scfx_pow10.cpp revision 12027:1eb7dc7aa10b 
1/*****************************************************************************
2
3  Licensed to Accellera Systems Initiative Inc. (Accellera) under one or
4  more contributor license agreements.  See the NOTICE file distributed
5  with this work for additional information regarding copyright ownership.
6  Accellera licenses this file to you under the Apache License, Version 2.0
7  (the "License"); you may not use this file except in compliance with the
8  License.  You may obtain a copy of the License at
9
10    http://www.apache.org/licenses/LICENSE-2.0
11
12  Unless required by applicable law or agreed to in writing, software
13  distributed under the License is distributed on an "AS IS" BASIS,
14  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
15  implied.  See the License for the specific language governing
16  permissions and limitations under the License.
17
18 *****************************************************************************/
19
20/*****************************************************************************
21
22  scfx_pow10.cpp -
23
24  Original Author: Robert Graulich, Synopsys, Inc.
25                   Martin Janssen,  Synopsys, Inc.
26
27 *****************************************************************************/
28
29/*****************************************************************************
30
31  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
32  changes you are making here.
33
34      Name, Affiliation, Date:
35  Description of Modification:
36
37 *****************************************************************************/
38
39
40// $Log: scfx_pow10.cpp,v $
41// Revision 1.1.1.1  2006/12/15 20:20:04  acg
42// SystemC 2.3
43//
44// Revision 1.3  2006/01/13 18:53:58  acg
45// Andy Goodrich: added $Log command so that CVS comments are reproduced in
46// the source.
47//
48
49#include "sysc/datatypes/fx/scfx_pow10.h"
50
51
52namespace sc_dt
53{
54
55// ----------------------------------------------------------------------------
56//  CLASS : scfx_pow10
57//
58//  Class to compute (and cache) powers of 10 in arbitrary precision.
59// ----------------------------------------------------------------------------
60
61scfx_pow10::scfx_pow10()
62{
63    m_pos[0] = scfx_rep( 10.0 );
64    m_neg[0] = scfx_rep( 0.1 );
65
66    for( int i = 1; i < SCFX_POW10_TABLE_SIZE; i ++ )
67    {
68        m_pos[i].set_nan();
69	m_neg[i].set_nan();
70    }
71}
72
73scfx_pow10::~scfx_pow10()
74{}
75
76
77const scfx_rep
78scfx_pow10::operator() ( int i )
79{
80    if( i == 0 ) {
81        return scfx_rep( 1.0 );
82    }
83
84    if( i > 0 )
85    {
86        int bit = scfx_find_msb( i );
87	scfx_rep result = *pos( bit );
88	if( bit )
89	{
90	    while( -- bit >= 0 )
91	    {
92	        if( ( 1 << bit ) & i )
93		{
94		    scfx_rep* tmp = mult_scfx_rep( result, *pos( bit ) );
95		    result = *tmp;
96		    delete tmp;
97		}
98	    }
99	}
100	return result;
101    }
102    else
103    {
104        i = -i;
105	int bit = scfx_find_msb( i );
106	scfx_rep result = *neg( bit );
107	if( bit )
108	{
109	    while( -- bit >= 0 )
110	    {
111	        if( ( 1 << bit ) & i )
112		{
113		    scfx_rep* tmp = mult_scfx_rep( result, *neg( bit ) );
114		    result = *tmp;
115		    delete tmp;
116		}
117	    }
118	}
119	return result;
120    }
121}
122
123
124scfx_rep*
125scfx_pow10::pos( int i )
126{
127    if( ! m_pos[i].is_normal() )
128    {
129        multiply( m_pos[i], *pos( i - 1 ), *pos( i - 1 ) );
130    }
131    return &m_pos[i];
132}
133
134scfx_rep*
135scfx_pow10::neg( int i )
136{
137    if( ! m_neg[i].is_normal() )
138    {
139	multiply( m_neg[i], *neg( i - 1 ), *neg( i - 1 ) );
140    }
141    return &m_neg[i];
142}
143
144} // namespace sc_dt
145
146
147// Taf!
148