1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
|
/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License (the "License").
* You may not use this file except in compliance with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2011 Nexenta Systems, Inc. All rights reserved.
*/
/*
* Copyright 2006 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma weak nexttowardf = __nexttowardf
#include "libm.h"
static union {
unsigned i;
float f;
} C[] = {
0x00800000,
0x7f000000,
0x7fffffff
};
#define tiny C[0].f
#define huge C[1].f
#define qnan C[2].f
#if defined(__sparc)
enum fcc_type {
fcc_equal = 0,
fcc_less = 1,
fcc_greater = 2,
fcc_unordered = 3
};
#ifdef __sparcv9
#define _Q_cmp _Qp_cmp
#endif
extern enum fcc_type _Q_cmp(const long double *, const long double *);
float
__nexttowardf(float x, long double y) {
union {
unsigned i;
float f;
} xx;
union {
unsigned i[4];
long double q;
} yy;
long double lx;
unsigned hx;
volatile float dummy;
enum fcc_type rel;
/*
* It would be somewhat more efficient to check for NaN and
* zero operands before converting x to long double and then
* to code the comparison in line rather than calling _Q_cmp.
* However, since this code probably won't get used much,
* I'm opting in favor of simplicity instead.
*/
lx = xx.f = x;
hx = xx.i & ~0x80000000;
/* check for each of four possible orderings */
rel = _Q_cmp(&lx, &y);
if (rel == fcc_unordered)
return (qnan);
if (rel == fcc_equal) {
if (hx == 0) { /* x is zero; return zero with y's sign */
yy.q = y;
xx.i = yy.i[0];
return (xx.f);
}
return (x);
}
if (rel == fcc_less) {
if (hx == 0) /* x is zero */
xx.i = 0x00000001;
else if ((int) xx.i >= 0) /* x is positive */
xx.i++;
else
xx.i--;
} else {
if (hx == 0) /* x is zero */
xx.i = 0x80000001;
else if ((int) xx.i >= 0) /* x is positive */
xx.i--;
else
xx.i++;
}
/* raise exceptions as needed */
hx = xx.i & ~0x80000000;
if (hx == 0x7f800000) {
dummy = huge;
dummy *= huge;
} else if (hx < 0x00800000) {
dummy = tiny;
dummy *= tiny;
}
return (xx.f);
}
#elif defined(__x86)
float
__nexttowardf(float x, long double y) {
union {
unsigned i;
float f;
} xx;
unsigned hx;
long double lx;
volatile float dummy;
lx = xx.f = x;
hx = xx.i & ~0x80000000;
/* check for each of four possible orderings */
if (isunordered(lx, y))
return ((float) (lx + y));
if (lx == y)
return ((float) y);
if (lx < y) {
if (hx == 0) /* x is zero */
xx.i = 0x00000001;
else if ((int) xx.i >= 0) /* x is positive */
xx.i++;
else
xx.i--;
} else {
if (hx == 0) /* x is zero */
xx.i = 0x80000001;
else if ((int) xx.i >= 0) /* x is positive */
xx.i--;
else
xx.i++;
}
/* raise exceptions as needed */
hx = xx.i & ~0x80000000;
if (hx == 0x7f800000) {
dummy = huge;
dummy *= huge;
} else if (hx < 0x00800000) {
dummy = tiny;
dummy *= tiny;
}
return (xx.f);
}
#else
#error Unknown architecture
#endif
|
