strtopdd.c revision 165743 
1/****************************************************************
2
3The author of this software is David M. Gay.
4
5Copyright (C) 1998, 2000 by Lucent Technologies
6All Rights Reserved
7
8Permission to use, copy, modify, and distribute this software and
9its documentation for any purpose and without fee is hereby
10granted, provided that the above copyright notice appear in all
11copies and that both that the copyright notice and this
12permission notice and warranty disclaimer appear in supporting
13documentation, and that the name of Lucent or any of its entities
14not be used in advertising or publicity pertaining to
15distribution of the software without specific, written prior
16permission.
17
18LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
20IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
21SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
22WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
23IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
24ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
25THIS SOFTWARE.
26
27****************************************************************/
28
29/* Please send bug reports to David M. Gay (dmg at acm dot org,
30 * with " at " changed at "@" and " dot " changed to ".").	*/
31
32#include "gdtoaimp.h"
33
34 int
35#ifdef KR_headers
36strtopdd(s, sp, dd) CONST char *s; char **sp; double *dd;
37#else
38strtopdd(CONST char *s, char **sp, double *dd)
39#endif
40{
41#ifdef Sudden_Underflow
42	static FPI fpi = { 106, 1-1023, 2046-1023-106+1, 1, 1 };
43#else
44	static FPI fpi = { 106, 1-1023-53+1, 2046-1023-106+1, 1, 0 };
45#endif
46	ULong bits[4];
47	Long exp;
48	int i, j, rv;
49	typedef union {
50		double d[2];
51		ULong L[4];
52		} U;
53	U *u;
54
55	rv = strtodg(s, sp, &fpi, &exp, bits);
56	u = (U*)dd;
57	switch(rv & STRTOG_Retmask) {
58	  case STRTOG_NoNumber:
59	  case STRTOG_Zero:
60		u->d[0] = u->d[1] = 0.;
61		break;
62
63	  case STRTOG_Normal:
64		u->L[_1] = (bits[1] >> 21 | bits[2] << 11) & 0xffffffffL;
65		u->L[_0] = bits[2] >> 21 | bits[3] << 11 & 0xfffff
66			  | exp + 0x3ff + 105 << 20;
67		exp += 0x3ff + 52;
68		if (bits[1] &= 0x1fffff) {
69			i = hi0bits(bits[1]) - 11;
70			if (i >= exp) {
71				i = exp - 1;
72				exp = 0;
73				}
74			else
75				exp -= i;
76			if (i > 0) {
77				bits[1] = bits[1] << i | bits[0] >> 32-i;
78				bits[0] = bits[0] << i & 0xffffffffL;
79				}
80			}
81		else if (bits[0]) {
82			i = hi0bits(bits[0]) + 21;
83			if (i >= exp) {
84				i = exp - 1;
85				exp = 0;
86				}
87			else
88				exp -= i;
89			if (i < 32) {
90				bits[1] = bits[0] >> 32 - i;
91				bits[0] = bits[0] << i & 0xffffffffL;
92				}
93			else {
94				bits[1] = bits[0] << i - 32;
95				bits[0] = 0;
96				}
97			}
98		else {
99			u->L[2] = u->L[3] = 0;
100			break;
101			}
102		u->L[2+_1] = bits[0];
103		u->L[2+_0] = bits[1] & 0xfffff | exp << 20;
104		break;
105
106	  case STRTOG_Denormal:
107		if (bits[3])
108			goto nearly_normal;
109		if (bits[2])
110			goto partly_normal;
111		if (bits[1] & 0xffe00000)
112			goto hardly_normal;
113		/* completely denormal */
114		u->L[2] = u->L[3] = 0;
115		u->L[_1] = bits[0];
116		u->L[_0] = bits[1];
117		break;
118
119	  nearly_normal:
120		i = hi0bits(bits[3]) - 11;	/* i >= 12 */
121		j = 32 - i;
122		u->L[_0] = (bits[3] << i | bits[2] >> j) & 0xfffff
123			| 65 - i << 20;
124		u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
125		u->L[2+_0] = bits[1] & (1L << j) - 1;
126		u->L[2+_1] = bits[0];
127		break;
128
129	  partly_normal:
130		i = hi0bits(bits[2]) - 11;
131		if (i < 0) {
132			j = -i;
133			i += 32;
134			u->L[_0] = bits[2] >> j & 0xfffff | (33 + j) << 20;
135			u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
136			u->L[2+_0] = bits[1] & (1L << j) - 1;
137			u->L[2+_1] = bits[0];
138			break;
139			}
140		if (i == 0) {
141			u->L[_0] = bits[2] & 0xfffff | 33 << 20;
142			u->L[_1] = bits[1];
143			u->L[2+_0] = 0;
144			u->L[2+_1] = bits[0];
145			break;
146			}
147		j = 32 - i;
148		u->L[_0] = (bits[2] << i | bits[1] >> j) & 0xfffff
149				| j + 1 << 20;
150		u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
151		u->L[2+_0] = 0;
152		u->L[2+_1] = bits[0] & (1L << j) - 1;
153		break;
154
155	  hardly_normal:
156		j = 11 - hi0bits(bits[1]);
157		i = 32 - j;
158		u->L[_0] = bits[1] >> j & 0xfffff | j + 1 << 20;
159		u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
160		u->L[2+_0] = 0;
161		u->L[2+_1] = bits[0] & (1L << j) - 1;
162		break;
163
164	  case STRTOG_Infinite:
165		u->L[_0] = u->L[2+_0] = 0x7ff00000;
166		u->L[_1] = u->L[2+_1] = 0;
167		break;
168
169	  case STRTOG_NaN:
170		u->L[0] = u->L[2] = d_QNAN0;
171		u->L[1] = u->L[3] = d_QNAN1;
172	  }
173	if (rv & STRTOG_Neg) {
174		u->L[  _0] |= 0x80000000L;
175		u->L[2+_0] |= 0x80000000L;
176		}
177	return rv;
178	}
179