scfx_pow10.cc

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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.
 
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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 "systemc/ext/dt/fx/scfx_pow10.hh"
 
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