strtopdd.c revision 1.1 
1/* $NetBSD: strtopdd.c,v 1.1 2006/01/25 15:18:53 kleink 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	u = (U*)dd;
59	switch(rv & STRTOG_Retmask) {
60	  case STRTOG_NoNumber:
61	  case STRTOG_Zero:
62		u->d[0] = u->d[1] = 0.;
63		break;
64
65	  case STRTOG_Normal:
66		u->L[_1] = (bits[1] >> 21 | bits[2] << 11) & 0xffffffffL;
67		u->L[_0] = bits[2] >> 21 | bits[3] << 11 & 0xfffff
68			  | exp + 0x3ff + 105 << 20;
69		exp += 0x3ff + 52;
70		if (bits[1] &= 0x1fffff) {
71			i = hi0bits(bits[1]) - 11;
72			if (i >= exp) {
73				i = exp - 1;
74				exp = 0;
75				}
76			else
77				exp -= i;
78			if (i > 0) {
79				bits[1] = bits[1] << i | bits[0] >> 32-i;
80				bits[0] = bits[0] << i & 0xffffffffL;
81				}
82			}
83		else if (bits[0]) {
84			i = hi0bits(bits[0]) + 21;
85			if (i >= exp) {
86				i = exp - 1;
87				exp = 0;
88				}
89			else
90				exp -= i;
91			if (i < 32) {
92				bits[1] = bits[0] >> 32 - i;
93				bits[0] = bits[0] << i & 0xffffffffL;
94				}
95			else {
96				bits[1] = bits[0] << i - 32;
97				bits[0] = 0;
98				}
99			}
100		else {
101			u->L[2] = u->L[3] = 0;
102			break;
103			}
104		u->L[2+_1] = bits[0];
105		u->L[2+_0] = bits[1] & 0xfffff | exp << 20;
106		break;
107
108	  case STRTOG_Denormal:
109		if (bits[3])
110			goto nearly_normal;
111		if (bits[2])
112			goto partly_normal;
113		if (bits[1] & 0xffe00000)
114			goto hardly_normal;
115		/* completely denormal */
116		u->L[2] = u->L[3] = 0;
117		u->L[_1] = bits[0];
118		u->L[_0] = bits[1];
119		break;
120
121	  nearly_normal:
122		i = hi0bits(bits[3]) - 11;	/* i >= 12 */
123		j = 32 - i;
124		u->L[_0] = (bits[3] << i | bits[2] >> j) & 0xfffff
125			| 65 - i << 20;
126		u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
127		u->L[2+_0] = bits[1] & (1L << j) - 1;
128		u->L[2+_1] = bits[0];
129		break;
130
131	  partly_normal:
132		i = hi0bits(bits[2]) - 11;
133		if (i < 0) {
134			j = -i;
135			i += 32;
136			u->L[_0] = bits[2] >> j & 0xfffff | (33 + j) << 20;
137			u->L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
138			u->L[2+_0] = bits[1] & (1L << j) - 1;
139			u->L[2+_1] = bits[0];
140			break;
141			}
142		if (i == 0) {
143			u->L[_0] = bits[2] & 0xfffff | 33 << 20;
144			u->L[_1] = bits[1];
145			u->L[2+_0] = 0;
146			u->L[2+_1] = bits[0];
147			break;
148			}
149		j = 32 - i;
150		u->L[_0] = (bits[2] << i | bits[1] >> j) & 0xfffff
151				| j + 1 << 20;
152		u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
153		u->L[2+_0] = 0;
154		u->L[2+_1] = bits[0] & (1L << j) - 1;
155		break;
156
157	  hardly_normal:
158		j = 11 - hi0bits(bits[1]);
159		i = 32 - j;
160		u->L[_0] = bits[1] >> j & 0xfffff | j + 1 << 20;
161		u->L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
162		u->L[2+_0] = 0;
163		u->L[2+_1] = bits[0] & (1L << j) - 1;
164		break;
165
166	  case STRTOG_Infinite:
167		u->L[_0] = u->L[2+_0] = 0x7ff00000;
168		u->L[_1] = u->L[2+_1] = 0;
169		break;
170
171	  case STRTOG_NaN:
172		u->L[0] = u->L[2] = d_QNAN0;
173		u->L[1] = u->L[3] = d_QNAN1;
174	  }
175	if (rv & STRTOG_Neg) {
176		u->L[  _0] |= 0x80000000L;
177		u->L[2+_0] |= 0x80000000L;
178		}
179	return rv;
180	}
181