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/* mpfr_init2 -- initialize a floating-point number with given precision
Copyright 2001-2020 Free Software Foundation, Inc.
Contributed by the AriC and Caramba projects, INRIA.
This file is part of the GNU MPFR Library.
The GNU MPFR Library is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 3 of the License, or (at your
option) any later version.
The GNU MPFR Library is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with the GNU MPFR Library; see the file COPYING.LESSER. If not, see
https://www.gnu.org/licenses/ or write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. */
#include "mpfr-impl.h"
MPFR_HOT_FUNCTION_ATTR void
mpfr_init2 (mpfr_ptr x, mpfr_prec_t p)
{
mp_size_t xsize;
mpfr_size_limb_t *tmp;
/* Check if we can represent the number of limbs
* associated to the maximum of mpfr_prec_t*/
MPFR_STAT_STATIC_ASSERT( MP_SIZE_T_MAX >= (MPFR_PREC_MAX/MPFR_BYTES_PER_MP_LIMB) );
/* Check for correct GMP_NUMB_BITS and MPFR_BYTES_PER_MP_LIMB */
MPFR_STAT_STATIC_ASSERT(GMP_NUMB_BITS == MPFR_BYTES_PER_MP_LIMB * CHAR_BIT);
MPFR_STAT_STATIC_ASSERT(sizeof(mp_limb_t) == MPFR_BYTES_PER_MP_LIMB);
/* Check for mp_bits_per_limb (a global variable inside GMP library) */
MPFR_ASSERTN (mp_bits_per_limb == GMP_NUMB_BITS);
/* Check for correct EXP NAN, ZERO & INF in both mpfr.h and mpfr-impl.h */
MPFR_STAT_STATIC_ASSERT( __MPFR_EXP_NAN == MPFR_EXP_NAN );
MPFR_STAT_STATIC_ASSERT( __MPFR_EXP_ZERO == MPFR_EXP_ZERO );
MPFR_STAT_STATIC_ASSERT( __MPFR_EXP_INF == MPFR_EXP_INF );
MPFR_STAT_STATIC_ASSERT( MPFR_EMAX_MAX <= (MPFR_EXP_MAX >> 1) );
MPFR_STAT_STATIC_ASSERT( MPFR_EMIN_MIN >= -(MPFR_EXP_MAX >> 1) );
/* p=1 is not allowed since the rounding to nearest even rule requires at
least two bits of mantissa: the neighbors of 3/2 are 1*2^0 and 1*2^1,
which both have an odd mantissa */
MPFR_ASSERTN (MPFR_PREC_COND (p));
xsize = MPFR_PREC2LIMBS (p);
tmp = (mpfr_size_limb_t *) mpfr_allocate_func(MPFR_MALLOC_SIZE(xsize));
MPFR_PREC(x) = p; /* Set prec */
MPFR_EXP (x) = MPFR_EXP_INVALID; /* make sure that the exp field has a
valid value in the C point of view */
MPFR_SET_POS(x); /* Set a sign */
MPFR_SET_MANT_PTR(x, tmp); /* Set Mantissa ptr */
MPFR_SET_ALLOC_SIZE(x, xsize); /* Fix alloc size of Mantissa */
MPFR_SET_NAN(x); /* initializes to NaN */
}
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