1 /* Test of splitting a 'long double' into fraction and mantissa.
2 Copyright (C) 2007-2008 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 long double minus_zero = -LDBL_MIN * LDBL_MIN;
65 my_ldexp (long double x, int d)
79 DECL_LONG_DOUBLE_ROUNDING
81 BEGIN_LONG_DOUBLE_ROUNDING ();
87 mantissa = frexpl (x, &exp);
88 ASSERT (isnanl (mantissa));
91 { /* Positive infinity. */
95 mantissa = frexpl (x, &exp);
96 ASSERT (mantissa == x);
99 { /* Negative infinity. */
101 long double mantissa;
103 mantissa = frexpl (x, &exp);
104 ASSERT (mantissa == x);
107 { /* Positive zero. */
109 long double mantissa;
111 mantissa = frexpl (x, &exp);
113 ASSERT (mantissa == x);
114 ASSERT (!signbit (mantissa));
117 { /* Negative zero. */
119 long double mantissa;
121 mantissa = frexpl (x, &exp);
123 ASSERT (mantissa == x);
124 ASSERT (signbit (mantissa));
127 for (i = 1, x = 1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
130 long double mantissa = frexpl (x, &exp);
132 ASSERT (mantissa == 0.5L);
134 for (i = 1, x = 1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
137 long double mantissa = frexpl (x, &exp);
139 ASSERT (mantissa == 0.5L);
141 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
144 long double mantissa = frexpl (x, &exp);
146 ASSERT (mantissa == 0.5L);
149 for (i = 1, x = -1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
152 long double mantissa = frexpl (x, &exp);
154 ASSERT (mantissa == -0.5L);
156 for (i = 1, x = -1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
159 long double mantissa = frexpl (x, &exp);
161 ASSERT (mantissa == -0.5L);
163 for (; i >= LDBL_MIN_EXP - 100 && x < 0.0L; i--, x *= 0.5L)
166 long double mantissa = frexpl (x, &exp);
168 ASSERT (mantissa == -0.5L);
171 for (i = 1, x = 1.01L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
174 long double mantissa = frexpl (x, &exp);
176 ASSERT (mantissa == 0.505L);
178 for (i = 1, x = 1.01L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
181 long double mantissa = frexpl (x, &exp);
183 ASSERT (mantissa == 0.505L);
185 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
188 long double mantissa = frexpl (x, &exp);
190 ASSERT (mantissa >= 0.5L);
191 ASSERT (mantissa < 1.0L);
192 ASSERT (mantissa == my_ldexp (x, - exp));
195 for (i = 1, x = 1.73205L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
198 long double mantissa = frexpl (x, &exp);
200 ASSERT (mantissa == 0.866025L);
202 for (i = 1, x = 1.73205L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
205 long double mantissa = frexpl (x, &exp);
207 ASSERT (mantissa == 0.866025L);
209 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
212 long double mantissa = frexpl (x, &exp);
213 ASSERT (exp == i || exp == i + 1);
214 ASSERT (mantissa >= 0.5L);
215 ASSERT (mantissa < 1.0L);
216 ASSERT (mantissa == my_ldexp (x, - exp));