strtopdd.c revision 1.2 
1/* $NetBSD: strtopdd.c,v 1.2 2008/03/21 23:13:48 christos Exp $ */
2
3/****************************************************************
4
5The author of this software is David M. Gay.
6
7Copyright (C) 1998, 2000 by Lucent Technologies
8All Rights Reserved
9
10Permission to use, copy, modify, and distribute this software and
11its documentation for any purpose and without fee is hereby
12granted, provided that the above copyright notice appear in all
13copies and that both that the copyright notice and this
14permission notice and warranty disclaimer appear in supporting
15documentation, and that the name of Lucent or any of its entities
16not be used in advertising or publicity pertaining to
17distribution of the software without specific, written prior
18permission.
19
20LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
21INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
22IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
23SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
24WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
25IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
26ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
27THIS SOFTWARE.
28
29****************************************************************/
30
31/* Please send bug reports to David M. Gay (dmg at acm dot org,
32 * with " at " changed at "@" and " dot " changed to ".").	*/
33
34#include "gdtoaimp.h"
35
36 int
37#ifdef KR_headers
38strtopdd(s, sp, dd) CONST char *s; char **sp; double *dd;
39#else
40strtopdd(CONST char *s, char **sp, double *dd)
41#endif
42{
43#ifdef Sudden_Underflow
44	static FPI fpi = { 106, 1-1023, 2046-1023-106+1, 1, 1 };
45#else
46	static FPI fpi = { 106, 1-1023-53+1, 2046-1023-106+1, 1, 0 };
47#endif
48	ULong bits[4];
49	Long exp;
50	int i, j, rv;
51	typedef union {
52		double d[2];
53		ULong L[4];
54		} U;
55	U *u;
56
57	rv = strtodg(s, sp, &fpi, &exp, bits);
58	if (rv == STRTOG_NoMemory)
59		return rv;
60	u = (U*)dd;
61	switch(rv & STRTOG_Retmask) {
62	  case STRTOG_NoNumber:
63	  case STRTOG_Zero:
64		u->d[0] = u->d[1] = 0.;
65		break;
66
67	  case STRTOG_Normal:
68		u->L[_1] = (bits[1] >> 21 | bits[2] << 11) & 0xffffffffL;
69		u->L[_0] = bits[2] >> 21 | bits[3] << 11 & 0xfffff
70			  | exp + 0x3ff + 105 << 20;
71		exp += 0x3ff + 52;
72		if (bits[1] &= 0x1fffff) {
73			i = hi0bits(bits[1]) - 11;
74			if (i >= exp) {
75				i = exp - 1;
76				exp = 0;
77				}
78			else
79				exp -= i;
80			if (i > 0) {
81				bits[1] = bits[1] << i | bits[0] >> 32-i;
82				bits[0] = bits[0] << i & 0xffffffffL;
83				}
84			}
85		else if (bits[0]) {
86			i = hi0bits(bits[0]) + 21;
87			if (i >= exp) {
88				i = exp - 1;
89				exp = 0;
90				}
91			else
92				exp -= i;
93			if (i < 32) {
94				bits[1] = bits[0] >> 32 - i;
95				bits[0] = bits[0] << i & 0xffffffffL;
96				}
97			else {
98				bits[1] = bits[0] << i - 32;
99				bits[0] = 0;
100				}
101			}
102		else {
103			u->L[2] = u->L[3] = 0;
104			break;
105			}
106		u->L[2+_1] = bits[0];
107		u->L[2+_0] = bits[1] & 0xfffff | exp << 20;
108		break;
109
110	  case STRTOG_Denormal:
111		if (bits[3])
112			goto nearly_normal;
113		if (bits[2])
114			goto partly_normal;
115		if (bits[1] & 0xffe00000)
116			goto hardly_normal;
117		/* completely denormal */
118		u->L[2] = u->L[3] = 0;
119		u->L[_1] = bits[0];
120		u->L[_0] = bits[1];
121		break;
122
123	  nearly_normal:
124		i = hi0bits(bits[3]) - 11;	/* i >= 12 */
125		j = 32 - i;
126		u->L[_0] = (bits[3] << i | bits[2] >> j) & 0xfffff
127			| 65 - i << 20;
128		u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
129		u->L[2+_0] = bits[1] & (1L << j) - 1;
130		u->L[2+_1] = bits[0];
131		break;
132
133	  partly_normal:
134		i = hi0bits(bits[2]) - 11;
135		if (i < 0) {
136			j = -i;
137			i += 32;
138			u->L[_0] = bits[2] >> j & 0xfffff | (33 + j) << 20;
139			u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
140			u->L[2+_0] = bits[1] & (1L << j) - 1;
141			u->L[2+_1] = bits[0];
142			break;
143			}
144		if (i == 0) {
145			u->L[_0] = bits[2] & 0xfffff | 33 << 20;
146			u->L[_1] = bits[1];
147			u->L[2+_0] = 0;
148			u->L[2+_1] = bits[0];
149			break;
150			}
151		j = 32 - i;
152		u->L[_0] = (bits[2] << i | bits[1] >> j) & 0xfffff
153				| j + 1 << 20;
154		u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
155		u->L[2+_0] = 0;
156		u->L[2+_1] = bits[0] & (1L << j) - 1;
157		break;
158
159	  hardly_normal:
160		j = 11 - hi0bits(bits[1]);
161		i = 32 - j;
162		u->L[_0] = bits[1] >> j & 0xfffff | j + 1 << 20;
163		u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
164		u->L[2+_0] = 0;
165		u->L[2+_1] = bits[0] & (1L << j) - 1;
166		break;
167
168	  case STRTOG_Infinite:
169		u->L[_0] = u->L[2+_0] = 0x7ff00000;
170		u->L[_1] = u->L[2+_1] = 0;
171		break;
172
173	  case STRTOG_NaN:
174		u->L[0] = u->L[2] = d_QNAN0;
175		u->L[1] = u->L[3] = d_QNAN1;
176	  }
177	if (rv & STRTOG_Neg) {
178		u->L[  _0] |= 0x80000000L;
179		u->L[2+_0] |= 0x80000000L;
180		}
181	return rv;
182	}
183