: Moved default argument specifications from friend
//  declarations to the actual function signatures.
//
// Revision 1.1.1.1  2006/12/15 20:20:04  acg
// SystemC 2.3
//
// Revision 1.4  2006/03/13 20:24:27  acg
//  Andy Goodrich: Addition of function declarations, e.g., neg_scfx_rep(),
//  to keep gcc 4.x happy.
//
// 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_REP_HH__
#define __SYSTEMC_EXT_DT_FX_SCFX_REP_HH__

#include <climits>

#include "scfx_mant.hh"
#include "scfx_params.hh"
#include "scfx_string.hh"

namespace sc_dt
{

// classes defined in this module
class scfx_index;
class scfx_rep;

// forward class declarations
class sc_bv_base;
class sc_signed;
class sc_unsigned;

// function declarations
void multiply(scfx_rep &, const scfx_rep &, const scfx_rep &,
              int max_wl=SC_DEFAULT_MAX_WL_);
scfx_rep *neg_scfx_rep(const scfx_rep &);
scfx_rep *mult_scfx_rep(const scfx_rep &, const scfx_rep &,
                        int max_wl=SC_DEFAULT_MAX_WL_);
scfx_rep *div_scfx_rep(const scfx_rep &, const scfx_rep &,
                       int max_wl=SC_DEFAULT_DIV_WL_);
scfx_rep *add_scfx_rep(const scfx_rep &, const scfx_rep &,
                       int max_wl=SC_DEFAULT_MAX_WL_);
scfx_rep *sub_scfx_rep(const scfx_rep &, const scfx_rep &,
                       int max_wl=SC_DEFAULT_MAX_WL_);
scfx_rep *lsh_scfx_rep(const scfx_rep &, int);
scfx_rep *rsh_scfx_rep(const scfx_rep &, int);
int cmp_scfx_rep(const scfx_rep &, const scfx_rep &);

const int min_mant = 4;

const int bits_in_int = sizeof(int) * CHAR_BIT;
const int bits_in_word = sizeof(word) * CHAR_BIT;


// ----------------------------------------------------------------------------
//  CLASS : scfx_index
// ----------------------------------------------------------------------------

class scfx_index
{
  public:
    scfx_index(int wi_, int bi_) : m_wi(wi_), m_bi(bi_) {}

    int wi() const { return m_wi; }
    int bi() const { return m_bi; }

    void wi(int wi_) { m_wi = wi_; }

  private:
    int m_wi;
    int m_bi;
};


// ----------------------------------------------------------------------------
//  CLASS : scfx_rep
//
//  Arbitrary-precision fixed-point implementation class.
// ----------------------------------------------------------------------------

class scfx_rep
{
    enum state
    {
        normal,
        infinity,
        not_a_number
    };

  public:
    // constructors
    scfx_rep();
    explicit scfx_rep(int);
    explicit scfx_rep(unsigned int);
    explicit scfx_rep(long);
    explicit scfx_rep(unsigned long);
    explicit scfx_rep(double);
    explicit scfx_rep(const char *);
    explicit scfx_rep(int64);
    explicit scfx_rep(uint64);
    explicit scfx_rep(const sc_signed &);
    explicit scfx_rep(const sc_unsigned &);

    // copy constructor
    scfx_rep(const scfx_rep &);

    // destructor
    ~scfx_rep();

    void *operator new (std::size_t);
    void operator delete (void *, std::size_t);

    void from_string(const char *, int);

    double to_double() const;
    uint64 to_uint64() const;

    const char *to_string(sc_numrep, int, sc_fmt,
                          const scfx_params * =0) const;

    // assignment operator
    void operator = (const scfx_rep &);

    friend void multiply( scfx_rep&, const scfx_rep&, const scfx_rep&, int );

    friend scfx_rep *neg_scfx_rep(const scfx_rep &);
    friend scfx_rep *mult_scfx_rep(const scfx_rep &, const scfx_rep &, int);
    friend scfx_rep *div_scfx_rep(const scfx_rep &, const scfx_rep &, int);
    friend scfx_rep *add_scfx_rep(const scfx_rep &, const scfx_rep &, int);
    friend scfx_rep *sub_scfx_rep(const scfx_rep &, const scfx_rep &, int);
    friend scfx_rep *lsh_scfx_rep(const scfx_rep &, int);
    friend scfx_rep *rsh_scfx_rep(const scfx_rep &, int);

    void lshift(int);
    void rshift(int);

    friend int cmp_scfx_rep(const scfx_rep &, const scfx_rep &);

    void cast(const scfx_params &, bool &, bool &);

    bool is_neg() const;
    bool is_zero() const;
    bool is_nan() const;
    bool is_inf() const;
    bool is_normal() const;

    void set_zero(int=1);
    void set_nan();
    void set_inf(int);

    bool get_bit(int) const;
    bool set(int, const scfx_params &);
    bool clear(int, const scfx_params &);

    bool get_slice(int, int, const scfx_params &, sc_bv_base &) const;
    bool set_slice(int, int, const scfx_params &, const sc_bv_base &);

    void print(::std::ostream &) const;
    void dump(::std::ostream &) const;

    void get_type(int &, int &, sc_enc &) const;

    friend scfx_rep *quantization_scfx_rep(
            const scfx_rep &, const scfx_params &, bool &);
    friend scfx_rep *overflow_scfx_rep(
            const scfx_rep &, const scfx_params &, bool &);

    bool rounding_flag() const;

  private:
    friend void align(const scfx_rep &, const scfx_rep &, int &, int &,
                      scfx_mant_ref &, scfx_mant_ref &);
    friend int compare_msw(const scfx_rep &, const scfx_rep &);
    friend int compare_msw_ff(const scfx_rep &lhs, const scfx_rep &rhs);
    unsigned int divide_by_ten();
    int find_lsw() const;
    int find_msw() const;
    void find_sw();
    void multiply_by_ten();
    void normalize(int);
    scfx_mant *resize(int, int) const;
    void set_bin(int);
    void set_oct(int, int);
    void set_hex(int, int);
    void shift_left(int);
    void shift_right(int);

    const scfx_index calc_indices(int) const;

    void o_extend(const scfx_index &, sc_enc);
    bool o_bit_at(const scfx_index &) const;
    bool o_zero_left(const scfx_index &) const;
    bool o_zero_right(const scfx_index &) const;
    void o_set_low(const scfx_index &, sc_enc);
    void o_set_high(const scfx_index &, const scfx_index &, sc_enc, int=1);
    void o_set(const scfx_index &, const scfx_index &, sc_enc, bool);
    void o_invert(const scfx_index &);
    bool q_bit(const scfx_index &) const;
    void q_clear(const scfx_index &);
    void q_incr(const scfx_index &);
    bool q_odd(const scfx_index &) const;
    bool q_zero(const scfx_index &) const;

    void resize_to(int, int=0);
    int  size() const;
    void toggle_tc();

    friend void print_dec(scfx_string &, const scfx_rep &, int, sc_fmt);
    friend void print_other(scfx_string &, const scfx_rep &, sc_numrep, int,
                            sc_fmt, const scfx_params *);

    void quantization(const scfx_params &, bool &);
    void overflow(const scfx_params &, bool &);

    friend int compare_abs(const scfx_rep &, const scfx_rep &);

    void round(int);

  private:
    scfx_mant m_mant; // mantissa (bits of the value).
    int m_wp; // index of highest order word in value.
    int m_sign; // sign of value.
    state m_state; // value state, e.g., normal, inf, etc.
    int m_msw; // index of most significant non-zero word.
    int m_lsw; // index of least significant non-zero word.
    bool m_r_flag; // true if rounding occurred.
};


// IIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIIII

inline void
scfx_rep::set_zero(int sign)
{
    m_mant.clear();
    m_wp = m_msw = m_lsw = 0;
    m_sign = sign;
    m_state = normal;
}

inline void
scfx_rep::set_nan()
{
    m_mant.resize_to(min_mant);
    m_state = not_a_number;
}

inline void
scfx_rep::set_inf(int sign)
{
    m_mant.resize_to(min_mant);
    m_state = infinity;
    m_sign = sign;
}

// constructors
inline scfx_rep::scfx_rep(const char *s) :
    m_mant(min_mant), m_wp(2), m_sign(1), m_state(normal),
    m_msw(0), m_lsw(0), m_r_flag(false)
{
    from_string(s, SC_DEFAULT_CTE_WL_);
}

// destructor
inline scfx_rep::~scfx_rep() {}

// assignment operator
inline void
scfx_rep::operator = (const scfx_rep &f)
{
    if (&f != this) {
        m_mant = f.m_mant;
        m_wp = f.m_wp;
        m_sign = f.m_sign;
        m_state = f.m_state;
        m_msw = f.m_msw;
        m_lsw = f.m_lsw;
        round(SC_DEFAULT_MAX_WL_);
    }
}

inline scfx_rep *
neg_scfx_rep(const scfx_rep &a)
{
    scfx_rep &c = *new scfx_rep(a);
    c.m_sign = - c.m_sign;
    return &c;
}

inline scfx_rep *
mult_scfx_rep(const scfx_rep &a, const scfx_rep &b, int max_wl)
{
    scfx_rep &c = *new scfx_rep;
    sc_dt::multiply(c, a, b, max_wl);
    return &c;
}

inline scfx_rep *
lsh_scfx_rep(const scfx_rep &a, int b)
{
    scfx_rep &c = *new scfx_rep(a);
    c.lshift(b);
    return &c;
}

inline scfx_rep *
rsh_scfx_rep(const scfx_rep &a, int b)
{
    scfx_rep &c = *new scfx_rep(a);
    c.rshift(b);
    return &c;
}

inline int scfx_rep::size() const { return m_mant.size(); }

inline bool scfx_rep::is_neg() const { return (m_sign == -1); }

inline bool
scfx_rep::is_zero() const
{
    if (m_state != normal)
        return false;

    for (int i = 0; i < size(); i++) {
        if (m_mant[i])
            return false;
    }

    return true;
}

inline bool scfx_rep::is_nan() const { return (m_state == not_a_number); }

inline bool scfx_rep::is_inf() const { return (m_state == infinity); }

inline bool scfx_rep::is_normal() const { return (m_state == normal); }

inline scfx_rep *
quantization_scfx_rep(const scfx_rep &a, const scfx_params &params,
                      bool &q_flag)
{
    scfx_rep &c = *new scfx_rep(a);
    c.quantization(params, q_flag);
    return &c;
}

inline scfx_rep *
overflow_scfx_rep(const scfx_rep &a, const scfx_params &params, bool &o_flag)
{
    scfx_rep& c = *new scfx_rep(a);
    c.overflow(params, o_flag);
    return &c;
}

inline bool scfx_rep::rounding_flag() const { return m_r_flag; }

inline void
scfx_rep::resize_to(int new_size, int restore)
{
    if (restore == -1) {
        int size_incr = new_size - size();
        m_wp += size_incr;
        m_msw += size_incr;
        m_lsw += size_incr;
    }
    m_mant.resize_to(new_size, restore);
}

inline const scfx_index
scfx_rep::calc_indices(int n) const
{
    int wi = n / bits_in_word + m_wp;
    int bi = n % bits_in_word;

    if (bi < 0) {
        bi += bits_in_word;
        -- wi;
    }

    return scfx_index(wi, bi);
}

inline void
scfx_rep::o_extend(const scfx_index &x, sc_enc enc)
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    if (enc == SC_US_ || (m_mant[wi] & (((word)1) << bi)) == 0) {
        if (bi != bits_in_word - 1)
            m_mant[wi] &= ~(((word)-1) << (bi + 1));
        for (int i = wi + 1; i < size(); ++i)
            m_mant[i] = 0;
        m_sign = 1;
    } else {
        if (bi != bits_in_word - 1)
            m_mant[wi] |= (((word)-1) << (bi + 1));
        for (int i = wi + 1; i < size(); ++i)
            m_mant[i] = static_cast<word>(-1);
        m_sign = -1;
    }
}

inline bool
scfx_rep::o_bit_at(const scfx_index &x) const
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    return (m_mant[wi] & (((word)1) << bi)) != 0;
}

inline bool
scfx_rep::o_zero_left(const scfx_index &x) const
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    bool zero = true;
    if (bi != bits_in_word - 1)
        zero = (m_mant[wi] & (((word)-1) << (bi + 1))) == 0;
    for (int i = wi + 1; i < size(); ++i)
        zero = zero && m_mant[i] == 0;

    return zero;
}

inline bool
scfx_rep::o_zero_right(const scfx_index &x) const
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    bool zero = (m_mant[wi] & ~(((word)-1) << bi)) == 0;
    for (int i = wi - 1; i >= 0; --i)
        zero = zero && m_mant[i] == 0;

    return zero;
}

inline void
scfx_rep::o_set_low(const scfx_index &x, sc_enc enc)
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    m_mant.clear();

    if (enc == SC_TC_) {
        m_mant[wi] |= (((word)1) << bi);
        m_sign = -1;
    } else {
        m_sign = 1;
    }
}

inline void
scfx_rep::o_set_high(const scfx_index &x, const scfx_index &x2,
                     sc_enc enc, int sign)
{
    int wi = x.wi();
    int bi = x.bi();
    int wi2 = x2.wi();
    int bi2 = x2.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");
    SC_ASSERT_(wi2 >= 0 && wi2 < size(), "word index out of range");

    int i;

    for (i = 0; i < size(); ++i)
        m_mant[i] = static_cast<word>(-1);

    m_mant[wi] &= ~(((word)-1) << bi);
    for (i = wi + 1; i < size(); ++i)
        m_mant[i] = 0;

    m_mant[wi2] &= (((word)-1) << bi2);
    for (i = wi2 - 1; i >= 0; --i)
        m_mant[i] = 0;

    if (enc == SC_TC_) {
        m_sign = sign;
    } else {
        m_mant[wi] |= (((word)1) << bi);
        m_sign = 1;
    }
}

inline void
scfx_rep::o_set(const scfx_index &x, const scfx_index &x3, sc_enc enc,
                bool under)
{
    int wi = x.wi();
    int bi = x.bi();
    int wi3 = x3.wi();
    int bi3 = x3.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");
    SC_ASSERT_(wi3 >= 0 && wi3 < size(), "word index out of range");

    if (bi3 != bits_in_word - 1) {
        if (under)
            m_mant[wi3] &= ~(((word)-1) << (bi3 + 1));
        else
            m_mant[wi3] |= (((word)-1) << (bi3 + 1));
    }
    for (int i = wi3 + 1; i < size(); ++i) {
        if (under)
            m_mant[i] = 0;
        else
            m_mant[i] = static_cast<word>(-1);
    }

    if (enc == SC_TC_) {
        if (under)
            m_mant[wi] |= (((word)1) << bi);
        else
            m_mant[wi] &= ~(((word)1) << bi);
    }
}

inline void
scfx_rep::o_invert(const scfx_index &x2)
{
    int wi2 = x2.wi();
    int bi2 = x2.bi();

    m_mant[wi2] ^= (((word)-1) << bi2);
    for (int i = wi2 + 1; i < size(); ++i)
        m_mant[i] = ~ m_mant[i];
}

inline bool
scfx_rep::q_bit(const scfx_index &x) const
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    if (bi != 0)
        return (m_mant[wi] & (((word)1) << (bi - 1))) != 0;
    else if (wi != 0)
        return (m_mant[wi - 1] & (((word)1) << (bits_in_word - 1))) != 0;
    else
        return false;
}

inline void
scfx_rep::q_clear(const scfx_index &x)
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    m_mant[wi] &= (((word)-1) << bi);
    for (int i = wi - 1; i >= 0; --i)
        m_mant[i] = 0;
}

inline void
scfx_rep::q_incr(const scfx_index &x)
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    word old_val = m_mant[wi];
    m_mant[wi] += (((word)1) << bi);
    if (m_mant[wi] <= old_val) {
        if (wi + 1 == size())
            resize_to(size() + 1, 1);

        for (int i = wi + 1; i < size(); ++i) {
            if (++m_mant[i] != 0)
                break;
        }
    }
}

inline bool
scfx_rep::q_odd(const scfx_index &x) const
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    return (m_mant[wi] & (((word)1) << bi)) != 0;
}

inline bool
scfx_rep::q_zero(const scfx_index &x) const
{
    int wi = x.wi();
    int bi = x.bi();

    SC_ASSERT_(wi >= 0 && wi < size(), "word index out of range");

    bool zero;

    if (bi != 0) {
        zero = (m_mant[wi] & ~(((word)-1) << (bi - 1))) == 0;
        for (int i = wi - 1; i >= 0; --i)
            zero = zero && m_mant[i] == 0;
    } else if (wi != 0) {
        zero = (m_mant[wi - 1] & ~( ((word)-1) << (bits_in_word - 1))) == 0;
        for (int i = wi - 2; i >= 0; --i)
            zero = zero && m_mant[i] == 0;
    } else {
        zero = true;
    }

    return zero;
}

inline int
scfx_rep::find_lsw() const
{
    for (int i = 0; i < size(); i++) {
        if (m_mant[i])
            return i;
    }
    return 0;
}

inline int
scfx_rep::find_msw() const
{
    for (int i = size() - 1; i >= 0; i--) {
        if (m_mant[i])
            return i;
    }
    return 0;
}

inline void
scfx_rep::find_sw()
{
    m_lsw = find_lsw();
    m_msw = find_msw();
}

inline void
scfx_rep::toggle_tc()
{
    if (is_neg()) {
        complement(m_mant, m_mant, m_mant.size());
        inc(m_mant);
    }
}

} // namespace sc_dt

#endif // __SYSTEMC_EXT_DT_FX_SCFX_REP_HH__