xref: /freebsd/contrib/gdtoa/strtordd.c (revision 2357939bc239bd5334a169b62313806178dd8f30)
1 /****************************************************************
2 
3 The author of this software is David M. Gay.
4 
5 Copyright (C) 1998, 2000 by Lucent Technologies
6 All Rights Reserved
7 
8 Permission to use, copy, modify, and distribute this software and
9 its documentation for any purpose and without fee is hereby
10 granted, provided that the above copyright notice appear in all
11 copies and that both that the copyright notice and this
12 permission notice and warranty disclaimer appear in supporting
13 documentation, and that the name of Lucent or any of its entities
14 not be used in advertising or publicity pertaining to
15 distribution of the software without specific, written prior
16 permission.
17 
18 LUCENT DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
19 INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS.
20 IN NO EVENT SHALL LUCENT OR ANY OF ITS ENTITIES BE LIABLE FOR ANY
21 SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
22 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER
23 IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
24 ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
25 THIS SOFTWARE.
26 
27 ****************************************************************/
28 
29 /* Please send bug reports to
30 	David M. Gay
31 	Bell Laboratories, Room 2C-463
32 	600 Mountain Avenue
33 	Murray Hill, NJ 07974-0636
34 	U.S.A.
35 	dmg@bell-labs.com
36  */
37 
38 #include "gdtoaimp.h"
39 
40  void
41 #ifdef KR_headers
42 ULtodd(L, bits, exp, k) ULong *L; ULong *bits; Long exp; int k;
43 #else
44 ULtodd(ULong *L, ULong *bits, Long exp, int k)
45 #endif
46 {
47 	int i, j;
48 
49 	switch(k & STRTOG_Retmask) {
50 	  case STRTOG_NoNumber:
51 	  case STRTOG_Zero:
52 		L[0] = L[1] = L[2] = L[3] = 0;
53 		break;
54 
55 	  case STRTOG_Normal:
56 		L[_1] = (bits[1] >> 21 | bits[2] << 11) & (ULong)0xffffffffL;
57 		L[_0] = bits[2] >> 21 | bits[3] << 11 & 0xfffff
58 			  | exp + 0x3ff + 105 << 20;
59 		exp += 0x3ff + 52;
60 		if (bits[1] &= 0x1fffff) {
61 			i = hi0bits(bits[1]) - 11;
62 			if (i >= exp) {
63 				i = exp - 1;
64 				exp = 0;
65 				}
66 			else
67 				exp -= i;
68 			if (i > 0) {
69 				bits[1] = bits[1] << i | bits[0] >> 32-i;
70 				bits[0] = bits[0] << i & (ULong)0xffffffffL;
71 				}
72 			}
73 		else if (bits[0]) {
74 			i = hi0bits(bits[0]) + 21;
75 			if (i >= exp) {
76 				i = exp - 1;
77 				exp = 0;
78 				}
79 			else
80 				exp -= i;
81 			if (i < 32) {
82 				bits[1] = bits[0] >> 32 - i;
83 				bits[0] = bits[0] << i & (ULong)0xffffffffL;
84 				}
85 			else {
86 				bits[1] = bits[0] << i - 32;
87 				bits[0] = 0;
88 				}
89 			}
90 		else {
91 			L[2] = L[3] = 0;
92 			break;
93 			}
94 		L[2+_1] = bits[0];
95 		L[2+_0] = bits[1] & 0xfffff | exp << 20;
96 		break;
97 
98 	  case STRTOG_Denormal:
99 		if (bits[3])
100 			goto nearly_normal;
101 		if (bits[2])
102 			goto partly_normal;
103 		if (bits[1] & 0xffe00000)
104 			goto hardly_normal;
105 		/* completely denormal */
106 		L[2] = L[3] = 0;
107 		L[_1] = bits[0];
108 		L[_0] = bits[1];
109 		break;
110 
111 	  nearly_normal:
112 		i = hi0bits(bits[3]) - 11;	/* i >= 12 */
113 		j = 32 - i;
114 		L[_0] = (bits[3] << i | bits[2] >> j) & 0xfffff
115 			| 65 - i << 20;
116 		L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
117 		L[2+_0] = bits[1] & ((ULong)1L << j) - 1;
118 		L[2+_1] = bits[0];
119 		break;
120 
121 	  partly_normal:
122 		i = hi0bits(bits[2]) - 11;
123 		if (i < 0) {
124 			j = -i;
125 			i += 32;
126 			L[_0] = bits[2] >> j & 0xfffff | (33 + j) << 20;
127 			L[_1] = (bits[2] << i | bits[1] >> j) & 0xffffffffL;
128 			L[2+_0] = bits[1] & ((ULong)1L << j) - 1;
129 			L[2+_1] = bits[0];
130 			break;
131 			}
132 		if (i == 0) {
133 			L[_0] = bits[2] & 0xfffff | 33 << 20;
134 			L[_1] = bits[1];
135 			L[2+_0] = 0;
136 			L[2+_1] = bits[0];
137 			break;
138 			}
139 		j = 32 - i;
140 		L[_0] = (bits[2] << i | bits[1] >> j) & 0xfffff
141 				| j + 1 << 20;
142 		L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
143 		L[2+_0] = 0;
144 		L[2+_1] = bits[0] & (1L << j) - 1;
145 		break;
146 
147 	  hardly_normal:
148 		j = 11 - hi0bits(bits[1]);
149 		i = 32 - j;
150 		L[_0] = bits[1] >> j & 0xfffff | j + 1 << 20;
151 		L[_1] = (bits[1] << i | bits[0] >> j) & 0xffffffffL;
152 		L[2+_0] = 0;
153 		L[2+_1] = bits[0] & ((ULong)1L << j) - 1;
154 		break;
155 
156 	  case STRTOG_Infinite:
157 		L[_0] = L[2+_0] = 0x7ff00000;
158 		L[_1] = L[2+_1] = 0;
159 		break;
160 
161 	  case STRTOG_NaN:
162 		L[_0] = L[2+_0] = 0x7fffffff;
163 		L[_1] = L[2+_1] = (ULong)-1;
164 		break;
165 
166 	  case STRTOG_NaNbits:
167 		L[_1] = (bits[1] >> 21 | bits[2] << 11) & (ULong)0xffffffffL;
168 		L[_0] = bits[2] >> 21 | bits[3] << 11
169 			  | (ULong)0x7ff00000L;
170 		L[2+_1] = bits[0];
171 		L[2+_0] = bits[1] | (ULong)0x7ff00000L;
172 	  }
173 	if (k & STRTOG_Neg) {
174 		L[_0] |= 0x80000000L;
175 		L[2+_0] |= 0x80000000L;
176 		}
177 	}
178 
179  int
180 #ifdef KR_headers
181 strtordd(s, sp, rounding, dd) CONST char *s; char **sp; int rounding; double *dd;
182 #else
183 strtordd(CONST char *s, char **sp, int rounding, double *dd)
184 #endif
185 {
186 #ifdef Sudden_Underflow
187 	static FPI fpi0 = { 106, 1-1023, 2046-1023-106+1, 1, 1 };
188 #else
189 	static FPI fpi0 = { 106, 1-1023-53+1, 2046-1023-106+1, 1, 0 };
190 #endif
191 	FPI *fpi, fpi1;
192 	ULong bits[4];
193 	Long exp;
194 	int k;
195 
196 	fpi = &fpi0;
197 	if (rounding != FPI_Round_near) {
198 		fpi1 = fpi0;
199 		fpi1.rounding = rounding;
200 		fpi = &fpi1;
201 		}
202 	k = strtodg(s, sp, fpi, &exp, bits);
203 	ULtodd((ULong*)dd, bits, exp, k);
204 	return k;
205 	}
206