| 1 | /* Convert a number in multi-precision format to _Float128. |
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| 2 | Copyright (C) 2017-2022 Free Software Foundation, Inc. |
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| 3 | This file is part of the GNU C Library. |
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| 4 | |
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| 5 | The GNU C Library is free software; you can redistribute it and/or |
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| 6 | modify it under the terms of the GNU Lesser General Public |
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| 7 | License as published by the Free Software Foundation; either |
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| 8 | version 2.1 of the License, or (at your option) any later version. |
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| 9 | |
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| 10 | The GNU C Library is distributed in the hope that it will be useful, |
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| 11 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
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| 12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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| 13 | Lesser General Public License for more details. |
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| 14 | |
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| 15 | You should have received a copy of the GNU Lesser General Public |
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| 16 | License along with the GNU C Library; if not, see |
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| 17 | <https://www.gnu.org/licenses/>. */ |
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| 18 | |
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| 19 | #include "gmp.h" |
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| 20 | #include "gmp-impl.h" |
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| 21 | #include <float.h> |
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| 22 | #include <math.h> |
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| 23 | |
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| 24 | #include "ieee754_float128.h" |
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| 25 | |
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| 26 | /* Convert a multi-precision integer of the needed number of bits (113 for |
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| 27 | binary128) and an integral power of two to a `_Float128' in IEEE854 |
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| 28 | quad-precision format. */ |
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| 29 | |
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| 30 | _Float128 |
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| 31 | __mpn_construct_float128 (mp_srcptr frac_ptr, int expt, int sign) |
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| 32 | { |
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| 33 | union ieee854_float128 u; |
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| 34 | |
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| 35 | u.ieee.negative = sign; |
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| 36 | u.ieee.exponent = expt + IEEE854_FLOAT128_BIAS; |
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| 37 | #if BITS_PER_MP_LIMB == 32 |
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| 38 | u.ieee.mantissa3 = frac_ptr[0]; |
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| 39 | u.ieee.mantissa2 = frac_ptr[1]; |
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| 40 | u.ieee.mantissa1 = frac_ptr[2]; |
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| 41 | u.ieee.mantissa0 = frac_ptr[3] & (((mp_limb_t) 1 |
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| 42 | << (FLT128_MANT_DIG - 96)) - 1); |
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| 43 | #elif BITS_PER_MP_LIMB == 64 |
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| 44 | u.ieee.mantissa3 = frac_ptr[0] & (((mp_limb_t) 1 << 32) - 1); |
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| 45 | u.ieee.mantissa2 = frac_ptr[0] >> 32; |
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| 46 | u.ieee.mantissa1 = frac_ptr[1] & (((mp_limb_t) 1 << 32) - 1); |
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| 47 | u.ieee.mantissa0 = (frac_ptr[1] >> 32) & (((mp_limb_t) 1 |
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| 48 | << (FLT128_MANT_DIG - 96)) - 1); |
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| 49 | #else |
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| 50 | #error "mp_limb size " BITS_PER_MP_LIMB "not accounted for" |
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| 51 | #endif |
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| 52 | |
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| 53 | return u.d; |
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| 54 | } |
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| 55 | |
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