1 | /* Copyright (C) 1995-2022 Free Software Foundation, Inc. |
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 |
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. |
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 |
12 | Lesser General Public License for more details. |
13 | |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, see |
16 | <https://www.gnu.org/licenses/>. */ |
17 | |
18 | #include "gmp.h" |
19 | #include "gmp-impl.h" |
20 | #include <ieee754.h> |
21 | #include <float.h> |
22 | #include <math.h> |
23 | |
24 | /* Convert a multi-precision integer of the needed number of bits (113 for |
25 | long double) and an integral power of two to a `long double' in IEEE854 |
26 | quad-precision format. */ |
27 | |
28 | long double |
29 | __mpn_construct_long_double (mp_srcptr frac_ptr, int expt, int sign) |
30 | { |
31 | union ieee854_long_double u; |
32 | |
33 | u.ieee.negative = sign; |
34 | u.ieee.exponent = expt + IEEE854_LONG_DOUBLE_BIAS; |
35 | #if BITS_PER_MP_LIMB == 32 |
36 | u.ieee.mantissa3 = frac_ptr[0]; |
37 | u.ieee.mantissa2 = frac_ptr[1]; |
38 | u.ieee.mantissa1 = frac_ptr[2]; |
39 | u.ieee.mantissa0 = frac_ptr[3] & (((mp_limb_t) 1 |
40 | << (LDBL_MANT_DIG - 96)) - 1); |
41 | #elif BITS_PER_MP_LIMB == 64 |
42 | u.ieee.mantissa3 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1); |
43 | u.ieee.mantissa2 = frac_ptr[0] >> 32; |
44 | u.ieee.mantissa1 = frac_ptr[1] & (((mp_limb_t) 1 << 32) - 1); |
45 | u.ieee.mantissa0 = (frac_ptr[1] >> 32) & (((mp_limb_t) 1 |
46 | << (LDBL_MANT_DIG - 96)) - 1); |
47 | #else |
48 | #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for" |
49 | #endif |
50 | |
51 | return u.d; |
52 | } |
53 | |