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d614a753 | 1 | /* Copyright (C) 1995-2020 Free Software Foundation, Inc. |
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2 | This file is part of the GNU C Library. |
3 | ||
4 | The GNU C Library is free software; you can redistribute it and/or | |
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5 | modify it under the terms of the GNU Lesser General Public |
6 | License as published by the Free Software Foundation; either | |
7 | version 2.1 of the License, or (at your option) any later version. | |
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8 | |
9 | The GNU C Library 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 GNU | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
377a515b | 13 | |
41bdb6e2 | 14 | You should have received a copy of the GNU Lesser General Public |
59ba27a6 | 15 | License along with the GNU C Library; if not, see |
5a82c748 | 16 | <https://www.gnu.org/licenses/>. */ |
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17 | |
18 | #include "gmp.h" | |
19 | #include "gmp-impl.h" | |
981993e1 | 20 | #include <ieee754.h> |
28f540f4 | 21 | #include <float.h> |
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22 | #include <math.h> |
23 | ||
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24 | /* Convert a multi-precision integer of the needed number of bits (64 for |
25 | long double) and an integral power of two to a `long double' in IEEE854 | |
bfc04a9f | 26 | extended-precision format. */ |
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27 | |
28 | long double | |
29 | __mpn_construct_long_double (mp_srcptr frac_ptr, int expt, int sign) | |
30 | { | |
31 | union ieee854_long_double u; | |
bfc04a9f | 32 | |
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33 | u.ieee.negative = sign; |
34 | u.ieee.exponent = expt + IEEE854_LONG_DOUBLE_BIAS; | |
35 | #if BITS_PER_MP_LIMB == 32 | |
36 | u.ieee.mantissa1 = frac_ptr[0]; | |
37 | u.ieee.mantissa0 = frac_ptr[1]; | |
38 | #elif BITS_PER_MP_LIMB == 64 | |
d8a5edc2 | 39 | u.ieee.mantissa1 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1); |
fc40c039 | 40 | u.ieee.mantissa0 = frac_ptr[0] >> 32; |
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41 | #else |
42 | #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for" | |
43 | #endif | |
44 | ||
45 | return u.d; | |
46 | } |