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45f39d45 | 1 | /* Convert a number in multi-precision format to _Float128. |
581c785b | 2 | Copyright (C) 2017-2022 Free Software Foundation, Inc. |
45f39d45 PM |
3 | This file is part of the GNU C Library. |
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 | |
16 | License along with the GNU C Library; if not, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
45f39d45 PM |
18 | |
19 | #include "gmp.h" | |
20 | #include "gmp-impl.h" | |
21 | #include <float.h> | |
22 | #include <math.h> | |
23 | ||
24 | #include "ieee754_float128.h" | |
25 | ||
26 | /* Convert a multi-precision integer of the needed number of bits (113 for | |
27 | binary128) and an integral power of two to a `_Float128' in IEEE854 | |
28 | quad-precision format. */ | |
29 | ||
30 | _Float128 | |
31 | __mpn_construct_float128 (mp_srcptr frac_ptr, int expt, int sign) | |
32 | { | |
33 | union ieee854_float128 u; | |
34 | ||
35 | u.ieee.negative = sign; | |
36 | u.ieee.exponent = expt + IEEE854_FLOAT128_BIAS; | |
37 | #if BITS_PER_MP_LIMB == 32 | |
38 | u.ieee.mantissa3 = frac_ptr[0]; | |
39 | u.ieee.mantissa2 = frac_ptr[1]; | |
40 | u.ieee.mantissa1 = frac_ptr[2]; | |
41 | u.ieee.mantissa0 = frac_ptr[3] & (((mp_limb_t) 1 | |
42 | << (FLT128_MANT_DIG - 96)) - 1); | |
43 | #elif BITS_PER_MP_LIMB == 64 | |
44 | u.ieee.mantissa3 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1); | |
45 | u.ieee.mantissa2 = frac_ptr[0] >> 32; | |
46 | u.ieee.mantissa1 = frac_ptr[1] & (((mp_limb_t) 1 << 32) - 1); | |
47 | u.ieee.mantissa0 = (frac_ptr[1] >> 32) & (((mp_limb_t) 1 | |
48 | << (FLT128_MANT_DIG - 96)) - 1); | |
49 | #else | |
50 | #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for" | |
51 | #endif | |
52 | ||
53 | return u.d; | |
54 | } |