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2b778ceb | 1 | /* Copyright (C) 2011-2021 Free Software Foundation, Inc. |
1004d182 UD |
2 | This file is part of the GNU C Library. |
3 | Contributed by Ulrich Drepper <drepper@gmail.com>, 2011. | |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
6 | modify it under the terms of the GNU Lesser General Public | |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
9 | ||
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
13 | Lesser General Public License for more details. | |
14 | ||
15 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 | 16 | License along with the GNU C Library; if not, see |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
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18 | |
19 | #include <inttypes.h> | |
1ed0291c RH |
20 | #include <math.h> |
21 | #include <math_private.h> | |
39793865 | 22 | #include <libm-alias-double.h> |
1004d182 UD |
23 | |
24 | /* | |
25 | * for non-zero, finite x | |
26 | * x = frexp(arg,&exp); | |
27 | * return a double fp quantity x such that 0.5 <= |x| <1.0 | |
28 | * and the corresponding binary exponent "exp". That is | |
29 | * arg = x*2^exp. | |
30 | * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg | |
31 | * with *exp=0. | |
32 | */ | |
33 | ||
34 | ||
35 | double | |
36 | __frexp (double x, int *eptr) | |
37 | { | |
38 | int64_t ix; | |
39 | EXTRACT_WORDS64 (ix, x); | |
40 | int32_t ex = 0x7ff & (ix >> 52); | |
41 | int e = 0; | |
42 | ||
a1ffb40e | 43 | if (__glibc_likely (ex != 0x7ff && x != 0.0)) |
1004d182 UD |
44 | { |
45 | /* Not zero and finite. */ | |
46 | e = ex - 1022; | |
a1ffb40e | 47 | if (__glibc_unlikely (ex == 0)) |
1004d182 UD |
48 | { |
49 | /* Subnormal. */ | |
50 | x *= 0x1p54; | |
51 | EXTRACT_WORDS64 (ix, x); | |
52 | ex = 0x7ff & (ix >> 52); | |
53 | e = ex - 1022 - 54; | |
54 | } | |
55 | ||
56 | ix = (ix & INT64_C (0x800fffffffffffff)) | INT64_C (0x3fe0000000000000); | |
57 | INSERT_WORDS64 (x, ix); | |
58 | } | |
88283451 JM |
59 | else |
60 | /* Quiet signaling NaNs. */ | |
61 | x += x; | |
1004d182 UD |
62 | |
63 | *eptr = e; | |
64 | return x; | |
65 | } | |
39793865 | 66 | libm_alias_double (__frexp, frexp) |