sc_fxval.cpp

system C源码 一种替代verilog的语言

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

  The following code is derived, directly or indirectly, from the SystemC
  source code Copyright (c) 1996-2006 by all Contributors.
  All Rights reserved.

  The contents of this file are subject to the restrictions and limitations
  set forth in the SystemC Open Source License Version 2.4 (the "License");
  You may not use this file except in compliance with such restrictions and
  limitations. You may obtain instructions on how to receive a copy of the
  License at http://www.systemc.org/. Software distributed by Contributors
  under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
  ANY KIND, either express or implied. See the License for the specific
  language governing rights and limitations under the License.

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

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

  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 20:31:36  acg
// SystemC 2.2
//
// 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 <ctype.h>
#include <math.h>
#include <float.h>

#include "sysc/datatypes/fx/sc_fxval.h"


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 = 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) ceil( 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) 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) floor( - log10( frac_part + DBL_EPSILON ) );

	frac_part *= 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:
	    step = 0;
    }

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

    lsb = (int) 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 )
    {