1 /* Test of exp2*() function family.
2 Copyright (C) 2012 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/>. */
22 const DOUBLE TWO_MANT_DIG =
23 /* Assume MANT_DIG <= 5 * 31.
25 n = floor(n/5) + floor((n+1)/5) + ... + floor((n+4)/5). */
26 (DOUBLE) (1U << ((MANT_DIG - 1) / 5))
27 * (DOUBLE) (1U << ((MANT_DIG - 1 + 1) / 5))
28 * (DOUBLE) (1U << ((MANT_DIG - 1 + 2) / 5))
29 * (DOUBLE) (1U << ((MANT_DIG - 1 + 3) / 5))
30 * (DOUBLE) (1U << ((MANT_DIG - 1 + 4) / 5));
32 /* Small integral arguments. */
36 ASSERT (y == L_(1.0));
41 ASSERT (y == L_(2.0));
46 ASSERT (y == L_(4.0));
48 /* <http://sourceware.org/bugzilla/show_bug.cgi?id=13824> */
49 #if !(defined __linux__ && defined __sparc__)
53 ASSERT (y == L_(8.0));
58 ASSERT (y == L_(16.0));
64 ASSERT (y == L_(0.5));
69 ASSERT (y == L_(0.25));
72 /* Randomized tests. */
74 /* Error bound, in ulps. */
75 const DOUBLE err_bound =
76 (sizeof (DOUBLE) == sizeof (long double) ?
77 #if defined __i386__ && defined __FreeBSD__
78 /* On FreeBSD/x86 6.4, the 'long double' type really has only 53 bits of
79 precision in the compiler but 64 bits of precision at runtime. See
80 <http://lists.gnu.org/archive/html/bug-gnulib/2008-07/msg00063.html>.
81 The compiler has truncated all 'long double' literals in exp2l.c to
82 53 bits of precision. */
89 for (i = 0; i < SIZEOF (RANDOM); i++)
91 DOUBLE x = L_(16.0) * RANDOM[i]; /* 0.0 <= x <= 16.0 */
93 DOUBLE z = EXP2 (- x);
94 DOUBLE err = y * z - L_(1.0);
97 ASSERT (err > - err_bound / TWO_MANT_DIG
98 && err < err_bound / TWO_MANT_DIG);
103 /* Error bound, in ulps. */
104 const DOUBLE err_bound =
105 (sizeof (DOUBLE) == sizeof (long double) ?
106 #if defined __i386__ && defined __FreeBSD__
113 for (i = 0; i < SIZEOF (RANDOM) / 5; i++)
114 for (j = 0; j < SIZEOF (RANDOM) / 5; j++)
116 DOUBLE x = L_(32.0) * RANDOM[i] - L_(16.0); /* -16.0 <= x <= 16.0 */
117 DOUBLE y = L_(32.0) * RANDOM[j] - L_(16.0); /* -16.0 <= y <= 16.0 */
119 /* Approximately x + y + z = 0. */
120 DOUBLE err = EXP2 (x) * EXP2 (y) * EXP2 (z) - L_(1.0);
121 ASSERT (err > - err_bound / TWO_MANT_DIG
122 && err < err_bound / TWO_MANT_DIG);