xref: /gem5/ext/systemc/src/sysc/datatypes/fx/scfx_pow10.cpp

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  with this work for additional information regarding copyright ownership.
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/*****************************************************************************

  scfx_pow10.cpp -

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

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

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

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

      Name, Affiliation, Date:
  Description of Modification:

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// $Log: scfx_pow10.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 "sysc/datatypes/fx/scfx_pow10.h"


namespace sc_dt
{

// ----------------------------------------------------------------------------
//  CLASS : scfx_pow10
//
//  Class to compute (and cache) powers of 10 in arbitrary precision.
// ----------------------------------------------------------------------------

scfx_pow10::scfx_pow10()
{
    m_pos[0] = scfx_rep( 10.0 );
    m_neg[0] = scfx_rep( 0.1 );

    for( int i = 1; i < SCFX_POW10_TABLE_SIZE; i ++ )
    {
        m_pos[i].set_nan();
	m_neg[i].set_nan();
    }
}

scfx_pow10::~scfx_pow10()
{}


const scfx_rep
scfx_pow10::operator() ( int i )
{
    if( i == 0 ) {
        return scfx_rep( 1.0 );
    }

    if( i > 0 )
    {
        int bit = scfx_find_msb( i );
	scfx_rep result = *pos( bit );
	if( bit )
	{
	    while( -- bit >= 0 )
	    {
	        if( ( 1 << bit ) & i )
		{
		    scfx_rep* tmp = mult_scfx_rep( result, *pos( bit ) );
		    result = *tmp;
		    delete tmp;
		}
	    }
	}
	return result;
    }
    else
    {
        i = -i;
	int bit = scfx_find_msb( i );
	scfx_rep result = *neg( bit );
	if( bit )
	{
	    while( -- bit >= 0 )
	    {
	        if( ( 1 << bit ) & i )
		{
		    scfx_rep* tmp = mult_scfx_rep( result, *neg( bit ) );
		    result = *tmp;
		    delete tmp;
		}
	    }
	}
	return result;
    }
}


scfx_rep*
scfx_pow10::pos( int i )
{
    if( ! m_pos[i].is_normal() )
    {
        multiply( m_pos[i], *pos( i - 1 ), *pos( i - 1 ) );
    }
    return &m_pos[i];
}

scfx_rep*
scfx_pow10::neg( int i )
{
    if( ! m_neg[i].is_normal() )
    {
	multiply( m_neg[i], *neg( i - 1 ), *neg( i - 1 ) );
    }
    return &m_neg[i];
}

} // namespace sc_dt


// Taf!