xref: /freebsd/contrib/gdtoa/smisc.c (revision 2be1a816b9ff69588e55be0a84cbe2a31efc0f2f)
1 /****************************************************************
2 
3 The author of this software is David M. Gay.
4 
5 Copyright (C) 1998, 1999 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 David M. Gay (dmg at acm dot org,
30  * with " at " changed at "@" and " dot " changed to ".").	*/
31 
32 #include "gdtoaimp.h"
33 
34  Bigint *
35 s2b
36 #ifdef KR_headers
37 	(s, nd0, nd, y9) CONST char *s; int nd0, nd; ULong y9;
38 #else
39 	(CONST char *s, int nd0, int nd, ULong y9)
40 #endif
41 {
42 	Bigint *b;
43 	int i, k;
44 	Long x, y;
45 
46 	x = (nd + 8) / 9;
47 	for(k = 0, y = 1; x > y; y <<= 1, k++) ;
48 #ifdef Pack_32
49 	b = Balloc(k);
50 	b->x[0] = y9;
51 	b->wds = 1;
52 #else
53 	b = Balloc(k+1);
54 	b->x[0] = y9 & 0xffff;
55 	b->wds = (b->x[1] = y9 >> 16) ? 2 : 1;
56 #endif
57 
58 	i = 9;
59 	if (9 < nd0) {
60 		s += 9;
61 		do b = multadd(b, 10, *s++ - '0');
62 			while(++i < nd0);
63 		s++;
64 		}
65 	else
66 		s += 10;
67 	for(; i < nd; i++)
68 		b = multadd(b, 10, *s++ - '0');
69 	return b;
70 	}
71 
72  double
73 ratio
74 #ifdef KR_headers
75 	(a, b) Bigint *a, *b;
76 #else
77 	(Bigint *a, Bigint *b)
78 #endif
79 {
80 	double da, db;
81 	int k, ka, kb;
82 
83 	dval(da) = b2d(a, &ka);
84 	dval(db) = b2d(b, &kb);
85 	k = ka - kb + ULbits*(a->wds - b->wds);
86 #ifdef IBM
87 	if (k > 0) {
88 		word0(da) += (k >> 2)*Exp_msk1;
89 		if (k &= 3)
90 			dval(da) *= 1 << k;
91 		}
92 	else {
93 		k = -k;
94 		word0(db) += (k >> 2)*Exp_msk1;
95 		if (k &= 3)
96 			dval(db) *= 1 << k;
97 		}
98 #else
99 	if (k > 0)
100 		word0(da) += k*Exp_msk1;
101 	else {
102 		k = -k;
103 		word0(db) += k*Exp_msk1;
104 		}
105 #endif
106 	return dval(da) / dval(db);
107 	}
108 
109 #ifdef INFNAN_CHECK
110 
111  int
112 match
113 #ifdef KR_headers
114 	(sp, t) char **sp, *t;
115 #else
116 	(CONST char **sp, char *t)
117 #endif
118 {
119 	int c, d;
120 	CONST char *s = *sp;
121 
122 	while( (d = *t++) !=0) {
123 		if ((c = *++s) >= 'A' && c <= 'Z')
124 			c += 'a' - 'A';
125 		if (c != d)
126 			return 0;
127 		}
128 	*sp = s + 1;
129 	return 1;
130 	}
131 #endif /* INFNAN_CHECK */
132 
133  void
134 #ifdef KR_headers
135 copybits(c, n, b) ULong *c; int n; Bigint *b;
136 #else
137 copybits(ULong *c, int n, Bigint *b)
138 #endif
139 {
140 	ULong *ce, *x, *xe;
141 #ifdef Pack_16
142 	int nw, nw1;
143 #endif
144 
145 	ce = c + ((n-1) >> kshift) + 1;
146 	x = b->x;
147 #ifdef Pack_32
148 	xe = x + b->wds;
149 	while(x < xe)
150 		*c++ = *x++;
151 #else
152 	nw = b->wds;
153 	nw1 = nw & 1;
154 	for(xe = x + (nw - nw1); x < xe; x += 2)
155 		Storeinc(c, x[1], x[0]);
156 	if (nw1)
157 		*c++ = *x;
158 #endif
159 	while(c < ce)
160 		*c++ = 0;
161 	}
162 
163  ULong
164 #ifdef KR_headers
165 any_on(b, k) Bigint *b; int k;
166 #else
167 any_on(Bigint *b, int k)
168 #endif
169 {
170 	int n, nwds;
171 	ULong *x, *x0, x1, x2;
172 
173 	x = b->x;
174 	nwds = b->wds;
175 	n = k >> kshift;
176 	if (n > nwds)
177 		n = nwds;
178 	else if (n < nwds && (k &= kmask)) {
179 		x1 = x2 = x[n];
180 		x1 >>= k;
181 		x1 <<= k;
182 		if (x1 != x2)
183 			return 1;
184 		}
185 	x0 = x;
186 	x += n;
187 	while(x > x0)
188 		if (*--x)
189 			return 1;
190 	return 0;
191 	}
192