src/systemc/dt/fx/sc_fxval.cc

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  Licensed to Accellera Systems Initiative Inc. (Accellera) under one or
  more contributor license agreements.  See the NOTICE file distributed
  with this work for additional information regarding copyright ownership.
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  (the "License"); you may not use this file except in compliance with the
  License.  You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

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  distributed under the License is distributed on an "AS IS" BASIS,
  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
  implied.  See the License for the specific language governing
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/*****************************************************************************

  sc_fxval.cpp -

  Original Author: Martin Janssen, Synopsys, Inc.

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

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

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

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// $Log: sc_fxval.cpp,v $
// 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.
//

#include <cctype>
#include <cfloat>
#include <cmath>
#include <cstdlib>

#include "systemc/ext/dt/fx/sc_fxval.hh"

namespace sc_dt
{

// ----------------------------------------------------------------------------
//  CLASS : sc_fxval
//
//  Fixed-point value type; arbitrary precision.
// ----------------------------------------------------------------------------

// explicit conversion to character string

const std::string
sc_fxval::to_string() const
{
    return std::string(m_rep->to_string(SC_DEC, -1, SC_E));
}

const std::string
sc_fxval::to_string(sc_numrep numrep) const
{
    return std::string(m_rep->to_string(numrep, -1, SC_E));
}

const std::string
sc_fxval::to_string(sc_numrep numrep, bool w_prefix) const
{
    return std::string(m_rep->to_string(numrep, (w_prefix ? 1 : 0), SC_E));
}

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

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

const std::string
sc_fxval::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));
}


const std::string
sc_fxval::to_dec() const
{
    return std::string(m_rep->to_string(SC_DEC, -1, SC_E));
}

const std::string
sc_fxval::to_bin() const
{
    return std::string(m_rep->to_string(SC_BIN, -1, SC_E));
}

const std::string
sc_fxval::to_oct() const
{
    return std::string(m_rep->to_string(SC_OCT, -1, SC_E));
}

const std::string
sc_fxval::to_hex() const
{
    return std::string(m_rep->to_string(SC_HEX, -1, SC_E));
}


// print or dump content

void sc_fxval::print(::std::ostream &os) const { m_rep->print(os); }

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

void
sc_fxval::dump(::std::ostream &os) const
{
    os << "sc_fxval" << ::std::endl;
    os << "(" << ::std::endl;
    os << "rep = ";
    m_rep->dump(os);
    // TO BE COMPLETED
    // os << "r_flag   = " << m_r_flag << ::std::endl;
    // os << "observer = ";
    // if (m_observer != 0)
    //     m_observer->dump(os);
    // else
    //     os << "0" << ::std::endl;
    os << ")" << ::std::endl;
}

// protected methods and friend functions
sc_fxval_observer *
sc_fxval::lock_observer() const
{
    SC_ASSERT_(m_observer != 0, "lock observer failed");
    sc_fxval_observer *tmp = m_observer;
    m_observer = 0;
    return tmp;
}

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


// ----------------------------------------------------------------------------
//  CLASS : sc_fxval_fast
//
//  Fixed-point value types; limited precision.
// ----------------------------------------------------------------------------

static void
print_dec(scfx_string &s, scfx_ieee_double id, int w_prefix, sc_fmt fmt)
{
    if (id.negative() != 0) {
        id.negative(0);
        s += '-';
    }

    if (w_prefix == 1) {
        scfx_print_prefix(s, SC_DEC);
    }

    if (id.is_zero()) {
        s += '0';
        return;
    }

    // split 'id' into its integer and fractional part
    double int_part;
    double frac_part = std::modf(static_cast<double>(id), &int_part);

    int i;

    // print integer part
    int int_digits = 0;
    int int_zeros  = 0;

    if (int_part != 0.0) {
        int_digits = (int)std::ceil(std::log10(int_part + 1.0));

        int len = s.length();
        s.append(int_digits);

        bool zero_digits = (frac_part == 0.0 && fmt != SC_F);

        for (i = int_digits + len - 1; i >= len; i--) {
            unsigned int remainder = (unsigned int)std::fmod(int_part, 10.0);
            s[i] = static_cast<char>('0' + remainder);

            if (zero_digits) {
                if (remainder == 0)
                    int_zeros++;
                else
                    zero_digits = false;
            }

            int_part /= 10.0;
        }

        // discard trailing zeros from int_part
        s.discard(int_zeros);

        if (s[len] == '0') {
            // int_digits was overestimated by one
            s.remove(len);
            --int_digits;
        }
    }

    // print fractional part
    int frac_digits = 0;
    int frac_zeros  = 0;

    if (frac_part != 0.0) {
        s += '.';

        bool zero_digits = (int_digits == 0 && fmt != SC_F);

        frac_zeros = (int)std::floor(-std::log10(frac_part + DBL_EPSILON));

        frac_part *= std::pow(10.0, frac_zeros);

        frac_digits = frac_zeros;
        if (!zero_digits) {
            for (i = 0; i < frac_zeros; i++)
                s += '0';
            frac_zeros = 0;
        }

        while (frac_part != 0.0) {
            frac_part *= 10.0;
            int n = static_cast<int>(frac_part);

            if (zero_digits) {
                if (n == 0)
                    frac_zeros++;
                else
                    zero_digits = false;
            }

            if (!zero_digits)
                s += static_cast<char>('0' + n);

            frac_part -= n;
            frac_digits++;
        }
    }

    // print exponent
    if (fmt != SC_F) {
        if (frac_digits == 0)
            scfx_print_exp(s, int_zeros);
        else if (int_digits == 0)
            scfx_print_exp(s, -frac_zeros);
    }
}

static void
print_other(scfx_string &s, const scfx_ieee_double &id, sc_numrep numrep,
             int w_prefix, sc_fmt fmt, const scfx_params *params)
{
    scfx_ieee_double id2 = id;

    sc_numrep numrep2 = numrep;

    bool numrep_is_sm = (numrep == SC_BIN_SM ||
                         numrep == SC_OCT_SM ||
                         numrep == SC_HEX_SM);

    if (numrep_is_sm) {
        if (id2.negative() != 0) {
            s += '-';
            id2.negative(0);
        }
        switch (numrep) {
          case SC_BIN_SM:
            numrep2 = SC_BIN_US;
            break;
          case SC_OCT_SM:
            numrep2 = SC_OCT_US;
            break;
          case SC_HEX_SM:
            numrep2 = SC_HEX_US;
            break;
          default:
            ;
        }
    }

    if (w_prefix != 0) {
        scfx_print_prefix(s, numrep);
    }

    numrep = numrep2;

    sc_fxval_fast a(id2);

    int msb, lsb;

    if (params != 0) {
        msb = params->iwl() - 1;
        lsb = params->iwl() - params->wl();

        if (params->enc() == SC_TC_ &&
            (numrep == SC_BIN_US ||
              numrep == SC_OCT_US ||
              numrep == SC_HEX_US) &&
            !numrep_is_sm &&
            params->wl() > 1) {
            --msb;
        } else if (params->enc() == SC_US_ &&
            (numrep == SC_BIN ||
              numrep == SC_OCT ||
              numrep == SC_HEX ||
              numrep == SC_CSD)) {
            ++msb;
        }
    } else {
        if (a.is_zero()) {
            msb = 0;
            lsb = 0;
        } else {
            msb = id2.exponent() + 1;
            while (a.get_bit(msb) == a.get_bit(msb - 1))
                --msb;

            if (numrep == SC_BIN_US ||
                numrep == SC_OCT_US ||
                numrep == SC_HEX_US) {
                --msb;
            }

            lsb = id2.exponent() - 52;
            while (!a.get_bit(lsb))
                ++lsb;
        }
    }

    int step;

    switch (numrep) {
      case SC_BIN:
      case SC_BIN_US:
      case SC_CSD:
        step = 1;
       break;
      case SC_OCT:
      case SC_OCT_US:
        step = 3;
        break;
      case SC_HEX:
      case SC_HEX_US:
        step = 4;
        break;
      default:
        SC_REPORT_FATAL("assertion failed", "unexpected sc_numrep");
        sc_core::sc_abort();
    }

    msb = (int)std::ceil(double(msb + 1) / step) * step - 1;

    lsb = (int)std::floor(double(lsb) / step) * step;

    if (msb < 0) {
        s += '.';
        if (fmt == SC_F) {
            int sign = (id2.negative() != 0) ? (1 << step) - 1 : 0;
            for (int i = (msb + 1) / step; i < 0; i++) {
                if (sign < 10)
                    s += static_cast<char>(sign + '0');
                else
                    s += static_cast<char>(sign + 'a' - 10);
            }
        }
    }

    int i = msb;
    while (i >= lsb) {
        int value = 0;
        for (int j = step - 1; j >= 0; --j) {
            value += static_cast<int>(a.get_bit(i)) << j;
            --i;
        }
        if (value < 10)
            s += static_cast<char>(value + '0');
        else
            s += static_cast<char>(value + 'a' - 10);
        if (i == -1)
            s += '.';
    }

    if (lsb > 0 && fmt == SC_F) {
        for (int i = lsb / step; i > 0; i--)
            s += '0';
    }

    if (s[s.length() - 1] == '.')
        s.discard(1);

    if (fmt != SC_F) {
        if (msb < 0)
            scfx_print_exp(s, (msb + 1) / step);
        else if (lsb > 0)
            scfx_print_exp(s, lsb / step);
    }

    if (numrep == SC_CSD)
        scfx_tc2csd(s, w_prefix);
}

const char *
to_string(const scfx_ieee_double &id, sc_numrep numrep, int w_prefix,
          sc_fmt fmt, const scfx_params *params=0)
{
    static scfx_string s;

    s.clear();

    if (id.is_nan()) {
        scfx_print_nan(s);
    } else if (id.is_inf()) {
        scfx_print_inf(s, static_cast<bool>(id.negative()));
    } else if (id.negative() && !id.is_zero() &&
             (numrep == SC_BIN_US ||
               numrep == SC_OCT_US ||
               numrep == SC_HEX_US)) {
        s += "negative";
    } else if (numrep == SC_DEC) {
        sc_dt::print_dec(s, id, w_prefix, fmt);
    } else {
        sc_dt::print_other(s, id, numrep, w_prefix, fmt, params);
    }

    return s;
}


// explicit conversion to character string
const std::string
sc_fxval_fast::to_string() const
{
    return std::string(sc_dt::to_string(m_val, SC_DEC, -1, SC_E));
}

const std::string
sc_fxval_fast::to_string(sc_numrep numrep) const
{
    return std::string(sc_dt::to_string(m_val, numrep, -1, SC_E));
}

const std::string
sc_fxval_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_E));
}

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

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

const std::string
sc_fxval_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));
}

const std::string
sc_fxval_fast::to_dec() const
{
    return std::string(sc_dt::to_string(m_val, SC_DEC, -1, SC_E));
}

const std::string
sc_fxval_fast::to_bin() const
{
    return std::string(sc_dt::to_string(m_val, SC_BIN, -1, SC_E));
}

const std::string
sc_fxval_fast::to_oct() const
{
    return std::string(sc_dt::to_string(m_val, SC_OCT, -1, SC_E));
}

const std::string
sc_fxval_fast::to_hex() const
{
    return std::string(sc_dt::to_string(m_val, SC_HEX, -1, SC_E));
}


// print or dump content

void
sc_fxval_fast::print(::std::ostream &os) const
{
    os << sc_dt::to_string(m_val, SC_DEC, -1, SC_E);
}

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

void
sc_fxval_fast::dump(::std::ostream &os) const
{
    os << "sc_fxval_fast" << ::std::endl;
    os << "(" << ::std::endl;
    os << "val = " << m_val << ::std::endl;
    // TO BE COMPLETED
    // os << "r_flag   = " << m_r_flag << ::std::endl;
    // os << "observer = ";
    // if (m_observer != 0)
    //     m_observer->dump(os);
    // else
    //     os << "0" << ::std::endl;
    os << ")" << ::std::endl;
}


// internal use only;
bool
sc_fxval_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;
}


// protected methods and friend functions
sc_fxval_fast_observer *
sc_fxval_fast::lock_observer() const
{
    SC_ASSERT_(m_observer != 0, "lock observer failed");
    sc_fxval_fast_observer *tmp = m_observer;
    m_observer = 0;
    return tmp;
}

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

#define SCFX_FAIL_IF_(cnd)                                                    \
{                                                                             \
    if ((cnd))                                                             \
        return static_cast<double>(scfx_ieee_double::nan());                \
}

double
sc_fxval_fast::from_string(const char *s)
{
    SCFX_FAIL_IF_(s == 0 || *s == 0);

    scfx_string s2;
    s2 += s;
    s2 += '\0';

    bool sign_char;
    int sign = scfx_parse_sign(s, sign_char);

    sc_numrep numrep = scfx_parse_prefix(s);

    int base = 0;

    switch (numrep) {
      case SC_DEC:
        {
            base = 10;
            if (scfx_is_nan(s)) // special case: NaN
                return static_cast<double>(scfx_ieee_double::nan());
            if (scfx_is_inf(s)) // special case: Infinity
                return static_cast<double>(scfx_ieee_double::inf(sign));
            break;
        }
      case SC_BIN:
      case SC_BIN_US:
        {
            SCFX_FAIL_IF_(sign_char);
            base = 2;
            break;
        }

      case SC_BIN_SM:
        {
            base = 2;
            break;
        }
      case SC_OCT:
      case SC_OCT_US:
        {
            SCFX_FAIL_IF_(sign_char);
            base = 8;
            break;
        }
      case SC_OCT_SM:
        {
            base = 8;
            break;
        }
      case SC_HEX:
      case SC_HEX_US:
        {
            SCFX_FAIL_IF_(sign_char);
            base = 16;
            break;
        }
      case SC_HEX_SM:
        {
            base = 16;
            break;
        }
      case SC_CSD:
        {
            SCFX_FAIL_IF_(sign_char);
            base = 2;
            scfx_csd2tc(s2);
            s = (const char*) s2 + 4;
            numrep = SC_BIN;
            break;
        }
      default:;// Martin, what is default???
    }

    //
    // find end of mantissa and count the digits and points
    //

    const char *end = s;
    bool based_point = false;
    int int_digits = 0;
    int frac_digits = 0;

    while (*end) {
        if (scfx_exp_start(end))
            break;

        if (*end == '.') {
            SCFX_FAIL_IF_(based_point);
            based_point = true;
        } else {
            SCFX_FAIL_IF_(!scfx_is_digit(*end, numrep));
            if (based_point)
                frac_digits++;
            else
                int_digits++;
        }

        end++;
    }

    SCFX_FAIL_IF_(int_digits == 0 && frac_digits == 0);

    // [ exponent ]
    int exponent = 0;
    if (*end) {
        for (const char *e = end + 2; *e; e++)
            SCFX_FAIL_IF_(!scfx_is_digit(*e, SC_DEC));
        exponent = std::atoi(end + 1);
    }

    //
    // convert the mantissa
    //
    double integer = 0.0;
    if (int_digits != 0) {
        bool first_digit = true;

        for (; s < end; s++) {
            if (*s == '.')
                break;

            if (first_digit) {
                integer = scfx_to_digit(*s, numrep);
                switch (numrep) {
                  case SC_BIN:
                  case SC_OCT:
                  case SC_HEX:
                    {
                        if (integer >= (base >> 1))
                            integer -= base; // two's complement
                        break;
                    }
                  default:
                    ;
                }
                first_digit = false;
            } else {
                integer *= base;
                integer += scfx_to_digit(*s, numrep);
            }
        }
    }

    // [ . fraction ]
    double fraction = 0.0;
    if (frac_digits != 0) {
        s++;  // skip '.'

        bool first_digit = (int_digits == 0);
        double scale = 1.0;
        for (; s < end; s++) {
            scale /= base;

            if (first_digit) {
                fraction = scfx_to_digit(*s, numrep);
                switch (numrep) {
                  case SC_BIN:
                  case SC_OCT:
                  case SC_HEX:
                    {
                        if (fraction >= (base >> 1))
                            fraction -= base; // two's complement
                        break;
                    }
                  default:
                    ;
                }
                fraction *= scale;
                first_digit = false;
            } else {
                fraction += scfx_to_digit(*s, numrep) * scale;
            }
        }
    }

    double exp =
        (exponent != 0) ? std::pow((double) base, (double) exponent) : 1;

    return (sign * (integer + fraction) * exp);
}

#undef SCFX_FAIL_IF_

} // namespace sc_dt