| /* mpfr_init2 -- initialize a floating-point number with given precision |
| |
| Copyright 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009 Free Software Foundation, Inc. |
| Contributed by the Arenaire and Cacao 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 2.1 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.LIB. If not, write to |
| the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, |
| MA 02110-1301, USA. */ |
| |
| #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 |