sc_fxnum.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_fxnum.cpp - 

  Original Author: Martin Janssen, Synopsys, Inc.

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

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

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

      Name, Affiliation, Date:
  Description of Modification:

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


// $Log: sc_fxnum.cpp,v $
// Revision 1.1.1.1  2006/12/15 20:31:36  acg
// SystemC 2.2
//
// Revision 1.3  2006/01/13 18:53:57  acg
// Andy Goodrich: added $Log command so that CVS comments are reproduced in
// the source.
//

#include <math.h>

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


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;