1 /* Test of splitting a 'long double' into fraction and mantissa.
2 Copyright (C) 2007 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 2, or (at your option)
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, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
18 /* Written by Bruno Haible <bruno@clisp.org>, 2007. */
29 #include "isnanl-nolibm.h"
31 #define ASSERT(expr) \
36 fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
42 /* On MIPS IRIX machines, LDBL_MIN_EXP is -1021, but the smallest reliable
43 exponent for 'long double' is -964. Similarly, on PowerPC machines,
44 LDBL_MIN_EXP is -1021, but the smallest reliable exponent for 'long double'
45 is -968. For exponents below that, the precision may be truncated to the
46 precision used for 'double'. */
48 # define MIN_NORMAL_EXP (LDBL_MIN_EXP + 57)
49 #elif defined __ppc || defined __ppc__ || defined __powerpc || defined __powerpc__
50 # define MIN_NORMAL_EXP (LDBL_MIN_EXP + 53)
52 # define MIN_NORMAL_EXP LDBL_MIN_EXP
56 my_ldexp (long double x, int d)
70 DECL_LONG_DOUBLE_ROUNDING
72 BEGIN_LONG_DOUBLE_ROUNDING ();
78 mantissa = frexpl (x, &exp);
79 ASSERT (isnanl (mantissa));
82 { /* Positive infinity. */
86 mantissa = frexpl (x, &exp);
87 ASSERT (mantissa == x);
90 { /* Negative infinity. */
94 mantissa = frexpl (x, &exp);
95 ASSERT (mantissa == x);
98 { /* Positive zero. */
100 long double mantissa;
102 mantissa = frexpl (x, &exp);
104 ASSERT (mantissa == x);
105 ASSERT (!signbit (mantissa));
108 { /* Negative zero. */
110 long double mantissa;
112 mantissa = frexpl (x, &exp);
114 ASSERT (mantissa == x);
115 ASSERT (signbit (mantissa));
118 for (i = 1, x = 1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
121 long double mantissa = frexpl (x, &exp);
123 ASSERT (mantissa == 0.5L);
125 for (i = 1, x = 1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
128 long double mantissa = frexpl (x, &exp);
130 ASSERT (mantissa == 0.5L);
132 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
135 long double mantissa = frexpl (x, &exp);
137 ASSERT (mantissa == 0.5L);
140 for (i = 1, x = -1.0L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
143 long double mantissa = frexpl (x, &exp);
145 ASSERT (mantissa == -0.5L);
147 for (i = 1, x = -1.0L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
150 long double mantissa = frexpl (x, &exp);
152 ASSERT (mantissa == -0.5L);
154 for (; i >= LDBL_MIN_EXP - 100 && x < 0.0L; i--, x *= 0.5L)
157 long double mantissa = frexpl (x, &exp);
159 ASSERT (mantissa == -0.5L);
162 for (i = 1, x = 1.01L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
165 long double mantissa = frexpl (x, &exp);
167 ASSERT (mantissa == 0.505L);
169 for (i = 1, x = 1.01L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
172 long double mantissa = frexpl (x, &exp);
174 ASSERT (mantissa == 0.505L);
176 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
179 long double mantissa = frexpl (x, &exp);
181 ASSERT (mantissa >= 0.5L);
182 ASSERT (mantissa < 1.0L);
183 ASSERT (mantissa == my_ldexp (x, - exp));
186 for (i = 1, x = 1.73205L; i <= LDBL_MAX_EXP; i++, x *= 2.0L)
189 long double mantissa = frexpl (x, &exp);
191 ASSERT (mantissa == 0.866025L);
193 for (i = 1, x = 1.73205L; i >= MIN_NORMAL_EXP; i--, x *= 0.5L)
196 long double mantissa = frexpl (x, &exp);
198 ASSERT (mantissa == 0.866025L);
200 for (; i >= LDBL_MIN_EXP - 100 && x > 0.0L; i--, x *= 0.5L)
203 long double mantissa = frexpl (x, &exp);
204 ASSERT (exp == i || exp == i + 1);
205 ASSERT (mantissa >= 0.5L);
206 ASSERT (mantissa < 1.0L);
207 ASSERT (mantissa == my_ldexp (x, - exp));