1 /* Convert a number in multi-precision format to _Float128. 2 Copyright (C) 2017-2022 Free Software Foundation, Inc. 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 17 <https://www.gnu.org/licenses/>. */ 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 __mpn_construct_float128(mp_srcptr frac_ptr,int expt,int sign)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 } 55