1 /*
2 (C) Copyright IBM Corp. 2009
3
4 All rights reserved.
5
6 Redistribution and use in source and binary forms, with or without
7 modification, are permitted provided that the following conditions are met:
8
9 * Redistributions of source code must retain the above copyright notice,
10 this list of conditions and the following disclaimer.
11 * Redistributions in binary form must reproduce the above copyright
12 notice, this list of conditions and the following disclaimer in the
13 documentation and/or other materials provided with the distribution.
14 * Neither the name of IBM nor the names of its contributors may be
15 used to endorse or promote products derived from this software without
16 specific prior written permission.
17
18 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
19 AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
22 LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
23 CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
24 SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
25 INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
26 CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
27 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
28 POSSIBILITY OF SUCH DAMAGE.
29 */
30
31 #include "math_config.h"
32
33 #if defined(_NEED_FLOAT_HUGE) && !defined(_HAVE_LONG_DOUBLE_MATH)
34 # if (LDBL_MANT_DIG == 53) /* 64-bit long double */
35 static const long double scale = 0x1p54;
36
37 union ldbl {
38 long double x;
39 struct {
40 # ifdef __IEEE_LITTLE_ENDIAN /* for Intel CPU */
41 __uint32_t fracl;
42 __uint32_t frach:20;
43 __uint32_t exp:11;
44 __uint32_t sign:1;
45 # endif
46 # ifdef __IEEE_BIG_ENDIAN
47 __uint32_t sign:1;
48 __uint32_t exp:11;
49 __uint32_t frach:20;
50 # ifndef ___IEEE_BYTES_LITTLE_ENDIAN
51 # else /* ARMEL without __VFP_FP__ */
52 __uint32_t frach:20;
53 __uint32_t exp:11;
54 __uint32_t sign:1;
55 # endif
56 __uint32_t fracl;
57 # endif
58 } u32;
59 };
60 # elif (LDBL_MANT_DIG == 64) /* 80-bit long double */
61 static const double scale = 0x1p65;
62
63 union ldbl {
64 long double x;
65 struct {
66 # ifdef __IEEE_LITTLE_ENDIAN /* for Intel CPU */
67 __uint32_t fracl;
68 __uint32_t frach;
69 __uint32_t exp:15;
70 __uint32_t sign:1;
71 __uint32_t pad:16;
72 # endif
73 # ifdef __IEEE_BIG_ENDIAN
74 # ifndef ___IEEE_BYTES_LITTLE_ENDIAN /* for m86k */
75 __uint32_t sign:1;
76 __uint32_t exp:15;
77 __uint32_t pad:16;
78 # else /* ARM FPA10 math copprocessor */
79 __uint32_t exp:15;
80 __uint32_t pad:16;
81 __uint32_t sign:1;
82 # endif
83 __uint32_t frach;
84 __uint32_t fracl;
85 # endif
86 } u32;
87 };
88 # elif (LDBL_MANT_DIG == 106) /* 128-bit double double */
89 static const long double scale = 0x1p107l;
90
91 #define EXP_EXTRA_BIAS 100
92
93 union ldbl {
94 long double x;
95 struct {
96 # ifdef __IEEE_LITTLE_ENDIAN
97 __uint32_t frachm;
98 __uint32_t frach:20;
99 __uint32_t exp:11;
100 __uint32_t sign:1;
101 __uint32_t fracl;
102 __uint32_t fraclm:20;
103 __uint32_t exp_extra:11;
104 __uint32_t sign_extra:1;
105 # endif
106 # ifdef __IEEE_BIG_ENDIAN
107 __uint32_t sign:1;
108 __uint32_t exp:11;
109 __uint32_t frach:20;
110 __uint32_t frachm;
111 __uint32_t sign_extra:1;
112 __uint32_t exp_extra:11;
113 __uint32_t fraclm:20;
114 __uint32_t fracl;
115 # endif
116 } u32;
117 };
118 # elif (LDBL_MANT_DIG == 113) /* 128-bit long double */
119 static const long double scale = 0x1p114l;
120
121 union ldbl {
122 long double x;
123 struct {
124 # ifdef __IEEE_LITTLE_ENDIAN
125 __uint32_t fracl;
126 __uint32_t fraclm;
127 __uint32_t frachm;
128 __uint32_t frach:16;
129 __uint32_t exp:15;
130 __uint32_t sign:1;
131 # endif
132 # ifdef __IEEE_BIG_ENDIAN
133 # ifndef ___IEEE_BYTES_LITTLE_ENDIAN
134 __uint32_t sign:1;
135 __uint32_t exp:15;
136 __uint32_t frach:16;
137 # else /* ARMEL without __VFP_FP__ */
138 __uint32_t frach:16;
139 __uint32_t exp:15;
140 __uint32_t sign:1;
141 # endif
142 __uint32_t frachm;
143 __uint32_t fraclm;
144 __uint32_t fracl;
145 # endif
146 } u32;
147 };
148 # else
149 # error Unsupported long double format.
150 # endif
151
152 static const int scale_exp = LDBL_MANT_DIG + 1;
153
154 long double
frexpl(long double x,int * eptr)155 frexpl (long double x, int *eptr)
156 {
157 union ldbl u;
158 u.x = x;
159 int e = u.u32.exp;
160 *eptr = 0;
161 if (e == (LDBL_MAX_EXP*2 - 1) || x == 0)
162 return x; /* inf,nan,0 */
163 if (e == 0) /* subnormal */
164 {
165 u.x *= (long double) scale;
166 e = u.u32.exp;
167 *eptr -= scale_exp;
168 }
169 *eptr += e - (LDBL_MAX_EXP - 2);
170 u.u32.exp = LDBL_MAX_EXP - 2; /* -1 */
171 #ifdef EXP_EXTRA_BIAS
172 if (u.u32.exp_extra != 0)
173 u.u32.exp_extra = u.u32.exp - EXP_EXTRA_BIAS;
174 #endif
175 return u.x;
176 }
177 #endif /* _NEED_FLOAT_HUGE */
178
