strtodnrp.c revision 1.2 
1/* $NetBSD: strtodnrp.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) 2004 by David M. Gay.
8All Rights Reserved
9Based on material in the rest of /netlib/fp/gdota.tar.gz,
10which is copyright (C) 1998, 2000 by Lucent Technologies.
11
12Permission to use, copy, modify, and distribute this software and
13its documentation for any purpose and without fee is hereby
14granted, provided that the above copyright notice appear in all
15copies and that both that the copyright notice and this
16permission notice and warranty disclaimer appear in supporting
17documentation, and that the name of Lucent or any of its entities
18not be used in advertising or publicity pertaining to
19distribution of the software without specific, written prior
20permission.
21
22LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
23INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
24IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
25SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
26WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
27IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
28ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
29THIS SOFTWARE.
30
31****************************************************************/
32
33/* This is a variant of strtod that works on Intel ia32 systems */
34/* with the default extended-precision arithmetic -- it does not */
35/* require setting the precision control to 53 bits.  */
36
37/* Please send bug reports to David M. Gay (dmg at acm dot org,
38 * with " at " changed at "@" and " dot " changed to ".").	*/
39
40#include "gdtoaimp.h"
41
42 double
43#ifdef KR_headers
44strtod(s, sp) CONST char *s; char **sp;
45#else
46strtod(CONST char *s, char **sp)
47#endif
48{
49	static FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, 1, SI };
50	ULong bits[2];
51	Long exp;
52	int k;
53	union { ULong L[2]; double d; } u;
54
55	k = strtodg(s, sp, &fpi, &exp, bits);
56	if (k == STRTOG_NoMemory) {
57		errno = ERANGE;
58		u.L[0] = Big0;
59		u.L[1] = Big1;
60		return u.d;
61	}
62	switch(k & STRTOG_Retmask) {
63	  case STRTOG_NoNumber:
64	  case STRTOG_Zero:
65		u.L[0] = u.L[1] = 0;
66		break;
67
68	  case STRTOG_Normal:
69		u.L[_1] = bits[0];
70		u.L[_0] = (bits[1] & ~0x100000) | ((exp + 0x3ff + 52) << 20);
71		break;
72
73	  case STRTOG_Denormal:
74		u.L[_1] = bits[0];
75		u.L[_0] = bits[1];
76		break;
77
78	  case STRTOG_Infinite:
79		u.L[_0] = 0x7ff00000;
80		u.L[_1] = 0;
81		break;
82
83	  case STRTOG_NaN:
84		u.L[0] = d_QNAN0;
85		u.L[1] = d_QNAN1;
86		break;
87
88	  case STRTOG_NaNbits:
89		u.L[_0] = 0x7ff00000 | bits[1];
90		u.L[_1] = bits[0];
91	  }
92	if (k & STRTOG_Neg)
93		u.L[_0] |= 0x80000000L;
94	return u.d;
95	}
96