1 /* Test of splitting a 'long double' into fraction and mantissa.
2 Copyright (C) 2007-2009 Free Software Foundation, Inc.
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 3 of the License, or
7 (at your option) any later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
17 /* Written by Bruno Haible <bruno@clisp.org>, 2007. */
28 #include "isnanl-nolibm.h"
30 /* Avoid some warnings from "gcc -Wshadow".
31 This file doesn't use the exp() function. */
35 #define ASSERT(expr) \
40 fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
47 /* On MIPS IRIX machines, LDBL_MIN_EXP is -1021, but the smallest reliable
48 exponent for 'long double' is -964. Similarly, on PowerPC machines,
49 LDBL_MIN_EXP is -1021, but the smallest reliable exponent for 'long double'
50 is -968. For exponents below that, the precision may be truncated to the
51 precision used for 'double'. */
53 # define MIN_NORMAL_EXP (LDBL_MIN_EXP + 57)
54 #elif defined __ppc || defined __ppc__ || defined __powerpc || defined __powerpc__
55 # define MIN_NORMAL_EXP (LDBL_MIN_EXP + 53)
57 # define MIN_NORMAL_EXP LDBL_MIN_EXP
60 /* On HP-UX 10.20, negating 0.0L does not yield -0.0L.
61 So we use minus_zero instead.
62 IRIX cc can't put -0.0L into .data, but can compute at runtime.
63 Note that the expression -LDBL_MIN * LDBL_MIN does not work on other
64 platforms, such as when cross-compiling to PowerPC on MacOS X 10.5. */
65 #if defined __hpux || defined __sgi
67 compute_minus_zero (void)
69 return -LDBL_MIN * LDBL_MIN;
71 # define minus_zero compute_minus_zero ()
73 long double minus_zero = -0.0L;
77 my_ldexp (long double x, int d)
91 DECL_LONG_DOUBLE_ROUNDING
93 BEGIN_LONG_DOUBLE_ROUNDING ();
99 mantissa = frexpl (x, &exp);
100 ASSERT (isnanl (mantissa));
103 { /* Positive infinity. */
105 long double mantissa;
107 mantissa = frexpl (x, &exp);
108 ASSERT (mantissa == x);
111 { /* Negative infinity. */
113 long double mantissa;
115 mantissa = frexpl (x, &exp);
116 ASSERT (mantissa == x);
119 { /* Positive zero. */
121 long double mantissa;
123 mantissa = frexpl (x, &exp);
125 ASSERT (mantissa == x);
126 ASSERT (!signbit (mantissa));
129 { /* Negative zero. */
131 long double mantissa;
133 mantissa = frexpl (x, &exp);
135 ASSERT (mantissa == x);
136 ASSERT (signbit (mantissa));
139 for (i = 1, x = 1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
142 long double mantissa = frexpl (x, &exp);
144 ASSERT (mantissa == 0.5L);
146 for (i = 1, x = 1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
149 long double mantissa = frexpl (x, &exp);
151 ASSERT (mantissa == 0.5L);
153 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
156 long double mantissa = frexpl (x, &exp);
158 ASSERT (mantissa == 0.5L);
161 for (i = 1, x = -1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
164 long double mantissa = frexpl (x, &exp);
166 ASSERT (mantissa == -0.5L);
168 for (i = 1, x = -1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
171 long double mantissa = frexpl (x, &exp);
173 ASSERT (mantissa == -0.5L);
175 for (; i >= LDBL_MIN_EXP - 100 && x < 0.0L; i--, x *= 0.5L)
178 long double mantissa = frexpl (x, &exp);
180 ASSERT (mantissa == -0.5L);
183 for (i = 1, x = 1.01L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
186 long double mantissa = frexpl (x, &exp);
188 ASSERT (mantissa == 0.505L);
190 for (i = 1, x = 1.01L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
193 long double mantissa = frexpl (x, &exp);
195 ASSERT (mantissa == 0.505L);
197 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
200 long double mantissa = frexpl (x, &exp);
202 ASSERT (mantissa >= 0.5L);
203 ASSERT (mantissa < 1.0L);
204 ASSERT (mantissa == my_ldexp (x, - exp));
207 for (i = 1, x = 1.73205L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
210 long double mantissa = frexpl (x, &exp);
212 ASSERT (mantissa == 0.866025L);
214 for (i = 1, x = 1.73205L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
217 long double mantissa = frexpl (x, &exp);
219 ASSERT (mantissa == 0.866025L);
221 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
224 long double mantissa = frexpl (x, &exp);
225 ASSERT (exp == i || exp == i + 1);
226 ASSERT (mantissa >= 0.5L);
227 ASSERT (mantissa < 1.0L);
228 ASSERT (mantissa == my_ldexp (x, - exp));