scfx_utils.cc revision 12854 
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20/*****************************************************************************
21
22  scfx_utils.cpp -
23
24  Original Author: Martin Janssen, Synopsys, Inc.
25
26 *****************************************************************************/
27
28/*****************************************************************************
29
30  MODIFICATION LOG - modifiers, enter your name, affiliation, date and
31  changes you are making here.
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33      Name, Affiliation, Date:
34  Description of Modification:
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37
38
39// $Log: scfx_utils.cpp,v $
40// Revision 1.1.1.1  2006/12/15 20:20:04  acg
41// SystemC 2.3
42//
43// Revision 1.3  2006/01/13 18:53:58  acg
44// Andy Goodrich: added $Log command so that CVS comments are reproduced in
45// the source.
46//
47
48#include "systemc/ext/dt/fx/scfx_utils.hh"
49
50namespace sc_dt
51{
52
53void
54scfx_tc2csd(scfx_string &s, int w_prefix)
55{
56    if (w_prefix != 0) {
57        SC_ASSERT_(s[0] == '0' && s[1] == 'c' &&
58                   s[2] == 's' && s[3] == 'd', "invalid prefix");
59    }
60
61    scfx_string csd;
62
63    // copy bits from 's' into 'csd'; skip prefix, point, and exponent
64    int i = 0;
65    int j = (w_prefix != 0 ? 4 : 0);
66    while (s[j]) {
67        if (s[j] == '0' || s[j] == '1')
68            csd[i ++] = s[j];
69        else if (s[j] != '.')
70            break;
71        ++j;
72    }
73    csd[i] = '\0';
74
75    // convert 'csd' from two's complement to csd
76    --i;
77    while (i >= 0) {
78        if (csd[i] == '0') {
79            --i;
80        } else {
81            if (i > 0 && csd[i - 1] == '0') {
82                --i;
83            } else if (i == 0) {
84                csd[i--] = '-';
85            } else {
86                csd[i--] = '-';
87                while (i >= 0 && csd[i] == '1')
88                    csd[i--] = '0';
89                if (i > 0)
90                    csd[i] = '1';
91                else if (i == 0)
92                    csd[i--] = '1';
93            }
94        }
95    }
96
97    // copy bits from 'csd' back into 's'
98    i = 0;
99    j = (w_prefix != 0 ? 4 : 0);
100    while (csd[i]) {
101        if (s[j] == '.')
102            ++j;
103        s[j++] = csd[i++];
104    }
105}
106
107
108void
109scfx_csd2tc(scfx_string &csd)
110{
111    SC_ASSERT_(csd[0] == '0' && csd[1] == 'c' &&
112               csd[2] == 's' && csd[3] == 'd', "invalid prefix");
113
114    scfx_string s;
115
116    // copy bits from 'csd' into 's'; skip prefix, point, and exponent
117    int i = 0;
118    s[i++] = '0';
119    int j = 4;
120    while (csd[j]) {
121        if (csd[j] == '-' || csd[j] == '0' || csd[j] == '1')
122            s[i++] = csd[j];
123        else if (csd[j] != '.')
124            break;
125        ++j;
126    }
127    s[i] = '\0';
128
129    // convert 's' from csd to two's complement
130    int len = i;
131    i = 1;
132    while (i < len) {
133        while (i < len && s[i] != '-')
134            i++;
135        if (i < len) {
136            j = i++;
137            s[j--] = '1';
138            while (j >= 0 && s[j] == '0')
139                s[j--] = '1';
140            if (j >= 0)
141                s[j] = '0';
142        }
143    }
144
145    // copy bits from 's' back into 'csd'
146    j = csd.length();
147    csd[j + 1] = '\0';
148    while (j > 4) {
149        csd[j] = csd[j - 1];
150        --j;
151    }
152
153    i = 0;
154    j = 4;
155    while (s[i]) {
156        if (csd[j] == '.')
157            ++j;
158        csd[j++] = s[i++];
159    }
160}
161
162} // namespace sc_dt
163