1/* $NetBSD: strtodI.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 static double
37#ifdef KR_headers
38ulpdown(d) U *d;
39#else
40ulpdown(U *d)
41#endif
42{
43	double u;
44	ULong *L = d->L;
45
46	u = ulp(d);
47	if (!(L[_1] | (L[_0] & 0xfffff))
48	 && (L[_0] & 0x7ff00000) > 0x00100000)
49		u *= 0.5;
50	return u;
51	}
52
53 int
54#ifdef KR_headers
55strtodI(s, sp, dd) CONST char *s; char **sp; double *dd;
56#else
57strtodI(CONST char *s, char **sp, double *dd)
58#endif
59{
60	static FPI fpi = { 53, 1-1023-53+1, 2046-1023-53+1, 1, SI };
61	ULong bits[2], sign;
62	Long exp;
63	int j, k;
64	U *u;
65
66	k = strtodg(s, sp, &fpi, &exp, bits);
67	if (k == STRTOG_NoMemory)
68		return k;
69	u = (U*)dd;
70	sign = k & STRTOG_Neg ? 0x80000000L : 0;
71	switch(k & STRTOG_Retmask) {
72	  case STRTOG_NoNumber:
73		dval(&u[0]) = dval(&u[1]) = 0.;
74		break;
75
76	  case STRTOG_Zero:
77		dval(&u[0]) = dval(&u[1]) = 0.;
78#ifdef Sudden_Underflow
79		if (k & STRTOG_Inexact) {
80			if (sign)
81				word0(&u[0]) = 0x80100000L;
82			else
83				word0(&u[1]) = 0x100000L;
84			}
85		break;
86#else
87		goto contain;
88#endif
89
90	  case STRTOG_Denormal:
91		word1(&u[0]) = bits[0];
92		word0(&u[0]) = bits[1];
93		goto contain;
94
95	  case STRTOG_Normal:
96		word1(&u[0]) = bits[0];
97		word0(&u[0]) = (bits[1] & ~0x100000) | ((exp + 0x3ff + 52) << 20);
98	  contain:
99		j = k & STRTOG_Inexact;
100		if (sign) {
101			word0(&u[0]) |= sign;
102			j = STRTOG_Inexact - j;
103			}
104		switch(j) {
105		  case STRTOG_Inexlo:
106#ifdef Sudden_Underflow
107			if ((u->L[_0] & 0x7ff00000) < 0x3500000) {
108				word0(&u[1]) = word0(&u[0]) + 0x3500000;
109				word1(&u[1]) = word1(&u[0]);
110				dval(&u[1]) += ulp(&u[1]);
111				word0(&u[1]) -= 0x3500000;
112				if (!(word0(&u[1]) & 0x7ff00000)) {
113					word0(&u[1]) = sign;
114					word1(&u[1]) = 0;
115					}
116				}
117			else
118#endif
119			dval(&u[1]) = dval(&u[0]) + ulp(&u[0]);
120			break;
121		  case STRTOG_Inexhi:
122			dval(&u[1]) = dval(&u[0]);
123#ifdef Sudden_Underflow
124			if ((word0(&u[0]) & 0x7ff00000) < 0x3500000) {
125				word0(&u[0]) += 0x3500000;
126				dval(&u[0]) -= ulpdown(u);
127				word0(&u[0]) -= 0x3500000;
128				if (!(word0(&u[0]) & 0x7ff00000)) {
129					word0(&u[0]) = sign;
130					word1(&u[0]) = 0;
131					}
132				}
133			else
134#endif
135			dval(&u[0]) -= ulpdown(u);
136			break;
137		  default:
138			dval(&u[1]) = dval(&u[0]);
139		  }
140		break;
141
142	  case STRTOG_Infinite:
143		word0(&u[0]) = word0(&u[1]) = sign | 0x7ff00000;
144		word1(&u[0]) = word1(&u[1]) = 0;
145		if (k & STRTOG_Inexact) {
146			if (sign) {
147				word0(&u[1]) = 0xffefffffL;
148				word1(&u[1]) = 0xffffffffL;
149				}
150			else {
151				word0(&u[0]) = 0x7fefffffL;
152				word1(&u[0]) = 0xffffffffL;
153				}
154			}
155		break;
156
157	  case STRTOG_NaN:
158		u->L[0] = (u+1)->L[0] = d_QNAN0;
159		u->L[1] = (u+1)->L[1] = d_QNAN1;
160		break;
161
162	  case STRTOG_NaNbits:
163		word0(&u[0]) = word0(&u[1]) = 0x7ff00000 | sign | bits[1];
164		word1(&u[0]) = word1(&u[1]) = bits[0];
165	  }
166	return k;
167	}
168