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/* mpfr_init2 -- initialize a floating-point number with given precision
Copyright 2001, 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
This file is part of the MPFR Library.
The 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 2.1 of the License, or (at your
option) any later version.
The 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 MPFR Library; see the file COPYING.LIB. If not, write to
the Free Software Foundation, Inc., 51 Franklin Place, Fifth Floor, Boston,
MA 02110-1301, USA. */
#include <limits.h>
#include <stdlib.h>
#include "mpfr-impl.h"
void
mpfr_init2 (mpfr_ptr x, mp_prec_t p)
{
mp_size_t xsize;
mp_ptr tmp;
/* Check if we can represent the number of limbs
* associated to the maximum of mpfr_prec_t*/
MPFR_ASSERTN( MP_SIZE_T_MAX >= (MPFR_PREC_MAX/BYTES_PER_MP_LIMB) );
/* Check for correct BITS_PER_MP_LIMB and BYTES_PER_MP_LIMB */
MPFR_ASSERTN( BITS_PER_MP_LIMB == BYTES_PER_MP_LIMB * CHAR_BIT
&& sizeof(mp_limb_t) == BYTES_PER_MP_LIMB );
/* Check for correct EXP NAN, ZERO & INF in both mpfr.h and in mpfr-impl.h */
MPFR_ASSERTN( __MPFR_EXP_NAN == MPFR_EXP_NAN );
MPFR_ASSERTN( __MPFR_EXP_ZERO == MPFR_EXP_ZERO );
MPFR_ASSERTN( __MPFR_EXP_INF == MPFR_EXP_INF );
MPFR_ASSERTN( MPFR_EMAX_MAX <= (MPFR_EXP_MAX >> 1) );
MPFR_ASSERTN( 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 neighbours of 3/2 are 1*2^0 and 1*2^1,
which both have an odd mantissa */
MPFR_ASSERTN(p >= MPFR_PREC_MIN && p <= MPFR_PREC_MAX);
xsize = (mp_size_t) ((p - 1) / BITS_PER_MP_LIMB) + 1;
tmp = (mp_ptr) (*__gmp_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 */
}
#ifdef MPFR_USE_OWN_MPFR_TMP_ALLOC
static unsigned char mpfr_stack_tab[8000000];
unsigned char *mpfr_stack = mpfr_stack_tab;
#endif
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