xref: /gem5/src/systemc/dt/fx/sc_fxnum.cc

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  more contributor license agreements.  See the NOTICE file distributed
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  (the "License"); you may not use this file except in compliance with the
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/*****************************************************************************

  sc_fxnum.cpp -

  Original Author: Martin Janssen, Synopsys, Inc.

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

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

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// $Log: sc_fxnum.cpp,v $
// Revision 1.3  2011/01/19 18:57:40  acg
//  Andy Goodrich: changes for IEEE_1666_2011.
//
// Revision 1.2  2010/12/07 20:09:08  acg
// Andy Goodrich: Philipp Hartmann's constructor disambiguation fix
//
// Revision 1.1.1.1  2006/12/15 20:20:04  acg
// SystemC 2.3
//
// Revision 1.3  2006/01/13 18:53:57  acg
// Andy Goodrich: added $Log command so that CVS comments are reproduced in
// the source.
//

#include <cmath>

#include "systemc/ext/dt/fx/messages.hh"
#include "systemc/ext/dt/fx/sc_fxnum.hh"

namespace sc_dt
{

// ----------------------------------------------------------------------------
//  CLASS : sc_fxnum_bitref
//
//  Proxy class for bit-selection in class sc_fxnum, behaves like sc_bit.
// ----------------------------------------------------------------------------

bool sc_fxnum_bitref::get() const { return m_num.get_bit(m_idx); }
void sc_fxnum_bitref::set(bool high) { m_num.set_bit(m_idx, high); }

// print or dump content
void sc_fxnum_bitref::print(::std::ostream &os) const { os << get(); }

void
sc_fxnum_bitref::scan(::std::istream &is)
{
    bool b;
    is >> b;
    *this = b;
}

void
sc_fxnum_bitref::dump(::std::ostream &os) const
{
    os << "sc_fxnum_bitref" << ::std::endl;
    os << "(" << ::std::endl;
    os << "num = ";
    m_num.dump(os);
    os << "idx = " << m_idx << ::std::endl;
    os << ")" << ::std::endl;
}


// ----------------------------------------------------------------------------
//  CLASS : sc_fxnum_fast_bitref
//
//  Proxy class for bit-selection in class sc_fxnum_fast, behaves like sc_bit.
// ----------------------------------------------------------------------------

bool sc_fxnum_fast_bitref::get() const { return m_num.get_bit(m_idx); }
void sc_fxnum_fast_bitref::set(bool high) { m_num.set_bit(m_idx, high); }

// print or dump content
void sc_fxnum_fast_bitref::print(::std::ostream &os) const { os << get(); }

void
sc_fxnum_fast_bitref::scan(::std::istream &is)
{
    bool b;
    is >> b;
    *this = b;
}

void
sc_fxnum_fast_bitref::dump(::std::ostream &os) const
{
    os << "sc_fxnum_fast_bitref" << ::std::endl;
    os << "(" << ::std::endl;
    os << "num = ";
    m_num.dump(os);
    os << "idx = " << m_idx << ::std::endl;
    os << ")" << ::std::endl;
}

// ----------------------------------------------------------------------------
//  CLASS : sc_fxnum_subref
//
//  Proxy class for part-selection in class sc_fxnum,
//  behaves like sc_bv_base.
// ----------------------------------------------------------------------------

bool
sc_fxnum_subref::get() const
{
    return m_num.get_slice(m_from, m_to, m_bv);
}

bool
sc_fxnum_subref::set()
{
    return m_num.set_slice(m_from, m_to, m_bv);
}

// print or dump content
void
sc_fxnum_subref::print(::std::ostream &os) const
{
    get();
    m_bv.print(os);
}

void
sc_fxnum_subref::scan(::std::istream &is)
{
    m_bv.scan(is);
    set();
}

void
sc_fxnum_subref::dump(::std::ostream &os) const
{
    os << "sc_fxnum_subref" << ::std::endl;
    os << "(" << ::std::endl;
    os << "num  = ";
    m_num.dump(os);
    os << "from = " << m_from << ::std::endl;
    os << "to   = " << m_to << ::std::endl;
    os << ")" << ::std::endl;
}


// ----------------------------------------------------------------------------
//  CLASS : sc_fxnum_fast_subref
//
//  Proxy class for part-selection in class sc_fxnum_fast,
//  behaves like sc_bv_base.
// ----------------------------------------------------------------------------

bool
sc_fxnum_fast_subref::get() const
{
    return m_num.get_slice(m_from, m_to, m_bv);
}

bool
sc_fxnum_fast_subref::set()
{
    return m_num.set_slice(m_from, m_to, m_bv);
}

// print or dump content
void
sc_fxnum_fast_subref::print(::std::ostream &os) const
{
    get();
    m_bv.print(os);
}

void
sc_fxnum_fast_subref::scan(::std::istream &is)
{
    m_bv.scan(is);
    set();
}

void
sc_fxnum_fast_subref::dump(::std::ostream &os) const
{
    os << "sc_fxnum_fast_subref" << ::std::endl;
    os << "(" << ::std::endl;
    os << "num  = ";
    m_num.dump(os);
    os << "from = " << m_from << ::std::endl;
    os << "to   = " << m_to << ::std::endl;
    os << ")" << ::std::endl;
}


// ----------------------------------------------------------------------------
//  CLASS : sc_fxnum
//
//  Base class for the fixed-point types; arbitrary precision.
// ----------------------------------------------------------------------------

// explicit conversion to character string

const std::string
sc_fxnum::to_string() const
{
    return std::string(m_rep->to_string(SC_DEC, -1, SC_F, &m_params));
}

const std::string
sc_fxnum::to_string(sc_numrep numrep) const
{
    return std::string(m_rep->to_string(numrep, -1, SC_F, &m_params));
}

const std::string
sc_fxnum::to_string(sc_numrep numrep, bool w_prefix) const
{
    return std::string(m_rep->to_string(numrep, (w_prefix ? 1 : 0),
                                        SC_F, &m_params));
}

const std::string
sc_fxnum::to_string(sc_fmt fmt) const
{
    return std::string(m_rep->to_string(SC_DEC, -1, fmt, &m_params));
}

const std::string
sc_fxnum::to_string(sc_numrep numrep, sc_fmt fmt) const
{
    return std::string(m_rep->to_string(numrep, -1, fmt, &m_params));
}

const std::string
sc_fxnum::to_string(sc_numrep numrep, bool w_prefix, sc_fmt fmt) const
{
    return std::string(m_rep->to_string(numrep, (w_prefix ? 1 : 0),
                                        fmt, &m_params));
}


const std::string
sc_fxnum::to_dec() const
{
    return std::string(m_rep->to_string(SC_DEC, -1, SC_F, &m_params));
}

const std::string
sc_fxnum::to_bin() const
{
    return std::string(m_rep->to_string(SC_BIN, -1, SC_F, &m_params));
}

const std::string
sc_fxnum::to_oct() const
{
    return std::string(m_rep->to_string(SC_OCT, -1, SC_F, &m_params));
}

const std::string
sc_fxnum::to_hex() const
{
    return std::string(m_rep->to_string(SC_HEX, -1, SC_F, &m_params));
}


// print or dump content
void
sc_fxnum::print(::std::ostream &os) const
{
    os << m_rep->to_string(SC_DEC, -1, SC_F, &m_params);
}

void
sc_fxnum::scan(::std::istream &is)
{
    std::string s;
    is >> s;
    *this = s.c_str();
}

void
sc_fxnum::dump(::std::ostream &os) const
{
    os << "sc_fxnum" << ::std::endl;
    os << "(" << ::std::endl;
    os << "rep      = ";
    m_rep->dump(os);
    os << "params   = ";
    m_params.dump(os);
    os << "q_flag   = " << m_q_flag << ::std::endl;
    os << "o_flag   = " << m_o_flag << ::std::endl;
    // TO BE COMPLETED
    // os << "observer = ";
    // if (m_observer != 0)
    //     m_observer->dump(os);
    // else
    //     os << "0" << ::std::endl;
    os << ")" << ::std::endl;
}


sc_fxnum_observer *
sc_fxnum::lock_observer() const
{
    SC_ASSERT_(m_observer != 0, "lock observer failed");
    sc_fxnum_observer * tmp = m_observer;
    m_observer = 0;
    return tmp;
}

void
sc_fxnum::unlock_observer(sc_fxnum_observer *observer_) const
{
    SC_ASSERT_(observer_ != 0, "unlock observer failed");
    m_observer = observer_;
}


// ----------------------------------------------------------------------------
//  CLASS : sc_fxnum_fast
//
//  Base class for the fixed-point types; limited precision.
// ----------------------------------------------------------------------------

static void
quantization(double &c, const scfx_params &params, bool &q_flag)
{
    int fwl = params.wl() - params.iwl();
    double scale = scfx_pow2(fwl);
    double val = scale * c;
    double int_part;
    double frac_part = modf(val, &int_part);

    q_flag = (frac_part != 0.0);

    if (q_flag) {
        val = int_part;

        switch (params.q_mode()) {
          case SC_TRN: // truncation
            {
                if (c < 0.0)
                    val -= 1.0;
                break;
            }
          case SC_RND: // rounding to plus infinity
            {
                if (frac_part >= 0.5)
                    val += 1.0;
                else if (frac_part < -0.5)
                    val -= 1.0;
                break;
            }
          case SC_TRN_ZERO: // truncation to zero
            {
                break;
            }
          case SC_RND_INF: // rounding to infinity
            {
                if (frac_part >= 0.5)
                    val += 1.0;
                else if (frac_part <= -0.5)
                    val -= 1.0;
                break;
            }
          case SC_RND_CONV: // convergent rounding
            {
                if (frac_part > 0.5 ||
                    (frac_part == 0.5 && fmod(int_part, 2.0) != 0.0)) {
                    val += 1.0;
                } else if (frac_part < -0.5 ||
                           (frac_part == -0.5 && fmod(int_part, 2.0) != 0.0)) {
                    val -= 1.0;
                }
                break;
            }
          case SC_RND_ZERO: // rounding to zero
            {
                if (frac_part > 0.5)
                    val += 1.0;
                else if (frac_part < -0.5)
                    val -= 1.0;
                break;
            }
          case SC_RND_MIN_INF: // rounding to minus infinity
            {
                if (frac_part > 0.5)
                    val += 1.0;
                else if (frac_part <= -0.5)
                    val -= 1.0;
                break;
            }
          default:
            ;
        }
    }

    val /= scale;
    c = val;
}

static void
overflow(double &c, const scfx_params &params, bool &o_flag)
{
    int iwl = params.iwl();
    int fwl = params.wl() - iwl;
    double full_circle = scfx_pow2(iwl);
    double resolution = scfx_pow2(-fwl);
    double low, high;
    if (params.enc() == SC_TC_) {
        high = full_circle / 2.0 - resolution;
        if (params.o_mode() == SC_SAT_SYM)
            low = - high;
        else
            low = - full_circle / 2.0;
    } else {
        low = 0.0;
        high = full_circle - resolution;
    }
    double val = c;
    sc_fxval_fast c2(c);

    bool under = (val < low);
    bool over = (val > high);

    o_flag = (under || over);

    if (o_flag) {
        switch (params.o_mode()) {
          case SC_WRAP: // wrap-around
            {
                int n_bits = params.n_bits();

                if (n_bits == 0) {
                    // wrap-around all 'wl' bits
                    val -= floor(val / full_circle) * full_circle;
                    if (val > high)
                        val -= full_circle;
                } else if (n_bits < params.wl()) {
                    double X = scfx_pow2(iwl - n_bits);

                    // wrap-around least significant 'wl - n_bits' bits
                    val -= floor(val / X) * X;
                    if (val > (X - resolution))
                        val -= X;

                    // saturate most significant 'n_bits' bits
                    if (under) {
                        val += low;
                    } else {
                        if (params.enc() == SC_TC_)
                            val += full_circle / 2.0 - X;
                        else
                            val += full_circle - X;
                    }
                } else {
                    // saturate all 'wl' bits
                    if (under)
                        val = low;
                    else
                        val = high;
                }
                break;
            }
          case SC_SAT: // saturation
          case SC_SAT_SYM: // symmetrical saturation
            {
                if (under)
                    val = low;
                else
                    val = high;
                break;
            }
          case SC_SAT_ZERO: // saturation to zero
            {
                val = 0.0;
                break;
            }
          case SC_WRAP_SM: // sign magnitude wrap-around
            {
                SC_ERROR_IF_(params.enc() == SC_US_,
                             sc_core::SC_ID_WRAP_SM_NOT_DEFINED_);

                int n_bits = params.n_bits();

                if (n_bits == 0) {
                    // invert conditionally
                    if (c2.get_bit(iwl) != c2.get_bit(iwl - 1))
                        val = -val - resolution;

                    // wrap-around all 'wl' bits
                    val -= floor(val / full_circle) * full_circle;
                    if (val > high)
                        val -= full_circle;
                } else if (n_bits == 1) {
                    // invert conditionally
                    if (c2.is_neg() != c2.get_bit(iwl - 1))
                        val = -val - resolution;

                    // wrap-around all 'wl' bits
                    val -= floor(val / full_circle) * full_circle;
                    if (val > high)
                        val -= full_circle;
                } else if (n_bits < params.wl()) {
                    // invert conditionally
                    if (c2.is_neg() == c2.get_bit(iwl - n_bits))
                        val = -val - resolution;

                    double X = scfx_pow2(iwl - n_bits);

                    // wrap-around least significant 'wl - n_bits' bits
                    val -= floor(val / X) * X;
                    if (val > (X - resolution))
                        val -= X;

                    // saturate most significant 'n_bits' bits
                    if (under)
                        val += low;
                    else
                        val += full_circle / 2.0 - X;
                } else {
                    // saturate all 'wl' bits
                    if (under)
                        val = low;
                    else
                        val = high;
                }
                break;
            }
            default:
                ;
        }

        c = val;
    }
}


void
sc_fxnum_fast::cast()
{
    scfx_ieee_double id(m_val);
    SC_ERROR_IF_(id.is_nan() || id.is_inf(), sc_core::SC_ID_INVALID_FX_VALUE_);

    if (m_params.cast_switch() == SC_ON) {
        m_q_flag = false;
        m_o_flag = false;

        // check for special cases

        if (id.is_zero()) {
            if (id.negative() != 0)
                m_val = -m_val;
            return;
        }

        // perform casting
        sc_dt::quantization(m_val, m_params, m_q_flag);
        sc_dt::overflow(m_val, m_params, m_o_flag);

        // check for special case: -0
        id = m_val;
        if (id.is_zero() && id.negative() != 0) {
            m_val = -m_val;
        }

        // check for special case: NaN of Inf
        if (id.is_nan() || id.is_inf()) {
            m_val = 0.0;
        }
    }
}


// defined in sc_fxval.cpp;
extern const char* to_string(const scfx_ieee_double &, sc_numrep, int, sc_fmt,
                             const scfx_params * =0);


// explicit conversion to character string

const std::string
sc_fxnum_fast::to_string() const
{
    return std::string(sc_dt::to_string(m_val, SC_DEC, -1, SC_F, &m_params));
}

const std::string
sc_fxnum_fast::to_string(sc_numrep numrep) const
{
    return std::string(sc_dt::to_string(m_val, numrep, -1, SC_F, &m_params));
}

const std::string
sc_fxnum_fast::to_string(sc_numrep numrep, bool w_prefix) const
{
    return std::string(sc_dt::to_string(m_val, numrep, (w_prefix ? 1 : 0),
                                        SC_F, &m_params));
}

const std::string
sc_fxnum_fast::to_string(sc_fmt fmt) const
{
    return std::string(sc_dt::to_string(m_val, SC_DEC, -1, fmt, &m_params));
}

const std::string
sc_fxnum_fast::to_string(sc_numrep numrep, sc_fmt fmt) const
{
    return std::string(sc_dt::to_string(m_val, numrep, -1, fmt, &m_params));
}

const std::string
sc_fxnum_fast::to_string(sc_numrep numrep, bool w_prefix, sc_fmt fmt) const
{
    return std::string(sc_dt::to_string(m_val, numrep, (w_prefix ? 1 : 0),
                                        fmt, &m_params));
}


const std::string
sc_fxnum_fast::to_dec() const
{
    return std::string(sc_dt::to_string(m_val, SC_DEC, -1, SC_F, &m_params));
}

const std::string
sc_fxnum_fast::to_bin() const
{
    return std::string(sc_dt::to_string(m_val, SC_BIN, -1, SC_F, &m_params));
}

const std::string
sc_fxnum_fast::to_oct() const
{
    return std::string(sc_dt::to_string(m_val, SC_OCT, -1, SC_F, &m_params));
}

const std::string
sc_fxnum_fast::to_hex() const
{
    return std::string(sc_dt::to_string(m_val, SC_HEX, -1, SC_F, &m_params));
}

// print or dump content
void
sc_fxnum_fast::print(::std::ostream &os) const
{
    os << sc_dt::to_string(m_val, SC_DEC, -1, SC_F, &m_params);
}

void
sc_fxnum_fast::scan(::std::istream &is)
{
    std::string s;
    is >> s;
    *this = s.c_str();
}

void
sc_fxnum_fast::dump(::std::ostream &os) const
{
    os << "sc_fxnum_fast" << ::std::endl;
    os << "(" << ::std::endl;
    os << "val      = " << m_val << ::std::endl;
    os << "params   = ";
    m_params.dump(os);
    os << "q_flag   = " << m_q_flag << ::std::endl;
    os << "o_flag   = " << m_o_flag << ::std::endl;
    // TO BE COMPLETED
    // os << "observer = ";
    // if (m_observer != 0)
    //     m_observer->dump(os);
    // else
    //     os << "0" << ::std::endl;
    os << ")" << ::std::endl;
}

// internal use only;
bool
sc_fxnum_fast::get_bit(int i) const
{
    scfx_ieee_double id(m_val);
    if (id.is_zero() || id.is_nan() || id.is_inf())
        return false;

    // convert to two's complement
    unsigned int m0 = id.mantissa0();
    unsigned int m1 = id.mantissa1();

    if (id.is_normal())
        m0 += 1U << 20;

    if (id.negative() != 0) {
        m0 = ~ m0;
        m1 = ~ m1;
        unsigned int tmp = m1;
        m1 += 1U;
        if (m1 <= tmp)
            m0 += 1U;
    }

    // get the right bit
    int j = i - id.exponent();
    if ((j += 20) >= 32)
        return ((m0 & 1U << 31) != 0);
    else if (j >= 0)
        return ((m0 & 1U << j) != 0);
    else if ((j += 32) >= 0)
        return ((m1 & 1U << j) != 0);
    else
        return false;
}


bool
sc_fxnum_fast::set_bit(int i, bool high)
{
    scfx_ieee_double id(m_val);
    if (id.is_nan() || id.is_inf())
        return false;

    if (high) {
        if (get_bit(i))
            return true;

        if (m_params.enc() == SC_TC_ && i == m_params.iwl() - 1)
            m_val -= scfx_pow2(i);
        else
            m_val += scfx_pow2(i);
    } else {
        if (!get_bit(i))
            return true;

        if (m_params.enc() == SC_TC_ && i == m_params.iwl() - 1)
            m_val += scfx_pow2(i);
        else
            m_val -= scfx_pow2(i);
    }

    return true;
}


bool
sc_fxnum_fast::get_slice(int i, int j, sc_bv_base &bv) const
{
    scfx_ieee_double id(m_val);
    if (id.is_nan() || id.is_inf())
        return false;

    // convert to two's complement
    unsigned int m0 = id.mantissa0();
    unsigned int m1 = id.mantissa1();

    if (id.is_normal())
        m0 += 1U << 20;

    if (id.negative() != 0) {
        m0 = ~ m0;
        m1 = ~ m1;
        unsigned int tmp = m1;
        m1 += 1U;
        if (m1 <= tmp)
            m0 += 1U;
    }

    // get the bits
    int l = j;
    for (int k = 0; k < bv.length(); ++ k) {
        bool b = false;

        int n = l - id.exponent();
        if ((n += 20) >= 32)
            b = ((m0 & 1U << 31) != 0);
        else if (n >= 0)
            b = ((m0 & 1U << n) != 0);
        else if ((n += 32) >= 0)
            b = ((m1 & 1U << n) != 0);

        bv[k] = b;

        if (i >= j)
            ++l;
        else
            --l;
    }

    return true;
}

bool
sc_fxnum_fast::set_slice(int i, int j, const sc_bv_base &bv)
{
    scfx_ieee_double id(m_val);
    if (id.is_nan() || id.is_inf())
        return false;

    // set the bits
    int l = j;
    for (int k = 0; k < bv.length(); ++k) {
        if (bv[k].to_bool()) {
            if (!get_bit(l)) {
                if (m_params.enc() == SC_TC_ && l == m_params.iwl() - 1)
                    m_val -= scfx_pow2(l);
                else
                    m_val += scfx_pow2(l);
            }
        } else {
            if (get_bit(l)) {
                if (m_params.enc() == SC_TC_ && l == m_params.iwl() - 1)
                    m_val += scfx_pow2(l);
                else
                    m_val -= scfx_pow2(l);
            }
        }

        if (i >= j)
            ++l;
        else
            --l;
    }

    return true;
}

sc_fxnum_fast_observer *
sc_fxnum_fast::lock_observer() const
{
    SC_ASSERT_(m_observer != 0, "lock observer failed");
    sc_fxnum_fast_observer *tmp = m_observer;
    m_observer = 0;
    return tmp;
}

void
sc_fxnum_fast::unlock_observer(sc_fxnum_fast_observer *observer_) const
{
    SC_ASSERT_(observer_ != 0, "unlock observer failed");
    m_observer = observer_;
}

} // namespace sc_dt